000 AXNT20 KNHC 291805 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 205 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 1715 UTC. ...SPECIAL FEATURE... T.S. ARLENE IS CENTERED NEAR 21.1N 95.9W...OR ABOUT 85 NM E OF TUXPAN...AS OF 1800 UTC. THE STORM IS MOVING W AT 7 KT. MINIMUM CENTRAL PRESSURE IS 1000 MB WHILE MAXIMUM SUSTAINED WINDS ARE 45 KT WITH GUSTS TO 55 KT. ARLENE IS EXPECTED MOVE SLOWLY WESTWARD TOWARDS THE MEXICAN COAST. STRENGTHENING IS FORECAST...AND ARLENE COULD APPROACH HURRICANE STRENGTH PRIOR TO LANDFALL. SEE 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. 20 KT WINDS EXTEND UP TO 300 NM N AND E OF THE CENTER. SATELLITE IMAGERY AND RADAR FROM ALVARADO MEXICO INDICATES NUMEROUS STRONG CONVECTION IS WRAPPING AROUND ALL QUADRANTS EXCEPT TO THE NORTH FROM 18N-23N BETWEEN 92W-98W REACHING EASTERN MEXICO. NUMEROUS MODERATE/SCATTERED STRONG CONVECTION IS PRESENT FROM 18N-24N BETWEEN 90W-95W. SOME SHOWERS ASSOCIATED WITH THE OUTER RAINBANDS ARE ARLENE ARE REACHING NE MEXICO AND EXTREME S TEXAS AS SEEN IN THE BROWNSVILLE RADAR. ...TROPICAL WAVES... A TROPICAL WAVE IS ACROSS THE CENTRAL ATLC ALONG 13N50W TO 7N51W MOVING W NEAR 15-20 KT. SATELLITE IMAGERY SHOWS A VORTICITY MAXIMUM NEAR 11N51W...THOUGH IT DOES NOT APPEAR TO BE A CLOSED LOW AT THE SURFACE YET FROM A 1240 UTC ASCAT PASS. THE WAVE IS EVIDENT FROM THE TOTAL PRECIPITABLE WATER IMAGERY AS A DISTINCT BULGE IN THE MOISTURE ON THE EAST SIDE OF THE TROUGH AXIS. CONVECTION HAS BEEN MINIMAL THIS SYSTEM OVER THE LAST DAY OR SO. A TROPICAL WAVE IS S OF HAITI ALONG 73W FROM 13N-19N MOVING W NEAR 10 KT. THIS WAVE HAS BECOME INDISTINCT DURING THE PAST 24 HOURS...POSSIBLY DUE TO THE INTERACTION WITH AN UPPER LEVEL LOW NOW S OF HAITI NEAR 15N73W. SOME ENHANCED MOISTURE VALUES AS SEEN IN THE TOTAL PRECIPITABLE WATER IMAGERY STILL REMAIN IN THE VICINITY OF THE WAVE. SCATTERED MODERATE CONVECTION IS NEAR THE WAVE AXIS FROM 16N-18N BETWEEN 71W-75WW. ...ITCZ/MONSOON TROUGH... THE MONSOON TROUGH EXTENDS ACROSS AFRICA FROM THE PRIME MERIDIAN AT 24N ALONG 18N12W 11N15W THEN OVER THE EASTERN ATLANTIC TO 8N20W. THE ITCZ CONTINUES FROM 8N20W TO 7N33W TO 7N49W. A SEPARATE MONSOON TROUGH IN THE SW CARIBBEAN SEA EXTENDS FROM 10N75W OVER COLOMBIA WESTWARD TO 10N83W OVER PANAMA. SCATTERED MODERATE/STRONG CONVECTION IS OCCURRING WITHIN 180 NM N OF THE AXIS 20W-27W...FROM 32W-43W...AND AGAIN FROM 79W-83W. ...DISCUSSION... GULF OF MEXICO... TROPICAL STORM ARLENE IS CURRENTLY AFFECTING MUCH OF THE SW GULF OF MEXICO. SEE SPECIAL FEATURES SECTION ABOVE FOR MORE DETAILS. ELSEWHERE AT THE SURFACE...WINDS ARE LIGHT THROUGHOUT THE GULF WITH NO SIGNIFICANT DEEP CONVECTION. A SURFACE TROUGH EXTENDS FROM OVER THE FLORIDA PANHANDLE FROM 30N83W TO 29N88W. SCATTERED SHOWERS ARE OCCURRING WITHIN 60 NM OF THE TROUGH AXIS. IN THE UPPER LEVELS... ANTICYCLONIC FLOW ASSOCIATED WITH THE OUTFLOW OF T.S. ARLENE COVERS THE LOWER TWO-THIRDS OF THE GULF AND NUMEROUS HIGH CLOUDS ARE EMBEDDED IN THIS FLOW. AN EAST-WEST ORIENTED TROUGH RESIDES ALONG THE NORTHERN GULF OF MEXICO. WITH THE EXCEPTION OF THE NW GULF...SUBSTANTIAL MOISTURE IS PRESENT OVER ALL OF THE GULF AND FLORIDA. EXPECT CONTINUED MOISTURE AND SHOWER ACTIVITY TO REMAIN ACROSS THE WESTERN GULF IN ASSOCIATION WITH ARLENE AS WELL AS IN AND AROUND FLORIDA DURING THE NEXT 24 HOURS. CARIBBEAN SEA... BUOY...ISLAND...AND ASCAT OBSERVATIONS INDICATE THAT THE CENTRAL CARIBBEAN HAS SURFACE WINDS OF 20-25 KT WHILE THE EASTERN AND WESTERN CARIBBEAN HAVE LIGHT WINDS. ASIDE FROM THE AFOREMENTIONED TROPICAL WAVES PRODUCING SOME DEEP CONVECTION...THE REMAINDER OF THE CARIBBEAN SEA IS EXHIBITING NO SIGNIFICANT CONVECTION. IN THE UPPER LEVELS...A NORTH-SOUTH STRETCHED UPPER LOW IS LOCATED SOUTH OF HISPANIOLA WITH RIDGING EXTENDING OVER BOTH THE EASTERN AND WESTERN CARIBBEAN. SOME INCREASED CHANCE OF DEEP CONVECTION IS LIKELY OVER THE NEXT DAY IN THE WESTERN CARIBBEAN AS THE TROPICAL WAVE MOVES WESTWARD. ATLANTIC OCEAN... AN ELONGATED WEST-SOUTHWEST TO EAST-NORTHEAST SURFACE RIDGE EXTENDS ALONG 30N ACROSS THE ATLANTIC. SURFACE WINDS ARE GENERALLY LIGHT EXCEPT FOR JUST EAST OF THE LESSER ANTILLES WHERE E-NE TRADEWINDS OF 20-25 KT ARE OCCURRING. A SURFACE TROUGH NEAR THE SE BAHAMAS EXTENDS FROM 25N70W TO 21N73W WITH LITTLE SHOWER ACTIVITY. SCATTERED MODERATE CONVECTION IS OCCURRING EAST OF FLORIDA N OF 23N AND W OF 77W. SCATTERED MODERATE CONVECTION ALSO RESIDES FROM 9N-13N BETWEEN THE LESSER ANTILLES AND 55W. IN THE UPPER LEVELS...RIDGING GENERALLY EXTENDS ACROSS THE ATLANTIC ALONG 12N WITH A PROMINENT SUBSIDENT LOW CENTERED NEAR 27N50W. DURING THE NEXT DAY...SHOWERS AND DEEP CONVECTION SHOULD CONTINUE JUST EAST OF FLORIDA AND DEEP CONVECTION MAY BECOME MORE PREVALENT OVER THE LESSER ANTILLES AS THE TROPICAL WAVE APPROACHES. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ LANDSEA 000 AXNT20 KNHC 291805 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 205 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 1715 UTC. ...SPECIAL FEATURE... T.S. ARLENE IS CENTERED NEAR 21.1N 95.9W...OR ABOUT 85 NM E OF TUXPAN...AS OF 1800 UTC. THE STORM IS MOVING W AT 7 KT. MINIMUM CENTRAL PRESSURE IS 1000 MB WHILE MAXIMUM SUSTAINED WINDS ARE 45 KT WITH GUSTS TO 55 KT. ARLENE IS EXPECTED MOVE SLOWLY WESTWARD TOWARDS THE MEXICAN COAST. STRENGTHENING IS FORECAST...AND ARLENE COULD APPROACH HURRICANE STRENGTH PRIOR TO LANDFALL. SEE 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. 20 KT WINDS EXTEND UP TO 300 NM N AND E OF THE CENTER. SATELLITE IMAGERY AND RADAR FROM ALVARADO MEXICO INDICATES NUMEROUS STRONG CONVECTION IS WRAPPING AROUND ALL QUADRANTS EXCEPT TO THE NORTH FROM 18N-23N BETWEEN 92W-98W REACHING EASTERN MEXICO. NUMEROUS MODERATE/SCATTERED STRONG CONVECTION IS PRESENT FROM 18N-24N BETWEEN 90W-95W. SOME SHOWERS ASSOCIATED WITH THE OUTER RAINBANDS ARE ARLENE ARE REACHING NE MEXICO AND EXTREME S TEXAS AS SEEN IN THE BROWNSVILLE RADAR. ...TROPICAL WAVES... A TROPICAL WAVE IS ACROSS THE CENTRAL ATLC ALONG 13N50W TO 7N51W MOVING W NEAR 15-20 KT. SATELLITE IMAGERY SHOWS A VORTICITY MAXIMUM NEAR 11N51W...THOUGH IT DOES NOT APPEAR TO BE A CLOSED LOW AT THE SURFACE YET FROM A 1240 UTC ASCAT PASS. THE WAVE IS EVIDENT FROM THE TOTAL PRECIPITABLE WATER IMAGERY AS A DISTINCT BULGE IN THE MOISTURE ON THE EAST SIDE OF THE TROUGH AXIS. CONVECTION HAS BEEN MINIMAL THIS SYSTEM OVER THE LAST DAY OR SO. A TROPICAL WAVE IS S OF HAITI ALONG 73W FROM 13N-19N MOVING W NEAR 10 KT. THIS WAVE HAS BECOME INDISTINCT DURING THE PAST 24 HOURS...POSSIBLY DUE TO THE INTERACTION WITH AN UPPER LEVEL LOW NOW S OF HAITI NEAR 15N73W. SOME ENHANCED MOISTURE VALUES AS SEEN IN THE TOTAL PRECIPITABLE WATER IMAGERY STILL REMAIN IN THE VICINITY OF THE WAVE. SCATTERED MODERATE CONVECTION IS NEAR THE WAVE AXIS FROM 16N-18N BETWEEN 71W-75WW. ...ITCZ/MONSOON TROUGH... THE MONSOON TROUGH EXTENDS ACROSS AFRICA FROM THE PRIME MERIDIAN AT 24N ALONG 18N12W 11N15W THEN OVER THE EASTERN ATLANTIC TO 8N20W. THE ITCZ CONTINUES FROM 8N20W TO 7N33W TO 7N49W. A SEPARATE MONSOON TROUGH IN THE SW CARIBBEAN SEA EXTENDS FROM 10N75W OVER COLOMBIA WESTWARD TO 10N83W OVER PANAMA. SCATTERED MODERATE/STRONG CONVECTION IS OCCURRING WITHIN 180 NM N OF THE AXIS 20W-27W...FROM 32W-43W...AND AGAIN FROM 79W-83W. ...DISCUSSION... GULF OF MEXICO... TROPICAL STORM ARLENE IS CURRENTLY AFFECTING MUCH OF THE SW GULF OF MEXICO. SEE SPECIAL FEATURES SECTION ABOVE FOR MORE DETAILS. ELSEWHERE AT THE SURFACE...WINDS ARE LIGHT THROUGHOUT THE GULF WITH NO SIGNIFICANT DEEP CONVECTION. A SURFACE TROUGH EXTENDS FROM OVER THE FLORIDA PANHANDLE FROM 30N83W TO 29N88W. SCATTERED SHOWERS ARE OCCURRING WITHIN 60 NM OF THE TROUGH AXIS. IN THE UPPER LEVELS... ANTICYCLONIC FLOW ASSOCIATED WITH THE OUTFLOW OF T.S. ARLENE COVERS THE LOWER TWO-THIRDS OF THE GULF AND NUMEROUS HIGH CLOUDS ARE EMBEDDED IN THIS FLOW. AN EAST-WEST ORIENTED TROUGH RESIDES ALONG THE NORTHERN GULF OF MEXICO. WITH THE EXCEPTION OF THE NW GULF...SUBSTANTIAL MOISTURE IS PRESENT OVER ALL OF THE GULF AND FLORIDA. EXPECT CONTINUED MOISTURE AND SHOWER ACTIVITY TO REMAIN ACROSS THE WESTERN GULF IN ASSOCIATION WITH ARLENE AS WELL AS IN AND AROUND FLORIDA DURING THE NEXT 24 HOURS. CARIBBEAN SEA... BUOY...ISLAND...AND ASCAT OBSERVATIONS INDICATE THAT THE CENTRAL CARIBBEAN HAS SURFACE WINDS OF 20-25 KT WHILE THE EASTERN AND WESTERN CARIBBEAN HAVE LIGHT WINDS. ASIDE FROM THE AFOREMENTIONED TROPICAL WAVES PRODUCING SOME DEEP CONVECTION...THE REMAINDER OF THE CARIBBEAN SEA IS EXHIBITING NO SIGNIFICANT CONVECTION. IN THE UPPER LEVELS...A NORTH-SOUTH STRETCHED UPPER LOW IS LOCATED SOUTH OF HISPANIOLA WITH RIDGING EXTENDING OVER BOTH THE EASTERN AND WESTERN CARIBBEAN. SOME INCREASED CHANCE OF DEEP CONVECTION IS LIKELY OVER THE NEXT DAY IN THE WESTERN CARIBBEAN AS THE TROPICAL WAVE MOVES WESTWARD. ATLANTIC OCEAN... AN ELONGATED WEST-SOUTHWEST TO EAST-NORTHEAST SURFACE RIDGE EXTENDS ALONG 30N ACROSS THE ATLANTIC. SURFACE WINDS ARE GENERALLY LIGHT EXCEPT FOR JUST EAST OF THE LESSER ANTILLES WHERE E-NE TRADEWINDS OF 20-25 KT ARE OCCURRING. A SURFACE TROUGH NEAR THE SE BAHAMAS EXTENDS FROM 25N70W TO 21N73W WITH LITTLE SHOWER ACTIVITY. SCATTERED MODERATE CONVECTION IS OCCURRING EAST OF FLORIDA N OF 23N AND W OF 77W. SCATTERED MODERATE CONVECTION ALSO RESIDES FROM 9N-13N BETWEEN THE LESSER ANTILLES AND 55W. IN THE UPPER LEVELS...RIDGING GENERALLY EXTENDS ACROSS THE ATLANTIC ALONG 12N WITH A PROMINENT SUBSIDENT LOW CENTERED NEAR 27N50W. DURING THE NEXT DAY...SHOWERS AND DEEP CONVECTION SHOULD CONTINUE JUST EAST OF FLORIDA AND DEEP CONVECTION MAY BECOME MORE PREVALENT OVER THE LESSER ANTILLES AS THE TROPICAL WAVE APPROACHES. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ LANDSEA