000 AXNT20 KNHC 240521 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 205 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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH WWW UTC. ...TROPICAL WAVES... AN EASTERN ATLANTIC OCEAN TROPICAL WAVE IS ALONG 21W S OF 19N MOVING W NEAR 10 KT. A 1010 MB LOW IS CENTERED ALONG THE WAVE AXIS NEAR 12N. LOW-LEVEL CYCLONIC FLOW AROUND THE WAVE AXIS AND CONCENTRATED AROUND THE LOW CENTER IS WELL DEFINED IN SATELLITE IMAGERY AS WELL AS A 2232 UTC ASCAT SCATTEROMETER PASS. 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 14N-17N BETWEEN 22W-27W...AND FROM 7N-12N BETWEEN 18W-22W. AN ATLANTIC OCEAN TROPICAL WAVE IS ALONG 48W/49W 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. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS FROM 19N-24N BETWEEN 45W-49W...AND FROM 7N-12N BETWEEN 46W-53W. THIS ACTIVITY IS ALSO ENHANCED BY DIFFLUENT FLOW ALOFT. ...THE ITCZ... THE ITCZ AXIS IS CENTERED ALONG 18N17W 11N23W 8N33W 11N47W 10N62W. SCATTERED MODERATE CONVECTION IS FROM 18N-19N BETWEEN 15W-17W. SIMILAR ACTIVITY IS WITHIN 150 NM S OF THE AXIS BETWEEN 24W-28W...AND BETWEEN 34W-41W. ...DISCUSSION... THE GULF OF MEXICO... AS OF 0300 UTC...A STATIONARY FRONT EXTENDS ACROSS THE NW GULF FROM 30N92W NEAR LAFAYETTE LOUISIANA ALONG 27N95W 25N96W CONTINUING AS A COLD FRONT TO 19N95W. SCATTERED SHOWERS/THUNDERSTORMS ARE BEHIND THE FRONT FROM 25N-28N BETWEEN 94W-97W...AND FROM 20N-23N BETWEEN 96W-98W. A FEW ISOLATED SHOWERS ARE WITHIN 150 NM AHEAD OF THE FRONT N OF 24N. NE SURFACE WINDS UP TO 20 KT ARE BEHIND THE FRONT. A SURFACE TROUGH IS ACROSS THE YUCATAN PENINSULA FROM 23N87W TO 17N90W SUPPORTING ISOLATED SHOWERS S OF 25N BETWEEN 86W-89W...AND SCATTERED SHOWERS/THUNDERSTORMS S OF 20N BETWEEN 90W-92W IN THE SE BAY OF CAMPECHE. ANOTHER SURFACE TROUGH EXTENDS ALONG THE W FLORIDA COAST FROM 31N83W TO 26N83W. SURFACE CONVERGENCE NEAR THE TROUGH IS SUPPORTING SCATTERED SHOWERS/THUNDERSTORMS WITHIN 100 NM W OF THE TROUGH AXIS BETWEEN 25N-28N...AND ALONG THE TROUGH AXIS N OF 28N. IN THE UPPER LEVELS...AN UPPER LEVEL RIDGE COVERS THE MAJORITY OF THE BASIN CENTERED NEAR 26N93W. A SHORTWAVE UPPER LEVEL E-W TROUGH EXTENDS INTO THE FAR SE GULF CONTRIBUTING TO THE SHOWERS OFF THE SW COAST OF FLORIDA. EXPECT THE FRONT TO REMAIN RELATIVELY STATIONARY OVER THE NEXT 24 HRS. THE CARIBBEAN SEA... SCATTERED SHOWERS/THUNDERSTORMS ARE OFF THE COASTS OF NICARAGUA AND HONDURAS FROM 13N-18N BETWEEN 80W-84W. THIS ACTIVITY IS ENHANCED BY A BROAD AREA OF DIFFLUENT FLOW ALOFT BETWEEN A SHORTWAVE UPPER LEVEL TROUGH ACROSS CUBA EMBEDDED IN A BROAD UPPER LEVEL TROUGH COVERING THE W ATLC EXTENDING INTO THE CARIBBEAN AND THE UPPER LEVEL RIDGE OVER THE GULF. THIS BROAD DIFFLUENT FLOW ALOFT AROUND THE BROAD UPPER TROUGH CENTERED NEAR 27N65W IS ALSO SUPPORTING SCATTERED SHOWERS/THUNDERSTORMS ACROSS HISPANIOLA AND PUERTO RICO N OF 18N BETWEEN 66W-73W. THE REMAINDER OF THE CARIBBEAN REMAINS FAIRLY CALM. FRESH TRADEWINDS ARE ACROSS MUCH OF THE BASIN BECOMING STRONG IN THE ERN CARIBBEAN. THE ATLANTIC OCEAN... A FEW ISOLATED SHOWERS ARE OFF THE SE COAST OF FLORIDA FROM 26N-29N W OF 74W ENHANCED BY WEAK DIFFLUENT FLOW BETWEEN THE UPPER RIDGE OVER THE GULF OF MEXICO AND AN UPPER LEVEL TROUGH COVERING THE W ATLC CENTERED NEAR 27N65W. THIS UPPER LEVEL TROUGH IS ALSO SUPPORTING SCATTERED SHOWERS/THUNDERSTORMS S OF 21N BETWEEN 66W-73W OVER PORTIONS OF PUERTO RICO AND HISPANIOLA. A SURFACE TROUGH EXTENDS FROM 32N63W TO 25N65W. SURFACE CONVERGENCE NEAR THE TROUGH AND SUPPORT FROM THE UPPER LOW NEAR 27N65W ARE GENERATING SCATTERED SHOWERS/THUNDERSTORMS FROM 28N-32N BETWEEN 52W-61W...AND ISOLATED SHOWERS FROM 25N-28N BETWEEN 53W-66W. ANOTHER SURFACE TROUGH EXTENDS FROM 23N52W TO 16N56W. NO SHOWERS ARE CURRENTLY ASSOCIATED WITH THE TROUGH. A BROAD SURFACE RIDGE COVERS THE REMAINDER OF THE ATLC. IN THE UPPER LEVELS...A BROAD UPPER RIDGE COVERS THE AREA E OF 53W E OF THE UPPER TROUGH CENTERED NEAR 27N65W. A LARGE AREA OF AFRICAN DUST IS E OF 40W. $$ WALTON