000 AXNT20 KNHC 150554 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 205 AM EDT FRI APR 15 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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 0515 UTC. ...ITCZ... ITCZ AXIS IS ANALYZED ALONG 06N10W 01N24W CROSSING THE EQUATOR NEAR 39W...THEN INTO NE BRAZIL NEAR 02S43W. ISOLATED MODERATE CONVECTION IS FROM THE EQUATOR TO 05N BETWEEN 16W-25W...AND FROM THE EQUATOR TO 04N BETWEEN 27W-41W. ...DISCUSSION... GULF OF MEXICO... W-NW FLOW ALOFT IS ACROSS MUCH OF THE GULF BETWEEN AN UPPER LEVEL TROUGH ACROSS THE U.S. CENTRAL PLAINS AND AN UPPER LEVEL ANTICYCLONIC CIRCULATION CENTERED OVER SOUTHERN MEXICO NEAR 15N95W. THE RIDGE AXIS ALOFT EXTENDS N-NE OVER THE YUCATAN PENINSULA TO BEYOND THE FLORIDA PENINSULA NEAR 30N77W. RECENT SHIP AND BUOY OBSERVATIONS INDICATE S-SE RETURN FLOW ACROSS THE ENTIRE BASIN WHICH IS EXPECTED TO STRENGTHEN SLIGHTLY AND PERSIST THROUGH THE OVERNIGHT AND INTO THE MORNING HOURS OF FRIDAY AHEAD OF THE NEXT COLD FRONT. THE COLD FRONT IS FORECAST TO EMERGE OFF THE TEXAS GULF COAST BY FRIDAY AFTERNOON. EASTWARD PROGRESSION OF THE FRONT THROUGH THE WEEKEND WILL ALLOW HIGH PRESSURE TO BUILD IN ACROSS THE WESTERN GULF THROUGH LATE SATURDAY. CARIBBEAN SEA... AN AMPLIFIED MIDDLE TO UPPER LEVEL TROUGH IS LOCATED OVER THE WESTERN CARIBBEAN WITH AXIS EXTENDING INTO THE BASIN FROM NORTH OF HISPANIOLA NEAR 20N70W S-SW TO EASTERN PANAMA NEAR 08N78W. STRONG SUBSIDENCE AND DRY AIR ACCOMPANY THIS UPPER LEVEL FEATURE AND THESE FACTORS CONTINUE TO PROVIDE OVERALL CLEAR SKIES AND FAIR CONDITIONS ACROSS THE WESTERN CARIBBEAN W OF 70W. EAST OF THE TROUGH AXIS HOWEVER...SW FLOW IS ADVECTING UPPER LEVEL MOISTURE ACROSS THE FAR EASTERN CARIBBEAN AND LESSER ANTILLES NE INTO THE TROPICAL NORTH ATLC. WIDELY SCATTERED SHOWERS ARE OCCURRING E OF 70W WITH MOST OF THIS ACTIVITY FOCUSED IN THE VICINITY OF A SURFACE TROUGH ANALYZED FROM 12N65W TO 20N63W. ELSEWHERE...EASTERLY TRADES REMAIN FAIRLY LIGHT...WITH THE EXCEPTION OF STRONGER WINDS NEAR THE COAST OF COLOMBIA...DUE TO A RELAXED PRESSURE GRADIENT ACROSS THE ENTIRE BASIN. ATLANTIC OCEAN... A MIDDLE TO UPPER LEVEL TROUGH IS OVER THE W ATLC WITH AXIS ALONG 32N67W TO NORTHERN HISPANIOLA NEAR 20N70W. THE UPPER LEVEL TROUGH SUPPORTS A DISSIPATING COLD FRONT ANALYZED INTO THE DISCUSSION AREA NEAR 32N69W EXTENDING SW TO NEAR 28N73W. FRONTAL TROUGHING EXTENDS WEST TO THE FLORIDA PENINSULA NEAR FORT LAUDERDALE HOWEVER MUCH OF THE BOUNDARY W OF 73W HAS LOST ALL UPPER LEVEL SUPPORT. ISOLATED SHOWERS ARE WITHIN 30 NM EITHER SIDE OF THE COLD FRONT...WHILE LINGERING ISOLATED LOW-TOPPED SHOWERS ARE OCCURRING OVER THE NW BAHAMAS FROM 25N-27N BETWEEN 76W-79W. A WEAK HIGH PRESSURE RIDGE IS LOCATED W OF THE FRONT AND IS EXPECTED TO PROVIDE LIGHT EASTERLY FLOW THROUGH LATE FRIDAY AS THE FRONT MOVES NE OF 30N68W. FARTHER EAST...AN UPPER LEVEL RIDGE ENCOMPASSES A LARGE PORTION OF THE CENTRAL ATLC BETWEEN 35W-60W THAT SUPPORTS A SURFACE RIDGE EXTENDING FROM 40N44W TO 25N65W. ON THE SOUTHERN PERIPHERY OF THE RIDGE...A SHEAR LINE IS ANALYZED FROM 18N52W TO 21N61W AS MOISTURE ASSOCIATED WITH THE TAIL END OF A REMNANT FRONTAL BOUNDARY DRIFTS WESTWARD PROVIDING ISOLATED SHOWERS FROM 16N-23N BETWEEN 52W-65W. FARTHER EAST...THE SOURCE OF THIS REMNANT FRONTAL BOUNDARY REMAINS AS A RAPIDLY DISSIPATING 1013 MB LOW CENTERED NEAR 25N32W. ISOLATED SHOWERS ARE OCCURRING FROM 20N-27N BETWEEN 28W-34W. FINALLY...A COLD FRONT IS DRAPED OVER THE NE ATLC WATERS ENTERING THE DISCUSSION AREA NEAR 32N33W AND EXTENDING WESTWARD TO 31N47W. WHILE NO SIGNIFICANT DEEP CONVECTION IS NOTED ON SATELLITE IMAGERY ALONG THE FRONT...POSSIBLE ISOLATED SHOWERS ARE WITHIN 90 NM EITHER SIDE OF THE FRONT. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ HUFFMAN