000 AXNT20 KNHC 221746 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 205 PM EDT TUE MAY 22 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 1700 UTC. ...SPECIAL FEATURES... AS OF 1500 UTC...TROPICAL DEPRESSION ALBERTO WAS DOWNGRADED TO A POST-TROPICAL LOW. THE LOW IS CENTERED AT 33.1N 74.0W...OR ABOUT 150 NM SSE OF CAPE HATTERAS NORTH CAROLINA...AND ABOUT 255 NM SSE OF NORFOLK VIRGINIA. IT IS MOVING NE AT 15 KTS WITH MAXIMUM SUSTAINED WIND SPEEDS OF 30 KTS AND GUSTS TO 40 KTS. THE MINIMUM SEA LEVEL PRESSURE IS 1008 MB. STRONG SHEAR WILL CONTINUE TO WEAKEN THE SYSTEM WHICH CURRENTLY ONLY HAS A SMALL AREA OF SHOWERS/THUNDERSTORMS ASSOCIATED WITH IT WITHIN 120 NM NE OF THE CENTER. PLEASE READ THE LATEST NHC FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMAT1/ WTNT21 KNHC...AND THE PUBLIC BULLETIN MIATCPAT1/WTNT31 KNHC FOR MORE DETAILS. ...TROPICAL WAVES... A TROPICAL WAVE IS ALONG 13N24W TO 3N26W MOVING W NEAR 12KT. THE WAVE COINCIDES WITH A SURGE OF DEEP LAYER MOISTURE PRESENT IN TOTAL PRECIPITABLE WATER IMAGERY. DUST ENHANCEMENT IMAGERY ALSO INDICATES THAT THERE IS A CLEARING OF THE DUST SURROUNDING THE WAVE. SCATTERED MODERATE CONVECTION IS FROM 3N-5N BETWEEN 26W-28W. A TROPICAL WAVE EXTENDS FROM 15N46W TO 7N49W MOVING W NEAR 10-15 KTS. THIS WAVE ALSO COINCIDES WITH A NWD SURGE IN DEEP LAYER MOISTURE EVIDENT IN TOTAL PRECIPITABLE WATER IMAGERY. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS RESTRICTED TO THE ITCZ REGION FROM 8N-10N BETWEEN 47W-50W. ...THE ITCZ/THE MONSOON TROUGH... THE MONSOON TROUGH EXTENDS ACROSS W AFRICA AND ENDS AT THE COAST OF SENEGAL AT 17N16W. THE ITCZ CONTINUES ON THE W SIDE OF THE TROPICAL WAVE NEAR THE COAST OF AFRICA ALONG 4N27W 5N37W 8N50W 7N59W. SCATTERED MODERATE CONVECTION IS WITHIN 50 NM N OF THE AXIS BETWEEN 30W-34W...AND WITHIN 100 NM N OF THE AXIS BETWEEN 51W-56W. ...DISCUSSION... THE GULF OF MEXICO... DRY AIR ALOFT AROUND THE BASE OF AN UPPER LEVEL TROUGH CENTERED OVER TENNESSEE IS PROVIDING FAIR CONDITIONS ACROSS MUCH OF THE GULF OF MEXICO. THE UPPER TROUGH SUPPORTS A WEAK SURFACE TROUGH EXTENDING FROM NE FLORIDA NEAR 31N82 ALONG 29N87W TO SW LOUISIANA AT 30N93W SUPPORTING A FEW CLUSTERS OF SHOWERS/THUNDERSTORMS ALONG THE AXIS...AS OF 1500 UTC. A WEAK SURFACE RIDGE AROUND A 1017 MB HIGH NEAR 26N93W IS PRODUCING LIGHT ANTI-CYCLONIC FLOW IN THE NW GULF WITH STRONG NE WINDS ACROSS THE SW GULF. TOTAL PRECIPITABLE WATER IMAGERY INDICATES SOME HIGHER MOISTURE VALUES ACROSS THE SE GULF ASSOCIATED WITH AN AREA OF LOW PRESSURE IN THE NW CARIBBEAN. NO SHOWERS/THUNDERSTORMS ARE CURRENTLY IMPACTING THIS AREA...BUT COULD BE POSSIBLE OVER THE NEXT FEW DAYS AS THIS SYSTEM MOVES NE. SURFACE RIDGING WILL CONTINUE OVER THE REMAINDER OF THE BASIN FOR THE NEXT 24 HOURS PROVIDING FAIR WEATHER. THE CARIBBEAN SEA... BROAD CYCLONIC SURFACE FLOW COVERS THE NW CARIBBEAN AROUND A 1009 MB LOW NEAR 18N86W. A SURFACE TROUGH EXTENDS THROUGH THE LOW CENTER FROM NW HONDURAS AT 16N87W TOWARDS WRN CUBA ALONG 20N83W 24N82W. THIS AREA ALSO LIES UNDERNEATH DIFFLUENCE ALOFT BETWEEN AN UPPER LEVEL TROUGH OVER THE GULF OF MEXICO AND AN UPPER LEVEL RIDGE EXTENDING FROM NICARAGUA ACROSS HISPANIOLA AND INTO THE W ATLC. THIS PATTERN IS HELPING PRODUCE NUMEROUS SHOWERS/THUNDERSTORMS FROM 14N-18N BETWEEN 78W-82W...AND FROM 18N-22N BETWEEN 79W-83W. SCATTERED SHOWERS/ISOLATED THUNDERSTORMS ARE ALSO ACROSS THE AREA FROM 10N-22N BETWEEN 78W-86W. THIS SYSTEM IS EXPECTED TO MOVE NE OVER THE NEXT SEVERAL DAYS. THE ERN CARIBBEAN IS EXPERIENCING MOSTLY FAIR WEATHER DUE TO DRY AIR ALOFT AROUND THE E SIDE OF THE AFOREMENTIONED UPPER LEVEL RIDGE. TRADEWIND FLOW OF 15-20 KTS COVERS MUCH OF THE BASIN BESIDES NEAR THE AREA OF LOW PRESSURE IN THE WRN GULF. EXPECT MOIST CONDITIONS TO REMAIN OVER THE WRN GULF FOR THE NEXT SEVERAL DAYS WITH FAIR CONDITIONS OVER THE ERN CARIBBEAN. THE ATLANTIC OCEAN... DIFFLUENCE ALOFT BETWEEN AN UPPER LEVEL TROUGH OVER THE SE CONUS AND AN UPPER LEVEL RIDGE EXTENDING FROM THE CARIBBEAN ACROSS HISPANIOLA TO 37N51W IS SUPPORTING SCATTERED SHOWERS/ISOLATED THUNDERSTORMS N OF CUBA TO 26N BETWEEN 73W-80W...AND N OF 26N BETWEEN 61W-75W. THE UPPER RIDGE ALSO SUPPORTS A BROAD SURFACE RIDGE AROUND A 1028 MB HIGH NEAR 32N54W WHICH IS PROVIDING FAIR CONDITIONS ACROSS THE CENTRAL ATLC. AN UPPER LEVEL TROUGH EXTENDS FROM 31N38W TO 16N58W WHILE AN UPPER LEVEL RIDGE COVERS THE TROPICAL ERN ATLC CENTERED NEAR 15N28W. VISIBLE SATELLITE IMAGERY ALONG WITH GOES-R DUST ENHANCEMENT IMAGERY INDICATES THAT AN AREA OF DUST EXTENDS FROM THE COAST OF AFRICA TO 40W WITH CLEARING AROUND THE TROPICAL WAVE NEAR THE COAST OF AFRICA. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ WALTON