TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 805 AM EDT TUE AUG 20 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 1015 UTC. ...TROPICAL WAVES... TROPICAL WAVE EXTENDS FROM A 1010 MB LOW CENTERED NEAR 12N29W TO 21N30W MOVING W AT 10-15 KT. THE WAVE IS EMBEDDED WITHIN A BROAD 700 MB TROUGH S OF 20N BETWEEN 23W-32W AND IS LOCATED WITHIN A BROAD LOW-LEVEL MONSOONAL GYRE FROM 09N-17N BETWEEN 23W-41W. NO SIGNIFICANT CONVECTION IS NOTED WITH THE WAVE AT THIS TIME. TROPICAL WAVE EXTENDS FROM 16N72W TO 24N70W MOVING W AT 10-15 KT. THE WAVE REMAINS EMBEDDED WITHIN A MOISTURE MAXIMUM ACCORDING TO TOTAL PRECIPITABLE WATER IMAGERY FROM 14N-23N BETWEEN 64W-70W. THE WAVE ALSO COINCIDES WITH A WEAK 700 MB TROUGH MOVING ACROSS THE NORTH-CENTRAL CARIBBEAN SEA AND PORTIONS OF THE SW NORTH ATLC. ISOLATED MODERATE CONVECTION IS FROM 21N-24N BETWEEN 68W-72W. TROPICAL WAVE EXTENDS FROM 17N91W TO 26N87W MOVING W AT 10-15 KT. THE WAVE COINCIDES WITH A WEAK 700 MB TROUGH AXIS EXTENDING FROM THE EASTERN GULF OF MEXICO TO OVER THE YUCATAN PENINSULA WITH THE STRONGEST RELATIVELY VORTICITY LOCATED OVER THE OPEN WATERS OF THE SE GULF. ISOLATED MODERATE CONVECTION IS OCCURRING FROM 22N-25N BETWEEN 87W-91W. ...ITCZ/MONSOON TROUGH... THE MONSOON TROUGH EXTENDS FROM THE AFRICAN COAST NEAR 18N17W TO 12N29W TO 09N33W TO 08N42W. THE INTERTROPICAL CONVERGENCE ZONE AXIS EXTENDS FROM 08N42W TO 08N54W. ISOLATED MODERATE CONVECTION IS WITHIN 240 NM SOUTH OF THE AXIS E OF 37W. ...DISCUSSION... GULF OF MEXICO... A MIDDLE TO UPPER LEVEL LOW IS CENTERED OVER NE MEXICO NEAR 25N101W AND IS PROVIDING THE WESTERN GULF WITH SOUTHERLY FLOW ALOFT AND ADVECTION OF MOISTURE NORTHWARD TO THE TEXAS AND LOUISIANA COAST THEN NORTHEASTWARD ON THE NORTHERN PERIPHERY OF AN UPPER LEVEL RIDGE AXIS EXTENDING FROM THE SW NORTH ATLC REGION FROM 31N82W TO 28N90W. OVERALL...THE SURFACE PRESSURE GRADIENT REMAINS WEAK AS A SURFACE TROUGH IS ANALYZED ACROSS THE NE GULF FROM 31N84W TO 28N86W AND A TROPICAL WAVE CONTINUES TO MOVE WEST ACROSS THE CENTRAL WATERS INTO THE WESTERN WATERS BY THIS AFTERNOON. ISOLATED SHOWERS AND TSTMS ARE OCCURRING WEST OF A LINE FROM THE LOUISIANA COAST NEAR 29N91W TO THE SOUTHERN MEXICO COAST NEAR 18N94W DUE PRIMARILY TO THE DIFFLUENCE ASSOCIATED WITH THE UPPER LEVEL LOW. FARTHER EAST...THE TROPICAL WAVE AND SURFACE TROUGH IS GENERATING WIDELY SCATTERED SHOWERS AND ISOLATED TSTMS E OF 91W THIS MORNING WITH MOISTURE AND CONVECTION SPREADING ACROSS THE FLORIDA STRAITS AND OFFSHORE WATERS BETWEEN THE FLORIDA PENINSULA AND THE BAHAMAS. OTHERWISE...E-SE WINDS PREVAIL AND ARE FORECAST TO REMAIN GENERALLY BELOW 20 KT FOR MOST OF THE WEEK AHEAD. CARIBBEAN SEA... AN UPPER LEVEL LOW IS CENTERED OVER THE NW CARIBBEAN NEAR 19N85W GENERATING WIDELY SCATTERED SHOWERS AND ISOLATED TSTMS N OF 17N BETWEEN 73W-85W...INCLUDING PORTIONS OF CUBA...THE CAYMAN ISLANDS...AND SOUTHERN APPROACHES TO THE WINDWARD PASSAGE. FARTHER EAST...AN UPPER LEVEL ANTICYCLONIC CIRCULATION IS CENTERED NEAR 14N68W AND INFLUENCES MUCH OF THE EASTERN AND CENTRAL CARIBBEAN WITH MODERATELY DRY AIR ALOFT AS NOTED ON WATER VAPOR IMAGERY. THE RIDGE AXIS EXTENDS ALONG 14N FROM OVER THE TROPICAL ATLC TO 78W. PRIMARILY LOW-LEVEL MOISTURE AND MARGINAL MIDDLE TO UPPER LEVEL DIFFLUENCE ARE GENERATING ISOLATED LOW-TOPPED ISOLATED SHOWERS AND TSTMS E OF 70W. A TROPICAL WAVE ALONG 71W AND A SURFACE TROUGH ANALYZED FROM 12N69W TO 17N65W REMAIN FOCAL POINTS FOR THIS SHOWER ACTIVITY WITH THE STRONGEST CONVECTION CURRENTLY IN THE VICINITY OF THE SOUTHERN COASTAL WATERS OF PUERTO RICO FROM 15N-18N BETWEEN 65W- 68W. HISPANIOLA... CURRENTLY EARLIER CONVECTION HAS DIMINISHED WITH ONLY A FEW REMAINING ISOLATED SHOWERS OCCURRING ACROSS PORTIONS OF THE ADJACENT COASTAL WATERS. WEST-SOUTHWESTERLY FLOW ALOFT REMAINS DOMINATE OVER THE ISLAND ON THE NORTHERN PERIPHERY OF AN UPPER LEVEL ANTICYCLONIC CIRCULATION CENTERED OVER THE EASTERN CARIBBEAN THIS MORNING. WITH MARGINAL MIDDLE TO UPPER LEVEL LIFT PRESENT AND A TROPICAL WAVE ALONG 71W...ISOLATED SHOWERS AND TSTMS ARE EXPECTED OVER THE NEXT 24 TO 36 HOURS WITH STRONGER SCATTERED CONVECTION EXPECTED TO INITIATE DURING THE AFTERNOON HOURS DUE TO PEAK DAYTIME HEATING AND INSTABILITY. ANY ACTIVITY THAT FORMS WILL LIKELY LAST INTO THE EVENING HOURS AND DIMINISH THEREAFTER. ATLANTIC OCEAN... A MIDDLE TO UPPER LEVEL ANTICYCLONIC CIRCULATION IS CENTERED OVER THE SW NORTH ATLC NEAR 32N68W THAT IS PROVIDING OVERALL STABLE CONDITIONS FOR THE SW NORTH ATLC W OF 60W. WATER VAPOR IMAGERY INDICATES THIS AREA REMAINS DRY ALOFT WITH SATELLITE IMAGERY INDICATING ISOLATED LOW-TOPPED SHOWERS OCCURRING PRIMARILY S OF 28N W OF 72W...AND MORE CONCENTRATED ACTIVITY OVER THE OFFSHORE AND COASTAL WATERS BETWEEN THE BAHAMAS AND FLORIDA PENINSULA INCLUDING THE FLORIDA STRAITS THIS MORNING. OTHERWISE...A 1020 MB HIGH CENTERED NEAR 33N70W IS FURTHER PROVIDING OVERALL FAIR CONDITIONS FOR MUCH OF THE WESTERN ATLC. FARTHER EAST...A MIDDLE TO UPPER LEVEL LOW IS CENTERED NEAR 27N54W THAT REMAINS EMBEDDED WITHIN DRY AIR ALOFT AND CONTINUES TO BE A RATHER BENIGN FEATURE. FINALLY...THE REMAINDER OF THE CENTRAL AND EASTERN ATLC IS UNDER THE INFLUENCE OF A SURFACE RIDGE ANCHORED BY A 1021 MB HIGH CENTERED NEAR 33N36W. FOR ADDITIONAL INFORMATION PLEASE VISIT WWW.HURRICANES.GOV/MARINE $$ HUFFMAN
Posted on: Tue, 20 Aug 2013 17:15:10 +0000
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