000 AXNT20 KNHC 192358 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 805 PM EDT THU JUL 19 2007 TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL AMERICA...THE GULF OF MEXICO...THE CARIBBEAN SEA...NORTHERN SECTIONS OF SOUTH AMERICA...AND THE 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 2345 UTC. ...TROPICAL WAVES... ATLANTIC TROPICAL WAVE IS TITLED FROM 21N37W THROUGH A 1010 MB LOW NEAR 12N40W TO 4N41W MOVING W 15-20 KT. THIS IS A VERY LARGE AMPLITUDE WAVE CHARACTERIZED BY BROAD TURNING IN THE STRATOCUMULUS FIELD. THE ITCZ IS BEING PULLED NWD IN THE WAKE OF THE WAVE WITH SCATTERED MODERATE CONVECTION LIMITED TO A SMALL CLUSTER NEAR 9N40W. THE LATEST QUIKSCAT PASS...2044 UTC SUGGESTS THE SURFACE LOW HAS OPENED UP ALONG THE WAVE AXIS AND MAY BE DROPPED ON THE 0000 UTC ANALYSIS. STRONG EASTERN CARIBBEAN TROPICAL WAVE ALONG 66W/67W IS BECOMING ACTIVE WITH NUMEROUS MODERATE TO STRONG CONVECTION DEVELOPING OVER THE NORTHERN WINDWARD ISLANDS...ANTIGUA...ST MAARTEN AND ANGUILLA. SURFACE PRESSURES HAVE FALLEN 2-3 MB OVER THE PAST 24 HOURS OVER PUERTO RICO AND THE ADJACENT WINDWARD ISLANDS AND UPPER LEVEL ANTICYCLONIC OUTFLOW IS EXPANDING AND BECOMING BETTER DEFINED WITH TIME. IN ADDITION SOUTHERLY WINDS ARE NOTED OVER THE PORTIONS OF THE SOUTHERN LESSER ANTILLES. ADDITIONAL THUNDERSTORM ACTIVITY WAS OCCURRING OVER THE TROPICAL ATLANTIC FROM 18N-22N BETWEEN 61W-66W. TROPICAL WAVE IS ALONG 93W HAS MOVED W OF THE AREA WITH PRIMARY EFFECTS OVER THE EASTERN PACIFIC OCEAN...REFER TO MIATWDEP FOR ADDITIONAL DETAILS. ...THE ITCZ... ITCZ AXIS IS CENTERED ALONG 7N12W 10N25W 12N38W 9N44W 7N52W 9N61W. EXCEPT AS NOTED IN ASSOCIATION WITH THE TROPICAL WAVE ALONG 40W...SCATTERED MODERATE ISOLATED STRONG CONVECTION WAS NOTED WITHIN 60-90 NM OF THE ITCZ NEAR THE COAST OF AFRICA TO TO 15W. ISOLATED MODERATE CONVECTION WAS NOTED WITHIN 90 NM OF THE ITCZ BETWEEN 28W-33W. ...DISCUSSION... GULF OF MEXICO... A 1019 MB HIGH IS CENTERED JUST SOUTHEAST OF MOBILE ALABAMA WITH OVERALL FLOW OVER THE GULF FAIRLY WEAK IN NATURE. THUNDERSTORM ACTIVITY HAS DECREASED SIGNIFICANTLY FROM 24 HOURS AGO WITH SCATTERED MODERATE ISOLATED STRONG CONVECTION CONFINED TO THE W GULF FROM 24N TO THE TEXAS COAST AND W OF 95W. ADDITIONAL THUNDERSTORM ACTIVITY WAS NOTED ALONG THE UPPER TEXAS AND LOUISIANA COASTS. ISOLATED ACTIVITY WAS MOVING OFF THE SW COAST OF FLORIDA NEAR NAPLES AND OFF THE W COAST OF THE YUCATAN PENINSULA. IN THE UPPER LEVELS...AN UPPER LEVEL LOW CENTERED OVER W TEXAS NEAR 31N104W IS MOVING W 15 KT. IN ITS WAKE AN UPPER LEVEL HIGH CENTERED OVER THE NW GULF OF MEXICO NEAR 28N95W DOMINATED THE FLOW OVER MOST OF THE GULF. UPPER LEVEL LOWS OVER SOUTHERN ALABAMA AND THE NW CARIBBEAN NEAR 20N82W WERE PRODUCING CYCLONIC UPPER LEVEL FLOW OVER THE FAR NE AND SE GULF OF MEXICO AND W CUBA AND WERE IMPINGING UPON THE ANTICYCLONE FROM THE EAST. CARIBBEAN SEA... THE MOST ACTIVE WEATHER OVER THE CARIBBEAN WAS OCCURRING IN CONJUNCTION WITH THE WAVE ALONG 66W/67W. FOR ADDITIONAL DETAILS REFER TO THE TROPICAL WAVE SECTION ABOVE. ADDITIONAL CONVECTION WAS NOTED OVER HISPANIOLA...JAMAICA AND CUBA MAINLY DUE TO A COMBINATION OF DAYTIME HEATING...OROGRAPHIC LIFT AND COOLING ALOFT DUE AN UPPER LEVEL LOW NEAR 20N82W. TRADEWINDS HAVE LIGHTENED TO 15-20 KT ALONG THE COAST OF N COLOMBIA. AT THE UPPER LEVELS AN ANTICYCLONE WAS BECOMING ESTABLISHED IN THE VICINITY OF THE WAVE NEAR 16N64W WITH ANTICYCLONIC FLOW SPREADING OVER MOST OF THE CARIBBEAN E OF 73W...PORTIONS OF THE SW N ATLANTIC AND THE TROPICAL ATLC W OF 50W. UPPER LOW OVER THE NW CARIBBEAN NOTED ABOVE WAS MOVING W 10-15 KT. AN AREA OF STRONG UPPER LEVEL SUBSIDENCE WAS SITUATED BETWEEN THE 2 FEATURES GENERALLY IN THE AREA BETWEEN 73W AND 80W. UW-CIMSS ANALYSES INDICATED SOME RESIDUAL SAHARAN DUST IN THIS REGION. ATLANTIC OCEAN... BROAD CENTRAL ATLANTIC 1030 MB HIGH WITH A MEAN CENTER NEAR 38N41W DOMINATES THE AREA N OF 20N. IN THE UPPER LEVELS...A WELL DEFINED UPPER LEVEL LOW REMAINS NEAR 26N67W WITH A MUCH LARGER CIRCULATION NOTED NEAR 25N49W. A DEFORMATION AXIS EXISTS BETWEEN THE 2 FEATURES ALONG 31N62W 24N55W. THE EASTERN EXTENT OF AN UPPER LEVEL ANTICYCLONE OVER THE CARIBBEAN COVERS THE TROPICAL ATLC W OF 50W WITH A MUCH LARGER ANTICYCLONE OVER THE FAR E ATLANTIC NEAR 25N30W. AN AREA OF MODERATE TO STRONG SUBSIDENCE AND ACCORDING TO THE UW-CIMSS ANALYSES...SAHARAN DUST EXISTED FROM 10N-20N BETWEEN 40W-54W. THE TROPICAL WAVE ALONG 40W WAS TRAVERSING THIS AREA WITH THE SUBSIDENCE/SAHARAN AIR LAYER SUPPRESSING DEEP CONVECTION ALONG THE WAVE AXIS. $$ COBB