000 AXNT20 KNHC 132352 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 705 PM EST TUE JAN 13 2009 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 1715 UTC. ...THE ITCZ... THE ITCZ IS CENTERED ALONG 7N12W 4N20W 2N30W 3N40W...CROSSING THE EQUATOR ALONG 45W...INTO NORTHEASTERN BRAZIL NEAR 1S48W. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS WITHIN 90 NM SOUTH OF AXIS BETWEEN 22W-27W...AND WITHIN 100 NM N OF AXIS BETWEEN 27W-33W. SCATTERED MODERATE CONVECTION IS NEAR 5N15W. ...DISCUSSION... THE GULF OF MEXICO... AS OF 2100 UTC...A COLD FRONT EXTENDS FROM CENTRAL FLORIDA TO THE YUCATAN PENINSULA ALONG 28N81W 23N86W 19N90W. A WELL DEFINED BAND OF MULTILAYERED CLOUDS WITH EMBEDDED SHOWERS AND ISOLATED TSTMS...SOME WITH HEAVIER RAIN AND GUSTY WINDS...IS ASSOCIATED WITH THE FRONT. MOSAIC DOPPLER RADAR FROM THE SE U.S. REVEALS THAT THE STRONGEST CONVECTIVE ACTIVITY IS CURRENTLY OVER CENTRAL FLORIDA. SCATTERED SHOWERS AND ISOLATED TSTMS ARE ALSO AFFECTING THE FLORIDA KEYS. THIS FRONT WAS REINFORCED THIS AFTERNOON BY A DRY COLD FRONT SWEEPING QUICKLY INTO THE CENTRAL AND SE GULF. THESE MERGED FRONTS WILL CONTINUE TO MOVE QUICKLY INTO THE EXTREME SE GULF AND THE NW CARIBBEAN THIS EVENING...FOLLOWED BY STRONG NORTHERLY FLOW...WITH GALE FORCE WINDS BRIEFLY TO OCCUR ACROSS THE FAR SW BAY OF CAMPECHE. ADDITIONALLY...STRONG N TO NE SURFACE WINDS ARE BLOWING THROUGH THE ISTHMUS OF TEHUANTEPEC RESULTING IN GALE FORCE WINDS IN THE E PACIFIC REGION. TEMPERATURES ARE IN THE 40'S AND 50'S OVER THE N GULF STATES UNDER CLEAR SKIES WHILE TEMPERATURES S OF THE COLD FRONT REMAIN IN THE 70'S. IN THE UPPER LEVELS...A BROAD MID/UPPER LEVEL TROUGH WHICH SUPPORTS THE AFOREMENTIONED COLD FRONT EXTENDS FROM THE GREAT LAKES REGION TO LOUISIANA CLIPPING THE NW CORNER OF THE GULF INTO NORTHERN MEXICO. SOUTHWESTERLY WINDS AHEAD OF THE TROUGH ARE ADVECTING ABUNDANT MID TO UPPER LEVEL MOISTURE FROM THE EPAC ACROSS SOUTH-CENTRAL MEXICO AND THE YUCATAN PENINSULA INTO THE GULF OF MEXICO AND THE FLORIDA PENINSULA. MID/UPPER LEVEL SUBSIDENCE AND ASSOCIATED DRY AIR IS OVER THE REMAINDER OF THE GULF WATERS. THE CARIBBEAN SEA... A TIGHT SURFACE PRESSURE GRADIENT BETWEEN HIGH PRES N OF AREA AND THE SEMI-PERMANENT SFC LOW OVER COLOMBIA/PANAMA IS STILL PRODUCING MODERATE TO STRONG TRADEWINDS ACROSS THE BASIN. AS USUAL...THE STRONGEST WINDS ARE NEAR THE COAST OF COLOMBIA WHERE AN EARLIER QSCAT PASS SHOWED ELY WINDS OF 20 TO 30 KT. CLOUDS ARE ON INCREASE ACROSS THE NW CARIBBEAN AHEAD OF THE COLD FRONT CURRENTLY MOVING OVER THE SE GULF OF MEXICO. THIS FRONT IS FORECAST TO ENTER THE NW CARIBBEAN EARLY WEDNESDAY. UPPER DIFFLUENCE BETWEEN A RIDGE OVER THE CARIBBEAN...WITH AXIS FROM WESTERN VENEZUELA TO HISPANIOLA AND THE ABOVE MENTIONED BROAD MID/UPPER LEVEL TROUGH IS HELPING TO INDUCE SOME CLOUDINESS OVER THE WESTERN CARIBBEAN AND CUBA. MODERATE TO STRONG UPPER-LEVEL SUBSIDENCE AND IMPLIED DRY AIR MASS DOMINATES THE E CARIBBEAN AND VENEZUELA COURTESY OF THIS RIDGE. THE ATLANTIC OCEAN... A COLD FRONT ENTERS THE FORECAST AREA NEAR 31N77W THEN CONTINUES SW CROSSING CENTRAL FLORIDA AND THE SE GULF OF MEXICO INTO THE YUCATAN PENINSULA. SCATTERED SHOWERS AND ISOLATED TSTMS ARE ASSOCIATED WITH THE FRONTAL BOUNDARY. MAINLY HIGH CLOUDS ARE NOTED OVER THE BAHAMAS. JUST AHEAD OF THE FRONT...SW TO S WINDS OF 20 TO 30 KT PREVAIL WHILE NW WINDS OF 15 TO 20 KT ARE SEEN BEHIND THE FRONT. THE REMAINDER OF THE FORECAST REGION REMAINS UNDER THE INFLUENCE OF A SFC RIDGE ANCHORED BY A 1029 MB HIGH SITUATED NEAR 34N23W. ANOTHER 1027 MB SFC HIGH IS NEAR 28N54W. MOSTLY FAIR WEATHER IS NOTED N OF 20N BETWEEN 30W-65W. ALOFT...A RIDGE/TROUGH/RIDGE PATTERN DOMINATES THE AREA. THE UPPER-LEVEL TROUGH STRETCHES ACROSS THE CENTRAL ATLC INTO THE DEEP TROPICS WITH THE BASE OF THIS TROUGH ALMOST REACHING THE COAST OF NORTHERN SOUTH AMERICA. UPPER DIFFLUENCE BETWEEN THIS TROUGH AND AN UPPER-LEVEL RIDGE OVER THE E ATLC IS HELPING TO INDUCE A LARGE AREA OF CLOUDINESS WITH EMBEDDED SHOWERS WHICH IS AFFECTING MUCH OF THE TROPICS PARTICULARLY BETWEEN THE CAPE VERDE ISLANDS AND 45W. THE GFS MODEL SUGGESTS THAT THIS AREA OF MOISTURE WILL MOVE EWD UNDER THE TRADE WIND FLOW AFFECTING THE LESSER ANTILLES AND THEN THE US/UK VIRGIN ISLANDS AND PUERTO RICO LATE THURSDAY INTO FRIDAY. $$ GR