000 AXNT20 KNHC 041744 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 105 PM EST TUE DEC 04 2007 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... ITCZ IS CENTERED ALONG 5N9W 4N20W 4N35W 3N45W AND INTO SOUTH AMERICA NEAR 1S51W. CLUSTERS OF MODERATE TO STRONG CONVECTION ARE ALONG THE SW COAST OF AFRICA BETWEEN THE PRIME MERIDIAN AND 10W. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS WITHIN 60 NM EITHER SIDE OF THE AXIS BETWEEN 22W-31W. SIMILAR CONVECTION IS FOUND N OF AXIS FROM 6N-10N BETWEEN 35W-38W. DISCUSSION... THE GULF OF MEXICO... AS OF 1500 UTC...A COLD FRONT ENTERS THE AREA THROUGH THE STRAITS OF FLORIDA...JUST SOUTH OF THE FLORIDA KEYS TO VERACRUZ MEXICO ALONG 23N90W 18N96W. A THIN BAND OF SCATTERED SHOWERS AND ISOLATED TSTMS IS WITHIN 60 NM OF THE FRONT. THIS FEATURE IS EXPECTED TO STALL OVER THE FLORIDA STRAITS TONIGHT AND GRADUALLY DISSIPATE THROUGH WED. A QUIKSCAT PASS FROM AROUND 1200 UTC SHOWED MODERATE TO STRONG WINDS OF 20-25 KT BEHIND THE FRONT OVER THE SW PORTION OF THE GULF. THE REMAINDER OF THE AREA IS EXPERIENCING LIGHT TO MODERATE WINDS AND FAIR WEATHER DUE TO BUILDING HIGH PRESSURE BEHIND THE FRONT. A 1024 MB SFC HIGH IS ANALYZED OVER THE DEEP SOUTH. ALOFT...AN UPPER-LEVEL TROUGH EXTENDS MAINLY EAST TO WEST ACROSS THE CENTRAL GULF SUPPORTING THE COLD FRONT. WV IMAGERY REVEALS STRONG SUBSIDENCE AND VERY DRY AIR BEHIND THE TROUGH AXIS. THE CARIBBEAN SEA... WEAK SURFACE PRES GRADIENT DOMINATES THE AREA DUE TO THE PRESENCE OF A COLD FRONT ACROSS THE STRAITS OF FLORIDA/GULF OF MEXICO AND A COUPLE OF TROUGHS OVER THE TROPICAL N ATLANTIC. THIS PATTERN IS PROVIDING LIGHT N TO NE WINDS ACROSS THE CARIBBEAN. AN AREA OF SCATTERED SHOWERS IS OVER THE SW CARIBBEAN ENHANCED BY UPPER DIFFLUENCE. ALOFT...WLY FLOW DOMINATES THE BASIN N OF 16N...INCLUDING THE GREATER ANTILLES WITH A RIDGE COVERING NORTHERN SOUTH AMERICA... CENTRAL AMERICA AND THE REMAINDER OF THE CARIBBEAN SEA. TYPICAL PATCHES OF LOW LEVEL MOISTURE ARE SEEN PARTICULARLY AROUND THE CAYMAN ISLANDS AND JUST SOUTH OF PUERTO RICO. THE ATLANTIC OCEAN... A COLD FRONT ENTERS THE REGION NEAR 31N67W THEN CONTINUES SW ACROSS THE W ATLC CROSSING THE BAHAMAS JUST NORTH OF NASSAU INTO THE STRAITS OF FLORIDA AND THE GULF OF MEXICO. A BAND OF SHOWERS AND ISOLATED THUNDERSTORMS IS WITHIN 60 NM OF THE FRONT. AN EARLIER QUIKSCAT PASS SHOWED SW WINDS OF 20 TO 25 KT AHEAD OF THE FRONT N OF 26N W OF 60W. ANOTHER COLD FRONT EXTENDS FROM 31N33W TO 23N48W. CLOSE TO THE TAIL END OF THIS FRONTAL SYSTEM...A WEAK 1012 MB SFC LOW PERSISTS. IT IS CENTERED NEAR 22.5N51W. A TROUGH RUNS FROM THE LOW TO THE LEEWARD ISLANDS...WHERE IS PRODUCING SOME CLOUDINESS AND LIGHT SHOWERS. VIS SATELLITE IMAGERY SHOWS VERY WELL THE CYCLONIC CIRCULATION ASSOCIATED WITH THIS LOW THAT IS GENERATING ISOLATED TO SCATTERED SHOWERS. A 1020 MB HIGH IS CENTERED NEAR 31N43N PRODUCING FAIR WEATHER STRATOCUMULUS OVER THE CENTRAL ATLC. THE SURFACE HIGH IS EXPECTED TO MOVE RAPIDLY TO THE NE OVER THE NEXT 24 HOURS. IN THE TROPICAL ATLC...A WEAK SURFACE TROUGH IS ALONG 58W FROM 10N-17N. A RIDGE DOMINATES THE E ATLC ANCHORED ON A HIGH LOCATED NE OF THE MADEIRA ISLANDS. THIS HIGH WILL MOVE SW APPROACHING TO THE FORECAST AREA. ALOFT... MOISTURE/HIGH CLOUDS ARE BEING TRANSPORTED EASTWARD AROUND A BROAD E-W UPPER RIDGE COVERING THE TROPICAL ATLC S OF 21N. A TROUGH/RIDGE/TROUGH PATTERN IS OVER THE REMAINDER OF THE REGION. $$ GR