Tropical Depression Isaac:

Tropical Weather Discussions and Analysis
User avatar
srainhoutx
Site Admin
Site Admin
Posts: 19612
Joined: Tue Feb 02, 2010 2:32 pm
Location: Maggie Valley, NC
Contact:

Code: Select all

WEATHER RECONNAISSANCE FLIGHTS
CARCAH, NATIONAL HURRICANE CENTER, MIAMI, FL.
1030 AM EDT TUE 21 AUGUST 2012
SUBJECT: TROPICAL CYCLONE PLAN OF THE DAY (TCPOD)
         VALID 22/1100Z TO 23/1100Z AUGUST 2012
         TCPOD NUMBER.....12-094

I.  ATLANTIC REQUIREMENTS 
    1. TROPICAL DEPRESSION NINE
       FLIGHT ONE --TEAL 73--        FLIGHT TWO --NOAA 42--
       A. 22/1800Z, 23/0000Z         A. 23/0000Z
       B. AFXXX 0309A CYCLOME        B. NOAA2 0409A CYCLONE
       C. 22/1600Z                   C. 22/2000Z
       D. 15.7N 60.0W                D. 15.9N 61.5W
       E. 22/1730Z TO 23/0000Z       E. 22/2130 TO 23/0330Z
       F. SFC TO 15,000 FT           F. SFC TO 15,000 FT

       FLIGHT THREE --TEAL 71--      FLIGHT FOUR --NOAA 42--
       A. 23/0600Z, 1200Z            A. 23/1200Z
       B. AFXXX 0509A CYCLONE        B. NOAA2 0609A CYCLONE
       C. 23/0400Z                   C. 23/0800Z
       D. 16.0N 63.0W                D. 16.2N 64.6W
       E. 23/0530Z TO 23/1200Z       E. 23/0900Z TO 23/1430Z
       F. SFC TO 15,000 FT           F. SFC TO 15,000 FT

    2. SUCCEEDING DAY OUTLOOK:
       A. CONTINUE 6-HRLY FIXES. 
       B. A NOAA P-3 MISSION AT 23/2000Z AND 24/0800Z.
       C. A G-IV SYNOPTIC FLOW MISSION AT 23/1730Z.
    3. REMARK: INVEST MISSION IN THE GULF OF MEXICO FOR
       21/1600Z CANCELED BY NHC AT 21/0930Z.
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
User avatar
srainhoutx
Site Admin
Site Admin
Posts: 19612
Joined: Tue Feb 02, 2010 2:32 pm
Location: Maggie Valley, NC
Contact:

The 12Z GFS Ensembles have made a fairly significant shift W into the Gulf. The ensemble mean had been Florida and the Bahamas prior to the 12Z output today...
Attachments
08212012 12Z GFS Ensembles 12zgfsensemble500mbHGHTtropical204.gif
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
User avatar
wxman57
Global Moderator
Global Moderator
Posts: 2621
Joined: Thu Feb 04, 2010 5:34 am
Location: Southwest Houston (Westbury)
Contact:

They're more in line with the operational GFS run now. Just west of the FL Peninsula. Interesting week ahead...
biggerbyte
Posts: 1142
Joined: Thu Feb 04, 2010 12:15 am
Location: Porter, Texas. (Montgomery County)
Contact:

This far out the models are completely useless. The only purpose they serve, at this stage, is to provide most likely landfall, given today's data input, and what "might" happen tomorrow.

Although I suspect landfall to be LA, east, let us not forget what happened with Ike. The models, and many Pro Mets said no way for Texas. Most everyone forecasted it to go inland well east of here. All that did were following the models. Until this system is somewhere around Cuba, I'm not predicting anything.
User avatar
srainhoutx
Site Admin
Site Admin
Posts: 19612
Joined: Tue Feb 02, 2010 2:32 pm
Location: Maggie Valley, NC
Contact:

wxman57 wrote:They're more in line with the operational GFS run now. Just west of the FL Peninsula. Interesting week ahead...

Yes sir. It certainly appears that way. The 12Z Operational Euro has made a shift a bit W as well...
08212012 12Z Euro 12zeurotropical850mbVortSLP168.gif
08212012 12Z Euro 12zeurotropical850mbVortSLP192.gif
08212012 12Z Euro 12zeurotropical850mbVortSLP216.gif
08212012 12Z Euro 12zeurotropical850mbVortSLP240.gif
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
Snowman
Posts: 191
Joined: Sun Jun 27, 2010 11:25 pm
Location: Mountain View, CA
Contact:

I just arrived at Tulane University in New Orleans to start college a couple of days ago. I am kind of concerned about this storm....
User avatar
jasons2k
Posts: 5361
Joined: Thu Feb 04, 2010 12:54 pm
Location: Imperial Oaks
Contact:

Yikes, hopefully this isn't "Isaac's Storm" redux. That's almost a little too creepy.
User avatar
srainhoutx
Site Admin
Site Admin
Posts: 19612
Joined: Tue Feb 02, 2010 2:32 pm
Location: Maggie Valley, NC
Contact:

1004.9 extrap on the second center pass with TS force winds near 40 mph. Perhaps we have enough to upgrade to Isaac.
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
User avatar
desiredwxgd
Posts: 125
Joined: Wed Feb 03, 2010 6:30 pm
Location: TX/LA/Southern New England
Contact:

Once this one takes off he is gonna be a big one....

Steve, check your private message.
Attachments
td9rbtop.jpg
td9rbtop.jpg (72.75 KiB) Viewed 5498 times
JMS
SR. ENSC.
User avatar
srainhoutx
Site Admin
Site Admin
Posts: 19612
Joined: Tue Feb 02, 2010 2:32 pm
Location: Maggie Valley, NC
Contact:

Product: Air Force Vortex Message (URNT12 KNHC)
Transmitted: 21st day of the month at 19:08Z
Aircraft: Air Force Aircraft (Last 3 digits of the tail number are 307)
Tropical Depression: Number 9 (flight in the North Atlantic basin)
Mission Number: 1
Observation Number: 09
A. Time of Center Fix: 21st day of the month at 18:58:40Z
B. Center Fix Coordinates: 15°20'N 53°20'W (15.3333N 53.3333W)
B. Center Fix Location: 448 miles (722 km) to the ENE (70°) from Bridgetown, Barbados.
C. Minimum Height at Standard Level: Not Available
D. Estimated (by SFMR or visually) Maximum Surface Wind: 40kts (~ 46.0mph)
E. Location of the Estimated Maximum Surface Wind: 20 nautical miles (23 statute miles) to the ENE (61°) of center fix
F. Maximum Flight Level Wind Inbound: From 146° at 44kts (From between the SE and SSE at ~ 50.6mph)
G. Location of Maximum Flight Level Wind Inbound: 21 nautical miles (24 statute miles) to the ENE (60°) of center fix
H. Minimum Sea Level Pressure: 1005mb (29.68 inHg) - Extrapolated
I. Maximum Flight Level Temp & Pressure Altitude Outside Eye: 23°C (73°F) at a pressure alt. of 242m (794ft)
J. Maximum Flight Level Temp & Pressure Altitude Inside Eye: 25°C (77°F) at a pressure alt. of 246m (807ft)
K. Dewpoint Temp (collected at same location as temp inside eye): 25°C (77°F)
K. Sea Surface Temp (collected at same location as temp inside eye): Not Available
L. Eye Character: Not Available
M. Eye Shape: Not Available
N. Fix Determined By: Penetration, Radar, Wind, Pressure and Temperature
N. Fix Level: 1,500 feet
O. Navigation Fix Accuracy: 0.02 nautical miles
O. Meteorological Accuracy: 0 nautical miles
Remarks Section - Remarks That Were Decoded...
Maximum Flight Level Wind: 44kts (~ 50.6mph) in the northeast quadrant at 18:51:00Z
Sea Level Pressure Extrapolation From: Below 1,500 feet
Remarks Section - Additional Remarks...
PRELIMINARY, DO NOT RETRANSMIT
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
User avatar
srainhoutx
Site Admin
Site Admin
Posts: 19612
Joined: Tue Feb 02, 2010 2:32 pm
Location: Maggie Valley, NC
Contact:

Product: Air Force Vortex Message (URNT12 KNHC)
Transmitted: 21st day of the month at 19:17Z
Aircraft: Air Force Aircraft (Last 3 digits of the tail number are 307)
Tropical Depression: Number 9 (flight in the North Atlantic basin)
Mission Number: 1
Observation Number: 09
A. Time of Center Fix: 21st day of the month at 18:58:40Z
B. Center Fix Coordinates: 15°20'N 53°20'W (15.3333N 53.3333W) (View map)
B. Center Fix Location: 448 miles (722 km) to the ENE (70°) from Bridgetown, Barbados.
C. Minimum Height at Standard Level: Not Available
D. Estimated (by SFMR or visually) Maximum Surface Wind: 40kts (~ 46.0mph)
E. Location of the Estimated Maximum Surface Wind: 20 nautical miles (23 statute miles) to the ENE (61°) of center fix
F. Maximum Flight Level Wind Inbound: From 146° at 44kts (From between the SE and SSE at ~ 50.6mph)
G. Location of Maximum Flight Level Wind Inbound: 21 nautical miles (24 statute miles) to the ENE (60°) of center fix
H. Minimum Sea Level Pressure: 1005mb (29.68 inHg) - Extrapolated
I. Maximum Flight Level Temp & Pressure Altitude Outside Eye: 24°C (75°F) at a pressure alt. of 304m (997ft)
J. Maximum Flight Level Temp & Pressure Altitude Inside Eye: 25°C (77°F) at a pressure alt. of 246m (807ft)
K. Dewpoint Temp (collected at same location as temp inside eye): 25°C (77°F)
K. Sea Surface Temp (collected at same location as temp inside eye): Not Available
L. Eye Character: Not Available
M. Eye Shape: Not Available
N. Fix Determined By: Penetration, Radar, Wind and Pressure
N. Fix Level: 1,500 feet
O. Navigation Fix Accuracy: 0.02 nautical miles
O. Meteorological Accuracy: 2.5 nautical miles
Remarks Section - Remarks That Were Decoded...
Maximum Flight Level Wind: 44kts (~ 50.6mph) in the northeast quadrant at 18:51:00Z
Sea Level Pressure Extrapolation From: Below 1,500 feet
Remarks Section - Additional Remarks...
SPIRAL BAND
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
User avatar
srainhoutx
Site Admin
Site Admin
Posts: 19612
Joined: Tue Feb 02, 2010 2:32 pm
Location: Maggie Valley, NC
Contact:

TROPICAL STORM ISAAC FORECAST/ADVISORY NUMBER 3
NWS NATIONAL HURRICANE CENTER MIAMI FL AL092012
2100 UTC TUE AUG 21 2012

CHANGES IN WATCHES AND WARNINGS WITH THIS ADVISORY...

NONE.

SUMMARY OF WATCHES AND WARNINGS IN EFFECT...

A TROPICAL STORM WARNING IS IN EFFECT FOR...
* MARTINIQUE
* DOMINICA
* GUADELOUPE AND THE SURROUNDING ISLANDS...AND ST. MARTIN
* ST. KITTS...NEVIS...ANTIGUA...MONTSERRAT...ANGUILLA...AND BARBUDA
* SABA...ST. EUSTATIUS...AND ST. MAARTEN

A TROPICAL STORM WATCH IS IN EFFECT FOR...
* BRITISH VIRGIN ISLANDS
* PUERTO RICO...VIEQUES...CULEBRA...AND THE U.S. VIRGIN ISLANDS

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 ELSEWHERE IN HISPANIOLA AND CUBA SHOULD MONITOR THE
PROGRESS OF ISAAC.

TROPICAL STORM CENTER LOCATED NEAR 15.4N 53.9W AT 21/2100Z
POSITION ACCURATE WITHIN 20 NM

PRESENT MOVEMENT TOWARD THE WEST OR 275 DEGREES AT 15 KT

ESTIMATED MINIMUM CENTRAL PRESSURE 1006 MB
MAX SUSTAINED WINDS 35 KT WITH GUSTS TO 45 KT.
34 KT....... 40NE 0SE 0SW 0NW.
12 FT SEAS.. 40NE 0SE 0SW 0NW.
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 15.4N 53.9W AT 21/2100Z
AT 21/1800Z CENTER WAS LOCATED NEAR 15.3N 53.2W

FORECAST VALID 22/0600Z 15.6N 56.4W
MAX WIND 40 KT...GUSTS 50 KT.
34 KT... 50NE 30SE 20SW 50NW.

FORECAST VALID 22/1800Z 15.9N 59.8W
MAX WIND 45 KT...GUSTS 55 KT.
34 KT... 60NE 30SE 30SW 60NW.

FORECAST VALID 23/0600Z 16.3N 63.1W
MAX WIND 50 KT...GUSTS 60 KT.
50 KT... 20NE 0SE 0SW 20NW.
34 KT... 70NE 40SE 30SW 70NW.

FORECAST VALID 23/1800Z 16.6N 66.3W
MAX WIND 65 KT...GUSTS 80 KT.
50 KT... 40NE 30SE 20SW 40NW.
34 KT... 90NE 60SE 40SW 90NW.

FORECAST VALID 24/1800Z 17.0N 71.0W
MAX WIND 75 KT...GUSTS 90 KT.
50 KT... 50NE 30SE 20SW 50NW.
34 KT...110NE 70SE 50SW 110NW.

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 25/1800Z 19.5N 75.0W
MAX WIND 75 KT...GUSTS 90 KT.

OUTLOOK VALID 26/1800Z 21.5N 78.0W...INLAND
MAX WIND 65 KT...GUSTS 80 KT.

REQUEST FOR 3 HOURLY SHIP REPORTS WITHIN 300 MILES OF 15.4N 53.9W

NEXT ADVISORY AT 22/0300Z

$$
FORECASTER BEVEN
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
User avatar
srainhoutx
Site Admin
Site Admin
Posts: 19612
Joined: Tue Feb 02, 2010 2:32 pm
Location: Maggie Valley, NC
Contact:

BULLETIN
TROPICAL STORM ISAAC ADVISORY NUMBER 3
NWS NATIONAL HURRICANE CENTER MIAMI FL AL092012
500 PM AST TUE AUG 21 2012

...AIR FORCE RESERVE HURRICANE HUNTER AIRCRAFT FINDS THAT THE
DEPRESSION HAS BECOME A TROPICAL STORM...


SUMMARY OF 500 PM AST...2100 UTC...INFORMATION
----------------------------------------------
LOCATION...15.4N 53.9W
ABOUT 500 MI...810 KM E OF GUADELOUPE
MAXIMUM SUSTAINED WINDS...40 MPH...65 KM/H
PRESENT MOVEMENT...W OR 275 DEGREES AT 17 MPH...28 KM/H
MINIMUM CENTRAL PRESSURE...1006 MB...29.71 INCHES


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

NONE.

SUMMARY OF WATCHES AND WARNINGS IN EFFECT...

A TROPICAL STORM WARNING IS IN EFFECT FOR...
* MARTINIQUE
* DOMINICA
* GUADELOUPE AND THE SURROUNDING ISLANDS...AND ST. MARTIN
* ST. KITTS...NEVIS...ANTIGUA...MONTSERRAT...ANGUILLA...AND BARBUDA
* SABA...ST. EUSTATIUS...AND ST. MAARTEN

A TROPICAL STORM WATCH IS IN EFFECT FOR...
* BRITISH VIRGIN ISLANDS
* PUERTO RICO...VIEQUES...CULEBRA...AND THE U.S. VIRGIN ISLANDS

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 ELSEWHERE IN HISPANIOLA AND CUBA SHOULD MONITOR THE
PROGRESS OF ISAAC.

FOR STORM INFORMATION SPECIFIC TO YOUR AREA IN THE UNITED
STATES...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 500 PM AST...2100 UTC...THE CENTER OF TROPICAL STORM ISAAC WAS
LOCATED NEAR LATITUDE 15.4 NORTH...LONGITUDE 53.9 WEST. ISAAC IS
MOVING TOWARD THE WEST NEAR 17 MPH...28 KM/H...AND THIS GENERAL
MOTION IS EXPECTED TO CONTINUE FOR THE NEXT COUPLE OF DAYS. ON THE
FORECAST TRACK...THE CENTER OF ISAAC SHOULD MOVE THROUGH THE
CENTRAL LESSER ANTILLES WEDNESDAY EVENING...AND EMERGE OVER THE
EASTERN CARIBBEAN SEA BY THURSDAY MORNING.

REPORTS FROM AN AIR FORCE RESERVE HURRICANE HUNTER AIRCRAFT INDICATE
THAT MAXIMUM SUSTAINED WINDS ARE NEAR 40 MPH...65 KM/H...WITH
HIGHER GUSTS. ADDITIONAL STRENGTHENING IS FORECAST DURING THE NEXT
48 HOURS.

TROPICAL STORM FORCE WINDS EXTEND OUTWARD UP TO 45 MILES...75 KM
TO THE NORTHEAST OF THE CENTER.

THE MINIMUM CENTRAL PRESSURE JUST MEASURED BY THE HURRICANE HUNTER
AIRCRAFT IS 1006 MB...29.71 INCHES.


HAZARDS AFFECTING LAND
----------------------
WIND...TROPICAL STORM CONDITIONS ARE EXPECTED TO REACH THE WARNING
AREA BY WEDNESDAY AFTERNOON...MAKING OUTSIDE PREPARATIONS DIFFICULT
OR DANGEROUS.

RAINFALL...TOTAL RAIN ACCUMULATIONS OF 4 TO 8 INCHES ARE POSSIBLE
OVER THE NORTHERN WINDWARD ISLANDS AND THE LEEWARD ISLANDS. TOTAL
RAIN ACCUMULATIONS OF 1 TO 3 INCHES WITH MAXIMUM AMOUNTS OF 6
INCHES ARE POSSIBLE OVER PUERTO RICO AND THE VIRGIN ISLANDS.

STORM SURGE...A STORM SURGE WILL RAISE WATER LEVELS BY AS MUCH AS 1
TO 3 FEET ABOVE NORMAL TIDE LEVELS IN THE NORTHERN LEEWARD ISLANDS.
NEAR THE COAST...THE SURGE WILL BE ACCOMPANIED BY DANGEROUS WAVES.

SURF...DANGEROUS SURF AND RIP CURRENT CONDITIONS WILL AFFECT THE
WINDWARD AND LEEWARD ISLANDS DURING THE NEXT COUPLE OF DAYS. PLEASE
CONSULT PRODUCTS FROM YOUR LOCAL WEATHER OFFICE FOR MORE
INFORMATION.


NEXT ADVISORY
-------------
NEXT INTERMEDIATE ADVISORY...800 PM AST.
NEXT COMPLETE ADVISORY...1100 PM AST.

$$
FORECASTER BEVEN
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
User avatar
srainhoutx
Site Admin
Site Admin
Posts: 19612
Joined: Tue Feb 02, 2010 2:32 pm
Location: Maggie Valley, NC
Contact:

TROPICAL STORM ISAAC DISCUSSION NUMBER 3
NWS NATIONAL HURRICANE CENTER MIAMI FL AL092012
500 PM AST TUE AUG 21 2012

AN AIR FORCE RESERVE HURRICANE HUNTER AIRCRAFT INVESTIGATING THE
DEPRESSION REPORTED 44-KT FLIGHT-LEVEL WINDS AT 1000 FT TO THE
NORTHEAST OF THE CENTER...AS WELL AS BIAS-CORRECTED SFMR SURFACE
WINDS ESTIMATES OF 35 KT. THE MINIMUM CENTRAL PRESSURE WAS NEAR
1005 MB. BASED ON THESE DATA...THE DEPRESSION IS UPGRADED TO
TROPICAL STORM ISAAC. DESPITE THE UPGRADE...THE CYCLONE REMAINS
SOMEWHAT DISORGANIZED...WITH THE LOW-LEVEL CENTER PARTLY EXPOSED TO
THE NORTH OF THE MAIN CONVECTIVE MASS.

THE LOW-LEVEL CENTER HAS NUDGED NORTHWARD DURING THE AFTERNOON...BUT
THE LONGER TERM MOTION IS 275/15. ISAAC REMAINS SOUTH OF A
DEEP-LAYER SUBTROPICAL RIDGE THAT IS FORECAST TO REMAIN INTACT
FOR THE NEXT 72 HR...WHICH SHOULD KEEP THE CYCLONE MOVING GENERALLY
WESTWARD AS SHOWN BY THE TIGHTLY CLUSTERED TRACK MODEL GUIDANCE.
AFTER THAT...THE GLOBAL MODELS CONTINUE TO FORECAST A SHORTWAVE
TROUGH TO DIG SOUTHWARD OVER THE SOUTHEASTERN U.S. AND THE GULF OF
MEXICO...WHICH IS EXPECTED TO WEAKEN THE RIDGE ACROSS FLORIDA AND
THE BAHAMAS. THIS SHOULD ALLOW THE CYCLONE TO TURN WEST-
NORTHWESTWARD AND SLOW DOWN OVER THE NORTH-CENTRAL CARIBBEAN SEA AND
THE GREATER ANTILLES. THE GUIDANCE HAS BECOME LESS CONSISTENT
SINCE THE PREVIOUS ADVISORY. WHILE THE CENTER OF THE GUIDANCE
ENVELOPE HAS CHANGED LITTLE...THE ECMWF HAS SHIFTED WELL TO THE
LEFT OF ITS PREVIOUS FORECAST AND NOW CALLS FOR A WESTWARD MOTION
AFTER ISAAC PASSES HISPANIOLA. THE GFS ENSEMBLES HAVE ALSO SHIFTED
WESTWARD...ALTHOUGH THE ENSEMBLE MEAN STILL LIES NEAR THE FORECAST
TRACK. THE NEW TRACK IS NUDGED A LITTLE TO THE NORTH OF THE
PREVIOUS TRACK BEFORE 72 HR...AND THEN IS NUDGED A LITTLE TO THE
RIGHT THEREAFTER. THE TRACK FORECAST AFTER 72 HR LIES NEAR THE
LEFT EDGE OF THE GUIDANCE ENVELOPE...WITH ONLY THE ECMWF WELL TO
THE LEFT OF THE CURRENT FORECAST. USERS ARE CAUTIONED THAT FIVE-DAY
TRACK ERRORS AVERAGE ABOUT 225 N MI.

ISAAC CONTINUES TO EXPERIENCE SOME LIGHT NORTHEASTERLY VERTICAL WIND
SHEAR...AND IT MAY NOT YET HAVE FULLY MIXED OUT THE DRY AIR THAT
HAS BEEN AFFECTING IT. THE SHEAR IS FORECAST TO DIMINISH IN 12-24
HR...WHICH SHOULD ALLOW SOME STRENGTHENING. THAT BEING SAID...THE
GFDL AND HWRF MODELS HAVE BACKED OFF ON THEIR FORECASTS OF
INTENSIFICATION...AND THE SHIPS AND LGEM MODELS ARE ALSO LESS
BULLISH. BASED ON THIS...THE NEW INTENSITY FORECAST SHOWS A LITTLE
LESS STRENGTHENING THAN THE PREVIOUS ADVISORY. THE INTENSITY
FORECAST AFTER 72 HR HAS AGAIN BEEN REDUCED DUE TO THE FORECAST
TRACK SHOWING INCREASED LAND INTERACTION WITH HISPANIOLA AND CUBA.




FORECAST POSITIONS AND MAX WINDS

INIT 21/2100Z 15.4N 53.9W 35 KT 40 MPH
12H 22/0600Z 15.6N 56.4W 40 KT 45 MPH
24H 22/1800Z 15.9N 59.8W 45 KT 50 MPH
36H 23/0600Z 16.3N 63.1W 50 KT 60 MPH
48H 23/1800Z 16.6N 66.3W 65 KT 75 MPH
72H 24/1800Z 17.0N 71.0W 75 KT 85 MPH
96H 25/1800Z 19.5N 75.0W 75 KT 85 MPH
120H 26/1800Z 21.5N 78.0W 65 KT 75 MPH...INLAND

$$
FORECASTER BEVEN
Attachments
08212012 5 PM EDT Isaac 205537W5_NL_sm.gif
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
unome
Posts: 3059
Joined: Fri Feb 12, 2010 6:11 pm

I've been waiting for this update from http://hurricanecity.com/

http://youtu.be/KC_VCRMxgI4
Texas Pirate

TROPICAL STORM ISAAC ADVISORY NUMBER 4
NWS NATIONAL HURRICANE CENTER MIAMI FL AL092012
1100 PM AST TUE AUG 21 2012

...ISAAC CONTINUES WESTWARD TOWARD THE LEEWARD ISLANDS...TROPICAL
STORM WARNINGS ISSUED FOR PUERTO RICO AND THE VIRGIN ISLANDS...


SUMMARY OF 1100 PM AST...0300 UTC...INFORMATION
-----------------------------------------------
LOCATION...15.6N 55.6W
ABOUT 390 MI...625 KM E OF GUADELOUPE
MAXIMUM SUSTAINED WINDS...40 MPH...65 KM/H
PRESENT MOVEMENT...W OR 275 DEGREES AT 18 MPH...30 KM/H
MINIMUM CENTRAL PRESSURE...1006 MB...29.71 INCHES


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

THE GOVERNMENT OF ANTIGUA AND BARBUDA HAS CHANGED THE TROPICAL STORM
WATCH FOR THE BRITISH VIRGIN ISLANDS TO A TROPICAL STORM WARNING.

THE TROPICAL STORM WATCH FOR PUERTO RICO...VIEQUES...CULEBRA...AND
THE U.S. VIRGIN ISLANDS HAS BEEN CHANGED TO A TROPICAL STORM
WARNING.

A HURRICANE WATCH HAS BEEN ISSUED FOR PUERTO RICO...VIEQUES...
CULEBRA...AND THE U.S. VIRGIN ISLANDS.

SUMMARY OF WATCHES AND WARNINGS IN EFFECT...

A TROPICAL STORM WARNING IS IN EFFECT FOR...
* MARTINIQUE
* DOMINICA
* GUADELOUPE AND THE SURROUNDING ISLANDS...AND ST. MARTIN
* ST. KITTS...NEVIS...ANTIGUA...BARBUDA...MONTSERRAT...AND ANGUILLA
* SABA...ST. EUSTATIUS...AND ST. MAARTEN
* BRITISH VIRGIN ISLANDS
* PUERTO RICO...VIEQUES...CULEBRA...AND THE U.S. VIRGIN ISLANDS

A HURRICANE WATCH IS IN EFFECT FOR...
* PUERTO RICO...VIEQUES...CULEBRA...AND THE U.S. VIRGIN ISLANDS

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.

INTERESTS IN HISPANIOLA AND CUBA 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 15.6 NORTH...LONGITUDE 55.6 WEST. ISAAC IS
MOVING TOWARD THE WEST NEAR 18 MPH...30 KM/H...AND THIS GENERAL
MOTION IS EXPECTED TO CONTINUE FOR THE NEXT COUPLE OF DAYS. ON THE
FORECAST TRACK...THE CENTER OF ISAAC SHOULD MOVE THROUGH THE
LEEWARD ISLANDS WEDNESDAY EVENING...AND MOVE OVER THE NORTHEASTERN
CARIBBEAN SEA ON THURSDAY.

MAXIMUM SUSTAINED WINDS ARE NEAR 40 MPH...65 KM/H...WITH HIGHER
GUSTS. STRENGTHENING IS FORECAST DURING THE NEXT 48 HOURS
User avatar
Katdaddy
Global Moderator
Global Moderator
Posts: 2501
Joined: Thu Feb 04, 2010 8:18 am
Location: League City, Tx
Contact:

Many days to watch Isaac. By this weekend we will have a good idea if he is Gulf-bound or FLA-bound.
Andrew
Site Admin
Site Admin
Posts: 3438
Joined: Wed Feb 03, 2010 9:46 pm
Location: North-West Houston
Contact:

00z Euro is concerning for the gulf coast. To me it looks more realistic with ridging developing over the east coast before another trough makes its way across the U.S. The gfs shows mid level ridging develop somewhat in the longer range also but has Issac finding the weakness. Everyone needs to keep an eye on this one because no matter where it hits models are indicating a strong storm possibly affecting the continental U.S.
For Your Infinite Source For All Things Weather Visit Our Facebook
User avatar
srainhoutx
Site Admin
Site Admin
Posts: 19612
Joined: Tue Feb 02, 2010 2:32 pm
Location: Maggie Valley, NC
Contact:

TROPICAL STORM ISAAC DISCUSSION NUMBER 5
NWS NATIONAL HURRICANE CENTER MIAMI FL AL092012
500 AM AST WED AUG 22 2012

SATELLITE IMAGERY INDICATES A LARGE CENTRAL DENSE OVERCAST FEATURE
HAS DEVELOPED OVER THE LOW-LEVEL CENTER...WHICH INCLUDES SOME COLD
CLOUD TOPS OF -82 TO -86C VERY NEAR THE CENTER. HOWEVER...THE SHARP
INCREASE IN INNER-CORE CONVECTION HAS NOT YET TRANSLATED INTO ANY
SIGNIFICANT INTENSIFICATION. AN AIR FORCE RESERVE RECONNAISSANCE
AIRCRAFT INVESTIGATING ISAAC THIS MORNING HAS ONLY FOUND THE
CENTRAL PRESSURE TO BE 1003 MB AND 850 MB FLIGHT-LEVEL WINDS OF 47
KT...WHICH EQUATES TO ABOUT A 40-KT INTENSITY ESTIMATE. SFMR WINDS
IN VERY HEAVY RAIN HAVE BEEN AS HIGH AS 61 KT. THE BIAS-ADJUSTED
SFMR WINDS HAVE BEEN RUNNING AS HIGH AS 54 KT...BUT EVEN THOSE
VALUES APPEAR TO BE INFLATED. UNTIL THE AIRCRAFT COMPLETES ITS
MISSION... THE INITIAL INTENSITY WILL REMAIN AT 40 KT BASED ON THE
1003 MB PRESSURE-WIND RELATIONSHIP.

THE INITIAL MOTION ESTIMATE IS 270/15 KT. THE INITIAL POSITION IS A
BLEND OF THE RECON FIXES AND SATELLITE POSITIONS...AND CONTINUITY
WITH PREVIOUS FORECAST TRACK. THERE IS NO SIGNIFICANT CHANGE TO THE
PREVIOUS FORECAST TRACK OR REASONING. THE EAST-WEST ORIENTED
SUBTROPICAL RIDGE TO THE NORTH OF ISAAC ALONG 30N LATITUDE IS
FORECAST BY ALL OF THE GLOBAL MODELS TO REMAIN INTACT ACROSS
FLORIDA AND THE SOUTHEASTERN U.S. THROUGH 72 HOURS OR SO. AFTER
THAT...A BROAD MID- TO UPPER-LEVEL TROUGH CURRENTLY LOCATED OVER
THE CENTRAL U.S. FROM THE GREAT LAKES SOUTHWARD TO THE CENTRAL GULF
COAST IS EXPECTED TO DIG SOUTHWARD OVER THE NEXT 24 HOURS BEFORE
MOVING EASTWARD. THIS SHOULD RESULT IN AN EROSION OF THE RIDGE
ACROSS THE EASTERN GULF OF MEXICO AND THE SOUTHEASTERN U.S.
INCLUDING FLORIDA AND THE NORTHWESTERN BAHAMAS. THIS DEVELOPING
WEAKNESS IN THE RIDGE SHOULD ALLOW ISAAC TO TURN NORTHWESTWARD
ACROSS EASTERN AND CENTRAL CUBA BY DAYS 4 AND 5. THE NHC MODEL
GUIDANCE IS IN EXCELLENT AGREEMENT ON THIS EVOLVING SCENARIO WITH
THE ECMWF BEING THE LEFTMOST OF THE MODELS...AND THE GFDL AND HWRF
BEING THE RIGHTMOST OF THE MODELS. GIVEN THE RUN-TO-RUN CONSISTENCY
OF THE GFS AND UKMET MODELS...MORE WEIGHT HAS BEEN PLACED ON THOSE
SOLUTIONS...ESPECIALLY SINCE THEY HAVE A STRONGER AND VERTICALLY
DEEPER CYCLONE DEPICTED IN THE MODELS.

SHEAR ANALYSES FROM THE GFS-BASED SHIPS INTENSITY MODEL AND UW-CIMSS
INDICATE BOTH THE DEEP-LAYER AND MID-LEVEL SHEAR VALUES HAVE
DROPPED BELOW 10 KT...WHICH HAS FINALLY ALLOWED DEEP CONVECTION TO
DEVELOP AND PERSIST OVER THE LOW-LEVEL CENTER. THE SHEAR IS
FORECAST TO GRADUALLY DECREASE TO VALUES BELOW 5 KT BY 24 HOURS...
WHICH SHOULD ALLOW ISAAC TO STRENGTHEN TO A HURRICANE BY 48 HOURS.
AT 72 AND 96 HOURS...THE INTENSITY HAS BEEN DECREASED DUE TO
EXPECTED LAND INTERACTION WITH HAITI AND EASTERN CUBA. AFTER 96
HOURS...HOWEVER...ISAAC SHOULD BE MOVING BACK OVER THE VERY WARM
WATER BETWEEN CUBA AND FLORIDA. WITH SEA-SURFACE TEMPERATURES
EXPECTED TO BE NEAR 30C AND THE GFS AND UKMET MODELS DEPICTING A
EXTENSIVE UPPER-LEVEL OUTFLOW REGIME COMPLETE WITH DUAL OUTFLOW
CHANNELS TO THE NORTHWEST AND SOUTHEAST...STRENGTHENING APPEARS
LIKELY. THE OFFICIAL INTENSITY REMAINS ON THE CONSERVATIVE SIDE DUE
TO UNCERTAINTY IN HOW LONG AND HOW MUCH ISAAC WILL INTERACT WITH
HISPANIOLA AND CUBA...AND IS CLOSE TO A BLEND OF THE SHIPS...
DECAY-SHIPS...AND LGEM STATISTICAL-DYNAMICAL INTENSITY MODELS.

FORECAST POSITIONS AND MAX WINDS

INIT 22/0900Z 15.5N 57.3W 40 KT 45 MPH
12H 22/1800Z 15.9N 59.7W 45 KT 50 MPH
24H 23/0600Z 16.3N 62.8W 55 KT 65 MPH
36H 23/1800Z 16.8N 65.7W 65 KT 75 MPH
48H 24/0600Z 17.3N 68.4W 75 KT 85 MPH
72H 25/0600Z 18.8N 73.2W 65 KT 75 MPH...OVER WATER
96H 26/0600Z 21.8N 77.1W 65 KT 75 MPH...OVER WATER
120H 27/0600Z 24.8N 80.0W 80 KT 90 MPH

$$
FORECASTER STEWART
Attachments
08222012 5 AM EDT Isaac 085616W5_NL_sm.gif
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
biggerbyte
Posts: 1142
Joined: Thu Feb 04, 2010 12:15 am
Location: Porter, Texas. (Montgomery County)
Contact:

Agreed! Remember, it was the loan wolf, the Euro that showed Ike coming to Texas. While I don't put much into such things, one can not ignore when we see such persistence and accuracy. We are in a highly uncertain stage with this system. Everyone from Texas to the Carolinas should pay attention. We should be able to safely narrow that down come Thursday or Friday. As of now, The NHC is not giving much, if any credence to the Euro. They have this system encompassing Florida. We will see about that. The players are the Ridge, the weakness, and the strength of Isaac as he enters the NW Carribean.


Stay Tuned.
Post Reply
  • Information
  • Who is online

    Users browsing this forum: No registered users and 30 guests