[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 130545
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
105 AM EST THU DEC 13 2012

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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1115 UTC.

...ITCZ/MONSOON TROUGH...
THE MONSOON TROUGH EXTENDS FROM THE AFRICAN COAST NEAR 07N12W TO
05N16W. THE INTERTROPICAL CONVERGENCE ZONE AXIS EXTENDS FROM
05N16W TO 05N26W TO 02N46W. SCATTERED MODERATE CONVECTION IS
FROM 02N-08N BETWEEN 12W-19W...AND WITHIN 90 NM EITHER SIDE OF
THE ITCZ AXIS BETWEEN 19W AND 39W.

...DISCUSSION...

GULF OF MEXICO...
A MIDDLE TO UPPER LEVEL SHORTWAVE TROUGH IS NOTED ON WATER VAPOR
IMAGERY OVER THE SE CONUS WITH AXIS EXTENDING FROM OVER THE
TENNESSEE RIVER VALLEY SOUTHWARD TO OVER THE NORTHERN FLORIDA
PENINSULA. THIS TROUGHING SUPPORTS A STATIONARY FRONT ANALYZED
FROM THE CENTRAL FLORIDA PENINSULA SW INTO THE GULF FROM TAMPA
BAY TO 23N90W TO THE SOUTHERN MEXICO COAST NEAR 19N95W. THE
FRONT HAS CONTINUED TO BECOME MORE DIFFUSE OVER THE PAST 24
HOURS WITH POSSIBLE ISOLATED SHOWERS OCCURRING WITHIN 90 NM
EITHER SIDE OF THE BOUNDARY. TO THE NW OF THE FRONT...SKIES
CONTINUE TO CLEAR AS THE MIDDLE TO UPPER LEVELS OF THE
ATMOSPHERE REMAIN DRY AND STABLE THIS EVENING WITH A RIDGE
BUILDING IN ACROSS THE SE CONUS AND WESTERN GULF WATERS. THE
FRONT IS EXPECTED TO CONTINUE DISSIPATING OVER THE SE GULF LATER
TODAY WITH NORTH-NORTHEASTERLY WINDS PERSISTING E OF 95W.

CARIBBEAN SEA...
AN UPPER LEVEL ANTICYCLONIC CIRCULATION IS CENTERED OVER THE SW
CARIBBEAN NEAR 11N79W AND CONTINUES TO PROVIDE A RELATIVELY
STABLE AND TRANQUIL ATMOSPHERE ACROSS MUCH OF THE BASIN THIS
EVENING. WEST-NORTHWESTERLY FLOW ALOFT WITHIN DRY AIR AND
SUBSIDENCE IS KEEPING SKIES FAIR WITH THE MAIN IMPACT BEING
ENHANCED TRADE WINDS GENERALLY E OF 80W. THE PRESSURE GRADIENT
IS EXPECTED TO MAINTAIN THESE TRADES THROUGH EARLY FRIDAY AS
STRONG RIDGING OVER THE SW NORTH AND CENTRAL ATLC BEGINS TO
SLOWLY ERODE AND SHIFT EASTWARD ON THURSDAY. OTHERWISE...A FEW
PASSING ISOLATED SHOWERS ARE NOTED ON SATELLITE IMAGERY FROM
13N-18N BETWEEN 75W-82W...AND ACROSS PORTIONS OF THE LEEWARD
ISLANDS N OF 15N E OF 65W.

ATLANTIC OCEAN...
A MIDDLE TO UPPER LEVEL SHORTWAVE TROUGH IS PROGRESSING EAST-
NORTHEASTWARD OVER THE SE CONUS AND SUPPORTS A WEAK 1015 MB LOW
CENTERED NEAR 32N77W. A STATIONARY FRONT EXTENDS SW FROM THE LOW
CENTER TO THE FLORIDA PENINSULA NEAR CAPE CANAVERAL WITH WIDELY
SCATTERED SHOWERS AND ISOLATED TSTMS OCCURRING N OF 27N W OF
72W. THE REMAINDER OF THE SW NORTH ATLC AND CENTRAL ATLC IS
UNDER THE INFLUENCE OF A RIDGE ANCHORED BY A 1027 MB HIGH
CENTERED NEAR 31N55W. A COUPLE AREAS OF LOW-LEVEL MOISTURE AND
EMBEDDED LOW-TOPPED ISOLATED SHOWERS ARE MOVING WESTWARD ON THE
SOUTHWESTERN PERIPHERY OF THE RIDGE IMPACTING THE LEEWARD
ISLANDS AND AREAS S OF 22N BETWEEN 58W-65W...AND AN AREA EAST OF
THE TURKS AND CAICOS ISLANDS FROM 19N-25N BETWEEN 67W-72W.
OTHERWISE...A MIDDLE TO UPPER LEVEL LOW IS CENTERED OVER THE
CENTRAL ATLC NEAR 20N50W THAT CONTINUES TO SUPPORT A SURFACE
TROUGH ANALYZED FROM 11N52W TO 17N46W. LOW-LEVEL MOISTURE
CONVERGENCE IN THE VICINITY OF THE SURFACE TROUGH ALONG WITH
MAXIMIZED MIDDLE TO UPPER LEVEL DIFFLUENCE EAST OF THE UPPER
LEVEL LOW IS GENERATING A LARGE AREA OF SCATTERED SHOWERS AND
ISOLATED TSTMS FROM 09N-24N BETWEEN 35W-51W. TO THE NORTH OF
THIS AREA...SURFACE RIDGING DOMINATES ANCHORED BY A 1028 MB HIGH
CENTERED NEAR 31N39W.

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

$$
HUFFMAN



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