Wx Infinity Forums

Look like a little wobble to the NW. It might be far away from the coast now to let the core fully wrap and allow intensification.

11AM is out. Another shift west to Biloxi, MS and warnings extended westward in LA. They're not pulling the trigger yet on NOLA but it's now awfully close. Even this track would be bad news....

TROPICAL STORM ISAAC DISCUSSION NUMBER 22
NWS NATIONAL HURRICANE CENTER MIAMI FL AL092012
1100 AM EDT SUN AUG 26 2012

VISIBLE SATELLITE AND IMAGERY SUGGEST THAT THE TROPICAL CYCLONE IS
GRADUALLY BECOMING BETTER ORGANIZED. THERE ARE INDICATIONS OF
INNER CORE DEVELOPMENT WITH INCREASED CONVECTION NEAR AND OVER THE
CENTER...AND A PARTIAL EYEWALL IS IN EVIDENCE ON RADAR IMAGERY. THE
BANDING FEATURES HAVE BECOME MORE DISTINCT OVER THE NORTHERN AND
EASTERN SEMICIRCLES OF THE CIRCULATION. THE CURRENT INTENSITY
ESTIMATE IS HELD AT 55 KT PENDING OBSERVATIONS FROM AN AIR FORCE
HURRICANE HUNTER AIRCRAFT THAT SHOULD BE IN THE CENTER SHORTLY.
ISAAC CONTINUES TO EXHIBIT A WELL-DEFINED UPPER-LEVEL OUTFLOW
PATTERN...AND GRADUAL STRENGTHENING IS LIKELY AS THE CYCLONE
TRAVERSES THE EASTERN GULF OF MEXICO OVER THE NEXT COUPLE OF DAYS.
THE OFFICIAL WIND SPEED FORECAST IS SIMILAR TO THE PREVIOUS NHC
FORECAST AND IS ALSO CLOSE TO THE LATEST STATISTICAL-DYNAMICAL
GUIDANCE.

THE TRACK FORECAST BEYOND DAY 2 HAS BECOME PROBLEMATIC. DYNAMICAL
MODELS DEPICT THE CYCLONE MOVING INTO A BREAK IN THE SUBTROPICAL
RIDGE NORTH OF THE GULF COAST IN ABOUT 72 HOURS. HOWEVER THERE IS
A LARGE SPREAD AMONG THE MORE RELIABLE TRACK MODELS. FOR EXAMPLE...
THE ECMWF FORECAST IS ABOUT 300 N MI EAST OF THE GFS SOLUTION AT DAY
3. SINCE THE DYNAMICAL MODEL CONSENSUS HAS SHIFTED WESTWARD...THE
OFFICIAL TRACK FORECAST IS MOVED A BIT TO THE WEST OF THE PREVIOUS
ONE. THIS REQUIRES AN EXTENSION OF THE HURRICANE WATCH WESTWARD
ALONG THE LOUISIANA COAST. IT SHOULD BE NOTED THAT THERE IS
GREATER THAN USUAL UNCERTAINTY IN THE TRACK FORECAST.

THROUGHOUT THE PERIOD...IT IS IMPORTANT NOT TO FOCUS ON THE EXACT
FORECAST TRACK SINCE SIGNIFICANT HAZARDS EXTEND WELL AWAY FROM THE
CENTER.


FORECAST POSITIONS AND MAX WINDS

INIT 26/1500Z 23.9N 80.8W 55 KT 65 MPH
12H 27/0000Z 25.0N 82.7W 65 KT 75 MPH
24H 27/1200Z 26.1N 84.8W 70 KT 80 MPH
36H 28/0000Z 27.4N 86.4W 75 KT 85 MPH
48H 28/1200Z 28.5N 87.6W 80 KT 90 MPH
72H 29/1200Z 30.5N 89.0W 90 KT 105 MPH
96H 30/1200Z 32.5N 89.5W 30 KT 35 MPH...INLAND
120H 31/1200Z 34.5N 89.5W 20 KT 25 MPH...INLAND

$$
FORECASTER PASCH/ROBERTS

Another shift west at the 5 p.m. (eastern time) forecast issuance and parts of Texas will be in the multi-day cone, it seems.

Track is over Keesler AFB on Wednesday morning.

Highlight from the disco. This honestly has become one of the more challenging forecasts I can remember in terms of how different the landfall points could eventually be within such a small time frame.

THE TRACK FORECAST BEYOND DAY 2 HAS BECOME PROBLEMATIC. DYNAMICAL
MODELS DEPICT THE CYCLONE MOVING INTO A BREAK IN THE SUBTROPICAL
RIDGE NORTH OF THE GULF COAST IN ABOUT 72 HOURS. HOWEVER THERE IS
A LARGE SPREAD AMONG THE MORE RELIABLE TRACK MODELS. FOR EXAMPLE...
THE ECMWF FORECAST IS ABOUT 300 N MI EAST OF THE GFS SOLUTION AT DAY
3. SINCE THE DYNAMICAL MODEL CONSENSUS HAS SHIFTED WESTWARD...THE
OFFICIAL TRACK FORECAST IS MOVED A BIT TO THE WEST OF THE PREVIOUS
ONE. THIS REQUIRES AN EXTENSION OF THE HURRICANE WATCH WESTWARD
ALONG THE LOUISIANA COAST. IT SHOULD BE NOTED THAT THERE IS
GREATER THAN USUAL UNCERTAINTY IN THE TRACK FORECAST.

Portastorm wrote:Another shift west at the 5 p.m. (eastern time) forecast issuance and parts of Texas will be in the multi-day cone, it seems.

Portstorm if that happens is it time to start injecting Texas into the conversation concerning landfall.

cperk wrote:

Portastorm wrote:Another shift west at the 5 p.m. (eastern time) forecast issuance and parts of Texas will be in the multi-day cone, it seems.

Portstorm if that happens is it time to start injecting Texas into the conversation concerning landfall.

Maybe ... but what caught my eye was the 24-hour postion on Thursday and how the current cone almost touches northeast Texas. I was just thinking if the landfall spot keeps moving west ... part of our state is bound to be in the cone if this keeps up. I personally still think a Texas landfall is a big stretch here, but if the storm slows to a crawl near landfall and drifts west like some of the modeling is suggesting ... it could get quite interesting.

What I also find interesting is how many of us thought the various G-IV data and extra sampling would help narrow down the forecast but it doesn't appear to have done so. That's not to say it hasn't helped but it just goes to show, like Scott pointed out, that this is one very complicated scenario. The good men and women at NHC have their hands full.

This makes it tough to determine a destination spot for any storm chasers out there, but currently New Orleans looks prime now (unfortunately) with MS, AL, to Fl panhandlle still open.

Key West Radar suggests that the center of Isaac will pass just S of Sand Key Light C-MAN Station which is about 7 miles SSW of Key West on the Reef...

Portastorm wrote:

cperk wrote:

Portastorm wrote:Another shift west at the 5 p.m. (eastern time) forecast issuance and parts of Texas will be in the multi-day cone, it seems.

Portstorm if that happens is it time to start injecting Texas into the conversation concerning landfall?

Maybe ... but what caught my eye was the 24-hour postion on Thursday and how the current cone almost touches northeast Texas. I was just thinking if the landfall spot keeps moving west ... part of our state is bound to be in the cone if this keeps up. I personally still think a Texas landfall is a big stretch here, but if the storm slows to a crawl near landfall and drifts west like some of the modeling is suggesting ... it could get quite interesting.
What I also find interesting is how many of us thought the various G-IV data and extra sampling would help narrow down the forecast but it doesn't appear to have done so. That's not to say it hasn't helped but it just goes to show, like Scott pointed out, that this is one very complicated scenario. The good men and women at NHC have their hands full.

This - this is the best post all day. Guy and gals - if you don't read anything else all day, just take this post and chew on it for a few hours. I'm going to take care of yard work and do this very thing.

0z GFS through 24 hrs is just a bit to the E of 6z. Only by a small amount. Not far enough into the run to tell if it will be picked up to the N or show something similar to the previous tracks.

AF RECON pass suggest 23.667N 80.950W 996.1mb extrap

Hr 48 W of 6z run

S of Mississippi mouth

Hour 54:

Hr 60

Just offshore Houma

Again I advise anyone that this is just one model run and to please not take it verbatim.

Hr 66

Moving W along the coast

Hr 78

S of Morgan City/Abbeville

Just offshore

Isaac really looks like he is shaping up nicely again.

http://www.ssd.noaa.gov/goes/east/carb/flash-wv.html

The song remains the same. At this time, everybody from SE Texas to just east of LA should really monitor the NHC write ups, as well as your local news. Folks in NOLA know the drill.

I am wondering if wxman57 still feels that Texas is protected from Isaac by high pressure?
What say he? What is his personal opinion about it going into LA and moving off to the north and northeast from there?
Has he had to rethink as of this morning?

A good resource to use now is Dr. Ryan Maue's Twitter feed. Some of you know his WeatherBell models site (still free). He is putting up animation model runs almost as soon as they come out.