Hurricane Isaac

[phw115wvwx]

The amount of land this tropical storm encounters in the next several days will determine everything here from intensity to impacts in the United States.  Before you all go wild in predicting landfalls in the United States, keep in mind how many tropical cyclones have been torn apart by the high mountains in Cuba, Haiti, and the Dominican Republic in previous years.  I'm holding off my thoughts until I see better model consensus as I want to note how Isaac navigates through the Caribbean.  Also, the current forward speed of 20 mph is too fast to allow good intensification.

[toxictwister00]

The amount of land this tropical storm encounters in the next several days will determine everything here from intensity to impacts in the United States.  Before you all go wild in predicting landfalls in the United States, keep in mind how many tropical cyclones have been torn apart by the high mountains in Cuba, Haiti, and the Dominican Republic in previous years.  I'm holding off my thoughts until I see better model consensus as I want to note how Irene navigates through the Caribbean.  Also, the current forward speed of 20 mph is too fast to allow good intensification.

I don't know how true this is, but I've heard large, broad, unorganized systems tend to keep their mid level circulation in tact better than small, tight core developed systems when going over high elevated areas such as Cuba and Haiti.

Anyway, this is my second forecast, shifted slightly to the left/west. (Still in between the GFS/ECMWF)

[Localonthe8s]

Isaac will be an interesting storm to track

[toxictwister00]

Looks like the 0z GFS/ECMWF are more in line with my landfall track. GFS is only slightly east by a hair and the ECMWF is slightly west. The key thing here is both models are getting closer and closer to a consensus!

EDIT: Updated intensities, my track remains the same.

[Donovan]

Nice job on the track Tavores! It's a bit too early to tell, but I think we may get some TD or  TS impacts here in SC from this system in the Monday-Wednesday timeframe. GFS (normal) takes the system's central pressure just offshore of Charleston/Savannah after crossing FL/GA on Sunday/Monday. Local NWS office has included in an HWO the chance for Tropical Storm conditions here, which was a bit shocking. Also on an unrelated, but 'tropical' note, they also included the enhanced risk for water spouts in coastal areas today.

[Trevor]

I honestly think that the COC will miss Hispaniola all together, and only scrape the northern tip of Cuba, before making landfall somewhere in the eastern Gulf.

[TWCmatthew]

NAM continues to be the far-east outlier, showing a landfall likely in northern FL or as far north as NC (however, I'm just guessing since the NAM goes out to only 84 hours) but it is certainly showing a western Atlantic storm.

The Euro continues to be the far-west outlier (even though it trended ever so slightly east with the 00z run.) It shows Isaac hitting the MS gulf coast as a hurricane.

I'll analyze further, but currently I'm forecasting a cross between a 00z GFS and 00z CMC (making landfall near the Everglades.)

[Mr. Rainman]

Isaac weakened earlier today and winds are back to 40 mph as of 2 PM this afternoon. Assuming terrain doesn't get in the way, the conditions across Isaac's forecast path are ideal for rapid intensification and the storm could still become a hurricane within the next 2 days.

It is important to note that NHC's intensity forecast is very bullish, as their forecast is well above the majority of the intensity model spread.

Satellite presentation looks better and Dvorak numbers are at 3.0 which is indicative of winds to 45 knots. Combined with recon data which has max winds of 47 knots at the vortex, I will take a guess that Isaac's estimated winds will be back up to 40 knots - 45 mph at 5 PM. As on track, I suspect a continuation of the previous track with a slight adjustment to the west yet again.

[toxictwister00]

I guess the Canadian can't be called an eastern outliner anymore, it's FINALLY jumped ship with the GFS for FL a hit, it's east of the GFS, but it's a big shift west when previously it was still aiming for N/SC hit.

There's no other word to describe the 12 ECMWF except WILD both in track and intensity. It went back west for a TX/LA landfall. That would be our Doomsday scenario if it ends up coming close to verifying, but again it's the only model going that far west and in addition it made a very radical jump back west so I'm not sure I believe that yet.

00z runs will be fun and interesting, they'll be ingested with a lot more data on the upper level pattern across the CONUS/Western Atlantic Ocean that should really help out hopefully on not only track, but give more clarity on things such as what effects on the timing of the breaking down of the C.A Ridge and timing of a trough across the CONUS will have on Isaac once heading for the Western Caribbean/Southern Gulf.

FINAL THOUGHT: I've been saying for the past few days I expect Isaac to be southwest of hitting Haiti and I still believe that now. We'll see if that's the case over the next 24-48 hours.

[TWCToday]

Someone order a hurricane?

[toxictwister00]

Track west again, includes New Orleans in the cone.

[Trevor]

11 PM ET Update (Advisory #12):
Max Winds: 45 MPH
Pressure: 1001 mb
Location: 16.7 N; 68.7 W
Movement: WNW at 18 MPH

Watches/Warnings:
All Hurricane Warnings have been discontinued with this advisory.
Tropical Storm Warning in effect for all coastlines of Hispaniola, southern tip of Cuba, and the southern Bahamas.
Hurricane Watch in effect for the coastlines of Haiti.
Tropical Storm Watch for the northern Bahamas and the middle coastlines of Cuba.


New Track...looks like the NHC finally decided to jump on board with a LA/MS/AL landfall:


I also threw this together this morning as I was getting ready for school, but never posted it. Coincidentally, AccuWeather posted a similar graphic at around 3:00 PM this afternoon.

[Mr. Rainman]

Three changes in the new track:

1) Day 1-3 forecast track has been shifted eastward.
2) Track is assuming a faster forward speed and now points to landfall on Tuesday evening.
3) Forecast landfall point has been shifted west yet again to due south of Mobile, AL - a few more shifts and it could be headed towards Louisiana.

EDIT: Geez, seems like EVERYONE was waiting on this track to come out.

[phw115wvwx]

There's way too much inconsistency in the models to pinpoint impacts for the United States with any reliability.  Everything keeps shifting westward in the latest runs, but things could easily swing back eastward in a couple days as new data arrives.  I still want to see how Isaac will cope in its journey ahead with crossing Haiti and Cuba.

[toxictwister00]

This 1851 hurricane looks like a decent analog right about now. (Up to landfall that is)