ATL: ISAAC - Post-Tropical - Discussion

[jlauderdal]

winds gusting well over 50mph and transformers lighting up the sky to my east

That's weird in my neighborhood the trees are still.

you must be in the eye of the storm if your trees are still

[Hurricane Alexis]

winds gusting well over 50mph and transformers lighting up the sky to my east

That's weird in my neighborhood the trees are still.

you must be in the eye of the storm if your trees are still

Miami international is reporting winds of 9 mph right now.

[senorpepr]

Looks like Hurricane watches issued now for northern gulf coast, including NOLA region per the 5 am advisory

NOT including NOLA.

A HURRICANE WATCH HAS BEEN ISSUED FROM THE MOUTH OF THE MISSISSIPPI
RIVER EASTWARD TO INDIAN PASS FLORIDA...NOT INCLUDING METROPOLITAN
NEW ORLEANS.

[Dydion]

I think it's dumb to make that exception.

Just my opinion.

[jinftl]

NATIONAL WEATHER SERVICE MIAMI FL
525 AM EDT SUN AUG 26 2012

FLZ067-068-071-072-168-172-261000-
COASTAL BROWARD COUNTY FL COASTAL PALM BEACH COUNTY FL INLAND BROWARD
COUNTY FL INLAND PALM BEACH COUNTY FL METRO BROWARD COUNTY FL METRO
PALM BEACH COUNTY FL
525 AM EDT SUN AUG 26 2012

...A SIGNIFICANT WEATHER ADVISORY IS IN EFFECT FOR NORTHEASTERN
BROWARD COUNTY...SOUTHEASTERN PALM BEACH COUNTY...FOR THE DEVELOPMENT
OF FUNNEL CLOUDS...

* UNTIL 600 AM EDT

* AT 523 AM EDT...NATIONAL WEATHER SERVICE METEOROLOGISTS DETECTED
HEAVY SHOWERS 3 MILES SOUTH OF DELRAY BEACH...AND MOVING WEST AT
40 MPH.

* THE STORM WILL AFFECT...
FAU SOUTH CAMPUS...
WHISPER WALK...
SOUTH COUNTY REGIONAL PARK...
PARKLAND...
AND SURROUNDING COMMUNITIES.

[Bluefrog]

Wow on the NOLA call. That may be a big regret later today tomorrow.

[WeatherGuesser]

How much of a surge can Mobile Bay handle? If this track holds, Mobile could be in for a direct hit.

[Bluefrog]

How much of a surge can Mobile Bay handle? If this track holds, Mobile could be in for a direct hit.

Yeah I'm interested in storm surge potential too for here.

[rtd2]

Wow on the NOLA call. That may be a big regret later today tomorrow.

A few more west trending model runs may put NOLA under a watch later today or tonight.... but I see no reason for NHC to pull the Trigger on NOLA at this advisory. besides I think they have one of those BREAK GLASS emergency pull box for NOLA (LOL Joke)

[Weeks Bay]

Katrina was 11ft at the upper end of the bay,with 8ft at mouth of weeks bay.

[GCANE]

AMSU analysis shows a very wide warm core

http://amsu.ssec.wisc.edu/archive/2012/ ... _xsect.gif

However, a boundary-layer inversion is currently in place which is inhibiting convection.

http://rammb.cira.colostate.edu/product ... 1208260220

I suspect CIN will shake out this afternoon with solar heating over FL and Cuba which will heat the boundary layer and remove the inversion.

CAPE is currently 4000 to the NW of Isaac in the GOM.

http://www.spc.noaa.gov/exper/mesoanaly ... sector=18#

Excellent outflow channel in place due to ULL at 20N 60W

http://tropic.ssec.wisc.edu/real-time/w ... zoom=&time

Looks like the anti-cyclone is behind Isaac's track and there is also a 300mb PV anomaly associated with it.

http://tropic.ssec.wisc.edu/real-time/w ... oom=&time=

This may limit Isaac's vorticity column from stretching too much vertically today.

So, we may see convection fire up later today, but may not see too much strengthening.

Of cousre, if a hot-tower pops up, that could all change.

[CYCLONE MIKE]

Reason N.O. is not in watch yet is because they are not ready to start evacs yet. As soon as watch is issued it puts things in motion. Plus the forecast is so uncertain right now as well. We have seen how fast models can swing .

[jinftl]

Very impressive analysis by NWS New Orelans/Baton Rouge - i think folks need to understand that no one at the NHC or NWS offices etc is going to drop the ball here and screw over New Orleans. They are clearly on top of the situation and state it may change. These are the same folks and agencies that 7 years ago were pleading with New Orleans officials to order a mandatory evacuation long before the Mayor ever did. They won't fail the city this time either.

This is an analysis of the models and forecast trends that puts alot of others to shame!


AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NEW ORLEANS LA
506 AM CDT SUN AUG 26 2012

...HURRICANE WATCH ISSUED FOR THE MISSISSIPPI GULF COAST AND FOR
LOWER ST. BERNARD AND LOWER PLAQUEMINES PARISHES IN LOUISIANA...
.

.LONG TERM...

NO ON TO THE TOPIC OF MAIN CONCERN...TROPICAL STORM ISAAC. ISAAC
IS LOCATED ABOUT 200 MILES TO THE EAST-SOUTHEAST OF KEY WEST AND
MOVING TOWARDS THE NORTHWEST AT 18 MPH. THE OVERALL STRUCTURE OF
THE STORM CONTINUES TO LOOK RAGGED ON SATELLITE WITH LIMITED DEEP
CONVECTION MAINLY OFF TO THE NORTH AND EAST OF THE CENTER. THAT
SAID...A RECONNAISSANCE FLIGHT HAS FOUND A SLIGHTLY LOWER PRESSURE
OF 995 MB AND WINDS OF 65 MPH. THE NEW FORECAST TRACK FROM THE
NATIONAL HURRICANE CENTER CONTINUES TO SHOW ISSAC MOVING GENERALLY
IN A WEST-NORTHWEST TO NORTHWEST MOTION TOWARDS THE FLORIDA KEYS
AND THE GULF OF MEXICO. IN THE SHORT TERM...THE NEXT 36
HOURS...THE MODEL GUIDANCE IS IN GOOD AGREEMENT ON THAT TRACK.

BY EARLY MONDAY MORNING THE HURRICANE CENTER TRACK PUTS ISSAC
AROUND 100 MILES TO THE NORTHWEST OF KEY WEST AND INTO THE GULF OF
MEXICO. ONCE ISAAC REACHES THE GULF...STRENGTHENING IS FORECAST.
AT THAT POINT...MOST OF THE RELIABLE MODEL GUIDANCE IS STILL IN
DECENT AGREEMENT WITH THE ECMWF...THE GFS...THE NAM AND THE CMC
ALL IN REASONABLE AGREEMENT WITH THE CANADIAN THE FURTHEST WEST.
THAT IS WHERE THINGS START TO GET A LITTLE...OFF. THE DIFFERENCES
IN THE MODEL RUNS HINGE MOSTLY ON HOW THEY HANDLE THE EVOLUTION OF
A SHORTWAVE TROUGH AND HIGH PRESSURE RIDGES TO THE WEST AND THE
EAST OF SAID TROUGH. THE GFS AND THE CMC SHOW THE TROUGH
BYPASSING ISSAC AND THE TWO RIDGES CLOSING THE GAP BETWEEN THEM
LEAVING ISSAC BEHIND TO CONTINUE IN A NORTHWESTWARD MOTION TOWARD
THE CENTRAL GULF COAST. THE NAM AND THE ECMWF BOTH LEAVE ENOUGH OF
A WEAKNESS OVER THE EASTERN FLORIDA PANHANDLE TO ALLOW FOR A
NORTHERLY MOTION TOWARDS THE END OF THE TRACK. DISCOUNTING THE NAM
FOR ITS NOTORIOUS ISSUES IN THE TROPICS...AND WITH THE IDEA THAT
THE ECMWF WAS ONE OF...IF NOT THE BEST...PERFORMING MODELS IN THE
RECENT PAST SOME COMPARISONS WERE DONE ON THE LAST TWO RUNS. THE
12Z RUN YESTERDAY TOOK ISSAC INTO THE FLORIDA PANHANDLE NEAR
APALACHICOLA. THE 00Z RUN FROM A FEW HOURS AGO SHOWS A LANDFALL
POINT NEAR THE FLORIDA/ALABAMA BORDER. THE 00Z RUN OF THE MODEL
DEFINITELY SHOWED A STRONGER ATLANTIC RIDGE WHICH ACCOUNTED FOR
THE PUSH FURTHER WEST AS THERE WAS LITTLE DIFFERENCE IN THE
EVOLUTION OF THE TROUGH IN THE TWO RUNS. THIS WILL BE WATCHED
CLOSELY IN THE NEXT RUN SINCE IT REMAINS ONE OF THE EASTERN MOST
MODELS AT THIS POINT. SHOULD IT SHIFT MORE TO THE WEST AND THE
OTHER MODELS CONTINUE THEIR WESTWARD SHOWING...ADDITIONAL
ADJUSTMENTS TO THE HURRICANE CENTER ARE POSSIBLE.

FOR THE TIME BEING HAVE GONE WITH A BLEND OF THE ECMWF AND THE GFS
WITH A BIT MORE WEIGHT PLACED ON THE ECMWF SINCE IT IS CLOSER TO
THE CURRENT HURRICANE CENTER FORECAST TRACK. THIS WILL BRING THE
POSSIBILITY OF TROPICAL STORM CONDITIONS INTO THE AREA ON MONDAY
NIGHT ALONG THE EASTERN PARTS OF THE MISSISSIPPI GULF COAST AND
TUESDAY MORNING INTO THE NEW ORLEANS METRO AREA. HURRICANE
CONDITIONS WILL ALSO BE POSSIBLE...ESPECIALLY BY TUESDAY MORNING
ALONG THE MISSISSIPPI COAST. RAIN CHANCES WILL OBVIOUSLY BE
DEPENDENT ON THE EVENTUAL TRACK OF ISAAC...AND THEY CURRENTLY
REFLECT SOME OF THE UNCERTAINTY IN THE FORECAST TRACK AS
MENTIONED IN THE NATIONAL HURRICANE CENTER DISCUSSION.

NEEDLESS TO SAY...THIS IS A DEVELOPING AND FLUID SITUATION THAT
CAN CHANGE GREATLY OVER THE NEXT 24-36 HOURS. THE BOTTOM LINE IS
THAT PARTS OF THE AREA ARE NOW UNDER A HURRICANE WATCH AND IN
THOSE AREA PREPARATIONS SHOULD BE RUSHED TO COMPLETION AS QUICKLY
AS POSSIBLE. OUTSIDE THE HURRICANE WATCH...RESIDENTS SHOULD
CONTINUE TO MONITOR THE LATEST UPDATES ON ISAAC AND BE PREPARED TO
TAKE ACTION IF NEEDED.

[jlauderdal]

5500 without power in dade/broward and not too much action so far




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[sammy126]

forecast for venice, fl sunday night and monday winds 25 to 40 mph and heavy rain.

[CYCLONE MIKE]

Nice find jinftl. Only thing that kinda surprises me is lack of confidence in gfs. The btr/msy office usually puts more weight in the gfs model for all their forecast. Guess it's a wait and see for them as well before going all in

[Cyclenall]

URNT12 KNHC 260813
VORTEX DATA MESSAGE AL092012
A. 26/07:33:40Z
B. 22 deg 54 min N
078 deg 39 min W
C. 850 mb 1391 m
D. 43 kt
E. 061 deg 73 nm
F. 128 deg 69 kt
G. 065 deg 81 nm
H. 995 mb
I. 19 C / 1520 m
J. 20 C / 1520 m
K. NA / NA
L. NA
M. NA
N. 12345 / 8
O. 0.02 / 0.5 nm
P. AF301 1809A ISAAC OB 11
MAX FL WIND 69 KT NE QUAD 07:07:30Z
;

This is a very strange TS at the moment, it looks terrible but is close to hurricane strength! To be honest, I expected more by now but another huge win by the NHC...they forecasted the last 12 hours perfectly again unlike me. The LLC is still intact but I heard that it may not be stacked as well as it should be . I also hate the speed, way too fast. There has been constant convection over Cuba for a long time now...bursting of deep convection and I can't tell if its from Isaac or something else. With that said, this can easily pop at anytime despite its current appearance just like what it did before Haiti...its amazing how fast that convection can wrap.

So, we may see convection fire up later today, but may not see too much strengthening.

Of cousre, if a hot-tower pops up, that could all change.

Whats next!! In relation to the 2nd point, it could snap Isa's core back .

[karenfromheaven]

How much of a surge can Mobile Bay handle? If this track holds, Mobile could be in for a direct hit.

Yeah I'm interested in storm surge potential too for here.

Have you checked out the Storm Surge Exceedance link on the NHC Isaac page? It has a nice zoomable Google map showing areas that may become submerged, right down to the street level! http://www.nhc.noaa.gov/refresh/graphics_at4+shtml/092352.shtml?gm_esurge#contents

[jinftl]

Snagged this off wunderground observation in my area right now....power just flickered as winds gusted

5500 without power in dade/broward and not too much action so far




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[jlauderdal]

Snagged this off wunderground observation in my area right now....power just flickered as winds gusted

5500 without power in dade/broward and not too much action so far




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that's 2 miles from my place, that lone cell went through and woke up the rest of the crew at my place, last 2 mins but these cells are moving over 30 so they dont last long