000 AXNT20 KNHC 222345 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 805 PM EDT TUE MAY 22 2012 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. ...TROPICAL WAVES... TROPICAL WAVE EXTENDS FROM 04N27W TO 12N25W MOVING W NEAR 15 KT. LOW-LEVEL CYCLONIC TURNING IS EVIDENT IN THE VICINITY OF THE WAVE AXIS BETWEEN 24W-29W. TOTAL PRECIPITABLE WATER IMAGERY INDICATES A LARGE AREA OF ENHANCED MOISTURE AROUND THE WAVE FROM 02N-13N BETWEEN 16W-27W WITH SAHARAN DUST WRAPPED AROUND THE NORTHERN PERIPHERY OF THE WAVE. WITH THE DUST INHIBITING ANY DEEP CONVECTION...ONLY ISOLATED SHOWERS ARE OCCURRING FROM 02N-09N BETWEEN 24W-29W. TROPICAL WAVE EXTENDS FROM 06N51W TO 13N50W MOVING W NEAR 15 KT. THE WAVE IS EMBEDDED WITHIN A BROAD AREA OF DEEP LAYERED MOISTURE BETWEEN 44W-53W AS EVIDENT IN TOTAL PRECIPITABLE WATER IMAGERY. THE WAVE REMAINS EMBEDDED WITHIN THE REGION OF THE ITCZ AND ON THE SOUTHERN PERIPHERY OF A STRONG CENTRAL ATLC RIDGE ANCHORED BY A 1027 MB HIGH CENTERED NEAR 32N52W. SCATTERED MODERATE CONVECTION IS FROM 07N-11N BETWEEN 48W-55W AND IS MORE LIKELY ASSOCIATED WITH THE ITCZ DESCRIBED BELOW. ...ITCZ/MONSOON TROUGH... THE INTERTROPICAL CONVERGENCE ZONE AXIS EXTENDS FROM 04N15W TO 06N27W TO 03N35W TO 08N51W TO 07N58W. ISOLATED MODERATE CONVECTION IS FROM 01N-05N BETWEEN 11W-23W. ...DISCUSSION... GULF OF MEXICO... AN UPPER LEVEL LOW IS CENTERED OVER NORTHERN ALABAMA NEAR 33N85W AND EXTENDS BROAD UPPER LEVEL TROUGHING SOUTHWARD TO A BASE NEAR 24N90W. WATER VAPOR IMAGERY INDICATES THAT MOST OF THE FLOW ALOFT IS EMBEDDED WITHIN DRY AIR AND STRONG SUBSIDENCE WHICH IS SUPPORTING A SURFACE RIDGE OVER MUCH OF THE GULF W OF 85W. THE RIDGE IS ANCHORED BY A 1017 MB HIGH CENTERED NEAR 24N96W. LIGHT ANTICYCLONIC WINDS ARE OCCURRING IN CLOSE PROXIMITY OF THE HIGH CENTER ITSELF...WHILE NORTHEAST WINDS IN THE RANGE OF 10 TO 15 KT ARE OCCURRING ON THE EASTERN PERIPHERY OF THE RIDGE BETWEEN 83W-94W. OVER THE EASTERN GULF AND FLORIDA PENINSULA...WEAK SURFACE TROUGHING PERSISTS EXTENDING FROM THE SW NORTH ATLC SOUTHWESTWARD TO A 1009 MB LOW CENTERED IN THE GULF OF HONDURAS IN THE NW CARIBBEAN SEA NEAR 17N86W. THIS SURFACE FEATURE... ALONG WITH THE ADVECTION OF MIDDLE TO UPPER LEVEL MOISTURE EAST OF THE TROUGH AXIS IS PROVIDING FOCUS FOR ISOLATED SHOWERS AND TSTMS OVER THE SOUTHERN FLORIDA PENINSULA AND SE GULF EAST OF A LINE FROM 28N81W TO THE NORTHERN YUCATAN PENINSULA NEAR 22N89W. THE SURFACE RIDGE IS FORECAST TO SLIDE EAST OF 90W AND WEAKEN GRADUALLY BY THURSDAY AS SOUTHERLY RETURN FLOW RE-ESTABLISHES ACROSS THE WESTERN GULF. WHILE THE RIDGE ERODES...THE LOW CENTERED IN THE NW CARIBBEAN SEA IS EXPECTED TO MOVE NORTHEAST AND IMPACT THE STRAITS OF FLORIDA LATE THURSDAY INTO FRIDAY AS IT CONTINUES INTO THE SW NORTH ATLC BY THE WEEKEND. CARIBBEAN SEA... MUCH OF THE CARIBBEAN BASIN W OF 64W IS UNDER THE INFLUENCE OF AN UPPER LEVEL RIDGE AXIS EXTENDING FROM AN UPPER LEVEL ANTICYCLONIC CIRCULATION CENTERED OVER SOUTHERN GUATEMALA NEAR 14N91W. THE UPPER LEVEL RIDGE AXIS EXTENDS E-NE TO 15N80W THEN NE TO BEYOND 20N70W. MUCH OF THE AREA ENCOMPASSED BENEATH THIS UPPER LEVEL RIDGING IS AN AREA OF MAXIMUM UPPER LEVEL DIFFLUENCE AS WELL AS OVERALL WEAK TROUGHING AT THE SURFACE. A SURFACE TROUGH IS ANALYZED FROM WESTERN CUBA NEAR 23N83W TO A 1009 MB LOW CENTERED NEAR 17N86W. SCATTERED SHOWERS AND TSTMS ARE OCCURRING MOSTLY TO THE EAST OF THE SURFACE TROUGH FROM 13N-23N BETWEEN 76W AND THE SURFACE TROUGH. ISOLATED SHOWERS ARE ALSO OCCURRING WITHIN 150 NM WEST OF THE SURFACE TROUGH AXIS... HOWEVER DRIER AIR ALOFT IS LIMITING OVERALL DEVELOPMENT THIS EVENING. THIS OVERALL SYNOPTIC SETUP FOR THE WESTERN CARIBBEAN IS UNLIKELY TO CHANGE OVER THE NEXT FEW DAYS AS GLOBAL MODELS SUGGEST AND THE FORECAST INDICATES THE LOW PRESSURE IN THE GULF OF HONDURAS IS TO DRIFT NORTHEASTWARD INTO THE FLORIDA STRAITS BY LATE THURSDAY INTO FRIDAY. E OF 75W...EAST-SOUTHEAST TRADES IN THE RANGE OF 15 TO 25 KT PERSIST AS SURFACE RIDGING EXTENDS SOUTHWESTWARD FROM THE CENTRAL ATLC ACROSS THE EASTERN CARIBBEAN. ISOLATED SHOWERS ARE NOTED ON SATELLITE IMAGERY OCCURRING ACROSS THE LESSER ANTILLES...PUERTO RICO...AND HISPANIOLA THIS EVENING. ATLANTIC OCEAN... WATER VAPOR IMAGERY INDICATES ADVECTION OF DEEP LAYERED TROPICAL MOISTURE DUE TO SOUTHWESTERLY FLOW ALOFT N OF 20N W OF 60W OVER THE SW NORTH ATLC. WITH THIS SOUTHWESTERLY FLOW ALOFT EXTENDING INTO THE NW CARIBBEAN SEA...SCATTERED SHOWERS AND WIDELY SCATTERED TSTMS ARE OCCURRING OVER MUCH OF THE SW NORTH ATLC THIS EVENING WITHIN 300 NM EITHER SIDE OF A LINE FROM 22N78W TO 32N66W. THE SURFACE TROUGHING ACROSS THE SW NORTH ATLC IS FORECAST TO PERSIST THROUGH THE REMAINDER OF THE WEEK AS A LOW OVER THE NW CARIBBEAN SEA DRIFTS NORTHEASTWARD INTO THE WESTERN SW NORTH ATLC OFFSHORE ZONES OVER THE WEEKEND. FARTHER EAST... THE CENTRAL AND EASTERN ATLC IS UNDER THE INFLUENCE OF A BROAD SURFACE RIDGE ANCHORED BY A 1027 MB HIGH CENTERED NEAR 32N52W. A COLD FRONT SKIRTS THE NORTHERN STRIP OF THE DISCUSSION AREA BETWEEN 30W-47W...ANALYZED FROM 32N30W TO 31N38W TO 32N47W. ISOLATED SHOWERS ARE OCCURRING WITHIN 90 NM EITHER SIDE OF THE FRONT. 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