000 AXNT20 KNHC 211123 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 805 AM EDT WED OCT 21 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 1015 UTC. ...TROPICAL WAVES... TROPICAL WAVE IS ALONG 29W FROM 7N-17N AND DRIFTING WESTWARD OVER THE PAST 24 HOURS. THE WAVE AXIS COINCIDES WITH A DEEP LAYER MOISTURE MAXIMUM AS OBSERVED IN TOTAL PRECIPITABLE WATER IMAGERY AS WELL AS A MAXIMUM IN 850 MB RELATIVE VORTICITY ON THE CIMSS GLOBAL MODEL GUIDANCE. THE LOW-LEVEL CLOUD FIELD EXHIBITS CYCLONIC TURNING IN THE VICINITY OF THE WAVE AXIS WITH ISOLATED SHOWERS AND MODERATE CONVECTION FROM 12N-18N BETWEEN 23W-30W WHICH INCLUDES THE CAPE VERDE ISLANDS. ...ITCZ... THE ITCZ AXIS IS CENTERED ALONG 10N14W 7N28W 7N31W 9N38W 10N44W 9N61W. A 1009 MB SURFACE LOW IS LOCATED N OF THE AXIS ACROSS THE CENTRAL TROPICAL ATLC CENTERED NEAR 13N40W. SCATTERED MODERATE CONVECTION IS FROM 11N-15N BETWEEN 35W-40W IN ASSOCIATION WITH THE LOW. ELSEWHERE...CLUSTERS OF ISOLATED MODERATE TO STRONG CONVECTION COVER THE AREA FROM 2N-7N BETWEEN 18W-34W. ...DISCUSSION... GULF OF MEXICO... A BROAD SURFACE RIDGE DOMINATES ACROSS FLORIDA AND THE GULF... ANCHORED OVER THE CAROLINAS BY A 1025 MB HIGH. ALOFT...THE GULF IS INFLUENCED BY W-NW ANTICYCLONIC FLOW AROUND AN UPPER LEVEL RIDGE THAT IS ANCHORED BY AN UPPER HIGH CENTERED OVER SRN MEXICO NEAR 17N98W. STRONG SUBSIDENCE AND DRY STABLE AIR IS NOTED ON WATER VAPOR IMAGERY PRIMARILY E OF 87W...WHILE UPPER LEVEL CONVECTIVE DEBRIS CLOUDINESS FROM TROPICAL STORM RICK IN THE EASTERN PACIFIC ADVECTS EASTWARD AND SPILLS OVER THE TOP OF THE UPPER LEVEL RIDGE N OF 25N W OF 92W. AT THE SURFACE HOWEVER...E TO SE SURFACE FLOW UP TO 20 KT IS FORECAST TO CONTINUE THROUGH WEDNESDAY...TURNING MORE SOUTHERLY OVER THE WESTERN GULF BY THURSDAY AHEAD OF THE NEXT COLD FRONT EXPECTED TO ENTER THE NW GULF WATERS LATE THURSDAY. CARIBBEAN SEA... A DEEP LAYERED TROUGH IS OVER THE W ATLC AND FLORIDA PENINSULA THAT DIPS S OVER THE NW CARIBBEAN AND WESTERN CUBA. A 1008 MB LOW IS CENTERED INLAND OVER COSTA RICA NEAR 10N84W AND EXTENDS SURFACE TROUGHING N-NW TO A 1010 MB LOW IN THE GULF OF HONDURAS NEAR 18N87W. AN UPPER LEVEL RIDGE IS LOCATED TO THE E EXTENDING FROM NORTHERN COLOMBIA NEAR 11N75W TO ACROSS EASTERN HISPANIOLA AND INTO THE W ATLC. THIS IS PROVIDING A DIFFLUENT ENVIRONMENT ALOFT ACROSS THE SW CARIBBEAN THAT IS ENHANCING A BROAD AREA OF SCATTERED SHOWERS AND ISOLATED TSTMS FOCUSED MAINLY E OF THE SURFACE TROUGH OVER COSTA RICA...NICARAGUA AND EASTERN HONDURAS. THIS ACTIVITY COVERS THE WESTERN CARIBBEAN W OF A LINE FROM COLOMBIA NEAR 10N76W TO JAMAICA AND NORTHEASTWARD TO THE WINDWARD PASSAGE NEAR 20N73W. A BROAD UPPER LEVEL TROUGH COVERS THE EASTERN CARIBBEAN EXTENDING FROM AN UPPER LOW IN THE CENTRAL ATLC PROVIDING STRONG SUBSIDENCE AND DRY STABLE AIR E OF 70W. ATLANTIC OCEAN... A BROAD DEEP LAYERED UPPER LEVEL TROUGH COVERS MUCH OF THE SW NORTH ATLC...FLORIDA PENINSULA AND STRAITS OF FLORIDA WITH THE ASSOCIATED COLD FRONT ENTERING THE REGION NEAR 32N56W SW TO 28N60W WHERE IT BECOMES STATIONARY ALONG 25N65W TO NORTH OF HISPANIOLA NEAR 20N71W. SCATTERED SHOWERS ARE OCCURRING WITHIN 300 NM BEHIND THE FRONT WITH LOW-LEVEL CONVERGENCE E OF THE FRONT GENERATING ISOLATED SHOWERS WITHIN 90 NM E OF THE FRONT. AN UPPER RIDGE EXTENDS FROM THE WESTERN CARIBBEAN THROUGH EASTERN HISPANIOLA ALONG 24N62W TO 32N52W PROVIDING DIFFLUENCE ALOFT NW OF THE UPPER RIDGE AXIS THAT IS ENHANCING THE ACTIVITY ASSOCIATED WITH THE FRONTAL BOUNDARY. FARTHER EAST...A BROAD UPPER LEVEL LOW IS CENTERED IN THE CENTRAL ATLC NEAR 24N49W WITH UPPER LEVEL TROUGHING EXTENDING SW TO THE LESSER ANTILLES AND EASTERN CARIBBEAN. THIS SUPPORTS A SURFACE TROUGH THAT EXTENDS FROM 19N58W TO 29N52W WITH A 1009 MB SURFACE LOW CENTERED ALONG THE SURFACE TROUGH NEAR 24N53W. POSSIBLE ISOLATED SHOWERS ARE WITHIN 120 NM EITHER SIDE OF THE SURFACE TROUGH. UPPER LEVEL DIFFLUENCE E OF THE UPPER LEVEL LOW HOWEVER IS GENERATING A MUCH MORE ACTIVE AREA OF SCATTERED SHOWERS AND ISOLATED TSTMS COVERING THE AREA FROM 23N-30N BETWEEN 37W-49W. ACROSS THE REMAINDER OF THE ATLC...A BROAD UPPER RIDGE IS LOCATED OVER THE TROPICAL ATLC ANCHORED NEAR 8N41W THAT EXTENDS A RIDGE AXIS N TO 25N25W. ALSO A WEAKENING COLD FRONT SKIRTS THE NE PORTION OF THE DISCUSSION AREA ALONG 30N E OF 23W THAT IS BRINGING POSSIBLE ISOLATED SHOWERS TO THE CANARY ISLANDS AND THE COAST OF WESTERN MOROCCO. $$ HUFFMAN