000 AXNT20 KNHC 121035 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 805 AM EDT SAT JUL 12 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 1030 UTC. ...TROPICAL WAVES... TROPICAL WAVE CAME OFF THE WEST AFRICAN COAST ENGULFED BY THE SAHARAN AIR LAYER EARLIER THIS MORNING. THE SOUTHERN PORTION OF THE WAVE IS EMBEDDED IN THE MONSOON TROUGH WHICH IS SUPPORTING A CLUSTER OF MODERATE/STRONG CONVECTION AND TSTMS SE OF THE AXIS FROM 8N-12N E OF 19W. TROPICAL WAVE IS OVER THE CENTRAL ATLC JUST N OF THE ITCZ WITH AXIS EXTENDING FROM 19N43W TO 9N44W MOVING W AT 20-25 KT. THE WAVE IS COMPLETELY EMBEDDED IN THE DRY SAHARAN AIR LAYER WHICH IS HINDERING DEVELOPMENT OF DEEP CONVECTION AT THE TIME. TROPICAL WAVE IS LOCATED OVER THE CENTRAL CARIBBEAN WITH AXIS EXTENDING FROM 20N74W TO 10N76W MOVING W AT 20 KT. DEEP LAYER MOISTURE IS ASSOCIATED WITH THE WAVE. HOWEVER...STRONG DEEP LAYER ENVIRONMENTAL SHEAR IS INHIBITING THE DEVELOPMENT OF CONVECTION OVER CARIBBEAN WATERS. SCATTERED MODERATE CONVECTION AND TSTMS ARE OVER THE WINDWARD PASSAGE COINCIDING WITH AN AREA OF UPPER-LEVEL DIFFLUENCE. TROPICAL WAVE HAS MOVED ACROSS THE YUCATAN PENINSULA...NORTHERN CENTRAL AMERICA AND THE E PAC WATERS. ITS AXIS EXTENDS FROM 20N87W TO 9N90W MOVING W AT 20-25 KT. TOTAL PRECIPITABLE WATER IMAGERY SHOWS LIMITED MOISTURE ACROSS THIS REGION...THUS RESULTING IN A LACK OF ANY SIGNIFICANT DEEP CONVECTION OVER WATER AT THIS TIME. ...ITCZ/MONSOON TROUGH... THE MONSOON TROUGH EXTENDS FROM THE AFRICAN COAST NEAR 9N13W TO 7N18W. THE INTERTROPICAL CONVERGENCE ZONE AXIS EXTENDS FROM 7N18W TO 8N38W TO 6N57W. BESIDES THE CONVECTION ASSOCIATED WITH THE WAVES...SCATTERED MODERATE CONVECTION IS FROM 4N-10N BETWEEN 19W-32W. ...DISCUSSION... GULF OF MEXICO... SURFACE HIGH PRESSURE AND RIDGING CONTINUE TO DOMINATE THE GULF WATERS. IN THE MID-UPPER LEVELS...AN ANTICYCLONIC CIRCULATION CENTERED OVER MISSOURI EXTENDS A RIDGE AXIS TO THE NORTHERN AND WESTERN GULF TO SUPPORT A PAIR OF HIGHS...A 1020 MB HIGH NEAR 29N93W AND A 1019 MB HIGH NEAR 28N87W. A MODERATE MOIST AIRMASS HAS BEEN MOVING ACROSS THE GULF FROM THE SW N ATLC AND THE NW CARIBBEAN. A MID-LEVEL INVERTED TROUGH IS OVER THE EASTERN GULF AND SUPPORTS A SURFACE TROUGH ALONG WESTERN FLORIDA COASTAL WATERS FROM 30N84W TO 24N83W. MOISTURE AT THE LOW-MID LEVELS ALONG WITH TROUGHINESS ALOFT SUPPORT SCATTERED HEAVY SHOWERS AND TSTMS E OF 86W. SCATTERED SHOWERS EXTENDS INTO THE STRAITS OF FLORIDA. ISOLATED SHOWERS/TSTMS ARE WITHIN 90 NM OFF THE NORTHERN GULF COAST E OF 91W. OTHERWISE...THE SURFACE RIDGE IS FORECAST TO REMAIN ANCHORED ACROSS THE NORTHERN GULF WATERS THROUGH SATURDAY WITH LIGHT WINDS EXPECTED DURING THE WEEKEND. TWO TROPICAL WAVES WILL MOVE INTO THE BAY OF CAMPECHE IN THE NEXT TWO DAYS ENHANCING SHOWERS IN THE REGION. CARIBBEAN SEA... AN UPPER LEVEL LOW IS CENTERED OVER CENTRAL CUBA WHERE ALONG WITH DEEP LAYER MODERATE MOIST AIR ACROSS PORTIONS OF THE NW CARIBBEAN SUPPORT ISOLATED HEAVY SHOWERS AND TSTMS N OF 18N BETWEEN 78W-85W. TWO TROPICAL WAVES ARE MOVING ACROSS THE BASIN. REFER TO THE TROPICAL WAVES SECTION FOR DETAILS. DIFFLUENT FLOW ALOFT AND A TROPICAL WAVE STARTING TO MOVE ACROSS EASTERN CUBA SUPPORT SCATTERED SHOWERS AND TSTMS OVER THE WINDWARD PASSAGE AND ISOLATED SHOWERS ACROSS HISPANIOLA. IN THE SW CARIBBEAN...THIS SHOWER ACTIVITY IS BEING ENHANCED IN PART BY THE MONSOON TROUGH AXIS MOVING ACROSS COSTA RICA AND PANAMA. FRESH TO STRONG TRADES ARE FORECAST TO PERSIST THROUGH THE WEEKEND INTO EARLY NEXT WEEK. ...HISPANIOLA... CURRENTLY SCATTERED/ISOLATED SHOWERS ARE OCCURRING ACROSS THE ISLAND AS A TROPICAL WAVE MOVED ACROSS THE CENTRAL CARIBBEAN SEA. AN UPPER LEVEL LOW IS ALSO CENTERED TO THE W-NW OF THE ISLAND OVER CENTRAL CUBA AND IS PLACING HISPANIOLA WITHIN AN AREA OF UPPER LEVEL DIFFLUENCE THAT SUPPORTS THIS CONVECTION. AS THE WAVE PASSES TO THE WEST DURING THE NEXT 24 HOURS...THE UPPER LEVEL LOW IS ALSO EXPECTED TO DRIFT WESTWARD AND GRADUALLY WEAKEN IMPROVING CONDITIONS SLOWLY BY MONDAY. ATLANTIC OCEAN... A MIDDLE TO UPPER LEVEL TROUGH IS NOTED ON WATER VAPOR IMAGERY ALONG THE EASTERN U.S. SEABOARD THAT SUPPORTS A FRONTAL BOUNDARY N OF THE AREA OF DISCUSSION. AN ANTICYCLONIC CIRCULATION CENTERED OVER MISSOURI EXTENDS A RIDGE AXIS ACROSS FLORIDA AND PORTIONS OF THE SW N ATLC. THIS ENVIRONMENTAL PATTERN ALOFT IS FAVORING UPPER LEVEL DIFFLUENCE WHICH ALONG MOIST AIR ON THE REGION SUPPORT SCATTERED SHOWERS AND TSTMS N OF 22N W OF 77W AS WELL AS FROM 19N-23N BETWEEN 70W-75W. FARTHER EAST...A MID-UPPER LOW SUPPORT HEAVY SHOWERS AND TSTMS FROM 23N-31N BETWEEN 55W- 62W. THE REMAINDER OF THE CENTRAL AND EASTERN ATLC IS UNDER THE INFLUENCE OF A SURFACE RIDGE ANCHORED BY A 1030 MB HIGH CENTERED NEAR 38N47W. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ NR