000 AXNT20 KNHC 162330 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 805 PM EDT TUE APR 16 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 2245 UTC. ...THE ITCZ/THE MONSOON TROUGH... THE MONSOON TROUGH PASSES THROUGH COASTAL SENEGAL NEAR 12N17W TO 6N18W 4N22W. THE ITCZ EXTENDS ALONG 4N22W TO 2N30W. SCATTERED MODERATE CONVECTION IS FROM 4N-6N BETWEEN 19W-22W. ISOLATED MODERATE CONVECTION IS FROM 3N-4N BETWEEN 26W-33W. ...DISCUSSION... THE GULF OF MEXICO... MOSTLY FAIR CONDITIONS ARE ACROSS MUCH OF THE GULF OF MEXICO THIS EVENING ASSOCIATED WITH DRY AIR AND SUBSIDENCE ALOFT AROUND AN UPPER LEVEL RIDGE WITH AXIS ALONG 87W. SOME UPPER LEVEL MOISTURE IS STREAMING OVER THE NW GULF AROUND THE WEST SIDE OF THE UPPER RIDGE. ONLY A FEW SHOWERS ARE NOTED OVER COASTAL MISSISSIPPI WITH SOME HEAVY STORMS OVER SW FLORIDA. AT THE SURFACE...BROAD RIDGING EXTENDS FROM A HIGH CENTER OVER THE NW ATLC PROVIDING EAST TO SOUTHEAST WINDS RANGING FROM 10-20 KT. LITTLE CHANGE IS EXPECTED EXCEPT A POSSIBLE INCREASE IN WIND SPEED ACROSS THE WESTERN GULF AHEAD OF A COLD FRONT EXPECTED TO MOVE OFF THE TEXAS COAST LATE THURSDAY/EARLY FRIDAY. THE CARIBBEAN SEA... THE UPPER LEVEL RIDGE OVER THE GULF OF MEXICO ALSO COVERS THE CARIBBEAN CENTERED IN THE SW PORTION NEAR 13N80W. DRY AIR ALOFT ALSO SPREADS ACROSS THE AREA PROVIDING MOSTLY CLEAR SKIES THROUGHOUT. A FEW ISOLATED SHOWERS/THUNDERSTORMS HAVE POPPED UP ALONG THE SOUTHERN COASTS OF CUBA...HISPANIOLA...AND ACROSS MUCH OF PUERTO RICO. MORE SCATTERED ACTIVITY IS ACROSS THE NORTHERN LEEWARD ISLANDS ASSOCIATED WITH A SMALL AREA OF LOW-LEVEL MOISTURE PRESENT IN TOTAL PRECIPITABLE WATER IMAGERY. TRADEWIND FLOW OF 15-20 KT BLOWS THROUGHOUT MUCH OF THE EASTERN AND CENTRAL CARIBBEAN REACHING 25 KT NEAR THE COAST OF COLOMBIA. LITTLE CHANGE IS EXPECTED OVER THE NEXT 24 HOURS. SHOWERS/POSSIBLE THUNDERSTORMS ARE LIKELY TO REMAIN ACROSS THE NORTHERN LEEWARD ISLANDS. THE ATLANTIC OCEAN... THE UPPER LEVEL RIDGE ACROSS THE GULF OF MEXICO CONTINUES UP THE EASTERN SEABOARD. AN UPPER LEVEL TROUGH TO THE EAST IS SUPPORTING A PAIR OF 1019 MB SURFACE LOWS NEAR 30N75W AND 30N67W. THE LOWS ARE CONNECTED BY A STATIONARY FRONT. A COLD FRONT CONTINUES FROM THE WESTWARD LOW TO NEAR 27N80W. A COLD FRONT ALSO CONTINUES EAST OF THE EASTWARD LOW CONNECTING INTO A DEEP LOW-PRESSURE SYSTEM IN THE NORTH CENTRAL ATLC. THE COLD FRONT EXTENDS ALONG 30N65W 28N51W 32N37W CONTINUING OUT OF THE DISCUSSION AREA. SCATTERED SHOWERS ARE ALONG THE COLD FRONT BOUNDARY EAST OF THE TWO LOW CENTERS. SIMILAR ACTIVITY IS ALSO SE OF THE EASTWARD LOW FROM 26N-30N BETWEEN 60W-67W. NO SHOWER ACTIVITY IS NEAR THE WESTWARD LOW. BOTH LOW CENTERS ARE EXPECTED TO DISSIPATE WITHIN THE NEXT 24 HOURS AS THE FRONTAL BOUNDARY GRADUALLY DISSIPATES AS WELL. AN AREA OF SHOWERS AND THUNDERSTORMS IS NEAR THE NORTHERN LEEWARD ISLANDS FROM 14N-20N BETWEEN 58W-62W ASSOCIATED WITH AN AREA OF ENHANCED LOW-LEVEL MOISTURE PRESENT IN TOTAL PRECIPITABLE WATER IMAGERY. THE REMAINDER OF THE EAST ATLC IS COVERED BY WEAK SURFACE RIDGING AROUND A PAIR OF 1021 MB SURFACE HIGHS NEAR 27N43W AND 29N31W. BROAD UPPER RIDGING ALONG 17W SUPPORTS THE SURFACE HIGH PRESSURE. THESE HIGH CENTERS WILL DISSIPATE AS THE COLD FRONT TO THE WEST MOVES EAST. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ WALTON