[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 260622 AAA
TWDAT

TROPICAL WEATHER DISCUSSION...UPDATE
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
205 AM EDT TUE AUG 26 2008

...UPDATE FOR GUSTAV...

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...METEOROLOGICAL ANALYSIS...WEATHER
OBSERVATIONS...AND RADAR.

BASED ON 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
0345 UTC.

...SPECIAL FEATURES...
REPORTS FROM AN AIR FORCE HURRICANE HUNTER AIRCRAFT INDICATE THAT
GUSTAV HAS BECOME A HURRICANE WITH MAXIMUM WINDS NEAR 80
MPH...130 KM/HR. THIS CHANGE WILL BE REFLECTED IN THE 5 AM EDT
ADVISORY.

TROPICAL STORM GUSTAV IS CENTERED NEAR 16.8N 71.6W AT 26/0600
UTC OR ABOUT 115 NM SOUTH-SOUTHEAST OF PORT AU PRINCE HAITI
MOVING NORTHWEST AT 10 KT. ESTIMATED MINIMUM CENTRAL PRESSURE IS
990 MB. MAXIMUM SUSTAINED WIND SPEED IS 60 KT WITH GUSTS TO 75
KT. PLEASE SEE THE LATEST NHC FORECAST/ADVISORY UNDER AWIPS/WMO
HEADERS MIATCMAT2/WTNT22 KNHC AND/OR THE PUBLIC ADVISORY
MIATCPAT2/WTNT32 KNHC FOR MORE DETAILS. CLUSTERS OF SCATTERED
MODERATE/STRONG CONVECTION ARE FROM 15N-18N BETWEEN 70W-75W WITH
ISOLATED SHOWERS/THUNDERSTORMS DOTTING THE AREA N OF 13N BETWEEN
70W-76W AND N OF 17N FROM THE VIRGIN ISLANDS TO THE DOMINICAN
REPUBLIC. ADDITIONAL STRENGTHENING IS FORECAST AND GUSTAV IS
EXPECTED TO BECOME A HURRICANE LATER TODAY BEFORE REACHING THE
COAST OF HAITI LATER TODAY. GUSTAV IS EXPECTED TO PRODUCE TOTAL
RAINFALL ACCUMULATIONS OF 5 TO 7 INCHES OVER HISPANIOLA...WITH
ISOLATED MAXIMUM AMOUNTS OF UP TO 25 INCHES POSSIBLE. THESE
INTENSE RAINS MAY PRODUCE LIFE-THREATENING FLASH FLOODS AND MUD
SLIDES.

...TROPICAL WAVES...
A 1008 MB LOW IS OVER THE CAPE VERDE ISLANDS NEAR 15N24W MOVING
NW NEAR 10 KT. THIS LOW IS EMBEDDED WITHIN A BROAD AREA OF DEEP
LAYERED MOISTURE WITH ANY DEEP CONVECTION TO THE S OF THE
ISLANDS.

TROPICAL WAVE IS ANALYZED ALONG 34W S OF 19N WITH A 1009 MB LOW
ALONG THE WAVE NEAR 12N. IT APPEARS THAT THE TROPICAL WAVE HAS
LEFT THE LOW BEHIND AND WILL BE RELOCATED AT 26/0600 UTC ALONG
36W/37W. SCATTERED SHOWERS AND POSSIBLE ISOLATED THUNDERSTORMS
ARE FROM 10N-13N BETWEEN 33W-37W.

TROPICAL WAVE IS IN THE E CARIBBEAN IS ALONG 69W S OF 13N MOVING
W NEAR 20 KT. WAVE REMAINS EMBEDDED WITHIN THE DEEP LAYERED
MOISTURE BUT IS MOSTLY INLAND OVER SOUTH AMERICA...THUS NO
ASSOCIATED SHOWERS OVER THE CARIBBEAN WATERS.

TROPICAL WAVE IN THE W CARIBBEAN IS ALONG 84W/85W S OF 21N
MOVING W NEAR 20 KT. THIS WAVE IS EMBEDDED WITHIN SOME DRIER
AIR...THUS ONLY ISOLATED SHOWERS/THUNDERSTORMS ARE IN THE GULF
OF HONDURAS S OF 19N BETWEEN 84W-86W.

...THE ITCZ...
THE ITCZ AXIS IS ANALYZED ALONG 19N15W 10N37W 9N45W 12N62W.
CLUSTERS OF SCATTERED MODERATE/STRONG CONVECTION ARE WITHIN 150
NM OF LINE FROM 14N23W TO 7N31W AND WITHIN 90 NM OF LINE FROM
8N31W TO 9N41W. CLUSTERS OF SCATTERED MODERATE/ISOLATED STRONG
CONVECTION ARE FROM 15N-18N BETWEEN THE COAST OF W AFRICA TO
20W.

...DISCUSSION...

GULF OF MEXICO...
T.D. FAY REMAINS INLAND OVER CENTRAL MISSISSIPPI BUT CONTINUES
TO GENERATE ISOLATED SHOWERS/THUNDERSTORMS IN THE GULF WATERS N
OF 25N W OF 86W TO THE COAST OF TEXAS. SMALL UPPER LOW IS
CENTERED ALONG THE TEXAS COAST COVERING THE W GULF WITH AN UPPER
RIDGE EXTENDING E ACROSS MEXICO ALONG 22N OVER THE SW GULF
PROVIDING UPPER LEVEL DIFFLUENCE TO GENERATE ISOLATED SHOWERS/
THUNDERSTORMS WITHIN 75 NM ALONG THE COAST OF MEXICO FROM S OF
TUXPAN MEXICO TO THE TEXAS BORDER. AN UPPER HIGH REMAINS
ANCHORED IN THE FLORIDA STRAITS COVERING THE E GULF. THIS
SCENARIO IS KEEPING THE REMAINDER OF THE GULF MOSTLY QUIET AGAIN
TONIGHT.

CARIBBEAN SEA...
THE MAIN CONCERN TONIGHT FOR THE CARIBBEAN IS T.S. GUSTAV...SEE
SPECIAL FEATURES ABOVE. THE UPPER OUTFLOW ASSOCIATED WITH GUSTAV
IS ELONGATED E/W WITH MAINLY EASTERLY UPPER FLOW OVER THE
CARIBBEAN E OF 80W. AN UPPER RIDGE IS ANCHORED IN THE FLORIDA
STRAITS GIVING THE NW CARIBBEAN SE UPPER FLOW. THE ITCZ AXIS
CROSSES THE EXTREME S CARIBBEAN GENERATING SCATTERED SHOWERS/
ISOLATED THUNDERSTORMS WITHIN 45 NM ALONG THE COAST OF COLOMBIA
THROUGH S NICARAGUA. DEEP LAYERED MOISTURE DOMINATES THE ENTIRE
CARIBBEAN. HOWEVER...OTHER THAN THE ACTIVITY NOTED ABOVE AND
THAT ASSOCIATED WITH THE TROPICAL WAVE ALONG 84W/85W...THE SKIES
REMAIN RATHER CLEAR TONIGHT OVER THE REMAINDER OF THE AREA.

ATLANTIC OCEAN...
AN UPPER RIDGE COVERS THE FAR W ATLC ANCHORED IN THE FLORIDA
STRAITS EXTENDING A RIDGE AXIS N TO BEYOND 32N75W. BROAD UPPER
TROUGH IS OVER THE W ATLC ANCHORED N OF THE REGION COVERING THE
AREA FROM 59W-75W GENERATING SCATTERED/NUMEROUS SHOWERS WITH
SCATTERED THUNDERSTORMS FROM 22N-30N BETWEEN 57W-65W WITH
SCATTERED SHOWERS/ISOLATED THUNDERSTORMS WITHIN 120/150 NM OF
LINE FROM 23N64W OVER THE GREATER ANTILLES NEAR THE E TIP OF THE
DOMINICAN REPUBLIC. A SURFACE TROUGH IS ALSO EMBEDDED WITHIN
THIS SAME AREA EXTENDING FROM 20N64W TO 29N57W. AN UPPER RIDGE
IS ANCHORED IN THE CENTRAL ATLC NEAR 19N58W. A WEAK 1012 MB
SURFACE LOW IS BENEATH THIS UPPER RIDGE NEAR 19N53W WITH THE
UPPER LEVEL DIFFLUENCE ENHANCING SCATTERED SHOWERS/ISOLATED
THUNDERSTORMS WITHIN 225 NM OF THE SURFACE LOW. A SECOND UPPER
TROUGH COVERS THE E ATLC EXTENDING THROUGH 32N33W ALONG 22N36W
INTO THE TROPICS TO 12N46W...HOWEVER THIS IS A RATHER BENIGN
FEATURE. BROAD SURFACE RIDGE REMAINS OVER THE ATLC N OF 25N E OF
70W ANCHORED BY A SERIES OF HIGHS N OF THE REGION AND A WEAKNESS
NEAR THE SURFACE TROUGH.

$$
WALLACE





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