000 AXNT20 KNHC 231744 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 205 PM EDT SUN JUL 23 2006 TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL AMERICA...THE GULF OF MEXICO...THE CARIBBEAN SEA...NORTHEASTERN 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...WEATHER OBSERVATIONS...RADAR... AND METEOROLOGICAL ANALYSIS. BASED ON 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 1715 UTC. ...TROPICAL WAVES... HIGH AMPLITUDE TROPICAL WAVE IS ALONG 37W S OF 22N WITH A 1013 MB LOW ALONG THE WAVE NEAR 15N MOVING W NEAR 15 KT. BROAD LOW LEVEL SIGNATURE CURVATURE WITH A WELL DEFINED LOW CENTER ARE OBSERVED ON VIS SATELLITE IMAGERY. WAVE IS EMBEDDED WITH AN AREA OF DENSE AFRICAN DUST...THUS ONLY ISOLATED SHOWERS ARE WITHIN THE ITCZ. TROPICAL WAVE IS ALONG 59W/60W S OF 14N MOVING W AROUND 15 KT. WAVE IS WEAK AND LOW AMPLITUDE AS OBSERVED ON SATELLITE IMAGERY. WAVE REMAINS EMBEDDED WITHIN AN AREA OF DENSE AFRICAN DUST...THUS NO ASSOCIATED SHOWERS/CONVECTION. TROPICAL WAVE IS ALONG 72W S OF 19N MOVING W NEAR 15 KT. THE WAVE SHOWS AN INVERTED-V CLOUD PATTERN ON VISIBLE SATELLITE IMAGERY. SCATTERED SHOWERS ARE JUST NORTH OF DOMINICAN REPUBLIC AND OVER LAKE MARACAIBO IN WESTERN VENEZUELA PROBABLY ASSOCIATED WITH THE WAVE. TROPICAL WAVE IS ALONG 97W/98W S OF 20N MOVING W 10 KT. WAVE IS ACCOMPANIED BY A BROAD SURFACE LOW PRESSURE AREA THAT IS PRODUCING CLOUDINESS...SHOWERS...AND A FEW THUNDERSTORMS OVER MUCH OF THE SOUTHWESTERN GULF OF MEXICO AND ADJACENT COASTAL AREAS. UPPER-LEVEL WINDS ARE EXPECTED TO BECOME A LITTLE MORE FAVORABLE DURING THE NEXT DAY OR TWO FOR SOME ADDITIONAL DEVELOPMENT TO OCCUR...IF THE SYSTEM REMAINS OVER WATER. AN AIR FORCE RESERVE RECONNAISSANCE AIRCRAFT IS SCHEDULED TO INVESTIGATE THE SYSTEM TOMORROW MORNING...IF NECESSARY. A CLUSTER OF MODERATE/ISOLATED STRONG CONVECTION HAS ALSO DEVELOPED BEHIND THE TROPICAL WAVE ON THE PACIFIC SIDE. ...ITCZ... ITCZ AXIS IS CENTERED ALONG 9N14W 9N25W 10N36W 10N40W 6N55W AND ACROSS PANAMA/COSTA RICA. WIDELY SCATTERED MODERATE CONVECTION IS WITHIN AROUND 100 NM ON EITHER SIDE OF THE AXIS WEST OF 30W. SCATTERED SHOWERS AND ISOLATED TSTMS ARE ELSEWHERE. ...DISCUSSION... GULF OF MEXICO... AN UPPER LOW IS IN THE E GULF NEAR 26N88W WITH AN UPPER TROUGH EXTENDING W TO INLAND OVER NE MEXICO JUST SOUTH OF BROWNSVILLE IN TEXAS. A LINE OF SHOWERS WITH EMBEDDED TSTMS LIES JUST SOUTH OF THE UPPER TROUGH ALONG 27N85W 26N90W 24N95W. A NARROW UPPER RIDGE EXTENDS ALONG THE N GULF COAST. SCATTERED MODERATE TO ISOLATED STRONG CONVECTION IS MOVING ACROSS SE LOUISIANA INTO THE GULF WATERS N OF 28N BETWEEN 88W-92W AHEAD OF A COLD FRONT THAT REMAINS INLAND OVER THE SE U.S. ANOTHER UPPER RIDGE COVERS S MEXICO...THE BAY OF CAMPECHE...THE YUCATAN PENINSULA AND NORTHERN CENTRAL AMERICA. CONVECTION IN THE BAY OF CAMPECHE IS ASSOCIATED WITH A TROPICAL WAVE ACCOMPANIED BY A BROAD SURFACE LOW PRESSURE AREA. SEE THE TROPICAL WAVES SECTION. AN UPPER HIGH IS LOCATED OFF THE E COAST OF FLORIDA COVERING THE SUNSHINE STATE AND THE GULF OF MEXICO E OF 83W. CARIBBEAN SEA... BROAD UPPER RIDGE EXTENDS FROM THE S GULF AND CENTRAL AMERICA INTO THE W CARIBBEAN W OF 83W WITH A SECOND WEAK UPPER RIDGE EXTENDING FROM AN UPPER HIGH OFF THE SE COAST OF FLORIDA TO OVER CUBA AND THE CAYMAN ISLANDS. AN UPPER TROUGH EXTENDS FROM THE CENTRAL ATLC ACROSS HISPANIOLA INTO THE SW CARIBBEAN. CONVECTION IN THE SW CARIBBEAN IS RELATED TO THE ITCZ AXIS OVER PANAMA AND COSTA RICA . UNDER AN ELY WIND FLOW...TYPICAL STREAMERS OR CLOUD LINES HAVE DEVELOPED ACROSS THE LESSER ANTILLES. STRONG TRADEWINDS CONTINUE ACROSS THE CARIBBEAN S OF 18N WITH GALE FORCE WINDS EXPECTED BY LATER TONIGHT. ATLANTIC OCEAN... UPPER HIGH IS LOCATED OFF THE E COAST OF FLORIDA DOMINATING THE W ATLC WITH THE UPPER RIDGE EXTENDING EWD S OF 32N TO 27N68W. EAST OF THE RIDGE...AN UPPER TROUGH IN THE CENTRAL ATLC EXTENDS FROM A WEAK UPPER LOW NEAR 28N62W SW INTO THE CARIBBEAN ACROSS HISPANIOLA. ANOTHER UPPER TROUGH IS DIPPING INTO THE E/CENTRAL ATLC N OF 23N FROM 30W-50W. BROAD UPPER RIDGE REMAINS IN CONTROL OF THE REMAINDER OF THE ATLC EXTENDING FROM WEST AFRICA ACROSS THE E ATLC. AT THE SURFACE...A 1028 MB HIGH PRESSURE IS LOCATED NEAR 33N53W WITH A RIDGE EXTENDING WWD TO SOUTH FLORIDA...WHERE THERE IS LESS SHOWER ACTIVITY THAN THE PREVIOUS DAYS. A BAND OF SCATTERED MODERATE/ISOLATED STRONG CONVECTION EXTENDS FROM 31N72W TO THE NORTH-CENTRAL COAST OF CUBA...AFFECTING ALSO THE NORTHERN BAHAMAS. SIMILAR CONVECTION IS FROM 28N-31N BETWEEN 77W-79W. ACCORDING TO THE 23/1500 UTC SAHARAN AIR LAYER FROM UW-CIMSS...A LARGE AREA OF DENSE AFRICAN DUST IS OVER THE E CARIBBEAN...GENERATING HAZY CONDITIONS AND LIMITING THE DEVELOPMENT OF ANY SIGNIFICANT CONVECTION OVER THE AREA. $$ GR