[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 192339
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
705 PM EST SUN DEC 19 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
2330 UTC.

...ITCZ...

THE ITCZ AXIS IS ANALYZED FROM THE COAST OF GUINEA NEAR 10N14W
CONTINUING WEST ALONG 7N20W 8N30W 6N37W 11N50W. SCATTERED
MODERATE TO ISOLATED STRONG CONVECTION IS FROM THE EQUATOR TO
12N BETWEEN 30W AND 44W. SCATTERED MODERATE TO STRONG CONVECTION
IS WITHIN 90 NM ON EITHER SIDE OF THE ITCZ BETWEEN 18W AND 30W.
A SURFACE TROUGH IS EMBEDDED IN THE ITCZ EXTENDING FROM 13N51W
TO A WEAK 1006 MB LOW NEAR 10N52W CONTINUING S TO 7N51W.
SCATTERED MODERATE TO STRONG CONVECTION IS FROM 10N TO 13N
BETWEEN 48W AND 53W.

...DISCUSSION...

GULF OF MEXICO...
THE COLD FRONT THAT WAS IMPACTING THE GULF FROM A FEW DAYS AGO
HAS NOW MOVED OUT OF THE DISCUSSION AREA INTO THE WEST ATLC AND
NW CARIBBEAN. IN RESPONSE...A COLD AIRMASS IS IN PLACE ACROSS
THE GULF. LOW LEVEL STRATOCUMULUS CLOUDS ARE CONCENTRATED OVER
THE EASTERN HALF OF THE BASIN E OF 90W...EMBEDDED IN THE NNW
FLOW. A MORE PRONOUNCED CLEARING AND NNE FLOW IS OBSERVED W OF
90W. LAST SATELLITE IMAGES OF THE DAY INDICATED LOW LEVEL
OVERCAST CONDITIONS OVER THE FAR NE BASIN N OF 27N E OF
84W...INCLUDING THE FLORIDA PENINSULA. A WEAK SURFACE TROUGH IS
WHITING 65 NM ALONG THE COAST OF MEXICO FROM N OF TAMPICO NEAR
23N96W TO SE OF VERACRUZ 19N95W GENERATING SCATTERED SHOWERS
WITHIN 20 NM OF THE AXIS. LOOK FOR ANTICYCLONIC FLOW TO DEVELOP
ACROSS THE GULF AS AN UPPER LEVEL RIDGE OF HIGH PRESSURE SETTLES
OVER THE REGION OVER THE NEXT 24 HOURS.

CARIBBEAN SEA...
THE BASE OF AN UPPER LEVEL TROUGH/LONGWAVE SWINGS BY THE NW
CARIBBEAN...NOTED BY STRONG SUBSIDENCE AND DRY AIR ALOFT ON
WATER VAPOR IMAGERY N OF 11N W OF 72W. THIS UPPER FEATURE
SUPPORTS A DISSIPATING COLD FRONT EXTENDING FROM EASTERN CUBA
NEAR 20N75W WESTWARD TO THE YUCATAN PENINSULA NEAR 19N87W. THE
CONVECTION WITH THIS SYSTEM IS VERY LIMITED DUE TO THE DRY UPPER
LEVEL ENVIRONMENT PRODUCED BY THE LONGWAVE. THE SAME UPPER LEVEL
FEATURE SUPPORTS A SURFACE TROUGH THAT ENTERS THE NORTHERN
CARIBBEAN ACROSS HISPANIOLA NEAR 19N70W TO THE CENTRAL BASIN
NEAR 14N71W. SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS ARE
WITHIN 70 NM ON EITHER SIDE OF THE AXIS. THE REMAINDER OF THE
CARIBBEAN IS DOMINATED BY AN UPPER RIDGE ANCHORED NEAR THE ABC
ISLANDS. 15-20 KT TRADE WINDS ARE OVER THE EASTERN BASIN E OF
67W WITH ISOLATED SHOWERS EMBEDDED IN THE FLOW. EXPECT THE
SURFACE TROUGH TO MOVE EASTWARD SUPPORTING SHOWER ACTIVITY OVER
THE NE CARIBBEAN OVER THE NEXT 24 HOURS.

ATLANTIC OCEAN...
THE UPPER LEVEL LONGWAVE/TROUGH IS MOVING OFF THE EASTERN CONUS
SEABOARD SUPPORTING A FAST MOVING LOW PRESSURE SYSTEM AROUND
28N69W AND ASSOCIATED COLD FRONT EXTENDING WSW TO THE NORTHERN
CARIBBEAN ALONG 24N71W 20N75W. A PRE-FRONTAL TROUGH EXTENDS ESE
FROM THE LOW CENTER TO HISPANIOLA ALONG 25N67W 19N70W. WHILE THE
COLD FRONT LACKS OF CONVECTION DUE TO THE DRY UPPER LEVEL
ENVIRONMENT PRODUCED BY THE LONGWAVE...SCATTERED SHOWERS AND
ISOLATED THUNDERSTORMS ARE WITHIN 70 NM ON EITHER SIDE OF THE
TROUGH AXIS. HOWEVER...WIDESPREAD SHOWERS AND THUNDERSTORMS ARE
ACROSS MUCH OF THE WESTERN ATLC N OF 25N BETWEEN 60W AND 72W.
THIS AREA OF CONVECTION/TROUGHINESS IS UNDER STRONG DIFFLUENCE
ALOFT BETWEEN THE UPPER TROUGH ACROSS THE EASTERN CONUS AND AN
UPPER LEVEL RIDGE ACROSS THE CENTRAL ATLC. THIS UPPER LEVEL
RIDGE IS SUPPORTING SURFACE RIDGING ACROSS THE REMAINDER OF THE
CENTRAL ATLC ANCHORED BY A 1016 MB HIGH NEAR 25N51W PROVIDING
MOSTLY FAIR WEATHER CONDITIONS BETWEEN 40W AND 60W. A COLD FRONT
ENTERS THE EASTERN ATLC NEAR 32N20W CONTINUING SW ALONG 25N25W
21N33W BECOMING STATIONARY TO 18N46W. ISOLATED SHOWERS ARE
WITHIN 100 NM AHEAD OF THE FRONT N OF 25N. SIMILAR ACTIVITY IS
WITHIN 60 NM ON EITHER SIDE OF THE STATIONARY FRONT. THE SYSTEM
IS SUPPORTED BY AN UPPER LEVEL LOW/TROUGH CENTERED AROUND 34N20W.

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

$$

GARCIA



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