000 AXNT20 KNHC 241037 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 805 AM EDT TUE APR 24 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 1015 UTC. ...ITCZ/MONSOON TROUGH... THE MONSOON TROUGH EXTENDS ACROSS W AFRICA INTO THE E TROPICAL ATLC NEAR 12N16W ALONG 7N16W TO 4N17W WHERE THE ITCZ CONTINUES S OF THE EQUATOR NEAR 23W. SMALL CLUSTERS OF SCATTERED MODERATE/ ISOLATED STRONG CONVECTION ARE FROM 2N-4N E OF 1W ACROSS THE PRIME MERIDIAN AND FROM 4N TO THE EQUATOR BETWEEN 16W-27W. ...DISCUSSION... GULF OF MEXICO... BROAD UPPER TROUGH CONTINUES TO MOVE FURTHER INTO THE W ATLC WITH A SURFACE TROUGH AT 24/0900 UTC EXTENDING FROM THE ATLC ACROSS THE NW CARIBBEAN AND THE N YUCATAN PENINSULA NEAR 21N89W TO 22 93W IN THE GULF. STRONG SUBSIDENCE A DRY STABLE AIR DOMINATE THE GULF. A WEAK SURFACE RIDGE REMAINS OVER THE W GULF ANCHORED BY A 1019 MB HIGH NEAR ALONG THE COAST OF LOUISIANA NEAR 30N93W. COLD AIR STRATOCUMULUS CLOUDS COVER THE SE GULF S OF 28N E OF 90W LEAVING THE REMAINDER OF THE GULF WITH CLEAR SKIES AGAIN THIS MORNING. THE SURFACE HIGH WILL SHIFT SE OVER THE NW GULF THROUGH TONIGHT THEN MOVE E TO NEAR TAMPA BAY WED NIGHT AND OUT OF THE GULF THU WITH A RIDGE EXTENDING W TO THE TEXAS COAST THROUGH SAT. THE COMBINATION OF THE RIDGE AND DEEPENING LOW PRESSURE IN THE SOUTHERN PLAINS WILL ALLOW FOR SOUTHERLY RETURN FLOW TO DEVELOP OVER THE FAR W GULF BEGINNING TONIGHT AND SPREAD E ACROSS MUCH OF THE AREA BY FRI WITH LITTLE CHANGE INTO SAT. CARIBBEAN SEA... THE UPPER TROUGH OVER THE GULF OF MEXICO AND W ATLC DIPS S OVER THE FAR NW CARIBBEAN. A SURFACE TROUGH AT 24/0900 UTC EXTENDS FROM THE W ATLC ACROSS CUBA NEAR SANTA CLARA OVER THE CAYMAN ISLANDS TO OVER THE N YUCATAN PENINSULA NEAR 21N88W THEN INTO THE GULF OF MEXICO WITH ISOLATED SHOWERS WITHIN 45 NM S OF THE TROUGH. A SECOND SURFACE TROUGH IS TO THE E EXTENDING FROM THE W/CENTRAL ATLC ACROSS HISPANIOLA ALONG 19N71W 16N73W TO 12N75W GENERATING SCATTERED SHOWERS AND POSSIBLE ISOLATED THUNDERSTORMS ACROSS THE CENTRAL CARIBBEAN BETWEEN 70W-78W. A BROAD UPPER RIDGE DOMINATES THE REMAINDER OF THE CARIBBEAN BASIN ANCHORED OVER SE VENEZUELA. THE CONVERGENCE OF UPPER AND LOWER LEVEL FLOW IS GENERATING SCATTERED SHOWERS/ISOLATED THUNDERSTORMS INLAND AND WITHIN 90 NM OF THE COAST OF COLOMBIA AND PANAMA BETWEEN 75W-80W WITH SCATTERED SHOWERS WITHIN 90 NM ALONG THE COAST OF COSTA RICA. THE SURFACE TROUGH WILL DRIFT W REACHING A POSITION FROM HAITI TO THE CENTRAL CARIBBEAN BY WED EVENING AND FROM E CUBA TO THE CENTRAL CARIBBEAN THU BEFORE IT BECOMES DIFFUSE. FRESH NORTHERLY WINDS WILL PREVAIL W OF THE TROUGH WITH MODERATE TRADE WINDS ELSEWHERE. A W ATLC SURFACE RIDGE BUILDS E WED AFTERNOON THROUGH FRI. ATLANTIC OCEAN... THE BROAD UPPER TROUGH OVER THE GULF OF MEXICO IS MOVING FURTHER OVER THE W ATLC STILL SUPPORTING A COLD FRONT THAT ENTERS THE W ATLC NEAR 32N67W EXTENDING TO 27N69W WHERE IT BECOMES STATIONARY ALONG 24N71W THROUGH THE BAHAMA ISLANDS TO OVER CUBA NEAR 20N77W. STRONG SUBSIDENCE AND DRY STABLE AIR ARE W OF THE FRONT THUS LIMITING ANY SHOWER ACTIVITY. A SURFACE TROUGH IS TRAILING THE FRONT EXTENDING FROM 27N75W ACROSS THE BAHAMA ISLANDS TO OVER CUBA NEAR SANTA CLARA WITH ISOLATED SHOWERS WITHIN 45 NM EITHER SIDE OF THE TROUGH. A SECOND SURFACE TROUGH IS TO THE E OF THE FRONT EXTENDING FROM 27N63W ALONG 23N66W ACROSS HISPANIOLA INTO THE CARIBBEAN NEAR 19N71W WITH SCATTERED SHOWERS/THUNDERSTORMS WITHIN 75 NM EITHER SIDE OF THE TROUGH AXIS BETWEEN 21N-25N AND WITH SCATTERED SHOWERS AND POSSIBLE ISOLATED THUNDERSTORMS WITHIN 150 NM E AND WITHIN 60 NM W OF THE REMINDER OF THE TROUGH. THE UPPER RIDGE OVER THE CARIBBEAN EXTENDS A RIDGE AXIS ACROSS THE PUERTO RICO/VIRGIN ISLANDS TO BEYOND 32N58W FURTHER ENHANCING THE ACTIVITY ASSOCIATED WITH THE SURFACE TROUGH. AN ELONGATED UPPER LOW IS IN THE CENTRAL ATLC EXTENDING FROM BEYOND 33N47W TO 25N42W SUPPORTING A SURFACE TROUGH THAT EXTENDS FROM 34N45W ALONG 30N46W TO 26N42W WITH SCATTERED SHOWERS/ISOLATED THUNDERSTORMS E OF THE TROUGH AXIS TO 42W. A BROAD SURFACE RIDGE DOMINATES THE ATLC W OF 60W WITH A WEAKNESS IN THE IMMEDIATE VICINITY OF THE ABOVE SURFACE TROUGH AND ANCHORED BY A 1029 MB HIGH JUST S OF THE AZORES. THIS IS GIVING THE REMAINDER OF THE ATLC FAIR WEATHER THIS MORNING. THE COLD FRONT WILL GRADUALLY WEAKEN AS IT REACHES A POSITION FROM NEAR BERMUDA TO HISPANIOLA WED. A SURFACE TROUGH WILL EXTEND FROM W OF BERMUDA TO E CUBA BY EARLY TONIGHT THEN MERGE WITH THE COLD FRONT WED EVENING FROM JUST S OF BERMUDA TO BETWEEN PUERTO RICO AND BERMUDA WHERE IT WILL BECOME STATIONARY TO HISPANIOLA. THE S PORTION OF THE FRONT WILL THEN MOVE BACK W ACROSS THE S WATERS AS A TROUGH WED NIGHT. IT WILL REACH E CUBA THU THEN BECOME DIFFUSE NEAR CENTRAL CUBA FRI. HIGH PRESSURE WILL SHIFT E FROM FLORIDA ACROSS THE W ATLC WED AND THU AND TO OVER THE N/CENTRAL ATLC FRI. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ PAW