[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 311742
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
205 PM EDT WED AUG 31 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1715 UTC.

...SPECIAL FEATURE...
TROPICAL STORM KATIA IS CENTERED NEAR 14.2N 40.8W AS OF 31/1500
UTC OR ABOUT 955 NM W OF THE SOUTHERNMOST CAPE VERDE ISLANDS
MOVING WNW AT 18 KT. ESTIMATED MINIMUM CENTRAL PRESSURE IS 994
MB. MAXIMUM SUSTAINED WIND SPEED IS 55 KT WITH GUSTS TO 65 KT.
PLEASE SEE THE LATEST INTERMEDIATE PUBLIC ADVISORY UNDER
AWIPS/WMO HEADER MIATCPAT2/WTNT32 KNHC AND THE FULL FORECAST/
ADVISORY UNDER AWIPS/WMO HEADER MIATCMAT2/WTNT22 KNHC FOR MORE
DETAILS. SCATTERED MODERATE/ISOLATED STRONG CONVECTION COVERS
THE AREA FROM 11N-16N BETWEEN 39W-44W.

TROPICAL WAVE IS OVER THE SE GULF OF MEXICO AND THE YUCATAN
PENINSULA FROM 26N85W TO BELIZE NEAR 18N87W MOVING W-NW NEAR 15
KT. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS WITHIN
75/90 NM OF LINE FROM THE WAVE AXIS NEAR 24N86W INTO THE NW
CARIBBEAN TO 20N85W. ALTHOUGH UPPER LEVEL WINDS ARE NOT
FAVORABLE FOR SIGNIFICANT DEVELOPMENT DURING THE NEXT DAY OR
TWO...THERE IS SOME POTENTIAL FOR TROPICAL OR SUBTROPICAL
CYCLONE DEVELOPMENT OVER THE CENTRAL OR WESTERN GULF OF MEXICO
IN A FEW DAYS. THIS SYSTEM HAS A MEDIUM CHANCE OF BECOMING A
TROPICAL OR SUBTROPICAL CYCLONE DURING THE NEXT 48 HOURS.

...TROPICAL WAVES...
THE TROPICAL WAVE IN THE SE GULF OF MEXICO IS NOW IN THE SPECIAL
FEATURES SECTION ABOVE.

...THE ITCZ/THE MONSOON TROUGH...
THE MONSOON TROUGH IS ANALYZED ACROSS AFRICA ENTERING THE E
PACIFIC REGION JUST S OF DAKAR SENEGAL EXTENDING ALONG 13N20W TO
12N27W AND IS DISRUPTED TO THE W BY T.S. KATIA. CLUSTERS OF
SCATTERED MODERATE CONVECTION 4N-8N BETWEEN E OF 32W TO INLAND
OVER SIERRA LEONE AND LIBERIA AND FROM 9N-15N E OF 23W TO INLAND
OVER GUINEA TO SENEGAL.

...DISCUSSION...

GULF OF MEXICO...
AN ABUNDANCE OF DEEP LAYER MOISTURE COVERS ALL BUT THE NW GULF
WITH A SHORTWAVE UPPER TROUGH EXTENDING ACROSS THE N GULF FROM
THE W ATLC ACROSS THE FLORIDA PANHANDLE INTO THE GULF NEAR
PENSACOLA TO CORPUS CHRISTI TEXAS GENERATING SCATTERED SHOWERS/
ISOLATED THUNDERSTORMS N OF 27N E OF 87W TO INLAND OVER FLORIDA.
AN UPPER RIDGE DOMINATES THE REMAINDER OF THE GULF ANCHORED
INLAND OVER S/CENTRAL TEXAS EXTENDING AN AXIS TO W CUBA/THE
STRAITS OF FLORIDA. SCATTERED SHOWERS/ISOLATED THUNDERSTORMS ARE
BEING ENHANCED BY THE TROPICAL WAVE MOVING THROUGH THE UPPER
RIDGE COVERING THE AREA S OF 27W W OF 85W TO OVER THE FLORIDA
PENINSULA AND THROUGH THE STRAITS OF FLORIDA INCLUDING THE
FLORIDA KEYS. A SURFACE TROUGH OVER THE SW GULF EXTENDS FROM
23N96W TO THE W BAY OF CAMPECHE NEAR 19N95W GENERATING SCATTERED
SHOWERS/THUNDERSTORMS WITHIN 90/120 NM OF LINE FROM 20N94W TO
25N97W. THIS LEAVES ONLY THE NW GULF WITH CLEAR SKIES THIS
AFTERNOON.

CARIBBEAN SEA...
AN ABUNDANCE OF DEEP LAYER MOISTURE COVERS THE W CARIBBEAN WHERE
AN UPPER RIDGE EXTENDING FROM S/CENTRAL MEXICO ACROSS THE S GULF
OF MEXICO TO OVER CUBA IS GIVING THE NW CARIBBEAN NE FLOW ALOFT.
AN INVERTED UPPER TROUGH EXTENDS ACROSS THE CENTRAL CARIBBEAN
FROM CENTRAL PANAMA TO THE WINDWARD PASSAGE ENHANCING THE NE
FLOW OVER THE NW CARIBBEAN AND THE SCATTERED/HEAVY SHOWERS WITH
SCATTERED THUNDERSTORMS W OF A LINE FROM 17N94W ALONG 13N81W TO
CENTRAL PANAMA NEAR 9N79W TO INLAND OVER CENTRAL AMERICA. SOME
ISOLATED SHOWERS/THUNDERSTORMS ARE POSSIBLE OVER THE REMAINDER
OF THE CARIBBEAN W OF 75W LEAVING THE E CARIBBEAN UNDER MOSTLY
CLEAR SKIES THIS AFTERNOON.

ATLANTIC OCEAN...
THE PRIMARY FEATURE OF INTEREST IS TROPICAL STORM KATIA IN THE
CENTRAL TROPICAL ATLC...SEE SPECIAL FEATURES SECTION ABOVE. AN
UPPER LOW IS JUST N OF THE DISCUSSION AREA NEAR 34N69W EXTENDING
A SHORTWAVE UPPER TROUGH SW ACROSS SE GEORGIA/NE FLORIDA INTO
THE GULF OF MEXICO GENERATING SCATTERED SHOWERS/ISOLATED
THUNDERSTORMS WITHIN 120 NM S OF A LINE FROM 31N71W 30N76W TO
31N81W. THE UPPER RIDGE OVER THE GULF OF MEXICO EXTENDS ACROSS
THE REMAINDER OF THE W ATLC FROM W CUBA NEAR HAVANA NE ALONG
27N74W TO BEYOND 32N68W. A BROAD UPPER TROUGH COVERS THE CENTRAL
ATLC RE-ENFORCING THE N FLOW BETWEEN 65W-72W WHERE A SURFACE
TROUGH EXTENDS FROM 30N65W TO 22N69W GENERATING SCATTERED
SHOWERS/ISOLATED THUNDERSTORMS FROM 22N-25N BETWEEN 65W-69W AND
ISOLATED SHOWERS WITHIN 200 NM W OF THE TROUGH N OF 27N. THE
UPPER TROUGH MENTIONED ABOVE EXTENDS FROM AN UPPER LOW NEAR
30N55W SW TO THE VIRGIN ISLANDS SUPPORTING A SURFACE TROUGH THAT
EXTENDS FROM 32N52W TO 26N56W, SCATTERED SHOWERS/THUNDERSTORMS
ARE WITHIN 150 NM OF LINE FROM 21N55W TO 31N49W AND N OF 30N
BETWEEN 50W-56W. A SURFACE RIDGE COVERS THE CENTRAL INTO THE E
ATLC ANCHORED BY A 1026 MB HIGH N OF THE DISCUSSION AREA THROUGH
32N39W TO 21N34W. A BROAD UPPER TROUGH IS MOVING S INTO THE E
ATLC SUPPORTING A DEVELOPING COLD FRONT JUST N OF THE REGION
WITH SCATTERED SHOWERS N OF 30N BETWEEN 18W-31W.

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

$$
PAW





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