000 AXNT20 KNHC 080547 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 205 AM EDT WED OCT 08 2008 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 0315 UTC. ...SPECIAL FEATURES... TROPICAL DEPRESSION MARCO IS CENTERED NEAR 20.0N 97.5W AT 08/0300 UTC OR ABOUT 60 NM S OF TUXPAN MEXICO MOVING W AT 4 KT. ESTIMATED MINIMUM CENTRAL PRESSURE IS 1008 MB. MAXIMUM SUSTAINED WIND SPEED IS 20 KT WITH GUSTS TO 30 KT. THIS WAS THE LAST NHC FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMAT3/WTNT23 KNHC FOR MORE DETAILS. MARCO HAS RAPIDLY DISSIPATING AND IS POORLY ORGANIZED. SCATTERED SHOWERS/ISOLATED THUNDERSTORMS ARE IN THE GULF WATERS S OF 22N W OF 95W TO INLAND OVER MEXICO. ...TROPICAL WAVES... TROPICAL WAVE IS ALONG 24W S OF 13N MOVING W 10-15 KT. BROAD MID-LEVEL CYCLONIC CURVATURE IS OBSERVED ON SATELLITE IMAGERY. NO ASSOCIATED DEEP CONVECTION. TROPICAL WAVE IS ALONG 36W/37W S OF 16N WITH A WEAK 1011 MB LOW ALONG THE WAVE NEAR 12N MOVING W 5-10 KT. SMALL LOW LEVEL SWIRL IS ASSOCIATED WITH THE LOW WITH CLUSTERS SCATTERED MODERATE/ISOLATED STRONG CONVECTION FROM 11N-13N BETWEEN 34W-38W. TROPICAL WAVE IS ALONG 52W S OF 16N MOVING W 10-15 KT. BROAD MID LEVEL INVERTED-V CURVATURE IS OBSERVED ON SATELLITE IMAGERY. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS FROM 12N-15N BETWEEN 52W-54W. TROPICAL WAVE IS ALONG 70W/71W S OF 18N MOVING W NEAR 15 KT. WAVE IS BENEATH AN UPPER RIDGE WITH UPPER DIFFLUENCE GENERATING HIGH CLOUDS AND SHOWER ACTIVITY OVER THE AREA...THUS MASKING ANY SATELLITE SIGNATURE. TROPICAL WAVE IS ALONG 80W S OF 20N MOVING W NEAR 15 KT. THE WAVE IS BENEATH MODERATE SUBSIDENCE/DRY AIR BETWEEN AN UPPER HIGH AND UPPER LOW THAT DOMINATES THE CARIBBEAN...THUS NO ASSOCIATED SHOWERS/CONVECTION. ...THE ITCZ... THE ITCZ AXIS IS ANALYZED ALONG 14N16W 7N26W 11N37W 9N50W 8N61W. A SMALL 1011 MB LOW IS JUST N OF THE ITCZ CENTERED NEAR 14N32W GENERATING SCATTERED MODERATE/STRONG CONVECTION WITHIN 60 NM OF LINE FROM 16N31W TO 14N32W. SCATTERED MODERATE/STRONG CONVECTION IS WITHIN 200 NM ALONG THE W COAST OF AFRICA FROM 7N-13N. SMALL CLUSTERS OF SCATTERED MODERATE CONVECTION ARE FROM 3N-13N BETWEEN 18W-43W. ...DISCUSSION... GULF OF MEXICO... TROPICAL DEPRESSION MARCO IS NOW INLAND OVER MEXICO...SEE SPECIAL FEATURES ABOVE FOR MORE DETAILS. A DEEP LAYERED TROUGH IS MOVING OVER THE MISSISSIPPI VALLEY INTO THE FAR NW GULF WITH THE ASSOCIATED COLD FRONT ALONG THE COAST OF TEXAS OVER S TEXAS NEAR CORPUS CHRISTI. A WEAK PRE-FRONTAL TROUGH ENTERS THE GULF OVER W LOUISIANA NEAR 30N93W EXTENDING S TO JUST OFF THE COAST NEAR BROWNSVILLE TEXAS. MOIST TROPICAL AIR IS TO THE SE OF THE FRONT WITH STRONG SUBSIDENCE AND DRY STABLE AIR NW OF THE FRONT. A BROAD UPPER RIDGE COVERS THE REMAINING GULF WATERS ANCHORED ALONG THE COAST OF MEXICO NEAR 20N96W. UPPER DIFFLUENCE E OF THE FRONT IS GENERATING CLUSTERS OF SCATTERED SHOWERS/ISOLATED THUNDERSTORMS OVER MOST OF THE GULF WITHIN 140 NM THE GULF COAST STATES NEAR 30N86W TO OVER MEXICO NEAR 24N98W. MODERATE/STRONG EASTERLY WINDS ARE OVER THE E GULF USHERING IN ISOLATED SHOWERS THROUGH THE FLORIDA STRAITS AND ACROSS S FLORIDA S OF 26N E OF 85W. CARIBBEAN SEA... AN UPPER LOW COVERS THE W CARIBBEAN CENTERED ALONG THE COAST OF HONDURAS NEAR 16N86W GENERATING SCATTERED SHOWERS/ISOLATED THUNDERSTORMS FROM 15N-22N BETWEEN 82W AND THE YUCATAN COAST. AN UPPER TROUGH COVERING THE W ATLC DIPS S JUST OVER THE N CARIBBEAN ISLANDS FROM THE VIRGIN ISLANDS TO HISPANIOLA WHILE THE REMAINDER OF THE CARIBBEAN IS DOMINATED BY A BROAD UPPER RIDGE ANCHORED OVER VENEZUELA E OF 80W TO ACROSS THE LESSER ANTILLES. DIFFLUENCE ALOFT IS GENERATING DENSE CLOUD CLOVER WITH SCATTERED SHOWERS/ISOLATED THUNDERSTORMS OVER THE AREA MAINLY S OF 17N E OF 76W TO ACROSS THE LESSER ANTILLES. ATLANTIC OCEAN... BROAD DEEP LAYERED TROUGH COVERS THE W ATLC TO THE N CARIBBEAN ISLANDS W OF 55W WITH AN EMBEDDED UPPER LOW NEAR 23N60W. THE ASSOCIATED COLD FRONT ENTERS THE REGION NEAR 32N55W EXTENDING WSW ALONG 28N65 TO JUST OFFSHORE OF THE FLORIDA COAST NEAR PALM BEACH. ISOLATED SHOWERS ARE WITHIN 60 NM S OF THE FRONT. A PRE-FRONTAL TROUGH EXTENDS FROM 30N58W TO 23N63W WITH SCATTERED SHOWERS/ISOLATED THUNDERSTORMS WITHIN 180 NM E OF THE TROUGH AND E OF THE FRONT N OF 30N. AN UPPER RIDGE IS IN THE NE ATLC ANCHORED NEAR 31N35W AND EXTENDS NE TO OVER THE AZORES. AN UPPER LOW IS ACROSS THE CENTRAL TROPICAL ATLC CENTERED NEAR 20N36W WITH A SURFACE TROUGH EXTENDING FROM 26N24W TO 29N37W. BETWEEN THE DEEP LAYERED TROUGH OVER THE W ATLC AND THIS UPPER LOW IS UPPER LEVEL DIFFLUENCE TO GENERATE AN AREA OF SCATTERED SHOWERS/THUNDERSTORMS FROM 19N-26N BETWEEN 52W-59W. AN UPPER RIDGE AGAIN EXTENDS FROM AFRICA ACROSS THE E TROPICAL ATLC ALONG 15N S OF 23N TO 30W. A SURFACE RIDGE REMAINS OVER THE E ATLC N OF 20N E OF 50W WITH A WEAKNESS IN THE IMMEDIATE VICINITY OF THE SURFACE TROUGH. $$ WALLACE