000 AXNT20 KNHC 030552 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 205 AM EDT SUN 03 OCT 2004 TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL AMERICA...GULF OF MEXICO...CARIBBEAN SEA...NORTHEASTERN SECTIONS OF SOUTH AMERICA...AND ATLC OCEAN TO THE AFRICAN COAST FROM THE EQUATOR TO 32N. THE FOLLOWING INFORMATION IS BASED ON SATELLITE IMAGERY...WEATHER OBSERVATIONS... RADAR...AND METEOROLOGICAL ANALYSIS. BASED ON 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 0315 UTC. ...SPECIAL FEATURES... TROPICAL STORM LISA IS CENTERED NEAR 43.9N 31.6W AT 03/0300 UTC. LISA IS MOVING ENE AT 23 KT. MAXIMUM SUSTAINED WIND SPEED IS 50 KT WITH GUSTS TO 60 KT AND THE ESTIMATED MINIMUM CENTRAL PRESSURE IS 992 MB. THIS IS THE LAST ADVISORY WRITTEN BY THE NATIONAL HURRICANE CENTER. LISA HAS BECOME EXTRATROPICAL WITH NO ASSOCIATED DEEP CONVECTION OR SHOWER ACTIVITY. ...TROPICAL WAVES... EASTERN MOST TROPICAL WAVE IS ALONG 40W/41W S OF 17N MOVING W 10-15 KT. WAVE IS UNDER AN UPPER RIDGE WHICH IS DISPLACING THE CONVECTION TO THE E DUE TO THE WESTERLY SHEAR. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS FROM 15N-18N BETWEEN 33W-37W. TROPICAL WAVE ABOUT 580 NM E OF BARBADOS IS ALONG 49W/50W S OF 19N MOVING W 10-15 KT. WELL-DEFINED LOW LEVEL CIRCULATION IS EVIDENT IN SATELLITE IMAGERY NEAR 11N. HOWEVER...NO SIGNS OF FURTHER DEVELOPMENT. CLUSTERS OF SCATTERED MODERATE/ISOLATED STRONG CONVECTION ARE FROM 10N-14N BETWEEN 44W-50W. TROPICAL WAVE OVER THE E CARIBBEAN IS ALONG 65W/66W S OF 20N MOVING W 10-15 KT. SIGNATURE INVERTED V CURVATURE IS OBSERVED ON INFRARED SATELLITE IMAGERY. SHOWER ACTIVITY IS UNDER WESTERLY SHEAR AT THE BASE OF AN UPPER TROUGH. AREA OF SCATTERED SHOWERS/ISOLATED THUNDERSTORMS ARE FROM 14N-18N BETWEEN 64W-71W. TROPICAL WAVE OVER THE W CARIBBEAN IS ALONG 88W S OF 20N MOVING W 10-15 KT. WAVE HAS BEEN INTERACTING WITH A STRONG MID/UPPER LEVEL LOW WHICH IS NOW MOVING INLAND OVER CENTRAL AMERICA THEN INTO THE E PACIFIC REGION. MOST OF THE ASSOCIATED DEEP CONVECTION IS INLAND OVER CENTRAL AMERICA INTO THE E PACIFIC. ...ITCZ... ITCZ IS CENTERED ALONG 12N10W 6N26W 10N38W 11N48W 8N59W 9N63W. SCATTERED MODERATE/STRONG CONVECTION IS MOVING OFF THE COAST OF AFRICA WITHIN 60 NM FROM 8N-12N. CLUSTERS OF SCATTERED MODERATE/ ISOLATED STRONG CONVECTION ARE FROM 2N-11N BETWEEN 20W-36W...AND FROM 8N-14N BETWEEN 36W-44W. ...DISCUSSION... GULF OF MEXICO... LARGE MID/UPPER LEVEL RIDGE DOMINATES THE ENTIRE GULF WITH AXIS EXTENDING FROM CENTRAL MEXICO NEAR MEXICO CITY NE ACROSS CENTRAL FLORIDA OVER W ATLC TO BEYOND 32N75W. BROAD DEEP LAYERED TROUGH COVERS MOST OF THE UNITED STATES. THIS SET-UP IS DRAWING THE TROPICAL MOISTURE UP AND OVER THE RIDGE LEAVING THE MOST OF THE GULF UNDER STRONG SUBSIDENCE AND TRANQUIL WEATHER. THE ONLY EXCEPTIONS ARE ALONG THE IMMEDIATE TEXAS AND LOUISIANA COASTS WHERE ISOLATED SHOWERS AND POSSIBLE THUNDERSTORMS ARE WITHIN 120 NM OF THE COAST. AN AREA OF LOW LEVEL SCATTERED SHOWERS/ISOLATED THUNDERSTORMS ARE ACROSS THE S GULF WITHIN 75/100 NM OF LINE FROM 26N79W ACROSS S FLORIDA TO OFF THE COAST OF MEXICO NEAR 22N96W. DIVERGENT FLOW OVER OVER THE BAY OF CAMPECHE AHEAD OF THE TROPICAL WAVE IS PRODUCING SCATTERED MODERATE/ISOLATED STRONG CONVECTION S OF 20N FROM 91W-94W. THE RIDGE IS EXPECTED TO REMAIN IN PLACE FOR NEXT 24 HOURS AS THE MID/UPPER LOW OVER CENTRAL AMERICA CONTINUES TO MOVE WEST INTO THE E PACIFIC CROSSING THE BAY OF CAMPECHE DURING TODAY INTO TONIGHT. AT THE SURFACE...A COLD FRONT ENTERS THE GULF OVER LOUISIANA NEAR 30N91W TO 29N94W WHERE IT CONTINUES AS A STATIONARY FRONT INLAND OVER TEXAS TO BEYOND 28N99W. A PRE-FRONTAL TROUGH EXTENDS FROM THE FLORIDA PANHANDLE NEAR 31N83W SW TO THE CENTRAL GULF NEAR 27N90W. CARIBBEAN SEA... STRONG MID/UPPER LEVEL LOW THAT HAS PLAGUED THE W CARIBBEAN OVER THE PAST FEW DAYS IS MOVING INLAND OVER HONDURAS NEAR 15N85W AND THE TROPICAL WAVE IS MOVING INLAND OVER THE YUCATAN PENINSULA. BOTH THE UPPER LOW AND TROPICAL WAVE ARE MOVING WESTWARD AND THE ASSOCIATED SHOWER ACTIVITY/CONVECTION WILL CONTINUE ACROSS CENTRAL AMERICA TODAY. A MID/UPPER RIDGE AXIS IS SETTING UP ACROSS THE W CARIBBEAN FROM COLOMBIA NEAR 10N76W NW TO THE YUCATAN CHANNEL NEAR E CUBA. THIS SCENARIO IS PRODUCING CLUSTERS OF SCATTERED MODERATE/ISOLATED STRONG CONVECTION DOTTING THE AREA W OF 77W. OVER THE E CARIBBEAN A LARGE MID/UPPER LEVEL TROUGH FROM THE CENTRAL ATLC EXTENDS S TO THE COAST OF SOUTH AMERICA NEAR VENEZUELA. CONFLUENT FLOW OF THIS TROUGH AND THE TROPICAL WAVE BENEATH IS PRODUCING SCATTERED SHOWERS/ISOLATED THUNDERSTORMS OVER THE NE CARIBBEAN. THE MID/UPPER LOW CURRENTLY OVER HONDURAS IS EXPECTED TO CONTINUE TO MOVE WEST ALLOWING THE MID/UPPER LEVEL RIDGE TO CONTINUE TO BUILD ACROSS THE W CARIBBEAN. MEANWHILE THE UPPER TROUGH OVER THE E CARIBBEAN IS EXPECTED TO REMAIN NEARLY STATIONARY ALTHOUGH RELAXING A BIT IN 24 HOURS. SUBTROPICAL ATLANTIC... LARGE MID/UPPER LEVEL RIDGE PREVAILS OVER THE W ATLC EXTENDING FROM CENTRAL FLORIDA NE BEYOND 32N57W. THE RIDGE IS PARTIALLY DISRUPTED BY A WEAK UPPER LEVEL SHORTWAVE TROUGH EXTENDING FROM BERMUDA S TO 26N71W. HOWEVER...THIS FEATURE IS NOT PRODUCING ANY SIGNIFICANT WEATHER. OVER THE CENTRAL ATLC...A LARGE MID/UPPER LEVEL LOW IS CENTERED NEAR 27N56W CONTINUES TO PRODUCE CLOUDINESS AND SCATTERED SHOWERS/THUNDERSTORMS FROM 18N-33N BETWEEN 51W-60W. THE TROUGH FROM THE LOW EXTENDS S OVER THE E CARIBBEAN AND W TROPICAL ATLC N OF 10N 56W-70W. OVER THE E ATLC...A WELL DEFINED MID/UPPER LEVEL HIGH IS SITUATED JUST N OF THE REGION NEAR 33N38W WITH ANTICYCLONIC FLOW EXTENDING S TO 24N FROM 30W-50W. ELSEWHERE...A SERIES OF MID TO UPPER LEVEL LOWS AND TROUGH AXIS EXTENDS FROM AN UPPER LOW OVER AFRICA JUST SE OF GIBRALTAR THROUGH 32N8W TO A SECOND LOW NEAR 29N24W TO A THIRD LOW NEAR 23N35W. AT THE SURFACE... SUBTROPICAL RIDGE IS PRIMARILY CONFINED N OF THE REGION WITH GENERALLY LIGHT TO MODERATE TRADES. A SURFACE TROUGH SPLITS THE RIDGE IN THE CENTRAL/WESTERN ATLANTIC EXTENDING FROM 32N59W S ALONG 28N63W TO 23N66W. TROPICAL ATLANTIC... WELL DEFINED MID/UPPER LEVEL HIGH IS CENTERED OFF THE COAST OF AFRICA NEAR 10N23W WITH ANTICYCLONIC FLOW COVERING THE AREA S OF 23N E OF 35W. AN UPPER LEVEL LOW IS SITUATED OFF THE COAST OF SOUTH AMERICA NEAR 9N54W WITH WEAK CYCLONIC FLOW S OF 12N W OF 40. $$ WALLACE