000 AXNT20 KNHC 201749 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 205 PM EDT MON JUL 20 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 1715 UTC. ...TROPICAL WAVES... A TROPICAL WAVE IS ALONG 28W S OF 13N MOVING W NEAR 15 KT. EXAMINING THE UPPER AIR TIME SECTION ANALYSIS FROM DAKAR SENEGAL...IT APPEARS A LOW-LEVEL...700-850 MB...CYCLONIC CIRCULATION PASSED THROUGH DAKAR BEFORE 19/1200 UTC. WHILE THIS WAVE REMAINS EMBEDDED WITHIN THE ITCZ...SCATTERED MODERATE CONVECTION IS LOCATED WELL W OF THE WAVE AXIS FROM 4N-9N BETWEEN 31W-37W. A TROPICAL WAVE IS ALONG 46W S OF 18N MOVING W NEAR 18 KT. THIS WAVE COINCIDES WITH A DEEP LAYER MOISTURE MAXIMUM OBSERVED IN TOTAL PRECIPITABLE WATER IMAGERY. WHILE ON THE LEADING EDGE OF A DRY SAHARAN AIR TO THE EAST...DUST IS OBSERVED ON METEOSAT-9 VISIBLE IMAGERY E OF 45W. DUE TO THE PRESENCE OF THIS DRY AIR AND A CENTRAL ATLC SURFACE RIDGE HOLDING STRONG N OF 18N...NO SIGNIFICANT DEEP CONVECTION IS OCCURRING WITH THE WAVE. A TROPICAL WAVE IS ALONG 58W S OF 19N MOVING W NEAR 22 KT. THIS WAVE COINCIDES WITH A LOW TO MIDDLE LEVEL CYCLONIC TURNING IN SATELLITE CLOUD DRIFT WINDS AS WELL AS CYCLONIC TURNING DEPICTED ON AN EARLIER SCATTEROMETER PASS AROUND 20/1000 UTC. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS FROM 11N-16N BETWEEN 55W-61W. A HIGH AMPLITUDE TROPICAL WAVE EXTENDS FROM THE NW BAHAMAS NEAR 27N77W THROUGH ERN CUBA AND CENTRAL JAMAICA TO NWRN COLOMBIA NEAR 8N76W MOVING W NEAR 20 KT. THIS WAVE COINCIDES WITH A LARGE AREA OF MAXIMUM TOTAL PRECIPITABLE WATER ACROSS THE WRN CARIBBEAN AND PORTIONS OF THE SW NORTH ATLC. WITH A SHARP UPPER TROUGH LOCATED ACROSS THE NE GULF AND FLORIDA PENINSULA...THIS WAVE IS EXPECTED TO FRACTURE A SURFACE TROUGH TRACKING N-NW THROUGH WEDNESDAY WHILE THE REMAINING SRN PORTION OF THE WAVE CONTINUES WWD TOWARDS CENTRAL AMERICA. SCATTERED MODERATE CONVECTION IS HOWEVER LIMITED TO AN AREA S OF JAMAICA FROM 14N-17N BETWEEN 75W-79W. ...ITCZ... THE ITCZ AXIS IS CENTERED ALONG 14N17W 9N27W 7N31W 5N45W 5N48W 8N58W. SCATTERED MODERATE CONVECTION IS FROM 11N-16N BETWEEN 17W-22W. A CLUSTER OF SCATTERED MODERATE CONVECTION IS FROM 4N-9N BETWEEN 31W-37W. ...DISCUSSION... GULF OF MEXICO... A COLD FRONT EXTENDS ACROSS NE FLORIDA CONTINUING WWD AS A STATIONARY FRONT ALONG 29N TO NEAR NEW ORLEANS LOUISIANA. A PRE-FRONTAL TROUGH EXTENDS FROM JACKSONVILLE TO TAMPA FLORIDA AND INTO THE E GULF NEAR 26N84W. THESE FRONTS ARE ASSOCIATED AND SUPPORTED BY A SHARP UPPER LEVEL TROUGH THAT COVERS THE NE GULF AND FLORIDA PENINSULA DIPPING TO 24N. AS OBSERVED ON DOPPLER RADAR AND LIGHTNING DATA...SCATTERED SHOWERS AND TSTMS ARE OCCURRING E OF THE SURFACE TROUGH ACROSS THE FLORIDA PENINSULA EXTENDING INTO THE E GULF WITHIN 90 NM OF THE SURFACE TROUGH. THE REMAINDER OF THE GULF IS UNDER A SURFACE RIDGE WITH AXIS ALONG A NEW ORLEANS TO VERACRUZ MEXICO LINE AND ANCHORED BY A 1018 MB HIGH CENTERED NEAR 26N91W THAT IS RESULTING IN GENERALLY FAIR WEATHER W OF 90W...INCLUDING THE YUCATAN PENINSULA. CARIBBEAN SEA... A TROPICAL WAVE IS MOVING ACROSS THE WRN CARIBBEAN OVER ERN CUBA THROUGH CENTRAL JAMAICA TO NWRN COLOMBIA NEAR 8N76W. SCATTERED SHOWERS AND ISOLATED TSTMS ON DIFFLUENT FLOW ALOFT ARE OCCURRING FROM 14N-17N BETWEEN 75W-79W. THE UPPER LEVEL DIFFLUENCE IS FOCUSED ON AN UPPER LEVEL ANTICYCLONIC CIRCULATION CENTERED NEAR 11N75W IN THE SW CARIBBEAN AND IS GENERATING SCATTERED SHOWERS AND TSTMS S OF A LINE FROM 11N75W TO THE ERN COAST OF NICARAGUA NEAR 14N83W. THIS ACTIVITY EXTENDS ACROSS THE SRN PORTION OF CENTRAL AMERICA INTO THE E PACIFIC. THE AFOREMENTIONED UPPER LEVEL RIDGE EXTENDS TO THE WINDWARD ISLANDS ALONG 13N. ON THE NRN PERIPHERY OF THIS RIDGE...SCATTERED SHOWERS AND ISOLATED TSTMS ARE ACROSS HISPANIOLA...PUERTO RICO AND THE ERN CARIBBEAN E OF 71W. AS THE TROPICAL WAVE ALONG 58W IMPACTS THE LESSER ANTILLES...EXPECT INCREASED CLOUDINESS AND SCATTERED SHOWERS/ TSTMS THROUGH THE NEXT 24-36 HOURS. ATLANTIC OCEAN... A UPPER LEVEL TROUGH IS ACROSS THE SE CONUS AND EXTENDS UPPER LEVEL TROUGHING ACROSS THE FLORIDA PENINSULA EWD INTO THE SW NORTH ATLC. MOIST SWLY DIFFLUENT FLOW ALOFT IS GENERATING SCATTERED SHOWERS AND TSTMS ACROSS THE SRN FLORIDA PENINSULA. THIS UPPER LEVEL TROUGHING EXTENDS E TO AN UPPER LEVEL SHORTWAVE TROUGH CENTERED NEAR 26N75W. NUMEROUS SHOWERS AND SCATTERED TSTMS ARE FROM 20N-29N BETWEEN 65W-75W. THE REMAINDER OF THE CENTRAL AND ERN ATLC IS DOMINATED BY A BROAD SURFACE RIDGE ANCHORED BY A 1028 MB HIGH CENTERED NEAR 35N56W AND A 1027 MB HIGH CENTERED NEAR 34N41W THAT IS RESULTING IN GENERALLY FAIR WEATHER N OF 20N E OF 63W ACROSS THE SUBTROPICAL ATLC. $$ HUFFMAN