000 AXNT20 KNHC 162347 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 805 PM EDT SAT APR 16 2011 TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL AMERICA...GULF OF MEXICO...CARIBBEAN SEA...NORTHERN SECTION OF SOUTH AMERICA...AND 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 ANALYZED FROM SW AFRICA ALONG 5N7W 2N17W 3N30W 1N36W 1N51W. SCATTERED MODERATE/STRONG CONVECTION IS FROM THE ITCZ TO JUST S OF THE EQUATOR BETWEEN 17W-21W WITH CLUSTERS DOTTING THE AREA FROM 2N TO S OF THE EQUATOR BETWEEN 1W-15W. SCATTERED MODERATE WITH EMBEDDED CLUSTERS OF ISOLATED STRONG CONVECTION ARE FROM 6N TO S OF THE EQUATOR BETWEEN 30W-37W. ...DISCUSSION... GULF OF MEXICO... THE PRIMARY FOCUS TONIGHT IS THE COLD FRONT OVER THE E CONUS PRODUCING SEVERE WEATHER FROM SOUTH CAROLINA NORTHWARD. THE COLD FRONT EXTENDS INTO THE E GULF AT 16/2100 UTC ACROSS NE FLORIDA NEAR CEDAR KEY ALONG 26N86W TO 24N91W WHERE IT BECOMES STATIONARY TO 22N94W. ISOLATED SHOWERS ARE OVER THE E GULF WITHIN 30 NM E OF THE COLD FRONT. THE UPPER TROUGH SUPPORTING THIS FRONT IS MOVING RAPIDLY OVER THE E CONUS E OF THE MISSISSIPPI VALLEY INTO THE NE GULF N OF 27N E OF 90W. THE REMAINDER OF THE GULF IS DOMINATED BY AN UPPER RIDGE AXIS THAT ACTUALLY EXTENDS ACROSS THE CARIBBEAN INTO THE W ATLC. WEAK SURFACE RIDGE IS NW OF THE FRONT WITH A 1021 MB HIGH ALONG THE TEXAS COAST JUST S OF GALVESTON. THE SE PORTION OF THE COLD FRONT WILL STALL AND BECOME DIFFUSE AS IT MOVES ACROSS THE SE GULF THROUGH SUN WHILE THE N PORTION WILL MOVE INTO THE W ATLC LATER THIS EVENING. SURFACE RIDGE BEHIND THE FRONT WILL BUILD ACROSS THE NE GULF ALLOWING FRESH SE FLOW OVER THE W GULF BY SUN. SE WINDS WILL INCREASE ACROSS THE ENTIRE GULF EARLY NEXT WEEK AHEAD OF AN APPROACHING TROUGH MOVING THROUGH THE SOUTHERN PLAINS. CARIBBEAN SEA... AN UPPER RIDGE EXTENDS FROM THE E PACIFIC REGION ACROSS THE W CARIBBEAN FROM NICARAGUA TO ACROSS CENTRAL CUBA INTO THE W ATLC. AN UPPER TROUGH DIPS S OVER THE NE CARIBBEAN FROM HISPANIOLA TO THE LEEWARD ISLANDS N OF 15N. A SECOND UPPER RIDGE IS OVER THE SE CARIBBEAN COVERING THE S CARIBBEAN S OF 15N E OF 80W. TROPICAL MOISTURE IS BEING DRAWN ACROSS THE SE CARIBBEAN DUE TO THIS UPPER FLOW GENERATING SCATTERED SHOWERS AND POSSIBLE ISOLATED THUNDERSTORMS WITHIN 90 NM OF LINE FROM THE PANAMA CANAL ALONG 13N71W ACROSS THE WINDWARD ISLANDS NEAR SAINT VINCENT. LIGHT TO MODERATE TRADE WINDS PREVAIL ACROSS THE BASIN DUE TO THE BROAD PRESSURE GRADIENT. THESE TRADE WINDS WILL CONTINUE OVER MOST OF THE CARIBBEAN THROUGH NEXT WEEK. ATLANTIC OCEAN... AN UPPER RIDGE EXTENDS FROM THE CARIBBEAN ACROSS CENTRAL CUBA TO BEYOND 32N74W. AFTERNOON SHOWERS/THUNDERSTORMS THAT DEVELOPED OVER S FLORIDA ARE DIMINISHING BUT STILL PRODUCING ISOLATED SHOWERS OFF THE E FLORIDA COAST. AN UPPER LEVEL TROUGH IS TO THE E EXTENDING S TO OVER THE NE CARIBBEAN SUPPORTING A SURFACE TROUGH THAT EXTENDS FROM 30N63W TO 25N61W AND IS GENERATING SCATTERED SHOWERS/ISOLATED THUNDERSTORMS WITHIN 90 NM E AND 30 NM W OF THE SURFACE TROUGH AXIS. A BROAD UPPER RIDGE AXIS IS OVER THE CENTRAL ATLC AND EXTENDS FROM 20N43W TO BEYOND 32N54W GENERATING BROKEN/OVERCAST MULTILAYERED CLOUDS WITH ISOLATED SHOWERS COVERING A BROAD AREA FROM 15N-30N BETWEEN 40W-58W. A DEEP LAYERED LOW IS OVER THE E ATLC WITH THE UPPER LOW CENTERED NEAR 30N26W AND A 1000 MB SURFACE LOW NEAR 28N28W. A DISSIPATING OCCLUDED FRONT EXTENDS N OF THE LOW WITH A DISSIPATING COLD FRONT ENTERING THE REGION NEAR 32N22W ALONG 23N22W TO 16N31W. A RE-ENFORCING SURFACE TROUGH EXTENDS FROM 30N27W ALONG 27N25W 24N31W TO 27N39W. ISOLATED SHOWERS ARE N OF 28N BETWEEN 18W-30W. A SURFACE TROUGH IS IN THE W TROPICAL ATLC JUST E OF THE LEEWARD ISLANDS EXTENDING FROM 19N59W TO 14N57W WITH ISOLATED SHOWERS WITHIN 120 NM E OF THE TROUGH AXIS. FRESH S FLOW WILL INCREASE THIS EVENING OFF NE FLORIDA AHEAD OF COLD FRONT CURRENTLY IN THE GULF OF MEXICO. THE FRONT WILL STALL FROM 31N69W TO THE FLORIDA KEYS BY LATE SUN THEN BECOME DIFFUSE THROUGH SUN NIGHT. THE SURFACE TROUGH WILL LINGER IN THE W TROPICAL ATLC THROUGH MON THEN SHIFT TO THE N OF THE LEEWARD ISLANDS BY MIDWEEK. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ PAW