000 AXNT20 KNHC 030520 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 805 AM EDT FRI JUL 03 2009 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...METEOROLOGICAL ANALYSIS...WEATHER OBSERVATIONS...AND RADAR. BASED ON 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 0445 UTC. ...TROPICAL WAVES... A LARGE TROPICAL WAVE IS ALONG 33W/34W S OF 18N MOVING W NEAR 20 KT. THIS WAVE COINCIDES WITH A HIGH AMPLITUDE DEEP LAYER MOISTURE MAXIMUM OBSERVED ON TOTAL PRECIPITABLE WATER IMAGERY. SATELLITE IMAGERY INDICATES BROAD LOW-LEVEL CYCLONIC FLOW IN THE VICINITY OF THE WAVE AXIS. ISOLATED MODERATE CONVECTION IS FROM 3N-8N BETWEEN 32W-37W. A TROPICAL WAVE IS ALONG 53W S OF 16N MOVING W 15-20 KT. THIS WAVE COINCIDES WITH A DEEP LAYER MOISTURE MAXIMUM OBSERVED ON TOTAL PRECIPITABLE WATER IMAGERY. ISOLATED MODERATE CONVECTION IS W OF THE WAVE AXIS FROM 9N-13N BETWEEN 53W-58W. THIS CONVECTION IS BEING ENHANCED BY UPPER LEVEL DIFFLUENCE AROUND AN UPPER LEVEL LOW IN THE ERN CARIBBEAN. A TROPICAL WAVE IS ALONG 74W S OF 17N MOVING W 15-20 KT. POSITION IS BASED ON CONTINUITY. NO DEEP CONVECTION IS CURRENTLY ASSOCIATED WITH THIS WAVE. ...ITCZ... THE ITCZ AXIS IS CENTERED ALONG 13N16W 11N24W 7N36W AND TO THE NE S AMERICA COAST NEAR 5N51W. SCATTERED MODERATE CONVECTION IS FROM 9N-11N BETWEEN 16W-21W AND FROM 4N-8N BETWEEN 38W-41W. ...DISCUSSION... GULF OF MEXICO... ISOLATED SHOWERS/THUNDERSTORMS REMAIN ACROSS THE N CENTRAL AND E GULF OF MEXICO N OF 25N E OF 93W...AND FROM 22N-24N E OF 85 INTO THE STRAITS OF FLORIDA. UPPER LEVEL DIFFLUENCE BETWEEN AN UPPER LEVEL TROUGH EXTENDING DOWN THE ERN UNITED STATES INTO THE CENTRAL GULF TO NEAR 26N88W...AN UPPER LEVEL LOW OVER THE NW CARIBBEAN NEAR 20N83W...AND AN UPPER LEVEL RIDGE OVER THE WRN ATLC ALONG WITH MOIST SWLY FLOW ALOFT ARE SUPPORTING THE SHOWER ACTIVITY. UPPER LEVEL DIFFLUENCE BETWEEN AN UPPER LEVEL HIGH OVER MEXICO AND THE UPPER LEVEL LOW OVER THE WRN CARIBBEAN ARE SUPPORTING A LARGE CLUSTER OF NUMEROUS SHOWERS/THUNDERSTORMS OVER THE YUCATAN PENINSULA AND THE BAY OF CAMPECHE S OF 22N BETWEEN 89W-93W. THE REMAINDER OF THE NW GULF OF MEXICO IS UNDER A WEAK RIDGE WITH GENERALLY FAIR WEATHER AND LIGHT SE TO S WINDS. EXPECT THE RIDGE TO STRENGTHEN AND PERSIST OVER THE NEXT FEW DAYS. CARIBBEAN SEA... AN UPPER LEVEL LOW IS OVER THE NW CARIBBEAN NEAR 26N88W. ATMOSPHERIC INSTABILITY NEAR THE UPPER LOW IS SUPPORTING SCATTERED SHOWERS/THUNDERSTORMS ACROSS CUBA AND THE ADJACENT WATERS N OF 19N BETWEEN 75W-85W. AN UPPER LEVEL HIGH IS OVER THE SW CARIBBEAN NEAR 12N79W. UPPER LEVEL DIFFLUENCE BETWEEN THE UPPER LEVEL HIGH AND NELY FLOW ALOFT OVER THE E PACIFIC IS SUPPORTING SCATTERED SHOWERS/THUNDERSTORMS S OF 14N W OF 76W INCLUDING PORTIONS OF COLUMBIA...PANAMA...COSTA RICA...AND NICARAGUA. AN UPPER LEVEL RIDGE COVERS THE ERN CARIBBEAN BRINGING DEEP LAYER DRY AIR AND SUBSIDENCE. DUE TO THIS...THE REMAINDER OF THE ERN CARIBBEAN IS EXPERIENCING GENERALLY FAIR WEATHER DESPITE THE PRESENCE OF A TROPICAL WAVE. ELY TRADE WINDS OF 20 KT COVER THE MAJORITY OF THE CARIBBEAN REACHING 30 KT IN SOME AREAS...WITH THE HIGHEST NEAR THE COAST OF COLUMBIA. ATLANTIC OCEAN... UPPER LEVEL DIFFLUENCE BETWEEN AN UPPER LEVEL TROUGH EXTENDING DOWN THE ERN UNITED STATES INTO THE CENTRAL GULF AND AN UPPER LEVEL RIDGE OVER THE WRN ATLC CENTERED AROUND AN UPPER LEVEL HIGH NEAR 29N63W ALONG WITH MOIST SWLY FLOW ALOFT ARE SUPPORTING ISOLATED SHOWERS/THUNDERSTORMS ACROSS THE NW ATLC EXTENDING FROM THE ERN GULF N OF 27N W OF 74W. A 1016 MB SURFACE LOW IS IN THE CENTRAL ATLC AT THE EDGE OF THE DISCUSSION AREA NEAR 32N45W. SURFACE CONVERGENCE NEAR THIS LOW AS WELL AS UPPER LEVEL DIFFLUENCE TO THE E OF A SHORTWAVE UPPER LEVEL TROUGH WITH AXIS ALONG 44W ARE SUPPORTING SCATTERED SHOWERS N OF 27N BETWEEN 38W-45W. A BROAD SURFACE RIDGE COVERS THE REMAINDER OF THE ATLC BRINGING GENERALLY FAIR WEATHER. THE RIDGE IS ANCHORED BY A 1024 MB SURFACE HIGH NEAR 27N59W AND A 1026 MB HIGH NEAR 32N28W. A BROAD LOW/MID-LEVEL DRY SAHARAN AIR LAYER COVERS THE E ATLC S OF 25N E OF 55W LIMITING DEEP CONVECTION IN THIS AREA. OVER THE TROPICAL ATLC...AN UPPER LEVEL HIGH IS CENTERED NEAR 15N39W ENHANCING CONVECTION NEAR THE ITCZ. $$ WALTON