Scott's Aug 2007

Mid-Atlantic Radar

Scott's August, 2007 Blog
(blog descends chronologically)

Here Today...Gone Tomorrow...And...
Is "Felix" Forming???
Friday, August 31

They come and they go. INVEST 95L has dissipated and INVEST 97L tried to organize but moved inland over Mexico. Two down, two to go.

INVEST 94L: The missing ingredient (surface reflection) has developed and T.D Number Six...or Tropical Storm Felix may now be developing. The system is east of the Windward Islands and has slowed down but still is tracking west. Current view (click image for more ):

Hurricane Hunters are in this afternoon and there is high confidence they will find a depression...winds may possibly already be at 40MPH and if so, this becomes "Felix". The NHC will tip their hand with comments such as this morning's special statement:
"... WATCHES AND WARNINGS MAY BE REQUIRED FOR PORTIONS OF THE WINDWARD ISLANDS...AND ALL INTERESTS IN THAT AREA SHOULD BE READY TO TAKE QUICK ACTION...IF NECESSARY. REGARDLESS OF DEVELOPMENT...HEAVY RAIN AND STRONG GUSTY WINDS WILL SPREAD OVER THE WINDWARD ISLANDS LATER TODAY AND TONIGHT."

We'll see if they wait until recon is in before making Invest 94L "official". If data supports it, they may go with a "T.D." this morning as the system is approaching the islands and advisory information needs to be issued. Potential landfall "first guess" would be near the Honduras/Nicaragua coastal border. Interesting, the UKMET, GFS and the GFDL still don't have this system developing but clearly, it is organizing. As soon as the storm becomes "official" you'll find real-time info at our HurricaneCenter.

INVEST 96L: This system continues trying and you can see an elongated "open eye" in this visible image (available only during daylight):

Strong thunderstorms are refiring off to the Northeast...displaced away from the center due to shear. Very difficult to earn "named status" once north of 38° and this probably will be relegated to a mini Nor'easter. The Invest should track to the Northeast and off shore winds increase and back from the NE to NW into the weekend. Without recon it is difficult to determine if this is a warm-core cyclone so Invest 96L probably blows by and is forgotten (IMO, an extra tropical storm but I don't work at the NHC!).

A frontal boundary draped from the Coast of Maine, across the Alleghany Mountains and down to Dallas, TX will keep this storm away from the New England coast...but a pretty good chop today and tomorrow off the Cape!

Invests-A-Poppin' !
Four Invests in Atlantic = Welcome to "Prime Time" Hurricane Season.
Thursday, August 30

You don't need a calendar to know September is almost here! Two new Invests today (along with Easter Pac action from Gil and a new Invest).

Map of four Atlantic Invests (note: this map is NOT updated and is current only on Thursday morning)

Fortunately, none of the Atlantic Invests are immediate threats, but let's run down the line-up:

Invest 94L: Will reach the Lesser Antilles late tomorrow or Saturday morning. No changes to yesterday's thinking: development unlikely until a surface reflection appears and that probably doesn't happen until the system is in the Caribbean...if at all.

Invest 95L: Has closed off and developed a Low Pressure center but generally is devoid of convection. It is being adversely affected by new Invest 96L and may dissipate, especially if Invest 96L intensifies. It 95L holds together it will track Northeast away from land (fish storm).

Invest 96L: New Invest is located this morning due east of Cape Hatteras, NC. Invest 96L shows nicely by clicking HERE. Some models are developing this into a Tropical Storm but like Invest 95L, it will track Northeast away from the US coast. Systems that develop off NC or VA tend to move quickly so we'll see how this system develops. Of the two along the Eastern Seaboard, this disturbance looks to be the stronger.

Invest 97L: Located in the Bay of Campeche (SW GOM). Very close to land but may threaten Mexico as a Tropical Depression bringing in another batch of moderate to heavy rain.

We're furiously running model maps on both Invest 94L and 95L in our Premium Service weather section.
Ample activity but no immediate threats. Welcome to Prime Time for hurricane season, 2007.

Invest 94L Still Perking...And...
Invest 95L Off the SEUS Coast. Next Tropical Depression?
Wednesday, August 29

Invest 94L: There simply isn't much at the surface with this Invest and until that changes, nothin' doin'. This afternoon's 5:30PM Outlook from the NHC is more bullish than am I: ALTHOUGH THIS ACTIVITY IS
CURRENTLY DISORGANIZED...ENVIRONMENTAL CONDITIONS ARE EXPECTED TO GRADUALLY BECOME MORE FAVORABLE FOR DEVELOPMENT AS THE SYSTEM MOVES WESTWARD AT 15 TO 20 MPH.

Bottom line is the Invest needs to spin down to the surface while increasing convection close to the Low Pressure center. While conditions are somewhat favorable, the Global models generally are not getting this going. Dry air intrusion continues to vex this system but will have far less impact after the disturbance crosses the Islands and gets into the Caribbean...probably on Friday. So, we continue to closely monitor and will update here as needed.

Invest 95L: The "blog" off the Carolinas became our latest Invest: 95L. Click HERE for current view. Models are strongly suggesting this becomes a Tropical Depression within two days and it will be interesting to see how this develops. A trof moves in and sets up off the East Coast as a Cold Front crosses the Mid-Atlantic area tomorrow night and should settle over the Gulf Coast and north Florida by Saturday. The likely solution is Invest 95 becomes a TD or perhaps a Sub Tropical Depression and will head Northeast...away from the coast. I don't see a viable way the system will stop and track west or Northwest toward FL or the SEUS coast. We're running model maps on both Invest 94L and 95L in our Premium Service weather section.

Invest 94L...And...
Katrina Two Years Later.
Tuesday, , August 28

Invest 94L: A wave crossing the Atlantic has now become Invest 94L. Current view here. While rather anemic in appearance right now, there is little wind shear and some development is possible. The Invest must survive extensive dry air ahead and to the north (from link above, click Enhanced Water Vapor). The Euro heads up toward the Bahamas (and East Coast?). I am not sold on this idea right now...but that certainly COULD change! Meanwhile, the GFS just can't find the storm. Hurricane models track either into South America or the lower Lesser Antilles late Friday. Current maps available at our Premium Service weather section. Invest 94L is worthy of watching but rapid intensification will not occur.

Katrina: This week marks the second "anniversary" of Katrina. Last year, I wrote daily blog entries entitled: "KATRINA: Day-By-Day" to review the storm's daily progress. Also included are daily model maps to show how and why the storm was forecast as it was. That series is located in our HurricaneCenter and available for reading by clicking here.

I still regularly chat with folks in and around NOLA...I love the city and what is happening (and NOT happening) in New Orleans and the Gulf Coast tugs at the heart every day. The more people who read "KATRINA: Day-By-Day" and watch other specials in the media the better. Katrina's anniversaries are National reminders of how much work remains. It also serves as a warning that if a catastrophe befalls your home town, you and those still living in Katrina's wake will have much in common. If you need a jolt about how things really are post-Katrina", I urge you to watch "Children of the Storm" on CNN. Link is here.

Quiet In The Tropics...*SNAP*...
Loud In The Mid-Atlantic!
Sunday, August 26

Tropics: The "blob" over the Southwest Caribbean previously sniffed out by the models is now in the extreme Southwest GOM and will move inland with no development. Elsewhere, nothing brewing in the next 24 hours.

Stormy Mid-Atlantic: The Cold Front mentioned in Friday's blog is crossing the region and will trigger another round of storms today. A weak trof is located ahead of the Front roughly from Richmond, VA to Dothan, MS. Severe parameters are modest but with the heating of the day triggering early afternoon storms, additional outflow boundaries will head to SE VA and the Carolina Piedmont lifting up some strong storms as we approach evening. Supercells and microbursts are possible with wind damage being the primary threat today. Cooler and drier air moves in on High Pressure behind the Front and we'll finally push the persistent Southeast/Bermuda Ridge off shore...at least for a while!

Two days of SVR in the region provided alot of windshield time and some modest chasing results:

Friday: A very strong cell crossed the Blue Ridge and moved along I-64. I was in Charlottesville, VA and heavy traffic kept me from getting under the cell but still was able to watch. As the storm passed to my southeast, I noticed these Mamas (mammatus) clouds on the back sheared anvil of the storm (click image to enlarge):

A short while later we were treated to a double rainbow (click image to enlarge):

Pix taken on my cell phone certainly don't tell the whole story, but you get the idea...pretty good storm!

Saturday: Ghastly heat with dew points in the lower 70's set the stage for numerous strong to severe storms, especially across NOVA and Eastern PA. The Boy Scout office in Waynesboro, VA was under an apparent microburst late Saturday afternoon. A flag pole was bent over by strong wind (click any picture to enlarge):

Poles supporting a small retaining fence were bent (I've seen this after a hurricane but never in a microburst!)

A tree measuring 2' in diameter was toppled by winds:

There was water damage inside the building and rain was also blown in under a door. From my "unofficial" examination, this was not straight line wind damage and there was no rotation. Similar damage nearby led me to believe this was a potent wet microburst.

After nearly hydroplaning off US Route 11, I drove to a home that sustained slight damage from a lightning strike. I was told if a picture was taken I'd lose my cell phone and camera, so nothing here to show you ;-)

Upon returning to the office in Lexington another cluster of storms trained over the area with very vivid lightning. As I was downloading photos, I heard a very loud *SNAP!* outside the window...knowing what that means, I lifted my feet off the floor and jerked my hands from the keyboard but before doing so I saw a flash and heard an immediate KA-BOOM! I don't know where the lightning hit ground (no tree/structure damage) but it was close. The "snap" I heard was a static discharge from the lightning completing its circuit between the cloud and the ground; this static electricity probably came down our weather station ground cable.

You do not want to be so close to lightning so as to hear the *snap*. In our Photo Gallery, you'll find an amazing video sent to us of a near strike with the dreaded *snap*. Click HERE and turn it up!

For today, clouds will need to clear out so daytime heating can get underway. The frontal boundary should be east of the Blue Ridge by "prime time" this afternoon, so most of the thunderstorm activity looks to be across southeastern VA and into Eastern NC as noted above. Can't rule out some storms firing up along the VA I-81 corridor into this evening.

Reminder: we invite you to send us your storm photos! It's easy and fun! Details HERE.

Next blog will be on Tuesday unless things get cranking up today!

UPDATE: 3:20PM:

The "blob" in the SW Gulf of Mexico (Bay of Campeche) has become Invest 93L. I am uncertain why as even if it were to become a depression it will quickly move onshore and into Mexico...with no further development. Premium Service members will find current maps and data now online.

It's Sonny & Cher! Singing Their Pop Favorite:
"And The HEAT Goes On".
Friday, August 24

The hideous Heat Ridge that steered Erin and Dean to the south continues a killer grip on much of the Nation. And now, a stalled out Stationary Front over the Mid-Atlantic and High Pressure centered over the Southeast are moving over the Atlantic...clearing the way for the return of the blowtorch! A near textbook Bermuda High setup returns and will pump ample low level hot and humid air all the way into New England this weekend. High temps? Let's add 10 to perhaps 15 degrees over yesterday for the Northeast....5 to 10 degrees over yesterday for the Mid-Atlantic.

Watch the temperatures soar today and tomorrow as the High moves off shore and the juicy airmass returns on Southwest flow (click map for our exclusive Mesonet page):

There is the specter of hope for slight relief Sunday as a Cold Front approaches the East. Showers, rain and some storms are possible along and ahead of the front, expected to cross the region late Sunday. The weak frontal boundary will wash out over the Carolinas so there's not much of a cool down for the Southeast. Models are pointing to temps at or maybe a little below normal for the latter half of next week...that would be nice. Computer guidance often underestimates how quickly this Ridge can bounce back so your local forecast may again heat up next week.

TROPICS: Nothing brewing at the moment. A couple models are trying to crank up trouble in the far SW Caribbean, just off the coast of Central America. No tropical development is expected this weekend.

Dean Makes Landfall #2...All Quiet Elsewhere.
Wednesday, August 22

Dean: Landfall #2 update from TPC/NHC:

1150 AM CDT WED AUG 22 2007

THE CENTER OF HURRICANE DEAN MADE LANDFALL IN MEXICO NEAR THE TOWN OF TECOLUTLA...JUST EAST OF GUTIERREZ ZAMORA AND ABOUT 40 MILES SOUTH-SOUTHEAST OF TUXPAN AT ABOUT 1130 AM CDT...1630 UTC. THE ESTIMATED INTENSITY OF DEAN AT LANDFALL WAS 100 MPH...160 KPH....CATEGORY TWO ON THE SAFFIR-SIMPSON HURRICANE SCALE.

Props again go to TPC/NHC for excellent forecasting of this devastating, long-track storm. Our Premium Service hurricane model maps calculate the error margin for NHC and the models. Here's TPC/NHC through Forecast/Advisory 38 (in miles):

12hr avg:   24
24hr avg:   45
36hr avg:   69
48hr avg:   98
72hr avg: 171
96hr avg: 232
120hr avg:316

Overall avg: 114

The AVNI and the AEMI (multi-model ensemble of the AVN) did extremely well as did the EGR2 (from the UKMET). Full model analysis is available to Premium Service hurricane model map subscribers.

Invest 92L: The Invest was dropped last night as it remains a disorganized open wave approaching Florida. Current Southeastern US view from our HurricaneCenter HERE Despite modest wind shear, this system never pulled together and looking at mid and upper level charts, I'm wondering if Dean's massive outflow has disrupted potential development. Rain for FLA but no organized storm.

I'll be away from the office on Thursday, so the next post here at the blog will be Friday. While there appears to be no pending tropical development, and quick hit updates will appear on our news feed.

Dean Makes Landfall #1...Invest 92L Flounders But May Be Florida Bound.
Tuesday, August 21

Dean: The hurricane made first landfall around 4:30AM EDT and is weakening (still a "3") inland. Dean ejects into the western GOM this evening and makes landfall #2 near or slightly north of Veracruz, Mexico on Wednesday. Dean is the first Cat-5 since Wilma in 2005 (also made a brief landfall on the Yucatan) and the first Cat-5 landfalling hurricane in North America in 15 years.

INVEST 92L: Not much new. Slow development is possible but the Invest remains disorganized this morning. It is expected to track west (thanks to the High Pressure Ridge). The 6Z GFS brings it to Miami but only with 20 MPH winds...and then moves near Tampa and into the NE Gulf. with winds below 20 MPH. CMC brings the Invest inland near Daytona Beach...also extremely weak.

Click HERE for satellite imagery of Invest 92 located NE of Haiti.

INVEST 92L Could Get Interesting.
Dean Could Become a Cat-5!
Monday, August 20

INVEST 92L: A "blob" located NE of the Leeward Islands and ESE of the Bahamas is now Invest 92L. Position for the early models at 12Z today was: 22.3° N | 54.7° W. This, btw, is what the CMC model was going bonkers over yesterday and it would be quite a coup if it was the first to sniff out this storm. Interestingly, the CMC this morning has a weaker storm off Florida than it did yesterday. Some of the early models bring this up to a named storm and while the GFS tracks it across Dade-Broward and then into the Gulf, it is very weak at this time. We will watch and wait. Premium Service hurricane model map subscribers will find current maps and data on Invest 92L now online.

The massive High Pressure Ridge we've discussed seemingly forever will be a player with Invest 92L. While the Invest is fairly far north (22.3°) my initial opinion is it will not track with a northerly component for long, nor will it quickly recurve and be a "fish storm". Remembering high pressure rotates clockwise, there really is only one direction for the disturbance to travel. I'd give Invest 92L a break-even shot at developing and interests south of Wilmington, NC should keep informed on any additional development from the Invest. Check into our blog and be sure to visit our news feed.

DEAN: Preliminary damage reports coming in from Jamaica are extensive but the eye staying just off shore (50 miles) spared countless lives and untold dollars additional damage. Virtually all of Jamaica was under sustained hurricane winds and a Cat-2 wind field probably extended over much of the southern portions of the island. Dean is expected to become a Cat-5 prior to landfall on the Yucatan and the storm is fully expected to maintain a westerly track...making second and final landfall near Tampico, Mexico.

UPDATE: 8:50PM:

DEAN: Now a Category-5 hurricane. Landfall anticipated on the Yucatan mid-morning Tuesday...horrific winds and surge well in advance...this is a perpendicular hit.

From our Premium Service, here's a close-up of tonight's forecast track and the 18Z models:

INVEST 92L: Global models really are not picking up on the still open wave. The CMC, which was bonkers, now has tamped down enthusiasm and shows a modest Low in another 24 hours. There are two options: west or "Another One Bites The Dust" (great Queen song). This Ridge is too formidable and Invest 92L either dissipates or heads the Bahamas and perhaps South Florida.

The AVN/GFS has backed off the storm after 24 hours while the SHIP and DSHP models crank it to a hurricane in four days.

We're tracking Invest 92L and of course Dean at our Premium Service section.

Interests in the Bahamas and Florida should be alert for potential development. I don't think this would get north of Hilton Head Island, SC, but folks along the Southeast coast should also monitor any future development.

Is It Ivan All Over For Jamaica???
Forecast Track Continues To Head South...Away From US
Sunday, August 19

Three years ago, Ivan terrorized Jamaicans by taking a bead on the island only to skim the southern coast. Plenty of damage but Jamaica rebounded. Is Dean doing the same thing???

From our Premium Service hurricane model maps, here's a zoom-in on the models and the NHC "official" track as of 9AM Sunday. This map will NOT be current after 11AM EDT today!!!

Incredibly, yesterday's jogs could be today's blessings. To be sure, hurricane winds and flooding will plague the southern side of the island as hurricane winds extend 60 miles from the center. Dean is moving WNW and if there is no additional northern shift in the track the eye will get close...but not hit...the island! Let's hope that is the trend...Jamaica must be prepared for a large hurricane but may again have dodged the direct hit bullet.

I will update this map later this afternoon as Dean takes a final approach to Jamaica.

Medium range: Dean is forecast to make landfall as a major hurricane while spending more time over the Yucatan; this will produce extensive damage and flooding. The tropical cyclone will emerge in the SW GOM as a weaker hurricane before coming inland for good near Tampico, Mexico. As for the models, only the NAM (Eta) recurves Dean toward the US. It is seeing a weakness in the Ridge as the Upper Level Low retrogrades into the western GOM (see water vapor loop below). The NAM, however, is not considered a reliable tropical forecasting model..

UPDATE: 12:03PM:

Close up from our Premium Service hurricane model maps, as of 11AM EDT:

Purple dot is the forecast position at 11PM EDT tonight...extremely close to Jamaica. A very slight wobble or jog (not uncommon with intense hurricanes) can shift this track slightly north or south...therefore emergency plans on the island must be hurried to completion.

I am honored by the number of Jamaicans who regularly visit Mid-Atlantic WX.com and we're working hard to continue providing additional information to you and everyone else in the potential path of Hurricane Dean.
We're trying to keep a steady stream of info on our news feed; items such as pressure or other quick changes appear there. Click HERE for our news feed.

FLORIDA HIT NEXT WEEK??? I've received a PM and emails about this morning's Canadian CMC model's "sneak attack" storm next week.

Here's what the CMC has for next Thursday night (click image to enlarge):
I usually don't mention these blips, but I'm guessing it is being plastered all over the weather chats and boards and so I need to comment. I can find NO OTHER MODEL SUPPORT for this event...REPEAT...NONE at this time. The CMC has a long and proud tradition of popping up big storms and then dropping them 12 hours later. Obviously, we watch everything here at Mid-Atlantic WX.com and I'll have a follow-up comment tonight, along with an updated Dean discussion.

UPDATE: 5:10PM:

Close-up of Dean's position.

NHC forecast track is West (280°). There appears to be two eyewalls and it is possible slight wobbles may continue this evening. Pressure at 903M mb.

As the storm will be south of Kingston shortly, here's the last zoom-in or track and models Premium Service hurricane model maps:

Hurricane force winds now hitting the southern portion of the island with tropical storm winds buffeting all of Jamaica. It would take a major jog to the NW or WNW to get Dean's eye totally over the island, however the winds, storms and flooding will still be very significant and could be extremely bad along southern Jamaica.
Everything operational at our HurricaneCenter. Power 106 radio from Kingston is still on the air although it is now faint and scratchy, if you can get into the servers. This is caused by wind fade and rain fade (same as if you own a satellite dish). Haven't heard any ground observations through the static but still tuned in here.

Dean May Bring Catastrophic Damage to Jamaica.
Saturday, August 18

Not since the Saturday before Katrina's Louisiana landfall have I had such a sense of despondency about what may come from a hurricane. Jamaica is in grave danger. The island has been most fortunate over the years; the last "hit" was from Gilbert 19 years ago and that was at Cat-3 strength. If Dean continues on the current track, he will hit Jamaica as a Cat-4...the eye may actually pass over the island. Current zoom-in forecast track below (click graphic for more images)

As this is written (12:30PM) the hurricane is forecast to become a Cat-5 prior to making a DIRECT HIT on the eastern side of the island near Kingston,,,and literally cross the full length before exiting back into the Caribbean. Jamaica is somewhat mountainous and Dean will weaken if the eye does cross the island however he will not be there long. The storm surge, flooding and wind damage produced by this hurricane may be nothing short of catastrophic for this wonderful island. We must now watch and wait. Attempts to link Jamaican radio and web cams have been unsuccessful; if you have found a link that is working, please send so I can share here on the blog. Email me here at this special address.. The Cayman Islands radio web stream is also down but I'll keep looking and hope one of you find something!

Here is a link for storm reports coming out of Jamaica: http://stormcarib.com/reports/current/jamaica.shtml.

Radar from Jamaica is online here: http://www.metservice.gov.jm/radarpage.asp.

Another lament of mine is most Ham radio VOIP is gone from the Internet after the 2005 season. I'm checking for any amateur radio nets out of the Caribbean

This is a close call for Cuba and and any additional northwest jog gets the hurricane force winds near the southern coast of Cuba. The Cayman Islands could also be in the cross-hair on Monday.

While there is confidence in the forecast track, Dean is an extremely powerful tropical cyclone and will undergo Eyewall Replacement Cycles (ERC). This appears to be happening now as the eye has shrunk and Hurricane Hunters reported a partial double eyewall. This briefly weakens the storm and can also produce little jogs that can shift the track by several miles. As such, we do not know with precision exactly where the eye will track but there isn't any change in overall thinking. As noted last night here, the GFDL model shifted well to the west and is now well south of Houston, TX, and the "official" track brings Dean over the tip of the Yucatan and then inland over northern Mexico as an intense hurricane.

If you look at yesterday's blog below you'll see the current Water Vapor Loop and see the Upper Level Low is weakening and moving west. Meanwhile, this savage High Pressure Ridge that relentlessly is pumping the mercury up again in the East, shows no sign of weakening. This Ridge (as discussed at length yesterday) will expand to the north of Dean and I can't make the case the hurricane gets much north of Corpus Christi, Texas.

Perhaps a brief update tonight, dependant upon next recon flight and receiving any Caribbean links from y'all ;-)
Otherwise, next full discussion Sunday morning.

UPDATE: 11:40PM:

Quick comment on 11PM F/A. Pressure down to 918 mb...among the lowest EVER recorded in the Caribbean. Dean is finishing an Eyewall Replacement Cycle (ERC) and while doing so, jogged somewhat sharply to the west. The result is a shift south with the NHC "official" track. It is still quite possible the eye crosses Jamaica but it may brush or stay just south of the island. Serious damage either way. Wind speed dropped...but do NOT be fooled by this as it is common during an ERC. When there's two or even three walls the storm is less stable, the center expands and winds will weaken. When the eye contracts on Sunday the winds will quickly accelerate and Cat-5 is possible, if not probable. The last few frames on the animated loop clearly showed Dean turning more to the northwest but now appears west once again. We'll need to wait until the eye contracts and a steadier track resumes, but 918 millibars shows this is an extremely powerful storm.

I was sent a link to another Jamaica radio station streaming but it is difficult to get in. Give it a try:
http://go-jamaica.com/power/ ...and thanks to Erika in J'ville F-L-A for sending the info ;-).

Have a good night.

Mean Dean May Strengthen to Cat-5 And Aims at Jamaica While Throwing a Scare From Brownsville to Baton Rouge.
Friday, August 17

Dr. Lexion Avila wrote this afternoon's NHC Discussion and it worth as look by clicking HERE. Let's try for some visual enhancements to Avila's Discussion.

Here is the current 3 hour Water Vapor Loop (with credit and thanks given to Unisys):

While Dean is evident, recall we have been discussing here for a few days an Upper Level Low (ULL) off the Southeast US Coast. Look at the Bahamas and you'll see a mid/upper level swirl: this the feature we've talked about and Avila references in the 5PM Discussion.

Remember a mid or upper level low is not at the surface. To see what's happening there, we'll look at the 18Z GFS (click map to enlarge):

Again, you'll quickly spot Dean's surface low pressure center, but notice the large, elongated surface High Pressure area over the Atlantic. Hard to see above, but if you click and enlarge you spot the 1016 isobar all the way to Dallas, TX. Look again and you'll see Dean punching up into the fringe 1012 isobar. No real worries as High Pressure is what has helped keep the storm tracking west...this generally will continue into the weekend.

And this is where we are right now. So, everyone is asking what comes next?

Dean is ramping up in excellent conditions. The Upper Level Low seen above should move west and will weaken. Let's see how the GFS wants to set things up this weekend. Below is the map for 2PM EDT on Sunday (again, please click to enlarge):

The top of Dean is observed in the lower right. Look where High Pressure is now centered...right off Virginia. And follow where the 1016 isobar goes: still across the northern GOM and now over central Texas. There does not appear to be any reason for Dean to turn Northwest and try denting into that Ridge and this is why most models and the "official" forecast track take the hurricane near or over Jamaica , then onto the Yucatan Peninsula.

Now the conundrum. If you read yesterday' blog (below), you'll remember I wondered why the GFDL and the Euro models keep pushing the northern edge or past NHC's "cone of probability". Well, Avila did the same in this afternoon's 5PM Discussion. I still do not know why some models push Dean over Western Cuba and into Eastern Texas or Louisiana. While the Euro is not this far to the North, the GFDL (good with Erin and Dean) goes inland west of NOLA . Avila and the NHC are curious as well and so they will be very careful in how they present each Forecast Advisory package; the last thing they will do is narrow "the cone"...at least not until well into the weekend.

Maybe these models think Dean will interact with the ULL once it moves west and thus create a weakness in the Ridge for the storm to shift to the NW or NNW. I don't know. I have a reliable contact at Hurricane Research Division whom I've twice emailed about this only to find out he is airborne on missions. Still, I'd feel better if these models resume a more westerly track.

The current Forecast Advisory is a direct cross-island hit for Jamaica. I see no reason why this tropical cyclone will not reach Cat-5 status once is gets over much warmer water and under very little wind shear. A hurricane can't stay Cat-5 forever and one hopes some interaction with islands to the north will weaken on approach, but this could be most grave if the current track verifies.

Next update here at the blog around Noon tomorrow. Check our News Feed for quick hit updates.

UPDATE: 9:25PM:

I know I earlier wrote next update tomorrow but had to jump on the blog for important updates and a minor rant.

Intensity: Dean now a Cat-4. I see nothing to preclude the storm from becoming a Cat-5 before approach to Jamaica. Dean is becoming a large storm with an ever widening tropical storm wind field. If the storm comes in near Brownsville, it is likely there will be storm surge well up into Galveston Bay. Just something to consider.

18Z Models: A good portion of today's earlier blog opined about some models stay well north of the NHC "cone". Some encouraging news from the 18Z models (maybe). With the exception of the clueless CLP5 (known as the 5-day Clipper), there was a southwest shift in the 18Z models...including the GFLD. That model jumped from near Baton Rouge west to Houston. I know many Texans read this blog, especially from Metro Houston and I cautiously say this is encouraging. We have five days to go and if the GFDL keeps migrating southwest, it will be in line with virtually all other models. Certainly will be a nail biter weekend. If you're interested in getting hurricane models 24/7, consider our Premium Service hurricane model maps. and cell phone notification service.

Rant: I watched some video on Fox of Dean crossing the Lesser Antilles and I had my annual cussing outburst (fortunately, no one was home). There on TV, as hurricane winds hit a hotel, are three guys standing behine plate glass sliding doors. The typical masking tape "X" is blowing off the outside of the glass and these gutys are leaning into the glass door to keep it from blowing in. I've been on a mission for years to bust two weather myths: there is no such thing as heat lightning, and masking tape on windows and doors is idiotic. The time spent putting tape on a window can be better used in making oneself safe. Why do people actually think a piece of masking (or duct) tape prevent a tree or other object from breaking the glass. And how is it people don't understand putting your palms on plate glass doesn't stop it from exploding inward? I was in Portlant, Maine for Hurricanes Gloria and Bob and can show you today masking tape cooked onto windows! I just don't get it.

Enough of Erin...And...Dean Will Get Mean!
Thursday, August 16

Erin sloshed in this morning and will continue pushing bands of heavy rain inland past I-35. Click HERE for our animated Radar loop from Houston/Galveston. Houston has a Flood Warning currently in effect. I've seen wind reports of 40-45MPH...certainly modest for hardy Texans along the Gulf Coast. Surge to the north of landfall was around 2 feet. No storm damage reports or tornado activity reported from the Storm Prediction Center. Erin has been downgraded to a Tropical Depression and the final NHC Forecast Advisory has been issued.

Dean: Dean became a Cat-1 hurricane this morning and while not yet in primo conditions, the tropical cyclone is now becoming well organized. Current enhanced satellite (click graphic for more):

Dean is now growing to a more expansive storm and should reach the Islands tomorrow as a borderline Cat-2. From there, into the Caribbean and no major changes from my previous thought laid out here in the blog. The Upper Level Low over the Bahamas seen in this Water Vapor loop will will move away and won't catch Dean. Another feature in that loop is an Upper Level Low plainly seen to Dean's north out in the Atlantic. Dean is still moving along at a quick pace and this ULL won't be much of a player. So, Dean barrels through the Lesser Antilles with potent wind, surge and tremendous rains. Hurricane Hunters now out there are reporting 85 knot winds

A look at the models from our Premium Service section shows good agreement amongst most computer modeling data. The hurricane strengthens, perhaps to a Cat-4, passes extremely close to Jamaica and then slams into the Yucatan. If this hurricane swells to a high 3 or a Cat-4 there isn't much downstream to make it recurve up into the central Gulf of Mexico. However, the European (ECMWF) and the US GFDL still are on the northern edge of all other models. This bothers me. The Euro has been pretty good again this season and the GFDL gave good service with Erin, and is good with Dean thus far. I do not know what these two models are "seeing"; there's no trof diving down into the Gulf, nor is the Ridge going to swell and become so strong so as to affect a large hurricane down in the central Caribbean. And the Upper Low over the Bahamas is expected to migrate west...it is heading to TX so Dean shouldn't be heading to the north central Gulf coast. Were this happening with most other models, I'd disregard but it is raising an eyebrow here. The UKMET has been good with these storms and except for one run taking Dean north toward the Bahamas, it has been steadfast south of Jamaica, into the Yucatan. The GFS and GFSO are back from bringing Dean toward Florida and are rock steady along with the NHC forecast track. With such excellent agreement among models it is easy to stick a fork in the track...while it certainly is reasonable, I certain will not sound the all clear for Texas or Louisiana...y'all must remain very vigilant...especially Houston/Galveston down the coast. If Dean does hit the Yucatan, he will certainly weaken, but there is the Western Gulf on the other side of the Peninsula.

Hurricane Dean is on a very similar track and forecast as a storm you may recall: Hurricane Allen in 1980.

Next update here on the blog will be Friday morning.

Tropical Storm Erin To Tex/Mex Coast...
Dean Heads to the Caribbean.
Wednesday, August 15

Dean: We won't get super technical this morning but it appears a consensus is beginning to form. The 0Z and 6Z models have backed off digging a sharp trof down along the SEUS coast. The idea of a mid to upper level low seems to be "Gone With The Wind" as well...therefore there isn't much to pull Dean to the north...toward Florida or the East Coast. Here's this morning's model map from our Premium Service section:

NOTE: this map will NOT be current after 12 Noon today! For information on getting real-time model maps, click HERE.

Florida folks and those along the East Coast should NOT stand down just yet...let's make certain there is no interaction between the tropical cyclone and the advancing trof! Dean will be a "hit" for the central and upper Lesser Antilles islands and this track keeps the center over water and away from land ...as such, The Blade (Dominican Republic) may have limited effect on disrupting the cyclone's inflow. This would put a major hurricane (red on the above map) near southern Cuba and Jamaica early next week. If my hunch about the Ridge over the Atlantic expanding inland, Dean will probably begin recurving up into the Gulf of Mexico. Not good.

ERIN: Banding features, stronger thunderstorms and better organization all boost confidence this is a tropical storm that will come inland tomorrow afternoon along the South Texas coast. Current information, including watches and warnings at our HurricaneCenter.

Current enhanced view of Tropical Depression Five (click graphic for more satellite loops of the GOM):

Prior commitments and busy work load in the HurricaneCenter mean no additional update today or a "quickie" after 11PM tonight...please check back then. Thanks!

UPDATE: 10:25PM:

Erin: Enhanced satellite image above shows spiral bands spinning inland tonight from the Tex/Mex border up to Louisiana. Here's a zoom-in version of the forecast track from our HurricaneCenter. Click the graphic for more interactive maps

This track brings the center inland near Corpus Christi, TX tomorrow afternoon. Conditions are prime for this to crank up to around 55MPH upon landfall. The bigger story is the potential for substantial inland flooding as the mountains will provide orographic lift and squeeze out several inches of rain. Texans west of DFW and Houston are getting ready for what could be a serious flooding event.

The storm name "Erin" brings me back to bad memories. Storm names are on a six year cycle and Hurricane Erin was southeast of New York City on September 11, 2001. I saved a satellite image from that morning showing Erin's outflow and smoke plumes emanating from Lower Manhattan. That visual is what I recall with every mention of a storm named "Erin".

Dean: The tropical storm is ingesting some dry air (bad for developing into a hurricane). Despite this, we see signs of an eyewall developing. Wind shear will only be in the 5-10 know range...not a problem for a strong tropical storm. Dry air will persist but there remains every reason to believe Dean will become a hurricane on Thursday. Hurricane winds and storm surge will be a major problem as the storm crosses the islands. Here's a close-up of Dean's forecast track, also from our HurricaneCenter. Click the graphic for more interactive maps.
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This track puts Dean's center extremely close to Martinique before heading into the Caribbean. Next is very warm water and intensification to Cat-3 status. Dean is forecast to approach Jamaica early next week before looking at either the Yucatan or west-central Cuba.

The developing TUTT off the US coast over the Bahamas worries me, although all reliable models and the NHC keep Dean on a WNW track. As commented this morning, Florida and the SEUS coastline probably are in the clear...but as Grissom always remarked on CSI: "Assume Nothing!". But, it certainly looks like we'll have a major hurricane in the Caribbean and not approaching Florida. For now: hurricane tomorrow, Lesser Antilles on Friday, significant strengthening this weekend in the Caribbean.

Tropical Depression #4 Now Dean...
Hurricane Hunters Into Invest 91L Later Today...T.D #5???
Tuesday, August 14

Dean: 11AM Forecast Advisory this morning brings T.D 4 to Tropical Storm status. Interesting comment from the NHC: THE DEPRESSION HAS REACHED TROPICAL STORM STATUS AND ALSO THAT THE CENTER IS LOCATED FARTHER TO THE SOUTH AND WEST THAN PREVIOUSLY INDICATED. Note how the forecast position is to the southwest of the previous location:

It is probable that the center did not jog to the SW, but rather they are now better able to get an accurate fix on the location. Wind shear persists near 20 knots so it is also possible the center is shifting...either way, slight adjustments to the "official" track have been made. The storm is now forecast to track very close to Puerto Rico as a strong Cat-2 on Sunday.

Questions and concerns in last night's blog remain: timing/location of an approaching trof, Upper Level Low and Ridging all become critical players. Odd as it sounds, anyone from the Texas coast to New England is in the game! At this time I have no changes to last night's comment on the distinct probability of "...a hurricane somewhere along the east coast of the US around August 21st". In this comment I certainly include the State of Florida.

Invest 91L: This disturbance is tracking NW and looks to roll inland near the Mexico/Texas border. Time is not on the storm's side but this could become a Tropical Depression today...especially with good info from the upcoming Hurricane Hunter flight. Very heavy rains will spin inland and storms with isolated tornadoes are possible.

Another update here at the blog this evening after we know more on the GOM storm. Please continue to monitor developments with Dean at our HurricaneCenter. Get more information on our Premium Service hurricane model maps by clicking HERE.

UPDATE: 9:50PM: Brief update as there is very little "real" news to report tonight...except we may have a new TROPICAL STORM in the Gulf!

Invest 91L: MAY BECOME A TD OR NAMED STORM TONIGHT AT 11!!! Hurricane Hunters flight wasn't encouraging but Invest 91L is cranking up! Click HERE for current 5 hour loop. Note the very impressive and more organized convective flare up this evening. Here's the current still enhanced image from our HurricaneCenter:

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I would not be surprised if Invest 91L became Tropical Depression #5 or Erin tonight or at 5AM tomorrow. Folks along the Gulf coast from TX to NOLA need to be prepared for the possibility of Tropical Storm Watches or Warnings issued at anytime! The storm doesn't have much time before landfall, but a tropical storm is VERY possible! Tonight or tomorrow morning the NHC could go with a Tropical Depression (doesn't look like a cyclone on satellite right now) and also issue Tropical Storm watches...or Warnings at the same time.

Dean: The GFS is moving back closer to the original track printed out by the model: now into the Caribbean, past "The Blade" and Cuba and into the Gulf. Regarding intensity...I'm concerned both the UKMET and the Euro (ECMWF) continue to barely keep Dean on life support...unlike the GFS model and the NHC "official" forecast calling for a fairly potent hurricane this weekend. Dean is still zipping along at a quick pace with no signs of a northwest component to his track, so the forecast will Hold The Line (great song by Toto!) and head toward the Lesser Antilles on a west or WSW track. From there, we must wait to see how the downstream players fit together. I have no changes to the various options laid out in previous blogs...I am rather confident the trof will set up just off the Eastern Seaboard, perhaps with a "cut off" Low. If Dean is tracking more to the northwest, let's say just north of Puerto Rico and the Dominican Republic, the storm probably heads northwest before the trof lifts and Ridging builds back in. I'd think Wilmington down to Florida would be at risk. If however, Dean stays on a west or WSW track, he misses the trof and if the storm avoids land masses (The Blade and Cuba), we have the potential for a large hurricane in the Gulf. Gulf hurricanes have nowhere to go, so Dean probably would make a US landfall "somewhere". We watch and wait.

Next update here at the blog on Wednesday morning.

Tropical Depression #4 and NEW Invest 91L...Possible Sneak Attack!
Monday, August 13

Invest 90L has officially become Tropical Depression #4 and is indeed forecast to become Hurricane Dean before reaching the Lesser Antilles on Friday. T.D. #4 should reach Tropical Storm status tonight or Tuesday morning. Get real-time information at our HurricaneCenter.

Current enhanced view (click graphic for more images):

INVEST 91L is the disturbance in the Caribbean. This system has developed Low Pressure at the surface and is moving to the Northwest...toward Texas. I am not sure if this Invest will become a Tropical Depression as wind shear will persist at least through Tuesday night. If shear slackens this could become T.D. #5 or even a weak Tropical Storm. Heavy rain and storms with isolated tornadoes from the northeast Mexican coast over to Louisiana can be expected.

Current enhanced view (click graphic for more images):

More on both storms later this afternoon.

UPDATE: 10:20PM:
Tropical Depression #4: Near pandemonium runs rampant tonight with hurricane enthusiasts and weather watchers as speculation mounts about TD #4's strength and track. Much of the hype surrounds a sudden shift in the US GFS model...taking "Dean" from Mexico to the Bahamas in six mere hours! This perceived flip-flop has many on the weather boards railing against the GFS model and so the "freak out forecasting" has begun.

Let's see where we are. The NHC has shifted the storm's track more to the northwest as seen in this graphic from Premium Service that I also posted on the S2K board this afternoon:

This slight shift is significant *only* if it holds, otherwise it's just a typical adjustment on a track more than 72 hours out. It is important to remember the TPC/NHC will be the first to say forecast tracks beyond 72 hours are subject to large errors (225 nautical miles on average), so before the panic starts in Florida, let's see what may be developing.

The GFS model is very bullish on TD #4; more so than the popular UKMET and ECMWF models. Subtle steering current changes have less affect on larger storms; this is why the GFS has shifted and the Euro has not...the Euro sees a much weaker cyclone. The other factors in this model's change are downstream: High Pressure Ridging over the Atlantic and a couple of trofs coming down into the Mid-Atlantic and Southeastern US (see yesterday evening's blog). There is also an Upper Level Low (ULL) north of the tropical cyclone that punches into the Ridge. It looks like the 18Z GFS run is pushing a sharp trof of Low Pressure further south and east than other models...this produces a weakness in the Ridge...a shoot, if you will, for the tropical cyclone to track into. The result is "Dean" comes around the Ridge and then gets pulled up toward the advancing trof. This solution brings a hurricane somewhere along the east coast of the US around August 21st.

This is NOT a done deal! This trof may advance and produce a slight weakness in the Ridge...but if the High Pressure dome expands inland, the storm would track northwest and then shift more to the west or WNW (this is how Andrew suddenly turned west after crossing 25° North). In this scenario, "Dean" may come up toward the Bahamas and before resuming a more westerly track. Cuba? The Keys? Florida? I don't know. But I do believe the tropical cyclone will begin a shift to the WNW on approach to the Lesser Antilles later this week.

Right now, the NHC forecast track skirts Antigua and Barbuda, but this likely will change over the next several days. Interests in the Caribbean must closely monitor T.D #4 as it fully is expected to become a hurricane. It must be noted the cyclone could also hold enough of a westerly component to eventually get near the Dominican Republic (aka The Blade) or even Jamaica.

You can get loopy micro analyzing every model run when it is more prudent to watch trends and see what consensus the models develop with synoptic weather ahead of the storm. That is what I will be doing as we start to get a better grip on this storm.

INVEST 91L: Hurricane Hunters fly in on Tuesday. This "blob" remains disorganized but shear will drop tomorrow and this could become Tropical Depression #5. The Invest is moving WNW into the western GOM and will produce moderate to heavy rain over South Texas.

Model maps on both systems are available in the Premium Service section of Mid-Atlantic WX.com.

Next update on Tuesday morning.

Invest 90L Could Become a Long Track "CV" Hurricane!
Sunday, August 12

I have been away for the last week at our local Boy Scout camp (VERY hot) and finally am back in the saddle...just in time for a potential tropical menace!

Here's this morning's models from our Premium Service hurricane model map section. NOTE: this map will NOT be current after 12 Noon today.

Convection is holding together nicely, circulation appears evident on the first daylight satellite images and there's even some signs of banding. My hunch is we will have a Tropical Depression tonight or Monday morning.

Most models do develop Invest 90L into a Tropical Depression...several bring it to a tropical storm or hurricane. As the National Hurricane Center frequently reminds us, storm intensity, particularly beyond 72 hours, is extremely unreliable. Regarding a possible track, the GFS model seems further south than anticipated steering currents but has remained consistent on bringing the tropical cyclone through the Caribbean and into the western Gulf of Mexico. It is far too early to speculate on a long range track, however, interests in the Lesser Antilles and Windward Islands certainly need to monitor this storm's development and track. The system currently is over five days away from the Islands. I will caution you that this storm does not automatically go into the GOM...storms tracking as depicted by the GFS sometime are called "western runners" and while possible, I'm not sold on this scenario. Another option is High Pressure bounces back after a departing trof of Low Pressure moves away...this could steer the storm toward the Southeast or Mid-Atlantic coast sometime after August 19.

This system, assuming it does develop, should stay south of "The Benchmark" I use as a tool in determining the threat a storm has to the US. Storms that pass to the south and west of the intersection of 20°N and 60°W have the greatest probability of a hit or near miss on the US. Not all...but most.

I'll have a more expanded look at this Invest tonight with an update here at the blog.

UPDATE: 9:25PM: Modest wind shear appears to have displaced convection west of the low level circulation (LLC) and it is possible the center will reform west of the current approximated position (12.7N|27.1W). Invest 90L has struggled but held together today, with a nice convective burst associated with colder cloud tops...often a precursor of strengthening. As such, I am bullish this becomes T.D. #4 in the next 24 hours...perhaps as early as 11PM tonight or 5AM Monday, although the NHC usually waits for a daylight satellite examination on distant storms so it may not be until 11AM or even 5PM on Monday. But
"04L NONAME" is coming..

Despite the EURO model totally dropping the cyclone earlier today, I believe we will have Tropical Storm Dean within 72 hours. There simply is no reliable way of predicting with any accuracy the ultimate path if a storm or hurricane does develop. In the medium range, this storm will likely scoot along on a nearly westbound track, which threatens the Lesser Antilles next Friday. This, in my opinion, is a reasonable concern at this time. Beyond that, it simply is too soon to forecast a western runner, a recurve into the central GOM or Florida...or a SEUS/Mid-Atlantic threat. Despite the obvious (will this become a hurricane on the anticipated forecast track?), other players are on the field. While the Central and Southern US bake under torrid temps, a trof is expected to dig down from Canada as the presumed tropical cyclone nears the Yucatan in about ten days. Does this pan out? How deep is the trof? Where is "Dean" in relation to the weakness? And then we consider High Pressure ridging over the western Atlantic...does that dome build in over the Mid-Atlantic and Southeastern US and Florida? If so, is the storm steered Northwest and recurves into the central Gulf of Mexico? Maybe the Ridge doesn't extend inland due to the trof coming down...does that option open the door to an East Coast hit or near miss? I have no idea...all are possible although I'm far from sold on a Florida/East Coast solution at this time.

As this is typed, the 0Z models are coming in and going online with our Premium Service hurricane model maps, there is excellent continuity and agreement the storm stays south of 20° North at least until 70° West (near the north coast of the Dominican Republic). From there, the fun and games begin with several options open for business. So, for now, we leave it as follows: Lesser Antilles must monitor likely development with interests in the Caribbean also keeping a close eye on any future track. Central America and Mexico grow concerned if the storm strengthens later this week while maintaining a western runner path. GOM and Florida, along with SEUS coast should focus attention later this week, especially if we have a growing hurricane in the central Atlantic.

Friends, this is when it gets interesting! Next update tomorrow here on the blog.

Invest 99L: The Thing That Wouldn't Leave...And...
Sneak Attack Update in the Gulf.
Friday, August 3

Remember the old Edwin Starr song titled "War"? Part of the chorus is: "Good God, Y'all. What is it good for? Absolutely nothing". This song, btw, was made famous again in an earlier Rush Hour movie, and I can't wait for RH3 to come out in one week!

This is the Invest 99L theme song...good for nothing and just won't go away. As suggested here and elsewhere, it is most unlikely this system will develop. This morning's view (note, this is not a "live" image. Click here for current enhanced satellite):

The elongated blob south of the Dominican Republic is Invest 99L. It appears the Invest has now lost all surface circulation and is approaching very dry air beneath 30 knot wind shear. Folks, Katrina probably wouldn't have survived this environment and Invest 99L will not. While convection has flared up again this morning, this is typical but shows no sign of circulation. Rather, the thing that wouldn't leave has opened to a tropical wave (linear, not circular) and is heading toward the Yucatan. Showers and rain expected for Jamaica, but no development. As an aside, the 6Z models did not initialize on Invest 99L this morning and we'll see if the 12Z models run this morning. Another sign the Fat Lady is warming up!

Meanwhile, if you read last Sunday's blog below you'll see we discussed the potential for a sneak attack in the NE Gulf of Mexico. This has developed but should move inland prior to anything spinning up. NHC comment this morning:

CLOUDINESS AND SHOWERS OVER THE NORTHEASTERN GULF OF MEXICO ASSOCIATED WITH A BROAD TROUGH OF LOW PRESSURE REMAIN DISORGANIZED. DEVELOPMENT...IF ANY...SHOULD BE SLOW TO OCCUR.

Click HERE for GOM close-up. I'm skeptical anything develops near Big Bend from this, however, so long as there is a boundary hanging around it will be monitored. The GFS model tries to develop Low Pressure well east of Myrtle Beach, SC next week while the CMC cranks a low off SC and spins it back toward Florida.
I don't know about this...maybe the models are thinking about the line from Detective Carter in an earlier Rush Hour movie: "Ah, I was just playin' wit ya...".

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