000 AXNT20 KNHC 222349 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 805 PM EDT THU MAR 22 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 2315 UTC. ...ITCZ... ITCZ AXIS IS CENTERED ALONG 9N14W 4N20W 1N31W EQ45W AND INTO NE BRAZIL NEAR 1S49W. SCATTERED MODERATE CONVECTION IS WITHIN 240 NM N OF THE AXIS BETWEEN 26W-40W. ...DISCUSSION... GULF OF MEXICO... MOSTLY FAIR WEATHER IS THE RULE ACROSS THE GULF WITH THE EXCEPTION BEING THE EXTREME SE CORNER. A DEEPENING UPPER LEVEL SHORTWAVE ALONG WITH A SFC TROUGH IS GENERATING A GOOD AMOUNT OF MOISTURE ACROSS THE BAHAMAS. ISOLATED PATCHES OF THIS MOISTURE ARE BEING STEERED WWD BY STIFF ELY LOW-LEVEL WINDS ACROSS S FLORIDA AND THE SE GULF. THESE WINDS ARE FLOWING AROUND THE SW PERIPHERY OF STRONG HIGH PRES IN THE CENTRAL ATLC. AN AMPLIFIED MID/UPPER LEVEL RIDGE IS ALIGNED ALONG 97W. THIS RIDGE IS DOWNSTREAM OF A STRONG UPPER LEVEL LOW OVER BAJA CALIFORNIA. ABUNDANT MOISTURE IS BEING ADVECTED NEWD BETWEEN THE UPPER FEATURES ACROSS MEXICO AND INTO THE CENTRAL U.S. BARELY CLIPPING THE NW CORNER OF THE GULF. ELSEWHERE DRY STABLE AIR ALOFT IS KEEPING CONDITIONS TRANQUIL. LOOKING AHEAD A COUPLE OF DAYS...NWP MODELS ARE IN GENERAL AGREEMENT SHOWING THE UPPER RIDGE BUILDING E AS THE SHORTWAVE DEEPENS IN THE CARIB. THESE FEATURES ALONG WITH SFC HIGH PRES PUSHING S WILL PROMOTE FAIR WEATHER...LIKELY SUPPRESSING THE SHOWERS IN THE SE GULF. CARIBBEAN... SCATTERED SHOWERS AND TSTMS CONTINUE TO AFFECT MUCH OF HISPANIOLA...ERN CUBA...JAMAICA AND SURROUNDING OFFSHORE WATERS. THE CONTRIBUTING ELEMENTS ARE A SFC TROUGH WHICH EXTENDS FROM THE ATLC INTO THE WINDWARD PASSAGE AND UPPER DIFFLUENCE/MOIST SWLYS AHEAD OF A MID TO UPPER LEVEL SHORTWAVE TROUGH AXIS. THESE FEATURES ARE SUPPLYING INSTABILITY FOR THE CONTINUED UNSETTLED WEATHER...ESPECIALLY JUST N OF THE REGION. OTHERWISE THE CARIB IS FAIRLY QUIET WITH TYPICAL PATCHES OF LOW LEVEL MOISTURE PUSHING WWD STEERED BY MODERATE TRADES. THE WRN PERIPHERY OF AN UPPER RIDGE COVERS THE ERN CARIB ADVECTING SCATTERED HIGH CLOUDS ACROSS THE REGION. OVER THE NEXT COUPLE OF DAYS...SHOWERS AND TSTMS ARE LIKELY TO PERSIST IN A SIMILAR LOCATION AND PERHAPS INCREASE IN COVERAGE AS THE SFC BOUNDARY HANGS AROUND AND THE UPPER SHORTWAVE SHARPENS OVER THE NW CARIB. ATLANTIC... LARGE SCALE PATTERN OVER THE WRN ATLC IS DOMINATED BY THE SRN PERIPHERY OF A STRONG 1037 MB HIGH LOCATED WELL NE OF BERMUDA. A COUPLE OF SFC TROUGHS ARE EMBEDDED IN THIS RIDGE HELPING TO TIGHTEN THE GRADIENT LEADING TO STRONG ELY WINDS/WIND WAVES. THE FIRST TROUGH IS IN THE BAHAMAS ALONG 76W FROM 24N-29N. THIS A REFLECTION OF A SMALL MID LEVEL LOW BETWEEN SFL AND WRN BAHAMAS. ASSOCIATED NUMEROUS SHOWERS AND TSTMS ARE WITHIN 240 NM E OF THE TROUGH. SECOND TROUGH IS THE REMNANTS OF A LONG LIVED STATIONARY FRONT...NOW ALONG 29N55W 22N64W TO THE WINDWARD PASSAGE. LOW-LEVEL CONVERGENCE NEAR THIS BOUNDARY ALONG WITH UPPER LEVEL DIFFLUENCE IS GENERATING SCATTERED SHOWERS AND TSTMS WITHIN 180 NM OF THE TROUGH AXIS N OF 22N AND WITHIN 240 NM S OF THERE. A GOOD AMOUNT OF MOISTURE IS LIKELY TO PERSIST IN THIS REGION OVER THE NEXT FEW DAYS AS THE SFC TROUGH REMAINS NEARLY STATIONARY AND THE UPPER PATTERN REMAINS DIFFLUENT. MUCH OF THE REMAINDER OF THE DISCUSSION AREA IS DOMINATED BY MODERATE TRADE FLOW S OF A 1034 MB HIGH BETWEEN THE AZORES AND PORTUGAL. INTERRUPTING THE RIDGING IS A WEAK SFC REFLECTION OF AN UPPER LOW SPINNING NEAR 29N26W. LIGHT SHOWERS ARE POSSIBLE WITHIN 150 NM N AND E OF THE UPPER SYSTEM...BUT SHOULD DIMINISH THROUGH SAT AS THE UPPER LOW WEAKENS AND SHIFTS ENE. STRONG SFC HIGH PRES WILL SEEP SWD INTO THE CENTRAL/ERN ATLC OVER THE NEXT COUPLE OF DAYS MAINTAINING THE WIDESPREAD FAIR WEATHER. $$ CANGIALOSI