000 AXNT20 KNHC 272342 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 805 PM EDT TUE OCT 27 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 EXTENDS FROM 16N25W TO 13N27W TO 8N27W MOVING W NEAR 10 KT. SATELLITE IMAGERY INDICATES CYCLONIC LOW-LEVEL FLOW ALONG THE WAVE AXIS FOCUSED NEAR 13N. THIS ALSO COINCIDES WITH CIMSS WAVETRAK 850 MB RELATIVE VORTICITY MODEL GUIDANCE WHICH COVERS THE AREA FROM 10N-15N BETWEEN 22W-28W. TOTAL PRECIPITABLE WATER IMAGERY DEPICTS A MAXIMUM IN DEEP LAYER MOISTURE FROM 8N-20N E OF 30W WHICH ALSO ENCOMPASSES THE WAVE. SCATTERED MODERATE CONVECTION IS FROM 11N-18N BETWEEN 19W-28W. THIS CONVECTION IS LARGELY BEING SHEARED TO THE NE OF THE WAVE AXIS DUE TO AN UPPER LEVEL TROUGH DIGGING SOUTHWARD BETWEEN 20W-30W N OF 17N OVER THE NE ATLC. TROPICAL WAVE IS ALONG 48W S OF 16N MOVING W NEAR 12 KT. CIMSS WAVETRACK MODEL GUIDANCE DEPICTS AN AREA OF MAXIMUM 850 MB RELATIVE VORTICITY NEAR THE WAVE AXIS FROM 5N-10N BETWEEN 45W-52W. SATELLITE IMAGERY INDICATES BROAD CYCLONIC FLOW IN THE VICINITY OF THE WAVE AXIS WITH MOST MOISTURE REMAINING EMBEDDED WITHIN THE ITCZ AXIS ALONG 9N. NO DEEP CONVECTION IS OBSERVED HOWEVER SCATTERED SHOWERS ARE FROM 5N-11N BETWEEN 45W-51W. TROPICAL WAVE IS ALONG 61W S OF 17N MOVING W NEAR 13 KT. THE WAVE COINCIDES WITH A MAXIMUM IN DEEP LAYER MOISTURE AS OBSERVED IN TOTAL PRECIPITABLE WATER IMAGERY ACROSS THE EASTERN PORTION OF THE TROPICAL NORTH ATLC. CURRENTLY SCATTERED SHOWERS AND ISOLATED MODERATE CONVECTION IS FROM 14N-18N BETWEEN 58W-62W AND IMPACTING THE LEEWARD ISLANDS THIS EVENING. THIS ACTIVITY IS LIKELY BEING ENHANCED BY UPPER DIFFLUENT FLOW ALOFT DUE TO AN UPPER LEVEL LOW CENTERED OVER THE N/CENTRAL CARIBBEAN NEAR 17N70W. ...ITCZ... THE ITCZ AXIS IS CENTERED ALONG 9N13W 10N25W 9N29W 9N46W 9N49W 10N59W. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS ALONG THE W AFRICA COAST FROM 6N-11N BETWEEN 8W-14W. ...DISCUSSION... GULF OF MEXICO... A COLD FRONT EXTENDS INTO THE GULF FROM SOUTHERN MISSISSIPPI NEAR 30N89W ALONG 27N90W TO 24N93W WHERE IT CONTINUES STATIONARY S ALONG 20N94W INTO SOUTHERN MEXICO NEAR 18N94W. ISOLATED SHOWERS ARE WITHIN 200 NM EITHER SIDE OF THE FRONT. SCATTERED SHOWERS AND ISOLATED TSTMS ARE ALSO WELL EAST OF THE FRONT FOCUSED ALONG A LOW-LEVEL CONVERGENCE BOUNDARY OCCURRING WITHIN 90 NM EITHER SIDE OF A LINE FROM JACKSONVILLE FLORIDA SW TO THE YUCATAN PENINSULA NEAR 19N89W. THIS FRONTAL SYSTEM IS SUPPORTED ALOFT BY MOIST SWLY FLOW BETWEEN AN UPPER LEVEL TROUGH OVER THE SOUTHERN U.S. PLAINS AND AN UPPER LEVEL RIDGE EXTENDING FROM NORTHERN GUATEMALA NE OVER THE YUCATAN CHANNEL AND SOUTHERN FLORIDA PENINSULA INTO THE W ATLC NEAR 28N78W. AS THE COLD FRONT MOVES EASTWARD AND BECOMES MORE DIFFUSE OVER THE NE GULF BY WEDNESDAY...SOUTHERLY RETURN FLOW IS EXPECTED AGAIN ACROSS THE WESTERN GULF AHEAD OF THE NEXT DEVELOPING COLD FRONT TO ENTER THE NW GULF LATE THURSDAY. CARIBBEAN SEA... A MAJORITY OF THE CARIBBEAN SEA IS EXPERIENCING GENERALLY FAIR WEATHER THIS EVENING DUE IN PART TO AN UPPER LEVEL LOW CENTERED SOUTH OF HISPANIOLA NEAR 17N70W. THIS UPPER LEVEL LOW IS PROVIDING GENERALLY DRY NLY UPPER LEVEL FLOW W OF 73W ACROSS THE NW CARIBBEAN. UPPER LEVEL DIFFLUENCE S OF 13N W OF 75W HOWEVER...IS GENERATING SCATTERED SHOWERS AND ISOLATED TSTMS OVER THE SW CARIBBEAN...INCLUDING PANAMA...COSTA RICA AND SOUTHERN NICARAGUA. EAST OF THE UPPER LEVEL LOW...UPPER LEVEL DIFFLUENCE IS GENERATING ISOLATED SHOWERS N OF 16N E OF 70W. THIS UPPER LEVEL DIFFLUENT PATTERN IS ALSO ENHANCING THE SHOWER ACTIVITY ASSOCIATED WITH THE TROPICAL WAVE ALONG 61W. MODERATE TO FRESH TRADEWINDS ARE OBSERVED ACROSS THE MAJORITY OF THE BASIN THIS EVENING. ATLANTIC OCEAN... A WARM FRONT ENTERS THE FAR NW PORTION OF THE DISCUSSION AREA ACROSS THE W ATLC NEAR 32N79W AND EXTENDS WSW TO INLAND OVER SOUTHERN GEORGIA NEAR 31N81W. SCATTERED SHOWERS ARE N OF 28N W OF 79W MAINLY SOUTH OF THE WARM FRONT ACROSS THE NORTHERN FLORIDA PENINSULA. THE FRONT IS SUPPORTED LARGELY BY AN AREA OF UPPER LEVEL DIFFLUENCE THAT COVERS MUCH OF THE NE GULF OF MEXICO ACROSS NORTHERN FLORIDA AND INTO THE FAR W ATLC. AN UPPER LEVEL RIDGE AXIS IS TO THE E EXTENDING FROM THE SOUTHERN FLORIDA PENINSULA NE TO BEYOND 32N75W. THIS UPPER RIDGE ALSO EXTENDS A RIDGE AXIS EASTWARD ALONG 27N THAT SUPPORTS A BROAD SURFACE RIDGE COVERING THE MAJORITY OF THE CENTRAL ATLC ANCHORED BY A 1020 MB HIGH CENTERED NEAR 30N64W. A COLD FRONT LIES NORTH OF THE SURFACE RIDGE ALONG 32N BETWEEN 45W-62W. WIDELY SCATTERED SHOWERS ARE WITHIN 90 NM EITHER SIDE OF THE FRONT AND CONTINUE TO BECOME MORE DIFFUSE REACHING 30N. FARTHER E...A DISSIPATING COLD FRONT EXTENDS FROM 22N28W TO 28N20W TO BEYOND 32N19W. POSSIBLE ISOLATED SHOWERS ARE WITHIN 75 NM E OF THE BOUNDARY. A SHORTWAVE UPPER LEVEL TROUGH WITH AXIS ALONG 32N19W TO 19N30W SUPPORTS THE FRONT AS IT MOVES ACROSS THE NE ATLC. $$ HUFFMAN