000 AXNT20 KNHC 241101 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 805 AM EDT WED JUL 24 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 1022 UTC. ...SPECIAL FEATURE... TROPICAL DEPRESSION FOUR HAS FORMED FROM THE TRPCL WAVE-LOW SYSTEM AND ITS CENTER IS LOCATED NEAR 13.9N 28.1W ABOUT 269 NM WSW OF THE CAPE VERDE ISLANDS. ITS PRESENT MOVEMENT IS WNW AT 17 KT WITH MAXIMUM SUSTAINED WINDS OF 30 KT AND A MINIMUM CENTRAL PRESSURE OF 1008 MB. THIS GENERAL MOTION IS EXPECTED TO CONTINUE DURING THE NEXT COUPLE OF DAYS. SOME SLIGHT STRENGTHENING IS EXPECTED DURING THE NEXT 48 HOURS...AND THE DEPRESSION IS FORECAST TO BECOME A TROPICAL STORM LATER TODAY OR TONIGHT. THE DEPRESSION IS EMBEDDED IN A HIGH MOIST ENVIRONMENT AT THE LOWER AND MIDDLE LEVELS SUPPORTING A CLUSTER OF MODERATE CONVECTION FROM 11N-15N BETWEEN 26W-30W AND SCATTERED MODERATE CONVECTION ELSEWHERE FROM 06N-15N BETWEEN 24W-34W. ...TROPICAL WAVES... A TROPICAL WAVE IS MOVING ACROSS CENTRAL CUBA AND CENTRAL CARIBBEAN WITH AXIS EXTENDING ALONG 24N76W TO 10N80W AND MOVING NEAR 5 KT. FOR THE MOST PART THE WAVE IS EMBEDDED IN A DRY ENVIRONMENT AND THERE IS NO CONVECTION ASSOCIATED WITH IT AT THE TIME. ...THE ITCZ/THE MONSOON TROUGH... THE MONSOON TROUGH AXIS EXTENDS ACROSS AFRICA INTO THE E TROPICAL ATLC NEAR 14N17W AND CONTINUES ALONG 14N23W...TROPICAL DEPRESSION FOUR...10N33W TO 08N36W. THE ITCZ AXIS EXTENDS FROM 08N36W TO 07N44W 05N53W. BESIDES THE CONVECTION ALREADY DISCUSSED ASSOCIATED WITH TROPICAL DEPRESSION FOUR...ISOLATED SHOWERS ARE WITHIN 100 NM EITHER SIDE OF THE AXES BETWEEN 35W- 52W. ...DISCUSSION... GULF OF MEXICO... SURFACE RIDGING DOMINATES THE GULF ANCHORED BY A 1016 MB HIGH NEAR 27N85W THAT IS PROVIDING RETURN FLOW IN THE RANGE OF 5-15 KT. MODERATE MOISTURE IS ACROSS THE FLORIDA PENINSULA...THE NE GULF N OF 27N E OF 85W AND THE BAY OF CAMPECHE. THIS MOISTURE COMBINED WITH UPPER LEVEL DIFFLUENCE FROM AN INVERTED TROUGH EXTENDING FROM THE SW GULF TO CENTRAL MEXICO AND A HIGH CENTERED OVER SOUTHERN MEXICO CONTINUE TO SUPPORT SCATTERED MODERATE CONVECTION OVER THE BAY OF CAMPECHE S OF 21N. OVER THE REMAINDER GULF...VERY DRY AIR AT THE LOWER AND MIDDLE LEVELS SUPPORTS FAIR WEATHER. THE HIGH IS EXPECTED TO PERSIST OVER THE GULF WATERS WITHIN THE NEXT 48 HOURS. RAINSHOWERS OVER THE NE AND SW GULF ARE EXPECTED DURING THIS PERIOD BUT THE REST OF THE BASIN WILL ENJOY FAIR WEATHER AS DRY AIR CONTINUES TO BE ADVECTED FROM THE CARIBBEAN INTO THE GULF. A COLD FRONT IS EXPECTED TO APPROACH THE NORTHERN GULF BY EARLY FRIDAY INCREASING THE CHANCES OF PRECIPITATION IN THIS REGION. CARIBBEAN SEA... A TROPICAL WAVE IS MOVING ACROSS CENTRAL CUBA AND THE CENTRAL CARIBBEAN THIS MORNING. FOR THE MOST PART THE WAVE IS EMBEDDED IN A DRY ENVIRONMENT AND THERE IS NO CONVECTION ASSOCIATED WITH IT AT THE TIME. A MODERATE MOIST ENVIRONMENT FOR THE MOST PART IS IN THE LOWER LEVELS OVER THE SOUTHERN CARIBBEAN S OF 16N W OF 79W. TRADEWINDS UP TO 25 KT ARE BANKING THIS MOISTURE TOWARD NICARAGUA AND COSTA RICA GENERATING SCATTERED MODERATE CONVECTION AND TSTMS OVER THE NORTHERN REGION OF THESE COUNTRIES AS WELL AS WITHIN 50 NM OF THE COASTLINE OF COSTA RICA. OVER THE W CARIBBEAN...SCATTERED SHOWERS ARE WITHIN 50 NM OFF THE HONDURAS COASTLINE. IN THE REMAINDER BASIN...DRY AIR IN THE LOWER AND MIDDLE LEVELS IS SUPPORTING FAIR WEATHER. OTHERWISE...TRADEWINDS UP TO 25 KT PREVAIL OVER THE CENTRAL- SOUTHERN CARIBBEAN WITH LIGHTER WINDS UP TO 15 KT ELSEWHERE. THE TROPICAL WAVE IS EXPECTED TO MOVE OFF THE WEST COAST OF CUBA VERY EARLY ON THURSDAY AND THEN OVER THE YUCATAN PENINSULA. HOWEVER...CONVECTIVE ACTIVITY IS NOT LIKELY OR WILL BE LIMITED AS THE WAVE WILL CONTINUE TO BE EMBEDDED IN A VERY DRY AIR ENVIRONMENT. HISPANIOLA... VERY DRY AIR IN THE LOWER AND MIDDLE LEVELS IS MAINTAINING A CONVECTIVE FREE ENVIRONMENT THIS MORNING. EXCEPT FOR AFTERNOON/EARLY EVENING SHOWERS ENHANCED BY SURFACE DAYTIME HEATING AND SUPPORTED BY THE BASE OF AN UPPER LEVEL TROUGH...FAIR WEATHER IS EXPECTED WITHIN THE NEXT 48 HOURS ACROSS THE ISLAND. ATLANTIC OCEAN... MODERATE MOISTURE IS ACROSS THE FLORIDA PENINSULA WITH HIGH MOISTURE EXTENDING TO THE W ATLC. THIS MOISTURE COMBINED WITH MIDDLE TO UPPER LEVEL DIFFLUENCE IS SUPPORTING SCATTERED A LINE OF SHOWERS AND TSTMS N OF 25N BETWEEN 73W-79W. A SURFACE TROUGH EXTENDS FROM A 1016 MB LOW NEAR 30N53W TO 27N56W 27N61W. A BROAD UPPER LEVEL LOW SUPPORTS THIS SURFACE FEATURE AS WELL AS SCATTERED SHOWERS AND ISOLATED TSTMS N OF 25N BETWEEN 51W-63W. ANOTHER SURFACE TROUGH EXTENDS FROM 30N34W TO 26N39W 24N45W WITH SCATTERED SHOWERS AND TSTMS AT ITS TAIL FROM 23N-26N BETWEEN 45W- 47W. OTHERWISE...SURFACE RIDGING IS ACROSS THE REMAINDER BASIN ANCHORED BY A 1018 MB HIGH NEAR 27N64W AND THE AZORES HIGH. BESIDES THE AREAS FORMERLY DISCUSSED...FAIR WEATHER IS ACROSS THE REMAINDER ATLC SUPPORTED BY DRY AIR AT THE LOWER AND MIDDLE LEVELS. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ RAMOS