000 AXNT20 KNHC 281736 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 205 PM EDT TUE JUL 28 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 1645 UTC. ...TROPICAL WAVES... A TROPICAL WAVE IS ALONG 22W S OF 24N MOVING W NEAR 10 KT. THIS WAVE IS EMBEDDED WITHIN A VERY BROAD LOW/MID LEVEL CYCLONIC ROTATION WITH A WEAKENING 1012 MB LOW SW OF THE CAPE VERDE ISLANDS NEAR 15N27W AS INDICATED BY QUIKSCAT. THIS WAVE IS AT THE LEADING EDGE OF A MOISTURE MAXIMUM AS INDICATED BY TOTAL PRECIPITABLE WATER IMAGERY. ANY CONVECTION IS ASSOCIATED WITH THE ITCZ. A TROPICAL WAVE IS ALONG 49W/50W S OF 17N MOVING W 10-20 KT. THIS WAVE COINCIDES WITH A APEX OF A MOISTURE MAXIMUM BASED ON THE TOTAL PRECIPITABLE WATER PRODUCT. SCATTERED SHOWERS ARE FROM 11N-15N BETWEEN 49W-53W. A TROPICAL WAVE IS ALONG 75W/76W S OF 19N MOVING W NEAR 25 KT. VISIBLE SATELLITE IMAGERY INDICATES A BROAD INVERTED V CURVATURE THAT COVERS MOST OF THE CARIBBEAN. HOWEVER...DUE TO DRY STABLE AIR THAT ALSO COVERS MUCH OF THE CARIBBEAN...NO SHOWERS OR CONVECTION IS IN THE AREA. ...ITCZ... THE ITCZ AXIS IS CENTERED ALONG 15N16W 11N24W 10N35W 11N50W INTO SOUTH AMERICA NEAR 9N61W. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS WITHIN 60 NM OF THE ITCZ FROM 29W-34W. CLUSTERS OF SCATTERED MODERATE CONVECTION ARE FROM 9N-14N E OF 26W TO INLAND OVER W AFRICA AND FROM 7N-10N BETWEEN 31W-40W. ...DISCUSSION... GULF OF MEXICO... A RATHER BENIGN UPPER LOW IS ALONG THE COAST OF MEXICO NEAR TAMPICO GENERATING ISOLATED SHOWERS/THUNDERSTORMS WITHIN 60 NM ALONG THE COAST FROM TAMPICO TO LAGUNA MORALES. AN UPPER LEVEL TROUGH IS OVER THE E GULF WITH AN AXIS EXTENDING ACROSS THE FLORIDA PENINSULA TO 23N82W AND CONTINUING W TO THE REMNANTS OF AN UPPER LEVEL LOW NEAR 26N89W. ATMOSPHERIC LIFT IN MOIST SWLY FLOW ALOFT IS MOSTLY OVER THE W ATLC COMBINED WITH THE ATMOSPHERIC INSTABILITY TO THE E OF THE UPPER LEVEL TROUGH AXIS ARE SUPPORTING SCATTERED SHOWERS/ISOLATED THUNDERSTORMS OVER THE FAR SE GULF FROM THE FLORIDA KEYS TO OVER CUBA E OF 83W THROUGH THE STRAITS OF FLORIDA INTO THE W ATLC. ACROSS THE N GULF WATERS...UPPER LEVEL MOISTURE STREAMING SE W OF THE UPPER LEVEL RIDGE IS SUPPORTING ISOLATED SHOWERS MAINLY INLAND WITH A FEW MOVING OVER THE IMMEDIATE COASTAL WATERS FROM PANAMA CITY FLORIDA TO THE LOUISIANA/TEXAS BORDER. THE SURFACE RIDGE EXTENDS FROM THE ATLC OVER THE E HALF OF THE GULF AND IS EXPECTED TO CHANGE LITTLE OVER THE NEXT COUPLE OF DAYS. CARIBBEAN SEA... THE UPPER TROUGH OVER THE E GULF OF MEXICO IS DRAWING UPPER LEVEL MOISTURE S ACROSS CUBA TO THE GULF OF HONDURAS GENERATING SCATTERED SHOWERS/ISOLATED THUNDERSTORMS MAINLY N OF 19N FROM 76W-85W. ACROSS MUCH OF THE CENTRAL AND E CARIBBEAN...DEEP LAYER DRY AIR IS SUPPORTING MOSTLY FAIR WEATHER. FRESH TO STRONG EASTERLY TRADE WINDS MAINLY E OF THE TROPICAL WAVE ARE GENERATING ISOLATED FAST MOVING SHOWERS S OF 15N TO OVER THE WINDWARD ISLANDS. SIMILARLY...THE LOW LEVEL CONVERGENT FLOW OVER THE SW CARIBBEAN IS ENHANCING SCATTERED SHOWERS/ISOLATED THUNDERSTORMS FROM 12N-16N W OF 80W TO INLAND OVER NICARAGUA AND THE FAR NE HONDURAS. ATLANTIC OCEAN... AN UPPER LEVEL TROUGH OVER THE E GULF OF MEXICO EXTENDS OVER THE W ATLC W OF 76W AND COUPLED WITH AN UPPER RIDGE N OF THE TURKS AND CAICOS IS PROVIDING UPPER DIFFLUENCE TO GENERATE SCATTERED SHOWERS/ISOLATED THUNDERSTORMS WITHIN 90/120 NM OF LINE FROM THE FLORIDA COAST NEAR FORT LAUDERDALE TO BEYOND 32N75W AND S INTO THE STRAITS OF FLORIDA. AN UPPER LEVEL LOW IS CENTERED IN THE CENTRAL ATLC NEAR 30N55W GENERATING SCATTERED SHOWERS AND POSSIBLE ISOLATED THUNDERSTORMS WITHIN 60/75 NM OF LINE FROM 27N56W TO 30N54W. THE REMAINDER OF THE CENTRAL AND E ATLC ARE DOMINATED BY DRY STABLE AIR AND THEREFORE UNDER FAIR WEATHER. THE ENTIRE ATLC BASIN IS ALSO DOMINATED BY A SURFACE RIDGE ANCHORED BY A 1027 MB HIGH NEAR 34N57W. $$ WALLACE