000 AXNT20 KNHC 221026 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 805 AM EDT MON JUL 22 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 0952 UTC. ...TROPICAL WAVES... A TROPICAL WAVE IS OVER THE EAST TROPICAL ATLC WITH AXIS EXTENDING FROM 18N20W TO 08N21W. IT IS EMBEDDED WITHIN A MODERATE TO HIGH MOIST ENVIRONMENT AND ITS AXIS IS MOVING NEAR 10 KT. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS FROM 07N- 14N E OF 23W. ISOLATED MODERATE CONVECTION IS WITHIN 170 NM W OF THE AXIS S OF 18N. A TROPICAL WAVE IS MOVING ACROSS THE LESSER ANTILLES WITH A TILTED AXIS EXTENDING FROM 20N57W TO 13N64W AND MOVING NEAR 10 KT. THE WAVE AXIS IS EMBEDDED WITHIN A MOSTLY MODERATE MOIST ENVIRONMENT WITH PATCHES OF HIGH MOISTURE LYING OVER THE LEEWARD ISLANDS AND GRENADA. CONVECTIVE ACTIVITY HAS REDUCED TO RAINSHOWERS COINCIDING WITH THE REGIONS OF HIGHER MOISTURE OVER THE LEEWARD ISLANDS AND GRENADA. A SAL OUTBREAK SPREADS ACROSS THE ATLC TO JUST E OF THE WAVE AXIS. SAL DRY AIR ENTRAINMENT TO THE WAVE ENVIRONMENT IS HINDERING FURTHER CONVECTION AT THE TIME. ...ITCZ/MONSOON TROUGH... THE MONSOON TROUGH AXIS EXTENDS ACROSS AFRICA INTO THE E TROPICAL ATLC NEAR 14N17W AND CONTINUES ALONG 09N28W TO 07N35W. THE ITCZ AXIS EXTENDS FROM 07N35W TO 05N43W 04N51W. BESIDES THE CONVECTION ALREADY DISCUSSED ASSOCIATED WITH THE TROPICAL WAVE NEAR WEST AFRICA...NUMEROUS MODERATE CONVECTION IS FROM 06N-10N BETWEEN 26W-34W. ISOLATED MODERATE CONVECTION IS WITHIN 100 NM EITHER SIDE OF THE ITCZ AXIS BETWEEN 39W-52W. ...DISCUSSION... GULF OF MEXICO... AN UPPER LEVEL RIDGE CENTERED OVER NEW MEXICO EXTENDS OVER THE GULF W OF 89W WHILE THE AXIS OF A SHORT-WAVE TROUGH MOVES ALONG ALABAMA TO N OF 28N IN THE GULF. DIVERGENT FLOW FROM THESE TWO UPPER LEVEL FEATURES IS ENHANCING ISOLATED RAINSHOWERS AND TSTMS WITHIN 80 NM OF THE MISSISSIPPI AND ALABAMA COASTS. SE WIND FLOW IN THE RANGE OF 5-15 KT CONTINUES TO SPREAD OVER MOST OF THE GULF THIS MORNING. OTHERWISE...DRY AIR BEING ADVECTED FROM THE CARIBBEAN AS WELL AS DRY AIR IN THE MIDDLE LEVELS IS KEEPING THE REMAINDER GULF FREE OF CONVECTION. SURFACE RIDGING AND RETURN FLOW WILL PREVAIL ACROSS THE GULF DURING THE NEXT 48 HOURS. EXCEPT FOR THE NE GULF WHERE SOME SHOWERS MAY BE POSSIBLE...FAIR WEATHER IS EXPECTED FOR THE MOST PART DURING THIS TIME BEING SUPPORTED BY CONTINUOUS DRY AIR ADVECTION FROM THE CARIBBEAN. CARIBBEAN SEA... EXCEPT FOR THE EASTERN CARIBBEAN E OF 67W AND THE SOUTHERN CARIBBEAN S OF 14N...DRY AIR SPREADS ACROSS THE BASIN IN THE MIDDLE AND LOWER LEVELS AS DEPICTED IN TOTAL PRECIPITABLE WATER AND WATER VAPOR IMAGERY WHICH IS SUPPORTING FAIR WEATHER. NUMEROUS MODERATE CONVECTION IS OVER NICARAGUA AND EXTENDING OFF ITS COAST WITHIN 200 NM FROM 11N-15N. SCATTERED RAINSHOWERS ARE OVER COSTA RICA EXTENDING OFF ITS COASTLINE WITHIN 20 NM AND ISOLATED SHOWERS ARE S OF 11N IN THE REMAINDER SOUTHERN CARIBBEAN. THE CONVECTION IN THIS REGION IS ASSOCIATED WITH THE MONSOON TROUGH WHICH AXIS MOVES ACROSS COSTA RICA AND PANAMA TO NORTHERN COLOMBIA AND WITH BANKING OF HIGH LOW LEVEL MOISTURE BY STRONG EASTERLY TRADEWINDS. A TIGHT PRESSURE GRADIENT ACROSS MOST OF THE BASIN IS SUPPORTING TRADEWINDS OF UP TO 25 KT...LIGHTER TRADEWINDS UP TO 15 KT ARE OVER THE WESTERN CARIBBEAN. A TROPICAL WAVE IS MOVING ACROSS THE LESSER ANTILLES THIS MORNING AND WILL CONTINUE A W-NW TRACK TO PASS OVER PUERTO RICO LATE THIS MORNING...RAINSHOWERS ARE EXPECTED. THE WAVE WILL MOVE OFF THE WEST COAST LATE TONIGHT AND ENTER THE DOMINICAN REPUBLIC VERY EARLY ON TUESDAY. HISPANIOLA... DRY AIR IN THE LOWER AND MIDDLE LEVELS CONTINUE ACROSS LA HISPANIOLA THIS MORNING WHICH IS LIMITING ANY CONVECTIVE ACTIVITY. HOWEVER EARLY THIS AFTERNOON WEATHER CONDITIONS WILL START TO DETERIORATE AS A TROPICAL WAVE MOVES W-NW ACROSS PUERTO RICO. THE TROPICAL WAVE IS EXPECTED TO ENTER THE DOMINICAN REPUBLIC VERY EARLY ON TUESDAY. RAINSHOWERS ARE EXPECTED ACROSS THE ENTIRE ISLAND AS THE WAVE CONTINUES A W-NW TRACK TO EXIT THE COAST OF HAITI TUESDAY AFTERNOON. ATLANTIC OCEAN... PATCHES OF MODERATE LOW LEVEL MOISTURE AND UPPER LEVEL DIVERGENT FLOW IS SUPPORTING SCATTERED MODERATE CONVECTION WITH ISOLATED THUNDERSTORMS N OF 29N BETWEEN 52W-60W. A SURFACE TROUGH EXTENDS FROM 30N31W SW TO 27N35W AND NO CONVECTION IS ASSOCIATED WITH IT. OTHERWISE...SURFACE RIDGING IS ACROSS THE REMAINDER BASIN ANCHORED BY A PAIR OF 1022 MB HIGHS JUST N OF THE AREA OF DISCUSSION. BESIDES FOR 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