Tropical Tidbits from the Tundra

Invest 92L forms in the NW Caribbean

By: Levi32, 3:27 PM GMT on May 31, 2007

I was pretty sure this MJO pulse would come through eventually, and sure enough this morning 92L has emerged, by far the best organized tropical disturbance we've had this season, if you can all it a season yet lol. Technically it starts tomorrow, and that leaves only a short window for this thing to make history. If 92L can get named today, it will only be the second time in history that two named storms have formed in May. However I doubt this will happen. Our disturbance doesn't have a closed surface circulation yet, and remains for the most part poorly organized, although it does have some nice banding flowing into the mid-level center. An upper-level feature over the NW Gulf of Mexico is serving to ventilate the NW Caribbean, providing a nice divergent flow aloft. This pulls away air in the upper atmosphere faster than it is replaced at the surface, causing surface pressures to lower. Wind shear is moderate (10-20 knots), and it gets much higher as you go north. The disturbance will be sitting in the same area for 2-3 days, and shear is forecast to weaken some in its future path, which takes it north into the GOM.

All the models have been consistently forecasting this to develop for a few days now. The GFS, UKMET, and ECMWF all slowly develop 92L and take it north in 2 days across southern/central Florida, moving it off the Carolinas in 4 days. The CMC is the outlier in both track and intensity, taking 92L to a minimal hurricane and drilling it right into the bight of Florida. Currently I think the majority is more correct, and a positively tilted trough extending across Florida in 3 days should pull whatever's there with it NE across the Florida Peninsula. This is EXTREMELY good news for Floridians who desperately need rain. Considering that this should be no more than a 40-knot TS when it makes landfall, it will be a most welcome storm for the residents.

My thinking is that this develops a closed surface circulation today, and becomes a TD tomorrow, possibly getting named Barry by the end of the day. Depending on how the wind shear behaves, we could have a dissipating cluster of t-storms crossing Florida, or a TS Barry that will look very much like TS Alberto did last year when it crossed Florida. Remember how we thought it was dead when wind shear ripped it apart? New convection formed to the east and sucked in the COC just before landfall, intensifying Alberto to a strong TS. The same kind of setup could happen here, so we can't call the animal dead until it's dead lol. I will have more updates as the situation unfolds.

We shall see what happens!
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ NASA zoomed-in visible loop of 92L

Recon plan of the day for tomorrow


Model tracks for 92L

000
WONT41 KNHC 311549
DSAAT
SPECIAL TROPICAL DISTURBANCE STATEMENT
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
1150 AM EDT THU MAY 31 2007

SHOWERS AND THUNDERSTORMS IN THE NORTHWESTERN CARIBBEAN SEA...
SOUTHEASTERN GULF OF MEXICO AND ADJACENT LAND AREAS ARE ASSOCIATED
WITH A BROAD AREA OF LOW PRESSURE CENTERED ABOUT 75 MILES SOUTHEAST
OF COZUMEL MEXICO. ALTHOUGH THIS SYSTEM HAS SOME POTENTIAL FOR
TROPICAL DEVELOPMENT OVER THE NEXT DAY OR SO...THE LOW IS EXPECTED
TO MOVE SLOWLY NORTHWARD INTO THE SOUTHERN GULF OF MEXICO WHERE
ENVIRONMENTAL CONDITIONS WOULD LIKELY FAVOR FURTHER DEVELOPMENT AS
A NON-TROPICAL LOW. REGARDLESS OF DEVELOPMENT...THIS SYSTEM SHOULD
BRING HEAVY RAINS ACROSS WESTERN CUBA AND SOUTHERN FLORIDA OVER THE
NEXT COUPLE OF DAYS. PLEASE MONITOR PRODUCTS ISSUED BY YOUR LOCAL
WEATHER SERVICE OFFICE FOR MORE DETAILS.

ADDITIONAL INFORMATION ON THIS SYSTEM CAN BE FOUND IN HIGH SEAS
FORECASTS ISSUED BY THE NATIONAL WEATHER SERVICE... UNDER AWIPS
HEADER NFDHSFAT1 AND WMO HEADER FZNT01 KWBC.

$$
FORECASTER FRANKLIN/BLAKE/BROWN




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Updated: 6:07 PM GMT on May 31, 2007

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Caribbean development possible

By: Levi32, 4:23 PM GMT on May 26, 2007

Update 5pm:

The disturbance in the Caribbean has been labeled an invest per the SSD and they have a floater on it. The navy should have it up shortly.

Update Saturday 2pm:

The latest NHC discussion mentions possible LLC development with the Caribbean system.

GULF OF MEXICO...W ATLANTIC...AND THE NW CARIBBEAN...
A MIDDLE/UPPER LEVEL CYCLONIC CIRCULATION IS CENTERED OVER THE
FAR EASTERN GULF OF MEXICO NEAR 27N84W AND IS MOVING SLOWLY SW.
A TROUGH EXTENDS SW FROM THE CIRCULATION ACROSS THE E COAST OF
THE YUCATAN PENINSULA WITH CYCLONIC FLOW COVERING THE E HALF OF
THE GULF...THE NW CARIBBEAN...AND THE ATLANTIC W OF ABOUT 75W.
WATER VAPOR IMAGERY INDICATES STRONG SUBSIDENCE OVER THIS AREA.
BROAD RIDGING ALOFT COVERS THE WESTERN GULF WITH DIFLUENT FLOW
AIDING THE DEVELOPMENT OF THUNDERSTORMS OVER E TEXAS AND JUST
OFFSHORE OF THE LOWER HALF OF THE TEXAS COAST. AT THE SURFACE A
TROUGH EXTENDS FROM THE W TIP OF CUBA INTO CENTRAL HONDURAS.
VISIBLE IMAGERY INDICATES SOME CYCLONIC ROTATION AT THE LOWER
LEVELS AND A SMALL AREA OF MODERATE CONVECTION IS LOCATED NEAR
19N84W.

CENTRAL ATLANTIC AND THE REMAINDER OF THE CARIBBEAN SEA...
BROAD RIDGING COVERS THIS AREA WITH THE AXIS LOCATED FROM NEAR
29N62W ACROSS THE DOMINICAN REPUBLIC TO NEAR 12N78W. THE RIDGE
IS CAPPED BY A SUBTROPICAL JET WITH ITS AXIS EXTENDING FROM
CENTRAL CUBA TO 28N70W TO 30N55W. THE JET THEN TURNS NORTHWARD
BEYOND 32N49W. CLOUD DRIFT WINDS ARE AS HIGH AS 60 KNOTS ALONG
THE JET. STRONG THUNDERSTORMS EXTEND NORTHWARD FROM THE COLOMBIA
COAST TO 18N BETWEEN 72W AND 78W. A SURFACE LOW MAY FORM IN THE
VICINITY OF 12N78W OVER THE 24 HOURS. AT THE SURFACE A
STATIONARY FRONT EXTENDS THROUGH 32N51W TO 23N62W AND THEN
CONTINUES AS A TROUGH SW TO NEAR 20N70W. CONVECTIVE ACTIVITY IS
STRONGEST WITHIN 4 TO 5 DEGREES N OF THE TROUGH AND A LOW MAY
DEVELOP NEAR 25N70W WITHIN THE NEXT 24 HOURS.

You can see hints of a surface rotary circulation center developing in the lower-left corner of this loop, but the system remains poorly organized with all the convection off to the east. Also there is a conflicting mid-level center centered in the middle of the convection, but the low-level center is developing off to the west. This will probably set up a classic battle for domination between the centers if this disturbance survives the wind shear. Shear will be lessening throughout the next several days, and conditions will gradually become more favorable for development, so we will need to keep an eye on this.

Previous update Saturday morning:
The current pulse of upward motion in the western Caribbean has been setting off t-storms for days, but nothing quality has formed so far, and the first blob has exited into the eastern Pacific. However, this morning we have more convection firing up north of Panama and Columbia, with a slight mid-level spin to it. This is not all that much greater of a disturbance than the last one, but notice the wind shear map this morning:



During the last 2 weeks we've had 65+ knot values once you move to Cuba's latitude. Now those values are relaxing dramatically, with highest values only in the 50s as you go north. An area of 10-15 knot shear is moving into the SW Caribbean, and I think shear over the entire area will finally start to abate like the GFS has been forecasting for weeks. This will be the opportunity for something to get going in the SW Caribbean with this MJO pulse. SSTs are quite nice at 29c throughout much of the Caribbean, and once shear relaxes I think there will be a decent chance of seeing something try to
develop in there.

After backing off on the last system, the models are now hinting at development yet again from the afore-mentioned disturbance north of Columbia. The CMC, GFS, and NOGAPS all develop some sort of weak low and move it north near Florida during the next 4 days. The CMC was bombing it out off the Carolinas yesterday, but I don't buy it. However this is something that should be watched, and the window for development lasts until around June 10th, so there's plenty of time for something to try to get going.

The rest of the tropics are quiet, except for the very active ITCZ for this time of year. Enjoy it while you can! At least it's still May.

We shall see what happens!
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Updated: 9:08 PM GMT on May 26, 2007

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Watching the Caribbean

By: Levi32, 2:49 AM GMT on May 17, 2007

Wednesday Evening:

First of all I want to voice my thoughts on the Bahamas blob. This will NOT develop into a tropical depression because it will ride up the front into a baroclonic environment as an extratropical cyclone. However, this will be a very nasty May nor'easter for the New England states, with lots of flooding possible.

Now to the subject of my entry, which focuses on the Caribbean. The low forecasted by models to form today and tomorrow is just not going to form, and even if it does it will have no convection with it. Wind shear is just too high right now. However, during the course of the next two weeks, we are going to start seeing the shear go down over the entire tropical Atlantic, especially the western Caribbean. The MJO pulse will be moving into the Caribbean in 2 weeks, and we still have a mean trough positioning itself over the plains which will ventilate the western Caribbean by pulling air out at the upper levels which will lower surface pressures. The water is extremely warm for this time of year, even hotter than 2005. As I have voiced many times, I have great concern for major hurricanes in the NW Caribbean this year. No storm has touched those waters since Alberto of last year, which didn't even have an effect on the heat content since it was so weak. Also the European model jumped on board today forecasting a nice little tropical storm in the western Caribbean at day 10. Bottom line, keep an eye on that area for development middle-late of next week. Also keep in mind that the western Caribbean is climatologically favorable for most tropical cyclone developments in June.

In other news, La Nina is still alive and kicking with cold anomalies prevailing in the eastern Pac, and I still think a neutral-like to weak nina will prevail over the summer. Supporting factors are still not there for a strong episode, but we won't be seeing El Nino either.

There also continues to be no end in sight to the severe drought in the southeast US, especially Florida. The upper pattern set up right now just isn't sending any moisture their way. As a result fires continue to blaze all over the place, causing health hazards because of the smoke. Florida's only hope for precipitation this summer may come from tropical storms and hurricanes. In fact I believe Florida will be a big target for TCs this season. Depending on your view, this could be good or bad news. We certainly don't want any more major hurricanes rolling through, but the rain from a TS or Cat 1 would be more than welcome.

Keep your eyes open! There's a lot happening in the weather.

We shall see what happens!
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Andrea fights on

By: Levi32, 4:24 PM GMT on May 12, 2007

Saturday Morning:

If the last 3 days are any indication, we're in for a very weird hurricane season. After the NHC issued its last advisory on STS Andrea, she refuses to die off, and periodic bursts of convection keep forming. Andrea can't seem to hold on to convection for more than 12 hours straight before getting stripped again, but each time she looks more and more like a true tropical storm. This morning shows yet another burst, bigger than the others, and just when I thought she was dead last night she looks alive and well this morning lol. Wind shear is still below 10 knots in the area, and the environment is generally favorable for development with the exception of some dry air. The NHC has issued another tropical disturbance statement on the remants of Andrea just an hour ago:

000
WONT41 KNHC 121534
DSAAT
SPECIAL TROPICAL DISTURBANCE STATEMENT
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
1135 AM EDT SAT MAY 12 2007

A BROAD AREA OF LOW PRESSURE...THE REMNANT OF SUBTROPICAL STORM
ANDREA...IS CENTERED ABOUT 170 MILES EAST OF DAYTONA BEACH FLORIDA.
SATELLITE IMAGERY AND SURFACE OBSERVATIONS INDICATE THE SYSTEM HAS
BECOME BETTER ORGANIZED...AND IT COULD BECOME A TROPICAL DEPRESSION
DURING THE NEXT 24 HOURS AS IT MOVES SLOWLY TOWARD THE NORTHEAST.
AN AIR FORCE RESERVE RECONNAISSANCE MISSION THAT WAS SCHEDULED FOR
THIS AFTERNOON HAS BEEN CANCELED DUE TO RESOURCE ISSUES.

INTERESTS NEAR THE SOUTHEAST COAST OF THE UNITED STATES SHOULD
CONSULT PRODUCTS ISSUED BY LOCAL NATIONAL WEATHER SERVICE FORECAST
OFFICES. ADDITIONAL INFORMATION ON THIS SYSTEM CAN ALSO BE FOUND
IN HIGH SEAS FORECASTS ISSUED BY THE NATIONAL WEATHER SERVICE...
UNDER AWIPS HEADER NFDHSFAT1 AND WMO HEADER FZNT01 KWBC.

$$
FORECASTER BEVEN


What was Andrea will drift NE over the next few days, and whatever becomes of her she probably won't be affecting land again in her lifetime.

We shall see what happens!




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Melbourne, Florida radar loop

NASA High Resolution Visible Loop of Andrea

Water Vapor loop of Andrea

Latest Model runs for Andrea
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Tropical Disturbances:

None at this time, but the western Caribbean should be watched over the next couple weeks for possible activity as shear lowers and the ITCZ comes north. ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
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Updated: 4:31 PM GMT on May 12, 2007

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Andrea rises from the dead?

By: Levi32, 2:38 PM GMT on May 11, 2007

Will Andrea pull yet another surprise for us? After the NHC declared her a remnant low last night, Andrea doesn't seem to happy about it, and has decided to launch a comeback. A burst of thunderstorms has formed on the SE side of the center, and has been sustained for several hours now. This new burst is now making Andrea look like a true warm-core system for the first time, with the development of its first CDO. A comeback will still be extremely hard for this system with all the dry air around, but wind shear has dropped to 10 knots or less, and she still has a chance. Regardless of what she does, Andrea will meander around the same general area for the next couple days, before models predict her to be swept out to sea by a passing trough. If she reforms this could all change though, and Florida just might get another chance for rain out of this system.

We shall see what happens!




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Melbourne, Florida radar loop

NASA High Resolution Visible Loop of Andrea

Water Vapor loop of Andrea

Latest Model runs for Andrea
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Tropical Disturbances:

None at this time, but the western Caribbean should be watched over the next couple weeks for possible activity as shear lowers and the ITCZ comes north. ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
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Updated: 3:08 PM GMT on May 11, 2007

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Andrea weakening

By: Levi32, 2:09 PM GMT on May 10, 2007

Subtropical storm Andrea is weakening this morning, after providing a jolting start to the hurricane season. Andrea is nearly stationary east of Florida, and should meander around that area for another 48 hours before completely dissipating. Too bad she didn't get any rain into Florida. The ironic and sad thing is that, unlike most tropical storms, Andrea only fueled and intensified the fires over GA and FL. The strong, dry winds on the back side just fanned the flames, and no rain ever came. Andrea does have a weak warm core structure, but she will not be able to sustain herself unless she moves back where she was two days ago, which was over the gulf stream to the northeast. I expect a gradual turn and drift to the east-northeast will ensue, but she will probably dissipate before getting anywhere. Oh well, we had our fun lol. Hurricane season is here! Time to watch for Barry.

We shall see what happens!




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Latest public advisory from the NHC

Latest forecast discussion from the NHC


NASA High Resolution Visible Loop of Andrea

Water Vapor loop of Andrea

Latest Model runs for Andrea
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Tropical Disturbances:

None at this time, but the western Caribbean should be watched over the next couple weeks for possible activity as shear lowers and the ITCZ comes north. ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
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Updated: 2:27 PM GMT on May 10, 2007

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Subtropical storm Andrea!

By: Levi32, 2:48 PM GMT on May 09, 2007

This is it folks! Welcome in the 2007 hurricane season, because we have subtropical storm Andrea! As I predicted, the system has acquired enough subtropical characteristics to be named. In my opinion it still should have been named last night, but the NHC wanted to wait for this morning's recon, which has confirmed my suspicions. A tropical storm watch has been issued for the northern Florida coastline and parts of the Georgia coastline. The storm's convection still isn't all that deep this morning, but it is slowly intensifying with each passing day, and there is a strong band just to the southeast of the center. The storm is still moving slowly west, and I expect we will see a very close encounter with the southern Georgia/northern Florida coastline sometime in the next 48 hours. The track after that could be rather bizzare. The models have it going anywhere from inland up the east coat to going SE back into the Atlantic. Tropical Storms under big highs like this are very unpredictable, so we'll probably just have to play the long-term track by ear.

We shall see what happens!




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Latest public advisory from the NHC

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Phase Analysis Model Comparisions for SE low

NASA High Resolution Visible Loop of 90L

Water Vapor loop of 90L

Latest Model runs for 90L
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Tropical Disturbances:

None at this time, but the western Caribbean should be watched over the next couple weeks for possible activity as shear lowers and the ITCZ comes north. ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
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Updated: 3:13 PM GMT on May 09, 2007

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Invest 90L strengthens

By: Levi32, 7:58 PM GMT on May 08, 2007

Well the low off the SE coast has finally been labeled the first invest of the 2007 hurricane season. And about time too. The system continues to slowly move west, a landfall on the Georgia coastline could be coming up in the near future. On visible loop you can see the thunderstorms increasing in intensity and coverage. They are also forming fairly distinct bands now, which will start to wrap towards the center of circulation. The storm is now beginning to bear a striking resemblance to hurricane Ophelia of 2005, which moved over the same area as 90L, and had that "donut" look to it, with crude t-storm bands around the outside. The low is now moving over the heart of the gulf stream, which will aid in t-storm development over the center. Personally I don't like the look that 90L is throwing at us. It's becoming more organized by the hour, and if the dry air doesn't choke the thunderstorms, this will start looking like a tropical storm by tonight. Based on current data, I'm laying down a prediction that we will have subtropical storm Andrea at 11pm EDT tonight.

Now, the NHC may not even name this EVEN IF it is a STS. Why? Well as GetReal was saying in his blog the NHC won't want to hype the media and public into thinking this will be an early and active hurricane season. Personally I think that's dumb, and they should just forecast the weather and not worry about politics. For these reasons this storm may not get named until post-season analysis, but for my part, this thing will be a subtropical storm before it reaches the coast. Potential impacts remain rough surf, beach erosion, and high winds fanning fires over GA and FL. Hopefully if this thing comes inland it will have enough moisture to dump some rain, but right now it doesn't look like there will be enough t-storms to be able to sustain themselves over land. The future track beyond 90L's encounter with the coastline is still uncertain. It will either dissipate over land or move back out over the ocean and meander around for a while before fizzling out.

We shall see what happens!




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Phase Analysis Model Comparisions for SE low

NASA High Resolution Visible Loop of 90L

Water Vapor loop of 90L

Latest Model runs for 90L
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Tropical Disturbances:

None at this time, but the western Caribbean should be watched over the next couple weeks for possible activity as shear lowers and the ITCZ comes north. ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
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Updated: 8:10 PM GMT on May 08, 2007

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Subtropical Storm Andrea?

By: Levi32, 2:23 PM GMT on May 08, 2007

Tuesday Morning Update:

The NHC has finally brought this to the public's attention. They issued a special tropical disturbance statement at 9:50am EDT:

000
WONT41 KNHC 081346
DSAAT
SPECIAL TROPICAL DISTURBANCE STATEMENT
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
950 AM EDT TUE MAY 8 2007

A NON-TROPICAL LOW PRESSURE SYSTEM...CENTERED ABOUT 230 MILES
EAST-SOUTHEAST OF THE GEORGIA AND SOUTH CAROLINA COASTS...HAS BEEN
MOVING SLOWLY WESTWARD AT 5 TO 10 MPH. THIS SYSTEM IS PRODUCING
GALE-FORCE WINDS AND HEAVY SURF ALONG THE COASTS OF NORTH
CAROLINA...SOUTH CAROLINA...AND GEORGIA...WITH STRONGER WINDS
OFFSHORE. ASSOCIATED SHOWER ACTIVITY HAS INCREASED SINCE
YESTERDAY...BUT NO SIGNIFICANT STRENGTHENING OF THIS SYSTEM IS
EXPECTED. THE LOW IS BEING MONITORED FOR SIGNS OF TROPICAL OR
SUBTROPICAL CYCLONE DEVELOPMENT...AND AN AIR FORCE RESERVE
RECONNAISSANCE AIRCRAFT WILL BE AVAILABLE TO INVESTIGATE THE SYSTEM
TOMORROW MORNING...IF NECESSARY.

INTERESTS ALONG THE COAST OF THE SOUTHEASTERN UNITED STATES SHOULD
MONITOR PRODUCTS ISSUED BY LOCAL NATIONAL WEATHER SERVICE FORECAST
OFFICES. ADDITIONAL INFORMATION ON THIS SYSTEM CAN ALSO BE FOUND
IN HIGH SEAS FORECASTS ISSUED BY THE NATIONAL WEATHER
SERVICE...UNDER AWIPS HEADER NFDHSFAT1 AND WMO HEADER FZNT01 KWBC.


$$
FORECASTER KNABB


It will be very interesting to see what that recon finds if it goes in there tomorrow. So how is our little low doing this morning? Well convection isn't all that much deeper, but it has increased slightly in coverage over the center, and the low has all but lost its fronts. What little convection there is is continuing to warm the center, and if I were the NHC I'd be calling it subtropical along with the rest of the weather branches. The models give it between 24-48 hours over water before most of them move it ashore between Melbourne, Florida and Charleston, SC. This will be a tight window for this thing to ramp up if it wants to. It's just now starting to move over the warm waters of the gulf stream, and wind shear is surprisingly low. Instead of the usual unsymmetrical storm with all the convection to the east side, we have a symmetrical system with convection spread out across the whole circulation. This is a good thing not only for the storm itself, but for the Floridians, who just might get some rain from the storms in the SW quadrant of the storm. I think whether or not this becomes a STS will all come down to when it runs out of real estate. The ingredients are there, it just needs time to work with them. Now I do think there is a possibility of this becoming STS Andrea tomorrow. Why am I skipping the depression stage? Because, the winds in the entire system have exceeded depression threshold ever since it formed. The buoy on the very outskirts of the system is still reporting sustained tropical storm force winds. So if the NHC names it, it will be Andrea, not subtropical depression #1.

We shall see what happens!

Phase Analysis Model Comparisions for SE low

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Updated: 2:24 PM GMT on May 08, 2007

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Low off SE coast

By: Levi32, 2:45 PM GMT on May 07, 2007

Monday Evening Update:

Little change tonight. Models are doing the same thing as before. I'm quite impressed at how consistent they are. The low off the NC coast is raising a lot of questions about its future as expected. Convection has wrapped around the center since this morning, but it's still cold-core. The convection is not very deep at all, and doesn't seem to be forming by tropical processes yet. However, the fact that convection is forming over the center of circulation at all means that the transition to warm-core has already begun. The t-storms are releasing latent heat into the center of the storm, which will eventually become warmer than the outsides of the system. By tomorrow it should lose its fronts, and we'll have to see what the convection does. The storm is so large that it's bringing in a lot of dry continental air, which will make it very difficult for deep convection to get going. As for track my ideas are the same as the last update. Models are in good agreement on a southwest drift for the next 2-3 days. Beyond that the low could make landfall anywhere from Florida to Cape Hatteras, or stay offshore altogether.

Strong winds bringing dry air into Georgia and Florida will enhance wildfire activity, which is definitely not good news for those areas. The storm may get a chance to redeem itself if it moves over Florida and dumps some rain. The winds will also cause rough surf for ships in the vicinity, as well as causing moderate beach erosion across the southeast. The peak of its winds has passed (unless it becomes a hurricane later lol), and the gradient will continue to weaken tonight and tomorrow as the low gets detached from the front to the north. I remain adamant that this will be our first invest, but neither the navy or the NHC has given any thought to it yet apparently. The Satellite Services Devision has though, and has unofficially labeled it 90L after the low made sub-tropical Dvorak classifications late last night. Depending on how tonight's diurnal max affects convection into tomorrow morning, I think we will see some more steps taken toward the system converting to warm-core, and if the NHC knows anything they'll label it an invest. It's already more tropical-like than the first invest we had last year. Right now it's just watch and wait. Nothing major to worry about, just really interesting.

We shall see what happens!

Previous Update:
Well, now the models will be put to the test. Were they right? A 998mb low has formed SE of Cape Hatteras, and is currently moving southwest. The storm is obviously cold-core, but the conversion to sub-tropical will begin right away. This is almost a given for me now. Why? Three reasons. One, this thing will completely lose its fronts by tomorrow and become symmetrical. Two, this is a very tightly-wound storm already. Check out this bouy reading 150 miles east of Cape Hatteras this morning:

05 07 12:50 am NE 54.4 69.9 35.8 13 10.3 - 29.64 -0.12 59.9 67.3 59.5

That was winds from the NE at 60mph SUSTAINED with gusts to 80. Pretty tight gradient out there. The surface map even has the low labeled at hurricane force already. My third reason for thinking that this thing will turn warm-core is that it is moving SW, over warmer and warmer water. The fact that it's moving SW at all is evidence enough, but the warmer SSTs in the gulf stream will help it a lot. Models are still divided on this. The GFS kind of takes it ashore and dissipates it by 120 hours. The CMC doesn't know what to do with it, taking it over South Carolina and then back over the Atlantic again through the end of the model run. The NOGAPS is interesting, it takes the low right across central Florida and into the eastern Gulf of Mexico. By the end of the model run the low is all but dissipated, but by that time it was in the NW Caribbean, which is slightly intriguing. The UKMET follows the NOGAPS across Florida, but much slower, and dissipates the system before it can get into the eastern GOM.

I don't really know which solution to side with here. Systems trapped under a high like this are extremely unpredictable. Remember hurricane Jeane in 2004 when it did loopty loops around the Bahamas before deciding on a track. My general idea is closer to the UKMET solution. I think the low will continue to drift SW, and a run-in with Florida is possible. One thing that's clear now is that the low is not a fish storm. The troughs to the north won't pick it up because the heat from this upper high is blasting into New England pushing any trough well out to sea before it has a chance to deepen. I still think this goes warm-core, and we will see our first tropical invest out of it. A sub-tropical/tropical depression isn't out of the question either.

Whether this becomes tropical or not, the affects of this storm will mainly be felt through winds and high surf on the SE coast. The high winds from the north on the Florida Peninsula won't be good for the fires in the area. Hopefully the system will come over the state and provide some much-needed rain.

We shall see what happens!

Phase Analysis Model Comparisions for SE low

Atlantic Models

Nasa Zoom-in Satellite Page

SSD tropical formation probability and other maps

CIMSS satellite derived winds and analysis

National Hurricane Center





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Updated: 3:19 AM GMT on May 08, 2007

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Disturbance off the SE coast

By: Levi32, 5:42 PM GMT on May 06, 2007

Sunday Morning:

Not much is changed from yesterday. The disturbance is beginning to form off the SC coast, and a surface circulation should become defined later today. Models are for the most part unchanged. The GFS has shifted west though, and now brings the low ashore in South Carolina instead of tossing it out to sea. The UKMET, Euro, and NOGAPS all continue to bring the low south towards the east coast of Florida, which is tickling their desire for rain, which hopefully they might get. I am going with the low looping around to the south and eventually getting kicked out into the open Atlantic.

So will it become tropical? Well I have mixed feelings about this. Most of the models are forecasting it to become at least sub-tropical, and the NAM completely converts it into a tropical hurricane. Now I don't think this will become a hurricane, but I do think we will see the first invest of the season out of this, and a sub-tropical depression is likely. Whether or not it becomes fully tropical will depend on many things. The SSTs in the area are at only 25C, with the exception of the gulf stream. The position of the low in relation to the gulf stream will be key. The low will be meandering in the same area for 4-5 days. If it can get enough time over the gulf stream, it might help it convert to warm-core. Wind shear could be a problem, since pockets of moderate shear (25-30 knots) will be moving through the area periodically over the next few days. Otherwise, we basically have a decent setup for our first tropical disturbance. An anticyclone will be positioned over the top of the system, and with all the time it's got anything can happen. The most we can hope from this storm is to provide some much-needed rain for Florida.

We shall see what happens!

Phase Analysis Model Comparisions for SE low

Atlantic Models

Nasa Zoom-in Satellite Page

SSD tropical formation probability and other maps

CIMSS satellite derived winds and analysis

National Hurricane Center





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Updated: 2:44 PM GMT on May 07, 2007

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Sub-tropical development likely off SE coast

By: Levi32, 2:11 AM GMT on May 06, 2007

Saturday Evening:

The latest model runs continue to strongly indicate tropical or sub-tropical formation off the Carolinas in 24-48 hours. As of yet the low hasn't showed up, but I see signs of cyclogenesis off of the SC coast. Model solutions remain about the same as the morning runs, with the UKMET, Euro, and NOGAPS as the southerly outliers, taking the low south towards Florida before kicking it out, and the GFS and CMC as the northerly models. While Floridians may give up hope of getting rain out of this system, it's potential track could lead almost anywhere, and it is way too early to start fiddling with where it will go. The more pressing matter right now is will it acquire tropical characteristics. Well the models seem to think so. All the models turn the low warm-core, and the NAM is extremely bullish, turning it totally tropical and intensifying it into a hurricane. I think this solution should be viewed with skepticism until proven otherwise. A hurricane in that environment is highly unlikely, given the cool SSTs and moderate wind shear. Granted, storms have formed in these conditions before (Epsilon, Zeta, to name a few), but you don't see that every day. My thoughts for now are that this will become the first invest of the season, and there is a strong possibility of it becoming a tropical/sub-tropical depression or storm.

We shall see what happens!

Atlantic Models

Nasa Zoom-in Satellite Page




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Updated: 5:01 PM GMT on May 06, 2007

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Possible rogue storm off the SE coast

By: Levi32, 6:11 PM GMT on May 05, 2007

Well, here we go! This is my first post of the 2007 hurricane season relating to tropical development. Models are forecasting a low to form off the Carolinas on Monday. The models are in general agreement on intensity, forecasting a central pressure in the upper 990s, but diverge on the track. The CMC and GFS keep the low near the Carolinas for several days, and then eventually kick it out. The European, UKMET, and NOGAPS all take it south off the Florida east coast, and leave it sitting there and weakening throughout the model run.

Personally I'm siding more with the UKMET's solution, which meanders the low south off of Florida, and then the low drifts NE, eventually being picked up out to sea. The low has the potential to develop tropical or sub-tropical characteristics as it sits off the southeast coast for 4-5 days. The possibility for getting it named is remote, however, due to SSTs being only 25c and wind shear won't be that favorable either. I think we have a good chance to get our first invest out of this, but I'm not sold on any tropical system forming yet. We'll see how it goes, at least we finally have something to watch! :)

We shall see what happens!

Atlantic Models

Nasa Zoom-in Satellite Page




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About Levi32

Levi Cowan has been tracking tropical systems since 2002, and is currently working on his bachelor's degree in physics at UAF.

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