000 AXNT20 KNHC 070551 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 205 AM EDT TUE OCT 07 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 STORM MARCO IS CENTERED NEAR 19.9N 95.7W AT 07/0600 UTC OR ABOUT 115 NM ESE OF TUXPAN MEXICO MOVING WNW AT 6 KT. ESTIMATED MINIMUM CENTRAL PRESSURE IS 998 MB. MAXIMUM SUSTAINED WIND SPEED IS 55 KT WITH GUSTS TO 65 KT. SEE THE LATEST NHC FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMAT3/ WTNT23 KNHC FOR MORE DETAILS. MARCO IS A RELATIVELY SMALL TROPICAL STORM WITH TROPICAL STORM FORCE WINDS EXTENDING OUTWARD UP TO ABOUT 30 NM FROM THE CENTER. SCATTERED MODERATE CONVECTION IS WITHIN 30 NM OF THE CENTER IN THE W BAY OF CAMPECHE. ...TROPICAL WAVES... TROPICAL WAVE WAS INTRODUCED OFF THE COAST OF AFRICA ALONG 19W/20W S OF 11N MOVING W BASED ON A QUIKSCAT PASS BUT DOES NOT PRESENT THE CLASSIC INVERTED-V CURVATURE. SMALL CLUSTERS OF SCATTERED MODERATE/ISOLATED STRONG CONVECTION ARE FROM 3N-8N BETWEEN 17W-20W. TROPICAL WAVE IS ALONG 36W S OF 15N MOVING W NEAR 10 KT. A SMALL MID-LEVEL CIRCULATION IS OBSERVED ON SATELLITE IMAGERY CENTERED ALONG THE WAVE NEAR 11N. CLUSTERS OF SCATTERED MODERATE CONVECTION ARE FROM 10N-14N BETWEEN 35W-38W. TROPICAL WAVE IS ALONG 63W S OF 19N MOVING W NEAR 10 KT. WEAK INVERTED-V CURVATURE IN THE LOW LEVEL CLOUD FIELD. WAVE IS MOVING BENEATH STRONG NW WINDS ALOFT...AND THEREFORE NO SHOWERS OR DEEP CONVECTION ARE ASSOCIATED WITH THE WAVE. TROPICAL WAVE IS ALONG 73W S OF 19N MOVING W NEAR 10 KT. WAVE IS MOVING BENEATH AN AREA OF UPPER DIFFLUENCE WITH HIGH CLOUDS OBSCURING ANY SIGNATURE AT LOWER LEVELS THEREFORE POSITION IS BASED ON EXTRAPOLATION. ANY ACTIVITY NEAR THIS WAVE IS DUE TO UPPER LEVEL FEATURES. ...THE ITCZ... THE ITCZ AXIS IS ANALYZED ALONG 11N14W 5N24W 10N35W 9N41W 10N62W ACROSS THE N PORTION OF SOUTH AMERICA AND THE SW CARIBBEAN ENTERING THE E PACIFIC ACROSS COSTA RICA. SCATTERED/NUMEROUS STRONG CONVECTION IS MOVING OFF W AFRICA FROM 10N-14N E OF 18W. SCATTERED MODERATE/STRONG CONVECTION IS FROM 6N-10N BETWEEN 20W-25W WITH SMALL CLUSTERS OF SIMILAR CONVECTION FROM 6N-12N BETWEEN 46W-55W. CLUSTERS OF SCATTERED MODERATE/ISOLATED STRONG CONVECTION ARE WITHIN 150 NM ALONG THE COAST OF SW AFRICA S OF 7N W OF 9W AND WITHIN 60 NM OF LINE FROM 12N47W TO 16N50W. ...DISCUSSION... GULF OF MEXICO... TROPICAL STORM MARCO IS LOCATED IN THE BAY OF CAMPECHE...SEE SPECIAL FEATURES ABOVE FOR MORE DETAILS. A BROAD UPPER RIDGE COVERS THE GULF ANCHORED ALONG THE N COAST OF THE YUCATAN PENINSULA BRINGING MOIST TROPICAL AIR ACROSS MOST OF THE GULF EXCEPT ALONG THE TEXAS AND LOUISIANA COAST. DIFFLUENCE ALOFT IS GENERATING CLUSTERS OF SCATTERED SHOWERS/ISOLATED THUNDERSTORMS OVER THE NE GULF N OF 25N E OF 89W ACROSS PORTIONS OF THE SE US. THE NEXT FRONTAL BOUNDARY EXPECTED TO ENTER THE GULF LATE TUE. CARIBBEAN SEA... BROAD UPPER RIDGE IN THE GULF OF MEXICO CLIPS THE FAR NW CARIBBEAN AS THE UPPER LOW THAT HAS BEEN TRACKING W COVERS THE REMAINDER OF THE W CARIBBEAN CENTERED OFF THE COAST OF NICARAGUA/HONDURAS NEAR 15N83W GENERATING ISOLATED SHOWERS S OF 18N W OF 78W TO INLAND OVER CENTRAL AMERICA. THE REMAINDER OF THE CARIBBEAN IS DOMINATED BY A BROAD UPPER RIDGE ANCHORED OVER NW VENEZUELA E OF 75W TO OVER THE LESSER ANTILLES. DIFFLUENCE ALOFT GENERATING DENSE CLOUD COVER WITH ISOLATED SHOWERS BETWEEN THE TROPICAL WAVES. ATLANTIC OCEAN... A LINGERING DISSIPATING SURFACE TROUGH REMAINS ACROSS THE W ATLC EXTENDING ACROSS BERMUDA ALONG 29N73W TO NEAR VERO BEACH FLORIDA. A WEAKENING UPPER RIDGE EXTENDING FROM THE GULF OF MEXICO DOMINATES THE W ATLC W OF 75W GENERATING SCATTERED SHOWERS/ISOLATED THUNDERSTORMS FROM 26N-30N W OF 77W ACROSS THE FLORIDA PENINSULA. A LARGE CUT-OFF UPPER LOW IS IN THE W/CENTRAL ATLC CENTERED NEAR 23N62W WITH A SURFACE TROUGH EXTENDING FROM 27N59W TO 21N62W PRODUCING SCATTERED MODERATE/ISOLATED STRONG CONVECTION FROM 23N-26N BETWEEN 56W-59W AND SCATTERED SHOWERS/ ISOLATED THUNDERSTORMS ACROSS THE REMAINDER OF THE AREA FROM 21N-30N BETWEEN 55W-62W. AN UPPER TROUGH CONTINUES TO DIG SW OVER THE E/CENTRAL ATLC INTO THE TROPICAL ATLC ACROSS THE CANARY ISLANDS SW TO A SMALL UPPER LOW NEAR 22N31W TO 15N42W WITH AN UPPER RIDGE DEVELOPING TO THE N NEAR 30N36W EXTENDING NE TO THE AZORES...THUS PRODUCING DIFFLUENCE ALOFT TO GENERATE SCATTERED SHOWERS W OF THE CAPE VERDE ISLANDS FROM 13N-27N BETWEEN 24W-31W. A SURFACE RIDGE IS BUILDING ACROSS THE E ATLC N OF 20N E OF 50W ANCHORED BY A 1026 MB HIGH W OF MADEIRA ISLANDS NEAR 32N20W. $$ WALLACE