000 AXNT20 KNHC 230547 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 205 AM EDT FRI AUG 23 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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 0515 UTC. ...TROPICAL WAVES... TROPICAL WAVE EXTENDS FROM 06N51W TO 16N50W MOVING W AT 15 KT. THE WAVE REMAINS LOW-AMPLITUDE AND EMBEDDED WITHIN THE MONSOON TROUGH. CONVECTION REMAINS LIMITED WITH ONLY A FEW ISOLATED SHOWERS OCCURRING FROM 06N-13N BETWEEN 48W-53W. TROPICAL WAVE EXTENDS FROM 11N82W TO 22N84W MOVING W AT 5-10 KT. THE WAVE REMAINS WITHIN BROAD LOW-LEVEL...SURFACE TO 700 MB...TROUGHING LOCATED ACROSS THE WESTERN CARIBBEAN SEA WITH TOTAL PRECIPITABLE WATER IMAGERY INDICATING MAXIMUM VALUES GENERALLY BETWEEN 78W-86W. SCATTERED MODERATE AND ISOLATED STRONG CONVECTION IS FROM 10N-24N BETWEEN 78W-85W. ...ITCZ/MONSOON TROUGH... THE MONSOON TROUGH EXTENDS FROM THE AFRICAN COAST NEAR 15N17W TO 10N51W. THE INTERTROPICAL CONVERGENCE ZONE AXIS EXTENDS FROM 10N51W TO 08N59W. SCATTERED MODERATE CONVECTION IS FROM 12N-17N BETWEEN 15W-19W...AND FROM 09N-12N BETWEEN 19W-24W. A SURFACE TROUGH IS ANALYZED NORTH OF THE MONSOON TROUGH AXIS FROM 15N35W TO 19N36W AND IS LIKELY ANOTHER IMPULSE OF ENERGY OR TROPICAL WAVE THAT MOVED OFF OF AFRICA EARLIER IN THE WEEK. LOW-LEVEL CYCLONIC MOTION IS NOTED IN THE CLOUD FIELD SURROUNDING THE SURFACE TROUGH WITH ISOLATED MODERATE CONVECTION OCCURRING IN THE VICINITY OF 17N35W. ...DISCUSSION... GULF OF MEXICO... UPPER LEVEL DIFFLUENT FLOW IS NOTED ON WATER VAPOR IMAGERY OCCURRING OVER THE WESTERN GULF BETWEEN AN UPPER LEVEL LOW CENTERED OVER NORTHERN MEXICO NEAR 28N105W AND AN UPPER LEVEL RIDGE EXTENDING FROM OVER CENTRAL MEXICO TO THE WESTERN GULF NEAR 25N95W. MIDDLE TO UPPER LEVEL DIFFLUENCE IS GENERATING ISOLATED SHOWERS AND TSTMS OVER THE WESTERN GULF THIS EVENING WEST OF 95W. FARTHER EAST...AN UPPER LEVEL LOW IS CENTERED OVER THE YUCATAN CHANNEL NEAR 22N86W. THIS UPPER LEVEL FEATURE ALONG WITH A MID-LEVEL VORTICITY MAXIMUM OVER THE NE GULF NEAR 27N87W IS GENERATING SCATTERED SHOWERS AND WIDELY SCATTERED TSTMS N OF 23N BETWEEN 82W-88W. MOST OF THIS CONVECTIVE ACTIVITY IS FOCUSED IMMEDIATELY OFFSHORE OF THE FLORIDA PENINSULA FROM 25N-29N BETWEEN 82W-85W...AND IN THE VICINITY OF A SURFACE TROUGH ANALYZED FROM 27N-30N ALONG 87W. LOOKING AHEAD...GENERALLY E-SE WINDS ARE EXPECTED TO PREVAIL THROUGH THE UPCOMING WEEKEND AS A SURFACE RIDGE CONTINUES TO BE ANCHORED OVER THE SE CONUS AND SW NORTH ATLC. CARIBBEAN SEA... AN UPPER LEVEL LOW IS CENTERED OVER THE YUCATAN CHANNEL NEAR 22N86W AND ALONG WITH A TROPICAL WAVE ALONG 83W CONTINUES TO GENERATE SCATTERED SHOWERS AND TSTMS ACROSS THE WESTERN CARIBBEAN BETWEEN 76W-87W. THE STRONGEST CONVECTION AT THIS TIME IS LOCATED OFFSHORE OF NICARAGUA AND EASTERN HONDURAS IN THE VICINITY OF 14N82W. THE WAVE IS EXPECTED TO CONTINUE A SLOW WESTWARD MOVEMENT OVER THE NEXT 24 TO 48 HOURS BRINGING INCREASED PRECIPITATION CHANCES TO CENTRAL AMERICA AND THE NW CARIBBEAN WATERS OVER THE WEEKEND. TO THE SOUTH...THE MONSOON TROUGH IS ALONG 10N/11N EXTENDING FROM NORTHERN COLOMBIA WESTWARD INTO THE EAST PACIFIC REGION. ISOLATED SHOWERS AND TSTMS ARE OCCURRING WITHIN 150 NM EITHER SIDE OF THE AXIS...INCLUDING PORTIONS OF PANANA...COSTA RICA...AND NICARAGUA THIS EVENING. FINALLY...E-SE TRADES CONTINUE ACROSS THE EASTERN CARIBBEAN WITH AN UPPER LEVEL LOW CENTERED OVER PUERTO RICO NEAR 18N67W. ISOLATED SHOWERS ARE OCCURRING FROM 14N-20N BETWEEN 61W- 70W. HISPANIOLA... EARLIER EVENING CONVECTION HAS DIMINISHED WITH ONLY A FEW ISOLATED SHOWERS POSSIBLE THROUGH THE OVERNIGHT HOURS. AN UPPER LEVEL LOW IS CENTERED OVER PUERTO RICO NEAR 18N67W AND HISPANIOLA LIES ON THE WESTERN AND RELATIVELY DRIER SIDE OF THIS UPPER LEVEL FEATURE AS NOTED ON WATER VAPOR IMAGERY. THE UPPER LEVEL LOW IS EXPECTED TO DRIFT WESTWARD OVER THE NEXT 24 TO 48 HOURS AND PROVIDE A MORE FAVORABLE ATMOSPHERE FOR AFTERNOON AND EVENING CONVECTION. THESE ADDED MIDDLE TO UPPER LEVEL DYNAMICS ALONG WITH PEAK DAYTIME HEATING AND INSTABILITY WILL INITIATE AFTERNOON SHOWERS AND TSTMS. ANY ACTIVITY THAT FORMS WILL LIKELY LAST INTO THE EVENING HOURS AND DIMINISH THEREAFTER. ATLANTIC OCEAN... AN UPPER LEVEL RIDGE AXIS EXTENDS OVER THE FLORIDA PENINSULA EASTWARD TO 24N70W PROVIDING MUCH OF THE SW NORTH ATLC WITH NORTHWESTERLY FLOW ALOFT. WITH AN MID-LEVEL SHORTWAVE TROUGH PROGRESSING OFF THE MID-ATLC COAST...MOISTURE AND CLOUDINESS IS NOTED N OF 28N W OF 70W. WITHIN THE AREA...ISOLATED SHOWERS ARE POSSIBLE...HOWEVER A SURFACE RIDGE REMAINS THE DOMINATE SURFACE FEATURE ANCHORED BY A 1019 MB HIGH CENTERED NEAR 31N75W. FARTHER EAST...A MIDDLE TO UPPER LEVEL TROUGH AXIS EXTENDS FROM 32N54W SW TO 26N63W. THIS TROUGHING SUPPORTS A WEAK COLD FRONT ANALYZED FROM 32N55W TO 28N60W. A PRE-FRONTAL SURFACE TROUGH IS ANALYZED FROM 31N52W TO 26N62W WITH ISOLATED SHOWERS OCCURRING WITHIN 240 NM SOUTHEAST OF THE COLD FRONT. OTHERWISE...THE REMAINDER OF THE CENTRAL AND EASTERN ATLC IS UNDER THE INFLUENCE OF A SURFACE RIDGE ANCHORED BY A 1025 MB HIGH CENTERED S-SW OF THE AZORES NEAR 34N31W. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ HUFFMAN