000 AXNT20 KNHC 222339 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 805 PM EDT FRI APR 22 2011 TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL AMERICA...GULF OF MEXICO...CARIBBEAN SEA...NORTHERN SECTION OF SOUTH AMERICA...AND ATLANTIC OCEAN TO THE AFRICAN COAST FROM THE EQUATOR TO 32N. THE FOLLOWING INFORMATION IS BASED ON SATELLITE IMAGERY...METEOROLOGICAL ANALYSIS...WEATHER OBSERVATIONS...AND RADAR. BASED ON 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 2300 UTC. ...SPECIAL FEATURE... A 1008 MB NON-TROPICAL LOW CONTINUES TO SPIN ABOUT 430 NM S OF BERMUDA NEAR 27N64W. SHOWER ACTIVITY HAS NOT INCREASED FROM EARLIER TODAY WITH A SMALL AREA OF SHOWERS/POSSIBLE THUNDERSTORMS S OF THE CENTER FROM 25N-26N BETWEEN 64W-65W...AND SCATTERED SHOWERS/ISOLATED THUNDERSTORMS WITHIN 75 NM N AND E OF A SURFACE TROUGH EXTENDING FROM THE LOW CENTER ALONG 27N62W 25N60W 21N62W 19N65W. E WINDS UP TO 30 KTS ARE N OF THE SYSTEM WITH 20-25 KT WINDS ELSEWHERE AROUND THE LOW CENTER AND TROUGH. WATER VAPOR IMAGERY INDICATES A DRY SLOT OF AIR BEING SUCKED AROUND THE SRN SEMI-CIRCLE OF THE STORM. THIS DRY AIR INTRUSION ALONG WITH UNFAVORABLE UPPER LEVEL WINDS ARE EXPECTED TO HINDER FURTHER DEVELOPMENT. THE SYSTEM IS CURRENTLY MOVING WSW AT 9KT. A GENERAL SW MOTION IS EXPECTED OVER THE NEXT COUPLE OF DAYS. ...THE ITCZ... THE ITCZ AXIS EXTENDS FROM SRN LIBERIA NEAR 5N8W CONTINUING SW AND CROSSING THE EQUATOR NEAR 15W ALONG 4S25W AND SKIRTING THE BRAZILIAN COAST ALONG 3S40W EQ50W. ISOLATED MODERATE/STRONG CONVECTION IS FROM 4N-6N BETWEEN 10W-14W...AND FROM EQ-3N BETWEEN 22W-27W. ...DISCUSSION... THE GULF OF MEXICO... A DRY AND STABLE AIRMASS SITS ACROSS THE GULF OF MEXICO AROUND AN UPPER LEVEL RIDGE EXTENDING FROM THE CENTRAL GULF ACROSS THE ERN CONUS. THE DRY AIR IS SUPPORTING FAIR SURFACE CONDITIONS WITH MOSTLY CLEAR SKIES BASIN-WIDE. SE-S RETURN FLOW OF 15-20 KTS IS EVIDENT ACROSS MUCH OF THE WRN HALF OF THE BASIN WITH THE STRONGEST WINDS ALONG THE TEXAS COAST. EXPECT LITTLE CHANGE OVER THE NEXT SEVERAL DAYS. THE CARIBBEAN SEA... MUCH OF THE CARIBBEAN IS EXPERIENCING MOSTLY FAIR WEATHER THIS EVENING WITH LIGHT TO MODERATE WINDS ACROSS MUCH OF THE BASIN. A SURFACE TROUGH ASSOCIATED WITH A LOW PRESSURE SYSTEM IN THE ATLC EXTENDS SWD TO JUST N OF PUERTO RICO AND PRODUCING SCATTERED SHOWERS AROUND THE SE SIDE OF THE ISLAND AND ACROSS THE VIRGIN ISLANDS. POSSIBLE ISOLATED SHOWERS ARE ALSO EMBEDDED IN THE ELY TRADEWIND FLOW. ALOFT...UNIFORM SWLY FLOW DOMINATES THE BASIN DRAWING MOISTURE ACROSS THE AREA SUPPORTING HIGH CLOUDS. TOTAL PRECIPITABLE WATER IMAGERY INDICATES AN AREA OF ENHANCED MOISTURE MOVING INTO THE SE CARIBBEAN WHICH WILL INCREASE THE LIKELIHOOD OF SHOWER ACTIVITY IN THAT PORTION OF THE BASIN. THIS AREA OF MOISTURE IS EXPECTED TO DRIFT W. ALSO EXPECT POSSIBLE SHOWER ACTIVITY TO INCREASE ACROSS THE NRN ISLANDS AS THE LOW PRESSURE SYSTEM IN THE ATLC MOVES SW. THE ATLANTIC OCEAN... A DISSIPATING COLD FRONT CLIPS THE NW PORTION OF THE BASIN ALONG 31N68W 29N73W 30N76W. ISOLATED SHOWERS ARE N OF THE BOUNDARY. THIS SYSTEM IS ASSOCIATED WITH AN UPPER LEVEL TROUGH N OF THE AREA THAT IS QUICKLY MOVING E...AS AN UPPER RIDGE BUILDS INTO THE FAR W ATLC. A CUT-OFF UPPER LEVEL LOW IS S OF THE UPPER TROUGH NEAR 26N64W AND SUPPORTS A LOW PRESSURE SYSTEM CENTERED ALMOST DIRECTLY BELOW IT. SEE SPECIAL FEATURES ABOVE FOR MORE DETAILS ON THIS SYSTEM. AN AREA OF SCATTERED SHOWERS/POSSIBLE THUNDERSTORMS IS FARTHER E OF THE LOW FROM 21N-30N BETWEEN 52W-57W. THE REMAINDER OF THE BASIN IS DOMINATED BY A BROAD SURFACE RIDGE ANCHORED BY A 1028 MB HIGH NEAR 34N35W PROVIDING FAIR WEATHER E OF 50W. ALOFT...AN UPPER LEVEL RIDGE DOMINATES THE E ATLC WITH AXIS ACROSS THE AZORES ISLANDS. BROAD UPPER RIDGING ALSO DOMINATES THE TROPICAL ATLC. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ WALTON