Invest 94L was upgraded to TD9 early this morning. Recon flies in early this afternoon. If the forecast model tracks verify, things could be getting interesting for FLA in 7 days time. It's held up pretty well against dry air and is moving into warmer sea-surface temps and little to no shear.

FORECAST POSITIONS AND MAX WINDS
INIT 21/1500Z 15.1N 52.8W 30 KT 35 MPH
12H 22/0000Z 15.2N 55.3W 35 KT 40 MPH
24H 22/1200Z 15.5N 58.4W 40 KT 45 MPH
36H 23/0000Z 15.9N 61.5W 50 KT 60 MPH
48H 23/1200Z 16.2N 64.6W 65 KT 75 MPH
72H 24/1200Z 17.0N 70.0W 80 KT 90 MPH
96H 25/1200Z 18.5N 74.0W 90 KT 105 MPH...INLAND
120H 26/1200Z 20.5N 77.5W 85 KT 100 MPH...OVER WATER

I will laugh my ass off if this is God's retribution for the RNC.

You read my mind, Gen.

Incidentally there has been no modern storm (and none that I can find any sort of accurate historical record for either) that plays the nightmare scenario for Tampa -- right up the bay.

A number of years ago when Charlie and friends were ****ing around I ran some numerical models on that and my best guess was that a Cat 3 coming up just west of Tampa Bay (worst-case scenario; east side of the eyewall coming into the bay) had the potential to generate twenty-plus foot surge into downtown, which puts the entire downtown Tampa area under 10+' of water.

And that's a Cat 3; it could easily be worse than that, but once the entire first floor of every building in the downtown area is underwater does it really matter all that much?

Doesn't Cuba pretty much guarantee a storm loses a lot of punch as it approaches Tampa?

a nuke plant that side of the state...wonder what the elevations are?

crystal river florida...seems kinda low

Mrbill, depends on what part of Cuba the center of the storm traverses and how fast it's moving. A slow-moving storm over mountainous terrain can lose significant punch. But the intensity forecast is for it to exit Cuba with 100mph winds.

GFS please.

GFS 7 days out - Karl's scenario possibly coming to fruition? Although it IS 7 days out, and lots of variables are still in play.

Recon's approaching TD9 now, so we'll have better info once they get an exact fix on the center and central pressure.

Canadian 7 days out - Eastern Seaboard...

Euro slows it down a bit - 10 days out:

There's a VERY high probability this one ****s SOMEONE in the US.

I forsee some long nights of wobble-watching in my near future...

Posted by: Dr. Jeff Masters, 10:54 AM AST on August 21, 2012

Tropical Depression Nine has formed in the waters a day's journey from the Lesser Antilles Islands, and is headed west towards the islands at 20 mph. This storm could be trouble for much of the Caribbean, and may affect the mainland U.S. next week. TD 9 is under light wind shear of 5 - 10 knots, and is over waters of 28°C. A large area of dry air lies just to the north, as seen on the latest Saharan Air Layer (SAL) analysis and water vapor satellite loops. This dry air is interfering with development, and will keep development slow today. This morning's visible satellite loops show that TD 9's heavy thunderstorm activity is limited on the north side, due to the dry air. TD 9 has yet to develop a good upper level outflow channel, which will also keep development slow today. An analysis of upper level winds from the University of Wisconsin CIMSS shows that the winds at high levels are blowing fairly uniformly from the east over the storm, and these winds would have to take on a more counter-clockwise pattern over TD 9 to produce the most efficient upper-level outflow. The clump of heavy thunderstorms to the southeast of TD 9 is also a limiting factor; this clump of heavy thunderstorms is competing for moisture and interfering with the low level inflow and upper level outflow of the storm. However, if TD 9 manages to wrap in this extra clump of heavy thunderstorms and add their spin to its own spin, it could become a very large and dangerous storm. Heavy thunderstorms are now attempting to fire up around TD 9's circulation center, but this is being hampered by dry air. The center of TD 9 passed about 20 miles to the north of buoy 41040 at 10 am this Tuesday morning. The buoy recorded top winds of just 18 mph this morning, suggesting that this is not yet Tropical Storm Isaac. The first hurricane hunter mission into TD 9 is scheduled for Tuesday afternoon.


Intensity forecast for TD 9

The latest 8 am EDT run of the SHIPS model predicts that wind shear will be low to moderate, 5 - 15 knots, for the next five days. Ocean temperatures will warm from 28°C this morning to 29°C by Wednesday afternoon, and the total heat content of the ocean will increase sharply during that period. The low wind shear and warm waters will favor strengthening. The main impediment to development through Wednesday will be dry air to the north, though the storm will also have trouble separating from the clump of thunderstorms to its southeast. I expect that TD 9 will continue to struggle with dry air through Wednesday. The official NHC forecast of a 60 mph tropical storm moving through the Lesser Antilles on Wednesday afternoon is on the aggressive side, and I put the most likely range of strengths for TD 9 Wednesday afternoon at 45 - 60 mph. Once TD 9 enters the Eastern Caribbean, wind shear will be low, oceanic heat content high, and the storm should have had enough time to moisten the atmosphere to allow steady strengthening to a hurricane. Intensity forecasts 4 - 5 days out are low in skill, though, and it would not be a surprise at all to see TD 9 struggle like so many other storms have over the past two years, and remain a tropical storm over the next five days. Conversely, rapid intensification into a Category 2 hurricane five days from now, as the official NHC and HWRF model forecasts are suggesting may happen, would also not be a surprise.

Impact of TD 9 on the Islands

The entire Lesser Antilles Islands chain will have a three-day period of heavy weather Wednesday through Friday, as TD 9 and the associated area of heavy thunderstorms to its southeast passes through. Sustained tropical storm-force winds of 40 - 60 mph will occur in the islands only on Wednesday, with Guadaloupe, Antigua and Barbuda, Martinique, Dominica, Montserrat, and St. Kitts and Nevis at highest risk of these winds.

TD 9 will make its closest approach to the Virgin Islands and Puerto Rico on Thursday, and heavy rains from the storm will affect these islands Thursday through Saturday. Tropical storm-force winds should remain just south of these islands.

On Thursday night, heavy rains and tropical storm-force winds should arrive on the southern coast of the Dominican Republic. If the center of TD 9 remains offshore, as appears likely, heavy rains from TD 9 will still be a danger to the country. Rainfall amounts of 4 - 8 inches will likely affect the Dominican Republic Thursday through Saturday, creating flash floods and mudslides. We can't rule out a direct hit on the Dominican Republic on Thursday evening or Friday morning, since the country is well within the NHC cone of uncertainty.

TD 9 is potentially a very dangerous storm for Haiti, where 400,000 people still live outside underneath tarps in the wake of the 2010 earthquake. Heavy rains from TD 9 will begin on Friday morning in Haiti, and last through Sunday. Rainfall amounts of 5 - 10 inches are possible, which will be capable to causing extreme flooding on the vegetation-denuded slopes of Haiti.

Longer-range outlook for TD 9

Heavy rains from TD 9 will begin in Jamaica and eastern Cuba on Friday night, but our vision of where the storm might be headed after Friday gets blurry. The official NHC track forecast at long ranges is heavily weighted towards the GFS and ECMWF models, which have done the best job predicting TD 9's path so far. In general, the models have been predicting a track too far to the north for TD 9, and I expect the storm will remain south of Hispaniola, avoiding the disruptive impact of that island's high mountains. While the current NHC forecast has TD 9 hitting Cuba just north of Jamaica five days from now, keep in mind that the average error in a 5-day forecast is 260 miles. Given the tendency of the models to predict a track too far to the north for this storm, and this season's general steering pattern that has already taken two storms into Mexico's Yucatan Peninsula, we should not be surprised if TD 9 takes a more southerly path than the official NHC forecast, and potentially become a threat to western Cuba or Mexico's Yucatan Peninsula. A trough of low pressure capable of pulling TD 9 to the north enters Western Canada Thursday, and the exact timing and amplitude of this trough as it crosses the U.S. this weekend will determine the ultimate landfall location of TD 9. The ECMWF model has a more northwards position for the trough, and thus keeps TD 9 moving more slowly and father south than the GFS. Both of these models predict an eventual landfall for TD 9 over Florida, and TD 9 is a threat to affect Tampa during the Republican National Convention, August 27 - 30. I blogged about the climatological chances of a hurricane causing an evacuation of Tampa during the convention in a post last week, putting the odds at 0.2%. The odds in the current situation are higher, somewhere in the 1% - 3% range. It would take a "perfect storm" sort of conditions to all fall in place to bring TD 9 to the doorstep of Tampa as a hurricane during the convention, but that is one of the possibilities the models have been suggesting could happen.

Looks like recon's now at operational altitude...

Landshark...I am running chrome and those images are not coming up...wtf?

Weird, Ulster - no idea why...

Minimum pressure so far 1007.6 Mb.

Make that 1005.4 mb...

Max surface winds oberved at 40.5 MPH... tropical storm strength. If that verifies on the next pass or two we could see an upgrade pretty quick.

46 MPH on that pass. Minimum surface pressure 1007.2 mb.

We're getting there.