000 AXNT20 KNHC 262342 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 805 PM EDT MON OCT 26 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 2315 UTC. ...TROPICAL WAVES... TROPICAL WAVE IS ALONG 24W S OF 16N MOVING W NEAR 10 KT. LOW-LEVEL CYCLONIC TURNING IS EVIDENT ON SATELLITE IMAGERY NEAR THE WAVE AXIS. THE WAVE ALSO COINCIDES WITH A DEEP LAYER MOISTURE MAXIMUM AS OBSERVED IN TOTAL PRECIPITABLE WATER IMAGERY. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS FROM 8N-16N BETWEEN 19W-27W. TROPICAL WAVE IS ALONG 55W S OF 17N MOVING W NEAR 15 KT. THE WAVE LIES WITHIN A BROAD AREA OF DEEP LAYER MOISTURE BETWEEN 49W-59W AS OBSERVED IN TOTAL PRECIPITABLE WATER IMAGERY. NO DEEP CONVECTION IS CURRENTLY ASSOCIATED WITH THE WAVE...HOWEVER... ISOLATED SHOWERS ARE FROM 11N-17N BETWEEN 51W-57W AND ARE BEING ENHANCED BY UPPER LEVEL DIFFLUENCE E OF AN UPPER LEVEL LOW CENTERED OVER THE LEEWARD ISLANDS NEAR 17N60W. ...ITCZ... THE ITCZ AXIS IS CENTERED ALONG 11N15W 12N22W 11N25W 8N36W 11N53W 11N57W 10N63W. SCATTERED MODERATE TO STRONG CONVECTION IS ALONG THE W AFRICA COAST FROM 7N-13N BETWEEN 9W-16W. CLUSTERS OF SCATTERED SHOWERS AND ISOLATED MODERATE CONVECTION ARE FROM 1N-12N BETWEEN 38W-48W. ...DISCUSSION... GULF OF MEXICO... AS OF 2100 UTC...A COLD FRONT EXTENDS INTO THE NW GULF NEAR SW LOUISIANA ALONG 30N93W TO BROWNSVILLE TEXAS NEAR 26N97W AND INTO INTERIOR NE MEXICO. LOW-LEVEL CONVERGENCE AND ATMOSPHERIC INSTABILITY ARE FUELING NUMEROUS SHOWERS AND SCATTERED TSTMS ALONG THE FRONT AND WITHIN 90/120 NM BEHIND THE FRONT...WITH SCATTERED PRE-FRONTAL SHOWERS AND ISOLATED TSTMS ACROSS MUCH OF THE CENTRAL GULF FROM 21N TO THE U.S. GULF COAST W OF 87W TO THE FRONTAL BOUNDARY. THE COLD FRONT IS SUPPORTED ALOFT BY AN UPPER LEVEL TROUGH THAT IS PROGRESSING ACROSS WEST TEXAS AND NORTHERN MEXICO CURRENTLY AND CONTINUES TO PROVIDE AMPLE UPPER LEVEL DIFFLUENCE ACROSS THE GULF THIS EVENING. AHEAD OF THE FRONT... MOSTLY E-SE SURFACE WINDS UP TO 15 KT ARE OBSERVED WITH A SURFACE TROUGH EXTENDING FROM THE YUCATAN PENINSULA TO 27N86W. A FEW ISOLATED SHOWERS ARE WITHIN 120 NM OF THE SURFACE TROUGH. CARIBBEAN SEA... AN UPPER LEVEL RIDGE IS CENTERED OVER GUATEMALA NEAR 17N91W AND CONTINUES TO PROVIDE DRY AIR AND SUBSIDENCE ALOFT OVER THE NW CARIBBEAN W OF 84W AND OVER PORTIONS OF CENTRAL AMERICA. HOWEVER...UPPER LEVEL DIFFLUENCE ON THE EASTERN PERIPHERY OF THE UPPER LEVEL RIDGE IS GENERATING SCATTERED SHOWERS AND ISOLATED TSTMS N OF 14N BETWEEN 78W-84W AND ACROSS PORTIONS OF CUBA. THIS ACTIVITY EXTENDS S-SW ACROSS INTERIOR EASTERN HONDURAS... NICARAGUA AND NORTHERN COSTA RICA. E OF 76W...AN UPPER LEVEL TROUGH EXTENDS WESTWARD FROM AN UPPER LEVEL LOW CENTERED OVER THE LEEWARD ISLANDS NEAR 17N60W. PRIMARILY DRY AIR ALOFT IS NOTED ACROSS THE EASTERN CARIBBEAN ON WATER VAPOR IMAGERY. MODERATE TRADE WINDS CONTINUE TO USHER IN ISOLATED LOW-LEVEL SHOWERS E OF 74W THIS EVENING. ELSEWHERE...THE ITCZ AXIS EXTENDS ACROSS PANAMA ALONG 8N AND IS GENERATING SCATTERED SHOWERS AND ISOLATED TSTMS S OF 10N BETWEEN 77W-81W. ATLANTIC OCEAN... A DISSIPATING STATIONARY FRONT EXTENDS SW TO THE CENTRAL FLORIDA PENINSULA FROM A 1013 MB LOW CENTERED NEAR 32N77W. LOW-LEVEL CONVERGENCE NEAR THE BOUNDARY IS GENERATING ISOLATED SHOWERS WITHIN 90 NM EITHER SIDE OF THE FRONT. THE REMAINDER OF THE W ATLC IS CONTROLLED BY A BROAD SURFACE RIDGE ANCHORED BY A 1022 MB HIGH CENTERED NEAR 32N55W. THE SURFACE RIDGE IS SUPPORTED BY A STRONG UPPER LEVEL ANTICYCLONIC CIRCULATION CENTERED NEAR 29N62W. UPPER LEVEL DIFFLUENCE BETWEEN THE UPPER LEVEL RIDGE AND AN UPPER LEVEL LOW CENTERED OVER THE LEEWARD ISLANDS NEAR 17N60W IS SUPPORTING A SURFACE TROUGH ALONG 63W EXTENDING FROM 20N-25N. ISOLATED SHOWERS COVER THE AREA FROM 19N-26N BETWEEN 60W-65W IN THE VICINITY OF THE SURFACE TROUGH. FARTHER E...A COLD FRONT ENTERS THE DISCUSSION AREA NEAR 32N23W EXTENDING SW ALONG 25N28W TO 23N37W. ISOLATED SHOWERS ARE N OF 27N BETWEEN 18W-22W. THE FRONT IS SUPPORTED ALOFT BY AN UPPER LEVEL TROUGH REMAINING N OF 20N E OF 40W WITH AXIS ALONG 32N21W 25N27W TO 22N40W. AN UPPER LEVEL RIDGE COVERS THE REMAINDER OF THE TROPICAL ATLC S OF 20N E OF 40W. THIS UPPER RIDGE CONTINUES TO ENHANCE THE CONVECTION ASSOCIATED WITH THE TROPICAL WAVE ALONG 24W. $$ HUFFMAN