000 AXNT20 KNHC 082307 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 805 PM EDT SAT APR 08 2006 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...WEATHER OBSERVATIONS... RADAR...AND METEOROLOGICAL ANALYSIS. BASED ON 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 2245 UTC. ...ITCZ... ITCZ AXIS IS CENTERED ALONG 7N11W 3N30W 1S49W. WIDELY SCATTERED MODERATE CONVECTION FROM 1N-4N BETWEEN 17W-30W. A FEW TSTMS ARE WITHIN 75 NM OF 2N14W. ISOLATED SHOWERS/TSTMS ARE S OF 4N W OF 40W. ...DISCUSSION... GULF OF MEXICO... COLD FRONT IS SLOWLY MOVING ACROSS THE NE GULF WHILE RACING SOUTHWARD IN THE SW GULF. FRONT HAS JUST PAST PENSACOLA FLORIDA SW TO 25N90W THEN INTO SW MEXICO NEAR 20N96.5W HANGING UP IN THE HIGH MOUNTAINS. POTENT SHORTWAVE MOVING ACROSS THE SE USA IS CAUSING SEVERE TSTMS ACROSS NE FLORIDA AND SE GEORGIA BUT INSTABILITY IS PRETTY LIMITED OVER GULF WATERS WITH JUST A FEW ISOLATED TSTMS N OF 29N. AHEAD OF THE FRONT...WEAK 1008 MB LOW.. JUST A SWIRL OF LOW CLOUDS IS IN THE BAY OF CAMPECHE NEAR 20N94.5W DRIFTING SE. BEHIND THE LOW WINDS PICK UP BUT THE FRONT APPEARS TO BE A COUPLE DEGREES BEHIND THE FRONT. SHOWERS/TSTMS ARE LIKELY FOR MOST OF S FLORIDA TOMORROW AS THE FRONT CONTINUES TO MOVE SOUTHWARD WITH EVEN A CHANCE FOR SOME SEVERE TSTMS TOMORROW. THE FRONT IS FORECAST TO LEAVE THE PENINSULA EARLY MON WITH FRESH 25 KT NE WINDS BEHIND THE BOUNDARY. DRY AIR AT THE SURFACE AND ALOFT WILL DOMINATE THE REST OF THE WEEKEND BEHIND THE FRONT N OF 26.5N. NO FRONTS ARE ON THE HORIZON YET BUT POSSIBLE NON-TROPICAL LOW PRESSURE DEVELOPMENT OFFSHORE OF FLORIDA SHOULD KEEP MOST OF THE NORTHERN GULF COAST IN PLEASANT WEATHER FOR THE UPCOMING WEEK. CARIBBEAN SEA... MIDDLE TO UPPER LEVEL RIDGE COVERS MOST OF THE BASIN WITH A TROUGH FURTHER EAST OVER THE NORTHEASTERN CARIBBEAN NEAR THE LEEWARD ISLANDS. MODERATE/STRONG SUBSIDENCE IS THE RULE SAVE A FEW HIGH CLOUDS STREAMING OVER THE AREA. WEAK SHALLOW SURFACE LOW IS NEAR 10.5N79W.. MORE AMPLIFIED THAN NORMAL IN THE TYPICAL CYCLONIC WIND REGIME OF THE SW CARIBBEAN. TYPICAL TRADEWIND SHOWERS ARE AROUND IN THE E CARIBBEAN WITH A FEW TSTMS FIRING OVER THE HIGHER TERRAIN OF THE GREATER ANTILLES. COLD FRONT OVER THE GULF WILL AFFECT THE WEATHER STARTING LATE TOMORROW OVER CUBA BY INCREASING THE CHANCES OF SHOWERS/TSTMS... SHIFTING FARTHER SE TO ERN CUBA BY LATE MON AND HISPANIOLA ON TUE. A LITTLE DRIER AIR COULD MAKE ITS WAY INTO THE NW CARIBBEAN BUT IT IS EXPECTED TO BE SHORT-LIVED. ATLANTIC OCEAN... UPPER RIDGING CONTROLS THE NW ATLC WITH A 1025 MB HIGH E OF BERMUDA PROVIDING FAIR SKIES. INCREASING HIGH CLOUDS ARE THE HARBINGER OF A PATTERN CHANGE WITH A FRONT SCHEDULED TO MOVE INTO THE AREA OVERNIGHT AND SHOWERS/TSTMS LOOK LIKELY ALONG THIS BOUNDARY. FARTHER E... MID/UPPER TROUGH IS ALONG 20N46W TO 32N49W WITH AN UPPER LOW NEAR 29N49W. TROUGH IS CAUSING A LARGE AREA OF BROKEN/OVERCAST HIGH CLOUDS N OF 25N BETWEEN 30W-50W IN ADDITION TO ISOLATED SHOWERS/TSTMS. MOST OF THE WEATHER LIES E OF A SURFACE TROUGH FROM A WEAK 1015 MB LOW NEAR 25N47W TO A 1013 MB LOW NEAR 32N47W. CLOUDS ARE ALSO ON THE INCREASE IN THE E ATLC AS A SHORTWAVE NEAR 26N38W MOVES RAPIDLY EASTWARD... SPREADING HIGH CLOUDS N OF 20N E OF THE SHORTWAVE. A FEW SHOWERS ARE POSSIBLE BENEATH THE CIRRUS CANOPY BUT IT LOOKS MOSTLY DRY. WEAKENING COLD FRONT IS ALONG 31N19W TO 22N36W PROVIDING A BRIEF INCREASE IN BROKEN LOW CLOUDS. WEAK UPPER RIDGING CONTROLS THE TROPICAL E ATLC WITH PLENTY OF SUBSIDENCE ALOFT KEEPS CLOUDS TO A MINIMUM. ITCZ CONVECTION IS ACTIVE E OF 30W IN RATHER DIFFLUENT FLOW ALOFT. UPPER RIDGING REMAINS FARTHER N THAN AVERAGE FOR THIS TIME OF THE YEAR WITH TRADES NEAR OR SLIGHTLY BELOW AVERAGE IN THE TROPICAL ATLC. WEAK TROPICAL WAVE MAY BE ALONG ABOUT 28W BUT IT IS VERY LOW-LATITUDE (S OF 6N) AND NEARLY IMPOSSIBLE TO TRACK. $$ BLAKE