[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 091155
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
805 AM EDT SUN OCT 09 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1045 UTC.

...SPECIAL FEATURES...

AN AREA OF BROAD SURFACE TROUGHING OVER THE W ATLC AND E GULF OF
MEXICO IS BEING INDUCED BY AN UPPER LEVEL TROUGH THAT EXTENDS
FROM W TENNESSEE INTO THE GULF OF MEXICO TO AN UPPER LOW NEAR
25N83W SUPPORTING A SURFACE TROUGH THAT AT 09/0900 UTC EXTENDS
FROM THE N COAST OF CUBA NEAR 22N79W BETWEEN THE BAHAMAS AND
FLORIDA TO 31N79W. A LARGE AREA OF SCATTERED SHOWERS/ISOLATED
THUNDERSTORMS ARE OVER THE W ATLC S OF 30N TO OVER THE GREATER
ANTILLES FROM THE MONA PASSAGE TO E CUBA BETWEEN 68W-77W AND N
OF 24N TO BEYOND 32N BETWEEN 77W-85W.

SURFACE PRESSURES ARE SLOWLY FALLING. LITTLE CHANGE IN THE
ORGANIZATION OF THIS DISTURBANCE HAS TAKEN PLACE DURING THE LAST
SEVERAL HOURS. SOME DEVELOPMENT INTO A TROPICAL OR SUBTROPICAL
CYCLONE IS POSSIBLE DURING THE NEXT FEW DAYS AS IT MOVES
NORTHWESTWARD 5 TO 10 MPH. REGARDLESS OF DEVELOPMENT...STRONG
GUSTY WINDS AND LOCALLY HEAVY RAINFALL ARE EXPECTED OVER THE
NORTHERN BAHAMAS AND PORTIONS OF THE FLORIDA PENINSULA TODAY.
THESE CONDITIONS ARE EXPECTED TO SPREAD NORTHWARD INTO EASTERN
PORTIONS OF GEORGIA AND SOUTH CAROLINA DURING THE NEXT DAY OR
TWO. FOR ADDITIONAL INFORMATION SPECIFIC TO YOUR AREA...PLEASE
SEE STATEMENTS ISSUED BY YOUR LOCAL WEATHER OFFICE.

...TROPICAL WAVES...

TROPICAL WAVE IS ANALYZED FROM 17N52W ALONG 11N53W TO 6N53W
MOVING W 10-15 KT. WAVE IS EMBEDDED WITHIN A SPIKE OF DEEP
LAYER MOISTURE AS DEPICTED ON THE TOTAL PRECIPITABLE WATER
IMAGERY. WAVE IS CO-LOCATED WITH AN UPPER LEVEL TROUGH WITH
SCATTERED SHOWERS WITHIN 90 NM EITHER SIDE OF THE WAVE AXIS N OF
11N.

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

THE MONSOON TROUGH EXTENDS INTO THE E TROPICAL ATLC NEAR 17N16W
ALONG 17N19W THEN S ALONG 10N22W TO 8N25W. THE ITCZ EXTENDS FROM
7N27W ALONG 6N35W 9N42W TO 9N51W. CLUSTERS OF SCATTERED
MODERATE/STRONG CONVECTION ARE OFF THE COAST OF W AFRICA FROM
4N-9N BETWEEN 9W-19W. CLUSTERS OF SCATTERED MODERATE/ISOLATED
STRONG CONVECTION ARE FROM 2N-10N BETWEEN 28W-39W AND FROM
5N-12N BETWEEN 41W-52W.

...DISCUSSION...

GULF OF MEXICO...
A SHARP UPPER TROUGH ASSOCIATED WITH THE AREA DESCRIBED IN THE
SPECIAL FEATURES SECTION COVERS THE E GULF E OF 90W. A BROAD
UPPER RIDGE EXTENDS FROM THE E PACIFIC REGION ACROSS S MEXICO
AND THE W GULF FROM NEAR VERACRUZ TO THE LOUISIANA/TEXAS BORDER
ENHANCING THE ACTIVITY INLAND OVER TEXAS AND WITHIN 60 NM ALONG
THE COAST OF TEXAS BETWEEN GALVESTON AND MATAGORDA BAY. A BROAD
SURFACE RIDGE COVERS THE GULF ANCHORED OVER THE MID ATLC STATES
WITH A RIDGE AXIS EXTENDING ACROSS N GEORGIA TO S ALABAMA INTO
THE GULF TO NEAR 25N94W. TIGHT PRESSURE GRADIENT BETWEEN THIS
SURFACE RIDGE AND A SURFACE TROUGH IN THE W ATLC IS PRODUCING
STRONG EASTERLY SURFACE FLOW TO GALE FORCE OVER THE GULF AND
WILL PERSIST THROUGH TONIGHT. THIS SURFACE FLOW IS GENERATING
SCATTERED SHOWERS AND POSSIBLE ISOLATED THUNDERSTORMS OVER THE N
GULF N OF 25N W OF 85W. A SURFACE LOW IS EXPECTED TO DEVELOP
OVER THE E GULF LATER TODAY. THE LOW WILL DRIFT NW ACROSS NE
GULF THROUGH MON SUBSIDING WINDS AS IT MOVES INLAND OVER NW
FLORIDA. A WEAK TROUGH WILL EXTEND FROM LOW SW TO YUCATAN TUE
AND WED THEN SHIFT E ACROSS FLORIDA AND SE GULF THU.

CARIBBEAN SEA...
THE UPPER TROUGH OVER THE GULF OF MEXICO EXTENDS OVER THE W
CARIBBEAN THROUGH THE YUCATAN CHANNEL TO OVER HONDURAS AND
NICARAGUA DRAWING TROPICAL MOISTURE N OVER THE CENTRAL CARIBBEAN
GENERATING SCATTERED SHOWERS/ISOLATED THUNDERSTORMS N OF 15N TO
OVER CUBA BETWEEN 76W-80W. AN UPPER RIDGE EXTENDS OVER THE E
CARIBBEAN EXTENDING FROM THE COAST OF VENEZUELA NEAR 11N69W
THROUGH THE MONA PASSAGE ENHANCING SCATTERED SHOWERS/
THUNDERSTORMS OVER THE CENTRAL CARIBBEAN BETWEEN 68W-76W. THE
MONSOON TROUGH EXTENDS FROM COLOMBIA NEAR 12N71W ALONG 12N76W
ACROSS S NICARAGUA INTO THE E PACIFIC REGION NEAR 11N84W
GENERATING SCATTERED SHOWERS/ISOLATED THUNDERSTORMS S OF 13N
BETWEEN 75W-80W AND S OF 10N BETWEEN 80W-84W. THIS IS LEAVING
THE FAR E AND FAR W CARIBBEAN UNDER MOSTLY CLEAR SKIES THIS
MORNING. THE WEAK PRESSURE PATTERN WILL PERSIST THROUGH THU.

ATLANTIC OCEAN...
THE UPPER TROUGH OVER THE E GULF OF MEXICO EXTENDS OVER THE FAR
W ATLC W OF 77W AND IS ASSOCIATED WITH THE AREA IN THE SPECIAL
FEATURES SECTION ABOVE. A BROAD UPPER RIDGE COVERS THE REMAINDER
OF THE W ATLC BETWEEN 55W-76W ENHANCING THE ACTIVITY IN THE
SPECIAL FEATURES. A BROAD SURFACE RIDGE COVERS THE W AND CENTRAL
ATLC N OF 24N W OF 50W TO OVER THE E CONUS AND GULF OF MEXICO
ANCHORED OVER THE MID ATLC STATES. TIGHT PRESSURE GRADIENT
BETWEEN THIS SURFACE RIDGE AND THE SURFACE TROUGH OVER THE W
ATLC IS GIVING THE FAR W ATLC STRONG EASTERLY WINDS TO GALE
FORCE. AN UPPER TROUGH COVERS THE NW ATLC INTO THE CENTRAL ATLC
N OF 26N BETWEEN 41W-60W SUPPORTING A COLD FRONT THAT ENTERS THE
REGION NEAR 32N41W ALONG 27N45W TO 24N52W WHERE IT CONTINUES AS
A SURFACE TROUGH ALONG 23N61W TO 23N67W. SCATTERED SHOWERS AND
POSSIBLE ISOLATED THUNDERSTORMS ARE WITHIN 60/90 NM E OF THE
FRONT AND WITHIN 45 NM EITHER SIDE OF THE SURFACE TROUGH. A
SURFACE RIDGE COVERS THE E ATLC WITH THE AXIS EXTENDING THROUGH
32N30W ALONG 26N36W TO A 1017 MB HIGH NEAR 22N45W. STRONG
SURFACE RIDGE OVER THE W ATLC WILL MAINTAIN STRONG NE WINDS
THROUGH MON.

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

$$
PAW






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