000 AXNT20 KNHC 241054 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 805 AM EDT THU SEP 24 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 1000 UTC. ...TROPICAL WAVES... AN EASTERN ATLANTIC OCEAN TROPICAL WAVE IS ALONG 23W S OF 17N MOVING W NEAR 15 KT. A 1009 MB LOW IS CENTERED ALONG THE WAVE AXIS NEAR 12N. HOWEVER...BASED ON THE FIRST VISIBLE SATELLITE IMAGES AND A 0754 UTC QUIKSCAT PASS...IT APPEARS THAT THE LOW CENTER IS LOCATED NEAR 12N27W WITH THE WAVE AXIS TILTS NE TO SW THROUGH THE LOW CENTER. THE WAVE WILL MOST LIKELY BE RELOCATED ON THE NEXT SURFACE ANALYSIS TO BETTER ALIGN WITH THIS NEW DATA. A LARGE AREA OF AFRICAN DUST SURROUNDS THE SYSTEM TO THE N AND WRAPPING AROUND THE W SIDE. DESPITE THE PRESENCE OF THE DUST...SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS FROM 12N-18N BETWEEN 20W-29W...AND FROM 7N-11N BETWEEN 19W-24W. AN ATLANTIC OCEAN TROPICAL WAVE IS ALONG 49W/50W S OF 20N MOVING W 15-20 KT. SATELLITE IMAGERY AND SATELLITE DERIVED WINDS INDICATE AN INVERTED-V LOW-LEVEL CLOUD PATTERN. THE WAVE ALSO COINCIDES WITH TWO DEEP LAYER MOISTURE MAXIMUMS...ONE NEAR THE NRN PORTION OF THE WAVE AND ANOTHER ALONG THE ITCZ. THIS MAY INDICATE THAT THE WAVE AXIS IS ABOUT TO FRACTURE. ISOLATED MODERATE/STRONG CONVECTION IS FROM 17N-26N BETWEEN 44W-49W...AND FROM 8N-14N BETWEEN 49W-54W. THIS ACTIVITY IS ALSO ENHANCED BY DIFFLUENT FLOW ALOFT. ...THE ITCZ... THE ITCZ AXIS IS CENTERED ALONG 17N16W 11N24W 6N35W 12N48W 10N62W. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS WITHIN 100 NM BOTH SIDES OF THE AXIS BETWEEN 34W-45W. ...DISCUSSION... THE GULF OF MEXICO... AS OF 0900 UTC...A STATIONARY FRONT EXTENDS ACROSS THE NW GULF FROM S CENTRAL LOUISIANA NEAR 30N92W ALONG 24N96W TO THE SW BAY OF CAMPECHE NEAR 18N94W. SCATTERED SHOWERS/THUNDERSTORMS ARE FROM 16N-21N W OF 93W. ISOLATED SHOWERS/POSSIBLE THUNDERSTORMS ARE WITHIN 200 NM AHEAD OF THE FRONT...AND WITHIN 75 NM BEHIND THE FRONT. N SURFACE WINDS UP TO 20 KT ARE BEHIND THE FRONT. A SURFACE TROUGH IS ACROSS THE YUCATAN PENINSULA FROM 23N89W TO 13N89W SUPPORTING ISOLATED SHOWERS ACROSS THE YUCATAN CHANNEL S OF 23N. ANOTHER SURFACE TROUGH EXTENDS OFF THE W FLORIDA COAST FROM 30N85W TO 24N85W. SURFACE CONVERGENCE NEAR THE TROUGH IS SUPPORTING SCATTERED SHOWERS/THUNDERSTORMS FROM 24N-25N BETWEEN 83W-86W...AND ISOLATED SHOWERS WITHIN 50 NM OF THE AXIS FROM 28N-30N. IN THE UPPER LEVELS...AN ELONGATED UPPER LEVEL RIDGE COVERS THE BASIN WITH AXIS FROM CENTRAL PENNSYLVANIA TO SRN ALABAMA CONTINUING ACROSS THE NW GULF TO CENTRAL MEXICO NEAR 23N101W. EXPECT THE TROUGH OVER THE YUCATAN PENINSULA TO MOVE WWD AND MERGE WITH THE REMNANT OF THE FRONT BY FRI. THE CARIBBEAN SEA... SCATTERED SHOWERS/THUNDERSTORMS ARE ACROSS THE WRN CARIBBEAN FROM 11N-21N BETWEEN 80W-85W. THIS ACTIVITY IS ENHANCED BY A BROAD AREA OF DIFFLUENT FLOW ALOFT BETWEEN THE UPPER RIDGE OVER THE GULF AND A BROAD UPPER LEVEL TROUGH COVERING THE W ATLC CENTERED NEAR 27N65W EXTENDING INTO THE CARIBBEAN. THE REMAINDER OF THE CARIBBEAN REMAINS FAIRLY CALM THIS MORNING. FRESH TRADEWINDS ARE ACROSS MUCH OF THE BASIN BECOMING STRONG IN THE ERN CARIBBEAN. THE ATLANTIC OCEAN... AS OF 0900 UTC...A SURFACE TROUGH EXTENDS OFF THE E COAST OF FLORIDA FROM 31N77W TO 28N77W. SURFACE CONVERGENCE NEAR THE TROUGH IS SUPPORTING SCATTERED SHOWERS/THUNDERSTORMS FROM 27N-29N BETWEEN 75W-77W. A FEW ISOLATED SHOWERS ARE OFF THE SE COAST OF FLORIDA S OF 28N W OF 77W ENHANCED BY WEAK DIFFLUENT FLOW BETWEEN THE UPPER RIDGE OVER THE GULF OF MEXICO AND THE UPPER LEVEL TROUGH COVERING THE W ATLC CENTERED NEAR 27N65W. THIS UPPER LEVEL TROUGH IS SUPPORTING A SURFACE TROUGH FROM 32N63W TO 24N65W...AND A SECOND SURFACE TROUGH FROM 32N53W TO 30N56W. SURFACE CONVERGENCE NEAR THESE TROUGHS IS SUPPORTING SCATTERED SHOWERS/THUNDERSTORMS N OF 26N BETWEEN 53W-62W...AND ISOLATED SHOWERS FROM 26N-32N BETWEEN 62W-68W. A THIRD SURFACE TROUGH EXTENDS FROM 19N54W TO 23N52W SUPPORTING ISOLATED SHOWERS FROM 23N-25N BETWEEN 49W-54W. A BROAD SURFACE RIDGE COVERS THE REMAINDER OF THE ATLC. IN THE UPPER LEVELS...A BROAD UPPER RIDGE COVERS THE AREA E OF 55W E OF THE UPPER TROUGH CENTERED NEAR 27N65W. A LARGE AREA OF AFRICAN DUST IS E OF 40W. $$ WALTON