000 AXNT20 KNHC 050002 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 805 PM EDT FRI SEP 04 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 2315 UTC. ...SPECIAL FEATURES... TROPICAL WAVE IS JUST W OF THE CAPE VERDE ISLANDS ALONG 26W S OF 20N MOVING W AT 20 KT. A 1012 MB LOW IS EMBEDDED ON THE WAVE AXIS NEAR 14N26W. SATELLITE IMAGERY SHOWS A LARGE CLOUD MASS FROM 9N-21N BETWEEN 23W-31W. THE WAVE IS ALSO WITHIN A DEEP LAYER MOISTURE MAXIMUM AS INDICATED BY THE SSMI TOTAL PRECIPITABLE WATER IMAGERY. SCATTERED MODERATE CONVECTION IS FROM 15N-18N BETWEEN 25W-28W...AND FROM 9N-12N BETWEEN 27W-30W. SOME ADDITIONAL DEVELOPMENT OF THIS SYSTEM IS POSSIBLE OVER THE NEXT COUPLE OF DAYS. ...TROPICAL WAVES... TROPICAL WAVE IS ALONG 37W S OF 19N MOVING W AT 12 KT. A 1013 MB LOW IS EMBEDDED ON THE WAVE AXIS NEAR 15N37W. THE WAVE COINCIDES WITH A DEEP LAYER MOISTURE MAXIMUM OBSERVED IN THE SSMI TOTAL PRECIPITABLE WATER IMAGERY. SATELLITE IMAGERY SHOWS SAHARAN DUST TO THE W OF THE WAVE AXIS AND ALSO TO THE NE OF SURFACE LOW. THIS SAHARAN AIR LAYER IS INHIBITING ANY SIGNIFICANT DEEP CONVECTION WITH ONLY A SMALL AREA OF ISOLATED MODERATE CONVECTION FROM 15N-17N BETWEEN 36W-38W. TROPICAL WAVE IS ALONG 55W S OF 16N MOVING W AT 12 KT. THE WAVE REMAINS RELATIVELY LOW-AMPLITUDE WITH A WEAKENING 850 MB VORTICITY SIGNATURE IN THE CIMSS WAVETRAK MODEL GUIDANCE. SAHARAN DUST REMAINS TO THE E OF THE WAVE AXIS LIMITING CONVECTION. ...ITCZ... THE ITCZ AXIS IS CENTERED ALONG 11N15W 14N20W 10N30W 8N40W 89W61W. BESIDES THE CONVECTION MENTIONED IN THE SPECIAL FEATURE SECTION ABOVE...ISOLATED MODERATE CONVECTION IS 7N-10N BETWEEN 30W-36W. ...DISCUSSION... GULF OF MEXICO... A SURFACE TROUGH EXTENDS FROM CENTRAL FLORIDA NEAR 29N80W TO THE W GULF NEAR 25N95W. SCATTERED MODERATE CONVECTION IS INLAND OVER CENTRAL AND SOUTHERN FLORIDA. SCATTERED SHOWERS ARE WITHIN 60 NM OF THE REMAINDER OF THE TROUGH. ELSEWHERE...ISOLATED MODERATE CONVECTION IS OVER THE SW GULF...W CUBA...AND THE YUCATAN PENINSULA. THE REMAINDER OF THE GULF HAS SCATTERED HIGH CLOUDS SKIES WITH LIGHT WINDS. IN THE UPPER LEVELS...AN UPPER LEVEL LOW IS CENTERED OVER THE E GULF NEAR 24N86W. AN UPPER LEVEL RIDGE IS OVER THE W GULF W OF 90W. EXPECT...A SURFACE TROUGH TO BE OVER THE TEXAS COAST WITHIN 24 HOURS WITH SHOWERS. ALSO EXPECT CONVECTION TO PERSIST OVER THE SAME AREAS MENTIONED ABOVE FOR THE NEXT 24 HOURS. CARIBBEAN SEA... THE REMNANTS OF ERIKA IS NOW A SURFACE TROUGH IN THE VICINITY OF PUERTO RICO PRODUCING SHOWERS. SCATTERED MODERATE CONVECTION IS ALSO OVER THE LEEWARD ISLANDS FROM 16N-18N BETWEEN 63W-65W. ELSEWHERE...A LARGE AREA OF SCATTERED MODERATE TO ISOLATED STRONG CONVECTION IS OVER THE SW CARIBBEAN S OF 16N BETWEEN 78W-85W. SIMILAR CONVECTION IS MOSTLY INLAND OVER N COLOMBIA AND NW VENEZUELA FROM 7N-12N BETWEEN 70W-75W. EXPECT...MORE CONVECTION OVER THE LESSER ANTILLES...THE SW CARIBBEAN...AND CENTRAL AMERICA OVER THE NEXT 24 HOURS. ATLANTIC OCEAN... A SURFACE TROUGH ENTERS THE DISCUSSION AREA NEAR 32N77W AND EXTENDS SW TO CENTRAL FLORIDA NEAR COCOA BEACH. SCATTERED SHOWERS ARE OVER THE N BAHAMAS AND THE W ATLANTIC FROM 24N-32N BETWEEN 77W-80W. ANOTHER SURFACE TROUGH IS OVER THE CENTRAL ATLANTIC ALONG 29N60W 23N58W. SCATTERED SHOWERS ARE WITHIN 90 NM OF THE TROUGH AXIS. A 1023 MB HIGH IS ALSO OVER THE CENTRAL ATLANTIC NEAR 32N51W. IN THE UPPER LEVELS...AN UPPER LEVEL LOW IS OVER THE CENTRAL ATLANTIC NEAR 25N61W. ANOTHER UPPER LEVEL LOW IS OVER THE E ATLANTIC NEAR 28N39W. FURTHER S...AN UPPER LEVEL HIGH IS OVER THE TROPICS NEAR 17N56W. ANOTHER UPPER LEVEL HIGH IS OVER W AFRICA NEAR 20N14W. EXPECT THE SPECIAL FEATURE TROPICAL WAVE TO BE THE DOMINATE WEATHER PRODUCER IN THE ATLANTIC OVER THE NEXT 24 HOURS. $$ FORMOSA