000 AXNT20 KNHC 030003 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 805 PM EDT WED JUL 02 2014 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 2345 UTC. ...SPECIAL FEATURE... TROPICAL STORM ARTHUR IS CENTERED NEAR 30.2N 79.2W AT 0000 UTC OR ABOUT 156 NM S-SE OF CHARLESTON SOUTH CAROLINA...MOVING N AT 6 KT. ESTIMATED MINIMUM CENTRAL PRESSURE IS 990 MB. MAXIMUM SUSTAINED WIND SPEED IS 60 KT WITH GUSTS TO 75 KT. A TURN TOWARD THE NORTH-NORTHEAST IS EXPECTED TONIGHT...FOLLOWED BY A TURN TOWARD THE NORTHEAST WITH AN INCREASE IN FORWARD SPEED ON THURSDAY. THE CORE OF ARTHUR IS EXPECTED TO SLOWLY APPROACH THE COASTS OF SOUTH AND NORTH CAROLINA DURING THE NEXT 24 TO 36 HOURS. ARTHUR IS EXPECTED TO BECOME A HURRICANE TONIGHT OR THURSDAY. NUMEROUS MODERATE CONVECTION IS FROM 27N-31N BETWEEN 75W-80W. SCATTERED MODERATE CONVECTION AND TSTMS ASSOCIATED WITH THE RAINBANDS OF ARTHUR ARE ELSEWHERE N OF 24N BETWEEN 72W-83W. PLEASE SEE THE LATEST INTERMEDIATE PUBLIC ADVISORY UNDER AWIPS/WMO HEADER MIATCPAT1/WTNT31 KNHC AND THE FULL FORECAST/ADVISORY UNDER AWIPS/WMO HEADER MIATCMAT1/WTNT21 KNHC FOR MORE DETAILS. ...TROPICAL WAVES... TROPICAL WAVE IS OVER THE CENTRAL ATLANTIC WITH AXIS EXTENDING FROM 22N37W TO 10N36W...MOVING W AT 20 KT. NO CONVECTION IS ASSOCIATED WITH THE WAVE AS SAHARAN DRY AIR IS IN THE WAVE ENVIRONMENT. TROPICAL WAVE IS LOCATED ABOUT 80 NM E-SE OF THE WINDWARD ISLANDS WITH AXIS EXTENDING FROM 19N55W TO 10N61W...MOVING W AT 15 KT. NO CONVECTION IS ASSOCIATED WITH THE WAVE AS SAHARAN DRY AIR IS IN THE WAVE ENVIRONMENT. TROPICAL WAVE IS LOCATED IN THE WESTERN CARIBBEAN WITH AXIS EXTENDING FROM 18N77W TO 10N81W...MOVING W AT 10-15 KT. ALTHOUGH MOST OF THE WAVE ENVIRONMENT IS EMBEDDED IN DEEP LAYER MOISTURE...STRONG DEEP LAYER ENVIRONMENTAL SHEAR IS HINDERING DEVELOPMENT OF CONVECTION E AND N OF THE AXIS. HOWEVER...UPPER LEVEL DIFFLUENCE AND LOW SHEAR SW OF THE WAVE IS SUPPORTING HEAVY SHOWERS AND TSTMS S OF 16N W OF 80W. TROPICAL WAVE IS MOVING ACROSS THE YUCATAN PENINSULA AND GUATEMALA WITH AXIS EXTENDING FROM 21N88W TO 11N92W...MOVING W AT 15-20 KT. SCATTERED SHOWERS AND ISOLATED TSTMS ARE LOCATED IN THE TERRITORIES MENTIONED ABOVE. ...THE ITCZ/THE MONSOON TROUGH... THE MONSOON TROUGH EXTENDS FROM THE COAST OF AFRICA NEAR 10N14W TO 9N26W TO 7N34W. THE ITCZ BEGINS NEAR 7N35W AND CONTINUES ALONG 4N44W TO 4N51W. SCATTERED MODERATE CONVECTION IS FROM 4N- 11N BETWEEN 16W-26W. ...DISCUSSION... ...THE GULF OF MEXICO... A MID-UPPER LEVEL CYCLONIC CIRCULATION IS OVER THE WESTERN GULF SUPPORTING A 1013 MB LOW CENTERED NEAR 21N95W. MOISTURE ADVECTION FROM THE E GULF ASSOCIATED WITH TROPICAL STORM ARTHUR IN THE SW N ATLC IS FUELING SCATTERED SHOWERS AND TSTMS FROM 20N- 23N W OF 91W AND ISOLATED SHOWERS ELSEWHERE IN THE BAY OF CAMPECHE. A MID-LEVEL ELONGATED ANTICYCLONE FROM TEXAS TO PENSACOLA FLORIDA EXTENDING INTO THE NORTHERN GULF SUPPORTS A 1018 MB HIGH NEAR 27N93W. FARTHER EAST...A MID LEVEL DIVERGENT ENVIRONMENT SUPPORTS SCATTERED MODERATE CONVECTION AND ISOLATED TSTMS N OF 24N BETWEEN 85W-91W. EASTWARD...THE RAINBANDS OF TROPICAL ARTHUR SUPPORT HEAVY SHOWERS AND TSTMS ALONG THE WESTERN COAST OF FLORIDA AND ADJACENT WATERS. A TROPICAL WAVE IS EXPECTED TO ENTER THE BAY OF CAMPECHE TOMORROW MORNING...FOLLOWED BY ANOTHER WAVE ON SATURDAY. MODEL GUIDANCE INDICATE THE CONTINUATION OF SHOWERS IN THIS REGION THROUGH THAT PERIOD. A FRONTAL SYSTEM IS EXPECTED TO EXTEND ALONG THE NORTHERN GULF COASTLINE BY FRIDAY. ...THE CARIBBEAN SEA... A TROPICAL WAVE IS MOVING ACROSS THE WESTERN CARIBBEAN...SEE TROPICAL WAVES SECTION FOR DETAILS. IN THE UPPER LEVELS...A BROAD RIDGE COVERS THE WESTERN BASIN WHILE AN ELONGATED TROUGH EXTENDS INTO THE EASTERN CARIBBEAN FROM THE CENTRAL ATLC. EXCEPT FOR THE SW BASIN AND PORTIONS OF THE NW CARIBBEAN...DRY AIR ASSOCIATED WITH A SAHARAN AIRMASS CONTINUES TO MOVES ACROSS THE REGION WHICH ALONG STRONG DEEP LAYER ENVIRONMENTAL SHEAR INHIBIT THE DEVELOPMENT OF CONVECTION. REMNANTS SHOWERS ASSOCIATED WITH THE PASSAGE OF A TROPICAL WAVE ARE OVER SOUTHERN HISPANIOLA AND ADJACENT WATERS. BROAD HIGH PRESSURE OVER THE ATLC EXTENDS A RIDGE TO THE NORTHERN CARIBBEAN...THUS TIGHTENING THE PRESSURE GRADIENT AND SUPPORTING EASTERLIES OF 20-25 KT S OF 17N BETWEEN 66W-81W. A TROPICAL WAVE IS EXPECTED TO ENTER THE EASTERN CARIBBEAN WEDNESDAY MORNING. ...HISPANIOLA... THE PASSAGE OF A TROPICAL WAVE TODAY HAS LEFT LINGERING SHOWERS AND ISOLATED TSTMS OVER SOUTHERN HISPANIOLA. A SAHARAN AIRMASS IS EXPECTED TO MOVE ACROSS THE ISLAND THURSDAY WHICH WILL REDUCE THE POTENTIAL FOR SHOWERS. HAZY WEATHER AND LOW VISIBILITY ARE EXPECTED AS THIS DRY DUSTY AIR LAYER MOVES OVER THE ISLAND. ...THE ATLANTIC OCEAN... OVER THE SW N ATLC...TROPICAL STORM ARTHUR CONTINUES MOVING NORTHWARD WHILE IT IS ANTICIPATED FOR IT TO STRENGHTEN TO A HURRICANE TONIGHT OR THURSDAY. NUMEROUS MODERATE CONVECTION IS FROM 27N-31N BETWEEN 75W-80W. SCATTERED MODERATE CONVECTION AND TSTMS ASSOCIATED WITH THE RAINBANDS OF ARTHUR ARE ELSEWHERE N OF 24N BETWEEN 72W-83W. SEE THE SPECIAL FEATURES SECTION FOR MORE INFORMATION. FARTHER EAST...A SURFACE TROUGH IS ANALYZED FROM 38N68N TO 30N66W TO 26N66W WITH ISOLATED SHOWERS 100 NM EITHER SIDE OF IT. AN ELONGATED MID-UPPER LEVEL TROUGH BETWEEN 50W-65W SUPPORTS A STATIONARY FRONT EXTENDING FROM A 1020 MB LOW NEAR 30N55W TO 25N57W TO 23N62W. ISOLATED SHOWERS ARE WITHIN 80 NM EITHER SIDE OF THE FRONT. OTHERWISE...BESIDES THE TROPICAL WAVES DISCUSSED ABOVE...SURFACE PRESSURE AND RIDGING DOMINATE ELSEWHERE. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ NR