[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 162340
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
705 PM EST WED NOV 16 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.

...TROPICAL WAVES...

A TROPICAL WAVE EXTENDS FROM 15N43W TO 4N45W MOVING WNW AT 10-15
KT. THE WAVE LIES JUST W OF A SURGE OF DEEP LAYER MOISTURE
EVIDENT IN TOTAL PRECIPITABLE WATER IMAGERY. AN UPPER LEVEL
TROUGH EXTENDING FROM THE CENTRAL ATLC TO THE LESSER ANTILLES IS
PLACING DIFFLUENCE ALOFT OVER THE AREA BETWEEN
37W-60W...INCLUDING THE WAVE. THIS MAKES IT DIFFICULT TO DISCERN
WHETHER CONVECTION NEAR THE WAVE IS ASSOCIATED DIRECTLY WITH THE
WAVE OR THE UPPER LEVEL PATTERN. REGARDLESS OF THE
INFLUENCE...SCATTERED MODERATE/STRONG CONVECTION IS FROM 7N-13N
BETWEEN 40W-48W.

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

THE MONSOON TROUGH EXTENDS ACROSS W AFRICA ENTERING OVER ATLC
WATERS NEAR 12N16W TO 9N19W. THE ITCZ CONTINUES FROM 9N19W ALONG
5N28W 7N40W PICKING UP ON THE OTHER SIDE OF THE TROPICAL WAVE
ALONG 6N46W TO 9N57W. SCATTERED MODERATE/STRONG CONVECTION IS
FROM 5N-9N BETWEEN 19W-32W. SIMILAR ACTIVITY IS FROM 5N-8N
BETWEEN 34W-39W.

...DISCUSSION...

THE GULF OF MEXICO...
A FAST MOVING SQUALL LINE IS CONTINUING TO IMPACT THE SE CONUS
AND NE GULF OF MEXICO THIS EVENING EXTENDING FROM THE FLORIDA
PANHANDLE NEAR PANAMA CITY TO 28N88W. THE REMAINDER OF THE BASIN
IS STILL UNDER THE INFLUENCE OF WEAK SURFACE RIDGING EXTENDING
FROM THE W ATLC AND DRY AIR ALOFT WHICH ARE MAINTAINING FAIR
CONDITIONS. SURFACE SE-S WINDS OF 10-15 KTS ARE AROUND THE RIDGE
WITH STRONGER WINDS LIKELY NEAR THE SQUALL LINE. ALOFT...MAINLY
SWLY FLOW DOMINATES AROUND AN UPPER LEVEL RIDGE OVER THE WRN
ATLC AND WRN CARIBBEAN. AN UPPER LEVEL TROUGH MOVING INTO THE
CENTRAL CONUS WILL SUPPORT A COLD FRONT THAT IS EXPECTED TO
ENTER THE GULF WITHIN THE NEXT 24 HOURS AND MOVE QUICKLY EWD
BEFORE ANOTHER SURFACE RIDGE BUILDS LATE IN THE WEEK AND INTO
THE WEEKEND.

THE CARIBBEAN SEA...
DRY AIR AND SUBSIDENCE COVER MUCH OF THE CARIBBEAN THIS EVENING
AROUND AN UPPER LEVEL RIDGE CENTERED OVER THE BAHAMAS HELPING
MAINTAIN FAIR CONDITIONS BASIN-WIDE. A FEW ISOLATED SHOWERS ARE
NOTED OVER PORTIONS OF HISPANIOLA...JAMAICA...AND ERN CUBA.
SCATTERED SHOWERS/THUNDERSTORMS ARE ALSO OVER PANAMA...COSTA
RICA...NICARAGUA AND HONDURAS. SOME OF THIS ACTIVITY IS
ASSOCIATED WITH THE MONSOON TROUGH THAT EXTENDS ACROSS NRN COSTA
RICA TO NRN COLOMBIA. AT THE SURFACE...TRADEWIND FLOW OF 15-20
KTS COVERS MUCH OF THE BASIN. EXPECT SHOWER ACTIVITY TO REMAIN
NEAR THE MONSOON TROUGH AND ACROSS CENTRAL AMERICA WITH POSSIBLE
SHOWERS ALSO OVER THE WINDWARD ISLANDS ASSOCIATED WITH AN AREA
OF MOISTURE CURRENTLY TO THE E OF THE ISLANDS.

THE ATLANTIC OCEAN...
THE WRN ATLC IS EXPERIENCING MOSTLY FAIR WEATHER AROUND A
SURFACE RIDGE EXTENDING FROM A 1025 MB HIGH NEAR 35N42W WITH
AXIS EXTENDING TOWARD S FLORIDA. ALOFT...AN UPPER LEVEL RIDGE IS
CENTERED OVER THE BAHAMAS ACCOMPANIED BY DRY AIR WHICH IS
HELPING MAINTAIN THE FAIR CONDITIONS. FARTHER E...A SHARP UPPER
TROUGH EXTENDS FROM NEAR 32N46W TO THE LESSER ANTILLES. UPPER
LEVEL DIFFLUENCE AROUND THE E SIDE OF THE TROUGH IS HELPING
SUPPORT A BROAD AREA OF SHOWERS/THUNDERSTORMS FROM N OF THE ITCZ
TO 20N BETWEEN 40W-60W...AND N OF 20N BETWEEN 40W-50W. SOME OF
THE ACTIVITY IS ALSO ENHANCED BY A SURFACE TROUGH EXTENDING FROM
27N47W TO 18N49W...A SECOND SURFACE TROUGH E OF THE WINDWARD
ISLANDS ALONG 14N58W TO 8N59W...AND A TROPICAL WAVE ALONG 15N43W
TO 4N45W. THE ERN ATLC IS COVERED BY AN UPPER LEVEL RIDGE
CENTERED NEAR 8N25W MAINTAINING MOSTLY FAIR WEATHER. A SHORTWAVE
UPPER TROUGH N OF THE DISCUSSION AREA BETWEEN THE AZORES ISLANDS
AND THE CANARY ISLANDS IS SUPPORTING A COLD FRONT ALONG 32N16W
TO 28N23W WITH ISOLATED SHOWERS ALONG THE AXIS. EXPECT
SHOWERS/POSSIBLE THUNDERSTORMS TO REMAIN ACROSS THE CENTRAL ATLC
FOR THE NEXT SEVERAL DAYS.

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

$$
WALTON







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