000 AXNT20 KNHC 132341 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 805 PM EDT TUE MAR 13 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 5N10W 2N25W 3N40W EQ50W. WIDELY SCATTERED MODERATE CONVECTION IS FROM 3N-6N E OF 16W. SIMILAR CONVECTION IS S OF 3N BETWEEN 35W-50W. CLUSTERS OF SCATTERED MODERATE/ISOLATED STRONG CONVECTION ARE OVER NE BRAZIL AND SOUTHERN LIBERIA. ...DISCUSSION... GULF OF MEXICO... A RATHER VIGOROUS MID/UPPER LEVEL CUT-OFF LOW IS SPINNING OVER THE TEXAS PANHANDLE WHILE A BROAD UPPER RIDGE DOMINATES THE ENTIRE GULF... WITH THE AXIS ALONG THE FAR E GULF/FLORIDA PENINSULA. UPPER LEVEL DIFFLUENCE BETWEEN THESE TWO FEATURES IS PRODUCING AN AREA OF SHOWERS AND PROBABLY ISOLATED TSTMS IN THE NW CORNER OF THE GULF. A SFC TROUGH IS ANALYZED THERE AND GOES FROM 29N93W TO 23N95W. DOPPLER RADAR SHOWS AN AREA OF SHOWERS AND TSTMS OVER EASTERN TEXAS JUST AHEAD OF THE MID/UPPER LOW MENTIONED ABOVE. A PLUME OF HIGH CLOUDS IS CROSSING THE S PORTION OF THE REGION AND IS ASSOCIATED WITH A SUBTROPICAL JETSTREAM THAT CROSSES SOUTH-CENTRAL MEXICO INTO THE GULF. A SURFACE RIDGE FROM THE W ATLC COVERS THE SE US AND THE GULF ANCHORED BY A 1027 SFC HIGH LOCATED NEAR 31N73W. ACCORDING TO THE COMPUTER MODEL...THE UPPER LOW IS EXPECTED TO WEAKEN DURING THE NEXT DAY OR SO...BUT A SHORTWAVE TROUGH WILL REMAIN MOVING E ACROSS THE GULF. MEANWHILE...THE SFC RIDGE WILL ALSO RETREAT ALLOWING LOW-LEVEL RETURN FLOW TO DEVELOP ACROSS MUCH OF THE AREA. A COLD FRONT IS FORECAST TO MOVE OFF THE TEXAS COAST THU NIGHT. CARIBBEAN... BROAD UPPER RIDGE COVERS THE ENTIRE CARIBBEAN SEA WITH TWO HIGHS. ONE IS CENTERED IN THE TROPICAL EPAC NEAR 7N88W...THE SECOND ONE IS OVER N SOUTH AMERICA. IN BETWEEN...THERE IS A WEAK TROUGH THAT EXTENDS FROM E CUBA/JAMAICA TO COSTA RICA. DRY AND STABLE AIR ALOFT EXISTS OVER MUCH OF THE BASIN WITH SOME UPPER LEVEL MOISTURE MOVING INTO THE NW CORNER OF THE AREA FROM THE GULF. IN THE LOWER LEVELS...PATCHES OF LOW TO MID LEVEL CLOUDS ARE BEING STEERED BY MODERATE TO FRESH NELY TRADES ACROSS THE SEA. A SFC TROUGH FROM THE CENTRAL ATLC DIGS INTO THE NE CARIBBEAN AND IS AFFECTING THE LEEWARD/VIRGIN ISLANDS. THE SAN JUAN DOPPLER RADAR IS SHOWING LINES OF SHOWERS AND ISOLATED TSTMS CROSSING THE ISLANDS. HIGH PRES OVER THE SE U.S. AND W ATLC WILL KEEP STRONG TRADE WINDS OVER THE CENTRAL AND WRN CARIBBEAN AT LEAST DURING THE NEXT 24 HOURS. WESTERN AND CENTRAL ATLANTIC... A TROUGH/RIDGE/TROUGH PATTERN DOMINATES THE FORECAST AREA. AN AMPLIFYING UPPER LEVEL TROUGH IS OVER THE W-CENTRAL ATLC COVERING THE AREA W OF 50W. THE ASSOCIATED FRONTAL BOUNDARY ENTERS THE AREA NEAR 32N50W AND EXTENDS SSW TO A 1014 MB FRONTAL WAVE NEAR 28N53W. A SFC TROUGH CONTINUES SW FROM THE LOW TO THE LEEWARD ISLANDS. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS JUST AHEAD OF THE LOW/FRONTAL SYSTEM FROM 24N TO BEYOND 31N. SFC HIGH PRES DOMINATES THE WRN ATLC BEHIND THE FRONT. UNDER A NELY WINDS FLOW...FRAGMENTS OF LOW-LEVEL CLOUDS WITH EMBEDDED WEAK SHOWERS ARE MOVING ACROSS THE SOUTHERN BAHAMAS. OVER THE NEXT DAY OR SO...NWP MODELS SHOW THE FRONTAL BOUNDARY MOVING SLOWLY E KEEPING SOME LOW LEVEL MOISTURE OVER THE NE CARIBBEAN. EASTERN ATLANTIC... A STRONG CUT-OFF LOW IS OVER THE MADEIRA ISLANDS WITH A TROUGH EXTENDING SWWD TO NEAR 15N35W. DRY AND STABLE AIR ALOFT IS ALONG THE TROUGH AXIS WHILE ABUNDANT UPPER LEVEL MOISTURE IS SEEN SE OF THE TROUGH AXIS RELATED TO A TROPICAL JETSTREAM WITH CORE WINDS OF AROUND 75 KT. AT THE SURFACE...A WELL-DEFINED OCCLUDED 1013 MB LOW IS DRIFTING S BETWEEN THE MADEIRA AND THE CANARY ISLANDS. A PRE-FRONTAL TROUGH LIES ALONG THE COAST OF WESTERN SAHARA. THE PRESSURE DIFFERENCE BETWEEN THE OCCLUDED LOW AND STRONG SFC RIDGE OVER THE E ATLC IS GENERATING A LARGE AREA OF STRONG NLY WINDS N OF 20N BETWEEN 18W-29W. $$ GR