000 AXNT20 KNHC 200516 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 205 AM EDT FRI JUL 20 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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 0445 UTC. ...TROPICAL WAVES... TROPICAL WAVE IS TITLED FROM 18N38W 12N42W 4N45W MOVING W 15-20 KT. BROAD WAVE LOW LEVEL INVERTED-V CURVATURE COVERING THE AREA FROM 35N-48N. SCATTERED SHOWERS ARE WITHIN THE ITCZ. TROPICAL WAVE IS SLIGHTLY TILTED ALONG 20N64W 15N67W 9N67W MOVING WNW NEAR 15 KT. WAVE AMPLITUDE HAS INCREASED OVER THE PAST 24 HOURS WITH A INCREASE OF PRESSURE GRADIENT OVER THE N PORTION OF THE WAVE. THIS SYSTEM DOES HAVE SOME POTENTIAL FOR FURTHER DEVELOPMENT BUT IF IT DOES IT WILL BE SLOW TO OCCUR. HEAVY RAIN WITH EMBEDDED THUNDERSTORMS HAVE ALSO INCREASED COVERING THE AREA FROM 15N-24N BETWEEN 60W-66W INCLUDING THE LEEWARD/VIRGIN ISLANDS AND WILL BE MOVING OVER PUERTO RICO AND HISPANIOLA LATER TODAY. ...THE ITCZ... ITCZ AXIS IS CENTERED ALONG 8N12W 7N19W 12N35W 7N53W 11N61W. SCATTERED MODERATE/STRONG CONVECTION IS MOVING OFF AFRICA WITHIN 90/120 NM OF LINE FROM 9N16W TO WELL INLAND OVER GUINEA AFRICA NEAR 10N14W. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS WITHIN 90/120 NM OF THE AXIS E OF 17W TO JUST INLAND OVER SIERRA LEONE AFRICA. SCATTERED THUNDERSTORMS ARE WITHIN 150/200 NM S OF THE AXIS FROM 28W-42W. ...DISCUSSION... GULF OF MEXICO... UPPER LEVEL HIGH IS ALONG THE W GULF COAST NEAR THE TEXAS/MEXICO BORDER WITH THE UPPER RIDGE COVERING THE GULF W OF 87W ENHANCING ISOLATED SHOWERS/THUNDERSTORMS W OF 94W. SHORTWAVE UPPER TROUGH EXTENDS FROM THE E COAST OF THE CAROLINAS ACROSS SE GEORGIA INTO THE FAR NE GULF ALONG THE WEST COAST OF FLORIDA. THE CUT-OFF UPPER LOW THAT REMAINS CLOSE TO THE CAYMAN ISLANDS COVERS THE GULF S OF 25N E OF 86W INTO THE W ATLC GENERATING ISOLATED SHOWERS/ THUNDERSTORMS OVER THE SAME AREA. OTHERWISE A WEAK SURFACE RIDGE REMAINS ACROSS THE GULF FROM THE W ATLC WITH A 1018 MB HIGH OFF THE SE LOUISIANA COAST NEAR 27N90W. CARIBBEAN SEA... THE AREA OF FOCUS TONIGHT REMAINS THE TROPICAL WAVE OVER THE E CARIBBEAN ESPECIALLY OVER THE LEEWARD/VIRGIN ISLANDS AS HEAVY RAINS WITH EMBEDDED THUNDERSTORMS AND WILL MOVING ACROSS PUERTO RICO AND HISPANIOLA LATER TODAY. OTHERWISE...AN ELONGATED CUT-OFF UPPER LOW REMAINS CENTERED CLOSE TO THE CAYMAN ISLANDS NEAR 19N83W COVERING THE AREA N OF 16N FROM 75W TO THE YUCATAN PENINSULA GENERATING SCATTERED SHOWERS/ISOLATED THUNDERSTORMS FROM N OF A LINE FROM BETWEEN JAMAICA AND E CUBA NEAR 19N78W TO THE YUCATAN PENINSULA NEAR 21N87W. BROAD UPPER HIGH IS CENTERED OVER THE FAR NE CARIBBEAN NEAR 17N64W COVERING THE E CARIBBEAN E OF 73W AND EXTENDS INTO THE W TROPICAL ATLC AND CENTRAL ATLC. DRY STABLE AIR IS TO THE E OF THE UPPER HIGH COVERING THE CARIBBEAN W OF 70W. THE ITCZ AXIS IN THE E PACIFIC REGION EXTENDS ACROSS PANAMA AND COSTA RICA GENERATING SCATTERED SHOWERS/THUNDERSTORMS S OF 10N FROM COLOMBIA TO COSTA RICA. MODERATE/STRONG EASTERLY TRADE WINDS CONTINUE ACROSS THE CARIBBEAN S OF 17N. ATLANTIC OCEAN... SHORTWAVE UPPER TROUGH EXTENDS FROM THE E COAST OF THE CAROLINAS ACROSS SE GEORGIA INTO THE FAR NE GULF ALONG THE WEST COAST OF FLORIDA AND EXTENDS OVER THE W ATLC N OF 27N W OF 77W. CUT-OFF UPPER LOW CLOSE TO THE CAYMAN ISLANDS COVERS THE SW ATLC S OF 25N W OF 75W GENERATING ISOLATED SHOWERS S OF 25N W OF 79W INTO THE STRAITS OF FLORIDA. AN UPPER LOW REMAINS IN THE NW ATLC NEAR 26N68W COVERING THE AREA N OF 22N FROM 62W-73W WITH A WEAKENING SURFACE TROUGH EXTENDING FROM 31N65W TO 25N67W. UPPER HIGH IN THE NE CARIBBEAN COVERS THE CENTRAL ATLC S OF 23N FROM 50W-68W JUST TO THE S OF THE UPPER LOW MENTIONED ABOVE. THIS IS ENHANCING THE THE HEAVY RAINS AND THUNDERSTORMS ASSOCIATED WITH THE TROPICAL WAVE OVER THE E CARIBBEAN. A CUT-OFF UPPER LOW IS CENTERED IN THE CENTRAL ATLC NEAR 25N49W COVERING THE AREA N OF 17N FROM 40W-55W WITH A VERY NARROW UPPER RIDGE BETWEEN THIS UPPER LOW AND THE UPPER LOW CENTERED NEAR 26N68W GENERATING SCATTERED SHOWERS/ISOLATED THUNDERSTORMS FROM 25N-31N BETWEEN 47W-64W. UPPER RIDGE EXTENDS OFF THE COAST OF AFRICA OVER THE E ATLC E OF 35W. THE LAST VISIBLE SATELLITE IMAGES OF THE YESTERDAY CONTINUE TO SHOW A LARGE AREA OF AFRICAN DUST OVER THE E ATLC S OF A LINE FROM MOROCCO NEAR 33N9W ALONG 30N24W 25N43W TO 21N55W WITH SOME CLEARING S OF 17N E OF 40W. THE REMAINDER OF THE ATLC CONTINUES TO BE DOMINATED BY A SURFACE RIDGE ANCHORED BY A 1033 MB HIGH CENTERED N OF THE REGION TO OVER THE N GULF OF MEXICO. $$ WALLACE