000 AXNT20 KNHC 031758 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 205 PM EDT WED JUL 03 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 1715 UTC. ...TROPICAL WAVES... TROPICAL WAVE EXTENDS FROM 10N22W TO 20N20W MOVING W-NW AT 10-15 KT. THE WAVE REMAINS EMBEDDED WITHIN A POLEWARD SURGE OF MODERATE TO DEEP MOISTURE AS SHOWN ON TOTAL PRECIPITABLE WATER IMAGERY WITH GREATEST DEFINITION OF THE WAVE AXIS NOTED ON GLOBAL MODEL DATA AT THE 700 MB LEVEL. SATELLITE WINDS ALSO CONFIRM THE PRESENCE OF THE WAVE NEAR THIS LOCATION. CONVECTION REMAINS CONFINED TO AN AREA SOUTH OF THE AXIS WITH WIDELY SCATTERED MODERATE CONVECTION FROM 06N-10N BETWEEN 19W-26W AND LIKELY ENHANCED DUE TO CLOSE PROXIMITY OF THE MONSOON TROUGH AXIS AND INTERTROPICAL CONVERGENCE ZONE AXIS. TROPICAL WAVE EXTENDS FROM 06N42W TO 14N36W MOVING W-NW AT 15-20 KT. SATELLITE PRESENTATION SHOWS THE WAVE AND ASSOCIATED SHOWER AND TSTM ACTIVITY COINCIDES WITH A BROAD MID-LEVEL 700 MB TROUGH S OF 20N BETWEEN 35W-46W. NO SIGNIFICANT DEEP CONVECTION IS ASSOCIATED WITH THE WAVE AT THIS TIME DUE TO THE PRESENCE OF THE SAHARAN AIR LAYER AND DUST ON THE SURROUNDING NORTHERN PERIPHERY OF THE WAVE AXIS. TROPICAL WAVE EXTENDS FROM 15N62W TO 22N60W MOVING W AT 20 KT. THE WAVE REMAINS ASSOCIATED WITH A WEAK MID-LEVEL TROUGH PROGRESSING ACROSS THE NE CARIBBEAN SEA AND PORTIONS OF THE SW NORTH ATLC. NO SIGNIFICANT CONVECTION IS NOTED WITH THE WAVE AT THIS TIME. ...ITCZ/MONSOON TROUGH... THE MONSOON TROUGH EXTENDS FROM THE AFRICAN COAST NEAR 10N14W TO 09N21W. THE INTERTROPICAL CONVERGENCE ZONE AXIS EXTENDS FROM 09N21W TO 08N28W TO 12N36W...THEN RESUMES WEST OF THE TROPICAL WAVE NEAR 06N44W TO THE EQUATOR NEAR 49W. ISOLATED MODERATE CONVECTION IS FROM 05N-07N BETWEEN 44W-49W. ...DISCUSSION... GULF OF MEXICO... AN RELATIVELY AMPLIFIED UPPER LEVEL PATTERN DOMINATES OVER THE CONUS THIS AFTERNOON WITH A MIDDLE TO UPPER LEVEL LOW CENTERED OVER MISSOURI THAT IS PROVIDING MUCH OF THE GULF WITH MOIST SOUTHWESTERLY FLOW ALOFT. THE TROUGHING SUPPORTS A 1013 MB LOW CENTERED NEAR 27N91W WHICH IS ALONG A SURFACE TROUGH AXIS EXTENDING FROM SOUTHERN ALABAMA NEAR MOBILE BAY TO THE LOW CENTER THEN SOUTHWEST TO 24N95W. MOST OF THE ACTIVE WEATHER IS LOCATED WEST OF THIS BOUNDARY IN MAXIMIZED LOW-LEVEL MOISTURE CONVERGENCE AND MID-LEVEL DIFFLUENCE. SCATTERED SHOWERS AND TSTMS ARE OCCURRING BETWEEN THE WESTERN COAST OF THE FLORIDA PENINSULA ALONG 81W TO 90W...ALSO INCLUDING AN AREA WITHIN 120 NM OF THE YUCATAN PENINSULA COAST. THE LOW IS FORECAST TO DRIFT NORTHEASTWARD AND GRADUALLY DISSIPATE INLAND AS THE ASSOCIATED SURFACE TROUGHING DRIFTS WESTWARD THROUGH LATE FRIDAY. CARIBBEAN SEA... THE WESTERN CARIBBEAN SEA IS UNDER THE INFLUENCE OF AN UPPER LEVEL ANTICYCLONIC CIRCULATION CENTERED OVER THE GULF OF HONDURAS NEAR 18N88W WHICH IS PROVIDING PRIMARILY NORTHERLY FLOW. DIFFLUENCE IS MAXIMIZED BENEATH THIS UPPER LEVEL FEATURE WITH SCATTERED SHOWERS AND TSTMS OCCURRING N OF 16N W OF 82W. FARTHER SOUTH...THE MONSOON TROUGH IS ANALYZED ALONG 09N/10N AND IS PROVIDING FOCUS FOR SCATTERED SHOWERS AND TSTMS WITHIN 120 NM NORTH OF THE AXIS BETWEEN 79W-85W...INCLUDING INLAND PORTIONS OF COSTA RICA AND SOUTHERN NICARAGUA. EAST OF 70W...WATER VAPOR IMAGERY INDICATES DRIER AIR IS PROGRESSING WESTWARD FROM THE TROPICAL ATLC OVER PORTIONS OF THE EASTERN CARIBBEAN AND VENEZUELA WITH ONLY A FEW ISOLATED LOW-TOPPED SHOWERS OCCURRING BETWEEN 65W-78W...INCLUDING PUERTO RICO AND HISPANIOLA. FINALLY...A WEAK TROPICAL WAVE ALONG 61W IS FORECAST TO SKIRT THE NE CARIBBEAN AND PROVIDE FOCUS FOR ISOLATED SHOWER ACTIVITY THE NEXT COUPLE DAYS AS IT TRACKS WEST. HISPANIOLA... AN UPPER LEVEL LOW IS CENTERED N-NW OF THE ISLAND NEAR 23N72W AND EXTENDS AN UPPER LEVEL TROUGH AXIS S-SE TO 16N69W. EAST- SOUTHEASTERLY TRADES CONTINUE TO ADVECT LOW-LEVEL MOISTURE AND ALONG WITH MID-LEVEL LIFTING DYNAMICS...THE ATMOSPHERE SUPPORTS ISOLATED SHOWERS CURRENTLY. AS THE AFTERNOON AND EVENING PROGRESS...AND DAYTIME HEATING PEAKS WITH MAXIMUM INSTABILITY... AREAL COVERAGE WITH CONVECTION IS EXPECTED TO INCREASE WITH SCATTERED SHOWERS AND TSTMS. THE ACTIVITY SHOULD DIMINISH BY LATE EVENING. ATLANTIC OCEAN... AN UPPER LEVEL LOW IS NOTED ON WATER VAPOR IMAGERY CENTERED NEAR 23N72W THAT IS PROVIDING PORTIONS OF THE SW NORTH ATLC WITH WIDELY SCATTERED SHOWERS FROM 16N-26N BETWEEN 67W-73W. THIS UPPER LEVEL FEATURE IS LOCATED ABOVE A SURFACE RIDGE ANCHORED BY A 1030 MB HIGH CENTERED NORTH OF BERMUDA NEAR 35N65W. THE RIDGE IS FORECAST TO MOVE VERY LITTLE THROUGH LATE SATURDAY WITH A TROPICAL WAVE ALONG 61W TRACKING WESTWARD ON THE SOUTHERN PERIPHERY OF THE RIDGE ACROSS THE NE CARIBBEAN SEA AND GREATER ANTILLES. OTHERWISE...THE REMAINDER OF THE CENTRAL AND EASTERN ATLC IS UNDER THE INFLUENCE OF SURFACE RIDGING ANCHORED BY A 1028 MB HIGH CENTERED SOUTH OF THE AZORES NEAR 35N30W. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ HUFFMAN