000 AXNT20 KNHC 111757 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 205 PM EDT SUN JUL 11 2010 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 1715 UTC... ...TROPICAL WAVES... TROPICAL WAVE EXTENDS FROM 09N-16N ALONG 16W MOVING W AT 10-15 KT. WHILE METEOSAT-9 VISIBLE IMAGERY SHOWS BROAD SCALE CYCLONIC TURNING OF THE LOW-LEVEL CLOUD FIELD IN THE VICINITY OF THE WAVE...UPPER AIR TIME SECTION ANALYSES FROM DAKAR SENEGAL INDICATES THE WAVE HAS NOT YET PASSED DAKAR. A 1010 MB LOW IS ANALYZED NORTH OF THE WAVE NEAR 20N18W THAT IS LIKELY THE NORTHERN VORTEX OF VORTICITY ASSOCIATED WITH THE WAVE. GLOBAL MODEL GUIDANCE INDICATE THE NORTHERN VORTEX OF THE WAVE WILL SLIDE SW OVER THE NEXT 24-36 HOURS AND THE ENERGY WILL BECOME ABSORBED INTO THE MAJORITY OF THE WAVE ENERGY LOCATED FARTHER EASTWARD. SCATTERED MODERATE CONVECTION COVERS A LARGE AREA FROM 05N-17N BETWEEN 12W-22W. TROPICAL WAVE IS ALONG 38W S OF 17W MOVING W AT 10-15 KT. HAVING BEEN DIFFICULT TO TRACK OVER THE PAST FEW DAYS...THE WAVE CONTINUES TO PROPAGATE WESTWARD BENEATH A FAIRLY EXTENSIVE SAHARAN AIR LAYER LOCATED ABOVE THE LOW-LEVEL AXIS VERTICALLY AND SURROUNDING THE WAVE LATITUDINALLY FROM 12N-22N OVER A LARGE PORTION OF THE CENTRAL TROPICAL ATLC. THE DRY AIR AND DUST ASSOCIATED WITH THE LAYER IS SUPPRESSING ALL DEEP ORGANIZED CONVECTION. HOWEVER...A FEW ISOLATED SHOWERS ARE OBSERVED ON SATELLITE IMAGERY NEAREST TO THE ITCZ AXIS AROUND 09N38W. TROPICAL WAVE EXTENDS FROM 19N71W TO 10N73W MOVING W AT 15-20 KT. TOTAL PRECIPITABLE WATER AND MOISTURE ASSOCIATED WITH THE WAVE CONTINUES TO STRETCH AS THE LOW-LEVEL AXIS APPROACHES AN MIDDLE TO UPPER LEVEL TROUGH EXTENDING OFF THE EASTERN U.S. COAST SOUTHWARD ACROSS THE BAHAMAS. NORTHERN ENERGY AND MOISTURE IS FEEDING INTO SCATTERED SHOWERS AND ISOLATED TSTMS NORTH OF THE TURKS AND CAICOS ISLANDS OVER THE W ATLC FROM 22N-26N BETWEEN 68W-75W. THE REMAINDER OF THE WAVE LOCATED SOUTH OF HISPANIOLA IN THE CARIBBEAN SEA IS UNDER THE INFLUENCE OF A SAHARAN AIR LAYER EVIDENT BY THE 07/1200 UTC SOUNDINGS AT SAN JUAN PUERTO RICO TO THE EAST OF THE WAVE AND KINGSTON JAMAICA TO THE WEST OF THE WAVE WHERE SAN JUAN REMAINS RELATIVELY DRY ALOFT AND KINGSTON REMAINS MOIST BELOW 600 MB. TROPICAL WAVE EXTENDS FROM 20N82W TO 08N83W MOVING W AT 15-20 KT. THE WAVE REMAINS EMBEDDED WITHIN A BROAD AREA OF DEEP LAYER MOISTURE THAT COVERS MUCH OF THE WESTERN CARIBBEAN EVIDENT IN TOTAL PRECIPITABLE WATER IMAGERY. THE COMBINATION OF THE WAVE AND AN UPPER LEVEL DIFFLUENT ZONE OVER CENTRAL AMERICA IS ENHANCING SCATTERED MODERATE AND ISOLATED STRONG CONVECTION FROM 09N-17N BETWEEN 80W-86W. TROPICAL WAVE IS OVER THE SW GULF OF MEXICO EXTENDING FROM 20N96W ACROSS SOUTHERN MEXICO TO 12N92W IN THE E PACIFIC REGION MOVING W NEAR 10-15 KT. THE WAVE CONTINUES TO DAMPEN OUT OVER PORTIONS OF MEXICO AND THE SW GULF OF MEXICO AS ENERGY AND MOISTURE TRAIL NORTHWESTWARD ALONG THE EASTERN MEXICO COAST TO 23N. SCATTERED MODERATE CONVECTION IS FROM 18N-23N BETWEEN 94W-99W. ...ITCZ... ITCZ AXIS IS CENTERED ALONG 09N17W 06N26W 09N38W 07N55W 10N70W. ASIDE FROM CONVECTION DISCUSSED ABOVE ASSOCIATED WITH THE TROPICAL WAVES...SCATTERED MODERATE AND ISOLATED STRONG CONVECTION IS FROM 04N-10N BETWEEN 22W-28W. SIMILAR CONVECTION IS FROM 02N-06N BETWEEN 43W-48W...AND WITHIN 150 NM NORTH OF THE AXIS BETWEEN 54W-60W. ...DISCUSSION... GULF OF MEXICO... THE NORTHERN EXTENSION OF A TROPICAL WAVE IS ANALYZED ACROSS THE SW GULF PRODUCING SCATTERED SHOWERS SW OF A LINE FROM LA PESCA MEXICO NEAR 24N98W TO CUIDAD DEL CARMEN MEXICO NEAR 19N92W. THIS ACTIVITY IS ENHANCED BY DIFFLUENCE ALOFT BETWEEN AN UPPER LEVEL RIDGE CENTERED OVER THE YUCATAN PENINSULA NEAR 18N89W...AND AN UPPER LEVEL TROUGH LOCATED OVER SW MEXICO. THE REMAINDER OF THE BASIN IS DOMINATED BY A SURFACE RIDGE ANCHORED BY A 1016 MB HIGH CENTERED NEAR 26N85W PROVIDING GENERALLY CLEAR SKIES AND FAIR WEATHER. HOWEVER...A SURFACE TROUGH ANALYZED AT 11/1500 UTC FROM JACKSONVILLE FLORIDA TO 30N86W IN THE NE GULF IS GENERATING SCATTERED SHOWERS AND TSTMS FROM 28N-30N BETWEEN 81W-89W. THE SURFACE RIDGE IS FORECAST TO REMAIN IN PLACE ALONG 26N THROUGH TUESDAY. CARIBBEAN SEA... A TROPICAL WAVE OVER THE WESTERN CARIBBEAN IS GENERATING AREAS OF SCATTERED SHOWERS AND TSTMS S OF 18N BETWEEN 78W-88W... INCLUDING INTERIOR PORTIONS OF CENTRAL AMERICA THIS AFTERNOON. THIS CONVECTION IS ALSO BEING ENHANCED BY UPPER LEVEL DIFFLUENCE IN ASSOCIATION WITH AN UPPER LEVEL ANTICYCLONE CENTERED OVER THE YUCATAN PENINSULA NEAR 18N89W. THE UPPER LEVEL HIGH EXTENDS A RIDGE AXIS SE OVER THE SW CARIBBEAN SEA TO NORTHERN COLOMBIA NEAR 09N75W. NORTHERLY FLOW ALOFT COVERS THE REMAINDER OF THE BASIN THAT IS ACCOMPANIED BY MODERATELY DRY AND STABLE AIR DUE TO THE PRESENCE OF A SAHARAN AIR LAYER. MANY OBSERVATIONS THIS MORNING ACROSS HISPANIOLA...PUERTO RICO...AND AS FAR SOUTH AS THE PARAGUANA PENINSULA IN NW VENEZUELA REPORTED DUST AND/OR HAZE. THIS COMBINATION IS KEEPING MUCH OF THE EASTERN HALF OF THE CARIBBEAN UNDER GENERALLY FAIR CONDITIONS. HOWEVER...A FEW ISOLATED SHOWERS ARE OCCURRING OVER THE LESSER ANTILLES E OF 63W. ATLANTIC OCEAN... A UPPER LEVEL SHORTWAVE TROUGH AXIS EXTENDS ALONG THE EASTERN U.S. SEABOARD TO NEAR NE FLORIDA NEAR 30N81W. THIS TROUGHING SUPPORTS A SURFACE TROUGH ANALYZED FROM 32N77W TO JACKSONVILLE FLORIDA AND INTO THE NE GULF OF MEXICO WITH SCATTERED SHOWERS WITHIN 90 NM EAST OF THE BOUNDARY. FARTHER SOUTHEAST...LOW-LEVEL MOISTURE AND CONVERGENCE ASSOCIATED WITH ENERGY FROM THE NORTHERN EXTENT OF A TROPICAL WAVE OVER THE CENTRAL CARIBBEAN IS GENERATING SCATTERED SHOWERS AND ISOLATED TSTMS FROM 22N-29N BETWEEN 68W-79W...INCLUDING THE BAHAMAS...AND TURKS AND CAICOS ISLANDS. OVER THE CENTRAL ATLC...AN UPPER LEVEL LOW IS CENTERED NEAR 31N59W THAT CONTINUES TO ENHANCE SCATTERED SHOWERS AND ISOLATED TSTMS FROM 26N-32N BETWEEN 58W-63W. A BROAD SURFACE RIDGE DOMINATES THE REMAINDER OF THE ATLC ANCHORED BY A 1030 MB HIGH CENTERED NEAR 38N47W PROVIDING MOSTLY FAIR CONDITIONS. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ HUFFMAN