000 AXNT20 KNHC 192358 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 805 PM EDT TUE JUL 19 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 FEATURES... TROPICAL STORM BRET IS CENTERED NEAR 30.4N 75.5W AT 19/2100 UTC OR 285 NM S OF CAPE HATTERAS NORTH CAROLINA MOVING NE AT 7 KT. ESTIMATED MINIMUM CENTRAL PRESSURE IS 999 MB. MAXIMUM SUSTAINED WIND SPEED IS 45 KT WITH GUSTS TO 55 KT. SCATTERED MODERATE CONVECTION IS LIMITED TO WITHIN 120 NM SW QUADRANT AND BRET IS FORECAST TO TRACK NE OVER THE NEXT 2 TO 3 DAYS. NORTH AND NORTHWESTERLY MIDDLE TO UPPER LEVEL SHEAR IS EXPECTED TO IMPART A GRADUAL WEAKENING TREND TO THE SYSTEM THROUGH EARLY FRIDAY. SEE LATEST NHC FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMAT2/WTNT22 KNHC FOR MORE DETAILS. ...TROPICAL WAVES... TROPICAL WAVE IS ANALYZED FROM 10N37W TO 18N36W MOVING W AT 20 KT. THE WAVE IS LOCATED ON THE LEADING EDGE OF A RATHER LARGE AND BROAD AREA OF LOW-LEVEL MOISTURE TO THE EAST OF THE WAVE AXIS AS NOTED ON TOTAL PRECIPITABLE WATER IMAGERY. THIS ALONG WITH OVERALL BROAD CYCLONIC FLOW S OF 15N BETWEEN 30W-40W ACCOMPANY THE WAVE WHICH CONTINUES TO PERTURB THE MONSOON TROUGH AXIS. ISOLATED MODERATE CONVECTION IS FROM 10N-15N BETWEEN 29W-35W. TROPICAL WAVE IS ANALYZED FROM 13N71W TO 22N67W MOVING W AT 20 KT. THE WAVE APPEARS VERY BROAD ON SATELLITE IMAGERY AND CONTINUES TO INTERACT ALOFT WITH AN UPPER LEVEL LOW CENTERED NEAR 18N70W. BOTH THE LOW-LEVEL CONVERGENCE AND UPPER LEVEL DIFFLUENCE ARE GENERATING AN AREA OF WIDELY SCATTERED MODERATE CONVECTION FROM 20N-23N BETWEEN 62W-68W. TOTAL PRECIPITABLE WATER IMAGERY ALSO SHOWS A HIGH CONTENT OF VERTICAL ATMOSPHERIC MOISTURE ALONG 60W AND THE ASSOCIATED SCATTERED SHOWERS AND ISOLATED TSTMS OCCURRING FROM 10N-20N BETWEEN 58W-61W. TROPICAL WAVE IS ANALYZED FROM 14N TO 21N ALONG 87W MOVING W AT 20 KT. THE WAVE EXHIBITS CYCLONIC TURNING OF THE LOW-LEVEL CLOUD FIELD WHICH HAS MOVED ONSHORE ACROSS THE YUCATAN THIS EVENING. PEAK DAYTIME HEATING AND INSTABILITY HAS GENERATED SCATTERED MODERATE CONVECTION OVER THE SW YUCATAN PENINSULA AND NORTHERN GUATEMALA FROM 16N-20N BETWEEN 89W-92W. ...ITCZ/MONSOON TROUGH... THE MONSOON TROUGH EXTENDS FROM THE AFRICAN COAST NEAR 10N13W TO 08N20W TO 13N31W 06N45W. THE INTERTROPICAL CONVERGENCE ZONE AXIS EXTENDS FROM 06N45W TO 09N61W. ISOLATED MODERATE CONVECTION IS FROM 06N-13N BETWEEN 15W-18W. SCATTERED MODERATE CONVECTION IS FROM 05N-08N BETWEEN 32W-40W...AND FROM 09N-12N BETWEEN 59W-62W. ...DISCUSSION... GULF OF MEXICO... WATER VAPOR IMAGERY INDICATES AN UPPER LEVEL LOW IS CENTERED OVER THE CENTRAL GULF NEAR 27N88W WHICH IS PROVIDING FOR AMPLE MIDDLE TO UPPER LEVEL LIFT ACROSS MUCH OF THE GULF BASIN THIS EVENING. WHILE A RELATIVELY WEAK SURFACE RIDGE EXTENDS ACROSS THE NE GULF ANCHORED BY A 1017 MB HIGH CENTERED OVER SOUTHERN ALABAMA...SOUTHERLY MOISTURE TRANSPORT AND INSTABILITY ACROSS PORTIONS OF THE WESTERN GULF ARE GENERATING ISOLATED SHOWERS AND TSTMS FROM 23N-29N BETWEEN 86W-97W. THE SURFACE HIGH IS EXPECTED TO SHIFT SOUTHEASTWARD OVER THE NEXT 24-36 HOURS AS AN AREA OF LOW PRESSURE DEVELOPS ACROSS THE WESTERN HIGH PLAINS OF THE U.S. CARIBBEAN SEA... AS MENTIONED ABOVE...A TROPICAL WAVE IS MOVING INTO THE CENTRAL CARIBBEAN AND CONTINUES TO INTERACT WITH AN UPPER LEVEL LOW CENTERED NEAR 18N70W. WHILE MOST OF THE ACTIVE CONVECTION IS LOCATED N OF 20N...SCATTERED SHOWERS AND ISOLATED TSTMS LOCATED WELL TO THE EAST OF THE WAVE AXIS ALONG 60W ARE EXPECTED TO IMPACT THE LESSER ANTILLES THIS EVENING INTO EARLY WEDNESDAY. FARTHER WEST...AN UPPER LEVEL ANTICYCLONE IS CENTERED OVER WESTERN CUBA NEAR 22N80W AND EXTENDS AN UPPER LEVEL RIDGE AXIS SOUTHWARD TO OVER PANAMA NEAR 10N80W. MOSTLY FAIR CONDITIONS ARE NOTED OVER MUCH OF THE WESTERN CARIBBEAN THIS EVENING...HOWEVER WITH AMPLE UPPER LEVEL DIFFLUENCE IN PLACE AND PEAK DAYTIME HEATING ACROSS CUBA...SCATTERED SHOWERS AND TSTMS ARE OCCURRING OVER MUCH OF INTERIOR CUBA BETWEEN 76W-84W. OTHERWISE...THE TROPICAL WAVE ALONG 87W IS FORECAST TO MOVE INLAND ACROSS BELIZE...THE YUCATAN PENINSULA...AND GUATEMALA DURING THE NEXT 12-24 HOURS. ATLANTIC OCEAN... TROPICAL STORM BRET CONTINUES TO RESIDE WITHIN A WEAKNESS OF THE SUBTROPICAL RIDGE ACROSS THE W ATLC THIS EVENING. AS BRET TRACKS NE OVER THE NEXT FEW DAYS THE SURFACE RIDGE AXIS IS EXPECTED TO RE-ESTABLISH ITSELF ALONG 26N THROUGH THE REMAINDER OF THE WEEK AND GRADUALLY SHIFT NORTHWARD TO 29N BY SATURDAY. FARTHER TO THE E-NE OF BRET THIS EVENING WATER VAPOR IMAGERY SHOWS A SHORTWAVE UPPER LEVEL TROUGH EAST OF BERMUDA ALONG 64W THAT SUPPORTS A 1013 MB LOW CENTERED NEAR 33N63W. THE LOW CONTINUES TO RAPIDLY PROGRESS EASTWARD WITH SCATTERED SHOWERS AND ISOLATED TSTMS OCCURRING OVER THE AREA FROM 30N-35N BETWEEN 53W-62W. THIS LOW IS FORECAST TO MOVE NE THEN MORE NORTH OVER THE NEXT 24 HOURS AS A STRONG 1034 MB AZORES HIGH IS CENTERED NEAR 39N29W. THIS HIGH CARRIES INFLUENCE ACROSS THE REMAINDER OF THE CENTRAL AND EASTERN TROPICAL ATLC N OF 18N WITH MOSTLY FAIR CONDITIONS AND A LARGE AREA OF NE TO E WINDS OF 15 TO 20 KT. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ HUFFMAN 000 AXNT20 KNHC 192358 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 805 PM EDT TUE JUL 19 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 FEATURES... TROPICAL STORM BRET IS CENTERED NEAR 30.4N 75.5W AT 19/2100 UTC OR 285 NM S OF CAPE HATTERAS NORTH CAROLINA MOVING NE AT 7 KT. ESTIMATED MINIMUM CENTRAL PRESSURE IS 999 MB. MAXIMUM SUSTAINED WIND SPEED IS 45 KT WITH GUSTS TO 55 KT. SCATTERED MODERATE CONVECTION IS LIMITED TO WITHIN 120 NM SW QUADRANT AND BRET IS FORECAST TO TRACK NE OVER THE NEXT 2 TO 3 DAYS. NORTH AND NORTHWESTERLY MIDDLE TO UPPER LEVEL SHEAR IS EXPECTED TO IMPART A GRADUAL WEAKENING TREND TO THE SYSTEM THROUGH EARLY FRIDAY. SEE LATEST NHC FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMAT2/WTNT22 KNHC FOR MORE DETAILS. ...TROPICAL WAVES... TROPICAL WAVE IS ANALYZED FROM 10N37W TO 18N36W MOVING W AT 20 KT. THE WAVE IS LOCATED ON THE LEADING EDGE OF A RATHER LARGE AND BROAD AREA OF LOW-LEVEL MOISTURE TO THE EAST OF THE WAVE AXIS AS NOTED ON TOTAL PRECIPITABLE WATER IMAGERY. THIS ALONG WITH OVERALL BROAD CYCLONIC FLOW S OF 15N BETWEEN 30W-40W ACCOMPANY THE WAVE WHICH CONTINUES TO PERTURB THE MONSOON TROUGH AXIS. ISOLATED MODERATE CONVECTION IS FROM 10N-15N BETWEEN 29W-35W. TROPICAL WAVE IS ANALYZED FROM 13N71W TO 22N67W MOVING W AT 20 KT. THE WAVE APPEARS VERY BROAD ON SATELLITE IMAGERY AND CONTINUES TO INTERACT ALOFT WITH AN UPPER LEVEL LOW CENTERED NEAR 18N70W. BOTH THE LOW-LEVEL CONVERGENCE AND UPPER LEVEL DIFFLUENCE ARE GENERATING AN AREA OF WIDELY SCATTERED MODERATE CONVECTION FROM 20N-23N BETWEEN 62W-68W. TOTAL PRECIPITABLE WATER IMAGERY ALSO SHOWS A HIGH CONTENT OF VERTICAL ATMOSPHERIC MOISTURE ALONG 60W AND THE ASSOCIATED SCATTERED SHOWERS AND ISOLATED TSTMS OCCURRING FROM 10N-20N BETWEEN 58W-61W. TROPICAL WAVE IS ANALYZED FROM 14N TO 21N ALONG 87W MOVING W AT 20 KT. THE WAVE EXHIBITS CYCLONIC TURNING OF THE LOW-LEVEL CLOUD FIELD WHICH HAS MOVED ONSHORE ACROSS THE YUCATAN THIS EVENING. PEAK DAYTIME HEATING AND INSTABILITY HAS GENERATED SCATTERED MODERATE CONVECTION OVER THE SW YUCATAN PENINSULA AND NORTHERN GUATEMALA FROM 16N-20N BETWEEN 89W-92W. ...ITCZ/MONSOON TROUGH... THE MONSOON TROUGH EXTENDS FROM THE AFRICAN COAST NEAR 10N13W TO 08N20W TO 13N31W 06N45W. THE INTERTROPICAL CONVERGENCE ZONE AXIS EXTENDS FROM 06N45W TO 09N61W. ISOLATED MODERATE CONVECTION IS FROM 06N-13N BETWEEN 15W-18W. SCATTERED MODERATE CONVECTION IS FROM 05N-08N BETWEEN 32W-40W...AND FROM 09N-12N BETWEEN 59W-62W. ...DISCUSSION... GULF OF MEXICO... WATER VAPOR IMAGERY INDICATES AN UPPER LEVEL LOW IS CENTERED OVER THE CENTRAL GULF NEAR 27N88W WHICH IS PROVIDING FOR AMPLE MIDDLE TO UPPER LEVEL LIFT ACROSS MUCH OF THE GULF BASIN THIS EVENING. WHILE A RELATIVELY WEAK SURFACE RIDGE EXTENDS ACROSS THE NE GULF ANCHORED BY A 1017 MB HIGH CENTERED OVER SOUTHERN ALABAMA...SOUTHERLY MOISTURE TRANSPORT AND INSTABILITY ACROSS PORTIONS OF THE WESTERN GULF ARE GENERATING ISOLATED SHOWERS AND TSTMS FROM 23N-29N BETWEEN 86W-97W. THE SURFACE HIGH IS EXPECTED TO SHIFT SOUTHEASTWARD OVER THE NEXT 24-36 HOURS AS AN AREA OF LOW PRESSURE DEVELOPS ACROSS THE WESTERN HIGH PLAINS OF THE U.S. CARIBBEAN SEA... AS MENTIONED ABOVE...A TROPICAL WAVE IS MOVING INTO THE CENTRAL CARIBBEAN AND CONTINUES TO INTERACT WITH AN UPPER LEVEL LOW CENTERED NEAR 18N70W. WHILE MOST OF THE ACTIVE CONVECTION IS LOCATED N OF 20N...SCATTERED SHOWERS AND ISOLATED TSTMS LOCATED WELL TO THE EAST OF THE WAVE AXIS ALONG 60W ARE EXPECTED TO IMPACT THE LESSER ANTILLES THIS EVENING INTO EARLY WEDNESDAY. FARTHER WEST...AN UPPER LEVEL ANTICYCLONE IS CENTERED OVER WESTERN CUBA NEAR 22N80W AND EXTENDS AN UPPER LEVEL RIDGE AXIS SOUTHWARD TO OVER PANAMA NEAR 10N80W. MOSTLY FAIR CONDITIONS ARE NOTED OVER MUCH OF THE WESTERN CARIBBEAN THIS EVENING...HOWEVER WITH AMPLE UPPER LEVEL DIFFLUENCE IN PLACE AND PEAK DAYTIME HEATING ACROSS CUBA...SCATTERED SHOWERS AND TSTMS ARE OCCURRING OVER MUCH OF INTERIOR CUBA BETWEEN 76W-84W. OTHERWISE...THE TROPICAL WAVE ALONG 87W IS FORECAST TO MOVE INLAND ACROSS BELIZE...THE YUCATAN PENINSULA...AND GUATEMALA DURING THE NEXT 12-24 HOURS. ATLANTIC OCEAN... TROPICAL STORM BRET CONTINUES TO RESIDE WITHIN A WEAKNESS OF THE SUBTROPICAL RIDGE ACROSS THE W ATLC THIS EVENING. AS BRET TRACKS NE OVER THE NEXT FEW DAYS THE SURFACE RIDGE AXIS IS EXPECTED TO RE-ESTABLISH ITSELF ALONG 26N THROUGH THE REMAINDER OF THE WEEK AND GRADUALLY SHIFT NORTHWARD TO 29N BY SATURDAY. FARTHER TO THE E-NE OF BRET THIS EVENING WATER VAPOR IMAGERY SHOWS A SHORTWAVE UPPER LEVEL TROUGH EAST OF BERMUDA ALONG 64W THAT SUPPORTS A 1013 MB LOW CENTERED NEAR 33N63W. THE LOW CONTINUES TO RAPIDLY PROGRESS EASTWARD WITH SCATTERED SHOWERS AND ISOLATED TSTMS OCCURRING OVER THE AREA FROM 30N-35N BETWEEN 53W-62W. THIS LOW IS FORECAST TO MOVE NE THEN MORE NORTH OVER THE NEXT 24 HOURS AS A STRONG 1034 MB AZORES HIGH IS CENTERED NEAR 39N29W. THIS HIGH CARRIES INFLUENCE ACROSS THE REMAINDER OF THE CENTRAL AND EASTERN TROPICAL ATLC N OF 18N WITH MOSTLY FAIR CONDITIONS AND A LARGE AREA OF NE TO E WINDS OF 15 TO 20 KT. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ HUFFMAN