[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 021750
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
105 PM EST WED JAN 02 2008

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

...THE ITCZ...
THE ITCZ AXIS IS CENTERED ALONG 7N10W 3N16W 2N25W CROSSING THE
EQUATOR NEAR 37W INTO NE BRAZIL. WIDELY SCATTERED MODERATE
CONVECTION IS WITHIN 100 NM S OF THE AXIS EAST OF 15W...AND
WITHIN 125 NM N OF THE AXIS BETWEEN 30W-35W. A SFC TROUGH WAS
ANALYZED ON THE 1200 UTC SURFACE MAP FROM 7N26W TO EQUATOR AT
29W BASED ON SURFACE DATA AND AN EARLIER QUIKSCAT PASS. A RECENT
ASCAT PASS ALSO CONFIRMS THE PRESENCE OF THIS TROUGH. SCATTERED
MODERATE CONVECTION IS WITHIN 200 NM EAST TO THE NORTHERN END OF
THE TROUGH AXIS.

...DISCUSSION...
GULF OF MEXICO...
A COLD AIRMASS HAS BUILT INTO THE ENTIRE GULF BEHIND A STRONG
COLD FRONT EXTENDING FROM THE W ATLC WATERS ACROSS CENTRAL CUBA
INTO THE NW CARIBBEAN. VERY TIGHT PRESSURE GRADIENT BETWEEN THE
FRONT AND A 1046 MB HIGH OVER CENTRAL TEXAS IS PRODUCING NLY
GALE FORCE WINDS ACROSS MUCH OF THE SRN HALF OF THE REGION AS
NOTED IN BUOY/SHIP DATA AND RECENT ASCAT PASS. THESE STRONG
WINDS ARE CREATING DANGEROUS MARINE CONDITIONS. WINDS AND SEAS
WILL BEGIN TO SUBSIDE FROM W TO E ON THU AS THE STRONG HIGH
WEAKENS AND SHIFTS E. LOW TEMPERATURES ARE EXPECTED TO BE THE
COLDEST OF THE SEASON FOR MUCH OF FLORIDA ON THU. A WIND CHILL
ADVISORY IS ALREADY IN EFFECT FROM 9 PM THIS EVENING TO 9 AM EST
THURSDAY RIGHT HERE IN THE MIAMI AREA. A FREEZE WARNING HAS ALSO
BEEN ISSUED FOR THE SUNSHINE STATE. SATELLITE PHOTOS SHOW THAT
CONVECTIVE CLOUD STREETS ARE FORMING PARALLEL TO THE WIND ACROSS
THE GULF DUE TO THE ADVECTION OF COLD AIR OVER RELATIVELY WARM
WATERS. CLEARING IS BEGINNING TO OCCUR ACROSS THE N GULF WATERS.
MULTILAYERED CLOUDINESS AND EMBEDDED SHOWERS ARE SEEN OVER THE
BAY OF CAMPECHE ASSOCIATED WITH LOW-LEVEL CONVERGING FLOW AND A
DIFFLUENT PATTERN ALOFT. WARMER TEMPERATURES CAN BE EXPECTED BY
FRIDAY AND DURING THE UPCOMING WEEKEND AS HIGH PRES MOVES EWD
ACROSS THE W ATLC AND SOUTHERLY RETURN FLOW DEVELOPS ACROSS THE
AREA.

CARIBBEAN SEA...
A STRONG COLD FRONT IS MOVING ACROSS CENTRAL CUBA AND THE NW
CARIBBEAN. AS OF 1500 UTC...THE FRONT EXTENDS FROM THE PROVINCE
OF SANCTI-SPIRITUS IN CUBA TO SOUTHERN BELIZE INTO CENTRAL
GUATEMALA. VIS SATELLITE IMAGERY SHOWS A VERY WELL DEFINED BAND
OF CLOUDS WITH EMBEDDED SHOWERS ASSOCIATED WITH THE FRONT THAT
WILL MOVE TO THE WINDWARD PASSAGE TO HONDURAS TONIGHT AND FROM
THE MONA PASSAGE TO COSTA RICA THU NIGHT. NLY GALE FORCE WINDS
ARE BLOWING ACROSS THE YUCATAN CHANNEL AND THE FAR NW CARIBBEAN
AS SEEN IN SURFACE OBSERVATIONS. WINDS ARE EXPECTED TO DECREASE
BELOW GALE FORCE IN ABOUT 24 HOURS BUT SHOULD REMAIN STRONG THRU
THE END OF THE WEEK. THE REMAINDER OF THE BASIN IS PRETTY QUIET
UNDER THE INFLUENCE OF A VERY SUBSIDENT UPPER RIDGE CENTERED
JUST SE OF HISPANIOLA NEAR 16N68W. THIS WEATHER PATTERN IS
SUPPRESSING THE DEVELOPMENT OF ORGANIZED DEEP CONVECTION.
PATCHES OF LOW LEVEL MOISTURE WITH EMBEDDED SHOWERS ARE ENTERING
THE EASTERN CARIBBEAN THROUGH THE CENTRAL LESSER ANTILLES. ONE
OF THEM LEFT 1.17 INCHES OF RAIN IN GUADELOUPE IN THE LAST 24
HOURS.

ATLANTIC OCEAN...
THE LOW PRESSURE SYSTEM THAT THREATENED TO BECOME A NAMED
SUBTROPICAL STORM DAYS AGO CONTINUES TO WEAKEN OVER THE OPEN
OCEAN WATERS AS IT DRIFTS WWD. A SFC TROUGH EXTENDING N TO S
ALONG 47W IS ATTACHED TO THE LOW. A SWIRL OF LOW CLOUDS IS
ASSOCIATED WITH THIS FEATURE. WINDS HAVE DIMINISHED BELOW GALE
FORCE WITH AN EARLIER QUIKSCAT PASS SHOWING 20 TO 25 KT ON THE N
SEMICIRCLE. THIS LOW IS FORECAST TO DISSIPATE IN ABOUT 12-24
HOURS...LEAVING AN OPEN TROUGH IN THE AREA.

ANOTHER SIGNIFICANT FEATURE ACROSS THE FORECAST REGION IS THE
AFOREMENTIONED STRONG COLD FRONT THAT ENTERS THE AREA NEAR
31N68W THEN CONTINUES SW TO THE CENTRAL BAHAMAS/CUBA. SCATTERED
SHOWERS ARE POSSIBLE WITHIN 90 NM OF THE FRONT. NW WINDS
INCREASE SIGNIFICANTLY BEHIND THE BOUNDARY BUT EXPECTED TO BE
JUST BELOW GALE FORCE. MUCH COLDER AIR IS USHERING IN BEHIND THE
FRONT. THIS FRONTAL ZONE AND ITS UPPER TROUGH WILL ABSORB THE
ABOVE MENTIONED LOW PRES SYSTEM IN THE CENTRAL ATLC WITHIN THE
NEXT 24 HOURS OR SO. A 1029 MB HIGH LOCATED NEAR 32N38W
DOMINATES THE REMAINDER OF THE DISCUSSION AREA. STRONG SWLY
UPPER-LEVEL WINDS ASSOCIATED WITH A JETSTREAM BRANCH ARE
TRANSPORTING ABUNDANT UPPER LEVEL MOISTURE/HIGH CLOUDS FROM NE
BRAZIL ALL THE WAY NE TO THE COAST OF AFRICA NEAR 23N16W. THIS
JET WITH CORE WINDS OF 90 KT CROSS JUST N OF THE CAPE VERDE
ISLANDS.

$$
GR/JC



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