000 AXNT20 KNHC 061757 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 105 PM EST SUN FEB 06 2011 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. ...ITCZ... ITCZ AXIS ANALYZED FROM 06N20W TO 02N34W TO 02N43W THEN INTO THE MOUTH OF THE AMAZON BASIN ACROSS EQUATORIAL BRAZIL. CONVECTION NEAR THE AXIS HAS DIMINISHED IN THE PAST 24 HOURS...WITH SCATTERED MODERATE AND ISOLATED STRONG CONVECTION NOTED WITHIN 210 NM N OF AXIS W OF 38W. ...DISCUSSION... GULF OF MEXICO... A BROAD LONGWAVE TROUGH CONTINUES ACROSS THE U.S. TODAY...WITH SEVERAL SHORTWAVES AND SMALL CYCLONES ROTATING THROUGH THIS FEATURE. BROAD SRN END OF TROUGH CURVED CYCLONICALLY ACROSS MEXICO N OF 23N...WITH SWLY FLOW IN EXCESS OF 100 KT ALOFT ACROSS THE N AND NE GULF. UPPER RIDGE TO THE SE WAS CENTERED OVER THE CARIBBEAN JUST NW OF JAMAICA. AN OLD FRONTAL BOUNDARY REMAINS DRAPED ACROSS THE SE GULF...FROM THE W ATLC SW ACROSS SRN FLORIDA TO JUST SOUTH OF NAPLES THEN CONTINUES RELATIVELY STATIONARY TO NEAR 24N87W...THEN EXTENDS W-SW THEN W AS AN ILL DEFINED WARM FRONT LIFTING N IN INCREASING SLY LLVL FLOW. NARROW BANDS OF SHALLOW CONVECTION WERE DEPICTED BY NWS RADAR NETWORK EXTENDING NE TO SW ACROSS CENTRAL AND N FLORIDA IN THE COOLER AIR NW OF THE FRONT...WHILE PATCHES OF STRATIFORM PRECIP WITH EMBEDDED SHALLOW CONVECTION WAS SPREAD ACROSS THE NE GULF E OF 90W. A SHORTWAVE DIVING S THROUGH THE BACKSIDE OF THE UPPER TROUGH WAS MOVING ACROSS NEW MEXICO AND INTO WRN TEXAS...WITH A ACCOMPANYING SURFACE LOW AND DEVELOPING COLD FRONT. THESE FEATURES ARE FORECAST TO MOVE SE INTO SE AND E TEXAS TONIGHT AND TRANSPORT A NEW COLD FRONT MOVING OFF THE TEXAS AND LOUISIANA COASTS MON MORNING. THE CURRENT OLD FRONT ACROSS THE GULF WILL DRIFT N ACROSS FLORIDA AND THE ERN GULF THROUGH MON MORNING BEFORE THE BOUNDARIES MERGE ACROSS THE FAR SE GULF AND FLORIDAS ATLC WATERS MON NIGHT. CARIBBEAN SEA... WATER VAPOR IMAGERY INDICATES VERY DRY AIR ALOFT ACROSS MOST OF THE BASIN DUE TO A TUTT AXIS EXTENDING E TO W ALONG 15N. STRONG CONVERGENCE ALONG THE N SIDE OF THIS AXIS WAS PRODUCING STRONG SUBSIDENCE ACROSS THE NE CARIB EXTENDING W TO THE WINDWARD PASSAGE. AS MENTIONED ABOVE...AN UPPER ANTICYCLONE WAS CENTERED JUST NW OF JAMAICA WITH RIDGE EXTENDING NE TO NEAR 30N62W. AT LOW LEVELS...MODERATE TO FRESH ELY TRADES CONTINUE ACROSS THE CARIB E OF 80W...WITH WINDS 25-30 KT IN THE SW CARIB AND HIGHEST OFF THE COAST OF COLOMBIA. ABOVE THE BOUNDARY LAYER...LOW LEVEL FLOW HAS BEGUN TO VEER MORE E-SE ACROSS THE NE CARIB AND GREATER ANTILLES AND WILL AID IN FOCUSING AFTERNOON CONVECTION SHIFTED MORE NW THAN IN TYPICAL ELY TRADE WIND FLOW. WEAKER TRADES W OF 80W PREVAILED...WHILE A WELL DEFINED LOW LEVEL CYCLONE APPEARED CENTERED JUST N OF PANAMAS...AND WAS PART OF THE EPAC MONSOONAL CIRCULATION...AND LIGHT TO MODERATE E TO SE WINDS PREVAILED ACROSS NW PORTIONS. CLUSTERS OF STRATOCU WITH BANDS OF SHALLOW CONVECTION WERE NOTED PASSING S OF JAMAICA AND SPREAD ACROSS THE WATERS W OF 82W. TYPICAL UPSLOPE YET SHALLOW CONVECTION SHOULD BE EXPECTED ACROSS THE CARIBBEAN COASTS OF CENTRAL AMERICA THROUGH THIS EVENING. HIGH PRESSURE ACROSS THE CENTRAL ATLC WILL SINK SLIGHTLY SE OVERNIGHT AND TIGHTEN THE PRESSURE GRADIENT ACROSS THE TROPICAL ATLC AND INTO THE ERN CARIBBEAN...AND FRESHEN THE TRADE WIND FLOW E OF 70W. THIS WILL INCREASE THE FREQUENCY OF PASSING SHOWERS ACROSS THE ERN CARIB THIS AFTERNOON THROUGH MON MORNING. ATLANTIC OCEAN... UPPER LEVEL TROUGHING ACROSS THE CENTRAL AND NE CONUS IS SUPPORTING A COLD FRONT THAT WAS ANALYZED OFFSHORE OF THE EASTERN U.S. SEABOARD AT 1200 UTC FROM 32N75.5W SW TO THE FLORIDA PENINSULA N OF VERO BEACH. MOSAIC DOPPLER RADAR IMAGERY INDICATES MID-LEVEL MOISTURE OVERRUNNING THE FRONTAL BOUNDARY PRODUCING NARROW BANDS OF SHALLOW SCATTERED SHOWERS WITHIN 180 NM NW OF THE FRONT. THE REMAINDER OF THE N ATLC S OF 30N IS UNDER THE INFLUENCE OF THE ATLANTIC HIGH PRES RIDGE CENTERED ON A PAIR OF 1028 MB HIGHS...WITH A MEAN CENTERPOINT NEAR 34N43W. A LOW LEVEL TROUGH HAS MOVED OFF THE W COAST OF AFRICA IN THE PAST FEW DAYS...CROSSED THE CAPE VERDES...AND WAS ALONG ABOUT 30W THIS MORNING...AND HELPING TO PRODUCE A MODERATE PRES GRADIENT ACROSS THE TROPICAL ATLC...YIELDING NELY TRADES OF 20-25 KT S OF 21N FROM 30W TO JUST E OF THE LESSER ANTILLES. THE LOW TO MID LEVEL REMNANTS OF A TUTT INDUCED TROUGH...AND ITS ASSOCIATED ENHANCED MOISTURE...WERE MOVING W TO W-NW ACROSS THE NE CARIB AND ADJACENT ATLC WATERS PRODUCING SCATTERED CLUSTERS OF TRADEWIND SHOWERS THAT WILL BE ENHANCED AS THEY MOVE ACROSS THE ISLANDS THIS AFTERNOON AND EVENING. EAST OF 30W...DRY AND STABLE SAHARAN AIR DOMINATED FROM N OF THE ITCZ TO THE CANARY ISLANDS...YIELDING NEARLY CLOUD FREE SKIES. TO THE W OF THIS SAHARAN AIR WAS A WEAK LOW TO MID LEVEL INVERTED TROUGH THAT EXTENDED FROM NEAR 20N31W SW TO NEAR 12N36W...AND WAS ENTRENCHED IN A ZONE OF ENHANCED LOW LEVEL MOISTURE THAT WAS PRODUCING A BROAD AREA OF SCATTERED TO NUMEROUS SHALLOW CONVECTION...WITH ISOLATED MODERATE CONVECTION. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ STRIPLING