[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 131145
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
705 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1115 UTC.

...ITCZ/MONSOON TROUGH...
THE MONSOON TROUGH EXTENDS FROM THE AFRICAN COAST NEAR 08N13W TO
04N16W. THE INTERTROPICAL CONVERGENCE ZONE AXIS EXTENDS FROM
04N16W TO 03N32W TO 01N47W. SCATTERED MODERATE CONVECTION IS
FROM 01N-06N BETWEEN 11W-40W.

...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
CAROLINAS SOUTHWARD TO NEAR 31N79W. THIS TROUGHING SUPPORTS A
STATIONARY FRONT ANALYZED FROM THE CENTRAL FLORIDA PENINSULA SW
INTO THE GULF FROM 27N82W TO 22N90W TO THE SOUTHERN MEXICO COAST
NEAR 19N95W. THE FRONT HAS CONTINUED TO BECOME MORE DIFFUSE OVER
THE PAST 24 TO 36 HOURS WITH POSSIBLE ISOLATED SHOWERS OCCURRING
WITHIN 90 NM EITHER SIDE OF THE BOUNDARY. TO THE NW OF THE FRONT
BETWEEN 85W AND 96W...SKIES CONTINUE TO CLEAR AS THE MIDDLE TO
UPPER LEVELS OF THE ATMOSPHERE REMAIN DRY AND STABLE THIS
MORNING. A RIDGE CONTINUES BUILDING IN ACROSS THE SE CONUS AND
WESTERN GULF WATERS AND IS EXPECTED TO PROVIDE PERSISTENT NORTH-
NORTHEASTERLY WINDS E OF 95W THROUGHOUT THE DAY TODAY AS THE
FRONT CONTINUES TO DISSIPATE OVER SE PORTIONS OF THE BASIN.

CARIBBEAN SEA...
AN UPPER LEVEL ANTICYCLONIC CIRCULATION IS CENTERED OVER THE SW
CARIBBEAN NEAR 11N83W AND CONTINUES TO PROVIDE A RELATIVELY
STABLE AND TRANQUIL ATMOSPHERE ACROSS MUCH OF THE BASIN THIS
MORNING. WEST-NORTHWESTERLY FLOW ALOFT WITHIN DRY AIR AND
SUBSIDENCE IS KEEPING SKIES MOSTLY 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 AND TSTMS ARE NOTED
ON SATELLITE IMAGERY FROM 12N-16N BETWEEN 67W-84W...AND ACROSS
PORTIONS OF THE NE CARIBBEAN NE OF A LINE FROM 14N61W TO THE
MONA PASSAGE NEAR 18N68W...INCLUDING PUERTO RICO...AND THE
LEEWARD ISLANDS.

ATLANTIC OCEAN...
A MIDDLE TO UPPER LEVEL SHORTWAVE TROUGH IS PROGRESSING EAST-
NORTHEASTWARD OVER THE SE CONUS AND SUPPORTS A 1013 MB LOW
CENTERED NEAR 34N74W. A STATIONARY FRONT EXTENDS SW FROM THE LOW
CENTER TO 30N80W THEN TO THE FLORIDA PENINSULA NEAR 29N81W WITH
WIDELY SCATTERED SHOWERS AND ISOLATED TSTMS OCCURRING N OF 28N W
OF 69W. THE REMAINDER OF THE SW NORTH ATLC AND CENTRAL ATLC IS
UNDER THE INFLUENCE OF A RIDGE ANCHORED BY A 1025 MB HIGH
CENTERED NEAR 31N53W. 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 AREA S OF 22N BETWEEN 60W-67W...AND AN AREA IN THE
VICINITY OF THE TURKS AND CAICOS ISLANDS FROM 19N-25N BETWEEN
68W-73W. OTHERWISE...A MIDDLE TO UPPER LEVEL LOW IS CENTERED
OVER THE CENTRAL ATLC NEAR 19N51W THAT CONTINUES TO SUPPORT A
SURFACE TROUGH ANALYZED FROM 10N50W TO 20N43W. 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-25N BETWEEN 34W-51W. TO THE NORTH OF
THIS AREA...SURFACE RIDGING DOMINATES ANCHORED BY A 1025 MB HIGH
CENTERED NEAR 30N34W.

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

$$
HUFFMAN



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