000 AXNT20 KNHC 211144 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 805 AM EDT SUN APR 21 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 1045 UTC. ...ITCZ/MONSOON TROUGH... THE MONSOON TROUGH EXTENDS ACROSS THE COAST OF GUINEA NEAR 10N14W TO 2N23W. THE ITCZ BEGINS FROM 2N23W AND CONTINUES ALONG EQ39W 1S46W. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS FROM 1N-6N BETWEEN 11W-23W. ...DISCUSSION... GULF OF MEXICO... A BROAD UPPER LEVEL TROUGH COVERS THE MAJORITY OF THE GULF OF MEXICO WITH AXIS SHIFTING EAST AND CURRENTLY EXTENDING ALONG 83W. THE UPPER TROUGH CONTINUES TO SUPPORT A STATIONARY FRONT THAT EXTENDS FROM SOUTH FLORIDA NEAR 26N80W TO 24N89W 19N91W...AS OF 0900 UTC. MOST OF THE SHOWER ACTIVITY OVER FLORIDA HAS MOVED EAST OF THE BASIN EXCEPT FOR SOME STRONG SHOWERS NEAR CAPE CANAVERAL. STRONG SHOWERS/ISOLATED THUNDERSTORMS ARE ALSO SOUTH OF THE AXIS IN THE STRAITS OF FLORIDA. ISOLATED SHOWERS AND POSSIBLE THUNDERSTORMS EXTEND UP TO 250 NM NORTH AND WEST OF THE AXIS ELSEWHERE. NORTHEAST TO EAST WINDS OF 15-20 KT ARE NORTH OF THE FRONTAL BOUNDARY BECOMING SOUTHEASTERLY ACROSS THE WESTERN GULF AS THEY WRAP AROUND THE SOUTHERN EDGE OF A SURFACE RIDGE COVERING MUCH OF THE EASTERN CONUS. DRY AIR ALOFT AROUND THE WEST SIDE OF THE UPPER TROUGH IS KEEPING THE FAR NW GULF UNDER FAIR CONDITIONS. THE WESTERN PORTION OF THE FRONT IS EXPECTED TO SPLIT FROM THE MAIN FRONT OVER THE NEXT 24 HOURS AND WILL DRIFT WEST AS A SURFACE TROUGH. SURFACE RIDGING WILL DOMINATE THE REMAINDER OF THE BASIN FOR THE NEXT SEVERAL DAYS. SHOWERS AND THUNDERSTORMS WILL LIKELY REMAIN ACROSS THE EASTERN GULF AND FLORIDA THROUGH AT LEAST MONDAY. CARIBBEAN SEA... UPPER LEVEL RIDGING COVERS THE WESTERN CARIBBEAN EXTENDING FROM SOUTH OF MEXICO ACROSS GUATEMALA TO EASTERN CUBA CONTINUING INTO THE WEST ATLC. DRY AIR ALOFT ACROSS THIS AREA IS HELPING PROVIDE FAIR CONDITIONS AT THE SURFACE. ONLY A FEW SHOWERS CONTINUE OVER HONDURAS AND SOUTH OF CUBA. HOWEVER...AN UPPER LEVEL TROUGH WITH AXIS NEAR 65W IS PROVIDING SOME UPPER LEVEL MOISTURE ACROSS THE FAR EASTERN CARIBBEAN ALONG WITH SOME DIFFLUENCE ALOFT SUPPORTING SCATTERED SHOWERS FROM 14N-17N EAST OF 71W. TRADEWIND FLOW OF 15-20 KT SPREADS ACROSS MUCH OF THE CENTRAL AND EASTERN CARIBBEAN. LITTLE CHANGE IS EXPECTED OVER THE NEXT 24 HOURS. MOISTURE AND LIKELY SHOWERS WILL REMAIN OVER THE NORTHEAST CARIBBEAN. ATLANTIC OCEAN... THE STATIONARY FRONT OVER THE SE GULF OF MEXICO EXTENDS INTO THE WEST ATLC ALONG 26N80W TO 32N74W...AS OF 0900 UTC. SCATTERED SHOWERS/ISOLATED THUNDERSTORMS EXTEND UP TO 120 NM EITHER SIDE OF THE AXIS. THE SYSTEM IS SUPPORTED BY A BROAD UPPER TROUGH COVERING MUCH OF THE EASTERN CONUS. AN UPPER LEVEL RIDGE IS TO THE EAST EXTENDING FROM EASTERN CUBA TO NEAR 31N68W. A LARGER SCALE UPPER RIDGE IS CENTERED NEAR 30N58W SUPPORTING A SURFACE RIDGE ANCHORED NEAR 43N42W. A WEAK UPPER LOW IS TO THE SOUTH OF THE UPPER RIDGE NEAR 21N65W WITH AXIS CONTINUING INTO THE CARIBBEAN. THE UPPER LOW/TROUGH IS SUPPORTING SCATTERED SHOWERS FROM 13N-17N WEST OF 56W INTO THE EASTERN CARIBBEAN. FARTHER EAST...AN UPPER LEVEL LOW NEAR 29N42W SUPPORTS A WEAK 1011 MB BROAD SURFACE LOW CENTERED NEAR 27N37W. A SURFACE TROUGH EXTENDS TOWARDS THE SW FROM THE LOW CENTER TO NEAR 20N42W. ISOLATED SHOWERS ARE TO THE NE FROM 28N-30N BETWEEN 31W-37W...AND TO THE WEST FROM 23N-30N BETWEEN 39W-42W. AN UPPER LEVEL RIDGE ALONG 16W COVERS THE REMAINDER OF THE EAST ATLC SUPPORTING A WEAK 1015 MB HIGH NEAR 20N31W. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ WALTON