[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 281805
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
105 PM EST WED DEC 28 2005

TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL
AMERICA...GULF OF MEXICO...CARIBBEAN SEA...NORTHEASTERN 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1715 UTC.

...ITCZ...

ITCZ AXIS IS CENTERED ALONG 7N12W 5N32W 6N37W 2N50W.  ISOLATED
SHOWERS WITHIN 60 NM OF 1N10W AND WITHIN 60 NM OF 2N20W.  WIDELY
SCATTERED SHOWERS ARE S OF 4N W OF 40W.

...DISCUSSION...

GULF OF MEXICO...
COLD FRONT IS JUST ENTERING THE EXTREME NORTHWESTERN GULF WITH A
RETREATING RIDGE OF HIGH PRESSURE ORIENTED NE-SW OVER FLORIDA
FLORIDA AND THE EASTERN GULF.  SURFACE WIND IN THE GULF ARE
20-25 KT SOUTHWESTERLIES AHEAD OF THE FRONT.  BROKEN HIGH CLOUDS
ARE N OF 26N E OF 88W.  MOISTURE REMAINS LIMITED ALONG THE FRONT
AND IS SPARKING ONLY ISOLATED SHOWERS OVER THE NE GULF TODAY AND
INTO TOMORROW.  IN THE UPPER LEVELS...RELATED UPPER TROUGH IS
DIGGING INTO THE WESTERN GULF WITH ZONAL WESTERLY FLOW AND
STRONG SUBSIDENCE ELSEWHERE.  COLD FRONT WILL CONTINUE TO MOVE
ACROSS THE NW GULF AND WILL PASS THRU W FLORIDA TONIGHT AND
DIPPING INTO THEN THRU S FLORIDA ON THU.

CARIBBEAN SEA...
10-15 KT ELY SURFACE WINDS ARE OVER MOST OF THE CARIBBEAN...A
LITTLE HIGHER IN THE 15 TO 20 KT RANGE NW OF COLOMBIA.
CONVERGENCE ON THE TAIL END OF A DISSIPATED FRONT...NOW A WEAK
SURFACE TROUGH...IS PRODUCING BROKEN/OVERCAST CLOUDINESS AND
ISOLATED SHOWERS/TSTMS WITHIN 75 NM OF LINE 12N83W 18N82W.
PATCHY LOW CLOUDS ARE IN THE E CARIBBEAN WITH ISOLATED SHOWERS.
LOW-LEVEL DRY AIR CONTINUES TO LIMIT THESE SHOWERS WITH
DEWPOINTS NEAR OR BELOW 70F FROM HISPANIOLA EASTWARD THRU PUERTO
RICO AND THE LEEWARD ISLANDS.  UPPER RIDGING OVER NORTHERN S
AMERICA DOMINATES THE REGION WITH GENERALLY ANTICYCLONIC FLOW
ALOFT E OF 80W AS SEEN IN CIMSS IMAGERY.  NO BIG CHANGES ARE
EXPECTED THOUGH THE W CARIBBEAN SHOULD DRY OUT A LITTLE AS ANY
MOISTURE GETS PUSHED INTO CENTRAL AMERICA BY FRI.

ATLANTIC OCEAN...
COLD FRONT OVER THE W ATLC EXTENDS FROM 32N51W THROUGH
HISPANIOLA NEAR 19N73W.  WIDELY SCATTERED TSTMS ARE WITHIN 60 NM
OF THE FRONT N OF 26N DUE TO AN UPPER SHORTWAVE NEAR 34N53W THAT
IS ENHANCING UPPER LIFT.  ONLY ISOLATED SHOWERS ARE N OF 22N AND
COLD AIR STRATOCUMULUS ARE BEHIND THE FRONT TO 72W.  LARGE BUT
WEAKENING UPPER TROUGH OVER THE W ATLC IS PROVIDING THE PUSH FOR
THE FRONT.  1032 MB HIGH IS N OF THE AREA OVER THE AZORES WITH
STRONGER TRADES IN THE E ATLC E OF 50W.  THE TROPICAL ATLC
CONTINUES TO BE RATHER QUIET W OF 35W AS MODERATE/STRONG
SUBSIDENCE DOMINATES.  HOWEVER AN UPPER LOW NEAR 19N37W IS
PRODUCING A LARGE AREA OF CLOUDS E OF 36W WITH A WEAK SURFACE
TROUGH REFLECTION FROM 8N35W 16N35W.  OVERCAST HIGH CLOUDS WITH
EMBEDDED POCKETS OF SHOWERS/TSTMS ARE E OF 36W TO W AFRICA
BETWEEN 14N-23N WITH THE DEEPEST CONVECTION WITHIN 120 NM OF
20N31W.  MODELS INDICATE THIS AREA OF DISTURBED WEATHER SHOULD
CONTINUE OVER THE REGION AND DRIFT WESTWARD WITH THE UPPER LOW.
UPPER RIDGING COVERS THE CENTRAL ATLC BETWEEN THE UPPER
TROUGH/LOW AND E OF THE UPPER LOW.  WEAK COLD FRONT IS IN THE
FAR NE PART OF THE REGION GRAZING THE COAST OF MOROCCO.

$$
LANDSEA


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