000 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