000 AXNT20 KNHC 200558 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 205 AM EDT SAT JUL 20 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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 0522 UTC. ...TROPICAL WAVES... TROPICAL WAVE IS OVER THE CENTRAL TROPICAL ATLC EXTENDING FROM 19N41W TO 10N43W AND MOVING W-SW NEAR 10 KT. THE WAVE AXIS LIES WITHIN A MODERATE MOIST ENVIRONMENT AS DEPICTED IN TOTAL PRECIPITABLE WATER IMAGERY. THE METEOSAT-9 SAL TRACKING IMAGERY SHOW THE WAVE IS BEING ENGULFED BY DRY AIR WITH SOME OF IT SPREADING OVER THE WAVE ENVIRONMENT WHICH IS HINDERING DEEP CONVECTION. TROPICAL WAVE EXTENDS FROM 19N76W TO 10N77W MOVING W NEAR 5 KT. THE WAVE AXIS LIES WITHIN A MODERATE MOIST ENVIRONMENT AS DEPICTED IN TOTAL PRECIPITABLE WATER IMAGERY. SCATTERED MODERATE CONVECTION IS WITHIN 150 NM W OF THE AXIS FROM 15N-17N. TROPICAL WAVE IS MOVING ACROSS CENTRAL AMERICA EXTENDING FROM 17N86W TO 07N86W MOVING W NEAR 5 KT KT. THE WAVE IS EMBEDDED WITHIN A HIGH MOIST ENVIRONMENT OVER THE W CARIBBEAN AND THE EAST PACIFIC WHILE THE PORTION OF THE WAVE OVER LAND IS WITHIN DRY AIR. SCATTERED MODERATED CONVECTION WITH ISOLATED THUNDERSTORMS ARE FROM 17N-19N BETWEEN 84W-88W AS WELL AS OVER NICARAGUA AND ITS COASTAL WATERS S OF 12N. ...ITCZ/MONSOON TROUGH... THE MONSOON TROUGH EXTENDS FROM THE WEST COAST OF AFRICA NEAR 18N16W TO 13N20W 06N25W. THE ITCZ BEGINS NEAR 06N25W AND CONTINUES ALONG 04N34W TO 07N41W THEN IT RESUMES WEST OF A TROPICAL WAVE ALONG 09N46W TO 06N58W. SCATTERED MODERATE CONVECTION IS FROM 06N-13N BETWEEN E OF 27W. ISOLATED MODERATE CONVECTION IS WITHIN 120 NM N OF THE ITCZ W OF 46W. ...DISCUSSION... GULF OF MEXICO... AN UPPER LEVEL TROUGH EXTENDS FROM THE LOWER MISSISSIPPI VALLEY INTO THE GULF W OF 87W. THIS IS SUPPORTING A SURFACE TROUGH THAT EXTENDS FROM THE FLORIDA PANHANDLE TO 30N86W 27N90W 25N93W TO 23N96W. AN UPPER LEVEL RIDGE AXIS EXTENDS E OF 87W INTO THE W CARIBBEAN. MODERATE MOISTURE AT THE LOWER LEVELS AND DIFFLUENCE ALOFT IS ENHANCING ISOLATED SHOWERS SE OF THE SURFACE TROUGH N OF 24N E OF 89W. CONTINUOUS RAINSHOWERS HAVE BEEN REPORTED ACROSS THE FLORIDA PANHANDLE. WINDS ACROSS THE BASIN RANGE FROM 5-15 KT. THE UPPER LEVEL DIFFLUENT PATTERN IS EXPECTED TO PREVAIL WITHIN THE NEXT 48 HOURS AND RAINSHOWERS CAN BE EXPECTED ACROSS THE GULF. MOISTURE ASSOCIATED WITH A SURFACE TROUGH CURRENTLY OVER THE BAHAMAS WILL ALSO BRING INCREASED ACTIVITY TO THE SE GULF OVER THE WEEKEND. CARIBBEAN SEA... UPPER LEVEL RIDGING COVERS MUCH OF THE WESTERN CARIBBEAN WHICH IS PROVIDING NORTHERLY FLOW ALOFT OVER THE WESTERN PART OF THE AREA DRAWING MOISTURE SOUTH FROM THE GULF OF MEXICO. TWO TROPICAL WAVES ARE ALSO IN THIS AREA...ONE MOVING ACROSS CENTRAL AMERICA AND THE OTHER ACROSS JAMAICA INTO THE SOUTHERN CARIBBEAN. THESE WAVES ARE LEADING TO SCATTERED RAINSHOWERS/ISOLATED THUNDERSTORMS N OF 16N W OF 78W. SIMILAR ACTIVITY IS ACROSS NICARAGUA AS WELL AS S OF 12N W OF 78W. THE REMAINDER OF THE BASIN IS UNDER MOSTLY FAIR CONDITIONS DUE TO DRY AIR ALOFT AROUND A WEAK AND BROAD UPPER LOW NEAR 11N71W. THE WAVE OVER CENTRAL AMERICA IS EXPECTED TO BE COMPLETELY OVER THE E PACIFIC WITHIN 24 HOURS WHILE THE SECOND TRAILING WAVE IS EXPECTED TO VANISH DUE TO INTERACTION WITH DRY AIR AT THE LOWER LEVELS. HISPANIOLA... DRY AIR IS ACROSS LA HISPANIOLA LIMITING ANY CONVECTIVE ACTIVITY EVEN THAT A DIVERGENT PATTERN IS ALOFT. A DRY AIR MASS WILL CONTINUE TO BRING FAIR WEATHER TO THE ISLAND UNTIL EARLY SUNDAY AFTERNOON WHEN CONDITIONS CAN START TO DETERIORATE DUE TO A SURGE OF LOW LEVEL MOISTURE. ATLANTIC OCEAN... A SURFACE TROUGH IS MOVING ACROSS THE BAHAMAS EXTENDING FROM 26N73W TO 22N77W AND GENERATING SLIGHT SHOWERS N OF 22N W OF 75W. SURFACE RIDGING IS ACROSS THE REMAINDER BASIN ANCHORED BY A 1024 MB HIGH NEAR 28N64W AND A 1023 MB HIGH NEAR 29N35W. BESIDES THE REGIONS FORMERLY MENTIONED...FAIR WEATHER IS ACROSS THE ATLC SUPPORTED BY DRY AIR AT THE LOWER LEVELS. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ NR