[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 122318
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
705 PM EST SAT NOV 12 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
2300 UTC.

...ITCZ/MONSOON TROUGH...

THE MONSOON TROUGH EXTENDS ACROSS AFRICA INTO THE E TROPICAL
ATLC ALONG 12N16W 8N19W 6N26W. THE ITCZ CONTINUES FROM 6N26W
ALONG 7N38W 7N50W. SCATTERED MODERATE/ISOLATED STRONG CONVECTION
IS FROM 6N-10N BETWEEN 32W-41W.

...DISCUSSION...

GULF OF MEXICO...
A SURFACE RIDGE CONTINUES TO DOMINATE THE GULF OF MEXICO THIS
EVENING ANCHORED BY A 1027 MB HIGH OVER SW GEORGIA WITH AXIS
EXTENDING FROM THE NE GULF TO THE SW GULF. ANTI-CYCLONIC SURFACE
FLOW OF 10-15 KTS IS AROUND THE RIDGE REACHING 20 KTS ALONG THE
TEXAS COAST. CLUSTERS OF STRATOCUMULUS CLOUDS COVER MUCH OF THE
BASIN WITH THE CLEAREST SKIES OVER THE FAR ERN GULF. ALOFT...AN
UPPER LEVEL RIDGE EXTENDS ACROSS MUCH OF MEXICO AND INTO THE ERN
CONUS SUPPORTING THE SURFACE RIDGE. WATER VAPOR IMAGERY
INDICATES VERY DRY AIR ALOFT OVER THE MAJORITY OF THE BASIN
EXCEPT FOR A LITTLE MOISTURE PRESENT OVER THE FAR NW CORNER.
EXPECT SURFACE RIDGING TO REMAIN ACROSS THE BASIN FOR THE NEXT
COUPLE OF DAYS.

CARIBBEAN SEA...
DRY AIR ALOFT OVER THE GULF OF MEXICO EXTENDS OVER THE NW
CARIBBEAN MAINTAINING FAIR CONDITIONS WITH A FEW LOW-LEVEL
STRATOCUMULUS CLOUDS. ISOLATED SHOWERS ARE NOTED ACROSS BELIZE
AND NRN HONDURAS ASSOCIATED WITH A SMALL AREA OF MOISTURE LEFT
BEHIND BY A FRONTAL BOUNDARY THAT DISSIPATED LAST NIGHT.
ALOFT...AN UPPER LEVEL TROUGH EXTENDS FROM THE W ATLC ACROSS WRN
CUBA TO HONDURAS WITH UPPER LEVEL RIDGING COVERING THE REMAINDER
OF THE BASIN CENTERED NEAR 17N69W. THIS PATTERN IS CREATING AN
AREA OF DIFFLUENCE ALOFT WITH MOIST SWLY FLOW FROM THE SW
CARIBBEAN TO THE WINDWARD PASSAGE. THIS COMBINED WITH THE
MONSOON TROUGH WHICH EXTENDS FROM THE COSTA RICA/PANAMA BORDER
TO NRN COLOMBIA...AND A LOW-MID LEVEL TROUGH S OF JAMAICA IS
CAUSING SCATTERED SHOWERS/THUNDERSTORMS S OF 16N BETWEEN
72W-83W. SHOWER/THUNDERSTORM ACTIVITY WILL LIKELY REMAIN IN THIS
AREA OVER THE NEXT DAY OR SO AND BEGIN TO ADVECT WWD IN THE E
PACIFIC. SCATTERED SHOWERS/THUNDERSTORMS ARE ALSO OVER THE
DOMINICAN REPUBLIC INFLUENCED BY THE UPPER LEVEL TROUGH. THE ERN
CARIBBEAN IS UNDER MOSTLY FAIR CONDITIONS DUE TO DRY AIR ALOFT.
A WEAK SURFACE TROUGH IS JUST W OF THE WINDWARD ISLANDS
ASSOCIATED WITH AN AREA OF LOW LEVEL MOISTURE SUPPORTING
SCATTERED SHOWERS/ISOLATED THUNDERSTORMS S OF 61N E OF 64W.

ATLANTIC OCEAN...
SURFACE RIDGING AND DRY AIR ALOFT ARE KEEPING THE FAR WRN ATLC
UNDER FAIR CONDITIONS. AN UPPER LEVEL TROUGH ALONG 35N72W TO WRN
CUBA IS SUPPORTING A COLD FRONT ALONG 32N52W 27N61W 24N70W
BECOMING STATIONARY TO ERN CUBA NEAR 21N77W. ISOLATED SHOWERS
ARE WITHIN 30 NM OF THE AXIS. AN AREA OF SCATTERED
SHOWERS/THUNDERSTORMS IS ALSO S OF THE FRONT ALONG A LINE FROM
20N70W TO 23N65W. ACROSS THE ERN ATLC...AN UPPER LEVEL RIDGE
EXTENDS FROM THE ERN CARIBBEAN TO NEAR 41N42W SUPPORTING A 1024
MB SURFACE HIGH NEAR 35N40W. A SHORTWAVE UPPER LEVEL TROUGH IS
JUST E OF THE RIDGE FROM 24N51W TO 13N59W SUPPORTING SCATTERED
SHOWERS/THUNDERSTORMS E OF THE WINDWARD ISLANDS FROM 8N14N
BETWEEN 53W-63W. A SECOND UPPER TROUGH IS FARTHER E EXTENDING
BETWEEN THE AZORES ISLANDS AND CANARY ISLANDS TO W OF THE CAPE
VERDE ISLANDS SUPPORTING A COLD FRONT THAT ENTERS THE DISCUSSION
AREA NEAR 32N12W TO 26N15W. A WEAK 1011 MB SURFACE LOW IS ALSO
EMBEDDED WITHIN THE SURFACE RIDGE NEAR 20N35W. EXPECT THE
SOUTHERN PORTION OF THE FRONTAL BOUNDARY IN THE CENTRAL/WRN ATLC
TO BEGIN TO DISSIPATE WHILE THE NRN PORTION CONTINUES TO PUSH
EWD.


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

$$
WALTON







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