000 AXNT20 KNHC 292354 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 805 PM EDT WED JUN 29 2011 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 2315 UTC. ...SPECIAL FEATURE... T.S. ARLENE IS CENTERED NEAR 21.4N 95.8W AT 30/0000 UTC OR ABOUT 90 NM ENE OF TUXPAN MEXICO AND ABOUT 125 NM E OF TAMPICO MEXICO MOVING W AT 4 KT. ESTIMATED MINIMUM CENTRAL PRESSURE IS 996 MB. MAXIMUM SUSTAINED WIND SPEED IS 45 KT WITH GUSTS TO 55 KT. PLEASE SEE THE LATEST NHC INTERMEDIATE PUBLIC ADVISORY UNDER AWIPS/WMO HEADERS MIATCPAT1/WTNT31 KNHC AND THE FULL FORECAST/ ADVISORY UNDER AWIPS/WMO HEADERS MIATCMAT1/WTNT21 KNHC FOR MORE DETAILS. SCATTERED/NUMEROUS STRONG CONVECTION IS WITHIN 75 NM IN THE S SEMICIRCLE WITH SCATTERED MODERATE/ ISOLATED STRONG CONVECTION COVERING THE REMAINDER OF THE AREA FROM S OF 24N W OF 93W TO INLAND OVER MEXICO. ...TROPICAL WAVES... TROPICAL WAVE IN THE W TROPICAL ATLC IS ALONG 51W/52W S OF 15N MOVING W NEAR 20 KT. WAVE REMAINS EMBEDDED WITHIN A MOISTURE SURGE AS INDICATED BY THE TOTAL PRECIPITABLE WATER IMAGERY. WAVE IS WELL DEFINE ON VISIBLE SATELLITE IMAGERY WITH THE UPPER LEVEL SATELLITE WINDS INDICATING A BROAD CURVATURE. WAVE IS BENEATH AN UPPER RIDGE WHICH IS ENHANCING CONVECTION IN THE VICINITY OF THE WAVE. TROPICAL WAVE IN THE CENTRAL CARIBBEAN IS ALONG 73W/74W BETWEEN 13N-19N MOVING W NEAR 10 KT. WAVE REMAINS EMBEDDED WITHIN A BROAD AREA OF DEEP MOISTURE THAT COVERS MOST OF THE CARIBBEAN. WAVE SIGNATURE IS MASKED BY AN UPPER LOW THAT CENTERED NEAR 16N73W. ISOLATED SHOWERS ARE WITHIN 120 NM EITHER SIDE OF THE WAVE AXIS MOSTLY DUE TO THE UPPER LOW THAN THE WAVE ITSELF. ...ITCZ/MONSOON TROUGH... THE MONSOON TROUGH EXTENDS ACROSS AFRICA INTO THE E ATLC NEAR 20N16W THEN S ALONG 13N19W TO 8N24W WITH THE ITCZ AXIS CONTINUING ALONG 10N35W 6N49W TO 7N59W. CLUSTERS OF SCATTERED MODERATE/ISOLATED STRONG CONVECTION ARE FROM 5N-10N BETWEEN 33W-45W. ...DISCUSSION... GULF OF MEXICO... THE PRIMARY FOCUS THIS EVENING IS TROPICAL STORM ARLENE APPROACHING THE E COAST OF MEXICO. SEE SPECIAL FEATURES ABOVE. A BROAD UPPER RIDGE ASSOCIATED WITH T.S. ARLENE COVERS THE GULF W OF 87W WITH AN UPPER TROUGH DIPPING S OVER THE NE GULF N OF 29N E OF 87W. DENSE CLOUD COVER WITH SCATTERED SHOWERS AND POSSIBLE ISOLATED THUNDERSTORMS WITH FRESH TO STRONG WINDS COVER THE AREA S OF 28N W OF 87W. THE UPPER RIDGE THAT LAST NIGHT EXTENDED OVER THE E GULF HAS SHIFTED E INTO THE W ATLC LEAVING N FLOW ALOFT OVER THE REMAINDER OF THE GULF. A SURFACE RIDGE EXTENDS FROM THE W ATLC ACROSS CENTRAL FLORIDA TO OVER SE TEXAS SPLIT BY A WEAK SURFACE TROUGH THAT EXTENDS FROM NEAR TALLAHASSEE FLORIDA TO 28N89W. THE N TO NW FLOW ALOFT CONVERGING WITH THE E TO SE WINDS AT THE SURFACE ARE PRODUCING SCATTERED SHOWERS/THUNDERSTORMS OVER THE SE GULF S OF 27N E OF 87W TO OVER S FLORIDA AND THROUGH THE STRAITS OF FLORIDA LEAVING ONLY THE FAR NW GULF UNDER CLEAR SKIES THIS EVENING. T.S. ARLENE IS EXPECTED TO MAKE LANDFALL ON THU WITH THE SURFACE RIDGE REMAINING OVER THE N GULF THROUGH MON. CARIBBEAN SEA... AN UPPER TROUGH DOMINATES THE CENTRAL CARIBBEAN EXTENDING FROM AN UPPER LOW S OF HAITI NEAR 16N73W SW TO PANAMA NEAR 9N80W WITH N FLOW ALOFT OVER THE W CARIBBEAN AND INDUCING AN UPPER RIDGE OVER THE E CARIBBEAN. SCATTERED SHOWERS/THUNDERSTORMS ARE AT THE BASE OF THE UPPER TROUGH AND ENHANCED BY THE CLOSE PROXIMITY OF THE MONSOON TROUGH...MOSTLY INLAND AND WITHIN 60 NM ALONG THE COASTAL WATERS OF PANAMA AND COSTA RICA. DIFFLUENT FLOW ALOFT OVER THE SE CARIBBEAN IS ENHANCING SCATTERED SHOWERS/ISOLATED THUNDERSTORMS S OF 15N E OF 68W ACROSS THE LESSER ANTILLES INTO THE W TROPICAL ATLC. FRESH TO STRONG EASTERLY TRADE WINDS CONTINUE ACROSS THE BASIN GENERATING ISOLATED SHOWERS/ THUNDERSTORMS MAINLY N OF 14N W OF 76W. THE CENTRAL CARIBBEAN TROPICAL WAVE WILL MOVE INTO THE W CARIBBEAN TONIGHT AND ACROSS THE NW CARIBBEAN THROUGH SAT. THE TROPICAL WAVE IN THE W TROPICAL ATLC WILL MOVE INTO E CARIBBEAN EARLY FRI ACROSS THE CENTRAL CARIBBEAN SAT AND INTO THE W CARIBBEAN SUN AND MON. THE E TRADE WINDS WILL PERSIST OVER MOST OF THE CARIBBEAN BASIN THROUGH FRI THEN DIMINISH SAT AND SUN AS ATLC SURFACE RIDGE WEAKENS. ATLANTIC OCEAN... WEAK UPPER RIDGE REMAINS OVER THE W ATLC EXTENDING FROM S FLORIDA TO BEYOND 32N73W PROVIDING DIFFLUENT FLOW TO GENERATE SCATTERED SHOWERS/THUNDERSTORMS S OF 28N TO OVER CUBA W OF 76W TO ACROSS THE FLORIDA PENINSULA. ISOLATED SHOWERS/THUNDERSTORMS COVER THE REMAINDER OF THE AREA N OF 28N W OF 74W. THE UPPER RIDGE OVER THE E CARIBBEAN IS PROVIDING DIFFLUENT FLOW ALOFT OVER THE W TROPICAL ATLC/SE CARIBBEAN ENHANCING SCATTERED SHOWERS/ISOLATED THUNDERSTORMS FROM 10N-15N W OF 51W ACROSS THE LESSER ANTILLES INTO THE SE CARIBBEAN. A SURFACE RIDGE DOMINATES THE ATLC BASIN EXTENDING FROM THE E ATLC THROUGH 33N37W AND A 1024 MB HIGH NEAR 33N46W ALONG 30N58W ACROSS CENTRAL FLORIDA INTO THE GULF OF MEXICO LEAVING THE REMAINDER OF THE BASIN UNDER RELATIVELY CLEAR SKIES THIS EVENING. A SURFACE RIDGE WILL REMAIN NEAR 29N THROUGH MON WEAKENING SOMEWHAT OVER THE WEEKEND. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ PAW 000 AXNT20 KNHC 292354 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 805 PM EDT WED JUN 29 2011 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 2315 UTC. ...SPECIAL FEATURE... T.S. ARLENE IS CENTERED NEAR 21.4N 95.8W AT 30/0000 UTC OR ABOUT 90 NM ENE OF TUXPAN MEXICO AND ABOUT 125 NM E OF TAMPICO MEXICO MOVING W AT 4 KT. ESTIMATED MINIMUM CENTRAL PRESSURE IS 996 MB. MAXIMUM SUSTAINED WIND SPEED IS 45 KT WITH GUSTS TO 55 KT. PLEASE SEE THE LATEST NHC INTERMEDIATE PUBLIC ADVISORY UNDER AWIPS/WMO HEADERS MIATCPAT1/WTNT31 KNHC AND THE FULL FORECAST/ ADVISORY UNDER AWIPS/WMO HEADERS MIATCMAT1/WTNT21 KNHC FOR MORE DETAILS. SCATTERED/NUMEROUS STRONG CONVECTION IS WITHIN 75 NM IN THE S SEMICIRCLE WITH SCATTERED MODERATE/ ISOLATED STRONG CONVECTION COVERING THE REMAINDER OF THE AREA FROM S OF 24N W OF 93W TO INLAND OVER MEXICO. ...TROPICAL WAVES... TROPICAL WAVE IN THE W TROPICAL ATLC IS ALONG 51W/52W S OF 15N MOVING W NEAR 20 KT. WAVE REMAINS EMBEDDED WITHIN A MOISTURE SURGE AS INDICATED BY THE TOTAL PRECIPITABLE WATER IMAGERY. WAVE IS WELL DEFINE ON VISIBLE SATELLITE IMAGERY WITH THE UPPER LEVEL SATELLITE WINDS INDICATING A BROAD CURVATURE. WAVE IS BENEATH AN UPPER RIDGE WHICH IS ENHANCING CONVECTION IN THE VICINITY OF THE WAVE. TROPICAL WAVE IN THE CENTRAL CARIBBEAN IS ALONG 73W/74W BETWEEN 13N-19N MOVING W NEAR 10 KT. WAVE REMAINS EMBEDDED WITHIN A BROAD AREA OF DEEP MOISTURE THAT COVERS MOST OF THE CARIBBEAN. WAVE SIGNATURE IS MASKED BY AN UPPER LOW THAT CENTERED NEAR 16N73W. ISOLATED SHOWERS ARE WITHIN 120 NM EITHER SIDE OF THE WAVE AXIS MOSTLY DUE TO THE UPPER LOW THAN THE WAVE ITSELF. ...ITCZ/MONSOON TROUGH... THE MONSOON TROUGH EXTENDS ACROSS AFRICA INTO THE E ATLC NEAR 20N16W THEN S ALONG 13N19W TO 8N24W WITH THE ITCZ AXIS CONTINUING ALONG 10N35W 6N49W TO 7N59W. CLUSTERS OF SCATTERED MODERATE/ISOLATED STRONG CONVECTION ARE FROM 5N-10N BETWEEN 33W-45W. ...DISCUSSION... GULF OF MEXICO... THE PRIMARY FOCUS THIS EVENING IS TROPICAL STORM ARLENE APPROACHING THE E COAST OF MEXICO. SEE SPECIAL FEATURES ABOVE. A BROAD UPPER RIDGE ASSOCIATED WITH T.S. ARLENE COVERS THE GULF W OF 87W WITH AN UPPER TROUGH DIPPING S OVER THE NE GULF N OF 29N E OF 87W. DENSE CLOUD COVER WITH SCATTERED SHOWERS AND POSSIBLE ISOLATED THUNDERSTORMS WITH FRESH TO STRONG WINDS COVER THE AREA S OF 28N W OF 87W. THE UPPER RIDGE THAT LAST NIGHT EXTENDED OVER THE E GULF HAS SHIFTED E INTO THE W ATLC LEAVING N FLOW ALOFT OVER THE REMAINDER OF THE GULF. A SURFACE RIDGE EXTENDS FROM THE W ATLC ACROSS CENTRAL FLORIDA TO OVER SE TEXAS SPLIT BY A WEAK SURFACE TROUGH THAT EXTENDS FROM NEAR TALLAHASSEE FLORIDA TO 28N89W. THE N TO NW FLOW ALOFT CONVERGING WITH THE E TO SE WINDS AT THE SURFACE ARE PRODUCING SCATTERED SHOWERS/THUNDERSTORMS OVER THE SE GULF S OF 27N E OF 87W TO OVER S FLORIDA AND THROUGH THE STRAITS OF FLORIDA LEAVING ONLY THE FAR NW GULF UNDER CLEAR SKIES THIS EVENING. T.S. ARLENE IS EXPECTED TO MAKE LANDFALL ON THU WITH THE SURFACE RIDGE REMAINING OVER THE N GULF THROUGH MON. CARIBBEAN SEA... AN UPPER TROUGH DOMINATES THE CENTRAL CARIBBEAN EXTENDING FROM AN UPPER LOW S OF HAITI NEAR 16N73W SW TO PANAMA NEAR 9N80W WITH N FLOW ALOFT OVER THE W CARIBBEAN AND INDUCING AN UPPER RIDGE OVER THE E CARIBBEAN. SCATTERED SHOWERS/THUNDERSTORMS ARE AT THE BASE OF THE UPPER TROUGH AND ENHANCED BY THE CLOSE PROXIMITY OF THE MONSOON TROUGH...MOSTLY INLAND AND WITHIN 60 NM ALONG THE COASTAL WATERS OF PANAMA AND COSTA RICA. DIFFLUENT FLOW ALOFT OVER THE SE CARIBBEAN IS ENHANCING SCATTERED SHOWERS/ISOLATED THUNDERSTORMS S OF 15N E OF 68W ACROSS THE LESSER ANTILLES INTO THE W TROPICAL ATLC. FRESH TO STRONG EASTERLY TRADE WINDS CONTINUE ACROSS THE BASIN GENERATING ISOLATED SHOWERS/ THUNDERSTORMS MAINLY N OF 14N W OF 76W. THE CENTRAL CARIBBEAN TROPICAL WAVE WILL MOVE INTO THE W CARIBBEAN TONIGHT AND ACROSS THE NW CARIBBEAN THROUGH SAT. THE TROPICAL WAVE IN THE W TROPICAL ATLC WILL MOVE INTO E CARIBBEAN EARLY FRI ACROSS THE CENTRAL CARIBBEAN SAT AND INTO THE W CARIBBEAN SUN AND MON. THE E TRADE WINDS WILL PERSIST OVER MOST OF THE CARIBBEAN BASIN THROUGH FRI THEN DIMINISH SAT AND SUN AS ATLC SURFACE RIDGE WEAKENS. ATLANTIC OCEAN... WEAK UPPER RIDGE REMAINS OVER THE W ATLC EXTENDING FROM S FLORIDA TO BEYOND 32N73W PROVIDING DIFFLUENT FLOW TO GENERATE SCATTERED SHOWERS/THUNDERSTORMS S OF 28N TO OVER CUBA W OF 76W TO ACROSS THE FLORIDA PENINSULA. ISOLATED SHOWERS/THUNDERSTORMS COVER THE REMAINDER OF THE AREA N OF 28N W OF 74W. THE UPPER RIDGE OVER THE E CARIBBEAN IS PROVIDING DIFFLUENT FLOW ALOFT OVER THE W TROPICAL ATLC/SE CARIBBEAN ENHANCING SCATTERED SHOWERS/ISOLATED THUNDERSTORMS FROM 10N-15N W OF 51W ACROSS THE LESSER ANTILLES INTO THE SE CARIBBEAN. A SURFACE RIDGE DOMINATES THE ATLC BASIN EXTENDING FROM THE E ATLC THROUGH 33N37W AND A 1024 MB HIGH NEAR 33N46W ALONG 30N58W ACROSS CENTRAL FLORIDA INTO THE GULF OF MEXICO LEAVING THE REMAINDER OF THE BASIN UNDER RELATIVELY CLEAR SKIES THIS EVENING. A SURFACE RIDGE WILL REMAIN NEAR 29N THROUGH MON WEAKENING SOMEWHAT OVER THE WEEKEND. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ PAW