000 AXNT20 KNHC 122345 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 705 PM EST TUE FEB 12 2008 TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL AMERICA...THE GULF OF MEXICO...THE CARIBBEAN SEA...NORTHERN 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 ...THE ITCZ... THE ITCZ AXIS IS CENTERED ALONG 6N11W 3N20W 2N30W 2N40W EQ48W INTO NE BRAZIL. SCATTERED MODERATE TO ISOLATED STRONG CONVECTION IS WITHIN 120-130 NM N OF AXIS BETWEEN 23W-38W...AND WITHIN 100-120 NM S OF AXIS BETWEEN 30W-34W. SIMILAR CONVECTION IS FROM 5N-7N BETWEEN 16W-20W. ...DISCUSSION... THE GULF OF MEXICO... AS OF 21Z...A COLD FRONT HAS ENTERED THE NW CORNER OF THE GULF. THE MOSAIC DOPPLER RADAR FROM THE SE U.S. SHOWS A STRONG BAND OF SHOWERS AND TSTMS ASSOCIATED WITH THIS FRONT. THE STRONGEST TSTMS ARE MOVING ACROSS SE LOUISIANA AND THE N GULF WATERS N OF 28N BETWEEN 90W-95W. A LONG WAVE TROUGH EXTENDING FROM JUST WEST OF THE GREAT LAKES SWWD TO CENTRAL TEXAS AND NE MEXICO SUPPORTS THIS FRONTAL ZONE. A STRONG SHORT WAVE TROUGH IS MOVING EWD AROUND THE BASE OF THIS TROUGH...AND ACROSS THE E-CENTRAL GULF. THIS FEATURE IS GENERATING A BROAD AREA OF SHOWERS WITH EMBEDDED TSTMS THAT IS AFFECTING THE E PORTION OF THE GULF AND THE STATE OF FLORIDA. AS A RESULT...A TORNADO WATCH HAS BEEN ISSUED FOR ALL OF SOUTH FLORIDA UNTIL 11 PM EST. LIGHTNING DATA REVEALS SCATTERED TSTMS OVER THE SE PORTION OF THE GULF AND NEAR 27N86W. A WARM FRONT IS ALSO ANALYZED ACROSS CENTRAL FLORIDA JUST N OF LAKE OKEECHOBEE. THIS FRONT IS SPREADING ALL THIS SHOWER/TSTM ACTIVITY NORTH. SLY SURFACE FLOW DOMINATES THE GULF AHEAD OF THE COLD FRONT WHILE MODERATE TO STRONG NLY WINDS ARE FOUND BEHIND THE FRONTAL BOUNDARY...WHICH IS FORECAST TO MOVE SE ACROSS THE AREA REACHING FROM THE FLORIDA PANHANDLE TO BAY OF CAMPECHE WED MORNING. THE CARIBBEAN SEA... THE SHORT WAVE TROUGH OVER THE E-CENTRAL GULF OF MEXICO DIGS INTO THE YUCATAN CHANNEL AND NW PORTION OF THE CARIBBEAN SEA. DIFFLUENCE AHEAD OF THIS TROUGH IS HELPING TO INDUCE SOME SHOWER ACTIVITY OVER WESTERN CUBA. THE REMAINDER OF THE BASIN IS UNDER THE INFLUENCE OF A BROAD RIDGE ANCHORED ON A HIGH OVER N SOUTH AMERICA. SWLY UPPER LEVEL FLOW ON THE WESTERN SIDE OF THIS RIDGE IS ADVECTING UPPER LEVEL MOISTURE FROM THE EPAC INTO THE SW CARIBBEAN THROUGH COSTA RICA...PANAMA AND N COLOMBIA. PRES GRADIENT BETWEEN A SFC HIGH N OF AREA AND THE COLOMBIAN LOW IS PRODUCING MODERATE TRADEWINDS...PARTICULARLY OVER THE E AND CENTRAL CARIBBEAN WITH THE STRONGEST WINDS AS USUAL ALONG THE COAST OF N COLOMBIA. SMALL PATCHES OF LOW LEVEL CLOUDS DOTS THE BASIN. SOME OF THEM ARE MOVING WWD BETWEEN THE N LEEWARD ISLANDS AND HISPANIOLA. THE ATLANTIC OCEAN... A COLD FRONT ENTERS THE AREA NEAR 31N48W THEN CONTINUES SW TO 25N70W. AT THIS POINT...A WARM FRONT EXTENDS WWD TO CENTRAL FLORIDA AND THE EASTERN GULF OF MEXICO NEAR 27N86W. A 80 NM WIDE BAND OF BROKEN TO OVERCAST LOW/MID CLOUDS IS RELATED TO THE FRONT. A DIFFERENCE IN PRES BETWEEN A 1031 MB HIGH LOCATED MIDWAY BETWEEN CAPE HATTERAS AND BERMUDAS AND LOWER PRES OVER THE SE U.S WILL PRODUCE GALE FORCE WINDS ACROSS THE SW N ATLC JUST E OF N FLORIDA AND WEST OF 70W TONIGHT. A GALE WARNING IS ALREADY IN EFFECT. A RIDGE/TROUGH/RIDGE/TROUGH PATTERN DOMINATES THE FORECAST AREA WITH A STRONG UPPER LEVEL TROUGH OVER THE E ATLC. THIS TROUGH EXTENDS FROM A VIGOROUS CUT-OFF LOW LOCATED N OF THE MADEIRA ISLANDS SWWD REACHING THE CAPE VERDE ISLANDS. A SHORT WAVE TROUGH IS E OF THE LESSER ANTILLES ALONG 54W/55W. AN AREA OF MAINLY LOW CLOUDS AND ISOLATED SHOWERS IS OBSERVED AHEAD OF THE TROUGH AXIS. $$ GR