000 AXNT20 KNHC 212321 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 805 PM EDT SUN JUL 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 2245 UTC. ...TROPICAL WAVES... TROPICAL WAVE WAS INTRODUCED ON THE 1800 UTC MAP JUST INLAND ALONG THE COAST OF AFRICA FROM 18N16W TO 10N14W. A SURGE OF DEEP MOISTURE IS EXPANDING ALONG THE COAST OF W AFRICA FROM SIERRA LEONE TO MAURITANIA AS DEPICTED IN TOTAL PRECIPITABLE WATER IMAGERY. CLUSTERS OF SCATTERED MODERATE/STRONG CONVECTION ARE FROM 8N-12N BETWEEN 15W-18W. TROPICAL WAVE EXTENDS FROM 22N53W TO 13N58W MOVING W-NW NEAR 15 KT. WAVE IS EMBEDDED WITHIN A HIGH AMPLITUDE SURGE OF DEEP MOISTURE AS DEPICTED IN TOTAL PRECIPITABLE WATER IMAGERY. WAVE IS WELL DEFINED ON SATELLITE IMAGERY.SCATTERED SHOWERS/ISOLATED THUNDERSTORMS ARE FROM 19N-20N BETWEEN 53W-56W WITH SCATTERED SHOWERS AND POSSIBLE ISOLATED THUNDERSTORMS FROM 15N-20N BETWEEN THE WAVE AND 60W. ...ITCZ/MONSOON TROUGH... THE MONSOON TROUGH EXTENDS ACROSS AFRICA INTO THE E TROPICAL ATLC NEAR 13N17W AND CONTINUES TO 9N28W WHERE THE ITCZ BEGINS AND CONTINUES ALONG 7N36W 3N45W TO SOUTH AMERICA NEAR 3N51W. SCATTERED STRONG CONVECTION IS FROM 7N-9N BETWEEN 28W-30W. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS WITHIN 90/120 NM EITHER SIDE OF THE MONSOON TROUGH/ITCZ BETWEEN 26W-31W. SCATTERED MODERATE WITH EMBEDDED CLUSTERS OF ISOLATED STRONG CONVECTION IS WITHIN 120 NM EITHER SIDE OF THE MONSOON TROUGH BETWEEN 21W-26W. ...DISCUSSION... GULF OF MEXICO... AN UPPER TROUGH EXTENDS FROM OVER MISSISSIPPI INTO THE NW GULF TO 26N93W GENERATING SCATTERED SHOWERS/ISOLATED THUNDERSTORMS N OF 27N TO OVER THE N GULF COAST BETWEEN 87W-96W. AN UPPER RIDGE COVERS THE E GULF ANCHORED NEAR 28N84W AND IS PROVIDING DIFFLUENCE ALOFT TO GENERATE SCATTERED SHOWERS/ISOLATED THUNDERSTORMS INLAND OVER THE FLORIDA PENINSULA. AN UPPER RIDGE INLAND OVER MEXICO IS PROVIDING DIFFLUENCE ALOFT TO GENERATE SCATTERED SHOWERS AND POSSIBLE ISOLATED THUNDERSTORMS WITHIN 120 NM ALONG THE COAST BETWEEN 20N-24N. OTHERWISE A SURFACE RIDGE EXTENDS FROM THE W ATLC ACROSS CENTRAL FLORIDA TO THE TEXAS COAST NEAR CORPUS CHRISTI. SURFACE RIDGE WILL REMAIN ALONG 28N THROUGH MON THEN FROM SW FLORIDA TO NE TEXAS TUE THROUGH FRI. CARIBBEAN SEA... AN UPPER RIDGE OVER THE E GULF OF MEXICO COVERS THE NW CARIBBEAN N OF 17N W OF 79W WHILE A SECOND UPPER RIDGE ANCHORED IN THE TROPICAL ATLC COVERS THE CARIBBEAN E OF 77W. THE UPPER TROUGH OVER THE W ATLC DIPS S OVER PORTIONS OF HAITI AND E CUBA TO JAMAICA LEAVING AN INVERTED UPPER TROUGH COVERING THE REMAINDER OF THE SW CARIBBEAN. THE MONSOON TROUGH EXTENDS FROM COLOMBIA NEAR 10N75W ACROSS PANAMA/COSTA RICA NEAR 9N82W GENERATING SCATTERED SHOWERS/ISOLATED THUNDERSTORMS S OF 13N W OF 77W. THE EASTERLY TRADE WINDS ARE GENERATING ISOLATED SHOWERS AND POSSIBLE ISOLATED THUNDERSTORMS OVER THE E CARIBBEAN FROM 12N- 17N E OF 70W ACROSS THE LESSER ANTILLES LEAVING THE REMAINDER OF THE CARIBBEAN WITH MOSTLY CLEAR SKIES THIS EVENING. THE TROPICAL WAVE WILL ENTER THE E CARIBBEAN LATE TONIGHT PASSING THROUGH THE CENTRAL CARIBBEAN MON NIGHT AND TUE THEN WILL WEAKEN OVER THE W CARIBBEAN WED AND THU. OTHERWISE FRESH TO STRONG EASTERLY TRADE WINDS OVER THE S CENTRAL CARIBBEAN WILL PERSIST THROUGH TUE THEN FRESH TRADES EXPECTED WED THROUGH FRI. HISPANIOLA... ISOLATED SHOWERS DOT HISPANIOLA THIS EVENING AND WILL CONTINUE INTO TONIGHT. THE UPPER TROUGH OVER W HAITI WILL REMAIN THROUGH MID WEEK. THE TROPICAL WAVE WILL MOVE ACROSS THE CARIBBEAN S OF HISPANIOLA LATE MON AND TUE INCREASING THE CHANCES OF HEAVY PRECIPITATION. ATLANTIC OCEAN... AN UPPER TROUGH COVERS THE W ATLC WITH THE AXIS EXTENDING THROUGH 32N68W ALONG 26N70W TO ACROSS E CUBA INTO THE N/CENTRAL CARIBBEAN GENERATING SCATTERED SHOWERS/ISOLATED THUNDERSTORMS N OF 27N BETWEEN 69W-73W AND WITHIN 60 NM ALONG THE COAST OF FLORIDA AND GEORGIA. SCATTERED SHOWERS AND POSSIBLE ISOLATED THUNDERSTORMS ARE OVER THE N BAHAMA ISLANDS FROM 25N-28N BETWEEN 75W-79W. AN UPPER LOW IS IN THE CENTRAL ATLC CENTERED NEAR 28N49W GENERATING SCATTERED SHOWERS/ISOLATED THUNDERSTORMS FROM 24N27N BETWEEN 47W-51W. OTHERWISE...A SURFACE RIDGE DOMINATES THE ATLC AND EXTENDS W OVER THE GULF OF MEXICO ANCHORED BY A 1023 HIGH IN THE W ATLC NEAR 29N64W...A 1023 MB HIGH IN THE CENTRAL ATLC NEAR 32N47W...AND A WEAK 1021 MB HIGH IN THE E ATLC NEAR 32N25W. AN UPPER TROUGH OVER THE NE ATLC IS SUPPORTING A WEAK 1019 MB LOW NEAR 33N32W WITH A SURFACE TROUGH EXTENDING SE ALONG 31N33W TO 29N38W. ISOLATED SHOWERS ARE POSSIBLE WITHIN 60 NM OF THE SURFACE TROUGH. THE NOAA GOES-R SATELLITE IMAGERY SHOWS SAHARAN AIR LAYER COVERING THE TROPICAL ATLC WITHIN 350/400 NM OF LINE FROM 13N54W ALONG 21N30W TO BEYOND 32N15W. SURFACE RIDGE WILL MEANDER FROM BERMUDA TO SE FLORIDA THROUGH FRI. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ PAW