000 AXNT20 KNHC 030528 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 205 AM EDT SUN MAY 03 2009 TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL AMERICA...GULF OF MEXICO...CARIBBEAN SEA...NORTHERN SECTIONS 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 0430 UTC. ...THE ITCZ... THE ITCZ AXIS EXTENDS FROM W AFRICA AT 05N08W TO THE EQUATOR AT 29W TO NE BRAZIL NEAR 04S38W. SCATTERED MODERATE TO ISOLATED STRONG CONVECTION CAN BE FOUND ALONG THE COAST OF BRAZIL FROM 05S TO 01S W OF 30W. ...DISCUSSION... GULF OF MEXICO... HIGH CLOUDS ON THE ON THE LEADING EDGE OF THE DEEP LAYER TROUGH MOVING THROUGH TEXAS ARE CURRENTLY PUSHING SOUTHEASTWARD INTO THE NW GULF OF MEXICO. ELSEWHERE...FAIR WEATHER AND SUBSIDENT CONDITIONS PREVAIL OVER THE REGION. THE QUIKSCAT PASS FROM 0048 UTC SHOWS SE WINDS ACROSS THE WESTERN GULF TO 25 KT. THIS STRONG SOUTHEASTERLY FLOW IS THE RESULT OF THE TIGHT PRESSURE GRADIENT BETWEEN THE WESTERN EDGE OF THE ATLC RIDGE WHICH EXTENDS INTO THE EASTERN GULF AND THE TROUGHING OVER THE SOUTHERN PLAINS. AS THIS TROUGH MOVES EASTWARD THROUGH THE SOUTHEASTERN U.S. OVER THE NEXT DAY OR TWO...LOOK FOR THE RIDGE AXIS TO RETREAT TO THE E SOMEWHAT...WEAKENING THE PRESSURE GRADIENT AND RESULTING WINDS OVER THE W GULF. CARIBBEAN SEA... UPPER LEVEL SOUTHWESTERLY FLOW ON THE WESTERN SIDE OF THE UPPER RIDGE OVER THE WESTERN AND CENTRAL CARIBBEAN IS TRANSPORTING UPPER LEVEL MOISTURE FROM THE EASTERN PACIFIC THROUGH CENTRAL AMERICA INTO THE WESTERN CARIBBEAN...WITH MULTILAYERED CLOUDINESS AND SOME ISOLATED SHOWERS FOUND OVER MUCH OF THE SW CARIBBEAN AND THE GULF OF HONDURAS. THE 2312 QUIKSCAT PASS REVEALED WINDS TO 25 KT OVER MUCH OF THE CENTRAL CARIBBEAN...WITH EVEN STRONGER WINDS IN THE ATLC PASSAGES. THESE STRONG WINDS ARE THE RESULT OF THE TIGHT PRESSURE GRADIENT BETWEEN THE RIDGE AXIS CENTERED FROM BERMUDA THROUGH CENTRAL FLORIDA AND TROUGHING BOTH TO THE SOUTH AND THE EAST. THE TROUGHING TO THE SOUTH IS ASSOCIATED WITH CLIMATOLOGICAL LOW PRESSURE CENTERED NEAR THE COAST OF COLOMBIA WHILE THE TROUGHING TO THE EAST IS ATTRIBUTED TO THE DEEP LAYER TROUGH BEGINNING TO BREAK DOWN OVER THE NORTHERN LESSER ANTILLES. MIMIC-TPW IMAGERY SHOWS LOW TO MID LEVEL MOISTURE CONVERGENCE OVER THE LESSER ANTILLES DUE TO THE TROUGH. MOSTLY ISOLATED SHOWERS CAN BE SEEN ON THE GUADALOUPE RADAR...WITH A MORE ORGANIZED BAND NEAR BARBADOS EXTENDING NORTHEASTWARD INTO THE ATLC. THE LOW LEVEL TROUGH IS EXPECTED TO CONTINUE MOVING NORTHWESTWARD INTO THE GREATER ANTILLES OVER THE NEXT DAY OR TWO...SHIFTING THE MOISTURE POOL AND THE GREATEST CHANCE FOR SHOWER ACTIVITY WESTWARD WITH IT. ATLANTIC OCEAN... A WEAK UPPER TROUGH CURRENTLY LIES FROM BERMUDA JUST NORTH OF THE BAHAMAS INTO FLORIDA...CORRESPONDING WITH THE SAME POSITION AS THE RIDGE AXIS AS THE SURFACE. MOSTLY DRY AIR ALOFT IN THIS REGION HAS BROUGHT FAIR WEATHER HERE. THERE IS NO NOTABLE SHOWER ACTIVITY ON BAHAMIAN...BERMUDAN...OR U.S. RADARS IN THIS REGION AT THE MOMENT. THE 2308 UTC QUIKSCAT PASS SHOWS THE STRONGEST WINDS IN THE WESTERN ATLC CAN BE FOUND ON THE NORTHERN EDGE OF THE SURFACE TROUGH ALONG 62W FROM 22N TO 27N...WITH EASTERLY WINDS TO 25 KT IN THIS AREA WHERE THE PRESSURE GRADIENT BETWEEN THIS TROUGH AND THE RIDGE AXIS IS GREATEST. THE LOW LEVEL TROUGH IS EXPECTED TO CONTINUE WESTWARD TOWARD THE TURKS AND CAICOS OVER THE NEXT DAY OR TWO...TRANSPORTING LOW LEVEL MOISTURE AND A GREATER CHANCE FOR SHOWER ACTIVITY ALONG WITH IT. ELSEWHERE IN THE TROPICAL ATLC...CONVECTION ALONG THE ITCZ IS STRONGEST NEAR THE COAST OF BRAZIL FROM 05S TO 01S W OF 30W...COINCIDING WITH A REGION OF MODERATE UPPER LEVEL DIFFLUENCE. THE 1948 AND 2130 UTC QUIKSCAT PASSES SHOW THE STRONGEST WINDS IN THE TROPICAL E ATLC BETWEEN 15N AND 25N E OF 35W TO THE COAST OF AFRICA WHERE THE PRESSURE GRADIENT HAS BEEN TIGHTENED ON THE SOUTHERN EDGE OF THE HIGH PRESSURE RIDGE DUE TO A DEEP LAYER LOW CENTERED N OF THE AREA...WITH AN ASSOCIATED SURFACE COLD FRONT EXTENDING FROM 32N38W TO 25N41W. THE TROUGHING AT THE SURFACE IS EXPECTED TO WEAKEN HERE...ALONG WITH THE WINDS...OVER THE NEXT DAY OR TWO. $$ SCHAUER CLARK