[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 252356
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
805 PM EDT THU AUG 25 2011

TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL
AMERICA...GULF OF MEXICO...CARIBBEAN SEA...NORTHERN SECTIONS OF
SOUTH AMERICA...AND ATLANTIC OCEAN TO THE AFRICAN COAST FROM THE
EQUATOR TO 32N. THE FOLLOWING INFORMATION IS BASED ON SATELLITE
IMAGERY...WEATHER OBSERVATIONS...RADAR...AND METEOROLOGICAL
ANALYSIS.

BASED ON 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
2315 UTC.

...SPECIAL FEATURE...
HURRICANE IRENE IS CENTERED NEAR 27.7N 77.4W AT 26/0000 UTC OR
ABOUT 460 NM SSW OF CAPE HATTERAS NORTH CAROLINA MOVING NNW AT
12 KT. ESTIMATED MINIMUM CENTRAL PRESSURE IS 946 MB. MAXIMUM
SUSTAINED WIND SPEED IS 100 KT WITH GUSTS TO 120 KT. PLEASE SEE
THE LATEST INTERMEDIATE PUBLIC ADVISORY UNDER AWIPS/WMO HEADER
MIATCPAT4/WTNT34 KNHC AND THE FULL FORECAST/ADVISORY UNDER
AWIPS/WMO HEADER MIATCMAT4/WTNT24 KNHC FOR MORE DETAILS.
NUMEROUS STRONG CONVECTION IS WITHIN 75 NM OF THE CENTER.
NUMEROUS MODERATE/SCATTERED STRONG CONVECTION EXTENDS WITHIN 120
NM. SCATTERED MODERATE CONVECTION IS WITHIN 200 NM FROM THE
CENTER ALONG THE WRN SEMI-CIRCLE...AND WITHIN 300 NM ALONG THE
ERN SEMI-CIRCLE. NUMEROUS MODERATE/ISOLATED STRONG CONVECTION IS
ALSO FARTHER NE OF THE CENTER FROM 28N-32N BETWEEN 70W-79W. SOME
OF THIS HEAVY RAINFALL CONTINUES TO IMPACT THE NW BAHAMAS. OUTER
RAINBANDS HAVE ALSO ALREADY BEEN IMPACTING MUCH OF THE ERN COAST
OF FLORIDA...AND WILL SOON BE REACHING THE SOUTH CAROLINA AND
NORTH CAROLINA COASTS.

TROPICAL DEPRESSION TEN IS CENTERED SW OF THE CAPE VERDE ISLANDS
NEAR 13.8N 32.4W AT 25/2100 UTC MOVING WNW AT 8 KT. ESTIMATED
MINIMUM CENTRAL PRESSURE IS 1009 MB. MAXIMUM SUSTAINED WIND
SPEED IS 30 KT WITH GUSTS TO 40 KT. PLEASE SEE THE LATEST
FORECAST/ADVISORY UNDER AWIPS/WMO HEADER MIATCMAT5/WTNT25 KNHC
FOR MORE DETAILS. NUMEROUS STRONG CONVECTION IS W OF THE CENTER
FROM 12N-15N BETWEEN 33W-36W. T.D. TEN IS FORECAST TO BECOME A
TROPICAL STORM BY THIS TIME TOMORROW.

...THE ITCZ/THE MONSOON TROUGH...

THE MONSOON TROUGH IS ANALYZED ACROSS AFRICA BARELY EXTENDING
OFF THE COAST TO 19N19W. THE ITCZ PICKS UP ON THE OTHER SIDE OF
T.D. TEN ALONG 9N41W TO 9N62W. SCATTERED MODERATE/ISOLATED
STRONG CONVECTION IS OFF THE W AFRICAN COAST FROM 10N-13N
BETWEEN 14W-19W. SIMILAR ACTIVITY IS S OF THE ITCZ AXIS FROM
6N-8N BETWEEN 47W-56W.

...DISCUSSION...

GULF OF MEXICO...
A WEAK PRESSURE GRADIENT IS ACROSS MUCH OF THE WRN GULF OF
MEXICO SUPPORTING LIGHT ELY SURFACE WINDS ACROSS THE NW AREA AND
VERY WEAK CYCLONIC FLOW IN THE FAR SW GULF.. CYCLONIC FLOW HAS
BEGUN OVER THE FAR ERN GULF AROUND THE CIRCULATION OF HURRICANE
IRENE IN THE W ATLC. SURFACE OBSERVATIONS INDICATE WINDS UP TO
20 KTS NEAR THE FLORIDA KEYS. SOME OF THE EXTREME OUTER
RAINBANDS HAVE BEEN IMPACTING THE FLORIDA PENINSULA DURING THE
DAY...SOME REACHING THE WRN COAST AND IMMEDIATE OFFSHORE WATERS.
ISOLATED SHOWERS/THUNDERSTORMS ALSO DOT THE FAR WRN GULF W OF
90W ASSOCIATED WITH AN AREA OF AREA OF DEEP LAYER MOISTURE
EVIDENT IN TOTAL PRECIPITABLE WATER IMAGERY. ALOFT...A DRY UPPER
LEVEL TROUGH COVERS THE ERN GULF CENTERED NEAR 26N86W. A
SHORTWAVE UPPER TROUGH IS ALSO OVER THE FAR NW GULF FROM SRN
LOUISIANA TO NEAR 28N96W...WHICH MAY BE SUPPORTING SOME OF THE
SHOWER ACTIVITY IN THIS AREA. EXPECT RAINY AND WINDY CONDITIONS
TO REMAIN ACROSS THE FLORIDA PENINSULA AS HURRICANE IRENE MOVES
NNW.

CARIBBEAN SEA...
A FEW ISOLATED SHOWERS ARE OVER CUBA ASSOCIATED WITH HURRICANE
IRENE IN THE W ATLC. W-SW FLOW COVERS THE NW CARIBBEAN AROUND
THE CIRCULATION OF IRENE. TOTAL PRECIPITABLE WATER IMAGERY
INDICATES ENHANCED MOISTURE ACROSS THE CENTRAL AND ERN CARIBBEAN
BEING SUCKED NWD AROUND IRENE. THIS IS SUPPORTING OVERCAST SKIES
AND ISOLATED SHOWERS FROM THE SW CARIBBEAN TO HISPANIOLA.
SCATTERED SHOWERS/THUNDERSTORMS ARE ALSO MOVING ACROSS THE SRN
WINDWARD ISLANDS. ALOFT...NLY FLOW COVERS THE FAR ERN CARIBBEAN
TURNING MORE ELY ACROSS THE CENTRAL BECOMING SE...AND FINALLY
SWLY ACROSS THE FAR NW CARIBBEAN. EXPECT ENHANCED MOISTURE
VALUES TO REMAIN ACROSS THE CENTRAL CARIBBEAN MOVING INTO THE
WRN CARIBBEAN WITH POSSIBLE ASSOCIATED SHOWER ACTIVITY.

ATLANTIC OCEAN...
HURRICANE IRENE REMAINS THE MAIN FOCUS FOR THE W ATLC. SEE
SPECIAL FEATURES ABOVE FOR MORE DETAILS. OUTFLOW FROM IRENE
DOMINATES THE FAR WRN ATLC ALOFT. TO THE STORMS EAST...AN UPPER
LEVEL TROUGH IS ALONG 57W SUPPORTING SCATTERED
SHOWERS/THUNDERSTORMS FROM 25N-30N BETWEEN 49W-57W. A SURFACE
TROUGH EXTENDS ALONG 25N51W TO 22N47W SUPPORTING ISOLATED
SHOWERS/THUNDERSTORMS FROM 24N-26N BETWEEN 47W-52W. AN UPPER
LEVEL RIDGE IS FARTHER E CENTERED NEAR 20N41W TO THE NW OF T.D.
TEN IN THE TROPICAL ATLC. SURFACE RIDGING DOMINATES THE
REMAINDER OF THE ERN ATLC CENTERED AROUND A PAIR OF 1026 MB
HIGHS NEAR 35N41W AND 35N48W PROVIDING MOSTLY FAIR WEATHER. AN
UPPER LEVEL TROUGH COVERS THE FAR ERN ATLC WITH AXIS FROM THE
AZORES ISLANDS TO NEAR 21N21N. INTERESTS IN THE ERN U.S. COAST
SHOULD MONITOR HURRICANE IRENE AS IT MOVES NNW. T.D. TEN IS
EXPECTED TO MOVE WNW WITH NO IMPACT TO LAND.

ADDITIONAL INFORMATION PLEASE VISIT
HTTP://WWW.HURRICANES.GOV/MARINE

$$
WALTON





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