ATL: ISAAC - Post-Tropical - Discussion

[jlauderdal]

Hurricane warnings for Keys and SW FL and Watch now for Miami-Dade county!

TROPICAL STORM ISAAC FORECAST/ADVISORY NUMBER 17
NWS NATIONAL HURRICANE CENTER MIAMI FL AL092012
0900 UTC SAT AUG 25 2012

CHANGES IN WATCHES AND WARNINGS WITH THIS ADVISORY...

A HURRICANE WARNING HAS BEEN ISSUED FOR THE FLORIDA KEYS INCLUDING
THE DRY TORTUGAS...THE WEST COAST OF FLORIDA FROM BONITA BEACH
SOUTHWARD...AND FLORIDA BAY.

A HURRICANE WATCH HAS BEEN ISSUED FOR THE FLORIDA EAST COAST FROM
GOLDEN BEACH SOUTHWARD.

THE GOVERNMENT OF THE BAHAMAS HAS ISSUED A HURRICANE WATCH FOR
ANDROS ISLAND.

Smart move-

with all this fuss and muss over isaac for over a week, I could see a ridonkulous amount of people piling up traffic in the miami area.. it is about time they warn these people

there is very specific criteria to issue watches/warnings and the criteria is being met at this time...as far as traffic goes, dont expect to see some mass evacuation or anything like that because that isnt required nor will it be recommended

[meriland23]

Right now Iaac contines to be on the eastern envelope of the models with a nw/nnw trajectory....He will be back over water later today and it looks less likely there will not be much of an issue with land thereafter....could easily be a 2 when hearing keys/sfl sunday night

'if' it gets to the keys.. if this new path is true, I would be more concerned for west palm beach and those areas

[jinftl]

From 5am NHC Discussion:

GIVEN THAT THE CYCLONE HAS FARED RATHER WELL AFTER MOVING ACROSS
HAITI...AND THAT THE TRACK FORECAST HAS ONLY MINIMAL INTERACTION
WITH CUBA...THE INTENSITY FORECAST AFTER 12 HOURS HAS BEEN ADJUSTED
UPWARD FOLLOWING THE TREND OF THE LATEST INTENSITY GUIDANCE. ISAAC
IS EXPECTED TO BECOME A HURRICANE IN ABOUT 36 HOURS...WITH
ADDITIONAL INTENSIFICATION EXPECTED AS THE CYCLONE MOVES INTO THE
EASTERN GULF OF MEXICO IN A FAVORABLE ENVIRONMENT. THE NEW NHC
INTENSITY FORECAST IS CLOSE TO THE INTENSITY CONSENSUS AIDS THROUGH
72 HOURS AND FOLLOWS A BLEND OF THE DECAY SHIPS AND LGEM AFTERWARD.

IT IS IMPORTANT NOT TO FOCUS ON THE EXACT TRACK OF ISAAC DUE TO THE
UNCERTAINTIES IN THE FORECAST AND THE FACT THAT ISAAC HAS A LARGE
AREA OF TROPICAL STORM FORCE WINDS ASSOCIATED WITH IT.

[jhpigott]

If Issac stays on the eastern side of the model guidance I would not be shocked if the hurricane watches/warnings were extended up the FL east coast

[Canelaw99]

Here's a handy little graphic of the breakpoints used for the state of FL. I know some people don't know where the watch/warning locations are located. http://www.nhc.noaa.gov/breakpoints/images/bp_se_11.jpg

[jinftl]

Probability of at least sustained tropical storm force winds is increasing statewide...now over 50% chance from a line south and west of West Palm to Tampa to Apalachicola. By the time is all said and done, Isaac could bring ts winds to almost the entire state!!!

[Canelaw99]

Now the question for us S Dade folks is-- to what extent do we prep? Fill gas cans for generator? Probably, just because we can lose power with a t-storm. Do we shutter the house? Thoughts? I realize it's only predicted to be a cat 1, barely, but isn't the rule of thumb prepare for one cat higher, just because intensity is so hard to predict? Ah, the joys of the tropics lol

[tgenius]

From what it appears I'm going to have a busy weekend for work :/ at what point would that hurricane watch become a warning for dade, 11am?

[jinftl]

I would say wait on the shutters until later advisories at 11am and see if the watch is upgraded to a warning. I would definitely prepare for power outages and all that comes with that...i am planning for the same up here in Broward. Sustained winds of 50+ mph with gusts to 70mph can easily knock out power...and that means a/c....ugh

Just remember Katrina was 'just a cat 1' when she blew through south florida...

A track through the middle or lower Keys would likely bring tropical storm conditions to Miami north. A track into the right of the forecast cone would bring potentially a hurricane into Miami-Dade and would like require hurricane warnings up through Broward. NHC seems to be leaning towards Keys track right now based on warnings issued for Keys and Naples/Fort Myers.

Now the question for us S Dade folks is-- to what extent do we prep? Fill gas cans for generator? Probably, just because we can lose power with a t-storm. Do we shutter the house? Thoughts? I realize it's only predicted to be a cat 1, barely, but isn't the rule of thumb prepare for one cat higher, just because intensity is so hard to predict? Ah, the joys of the tropics lol

[Canelaw99]

Very good reminder about K being a 1.

[Myersgirl]

If I read it correctly, we are not under a watch or a warning here in Fort Myers.

[jinftl]

You are correct...my bad...Bonita Springs is south of Ft Myers...by 11am that could be a different story...and i hate to say it, Tampa is going to see significant impacts too.

If I read it correctly, we are not under a watch or a warning here in Fort Myers.

[Cyclenall]

THE CIRCULATION OF ISAAC HAS REMAINED RELATIVELY INTACT AFTER MOVING
ACROSS THE SOUTHWESTERN PENINSULA OF HAITI OVERNIGHT. BEFORE THE
CENTER MOVED INLAND...HURRICANE HUNTER AIRCRAFT DATA SUGGESTED THAT
THE CYCLONE HAD PEAK WINDS OF ABOUT 55 KT. ASSUMING THE CYCLONE
WEAKENED A LITTLE AFTER ENCOUNTERING THE HIGH TERRAIN...THE INITIAL
INTENSITY IS LOWERED TO 50 KT FOR THIS ADVISORY.

I thought this got up to 60 knots before landfall? I don't agree with it being 55 knots at peak and not 50 knots now. I think its 5 knots higher for both values as recon can't quite get in there yet. I also see they used the word "assume" in there but the presentation hasn't degraded enough to lower it 10 knots in 7-8 hours IMO.

landfall miami


http://raleighwx.americanwx.com/models/ ... ort036.gif

I don't believe that speed.

I'm reading thoughts that if Issac is way far north and east of forecast positions in the short term...making land much less of an issue...that it means the medium and long range track will automatically shift east. Something tells me its not going to be that simple . It depends on when the movement shifts back again and any erratic motions.

EDIT: Uhhh how did this post end up in the models thread? I was on the general discussion thread and when it went through, it ended up here!! That's never happened before, can a staff member move it back, thanks.

[drudd1]

It will be an interesting weekend for sure. We are actually located roughly between Orlando and Titusville on the East Coast and there is nothing between us and the coast but the St. John's River and it's surrounding swamps and the coast, so what they get we usually get. Since our power goes out in thunderstorms on a regular basis, sigh, generator is ready. We will get pretty much the same wind they have coming off the Atlantic in Brevard county. Having been stationed at Homestead many years ago Canelaw99, I can only say what I would do and that is fill the cans and see what the neighbors are doing with all their light lawn furniture and garbage cans. I personally would not have boarded back then, but since have been up close and personal with the tornadoes that just love to imbed within these systems' bands; I can't honestly tell you what I would do down there now. Fortunately, this is not an Andrew, far from it, so doing what makes you feel best is what's important.

[jinftl]

From 5am advisory, probability of sustained winds of 34kts (39 mph), 50kts (58 mph), and 64 kts (74 mph) are as follows - interesting to watch the trend of these at 11am, 5pm, etc updates today:

MIAMI FL 34kts - 67%
MIAMI FL 50kts - 19%
MIAMI FL 64kts - 4%

MARATHON FL 34kts - 80%
MARATHON FL 50kts - 47%
MARATHON FL 64kts - 16%


KEY WEST FL 34kts - 72%
KEY WEST FL 50kts - 39%
KEY WEST FL 64kts - 16%


FT MYERS FL 34kts - 68%
FT MYERS FL 50 kts - 27%
FT MYERS FL 64kts - 9%


TAMPA FL 34kts - 57%
TAMPA FL 50kts - 17%
TAMPA FL 64kts - 5%

http://www.nhc.noaa.gov/text/refresh/MI ... 0846.shtml

[Myersgirl]

Is it odd that watches are further North on the East coast than the West?

[northjaxpro]

Not to take the focus away from Isaac, but FWIW, there appears to be a small spin, probably mid-level, riding just north of the coast of Cuba. Key West radar is showing that quite well. This little disturbance has caused heavy rains already across the extreme SE FL and through the Keys and to the coast of Cuba.

http://radar.weather.gov/ridge/radar.ph ... X&loop=yes

[jinftl]

Part of that is just timing...the impacts could first be felt on the east coast but then 12 or so hours later, the west coast could bear the brunt...those watches/warnings are 6-12 hours away if the current forecast holds

Is it odd that watches are further North on the East coast than the West?

[SouthFLTropics]

Not to take the focus away from Isaac, but FWIW, there appears to be a small spin, probably mid-level, riding just north of the coast of Cuba. Key West radar is showing that quite well. This little disturbance has caused heavy rains already across the extreme SE FL and through the Keys and to the coast of Cuba.

http://radar.weather.gov/ridge/radar.ph ... X&loop=yes

I have noticed that as well and I can't help but wonder if this feature that has developed is creating the more poleward motion in Isaac that we are seeing. Not sure if the models picked up on this or not. It's almost like Isaac and this feature are having a fujiwara effect on each other.

SFT

[northjaxpro]

Not to take the focus away from Isaac, but FWIW, there appears to be a small spin, probably mid-level, riding just north of the coast of Cuba. Key West radar is showing that quite well. This little disturbance has caused heavy rains already across the extreme SE FL and through the Keys and to the coast of Cuba. http://radar.weather.gov/ridge/radar.ph ... X&loop=yes

I have noticed that as well and I can't help but wonder if this feature that has developed is creating the more poleward motion in Isaac that we are seeing. Not sure if the models picked up on this or not. It's almost like Isaac and this feature are having a fujiwara effect on each other. SFT

I have been following this little disturbance since last night when it came across Miami and through the Keys. It has a fairly decent concentration of convection. Again. observing Key West radar, there is definitely some rotation within that convection just off the northern coast of Cuba. I too definitely think it is playing a role with interacting with Isaac.