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Tropical Depression Isaac:
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biggerbyte
- Posts: 1142
- Joined: Thu Feb 04, 2010 12:15 am
- Location: Porter, Texas. (Montgomery County)
- Contact:
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Portastorm
- Posts: 800
- Joined: Wed Feb 03, 2010 3:04 pm
- Location: Southwest Austin/Oak Hill, TX
- Contact:
Looks like the folks at HGX are going with the Euro on their forecast and not the GFS ...
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HOUSTON/GALVESTON TX
326 PM CDT SUN AUG 26 2012
.DISCUSSION...
SCATTERED SHRA/TSRA CONTINUE OVER MAINLY THE WESTERN HALF OF
SOUTHEAST TEXAS ALONG A WEAK LOW LEVEL CONVERGENCE ZONE. A WEAK
BOUNDARY WILL APPROACH THE NORTHERN THIRD OF SE TX ON MONDAY AND
PW VALUES INCREASE TO AROUND 2.0 INCHES SO WILL CARRY CHANCE POPS
OVER THE EXTREME NORTH AND SLIGHT CHANCE POPS FURTHER SOUTH. THE
GFS IS MORE AGGRESSIVE THAN THE NAM BUT BOTH MODELS HINT AT PRECIP
OVER THE NORTH. LATEST PROGS DRY THINGS OUT ON TUESDAY WITH PW
VALUES FALLING TO AROUND 1.6 INCHES. THE HIGHER MOISTURE LEVELS
WILL BE OVER THE WESTERN ZONES AND DAYTIME HEATING WILL STILL
TRIGGER ISOLATED SHRA/TSRA DURING THE AFTN. CONVECTIVE TEMPS ON
TUESDAY ARE CONSIDERABLY WARMER...AROUND 92-94 DEGREES.
LONG RANGE MODELS DIFFER RATHER SIGNIFICANTLY ON WEDNESDAY AND
BEYOND. THE CANADIAN...ECMWF AND UKMET ALL TAKE ISAAC TOWARD THE
NORTHERN GULF COAST...AND THEN NORTHWARD AWAY FROM TEXAS. THE GFS
IS AN OUTLIER AND TAKES THE STORM TOWARD LOUISIANA AND THEN SLOWLY
MOVES THE STORM INTO TEXAS. A MID LATITUDE TROUGH CROSSING THE
EASTERN U.S. SHOULD BE STRONG ENOUGH TO PULL THE SYSTEM NORTHWARD.
CURRENT TPC TRACK TAKES THE STORM TOWARD THE MISSISSIPPI COAST.
WILL LEAN HEAVILY TOWARD THE ECMWF SOLUTION MID WEEK AND BEYOND.
THIS MEANS ABOVE NORMAL TEMPERATURES AND RELATIVELY LOW DEW PTS.
IN FACT...THE ECMWF DEW PTS DROP INTO THE LOWER 50S ON THURSDAY.
FEEL A LARGE DIURNAL SPREAD IN TEMPERATURES WILL BE POSSIBLE DUE
TO THE DRY AIR IN PLACE ON THE WEST SIDE OF ISAAC. IF THE GFS IS
CORRECT...THE FORECAST WILL UNDERGO SIGNIFICANT CHANGES WITH
HIGHER RAIN CHANCES ON THURSDAY. AGAIN...AT THIS TIME...THE GFS IS
THE OUTLIER AND HOPEFULLY A CONSENSUS WILL BUILD LATER TONIGHT.
A WEAKNESS ALOFT WILL DEVELOP OVER THE WEEKEND AND MOISTURE LEVELS
BRIEFLY INCREASE. WILL ADD 20 POPS FOR BOTH SAT/SUN. TEMPS WILL
TREND SLIGHTLY COOLER NEXT WEEKEND WITH MORE CLOUD COVER AND LOWER
HEIGHTS.
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HOUSTON/GALVESTON TX
326 PM CDT SUN AUG 26 2012
.DISCUSSION...
SCATTERED SHRA/TSRA CONTINUE OVER MAINLY THE WESTERN HALF OF
SOUTHEAST TEXAS ALONG A WEAK LOW LEVEL CONVERGENCE ZONE. A WEAK
BOUNDARY WILL APPROACH THE NORTHERN THIRD OF SE TX ON MONDAY AND
PW VALUES INCREASE TO AROUND 2.0 INCHES SO WILL CARRY CHANCE POPS
OVER THE EXTREME NORTH AND SLIGHT CHANCE POPS FURTHER SOUTH. THE
GFS IS MORE AGGRESSIVE THAN THE NAM BUT BOTH MODELS HINT AT PRECIP
OVER THE NORTH. LATEST PROGS DRY THINGS OUT ON TUESDAY WITH PW
VALUES FALLING TO AROUND 1.6 INCHES. THE HIGHER MOISTURE LEVELS
WILL BE OVER THE WESTERN ZONES AND DAYTIME HEATING WILL STILL
TRIGGER ISOLATED SHRA/TSRA DURING THE AFTN. CONVECTIVE TEMPS ON
TUESDAY ARE CONSIDERABLY WARMER...AROUND 92-94 DEGREES.
LONG RANGE MODELS DIFFER RATHER SIGNIFICANTLY ON WEDNESDAY AND
BEYOND. THE CANADIAN...ECMWF AND UKMET ALL TAKE ISAAC TOWARD THE
NORTHERN GULF COAST...AND THEN NORTHWARD AWAY FROM TEXAS. THE GFS
IS AN OUTLIER AND TAKES THE STORM TOWARD LOUISIANA AND THEN SLOWLY
MOVES THE STORM INTO TEXAS. A MID LATITUDE TROUGH CROSSING THE
EASTERN U.S. SHOULD BE STRONG ENOUGH TO PULL THE SYSTEM NORTHWARD.
CURRENT TPC TRACK TAKES THE STORM TOWARD THE MISSISSIPPI COAST.
WILL LEAN HEAVILY TOWARD THE ECMWF SOLUTION MID WEEK AND BEYOND.
THIS MEANS ABOVE NORMAL TEMPERATURES AND RELATIVELY LOW DEW PTS.
IN FACT...THE ECMWF DEW PTS DROP INTO THE LOWER 50S ON THURSDAY.
FEEL A LARGE DIURNAL SPREAD IN TEMPERATURES WILL BE POSSIBLE DUE
TO THE DRY AIR IN PLACE ON THE WEST SIDE OF ISAAC. IF THE GFS IS
CORRECT...THE FORECAST WILL UNDERGO SIGNIFICANT CHANGES WITH
HIGHER RAIN CHANCES ON THURSDAY. AGAIN...AT THIS TIME...THE GFS IS
THE OUTLIER AND HOPEFULLY A CONSENSUS WILL BUILD LATER TONIGHT.
A WEAKNESS ALOFT WILL DEVELOP OVER THE WEEKEND AND MOISTURE LEVELS
BRIEFLY INCREASE. WILL ADD 20 POPS FOR BOTH SAT/SUN. TEMPS WILL
TREND SLIGHTLY COOLER NEXT WEEKEND WITH MORE CLOUD COVER AND LOWER
HEIGHTS.
on the water vapor loop look at circulation by Bay of Campeche. can this cause a different path? just wondering
Last edited by skidog40 on Sun Aug 26, 2012 4:30 pm, edited 1 time in total.
-
srainhoutx
- Site Admin
- Posts: 19622
- Joined: Tue Feb 02, 2010 2:32 pm
- Location: Maggie Valley, NC
- Contact:
TROPICAL STORM ISAAC FORECAST/ADVISORY NUMBER 23
NWS NATIONAL HURRICANE CENTER MIAMI FL AL092012
2100 UTC SUN AUG 26 2012
CHANGES IN WATCHES AND WARNINGS WITH THIS ADVISORY...
THE GOVERNMENT OF THE BAHAMAS HAS DISCONTINUED THE TROPICAL STORM
WARNING FOR THE NORTHWESTERN BAHAMAS.
THE GOVERNMENT OF CUBA HAS DISCONTINUED ALL WATCHES AND WARNINGS.
THE TROPICAL STORM WATCH FROM NORTH OF SEBASTIAN INLET TO FLAGLER
BEACH IS DISCONTINUED.
THE HURRICANE WARNING IS CHANGED TO A TROPICAL STORM WARNING FOR THE
FLORIDA KEYS INCLUDING THE DRY TORTUGAS AND FLORIDA BAY.
THE HURRICANE WARNING FOR THE WEST COAST OF FLORIDA FROM BONITA
BEACH SOUTHWARD TO OCEAN REEF IS CHANGED TO A TROPICAL STORM
WARNING.
THE HURRICANE WATCH IS CHANGED TO A HURRICANE WARNING FOR THE
NORTHERN GULF OF MEXICO COAST FROM EAST OF MORGAN CITY LOUSIANA TO
DESTIN FLORIDA...INCLUDING METROPOLITAN NEW ORLEANS...LAKE
PONTCHARTRAIN...AND LAKE MAUREPAS.
THE TROPICAL STORM WARNING FROM SUWANNEE RIVER TO ANCLOTE KEY IS
DISCONTINUED.
SUMMARY OF WATCHES AND WARNINGS IN EFFECT...
A HURRICANE WARNING IS IN EFFECT FOR...
* EAST OF MORGAN CITY LOUISIANA TO DESTIN FLORIDA...INCLUDING
METROPOLITAN NEW ORLEANS...LAKE PONTCHARTRAIN...AND LAKE MAUREPAS
A HURRICANE WATCH IS IN EFFECT FOR...
* EAST OF DESTIN TO INDIAN PASS FLORIDA
A TROPICAL STORM WARNING IS IN EFFECT FOR...
* THE FLORIDA PENINSULA FROM SEBASTIAN INLET SOUTHWARD ON THE EAST
COAST AND FROM ANCLOTE KEY SOUTHWARD ON THE WEST COAST.
* FLORIDA KEYS...INCLUDING THE DRY TORTUGAS AND FLORIDA BAY
* LAKE OKEECHOBEE
A HURRICANE WARNING MEANS THAT HURRICANE CONDITIONS ARE EXPECTED
SOMEWHERE WITHIN THE WARNING AREA...IN THIS CASE WITHIN THE NEXT 24
HOURS. PREPARATIONS TO PROTECT LIFE AND PROPERTY SHOULD BE RUSHED
TO COMPLETION.
A HURRICANE WATCH MEANS THAT HURRICANE CONDITIONS ARE POSSIBLE
WITHIN THE WATCH AREA. A WATCH IS TYPICALLY ISSUED 48 HOURS
BEFORE THE ANTICIPATED FIRST OCCURRENCE OF TROPICAL-STORM-FORCE
WINDS...CONDITIONS THAT MAKE OUTSIDE PREPARATIONS DIFFICULT OR
DANGEROUS.
A TROPICAL STORM WARNING MEANS THAT TROPICAL STORM CONDITIONS ARE
EXPECTED SOMEWHERE WITHIN THE WARNING AREA WITHIN 36 HOURS.
TROPICAL STORM CENTER LOCATED NEAR 24.2N 82.3W AT 26/2100Z
POSITION ACCURATE WITHIN 25 NM
PRESENT MOVEMENT TOWARD THE WEST-NORTHWEST OR 295 DEGREES AT 14 KT
ESTIMATED MINIMUM CENTRAL PRESSURE 994 MB
MAX SUSTAINED WINDS 50 KT WITH GUSTS TO 60 KT.
50 KT....... 60NE 0SE 0SW 60NW.
34 KT.......180NE 120SE 80SW 180NW.
12 FT SEAS..150NE 150SE 120SW 120NW.
WINDS AND SEAS VARY GREATLY IN EACH QUADRANT. RADII IN NAUTICAL
MILES ARE THE LARGEST RADII EXPECTED ANYWHERE IN THAT QUADRANT.
REPEAT...CENTER LOCATED NEAR 24.2N 82.3W AT 26/2100Z
AT 26/1800Z CENTER WAS LOCATED NEAR 23.9N 81.5W
FORECAST VALID 27/0600Z 25.1N 83.9W
MAX WIND 55 KT...GUSTS 65 KT.
50 KT... 60NE 0SE 0SW 60NW.
34 KT...180NE 120SE 80SW 180NW.
FORECAST VALID 27/1800Z 26.3N 85.9W
MAX WIND 60 KT...GUSTS 75 KT.
50 KT... 60NE 0SE 0SW 60NW.
34 KT...180NE 120SE 80SW 180NW.
FORECAST VALID 28/0600Z 27.7N 87.6W
MAX WIND 70 KT...GUSTS 85 KT.
64 KT... 30NE 20SE 10SW 20NW.
50 KT... 60NE 60SE 40SW 50NW.
34 KT...180NE 150SE 80SW 160NW.
FORECAST VALID 28/1800Z 28.9N 88.5W
MAX WIND 80 KT...GUSTS 100 KT.
50 KT... 70NE 60SE 50SW 60NW.
34 KT...180NE 150SE 90SW 160NW.
FORECAST VALID 29/1800Z 30.7N 89.5W
MAX WIND 85 KT...GUSTS 105 KT.
50 KT... 60NE 70SE 60SW 40NW.
34 KT...100NE 150SE 100SW 90NW.
EXTENDED OUTLOOK. NOTE...ERRORS FOR TRACK HAVE AVERAGED NEAR 175 NM
ON DAY 4 AND 225 NM ON DAY 5...AND FOR INTENSITY NEAR 20 KT EACH DAY
OUTLOOK VALID 30/1800Z 32.5N 90.0W...INLAND
MAX WIND 30 KT...GUSTS 40 KT.
OUTLOOK VALID 31/1800Z 34.5N 90.0W...INLAND
MAX WIND 20 KT...GUSTS 30 KT.
REQUEST FOR 3 HOURLY SHIP REPORTS WITHIN 300 MILES OF 24.2N 82.3W
NEXT ADVISORY AT 27/0300Z
$$
FORECASTER PASCH
NWS NATIONAL HURRICANE CENTER MIAMI FL AL092012
2100 UTC SUN AUG 26 2012
CHANGES IN WATCHES AND WARNINGS WITH THIS ADVISORY...
THE GOVERNMENT OF THE BAHAMAS HAS DISCONTINUED THE TROPICAL STORM
WARNING FOR THE NORTHWESTERN BAHAMAS.
THE GOVERNMENT OF CUBA HAS DISCONTINUED ALL WATCHES AND WARNINGS.
THE TROPICAL STORM WATCH FROM NORTH OF SEBASTIAN INLET TO FLAGLER
BEACH IS DISCONTINUED.
THE HURRICANE WARNING IS CHANGED TO A TROPICAL STORM WARNING FOR THE
FLORIDA KEYS INCLUDING THE DRY TORTUGAS AND FLORIDA BAY.
THE HURRICANE WARNING FOR THE WEST COAST OF FLORIDA FROM BONITA
BEACH SOUTHWARD TO OCEAN REEF IS CHANGED TO A TROPICAL STORM
WARNING.
THE HURRICANE WATCH IS CHANGED TO A HURRICANE WARNING FOR THE
NORTHERN GULF OF MEXICO COAST FROM EAST OF MORGAN CITY LOUSIANA TO
DESTIN FLORIDA...INCLUDING METROPOLITAN NEW ORLEANS...LAKE
PONTCHARTRAIN...AND LAKE MAUREPAS.
THE TROPICAL STORM WARNING FROM SUWANNEE RIVER TO ANCLOTE KEY IS
DISCONTINUED.
SUMMARY OF WATCHES AND WARNINGS IN EFFECT...
A HURRICANE WARNING IS IN EFFECT FOR...
* EAST OF MORGAN CITY LOUISIANA TO DESTIN FLORIDA...INCLUDING
METROPOLITAN NEW ORLEANS...LAKE PONTCHARTRAIN...AND LAKE MAUREPAS
A HURRICANE WATCH IS IN EFFECT FOR...
* EAST OF DESTIN TO INDIAN PASS FLORIDA
A TROPICAL STORM WARNING IS IN EFFECT FOR...
* THE FLORIDA PENINSULA FROM SEBASTIAN INLET SOUTHWARD ON THE EAST
COAST AND FROM ANCLOTE KEY SOUTHWARD ON THE WEST COAST.
* FLORIDA KEYS...INCLUDING THE DRY TORTUGAS AND FLORIDA BAY
* LAKE OKEECHOBEE
A HURRICANE WARNING MEANS THAT HURRICANE CONDITIONS ARE EXPECTED
SOMEWHERE WITHIN THE WARNING AREA...IN THIS CASE WITHIN THE NEXT 24
HOURS. PREPARATIONS TO PROTECT LIFE AND PROPERTY SHOULD BE RUSHED
TO COMPLETION.
A HURRICANE WATCH MEANS THAT HURRICANE CONDITIONS ARE POSSIBLE
WITHIN THE WATCH AREA. A WATCH IS TYPICALLY ISSUED 48 HOURS
BEFORE THE ANTICIPATED FIRST OCCURRENCE OF TROPICAL-STORM-FORCE
WINDS...CONDITIONS THAT MAKE OUTSIDE PREPARATIONS DIFFICULT OR
DANGEROUS.
A TROPICAL STORM WARNING MEANS THAT TROPICAL STORM CONDITIONS ARE
EXPECTED SOMEWHERE WITHIN THE WARNING AREA WITHIN 36 HOURS.
TROPICAL STORM CENTER LOCATED NEAR 24.2N 82.3W AT 26/2100Z
POSITION ACCURATE WITHIN 25 NM
PRESENT MOVEMENT TOWARD THE WEST-NORTHWEST OR 295 DEGREES AT 14 KT
ESTIMATED MINIMUM CENTRAL PRESSURE 994 MB
MAX SUSTAINED WINDS 50 KT WITH GUSTS TO 60 KT.
50 KT....... 60NE 0SE 0SW 60NW.
34 KT.......180NE 120SE 80SW 180NW.
12 FT SEAS..150NE 150SE 120SW 120NW.
WINDS AND SEAS VARY GREATLY IN EACH QUADRANT. RADII IN NAUTICAL
MILES ARE THE LARGEST RADII EXPECTED ANYWHERE IN THAT QUADRANT.
REPEAT...CENTER LOCATED NEAR 24.2N 82.3W AT 26/2100Z
AT 26/1800Z CENTER WAS LOCATED NEAR 23.9N 81.5W
FORECAST VALID 27/0600Z 25.1N 83.9W
MAX WIND 55 KT...GUSTS 65 KT.
50 KT... 60NE 0SE 0SW 60NW.
34 KT...180NE 120SE 80SW 180NW.
FORECAST VALID 27/1800Z 26.3N 85.9W
MAX WIND 60 KT...GUSTS 75 KT.
50 KT... 60NE 0SE 0SW 60NW.
34 KT...180NE 120SE 80SW 180NW.
FORECAST VALID 28/0600Z 27.7N 87.6W
MAX WIND 70 KT...GUSTS 85 KT.
64 KT... 30NE 20SE 10SW 20NW.
50 KT... 60NE 60SE 40SW 50NW.
34 KT...180NE 150SE 80SW 160NW.
FORECAST VALID 28/1800Z 28.9N 88.5W
MAX WIND 80 KT...GUSTS 100 KT.
50 KT... 70NE 60SE 50SW 60NW.
34 KT...180NE 150SE 90SW 160NW.
FORECAST VALID 29/1800Z 30.7N 89.5W
MAX WIND 85 KT...GUSTS 105 KT.
50 KT... 60NE 70SE 60SW 40NW.
34 KT...100NE 150SE 100SW 90NW.
EXTENDED OUTLOOK. NOTE...ERRORS FOR TRACK HAVE AVERAGED NEAR 175 NM
ON DAY 4 AND 225 NM ON DAY 5...AND FOR INTENSITY NEAR 20 KT EACH DAY
OUTLOOK VALID 30/1800Z 32.5N 90.0W...INLAND
MAX WIND 30 KT...GUSTS 40 KT.
OUTLOOK VALID 31/1800Z 34.5N 90.0W...INLAND
MAX WIND 20 KT...GUSTS 30 KT.
REQUEST FOR 3 HOURLY SHIP REPORTS WITHIN 300 MILES OF 24.2N 82.3W
NEXT ADVISORY AT 27/0300Z
$$
FORECASTER PASCH
Carla/Alicia/Jerry(In The Eye)/Michelle/Charley/Ivan/Dennis/Katrina/Rita/Wilma/Humberto/Ike/Harvey
Member: National Weather Association
Facebook.com/Weather Infinity
Twitter @WeatherInfinity
Member: National Weather Association
Facebook.com/Weather Infinity
Twitter @WeatherInfinity
Andrew wrote:This constant wnw movement is pretty concerning. Already a good bit farther south then the models projected
Andrew, those were my thoughts as well.
-
Portastorm
- Posts: 800
- Joined: Wed Feb 03, 2010 3:04 pm
- Location: Southwest Austin/Oak Hill, TX
- Contact:
Indeed. And NHC mentions that very fact in their recently issued discussion.Andrew wrote:This constant wnw movement is pretty concerning. Already a good bit farther south then the models projected
-
srainhoutx
- Site Admin
- Posts: 19622
- Joined: Tue Feb 02, 2010 2:32 pm
- Location: Maggie Valley, NC
- Contact:
TROPICAL STORM ISAAC DISCUSSION NUMBER 23
NWS NATIONAL HURRICANE CENTER MIAMI FL AL092012
500 PM EDT SUN AUG 26 2012
ALTHOUGH SATELLITE AND RADAR IMAGES HAVE SUGGESTED THAT THE TROPICAL
CYCLONE WAS BECOMING A LITTLE BETTER ORGANIZED...AN AIR FORCE
HURRICANE HUNTER AIRCRAFT INVESTIGATING ISAAC THIS AFTERNOON HAVE
FOUND THAT THERE HAS BEEN NO STRENGTHENING OF THE STORM.
FLIGHT-LEVEL AND SFMR-OBSERVED WINDS SUPPORT AN INTENSITY OF 50 KT.
THERE IS STILL A WELL-ESTABLISHED UPPER-LEVEL OUTFLOW PATTERN OVER
THE SYSTEM...AND VERTICAL SHEAR SHOULD REMAIN FAIRLY LIGHT FOR THE
NEXT COUPLE OF DAYS. INTENSIFICATION STILL SEEMS LIKELY AS ISAAC
MOVES OVER THE EASTERN GULF...AND POSSIBLY OVER THE HIGHER HEAT
CONTENT OF THE LOOP CURRENT. THE OFFICIAL INTENSITY FOREAST IS
CLOSE TO THE LATEST LGEM GUIDANCE...AND NOT MUCH DIFFERENT FROM THE
PREVIOUS NHC FORECAST.
ISAAC HAS MOVED A LITTLE TO THE LEFT OF PREVIOUS PROJECTIONS AND
CENTER FIXES YIELD A 6- TO 12-HOUR AVERAGED MOTION OF 295/15. THE
TRACK FORECAST CONTINUES TO BE CHALLENGING. THE DYNAMICAL MODELS
SHOW THE TROPICAL STORM/HURRICANE GRADUALLY TURNING TO THE RIGHT
AND HEADING FOR A BREAK IN THE SUBTROPICAL RIDGE. HOWEVER...THERE
ARE SUBSTANTIAL DIFFERENCES AMONG THE MOST RELIABLE MODELS AS TO
WHERE ISAAC MIGHT CROSS THE NORTHERN GULF COAST. THE U.K. MET.
OFFICE AND ECMWF MODELS ARE ABOUT 300 N MI TO THE EAST OF THE GFS
AT LANDFALL. IT SHOULD BE NOTED THAT NEARLY ALL OF THE GFS ENSMEBLE
MEMBERS ARE EAST OF THE GFS CONTROL TRACK. BECAUSE OF THE WIDE
MODEL SPREAD...THERE CONTINUES TO BE GREATER THAN USUAL TRACK
FORECAST UNCERTAINTY.
THROUGHOUT THE PERIOD...IT IS IMPORTANT NOT TO FOCUS ON THE EXACT
FORECAST TRACK DUE TO FORECAST UNCERTAINTIES AND THE FACT THAT
SIGNIFICANT HAZARDS EXTEND WELL AWAY FROM THE CENTER.
THE OFFICIAL FORECAST TRACK AND WIND RADII NECESSITATE THE ISSUANCE
OF A HURRICANE WARNING FOR THE NORTHERN GULF COAST AT THIS TIME.
FORECAST POSITIONS AND MAX WINDS
INIT 26/2100Z 24.2N 82.3W 50 KT 60 MPH
12H 27/0600Z 25.1N 83.9W 55 KT 65 MPH
24H 27/1800Z 26.3N 85.9W 60 KT 70 MPH
36H 28/0600Z 27.7N 87.6W 70 KT 80 MPH
48H 28/1800Z 28.9N 88.5W 80 KT 90 MPH
72H 29/1800Z 30.7N 89.5W 85 KT 100 MPH...INLAND
96H 30/1800Z 32.5N 90.0W 30 KT 35 MPH...INLAND
120H 31/1800Z 34.5N 90.0W 20 KT 25 MPH...INLAND
$$
FORECASTER PASCH
NWS NATIONAL HURRICANE CENTER MIAMI FL AL092012
500 PM EDT SUN AUG 26 2012
ALTHOUGH SATELLITE AND RADAR IMAGES HAVE SUGGESTED THAT THE TROPICAL
CYCLONE WAS BECOMING A LITTLE BETTER ORGANIZED...AN AIR FORCE
HURRICANE HUNTER AIRCRAFT INVESTIGATING ISAAC THIS AFTERNOON HAVE
FOUND THAT THERE HAS BEEN NO STRENGTHENING OF THE STORM.
FLIGHT-LEVEL AND SFMR-OBSERVED WINDS SUPPORT AN INTENSITY OF 50 KT.
THERE IS STILL A WELL-ESTABLISHED UPPER-LEVEL OUTFLOW PATTERN OVER
THE SYSTEM...AND VERTICAL SHEAR SHOULD REMAIN FAIRLY LIGHT FOR THE
NEXT COUPLE OF DAYS. INTENSIFICATION STILL SEEMS LIKELY AS ISAAC
MOVES OVER THE EASTERN GULF...AND POSSIBLY OVER THE HIGHER HEAT
CONTENT OF THE LOOP CURRENT. THE OFFICIAL INTENSITY FOREAST IS
CLOSE TO THE LATEST LGEM GUIDANCE...AND NOT MUCH DIFFERENT FROM THE
PREVIOUS NHC FORECAST.
ISAAC HAS MOVED A LITTLE TO THE LEFT OF PREVIOUS PROJECTIONS AND
CENTER FIXES YIELD A 6- TO 12-HOUR AVERAGED MOTION OF 295/15. THE
TRACK FORECAST CONTINUES TO BE CHALLENGING. THE DYNAMICAL MODELS
SHOW THE TROPICAL STORM/HURRICANE GRADUALLY TURNING TO THE RIGHT
AND HEADING FOR A BREAK IN THE SUBTROPICAL RIDGE. HOWEVER...THERE
ARE SUBSTANTIAL DIFFERENCES AMONG THE MOST RELIABLE MODELS AS TO
WHERE ISAAC MIGHT CROSS THE NORTHERN GULF COAST. THE U.K. MET.
OFFICE AND ECMWF MODELS ARE ABOUT 300 N MI TO THE EAST OF THE GFS
AT LANDFALL. IT SHOULD BE NOTED THAT NEARLY ALL OF THE GFS ENSMEBLE
MEMBERS ARE EAST OF THE GFS CONTROL TRACK. BECAUSE OF THE WIDE
MODEL SPREAD...THERE CONTINUES TO BE GREATER THAN USUAL TRACK
FORECAST UNCERTAINTY.
THROUGHOUT THE PERIOD...IT IS IMPORTANT NOT TO FOCUS ON THE EXACT
FORECAST TRACK DUE TO FORECAST UNCERTAINTIES AND THE FACT THAT
SIGNIFICANT HAZARDS EXTEND WELL AWAY FROM THE CENTER.
THE OFFICIAL FORECAST TRACK AND WIND RADII NECESSITATE THE ISSUANCE
OF A HURRICANE WARNING FOR THE NORTHERN GULF COAST AT THIS TIME.
FORECAST POSITIONS AND MAX WINDS
INIT 26/2100Z 24.2N 82.3W 50 KT 60 MPH
12H 27/0600Z 25.1N 83.9W 55 KT 65 MPH
24H 27/1800Z 26.3N 85.9W 60 KT 70 MPH
36H 28/0600Z 27.7N 87.6W 70 KT 80 MPH
48H 28/1800Z 28.9N 88.5W 80 KT 90 MPH
72H 29/1800Z 30.7N 89.5W 85 KT 100 MPH...INLAND
96H 30/1800Z 32.5N 90.0W 30 KT 35 MPH...INLAND
120H 31/1800Z 34.5N 90.0W 20 KT 25 MPH...INLAND
$$
FORECASTER PASCH
- Attachments
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Carla/Alicia/Jerry(In The Eye)/Michelle/Charley/Ivan/Dennis/Katrina/Rita/Wilma/Humberto/Ike/Harvey
Member: National Weather Association
Facebook.com/Weather Infinity
Twitter @WeatherInfinity
Member: National Weather Association
Facebook.com/Weather Infinity
Twitter @WeatherInfinity
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biggerbyte
- Posts: 1142
- Joined: Thu Feb 04, 2010 12:15 am
- Location: Porter, Texas. (Montgomery County)
- Contact:
I don't understand why they don't mention the possibilities, and tell folks to be paying attention. Wow!Portastorm wrote:Looks like the folks at HGX are going with the Euro on their forecast and not the GFS ...
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HOUSTON/GALVESTON TX
326 PM CDT SUN AUG 26 2012
.DISCUSSION...
SCATTERED SHRA/TSRA CONTINUE OVER MAINLY THE WESTERN HALF OF
SOUTHEAST TEXAS ALONG A WEAK LOW LEVEL CONVERGENCE ZONE. A WEAK
BOUNDARY WILL APPROACH THE NORTHERN THIRD OF SE TX ON MONDAY AND
PW VALUES INCREASE TO AROUND 2.0 INCHES SO WILL CARRY CHANCE POPS
OVER THE EXTREME NORTH AND SLIGHT CHANCE POPS FURTHER SOUTH. THE
GFS IS MORE AGGRESSIVE THAN THE NAM BUT BOTH MODELS HINT AT PRECIP
OVER THE NORTH. LATEST PROGS DRY THINGS OUT ON TUESDAY WITH PW
VALUES FALLING TO AROUND 1.6 INCHES. THE HIGHER MOISTURE LEVELS
WILL BE OVER THE WESTERN ZONES AND DAYTIME HEATING WILL STILL
TRIGGER ISOLATED SHRA/TSRA DURING THE AFTN. CONVECTIVE TEMPS ON
TUESDAY ARE CONSIDERABLY WARMER...AROUND 92-94 DEGREES.
LONG RANGE MODELS DIFFER RATHER SIGNIFICANTLY ON WEDNESDAY AND
BEYOND. THE CANADIAN...ECMWF AND UKMET ALL TAKE ISAAC TOWARD THE
NORTHERN GULF COAST...AND THEN NORTHWARD AWAY FROM TEXAS. THE GFS
IS AN OUTLIER AND TAKES THE STORM TOWARD LOUISIANA AND THEN SLOWLY
MOVES THE STORM INTO TEXAS. A MID LATITUDE TROUGH CROSSING THE
EASTERN U.S. SHOULD BE STRONG ENOUGH TO PULL THE SYSTEM NORTHWARD.
CURRENT TPC TRACK TAKES THE STORM TOWARD THE MISSISSIPPI COAST.
WILL LEAN HEAVILY TOWARD THE ECMWF SOLUTION MID WEEK AND BEYOND.
THIS MEANS ABOVE NORMAL TEMPERATURES AND RELATIVELY LOW DEW PTS.
IN FACT...THE ECMWF DEW PTS DROP INTO THE LOWER 50S ON THURSDAY.
FEEL A LARGE DIURNAL SPREAD IN TEMPERATURES WILL BE POSSIBLE DUE
TO THE DRY AIR IN PLACE ON THE WEST SIDE OF ISAAC. IF THE GFS IS
CORRECT...THE FORECAST WILL UNDERGO SIGNIFICANT CHANGES WITH
HIGHER RAIN CHANCES ON THURSDAY. AGAIN...AT THIS TIME...THE GFS IS
THE OUTLIER AND HOPEFULLY A CONSENSUS WILL BUILD LATER TONIGHT.
A WEAKNESS ALOFT WILL DEVELOP OVER THE WEEKEND AND MOISTURE LEVELS
BRIEFLY INCREASE. WILL ADD 20 POPS FOR BOTH SAT/SUN. TEMPS WILL
TREND SLIGHTLY COOLER NEXT WEEKEND WITH MORE CLOUD COVER AND LOWER
HEIGHTS.
Last edited by biggerbyte on Sun Aug 26, 2012 4:39 pm, edited 1 time in total.
-
Katdaddy
- Global Moderator
- Posts: 2507
- Joined: Thu Feb 04, 2010 8:18 am
- Location: League City, Tx
- Contact:
The wait and see continues this evening. I have spent most of the day reading and staring at model runs and satellite loops of the GOM and upstream across NA. Things we know for sure this evening....Isaac is in the GOM and a very large system which is becoming better organized in the last few images. The night crew will be very busy.
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Bluefalcon
- Posts: 129
- Joined: Fri Jun 25, 2010 6:14 pm
- Location: Round Rock, TX
- Contact:
Recon Mission #21 is outbound of Isaac, heading for home. Last center fix was 24.00N 82.01W. About 40 miles SSW of Key West, FL. Last recon fix was about 20 miles due West of the previous recon fix. Mission #23 "kermit" P-3 Orion on the on way in.
Put the wet stuff on the red stuff!
Well one saving grace is that it is still a Tropical Storm and is not bombing YET.
I guess it is a wait and see game. Just remember folks what happened during Hurricane Ike.
I guess it is a wait and see game. Just remember folks what happened during Hurricane Ike.
When is the next model run?
No rain, no rainbows.
just wonderingskidog40 wrote:on the water vapor loop, look at circulation by Bay of Campeche. can this cause a different path? just wondering
I still dont get why NHC only moved the track a hair....If ever I was expecting them to make a nice shift, it was this one....and nothing! Well...barely. I thought they moved with model consensus....
Mike
Beaumont, TX
(IH-10 & College Street)
Beaumont, TX
(IH-10 & College Street)
How will the more southern location affect the track of Isaac?Andrew wrote:This constant wnw movement is pretty concerning. Already a good bit farther south then the models projected
I'm thinking you'll see some gradual shifts overnight. I wouldn't be surprised to wake up tomorrow morning with some type of Watches and Warnings issued for your area east into Louisiana. Isaac is a very large storm and going to have far reaching effects.
~~~When Thunder Roars Go Indoors~~~
~~~Turn Around Don't Drown~~~
~~~Run From The Water, Hide From The Wind~~~
~~~Turn Around Don't Drown~~~
~~~Run From The Water, Hide From The Wind~~~
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Andrew
- Site Admin
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- Location: North-West Houston
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skidog40 wrote:just wonderingskidog40 wrote:on the water vapor loop, look at circulation by Bay of Campeche. can this cause a different path? just wondering
That ULL right now and into the future will cause some shear problems but as we continue into the longer range it should actually help the outflow of Isaac and help to filter it. Right now though the main concern is the dry air to the south and the cutoff the Caribbean islands are causing to Isaac's southern side.
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Andrew wrote:skidog40 wrote:just wonderingskidog40 wrote:on the water vapor loop, look at circulation by Bay of Campeche. can this cause a different path? just wondering
That ULL right now and into the future will cause some shear problems but as we continue into the longer range it should actually help the outflow of Isaac and help to filter it. Right now though the main concern is the dry air to the south and the cutoff the Caribbean islands are causing to Isaac's southern side.
Yep ... Isaac has to get away from Cuba before any real intensification can begin.
~~~When Thunder Roars Go Indoors~~~
~~~Turn Around Don't Drown~~~
~~~Run From The Water, Hide From The Wind~~~
~~~Turn Around Don't Drown~~~
~~~Run From The Water, Hide From The Wind~~~
Seeing some changes with the 18z GFS.