000 AXNT20 KNHC 102340 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 805 PM EDT TUE APR 10 2012 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 2300 UTC. ...THE ITCZ/THE MONSOON TROUGH... THE MONSOON TROUGH EXTENDS ACROSS W AFRICA TO THE COAST OF GUINEA-BISSAU AT 12N16W TO 3N21W. THE ITCZ CONTINUES FROM 3N21W ALONG 1N30W CROSSING THE EQUATOR AT 36W TO THE COAST OF BRAZIL AT 3S40W. SCATTERED MODERATE/ISOLATED STRONG CONVECTION SI S OF 7N CROSSING THE EQUATOR TO 7S BETWEEN 27W-42W. ...DISCUSSION... THE GULF OF MEXICO... MOSTLY DRY AIR IN MAINLY W-NW FLOW ALOFT COVERS THE GULF OF MEXICO THIS EVENING AROUND THE E SIDE OF AN UPPER LEVEL RIDGE COVERING THE WRN CONUS. THE UPPER RIDGE SUPPORTS A WEAK SURFACE RIDGE ACROSS THE NRN GULF AROUND A 1021 MB HIGH S OF LOUISIANA AT 29N92W. LIGHT ANTI-CYCLONIC FLOW IS AROUND THE HIGH CENTER. A SURFACE TROUGH IN THE WRN GULF ALONG 26N95W TO 21N92W IS SUPPORTING ISOLATED SHOWERS WITHIN 30 NM EITHER SIDE OF THE AXIS. ELSEWHERE...SKIES ARE MOSTLY CLEAR WITH A FEW PATCHES OF CLOUDS NEAR THE YUCATAN CHANNEL. EXPECT THE SURFACE TROUGH TO CONTINUE TO DRIFT W AND DISSIPATE AS SURFACE RIDGING REMAINS OVER THE NRN GULF. A WEAK FRONT IS ALSO EXPECTED TO MOVE THROUGH THE NE GULF BEGINNING WEDNESDAY BRINGING SHOWERS AND POSSIBLE THUNDERSTORMS. THE CARIBBEAN SEA... DRY AIR ALOFT IN ZONAL WLY FLOW IS PROVIDING FAIR CONDITIONS ACROSS MUCH OF THE CARIBBEAN WATERS. HOWEVER...A SURFACE TROUGH EXTENDS ACROSS THE CENTRAL CARIBBEAN FROM N OF HISPANIOLA AT 22N69W TO NE COLOMBIA AT 12N72W. AN AREA OF LOW-LEVEL MOISTURE ALSO COVERS THE NRN CARIBBEAN AREA. THE COMBINATION OF THESE TWO FACTORS IS HELPING PRODUCE SCATTERED SHOWERS/ISOLATED THUNDERSTORMS N OF 17N BETWEEN 65W-78W...INCLUDING PUERTO RICO...HISPANIOLA...JAMAICA...AND ERN CUBA. SCATTERED SHOWERS ARE ALSO NOTED OVER ERN HONDURAS AND NICARAGUA. THE REMAINDER OF THE AREA IS UNDER TRADEWIND FLOW OF 10-15 KTS WITH MOSTLY CLEAR SKIES. EXPECT THE SURFACE TROUGH TO REMAIN SOMEWHAT STATIONARY AND EVENTUALLY LIFT N. ENHANCED LOW-LEVEL MOISTURE WILL ALSO REMAIN OVER THE NRN CARIBBEAN INCREASING THE CHANGE FOR RAINFALL ACROSS THE NRN ISLANDS. THE ATLANTIC OCEAN... A LONGWAVE UPPER TROUGH COVERS THE W ATLC SUPPORTING A STATIONARY FRONT N OF THE DISCUSSION AREA. THE UPPER TROUGH ALSO SUPPORTS A SECOND STATIONARY FRONT FARTHER E ALONG 32N55W TO 26N58W WHERE IT LIFTS N AS A DISSIPATING WARM FRONT TO 23N62W. ISOLATED SHOWERS ARE WITHIN 30 NM EITHER SIDE OF THE AXIS WITH STRONGER ACTIVITY N OF THE DISCUSSION AREA. A SURFACE TROUGH EXTENDING FROM THE CARIBBEAN ACROSS HISPANIOLA TO 22N69W IS ALSO HELPING PRODUCE SCATTERED SHOWERS/ISOLATED THUNDERSTORMS BETWEEN THE WARM FRONT AND THE TROUGH FROM 19N-24N BETWEEN 61W-69W. WEAK SURFACE RIDGING EXTENDING FROM A 1023 MB HIGH AT 33N59W IS PROVIDING FAIR CONDITIONS BETWEEN THE TWO STATIONARY FRONTS ACROSS THE W ATLC. A BROAD UPPER LEVEL RIDGE COVERS MUCH OF THE CENTRAL ATLC ALONG 40W SUPPORTING A 1030 MB SURFACE HIGH AT 37N38W. THE SURFACE RIDGE IS PROVIDING FAIR CONDITIONS ACROSS MUCH OF THE CENTRAL AND ERN ATLC. A NARROW UPPER LEVEL TROUGH COVERS THE FAR ERN ATLC FROM PORTUGAL ACROSS THE MADEIRA ISLANDS TO 20N29W. THIS UPPER TROUGH SUPPORTS A WEAK 1015 MB SURFACE LOW SPINNING NEAR 27N26W. ONLY A SMALL AREA OF SCATTERED SHOWERS ARE E OF THE CENTER FROM 25N-29N BETWEEN 20W-23W. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ WALTON