[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 251139
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
705 AM EST SAT DEC 25 2010

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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1130 UTC.

...THE ITCZ...

ITCZ AXIS IS ANALYZED FROM THE COAST OF LIBERIA NEAR 7N11W
WESTWARD ALONG 3N20W 3N30W 4N40W TO THE COAST OF BRAZIL NEAR
2N50W. SCATTERED MODERATE CONVECTION IS WITHIN 30 NM ON EITHER
SIDE OF THE AXIS BETWEEN 11W AND 43W.

...DISCUSSION...

GULF OF MEXICO...
A STRONG UPPER LEVEL SHORTWAVE QUICKLY MOVES ACROSS THE NW GULF
SUPPORTING A 1014 MB LOW OFF THE COAST OF LOUISIANA NEAR 30N92W.
A COLD FRONT EXTENDS SW FROM THE LOW CENTER TO VERACRUZ MEXICO.
A PRE-FRONTAL SURFACE TROUGH IS STARTING TO DEVELOP SOUTH OF THE
LOW CENTER NEAR 28N91W EXTENDING S TO NEAR 23N92W. MOSAIC
DOPPLER RADAR IMAGERY INDICATED A LINE OF HEAVY SHOWERS AND
THUNDERSTORMS N OF 23N WITHIN 40 NM EAST OF THE FRONT AND
PRE-FRONTAL TROUGH. STRONG SUBSIDENCE ALOFT IS NOTED BEHIND THE
FRONT ON WATER VAPOR IMAGERY. THIS SYSTEM WILL CONTINUE TO TRACK
EASTWARD ACROSS THE NORTHERN GULF WITH MODERATE TO STRONG
CONVECTION AFFECTING THE COASTAL WATERS OF LOUISIANA...
MISSISSIPPI...ALABAMA...AND THE FLORIDA PANHANDLE OVER THE NEXT
18 HOURS. FAIR WEATHER CONDITIONS ARE ELSEWHERE AT THE MOMENT.

CARIBBEAN SEA...
DRY AIR AND SUBSIDENCE ALOFT IS NOTED ON WATER VAPOR IMAGERY
OVER THE NW CARIBBEAN WITH MOSTLY ZONAL FLOW ALOFT ACROSS THIS
AREA. HOWEVER...THE FLOW TURNS MORE SOUTHWESTERLY ELSEWHERE
ACROSS THE REGION...AROUND AN UPPER LEVEL HIGH CENTERED OVER THE
EASTERN TROPICAL ATLC. THIS IS BRINGING DEEP MOISTURE FROM
NORTHERN SOUTH AMERICA TO MUCH OF THE SOUTHERN HALF OF THE
CARIBBEAN...AS WELL AS ENHANCING CONVECTION FOCUSED ALONG A
SHEAR AXIS EXTENDING ACROSS THE SOUTHERN CARIBBEAN ALONG 14N61W
13N70W 10N80W. NNE FLOW N OF THE BOUNDARY AND TRADE WINDS S OF
THE BOUNDARY ARE CONVERGING ALONG THE AXIS TO GENERATE SCATTERED
SHOWERS AND ISOLATED THUNDERSTORMS WITHIN 60 NM EITHER SIDE OF
THE LINE. COMPUTER MODELS SUGGEST THE CONVECTION WILL LINGER
OVER THE AREA FOR THE NEXT FEW DAYS. SCATTERED SHOWERS ARE ALSO
OVER PUERTO RICO AND HISPANIOLA N OF 16N BETWEEN 65W AND 75W DUE
TO A WEAKENING COLD FRONT MAKING ITS WAY IN FORM THE ATLC. THESE
SHOWERS ARE EXPECTED TO LINGER OVER THE NEXT 24 HOURS AS THE
COLD FRONT LOOSES MOMENTUM AND BECOMES NEAR STATIONARY IN THIS
REGION.

ATLANTIC OCEAN...
AN UPPER RIDGE THAT COVERS THE FAR W ATLC W OF 60W PROVIDING
RELATIVELY FAIR WEATHER CONDITIONS ACROSS THE AREA. HOWEVER...A
LARGE AND BROAD DEEP LAYER TROUGH IS OVER THE NORTH CENTRAL ATLC
BY A 966 MB LOW CENTERED E OF NEWFOUNDLAND NEAR 48N47W THAT
CONTINUES TO EXTEND INFLUENCE OVER MUCH OF THE CENTRAL ATLC.
THIS SYSTEM SUPPORTS A COLD FRONT THAT ENTERS THE DISCUSSION
AREA NEAR 32N39W AND EXTENDS SW ALONG 24N50W TO THE DOMINICAN
REPUBLIC NEAR 18N69W. ISOLATED SHOWERS ARE WITHIN 30 NM E OF THE
FRONT WITH DENSE LOW LEVEL CLOUDS AND POSSIBLE ISOLATED SHOWERS
WITHIN 60 NM W OF THE FRONT WITH WINDS UP TO 30 KT. COLD AIR
STRATOCUMULUS CLOUDS COVER THE REMAINDER OF THE ATLC W OF THE
FRONT. TO THE SW OF THIS FRONT INTO THE WEST TROPICAL ATLC...A
PRE-FRONTAL TROUGH IS ANALYZED FROM 23N47W TO 18N53W TO 12N56W
SUPPORTING ISOLATED SHOWERS AND THUNDERSTORMS WITHIN 60 NM EAST
OF THE AXIS N OF 18N. A SHEAR AXIS IS WEST OF THE SURFACE TROUGH
FROM 15N57W WSW INTO THE CARIBBEAN SEA WITH SCATTERED SHOWERS
AND ISOLATED THUNDERSTORMS WITHIN 30 NM EITHER SIDE OF THE LINE.
THE REMAINDER OF THE EASTERN ATLC IS UNDER THE INFLUENCE OF A
SURFACE RIDGE ANCHORED BY A 1020 MB HIGH CENTERED NEAR 28N23W.

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

$$

GARCIA




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