000 AXNT20 KNHC 310602 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 205 AM EDT SAT MAR 31 2007 TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL AMERICA...THE GULF OF MEXICO...THE CARIBBEAN SEA...NORTHEASTERN 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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 0545 UTC. ...THE ITCZ... ITCZ IS CENTERED ALONG 8N12W 3N20W 1N30W 1N40W EQ50W. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS OVER THE SRN COAST OF SIERRA LEONE AND ADJACENT ATLC WATERS FROM 6N-8N BETWEEN 11W-15W. SCATTERED MODERATE IS ALSO WITHIN 120NM N OF THE AXIS BETWEEN 19W-27W. ISOLATED MODERATE IS FROM EQ-5N BETWEEN 30W-39W. ...DISCUSSION... THE GULF OF MEXICO... A 1026 MB SFC HIGH PRES NEAR FRISCO NC CONTINUES TO EXTEND SW OVER THE GULF TONIGHT. THIS IS PRODUCING ABUNDANT 15-20 KT E TO SE WINDS ACROSS THE BASIN WHICH IN TURN ARE GENERATING MODERATE WIND WAVES AND SWELL...MOSTLY IN THE 4-6' RANGE EXCEPT LARGER IN THE STRAITS OF FLORIDA. THE RIDGING ACROSS THE GULF WILL WEAKEN THROUGH TONIGHT IN ADVANCE OF A WEAK COLD FRONT TO PUSH OFF THE TEXAS COAST SAT EVENING. DEEP CONVECTION REMAINS AT A MINIMUM OVER THE GULF THOUGH SCATTERED MODERATE HAS PERSISTED INLAND OVER MEXICO FROM 19N-21N BETWEEN 97W-100W WITH UPSLOPE ELY FLOW. KEY WEST RADAR DATA SHOWS SHOWERS PUSHING THROUGH THE STRAITS OF FLORIDA...LIKELY BEING ENHANCED BY THE TAIL END OF A BACKDOOR COLD FRONT FROM THE ATLC. RIDGING CONTINUES TO DOMINATE THE UPPER LEVELS OVER THE GULF. DRY/STABLE MID TO UPPER AIR ALSO DOMINATES THE BASIN ASIDE FROM BROKEN CIRRUS OVER THE FAR NW AND SW PORTIONS AHEAD OF INLAND CONVECTION. THE CARIBBEAN SEA... MODERATE TO FRESH NE SFC WINDS DOMINATE MUCH OF THE CARIB TONIGHT...THOUGH STRONGER WINDS ARE BEING FELT IN THE ATLC PASSAGES AS STRONG REINFORCING HIGH PRESSURE CENTERED NEAR CAPE HATTERAS NC BUILDS IN. 31/0000 UTC QUIKSCAT SHOWED A BAND OF 25-30 KT NE WINDS IN THE WINDWARD PASSAGE BETWEEN JAMAICA AND THE TURKS AND CAICOS. HIGHER SEAS SHOULD ALSO BE ANTICIPATED IN THESE EXPOSED ATLC PASSAGES...SEE OFFSHORE WATERS FORECAST UNDER MIAOFFNT3 FOR MORE DETAILS. A WEAK FRONTAL BOUNDARY AT THE LEADING EDGE OF THE HIGH WILL PUSH INTO THE NE CARIB LATER TODAY. ALOFT...A BROAD UPPER RIDGE CONTINUES TO DOMINATE FROM ITS ORIGIN OVER THE TROPICAL ATLC. THIS IS ADVECTING HIGH CLOUDS INTO THE CARIB ESPECIALLY S OF 14N E OF 75W. DEEP LAYER TROUGH DOMINATING THE WRN ATLC IS MOSTLY N OF THE AREA. THE ATLANTIC OCEAN... STRONG HIGH PRESSURE IS BUILDING INTO THE WRN ATLC BEHIND A BACK DOOR COLD FRONT THAT ENTERS THE AREA NEAR 32N49W AND CONTINUES SW TO NEAR 21N71W. MODERATE TO STRONG NLY WINDS BEHIND THE FRONT ARE ADVECTING INCREASING STRATOCUMULUS CLOUDS INTO THE AREA N OF 23N BETWEEN 61W-77W. THE FRONT IS ASSOCIATED WITH DEEP LAYER TROUGHING DOMINATING THE WRN ATLC...WITH A MID TO UPPER LOW NOTED NEAR 29N57W. THIS APPEARS TO HAVE DEVELOPED A SFC REFLECTION BASED ON SHORTWAVE IR IMAGERY AND AN EARLIER QUIKSCAT PASS. SCATTERED MODERATE CONVECTION WITH POSSIBLE TSTMS AHEAD OF THIS TROUGHING ARE FROM 26N-33N BETWEEN 50W-54W. A REMNANT SFC TROUGH REMAINS AHEAD OF THE COLD FRONT IN THE CENTRAL ATLC WATERS...ALONG 32N45W 20N51W TO THE WINDWARD ISLANDS NEAR 13N61W. SCATTERED SHOWERS WITH POSSIBLE EMBEDDED TSTMS ARE WITHIN 250 NM MAINLY E OF THIS TROUGH...ESPECIALLY N OF 20N. A 1005 MB LOW IS ATTACHED TO THE TROUGH NEAR 28N47W...WHICH IS EXPECTED TO MOVE NE OF THE AREA DURING SAT. MUCH OF THE REMAINDER OF THE E ATLC IS DOMINATED BY RIDGING AT ALL LEVELS. A 1032 MB SFC HIGH IS MIDWAY BETWEEN THE AZORES AND MADEIRA ISLAND...WHICH IS PRODUCING ABUNDANT FAIR WEATHER AND MODERATE TO STRONG TRADES ACROSS MUCH OF THE AREA E OF 35W. $$ WILLIS