000 AXNT20 KNHC 311735 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 205 PM EDT SUN MAR 31 2013 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...WEATHER OBSERVATIONS...RADAR...AND METEOROLOGICAL ANALYSIS. BASED ON 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 1415 UTC. ...THE ITCZ/THE MONSOON TROUGH... THE MONSOON TROUGH EXTENDS THROUGH THE COAST OF GUINEA-BISSAU NEAR 12N16W INTO THE EASTERN TROPICAL ATLC ALONG 6N20W 3N22W. THE ITCZ BEGINS NEAR 3N22W AND CONTINUES ALONG 1N30W 1N40W 1S46W. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS FROM 2S- 2N BETWEEN 23W-30W...FROM EQ-4N BETWEEN 30W-42W...AND FROM 1N-3N BETWEEN 46W-52W. ...DISCUSSION... GULF OF MEXICO... SOUTHEAST TO SOUTH FLOW COVERS THE GULF OF MEXICO AROUND A SURFACE RIDGE ANCHORED IN THE WEST ATLC. CLEAR SKIES SPREAD ACROSS A GOOD PORTION OF THE BASIN DUE TO DRY AIR ALOFT COVERING THE SOUTHERN GULF AROUND THE BASE OF AN UPPER LEVEL TROUGH EXTENDING DOWN FLORIDA ALONG 81W. HOWEVER...UPPER LEVEL MOISTURE IS STREAMING AROUND AN UPPER LEVEL RIDGE MOVING INTO THE AREA ALONG 97W. AN AREA OF SHOWERS/THUNDERSTORMS IS IN THE NE CORNER FROM 28N-29N BETWEEN 83W-87W LIKELY DUE TO WIND SPEED CONVERGENCE. A RECENT ASCAT PASS INDICATES SOUTHERLY WINDS UP TO 20 KT JUST SOUTH OF THE AREA OF ACTIVITY WITH 10-15 KT WINDS TO THE NORTH. WINDS UP TO 15 KT COVER MUCH OF THE EASTERN GULF WITH 10-15 KT WINDS ACROSS THE WESTERN GULF. THE RIDGE WILL CONTINUE TO MOVE EAST ALLOWING RETURN FLOW TO INCREASE ACROSS THE GULF MID-WEEK BEFORE A COLD FRONT AND SURFACE LOW SWEEP THROUGH THE BASIN THROUGHOUT THE SECOND HALF OF THE WEEK. CARIBBEAN SEA... DRY AIR ALOFT AROUND THE BASE OF THE UPPER TROUGH EXTENDING DOWN FLORIDA AND INTO THE NW CARIBBEAN IS PROVIDING FAIR CONDITIONS ACROSS THE WESTERN CARIBBEAN. MODERATE DRY AIR ALSO COVERS THE CENTRAL AND EASTERN CARIBBEAN AROUND A BROAD UPPER LEVEL RIDGE COVERING MUCH OF THE CENTRAL AND EASTERN ATLC. THE DRY AIR IS MAINTAINING FAIR CONDITIONS ACROSS THE CENTRAL AND EASTERN AREAS EXCEPT FOR SOME MOISTURE REMAINING ACROSS THE NORTHERN ISLANDS. THIS MOISTURE REMAINS FROM AN OLD FRONTAL BOUNDARY/SHEAR AXIS THAT HAS NOW DISSIPATED. SCATTERED SHOWERS ARE FROM 16N-19N BETWEEN 63W-70W INCLUDING AREAS OF PUERTO RICO AND EASTERN HISPANIOLA. STRONG TRADEWIND FLOW OF 20-25 KT IS PRESENT ACROSS A LARGE AREA OF THE BASIN DUE TO THE INCREASED PRESSURE GRADIENT BETWEEN HIGH PRESSURE TO THE NORTH AND LOW PRESSURE OVER SOUTH AMERICA. WINDS REACH 30 KT OFF THE COAST OF COLOMBIA. MOISTURE WILL REMAIN OVER THE NORTHERN CARIBBEAN FOR AT LEAST THE NEXT DAY BEFORE LIFTING NORTH. LITTLE CHANGE IS EXPECTED ELSEWHERE ACROSS THE BASIN. ATLANTIC OCEAN... SURFACE RIDGING COVERS THE WEST ATLC INTO THE CENTRAL ATLC ANCHORED BY A 1026 MB HIGH NEAR 30N68W. THE RIDGE IS PROVIDING MOSTLY FAIR WEATHER ACROSS THIS AREA. THE RIDGE IS SUPPORTED BY AN UPPER LEVEL RIDGE ALONG 69W. A WEAK UPPER TROUGH IS TO THE EAST SUPPORTING A SURFACE TROUGH ALONG 32N55W 29N59W 27N63W. THE SURFACE TROUGH EXTENDS INTO THE SURFACE RIDGE. ISOLATED SHOWERS ARE WITHIN 150 NM EAST OF THE AXIS. A BROAD UPPER TROUGH NORTH OF THE DISCUSSION AREA SUPPORTS A WEAK COLD FRONT THAT STRETCHES ACROSS THE BASIN FROM THE NE SECTION NEAR 32N22W ALL THE WAY TO THE NE CARIBBEAN ALONG 24N36W 20N50W BECOMING STATIONARY TO 19N63W. ISOLATED SHOWERS ARE WITHIN 90 NM EAST OR SOUTH OF THE AXIS. A VERY BROAD UPPER RIDGE COVERS THE REMAINDER OF THE TROPICAL ATLC CENTERED NEAR 18N26W. A STRONG UPPER LEVEL JET IS ALONG THE NORTHERN PERIPHERY OF THE RIDGE REACHING UP TO 150 KT SOUTH OF THE AZORES ISLANDS. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ WALTON