Isaac remains disorganized

By: Dr. Jeff Masters , 8:29 PM GMT on August 23, 2012

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Tropical Storm Isaac has strengthened slightly, data from the hurricane hunters show, but the storm remains disorganized and difficult to forecast. If you have to make decisions based upon what Isaac will do, I highly recommend that you wait until at least Friday morning to make a decision, if at all possible, as the forecasts then should be of significantly higher accuracy. Isaac continues to have a large area of light winds about 50 miles across near its center. This makes the storm subject to reformations of the center closer to areas of heavy thunderstorms that form, resulting in semi-random course changes. Until Isaac consolidates, the lack of a well-defined center will make forecasts of the storm's behavior less accurate than usual. An Air Force Reserve hurricane hunter aircraft is in Isaac this afternoon, and has found that surface tropical storm-force winds on the east side of the storm, south of Puerto Rico, have undergone a modest expansion. These winds were mostly in the 40 mph range, with a few areas of 45 mph winds. The surface pressure remained fairly high, at 1004 mb. Infrared and visible satellite loops show that Isaac has fairly symmetric circular cloud pattern, with developing spiral bands that are contracting towards the center, which suggests intensification. However, the storm has a very clumpy appearance, and is a long way from being a hurricane. Given the storm's continued reluctance to organize, Isaac is unlikely to reach hurricane strength before encountering Haiti and Cuba. An analysis of upper level winds from the University of Wisconsin CIMSS shows an upper-level outflow channel well-established to the north, and an intermittent outflow channel to the south. Radar imagery from Puerto Rico shows some weak low-level spiral bands that haven't changed much in intensity or organization this afternoon. NOAA buoy 42060 reported 1-minute mean winds of 35 mph and a wind gust of 40 early this afternoon. At St. Thomas in the Virgin Islands, wind gusts up to 45 mph were observed early this afternoon. Isaac's rains caused major flooding last night in Trinidad and Tobago, the southernmost islands of the Lesser Antilles chain, according to the Trinidad Express. Isaac's rains have not been heavy enough today to cause flooding problems on other islands.


Figure 1. True-color MODIS image of Isaac taken at 1:40 pm EDT August 23, 2012. Image credit: NASA.

Latest model runs for Isaac
The latest set of 12Z (8 am EDT) model runs have shifted to the west compared to the previous set of runs. The models continue to show a west-northwestward track to a point on the south coast of Hispaniola, then across eastern Cuba and into the Florida Straits between Florida and Cuba. A trough of low pressure is then expected to pull Isaac to the northwest and then north, towards the Florida Panhandle. The big news in this model cycle is that both of our top models--the GFS and ECMWF--predict that 5 - 6 days from now, the trough of low pressure pulling Isaac to the north may not be strong enough to finish the job. These models predict that the trough will lift out and a ridge of high pressure will build in, forcing Isaac more to the west. The GFS predicts this will occur after Isaac makes landfall in the Florida Panhandle, resulting in Isaac moving slowly to the west over land, from Georgia to Alabama. The ECMWF predicts the westward motion will happen while Isaac is in the northern Gulf of Mexico, resulting in an eventual landfall near the Louisiana/Texas border on Thursday. There are some huge issues to resolve to make an accurate long-range track forecast for Isaac. Where will its center consolidate? How will the interaction with the mountains of Hispaniola and Cuba will affect it? Where will Isaac pop off the coast of Cuba? Hopefully, the data being collected by the NOAA jet this afternoon will give us a more unified set of model forecasts early Friday morning. For now, pay attention to the cone of uncertainty. If you're in the cone, you might get hit.



Figure 2. Predicted 5-day rainfall total ending at 8 am EDT Tuesday August 28 from Tropical Storm Isaac. Graphics were generated from the 12Z (8 am EDT) August 23, 2012 run of the HWRF model (top) and GFDL model (bottom). The heaviest rainfall is expected to occur in a 50 - 80 wide wide swath along and to the right of where the center tracks. Amounts in excess of 8 inches (yellow colors) are predicted for portions of the Dominican Republic and Haiti from the HWRF model, but not the GFDL model. Given the current disorganization of Isaac, these rainfall amounts are probably at least 20% too high. Image credit: Morris Bender, NOAA/Geophysical Fluid Dynamics Laboratory.

Jeff Masters

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Quoting HurricaneDean07:

Nope. MLC near 14.5N LLC near 16 N



LLC is either going to get ejected or pulled back south if the deepening on the W side keeps up. Not that I've ever been convinced of the N position the HH gave it anyway.


The W. Side of the storm is feeling some good conditions past 70W and is expanding in that direction like crazy.



That has a 50 minute delay. Now look at unenhanced IR and see how fast that expanded in the past 1 or 2 frames.

The S.A. continental dry line may be sealed off in a few hours at this rate, which has been one of the bigger factors screwing up intensification before now...
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1823. auburn (Mod)
Quoting AllyBama:
WOW! Even TK and Aubie are here tonight.


Good to see you too..
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LOCATION...16.7N 68.7W Is this an arbitrary number?


goodnight
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Quoting angiest:

But adjusted further left later on.


that's not what they said in the discussion
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Darn! The "H" is sitting right at the entrance to Mobile Bay..grrr
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1819. yoboi
Quoting moonlightcowboy:


Yes. This bugs me.


that trough that ya are saying bugs ya is the deciding factor where isaac will go if ya can figure it out ya will nail isaac forcast...good luck
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Wow, still racing at 18 mph. Another reason this storm is having trouble "stacking itself".
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Quoting HurricaneDean07:
CONE SHIFTED WESTWARD EVEN MORE.


not the whole thing.


THE OFFICIAL FORECAST IS NUDGED A BIT TO THE RIGHT OF
THE PREVIOUS ONE AND IS SOMEWHAT FASTER BASED ON THE LATEST MODEL
GUIDANCE.
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I still believe the NHC intensity forecast is entirely too low. Conditions are going to be very favorable for rapid intensification in the Gulf.
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1814. angiest
Quoting WPBHurricane05:
As expected:

THE MODEL CONSENSUS HAS SHIFTED A BIT TO THE RIGHT DURING THE FIRST HALF OF THE FORECAST PERIOD...PRIMARILY DUE TO AN EASTWARD SHIFT OF THE LATEST GFS TRACK. THE OFFICIAL FORECAST IS NUDGED A BIT TO THE RIGHT OF THE PREVIOUS ONE AND IS SOMEWHAT FASTER BASED ON THE LATEST MODEL GUIDANCE.

But adjusted further left later on.
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1813. centex
If you don't get to wrapped up in the ill defined LLC and look at the system over last couple days and track, west is the obvious choice. Funny how this is so often ignored.
Member Since: August 10, 2007 Posts: 0 Comments: 3293
1812. Levi32
Quoting Levi32:


It already looks like it is aiding his western poleward outflow channel. The GFS shows it slowly giving way to Isaac's westward progress, but it is possible some light southerly shear could be imparted on Isaac while he is interacting with the greater Antilles, aided by a sharp 200mb trough over the eastern gulf during that time.



Big problems could await once that sharp trough splits away and a piece retrogrades into the western gulf. Look at the ridging that blows up near and east of Florida over the general storm area. That's a classic ventilation pattern.

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Much more reasonable forecast from the NHC this time-around...
Member Since: October 3, 2010 Posts: 40 Comments: 4129
Quoting HurricaneDean07:
CONE SHIFTED WESTWARD EVEN MORE.


I expect it to continue to shift west
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WOW! Even TK and Aubie are here tonight.
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1808. auburn (Mod)
Quoting StormJunkie:


Just for the record, I would go as far as to consider MLC a personal friend. Just because we are debating the system does not mean anyone is trying to one up anyone. I am all about being proven wrong, because it will mean I have learned something. But only if I am proven wrong with evidence and understand what I am seeing in that evidence. So if you consider trying to learn a bad thing somehow, well I don't know what to tell you because I won't apologize for it.
tkeith and Aub, great to see y'all!


I am just here trying to learn..you guys all amaze me..
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Quoting HurricaneDean07:
CONE SHIFTED WESTWARD EVEN MORE.



THE MODEL CONSENSUS HAS SHIFTED A BIT TO THE RIGHT DURING THE FIRST HALF OF THE FORECAST PERIOD...PRIMARILY DUE TO AN EASTWARD SHIFT OF THE LATEST GFS TRACK. THE OFFICIAL FORECAST IS NUDGED A BIT TO THE RIGHT OF THE PREVIOUS ONE AND IS SOMEWHAT FASTER BASED ON THE LATEST MODEL GUIDANCE.

No it didn't. Right is East in this case
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As expected:

THE MODEL CONSENSUS HAS SHIFTED A BIT TO THE RIGHT DURING THE FIRST HALF OF THE FORECAST PERIOD...PRIMARILY DUE TO AN EASTWARD SHIFT OF THE LATEST GFS TRACK. THE OFFICIAL FORECAST IS NUDGED A BIT TO THE RIGHT OF THE PREVIOUS ONE AND IS SOMEWHAT FASTER BASED ON THE LATEST MODEL GUIDANCE.
Member Since: July 31, 2006 Posts: 56 Comments: 8112
On visible wide atlatic view or even better the water vapor view there is a 1019 high in the No. Gulf. Click on ncep fronts to see it. Is 1019 not strong enough to block Isaac? Or if it is, why does he not go under and west, like so many storms do. Or is it not a factor? Looks kind of what pushed Debby east. instead of west or even north.

Edit: I think the NHC just answered my question. That is the ridge that is suppose to break down. I get it now. I think.
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CONE SHIFTED WESTWARD EVEN MORE.

Member Since: October 3, 2010 Posts: 40 Comments: 4129
1803. Levi32
Quoting Chicklit:

Could this ventilate Isaac?


It already looks like it is aiding his western poleward outflow channel. The GFS shows the Cuban trough slowly giving way to Isaac's westward progress, but it is possible some light southerly shear could be imparted on Isaac while he is interacting with the greater Antilles, aided by a sharp 200mb trough over the eastern gulf during that time.

48 hours out 200mb:

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SYNOPTIC SURVEILLANCE MISSION BY THE NOAA G-IV JET AIRCRAFT HAS
BEEN CONDUCTED TO COLLECT ATMOSPHERIC OBSERVATIONS IN THE
LARGE-SCALE ENVIRONMENT OF ISAAC. THESE DATA WILL BE ASSIMILATED
INTO THE 0000 UTC RUNS OF THE GLOBAL MODELS...AND SHOULD IMPROVE
THE ACCURACY OF THEIR FORECASTS FOR THE NEXT ADVISORY CYCLE.
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Quoting tkeith:
It's nice to see alot of familiar "faces" when I check out WU for an update :)

Hi Keith, Hi Aubie,

Slow going with this storm. Glad it can't get it together, but you know guys they are so unorganized :))
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Not Florida anymore.

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Quoting oceanspringsMS:
"MLC, last night I was completely on board with a system that had zero alignment through the levels. That said, currently the P-3D has been through a 5k' & 10k' pass and found centers in basically the same position (give or take 20 miles or so, but not the 100 miles from last night). The mid level circulation is certainly broader than the low level. That coupled with the Microwave pass, it just seems obvious that the center is north of 16.

The center seems to be exactly where this image implies it is."

Early to mid 90's this use to be a place where you could get some good basic knowledje on a ts/hur coming your way. Now it appears to be all about how can I one up you and throw out as much tech BS as possiable. I least they still have a good conslidation of Sat and radar.


Just for the record, I would go as far as to consider MLC a personal friend. Just because we are debating the system does not mean anyone is trying to one up anyone. I am all about being proven wrong, because it will mean I have learned something. But only if I am proven wrong with evidence and understand what I am seeing in that evidence. So if you consider trying to learn a bad thing somehow, well I don't know what to tell you because I won't apologize for it.
tkeith and Aub, great to see y'all!
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OBSERVATIONS FROM A NOAA HURRICANE HUNTER AIRCRAFT SUGGEST THAT
ISAAC HAS STRENGTHENED ONLY SLIGHTLY THIS EVENING. FLIGHT-LEVEL
AND SFMR-OBSERVED SURFACE WINDS FROM THE AIRCRAFT SUGGEST THAT THE
CURRENT INTENSITY IS NEAR 40 KT. THE STORM CONTINUES TO HAVE
FAIRLY STRONG UPPER-LEVEL OUTFLOW AND...IF THE INNER CORE BECOMES
BETTER DEFINED...HAS AN OPPORTUNITY TO STRENGTHEN AS LONG AS IT
REMAINS OVER WATER. HOWEVER...THE CENTER OF THE STORM IS FORECAST
TO MOVE OVER SOUTHWESTERN HISPANIOLA IN 12 HOURS OR SO...AND THIS
WOULD HALT ANY INTENSIFICATION. A LITTLE LATER ON...LAND
INTERACTIONS WITH EASTERN CUBA WOULD ALSO INHIBIT INTENSIFICATION
OR CAUSE WEAKENING. ISAAC WILL LIKELY RESTRENGTHEN WHEN IT MOVES
OVER THE STRAITS OF FLORIDA AND THE EASTERN GULF OF MEXICO IN THE
LATTER PART OF THE FORECAST PERIOD. HOWEVER IT SHOULD BE NOTED
THAT THERE IS SIGNIFICANT UNCERTAINTY IN TROPICAL CYCLONE INTENSITY
PREDICTIONS AT 3-5 DAYS.

THE INITIAL MOTION ESTIMATE IS 290/16. A MID-TROPOSPHERIC TROUGH
OVER THE SOUTHEASTERN U.S. IS CAUSING A BREAK IN THE SUBTROPICAL
RIDGE. IN RESPONSE TO THIS...ISAAC SHOULD TURN TOWARD A MORE
NORTHWESTWARD HEADING OVER THE NEXT FEW DAYS. THE MODEL CONSENSUS
HAS SHIFTED A BIT TO THE RIGHT DURING THE FIRST HALF OF THE FORECAST
PERIOD...PRIMARILY DUE TO AN EASTWARD SHIFT OF THE LATEST GFS
TRACK. THE OFFICIAL FORECAST IS NUDGED A BIT TO THE RIGHT OF
THE PREVIOUS ONE AND IS SOMEWHAT FASTER BASED ON THE LATEST MODEL
GUIDANCE.

THE INITIAL AND FORECAST WIND RADII HAVE BEEN EXPANDED BASED ON BUOY
AND SHIP DATA. IT IS IMPORTANT NOT TO FOCUS ON THE EXACT TRACK
BECAUSE OF FORECAST UNCERTAINTIES AND THE FACT THAT ISAAC HAS A
LARGE AREA OF TROPICAL STORM FORCE WINDS ASSOCIATED WITH IT.

A SYNOPTIC SURVEILLANCE MISSION BY THE NOAA G-IV JET AIRCRAFT HAS
BEEN CONDUCTED TO COLLECT ATMOSPHERIC OBSERVATIONS IN THE
LARGE-SCALE ENVIRONMENT OF ISAAC. THESE DATA WILL BE ASSIMILATED
INTO THE 0000 UTC RUNS OF THE GLOBAL MODELS...AND SHOULD IMPROVE
THE ACCURACY OF THEIR FORECASTS FOR THE NEXT ADVISORY CYCLE.

FORECAST POSITIONS AND MAX WINDS

INIT 24/0300Z 16.7N 68.7W 40 KT 45 MPH
12H 24/1200Z 17.5N 70.7W 55 KT 65 MPH
24H 25/0000Z 18.8N 73.1W 45 KT 50 MPH
36H 25/1200Z 20.2N 75.4W 45 KT 50 MPH...INLAND
48H 26/0000Z 21.8N 77.7W 45 KT 50 MPH...INLAND
72H 27/0000Z 24.8N 82.0W 55 KT 65 MPH...OVER WATER
96H 28/0000Z 27.5N 85.5W 70 KT 80 MPH
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Tropical Storm ISAAC Public Advisory

Home Public Adv Fcst Adv Discussion Wind Probs Graphics Archive

US Watch/Warning

000
WTNT34 KNHC 240250
TCPAT4

BULLETIN
TROPICAL STORM ISAAC ADVISORY NUMBER 12
NWS NATIONAL HURRICANE CENTER MIAMI FL AL092012
1100 PM AST THU AUG 23 2012

...ISAAC EXPECTED TO BE NEAR OR OVER HISPANIOLA TOMORROW ALONG WITH
HEAVY RAINS AND FLOODING...


SUMMARY OF 1100 PM AST...0300 UTC...INFORMATION
-----------------------------------------------
LOCATION...16.7N 68.7W
ABOUT 145 MI...235 KM SSE OF SANTO DOMINGO DOMINICAN REPUBLIC
MAXIMUM SUSTAINED WINDS...45 MPH...75 KM/H
PRESENT MOVEMENT...WNW OR 290 DEGREES AT 18 MPH...30 KM/H
MINIMUM CENTRAL PRESSURE...1001 MB...29.56 INCHES


WATCHES AND WARNINGS
--------------------
CHANGES WITH THIS ADVISORY...

THE HURRICANE WARNING FOR HAITI HAS BEEN CHANGED TO A TROPICAL STORM
WARNING AND A HURRICANE WATCH.

THE GOVERNMENT OF CUBA HAS ISSUED A TROPICAL STORM WARNING FOR THE
CUBAN PROVINCES OF CAMAGUEY...LAS TUNAS...GRANMA...HOLGUIN...
SANTIAGO DE CUBA...AND GUANTANAMO.

THE GOVERNMENT OF CUBA HAS ISSUED A TROPICAL STORM WATCH FOR THE
CUBAN PROVINCES OF CIEGO DE AVILA...SANCTI SPIRITUS...AND VILLA
CLARA.

THE TROPICAL STORM WARNINGS FOR PUERTO RICO...VIEQUES...CULEBRA...
AND THE U.S. VIRGIN ISLANDS HAVE BEEN DISCONTINUED.

THE GOVERNMENT OF ANTIGUA AND BARBUDA HAS DISCONTINUED THE TROPICAL
STORM WARNING FOR THE BRITISH VIRGIN ISLANDS.

THE GOVERNMENT OF THE BAHAMAS HAS ISSUED A TROPICAL STORM WATCH FOR
ANDROS ISLAND AND THE CENTRAL BAHAMAS INCLUDING CAT ISLAND...THE
EXUMAS...LONG ISLAND...RUM CAY...AND SAN SALVADOR.

SUMMARY OF WATCHES AND WARNINGS IN EFFECT...

A HURRICANE WATCH IS IN EFFECT FOR...
* HAITI

A TROPICAL STORM WARNING IS IN EFFECT FOR...
* DOMINICAN REPUBLIC
* HAITI
* CUBAN PROVINCES OF CAMAGUEY...LAS TUNAS...GRANMA...HOLGUIN...
SANTIAGO DE CUBA...AND GUANTANAMO
* SOUTHEASTERN BAHAMAS INCLUDING THE ACKLINS...CROOKED ISLAND...LONG
CAY...THE INAGUAS...MAYAGUANA...AND THE RAGGED ISLANDS
* TURKS AND CAICOS ISLANDS

A TROPICAL STORM WATCH IS IN EFFECT FOR...
* CUBAN PROVINCES OF CIEGO DE AVILA...SANCTI SPIRITUS...AND VILLA
CLARA
* ANDROS ISLAND AND THE CENTRAL BAHAMAS INCLUDING CAT ISLAND...THE
EXUMAS...LONG ISLAND...RUM CAY...AND SAN SALVADOR

A HURRICANE WATCH MEANS THAT HURRICANE CONDITIONS ARE POSSIBLE
WITHIN THE WATCH AREA...IN THIS CASE WITHIN THE NEXT 24 TO 36 HOURS.

A TROPICAL STORM WARNING MEANS THAT TROPICAL STORM CONDITIONS ARE
EXPECTED SOMEWHERE WITHIN THE WARNING AREA WITHIN 36 HOURS.

A TROPICAL STORM WATCH MEANS THAT TROPICAL STORM CONDITIONS ARE
POSSIBLE WITHIN THE WATCH AREA...GENERALLY WITHIN 48 HOURS.

INTERESTS IN JAMAICA...THE REMAINDER OF CUBA...THE REMAINDER OF THE
BAHAMAS...SOUTH FLORIDA...AND THE FLORIDA KEYS SHOULD MONITOR THE
PROGRESS OF ISAAC.

FOR STORM INFORMATION SPECIFIC TO YOUR AREA IN THE UNITED STATES...
INCLUDING POSSIBLE INLAND WATCHES AND WARNINGS...PLEASE MONITOR
PRODUCTS ISSUED BY YOUR LOCAL NATIONAL WEATHER SERVICE FORECAST
OFFICE. FOR STORM INFORMATION SPECIFIC TO YOUR AREA OUTSIDE THE
UNITED STATES...PLEASE MONITOR PRODUCTS ISSUED BY YOUR NATIONAL
METEOROLOGICAL SERVICE.


DISCUSSION AND 48-HOUR OUTLOOK
------------------------------
AT 1100 PM AST...0300 UTC...THE CENTER OF TROPICAL STORM ISAAC WAS
LOCATED NEAR LATITUDE 16.7 NORTH...LONGITUDE 68.7 WEST. ISAAC IS
MOVING TOWARD THE WEST-NORTHWEST NEAR 18 MPH...30 KM/H...AND A
WEST-NORTHWEST TO NORTHWEST MOTION AT A SLIGHTLY SLOWER FORWARD
SPEED IS EXPECTED OVER THE NEXT COUPLE OF DAYS. ON THE FORECAST
TRACK...THE CENTER OF ISAAC WILL BE NEAR OR OVER HISPANIOLA ON
FRIDAY...AND MOVE NEAR OR OVER SOUTHEASTERN CUBA ON SATURDAY.

MAXIMUM SUSTAINED WINDS ARE NEAR 45 MPH...75 KM/H...WITH HIGHER
GUSTS. SOME STRENGTHENING IS FORECAST WHILE THE CENTER REMAINS OVER
WATER.

TROPICAL STORM FORCE WINDS EXTEND OUTWARD UP TO 185 MILES...295 KM
FROM THE CENTER.

ESTIMATED MINIMUM CENTRAL PRESSURE IS 1001 MB...29.56 INCHES.


HAZARDS AFFECTING LAND
----------------------
WIND...TROPICAL STORM CONDITIONS ARE EXPECTED OVER PORTIONS OF THE
DOMINICAN REPUBLIC AND HAITI ON FRIDAY...WITH HURRICANE CONDITIONS
POSSIBLE OVER PORTIONS OF HAITI. TROPICAL STORM CONDITIONS ARE
EXPECTED OVER THE SOUTHEASTERN BAHAMAS AND THE TURKS AND CAICOS
ISLANDS BY LATE FRIDAY. TROPICAL STORM CONDITIONS ARE EXPECTED
OVER EASTERN CUBA BY LATE FRIDAY OR EARLY SATURDAY. TROPICAL STORM
CONDITIONS ARE POSSIBLE OVER CENTRAL CUBA...THE CENTRAL BAHAMAS...
AND ANDROS ISLAND BY SATURDAY.

RAINFALL...TOTAL RAINFALL ACCUMULATIONS OF 8 TO 12 INCHES...WITH
MAXIMUM AMOUNTS OF 20 INCHES...ARE POSSIBLE OVER HISPANIOLA. THESE
RAINS COULD CAUSE LIFE-THREATENING FLASH FLOODS AND MUD SLIDES.
TOTAL RAIN ACCUMULATIONS OF 2 TO 4 INCHES...WITH MAXIMUM AMOUNTS OF
6 INCHES OVER HIGHER TERRAIN...ARE POSSIBLE OVER PUERTO RICO AND
THE VIRGIN ISLANDS. TOTAL RAIN ACCUMULATIONS OF 2 TO 4 INCHES ARE
POSSIBLE OVER THE SOUTHEASTERN BAHAMAS.

STORM SURGE...A STORM SURGE WILL RAISE WATER LEVELS BY AS MUCH AS 2
TO 4 FEET ABOVE NORMAL TIDE LEVELS IN AREAS OF ONSHORE WINDS ALONG
THE COAST OF HISPANIOLA. NEAR THE COAST...THE SURGE WILL BE
ACCOMPANIED BY DANGEROUS WAVES. A STORM SURGE WILL RAISE WATER
LEVELS BY AS MUCH AS 1 TO 3 FEET ABOVE NORMAL TIDE LEVELS IN AREAS
OF ONSHORE WINDS ALONG THE COAST WITHIN THE REMAINING TROPICAL
STORM WARNING AREA.

SURF...DANGEROUS SURF AND RIP CURRENT CONDITIONS WILL AFFECT THE
LEEWARD ISLANDS...VIRGIN ISLANDS...PUERTO RICO...HISPANIOLA...THE
SOUTHEASTERN BAHAMAS...AND THE TURKS AND CAICOS DURING THE NEXT
COUPLE OF DAYS. PLEASE CONSULT PRODUCTS FROM YOUR LOCAL WEATHER
OFFICE FOR MORE INFORMATION.


NEXT ADVISORY
-------------
NEXT INTERMEDIATE ADVISORY...200 AM AST.
NEXT COMPLETE ADVISORY...500 AM AST.

$$
FORECASTER PASCH
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Quoting pcola57:



Wow ! If that plays out with 40-50mph of wind shear like that map shows(post 1684) that may be a blessing Chicklit..hope it's not a "mistake" on the mapping dept.. :)
This is about the 5th time this has been asked,"what's this forecasted shear going to do?".I don't believe anyone has responded to the question yet.
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Quoting Levi32:


That feature is quickly fading as an influence in the mid-level steering layer. It seems to get integrated into the western part of Isaac's circulation as it swings northwestward on its eastern side on the model runs.



levi were do you think the center is seems like everyone has an opinion here
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Double typhoons on course to slam China: six storms since the start of August
Posted on August 23, 2012

August 23, 2012 – CHINA – Two powerful typhoons are heading toward China, putting the weather-beaten nation on alert again after four storms have caused landfalls across the country since the start of August. Typhoons Tembin and Bolaven may have a combined impact on coastal areas in the coming 10 days,” Zhang Chang’an, chief forecaster at the China Meteorological Administration, said on Wednesday. Both storms are strengthening, with Bolaven expected to be the strongest typhoon to hit China this year if it lands in the country, Zhang said, adding that the storm will bring maximum winds of 220 km/h. The National Commission on Disaster Reduction issued a typhoon alert on Wednesday, warning authorities to make emergency plans. Tembin was about 2,000 km from the coast of Zhejiang province on Wednesday, moving at a speed of 5 km/h. The administration has asked authorities in potential affected areas to set up warning signs in high-risk areas such as construction sites and low-lying areas, and open emergency shelters including schools and stadiums for evacuation of affected people. The Fujian Meteorological Bureau urged boats to take shelter in ports by Wednesday to avoid possible damage brought by Tembin. –China Daily
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What if we get up to a Cat 1
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1792. Levi32
Quoting StormJunkie:
On the latest P-3D, they showed the center back down near 16N. This image is centered on 16N. Do not imply anything by this statement, but the center seems to be right where the hole is in the deep burst of convection.



The 700mb center, that is. Still not stacked in my opinion.
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1790. MahFL
Wow.

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Quoting Levi32:


That feature is quickly fading as an influence in the mid-level steering layer. It seems to get integrated into the western part of Isaac's circulation as it swings northwestward on its eastern side on the model runs.

Could this ventilate Isaac?
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I think the important thing to remember now is that Isaac is five days out from landfall (if it made landfall on the upper Gulf Coast), and this is an especially uncertain situation right now because of model divergance.

All the news and Weather Channel are doing right now is saying, "RIGHT NOW the storm has decreased in speed, RIGHT NOW the center is relocating, RIGHT NOW it is starting to move WNW, RIGHT NOW it looks like it will make landfall here, and maybe here, and here, or possibly there.

The point is, there is no need for anyone to get riled up about a specific landfall point forecasted by one computer model or weather forecaster. What people should do now is do what they have done in years past when the news and TWC weren't hyping things all the way in the Eastern Caribbean, if they are in the cone's path or close to it, go over your hurricane plan, and make sure you know what to do and where you might go on Tuesday (or sometime around then).

Virtually any (at least it seems to me) part of the Gulf Coast could be affected right now. It's just a matter of time before we have at least a general area to be more concerned about.

The point is we just don't really know WHERE. We know the "general" portion of the world this is going to happen, and all we need to do is wait a couple or more days until we should start naming cities that are really under the gun.

And this is not to say we should abandon focusing on models and such for now, it is always important to follow the latest information, but not treat every bit of it as "gospel."

Thank you,
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1787. tkeith
Quoting KoritheMan:


Shoulda known Isaac would drag you over here. ;)

How you doin Keith?
There's a "Hebert Box" lurkin around somewhere in Issacs path...

Not superstitious, but I looked for a four leaf clover today...didn't find one :)
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I know the barbs are missing from the center pass. But this is what recon is finding at 10k...

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Quoting WXGulfBreeze:


I want some of what you're smokin'.


Euro, gfdl, hrwf smoking what I'm smoking chief
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Quoting Levi32:


The result of a clash between Isaac's outflow on the western side with an old upper trough over eastern Cuba.


Is this going to effect Isaac?
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1783. Levi32
Quoting sunlinepr:


Levi, is that ULL over E Cuba dissipating, then if it happens, Ernesto will go along to the WNW?


That feature is quickly fading as an influence in the mid-level steering layer. It seems to get integrated into the western part of Isaac's circulation as it swings northwestward on its eastern side on the model runs.
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1781. auburn (Mod)
Quoting tkeith:
It's nice to see alot of familiar "faces" when I check out WU for an update :)


Yea me too..MLC and SJ and so many more..nice to see you all!
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1780. centex
Quoting StormJunkie:
On the latest P-3D, they showed the center back down near 16N. This image is centered on 16N. Do not imply anything by this statement, but the center seems to be right where the hole is in the deep burst of convection.

I'm fine with that except that convection and hole is still only a small part of over all system. The LL center is not very robust compared to mid level.
Member Since: August 10, 2007 Posts: 0 Comments: 3293
Quoting WXGulfBreeze:


I want some of what you're smokin'.



An thinking strong cat 4 or low cat 5
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Quoting Tribucanes:
If tonight is the night Isaac gets his act together and a well-defined center forms; will we be looking at RI to hurricane strength tomorrow likely? Isaac looks like he's gotten angry compared to just a few hours ago. Deep blood reds have taken over in his presentation. Isaac's going to be the storm of the year it's starting to look like big time. Strong cat1, weak cat2 hitting the Alabama coast/Panhandle starting to look like a best case option for Isaac's path at this point. Not good at all, to say the least.

I would say anything is possible.
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This is the most confusing organization process I've watched in a storm since pre-Alex.

The convection on the W. third of the storm is intensifying and moving W faster than the NHC forecast track speed.

The convection S of the storm, except a dry line, has greatly intensified into a gigantic feeder band, which is some of the strongest weather visible on any radar presently.




The rain band ESE of PR is stronger than any weather they've received so far.

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Quoting brazocane:
Ok not to stray off the Main topic at hand, but does anyone else find the Blob in the Western Gulf the very least bit interesting?(I'm not trying to be that guy) Its been fairly persistent now:



Yes. This bugs me.
Member Since: July 9, 2006 Posts: 184 Comments: 29610
Quoting tkeith:
It's nice to see alot of familiar "faces" when I check out WU for an update :)


Shoulda known Isaac would drag you over here. ;)

How you doin Keith?
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Jeff co-founded the Weather Underground in 1995 while working on his Ph.D. He flew with the NOAA Hurricane Hunters from 1986-1990.

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