[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 122357
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
705 PM EST SAT DEC 12 2009

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...METEOROLOGICAL ANALYSIS...WEATHER
OBSERVATIONS...AND RADAR.

BASED ON 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
2315 UTC.

...ITCZ...

THE ITCZ AXIS IS CENTERED ALONG 8N13W 2N30W TO THE EQUATOR NEAR
50W. ISOLATED MODERATE CONVECTION IS FROM 2N-6N BETWEEN 36W-44W.

...DISCUSSION...

GULF OF MEXICO...
AS OF 2100 UTC...A STATIONARY FRONT EXTENDS ACROSS THE FLORIDA
PENINSULA FROM NEAR DEERFIELD BEACH TO VENICE...AND ENTERS THE
EASTERN GULF TO 29N87W WHERE IT CONTINUES WESTWARD AS A WARM
FRONT ALONG THE LOUISIANA GULF COAST TO A 1014 MB LOW CENTERED
NEAR FREEPORT TEXAS. A COLD FRONT EXTENDS FROM THE LOW ALONG
25N95W TO 23N98W AND INLAND ACROSS NE MEXICO. A SURFACE TROUGH
IS ALSO ANALYZED FROM THE COLD FRONT NEAR 24N95W TO SOUTHERN
MEXICO NEAR 18N92W. SCATTERED SHOWERS AND ISOLATED TSTMS ARE
OCCURRING OVER PORTIONS OF THE NW AND N/CENTRAL GULF FOCUSED
MAINLY NEAR AND SOUTH OF THE WARM FRONT N OF 26N BETWEEN
87W-95W...AND ACROSS NORTHERN FLORIDA. POSSIBLE ISOLATED SHOWERS
ARE WITHIN 90 NM EITHER SIDE OF THE COLD FRONT AND SURFACE
TROUGH. THE LOW AND ASSOCIATED CONVECTION WITH THE FRONTAL
BOUNDARIES ARE SUPPORTED ALOFT BY AN UPPER LEVEL SHORTWAVE
TROUGH MOVING NE ACROSS NORTH TEXAS. MOIST SWLY FLOW...BRINGING
PACIFIC MOISTURE ACROSS MEXICO AND THE NORTHERN GULF IS ALSO
PROVIDING AN UPPER LEVEL DIFFLUENT ENVIRONMENT BETWEEN THE UPPER
LEVEL TROUGH AND A BROAD UPPER LEVEL ANTICYCLONIC CIRCULATION
CENTERED OVER THE WESTERN CARIBBEAN. THE REMAINDER OF THE GULF
REMAINS UNDER GENERALLY FAIR SKIES AND S-SE SURFACE WINDS UP TO
25 KT.

CARIBBEAN SEA...
AN UPPER LEVEL RIDGE IS CENTERED OVER THE WESTERN CARIBBEAN NEAR
17N78W WITH STRONG SUBSIDENCE AND DRY AIR NOTED ON WATER VAPOR
IMAGERY COVERING MUCH OF THE CARIBBEAN SEA AND CENTRAL AMERICA.
MOSTLY FAIR WEATHER CONTINUES ACROSS THE BASIN WITH MODERATE TO
STRONG EASTERLY TRADES EXPECTED TO PERSIST THROUGH EARLY
WEDNESDAY. HOWEVER...A FEW AREAS OF ISOLATED LOW-LEVEL SHOWERS
ARE OCCURRING ACROSS THE NW CARIBBEAN FROM 16N-21N BETWEEN
83W-88W AND OVER THE EASTERN CARIBBEAN E OF 72W.

ATLANTIC OCEAN...
A COLD FRONT ENTERS THE CENTRAL ATLC NEAR 32N47W AND EXTENDS SW
INTO THE SW NORTH ATLC ALONG 26N60W TO 25N70W WHERE IT CONTINUES
WESTWARD AS A STATIONARY FRONT TO DEERFIELD BEACH FLORIDA.
ISOLATED SHOWERS ARE WITHIN 60 NM EITHER SIDE OF THE COLD FRONT
AND WITHIN 90 NM NORTH OF THE STATIONARY FRONT. LINGERING
ISOLATED SHOWERS FOLLOW NW OF THE FRONT W OF 70W ACROSS THE
REMAINDER OF THE W ATLC AS A SURFACE RIDGE BUILDS IN N OF 26N W
OF 60W ANCHORED ON A 1037 MB HIGH CENTERED OVER SE VIRGINIA. THE
COLD FRONT IS SUPPORTED ALOFT BY AN UPPER LEVEL LONGWAVE TROUGH
LOCATED WELL NORTH OF THE AREA ACROSS THE NW NORTH ATLC. FARTHER
EAST...ACROSS THE REMAINDER OF THE CENTRAL ATLC AND EASTERN
ATLC...A BROAD SURFACE RIDGE IS IN PLACE ANCHORED BY A 1021 MB
HIGH CENTERED NEAR 25N38W BRINGING GENERALLY FAIR WEATHER E OF
50W.

$$
HUFFMAN





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