Tropical Depression TEN: Discussions & Images

[Nimbus]

The center off the east coast near 28N will have to travel over land so it will probably be the the surface low off the west coast near 25N that becomes dominant. Once the models get this initialized correctly Texas will probably be the target. Hybrid system with the LLC working its way to the surface will take an extra day to develop.

AFM has been talking about that scenario for a few days now and I think the pro met consensus was that a Texas hit would be bad news since it would give Jerry enough time to reach hurricane strenth.

[Wx_Warrior]

The low forming further south: IE west of Ft Myers, would target Texas. I don't think the L near Melbourne dominates anything. Im sticking with the L near FTM.

[duris]

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NEW ORLEANS LA
314 PM CDT WED SEP 19 2007

.DISCUSSION...
FIRST 48 HOURS OF OUR FORECAST WILL BE TRANQUIL COMPARED TO THIS
WEEKEND. WITH THE STRONG UPPER LEVEL LOW OVER FLORIDA AND SURFACE
RIDGE FROM MID SOUTH TO NORTHWEST GULF...NORTHEAST WINDS WILL
MAINTAIN RELATIVELY DRY AT ALL LEVELS OVER THE FORECAST AREA
THROUGH THURSDAY AFTERNOON. THICKNESS VALUES FROM 1000 TO 700MB
SHOULD REMAIN AROUND 3030M THROUGH TONIGHT AND SURFACE TEMPS WILL
REFLECT THIS TREND FOR MOST AREAS. HOWEVER...NNE WINDS OF 10 TO 15
KNOTS ACROSS THE TIDAL LAKES WILL NOT DECOUPLE AND SHOULD CAPTURE
LAKE TEMPS OVERNIGHT ACROSS NEW ORLEANS. GFS IS A LITTLE FASTER THAN NAM
WITH THE MOISTURE FIELD INVADING EAST ZONES THURSDAY NIGHT. IN
ADDITION...THERE ARE SOME DIFFERENCES IN LOCATION OF THE
ASSOCIATED SURFACE LOW AND ESPECIALLY THE TRACK ACROSS THE GULF. NAM
IS SLOWER AND FARTHER NORTH THAN GFS. THE GREATEST SURFACE
PRESSURE FALLS WERE NOTED FROM NAPLES TO OFF THE COAST OF DAYTONA
BEACH. GFS AND NAM SHOWED THIS INITIAL DEVELOPMENT OF TWO LOWS
WITH THE SOUTHWEST LOW BECOME THE PREDOMINANT LOW THURSDAY
MORNING. ACCORDING TO TROPICAL CYCLONE HEAT POTENTIAL OF
AOML...THE WARMEST WATERS IN THE GULF WERE LOCATED OFF OF
SOUTHWEST FLORIDA AND CENTRAL GULF. ALOFT...MINUS 9C WAS NOTED AT
12Z TAMPA AND KEY WEST. GFS...NAM AND EUROPEAN INITIALIZED THIS
FIELD WELL. ALL DAMPEN THE COLD CORE BY THURSDAY AFTERNOON AND
SOME INDICATION OF A SUB-TROPICAL SYSTEM BECOMING TROPICAL. WITH
SOME MUCH DRY AIR ENTRAINMENT...IT WILL BE DIFFICULT TO PLACE THE
HEAVIEST RAINFALL RIGHT OR LEFT OF AN UNCERTAIN TRACK AT THIS
TIME...SO WILL LEAVES POPS AS IS. WE ARE MORE CERTAIN THAT
NORTHEAST TO SOUTHEAST WINDS CONTINUING AND INCREASING TOWARD THE WEEKEND WILL
CAUSE COASTAL FLOODING FRIDAY THROUGH SUNDAY. DEPENDING ON TRACK
OF THE CENTER OF CIRCULATION...EASTWARD AND/OR SOUTHWARD FACING
SHORELINES MAY EXPERIENCE THIS PROBLEM. MAY HAVE TO CONSIDER A
COASTAL FLOOD WATCH IN LATER PACKAGES. WILL MAINTAIN NORMAL RAIN
CHANCES NEXT MONDAY THROUGH WEDNESDAY.

[Sanibel]

Looks like a spiral center forming off Canaveral.

Sunny and warm here with scattered disturbed fair weather clouds.

[stormchazer]

I do not think that you can assume that a system that has not even been initialized is going to hit Texas. I would think the Gulf Coast west of the Panhandle should keep an eye.

[miamicanes177]

From Jeff Masters: Sorry if posted already

Recent Satellite loops and the Tampa Bay long range radar show that a non-tropical low pressure system (93L) appears to be reforming off the southwest coast of Florida. This is an important shift, since it brings the surface low underneath the upper level low pressure system aloft--the same kind of situation one finds in ordinary non-tropical "cutoff lows". This is an unusual event in September over the Gulf of Mexico, and is good news for those potentially living in the path of 93L. A surface low pressure system vertically aligned with a cold-cored upper level low will usually take a day or two to make the transition to a warm-cored tropical storm. During this kind of transition, rapid strengthening is rare, and the chances of 93L ever reaching hurricane strength now appear dim. The latest (12Z, 8am EDT) intensity forecasts from the GFDL and HWRF computer models keep keep 93L below hurricane strength, as does the 18Z (2pm EDT) SHIPS intensity model. The HWRF model indicates that 93L will come ashore at tropical depression strength, and this is entirely possible.

The forecast tracks from the latest cycle of model runs all show a landfall between central Louisiana and Pensacola, Florida on Saturday morning. The exceptions are the NOGAPS and ECMWF models, which show a Sunday morning landfall near the Texas/Louisiana border.

This is fantastic news from Dr. Masters. I was concerned this could be a hurricane but apparently the Dr. is convinced we have nothing to worry about.

[Derek Ortt]

http://www.pnj.com/blogs/weather/index.shtml

my latest thoughts on the system

[eaglegirl]

Ok, here is my take, FWIW.

Look at the 24 hour GFS from 12Z this morning:

http://www.nco.ncep.noaa.gov/pmb/nwprod ... n_024l.gif

Notice the glob of precip off the Carolinas- that nice slug of moisture that seems to be coming north as energy at the surface with our low near Cape Canaveral.

Now notice the low west of Naples in the GOM.

My belief is that any low over the Atlantic will move north or at least its energy will and bring some rain to the coastal Carolinas and maybe GA.

The upper low is obviously becoming more tropical with time. Why? When is the last time you could see an upper level low SO CLEARLY on visible satellite imagery? Plus, the UL is not moving much anymore- and is working over nice and warm waters.

Bottom line- the two pieces of energy spearate- one goes in to the Carolina offshore waters and the other becomes TD10 later tomorrow and heads generally W-WNW as it gets better organized.

Makes sense to me at this point considering the data that is available now.

Hurricanetrack (or anyone else with an opinion),

Just wondering...

Are you suggesting that we may end up with 2 systems simultaneously?

If so, do you think that both of them could be significant players?

Thanks in advance

[MWatkins]

Interestingly the TAFB and SAB center fixes were almost identical up at 28.5 and 80.1/2

This is a VERY complex weather system. With so much going on...it's hard to believe anything is going to consolidate in the short term. Again, however, tomorrow is development day (if it happens).

The idea that this could become a hurricane was predicated on the surface feature gaining some distance from the upper low...not the upper low becomming the surface feature.

Also, if that does happen, there is a dry wrap around 3/4ths of the circulation...and it is nice and dry here in SE Florida today. Dry air intrusion will be an issue.

Finally, the coupled GFDL keeps this as a relatively strong system well inland (after a LA landfall)...which to me suggests there is some baroclinic component to the projected intensity (as opposed to strict tropical develpment).

MW

[Stormcenter]

http://www.pnj.com/blogs/weather/index.shtml

my latest thoughts on the system

Good post and thank you.

[carversteve]

May be a dumb question..but is that not a spin i see off the west coast of florida

[jhamps10]

looks like we have more convection forming on our GOM potential LLC near the center



My vote goes for this in the GOM being the final LLC/ potential jerry.

[crownweather]

I have to agree with the European and GFS ensemble models and am going with a landfall on the upper Texas coast on Sunday morning. Although, even though this system could be translating from a cold-cored upper-level low to a warm cored system and it will take an extra day to do so....it will still have 72 hours over the Gulf of Mexico, therefore, I think landfall intensity could be between 85 and 100 mph.

[Sanibel]

Poleward centers tend to grab don't they? That is, when two centers vie for dominance in a weak system the poleward one has favor due to the poleward tendency of storms.

[Ed Mahmoud]

Also, if that does happen, there is a dry wrap around 3/4ths of the circulation...and it is nice and dry here in SE Florida today. Dry air intrusion will be an issue.

Anyone ever seen such a dry sounding anywhere in Florida in September???




Tallahasee.

[Ed Mahmoud]

May be a dumb question..but is that not a spin i see off the west coast of florida

Well, there is a big ULL, although I did find light West winds and pressures around 1009 mb at the buoys around the Keys.

[oyster_reef]

Looking at the visible loop and the convection that is building in off the SW coast I wouldn't be surprised to see this upgraded to TD by 11pm tonight. Key West is already telling us there is a surface west wind.

[carversteve]

May be a dumb question..but is that not a spin i see off the west coast of florida

Well, there is a big ULL, although I did find light West winds and pressures around 1009 mb at the buoys around the Keys.

It just looks to me like we have more spin there in the gulf just off the coast than anywhere else..comments please

[Air Force Met]

The low forming further south: IE west of Ft Myers, would target Texas. I don't think the L near Melbourne dominates anything. Im sticking with the L near FTM.

The low over south FL has shown up pretty clearly in the wind field over the last couple of hours. This one will be the dominant one and this means a hit further west. Also verifies what the EURO has shown...a low in the Keys by 00z tonight.

http://www.rap.ucar.edu/weather/surface ... duration=0

[Ed Mahmoud]

Looking at the visible loop and the convection that is building in off the SW coast I wouldn't be surprised to see this upgraded to TD by 11pm tonight. Key West is already telling us there is a surface west wind.

Nah. Why upgrade something that isn't certain, and is 48 hours from land, at least, when the AC will be there in the early afternoon. I suppose if it was as obvious as all get out, based on ships, buoys and vis satellite, they might pull the trigger on an STD at 10:45 AM EDT before the AC arrives.

Just my opinion.


Edit- changed "morning" to early afternoon. I better check the recon schedule again, but it seems like 1800Z is the popular time for recons for invests.