000 AXNT20 KNHC 281805 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 205 PM EDT WED AUG 28 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 AN AXIS ALONG 19N38W TO A 1012 MB LOW EMBEDDED IN THE MONSOON TROUGH TO 09N38W AND IS MOVING W NEAR 10 KT. TOTAL PRECIPITABLE WATER IMAGERY SHOW THE WAVE IS WITHIN A MODERATE TO HIGH MOIST ENVIRONMENT. ISOLATED MODERATE CONVECTION IS WITHIN 150 NM OF ITS AXIS. TROPICAL WAVE EXTENDS AN AXIS ALONG 23N52W TO 16N55W TO A 1015 MB LOW NEAR 11N54W AND IS MOVING W NEAR 15 KT. TOTAL PRECIPITABLE WATER IMAGERY SHOW THE NORTHERN AND SOUTHERN PORTIONS OF THE WAVE ARE WITHIN A MODERATE MOIST ENVIRONMENT. DRIER AIR IS NOTED IN THE CENTRAL PORTION OF THE WAVE WHERE CONVECTION IS BEING HINDERED. ISOLATED SHOWERS ARE WITHIN 100 NM EITHER SIDE OF THE WAVE AXIS FROM 19N-22N. SCATTERED MODERATE CONVECTION AND ISOLATED TSTMS ASSOCIATED WITH THE LOW PRESSURE ARE FROM 10N-13N BETWEEN 52W-55W. TROPICAL WAVE IS OVER THE FAR WESTERN CARIBBEAN SEA EXTENDING AN AXIS ALONG 21N86W TO 12N89W AND IS MOVING W NEAR 5 KT. TOTAL PRECIPITABLE WATER IMAGERY SHOW THE WAVE IS MOVING FROM A MODERATE MOIST ENVIRONMENT TO A DRIER ENVIRONMENT INLAND IN CENTRAL AMERICA AND THE YUCATAN PENINSULA. ISOLATED SHOWERS ARE WITHIN 100 NM EITHER SIDE OF THE WAVE AXIS. ...THE ITCZ/THE MONSOON TROUGH... THE MONSOON TROUGH AXIS EXTENDS FROM 12N16W TO 10N28W TO A 1012 MB LOW NEAR 13N38W TO 11N51W. BESIDES THE CONVECTION ASSOCIATED WITH THE TROPICAL WAVES ALREADY DISCUSSED...SCATTERED MODERATE CONVECTION AND TSTMS ARE FROM 04N-09N BETWEEN 26W-33W AND FROM 05N-11N BETWEEN 17W-26W. A CLUSTER OF SIMILAR CONVECTION IS FROM 10N-14N E OF 20W. ...DISCUSSION... GULF OF MEXICO... AN UPPER LEVEL INVERTED TROUGH EXTENDING FROM CENTRAL TEXAS TO JUST NORTH OF THE YUCATAN PENINSULA SUPPORTS A SURFACE TROUGH IN THE WESTERN GULF ALONG 27N96W TO 23N95W 19N93W. SCATTERED SHOWERS ARE WITHIN 100 NM EITHER SIDE OF THE AXIS. IN THE NE GULF...A MIDDLE LEVEL INVERTED TROUGH EXTENDING ACROSS FLORIDA TO THE YUCATAN PENINSULA SUPPORTS A WEAK SURFACE TROUGH ALONG 30N83W TO 27N85W. ISOLATED SHOWERS ARE N OF 27N E OF 87W. AN ELONGATED UPPER LEVEL LOW CENTERED OVER THE FLORIDA KEYS SUPPORTS A SURFACE TROUGH ALONG 27N79W TO 23N81W WHICH IS ENHANCING SCATTERED SHOWERS AND TSTMS FROM 24N-27N BETWEEN 79W- 82W. THE UPPER LOW IS ALSO ENHANCING SIMILAR CONVECTION IN THE SE GULF FROM 23N-24N BETWEEN 84W-86W. FAIR WEATHER IS ACROSS THE REMAINDER BASIN SUPPORTED BY MIDDLE LEVELS DRY AIR SUBSIDENCE. THE SURFACE TROUGH OVER THE WESTERN GULF IS EXPECTED TO DISSIPATE TONIGHT. A TROPICAL WAVE IS EXPECTED TO MOVE OVER THE BAY OF CAMPECHE EARLY ON THURSDAY GENERATING RAINSHOWERS WHILE A HIGH PRESSURE DEVELOPS OVER THE NE BASIN. ONCE DEVELOPED...HIGH PRESSURE OVER THE EASTERN GULF IS EXPECTED TO PERSIST UNTIL FRIDAY AFTERNOON. CARIBBEAN SEA... A TROPICAL WAVE IS OVER THE FAR WESTERN CARIBBEAN SEA EXTENDING AN AXIS ALONG 21N86W TO 12N89W. TOTAL PRECIPITABLE WATER IMAGERY SHOW THE WAVE IS MOVING FROM A MODERATE MOIST ENVIRONMENT TO A DRIER ENVIRONMENT INLAND IN CENTRAL AMERICA AND THE YUCATAN PENINSULA. ISOLATED SHOWERS ARE WITHIN 100 NM EITHER SIDE OF THE WAVE AXIS. A MODERATE TO HIGH MOIST ENVIRONMENT OVER THE WESTERN BASIN ALONG WITH MIDDLE LEVEL DIFFLUENCE SUPPORTS SCATTERED MODERATE CONVECTION AND TSTMS FROM 15N-20N BETWEEN 80W-85W. MIDDLE TO UPPER LEVEL DIFFLUENCE SUPPORTS SIMILAR CONVECTION OVER THE SOUTHERN BASIN FROM 10N-15N W OF 77W. A SURFACE TROUGH EXTENDS FROM 25N72W...ALONG EASTERN CUBA TO 15N77W. THIS TROUGH IS ENHANCING SCATTERED MODERATE CONVECTION AND TSTMS OVER THE CENTRAL AND EASTERN BAHAMAS AND ISOLATED SHOWERS AND TSTMS OVER SOUTHERN HAITI AND FROM 15N-18N BETWEEN 73W-77W. AN UPPER LEVEL TROUGH IS ENHANCING SHOWERS AND TSTMS ACROSS THE WINDWARD ISLANDS. DRY AIR IN THE LOWER AND MIDDLE LEVELS SUPPORTS FAIR WEATHER IN THE REMAINDER EASTERN CARIBBEAN. A TROPICAL WAVE IS EXPECTED TO ENTER THE EASTERN BASIN VERY EARLY ON THURSDAY AND MOVE ACROSS PUERTO RICO ON FRIDAY. HISPANIOLA... MODERATE MOISTURE IS ACROSS THE ISLAND AS DEPICTED IN TOTAL PRECIPITABLE IMAGERY. A SURFACE TROUGH EXTENDS FROM 25N72W...ALONG EASTERN CUBA TO 15N77W. THIS TROUGH IS ENHANCING ISOLATED SHOWERS AND TSTMS OVER SOUTHERN HAITI...WESTERN DOMINICAN REPUBLIC AND THE WINDWARD PASSAGE. SHOWERS MAY PERSISTS THROUGH EARLY THURSDAY WHEN A DRY AIRMASS IS EXPECTED TO MOVE ACROSS THE ISLAND. HOWEVER...WEATHER CONDITIONS START TO DETERIORATE LATE FRIDAY AS A TROPICAL WAVE APPROACHES THE ISLAND. THE TROPICAL WAVE IS EXPECTED TO MOVE ACROSS THE ISLAND ON SATURDAY. ATLANTIC OCEAN... AN ELONGATED UPPER LEVEL LOW CENTERED OVER THE FLORIDA KEYS SUPPORTS A SURFACE TROUGH ALONG 27N79W TO 23N81W WHICH IS ENHANCING SCATTERED SHOWERS AND TSTMS FROM 24N-27N BETWEEN 79W- 82W. A SURFACE TROUGH EXTENDS FROM 25N72W...ALONG EASTERN CUBA TO 15N77W. THIS TROUGH IS ENHANCING SCATTERED MODERATE CONVECTION AND TSTMS OVER THE CENTRAL AND EASTERN BAHAMAS. A STATIONARY FRONT ENTERS THE AREA OF DISCUSSION FROM 30N62W TO 28N66W TO 30N70W. THIS FRONTAL BOUNDARY BEING SUPPORTED BY AN UPPER LEVEL TROUGH IS ENHANCING SCATTERED SHOWERS N OF 28N BETWEEN 68W-76W AND SCATTERED MODERATE CONVECTION WITH EMBEDDED TSTMS N OF 28N BETWEEN 55W-60W. AN UPPER LEVEL TROUGH IS ENHANCING SHOWERS AND TSTMS ACROSS THE WINDWARD ISLANDS THAT EXTENDS EASTWARD TO 58W. BESIDES THE TROPICAL WAVES ALREADY DISCUSSED...SURFACE RIDGING AND FAIR WEATHER DOMINATE THE REMAINDER BASIN. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ NR