000 AXNT20 KNHC 091750 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 105 PM EST MON FEB 09 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 1715 UTC. ...THE ITCZ... ITCZ IS CENTERED ALONG 5N9W 1N20W 1N40W CROSSING THE EQUATOR AT 47W...AND INTO NE BRAZIL NEAR 1S50W. A CLUSTER OF MODERATE TO ISOLATED STRONG CONVECTION IS FROM 3N TO THE COAST OF AFRICA BETWEEN 3W-8W. SCATTERED MODERATE CONVECTION IS WITHIN 60N S OF AXIS BETWEEN 13W-17W...AND FROM 2S TO THE EQUATOR BETWEEN 30W AND 36W. ...DISCUSSION... GULF OF MEXICO... THE WEATHER PATTERN HAS NOT EXPERIENCED MUCH CHANGE ACROSS THE GULF REGION SINCE YESTERDAY. THE AREA CONTINUES UNDER THE INFLUENCE OF A 1029 MB SFC HIGH CENTERED NEAR 29N80W AT 1500 UTC. THE RIDGE AXIS EXTENDS SW INTO THE BAY OF CAMPECHE AND SE MEXICO INCLUDING THE YUCATAN PENINSULA. THIS SYSTEM IS PRODUCING MOSTLY FAIR WEATHER AND SE-S RETURN FLOW WITH SPEEDS OF 20-25 KT OVER MUCH OF THE GULF WATERS. THESE WINDS ARE EXPECTED TO DIMINISH LATE TODAY AS THE SFC HIGH MOVES AWAY FROM THE FORECAST AREA...AND THE PRES GRADIENT RELAXES. ALOFT...A MID/UPPER LEVEL RIDGE DOMINATES THE ENTIRE GULF AND THE SE CONUS. THE NEXT COLD FRONT IS FORECAST TO MOVE OFF TEXAS COAST EARLY WED. THE RETURN FLOW WILL INCREASE AGAIN TO 20-25 KT LATER ON TUE IN ADVANCE OF THE FRONT. CARIBBEAN SEA... A SFC TROUGH...REMNANTS OF AN OLD FRONTAL BOUNDARY...IS ANALYZED ACROSS THE MONA PASSAGE ON THE 1200 UTC SFC MAP. A LARGE AREA OF MOISTURE WITH SOME INVERTED-V CLOUD PATTERN AND EMBEDDED MODERATE SHOWERS ARE ASSOCIATED WITH THE TROUGH. THIS ACTIVITY IS AFFECTING THE UK/US VIRGIN ISLANDS...PUERTO RICO AND DOMINICAN REPUBLIC WHICH HAS REPORTED SIGNIFICANT RAINFALL AMOUNTS OF AROUND 2 INCHES IN SEVERAL PLACES FOR THE PAST 24 AND 48 HOURS. THE GFS COMPUTER MODEL HAS MOISTURE FROM THIS TROUGH MOVING WWD ACROSS HISPANIOLA AND THE CARIBBEAN REGIONAL WATERS DURING THE NEXT 24 HOURS OR SO WHICH MEANS A RISK OF ADDITIONAL POTENTIALLY HEAVY RAINFALL OVER DOMINICAN REPUBLIC. DURING THE 24 HOURS...A TOTAL OF 1.06 INCHES OF RAIN FELL IN SAN JUAN...WHILE 1.55 INCHES OF RAIN FELL IN ST THOMAS. POCKETS OF MOISTURE WITH MAINLY LIGHT RAIN ARE ALSO AFFECTING MUCH OF CENTRAL AMERICA. A TIGHT SURFACE GRADIENT BETWEEN THE SURFACE HIGH N OF AREA AND LOWER PRES OVER S AMERICA IS PRODUCING FRESH TO STRONG TRADE WINDS OVER THE CENTRAL AND W CARIBBEAN. AN EARLIER QSCAT PASS SHOWED NE WINDS OF UP TO 30 KT JUST OFFSHORE THE COAST OF COLOMBIA. THESE WINDS ARE EXPECTED TO DIMINISH SLIGHTLY ON TUE...BUT WILL INCREASE AGAIN LATER ON TUE AND INTO FRI AS NEW ATLC HIGH PRES BUILDS OVER THE SW N ATLC. ALOFT...A SHORT-WAVE TROUGH IS OVER THE CENTRAL BAHAMAS AND CUBA EXTENDING INTO THE CARIBBEAN SEA TO NEAR CABO GRACIAS A DIOS NICARAGUA. AN UPPER-LEVEL HIGH CENTERED OVER NE BRAZIL EXTENDS A RIDGE NW ENVELOPING THE EASTERN CARIBBEAN. SWLY FLOW BETWEEN THESE TWO UPPER-LEVEL FEATURES IS ADVECTING SOME MID/UPPER LEVEL MOISTURE FROM COLOMBIA INTO THE CARIBBEAN SEA. ATLANTIC OCEAN... THE MAIN FEATURE ACROSS THE FORECAST AREA IS A SFC TROUGH... REMNANTS OF AN OLD FRONTAL BOUNDARY...THAT ENTERS THE REGION NEAR 31N30W THEN CONTINUES SW ALONG 25N45W 20N66W INTO THE MONA PASSAGE. SEE THE CARIBBEAN SEA SECTION FOR MORE DETAILS. A PRETTY WELL DEFINED NARROW BAND OF CLOUDS IS RELATED TO THE TROUGH ACROSS THE ATLC OCEAN. A WEAK SFC TROUGH IS ALSO ANALYZED ALONG 57W SOUTH OF 12N TO THE COAST OF SURINAME. UPPER-LEVEL DIFFLUENCE ASSOCIATED WITH THE ABOVE MENTIONED RIDGE OVER N SOUTH AMERICA IS HELPING TO INDUCE SOME SHOWER ACTIVITY EITHER SIDE OF THE TROUGH. A 1029 MB SFC HIGH IS CENTERED JUST E OF NE FL NEAR 29N80W. THIS SYSTEM WILL MERGE WITH A STRONGER HIGH PRES EXITING THE MID ATLC STATES. THIS WILL MAINTAIN A TIGHT PRES GRADIENT OVER THE BAHAMAS...THE GREATER ANTILLES AND THE CARIBBEAN SEA INCLUDING THE PASSAGES THROUGH EARLY WED. A COUPLE OF 1025 MB SFC HIGHS ARE OVER THE REMAINDER OF THE DISCUSSION AREA. ONE IS NEAR 35N37W WHILE THE SECOND IS EAST OF THE MADEIRA ISLANDS NEAR 33N12W. ALOFT...A TROUGH/RIDGE/TROUGH PATTERN DOMINATES THE AREA. $$ GR