000 AXNT20 KNHC 152344 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 805 PM EDT SUN MAR 15 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 2315 UTC. ...ITCZ... THE ITCZ AXIS IS CENTERED ALONG 5N10W 2N20W CROSSING THE EQUATOR NEAR 29W EXTENDING TO 3S35W AND INTO NE BRAZIL NEAR 5S40W. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS S OF 3N BETWEEN 8W-17W. ISOLATED MODERATE CONVECTION IS S OF 2N BETWEEN 30W-36W. ...DISCUSSION... GULF OF MEXICO... A SLOWLY PROGRESSING COLD FRONT EXTENDS INTO THE N/CENTRAL GULF FROM A WEAK 1017 MB SFC LOW CENTERED OVER WESTERN GEORGIA TO NEAR 28N89W. AT THIS POINT...THE FRONT BECOMES STATIONARY AND STRETCHES ALONG 27N92W 23N99W INTO THE CENTRAL SECTION OF THE BAY OF CAMPECHE NEAR 19N94W. IT CONTINUES INLAND ALONG THE ERN SLOPE OF THE SIERRA MADRE ORIENTAL MOUNTAINS. THE FRONT IS LOCATED AT THE LEADING EDGE OF A WIDE BAND OF MULTILAYERED CLOUDS WITH EMBEDDED AREAS OF RAIN AND POSSIBLE ISOLATED TSTMS. LOW LEVEL CONVERGENCE AND DEEP LAYERED ATMOSPHERIC LIFT ARE SUPPORTING THIS ACTIVITY WHICH IS AFFECTING MAINLY THE FAR WESTERN GULF AND THE N GULF STATES BETWEEN GEORGIA AND EASTERN TEXAS INCLUDING ALSO THE FLORIDA PANHANDLE. N-NE SURFACE WINDS OF 10 TO 15 KT ARE OBSERVED BEHIND THE FRONT. TO THE SE OF THE FRONT...MODERATE SUBSIDENCE IS RESULTING IN GENERALLY FAIR WEATHER CONDITIONS ACROSS MUCH OF THE S-CENTRAL AND ERN GULF... INCLUDING THE FLORIDA PENINSULA. MODERATE SE WINDS ARE BLOWING AHEAD OF THE FRONT. AN UPPER-LEVEL TROUGH EXTENDING OVER WESTERN TEXAS AND NW MEXICO IS PRODUCING STRONG SWLY WINDS ALOFT OVER MUCH OF THE GULF REGION. THESE WINDS ARE ADVECTING CONSIDERABLE MID/UPPER LEVEL MOISTURE N OF LINE BETWEEN TAMPA BAY FLORIDA AND TAMPICO MEXICO. ACCORDING TO THE GFS COMPUTER MODEL...THE FRONT WILL CONTINUE TO SLOWLY MOVE SE APPROACHING SOUTH FLORIDA LATE ON TUESDAY. CARIBBEAN SEA... THE COMBINATION OF STRONG HIGH PRESSURE OVER THE W ATLC AND LOWER SURFACE PRESSURE OVER NRN SOUTH AMERICA IS PRODUCING FRESH TO STRONG WINDS ACROSS MUCH OF THE BASIN. AN EARLIER ASCAT PASS SHOWED THE STRONGEST WINDS OF 20 TO 30 KT JUST OFFSHORE THE COAST OF COLOMBIA. THESE WEATHER CONDITIONS ARE EXPECTED TO PERSIST THROUGH MON WHEN THE SFC HIGH WILL BEGIN TO SHIFT E AND GRADUALLY WEAKEN. IN THE MEANTIME...GENERALLY FAIR WEATHER CONDITIONS ARE OBSERVED AND EXPECTED TO CONTINUE OVER THE NEXT 24 HOURS ACROSS THE CARIBBEAN REGION AS DEEP LAYERED DRY AIR IS PRESENT ON WATER VAPOR IMAGERY. HOWEVER...SHALLOW MOISTURE EMBEDDED IN THE TRADE WIND FLOW IS MOVING ACROSS THE REGION PRODUCING ISOLATED TO SCATTERED PASSING SHOWERS. THESE PATCHES OF LOW LEVEL MOISTURE ARE MOST IMPACTING THE NE CARIBBEAN FROM THE N LEEWARD ISLANDS TO DOMINICAN REPUBLIC. SIMILAR CLOUDINESS ARE ALSO AFFECTING PARTS OF JAMAICA. ATLANTIC OCEAN... A 1027 MB SURFACE HIGH IS LOCATED SE OF BERMUDA NEAR 30N59W WITH A RIDGE ENVELOPING MOST OF THE WEST AND CENTRAL ATLC...INCLUDING THE BAHAMAS...THE STATE OF FLORIDA AND GREATER ANTILLES. IN THE UPPER LEVELS...A RIDGE EXTENDS FROM THE NW CARIBBEAN ACROSS THE FLORIDA PENINSULA INTO THE WESTERN ATLC WHILE A SHORT-WAVE TROUGH IS DEVELOPING OVER THE SE BAHAMAS AND THE WINDWARD PASSAGE. MODERATE TO STRONG SUBSIDENCE AND THE ASSOCIATED DRY AIR MASS IS RESULTING IN MOSTLY FAIR WEATHER ACROSS THE REGION. FARTHER TO THE E...AN UPPER LEVEL LOW LOCATED NEAR 32N28W SUPPORTS A 1007 MB SURFACE LOW SITUATED NEAR 31N31W. A SURFACE TROUGH EXTENDS FROM THE LOW ALONG 30N28W 27N27W 21N30W. UPPER LEVEL DIFFLUENCE AND LOW LEVEL CONVERGENCE IN THE VICINITY OF THE SURFACE LOW AND TROUGH ARE GENERATING AN AREA OF SCATTERED SHOWERS WITHIN 80-100 NM E OF THE TROUGH N OF 26N. THE REMAINDER OF THE E ATLC IS UNDER THE INFLUENCE OF A NARROW SURFACE RIDGE ANCHORED WELL N OF THE FORECAST AREA. ACROSS THE DEEP TROPICS... A BROAD UPPER LEVEL RIDGE ANCHORED ON A HIGH NEAR 6N49W WITH AXIS ORIENTED W-E ALONG 6N IS ENHANCING CONVECTION ASSOCIATED WITH THE ITCZ. MOSTLY ZONAL FLOW IS NOTED FROM 10-20N BETWEEN THE WEST COAST OF AFRICA AND THE LESSER ANTILLES. A JET STREAM BRANCH WITH CORE WINDS OF 70-100 KT IS LOCATED MIDWAY BETWEEN THE CANARY AND THE CAPE VERDE ISLANDS ENTERING WEST AFRICA THROUGH THE SOUTHERN PORTION OF WESTERN SAHARA. A BAND OF TRANSVERSE HIGH CLOUDS IS NOTED ON SATELLITE IMAGERY ASSOCIATED WITH THE JET. $$ GR