000 AXNT20 KNHC 011805 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 205 PM EDT THU NOV 01 2007 TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL AMERICA...THE GULF OF MEXICO...THE CARIBBEAN SEA...NORTHERN SECTIONS OF SOUTH AMERICA...AND THE 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 1715 UTC. ...SPECIAL FEATURE... THE CENTER OF TROPICAL STORM NOEL WAS CENTERED NEAR 25.0N 77.4W AT 01/1800 UTC OR NEAR NASSAU BAHAMAS...NOW MOVING TOWARD THE N-NE NEAR 12 KT. ESTIMATED MINIMUM CENTRAL PRESSURE IS 993 MB. MAXIMUM SUSTAINED WIND SPEED ARE 55 KT WITH GUSTS TO 65 KT. SOME ADDITIONAL STRENGTHENING IS POSSIBLE LATER TODAY. SEE THE NHC FORECAST ADVISORY UNDER AWIPS/WMO HEADERS MIATCMAT1/WTNT21 KNHC AND THE PUBLIC ADVISORY UNDER MIATCPAT1/WTNT31 KNHC FOR MORE DETAILS. NUMEROUS MODERATE TO STRONG CONVECTION ASSOCIATED WITH THE SYSTEM IS MOSTLY LIMITED TO WITHIN 180 NM NE SEMICIRCLE. SIGNIFICANT RAINFALL ACCUMULATIONS ARE EXPECTED OVER PORTIONS OF THE BAHAMAS...WITH MINIMAL ACCUMULATIONS EXPECTED OVER SE FLORIDA. A TROPICAL STORM WARNING REMAINS IN EFFECT FOR THE CENTRAL AND NW BAHAMAS. THE WARNING FOR SE FLORIDA HAS BEEN DISCONTINUED. THE STORM IS EXPECTED TO ACCELERATE TO THE NE AND BECOME EXTRATROPICAL IN ABOUT 36 HRS. WHILE THE STORM IS EXPECTED TO MOVE AWAY FROM FLORIDA...THE MARINE THREAT WILL NOT END. STRONG N WINDS AND LARGE NE SWELLS ARE EXPECTED TO PERSIST THROUGH MUCH OF THE UPCOMING WEEKEND...AS NOEL BECOMES AN INTENSE EXTRATROPICAL CYCLONE OVER THE NW ATLC AND INTERACTS WITH STRONG HIGH PRESSURE OVER THE MIDDLE AND EASTERN PORTIONS OF THE UNITED STATES. SEE HIGH SEAS FORECAST UNDER AWIPS HEADER NFDHSFAT1 AND STATEMENTS FROM LOCAL WEATHER OFFICES FOR DETAILS. ...TROPICAL WAVES... TROPICAL WAVE IS IN THE CENTRAL CARIBBEAN ALONG 74W/75W S OF 18N MOVING W 5-10 KT OVER THE PAST 24 HOURS. IT IS DIFFICULT TO TELL EXACTLY WHERE THIS WAVE IS LOCATED AS MUCH OF THE ASSOCIATED ENERGY HAS BECOME EMBEDDED WITHIN THE CLOUDINESS ASSOCIATED WITH THE TRAILING TROUGH OF NOEL. THE MIMIC TPW ANIMATION SHOWS A WWD MOVING SURGE OF DRY AIR WORKING ITS WAY ACROSS THE CARIB BEHIND THE WAVE OVER THE LAST 48 HOURS. HOWEVER...GIVEN THAT THE FLOW AROUND NOEL AND ITS TRAILING TROUGH HAVE UNDOUBTEDLY TAKEN OVER THE FLOW IN THE REGION...THE WAVE WILL LIKELY BE DROPPED FROM THE 1800 UTC MAP. ...THE ITCZ... ITCZ AXIS IS CENTERED ALONG 10N14W 8N22W 5N33W 8N43W 4N53W. SCATTERED MODERATE CONVECTION IS WITHIN 220NM EITHER SIDE OF THE AXIS BETWEEN 18W-24W. SIMILAR ACTIVITY IS WITHIN 150NM N AND 90NM S OF THE AXIS BETWEEN 24W-32W. A TROUGH IS EMBEDDED IN THE ITCZ ALONG 40/41W FROM 5N-16N...THAT IS GENERATING ISOLATED SHOWERS/TSTMS WITHIN 90 NM OF THE AXIS. THIS MAY ACTUALLY BE THE TROPICAL WAVE THAT APPEARS TO HAVE PASSED DAKAR AROUND 12Z OCT 27. HOWEVER...GIVEN ITS RATHER POOR SATELLITE APPEARANCE HAVE OPTED TO MAKE THE FEATURE A TROUGH. DISCUSSION... GULF OF MEXICO... TIGHT PRES GRADIENT BETWEEN TROPICAL STORM NOEL AND STRONG HIGH PRES TO ITS N IS KEEPING N TO NE WINDS STRONG ACROSS THE E GULF AS NOTED IN BUOY DATA AND RECENT SCATTEROMETER PASSES. WINDS GENERALLY RELAX IN THE W GULF AS THE GRADIENT SLACKENS. MOSAIC DOPPLER RADAR SHOWS BROKEN UP BANDS OF NOEL PUSHING ACROSS S AND CENTRAL FLORIDA AND THE STRAITS. MOST OF THIS ACTIVITY THINS OUT EVEN FURTHER AS IT TRAVERSES INTO THE GULF. THE FLOW ALOFT IS FAIRLY ZONAL TO THE N OF A FLAT UPPER RIDGE CENTERED OVER THE CARIBBEAN. A WEAK SHORTWAVE TROUGH OVER THE FLORIDA PENINSULA IS BENDING THE UPPER FLOW MORE NW/WNW IN THE ERN GULF. THIS SHORTWAVE AND A STRONGER ONE TO FOLLOW WILL BE THE STEERING ELEMENTS CAUSING NOEL TO ACCELERATE TOWARD THE NE. WATER VAPOR IMAGERY REVEALS WIDESPREAD DRY AIR ACROSS THE REGION WHICH IS HELPING TO SUPPRESS SIGNIFICANT SHOWER ACTIVITY...ESPECIALLY S OF 27N. CARIBBEAN SEA... SATELLITE IMAGERY AND DOPPLER RADAR DATA FROM CAMAGUEY CUBA REVEAL HEAVY RAINS OVER THE ERN PORTION OF THE COUNTRY. ADDITIONAL RAINFALL ACCUMULATIONS OF 2 TO 4 INCHES ARE EXPECTED OVER EASTERN CUBA AND HISPANIOLA...WHERE THESE RAINS COULD CAUSE LIFE-THREATENING FLASH FLOODS AND MUD SLIDES. THE COMBINATION OF A TRAILING TROUGH HANGING SWD FROM TROPICAL STORM NOEL...ALONG 21N80W 10N79W...IS GENERATING SCATTERED SHOWERS AND TSTMS GENERALLY BETWEEN 73W AND 83W. THE STRONGEST SMALL CLUSTERS ARE CURRENTLY LOCATED BETWEEN THE CAYMAN ISLANDS AND THE SW TIP OF HAITI. ANOTHER CLUSTER OF MODERATE CONVECTION IS NEAR THE GULF OF HONDURAS WITHIN 60NM OF 17N85W. THE AIR DRIES OUT SOME TO OVER THE FAR NW CARIBBEAN DRIVEN BY FRESH NWLY WINDS. THE E CARIB IS FAIRLY TRANQUIL UNDER MODERATE TRADE WIND FLOW AND DRIER MID/UPPER AIR ADVECTED INTO THE REGION BY NLY WINDS BETWEEN AN UPPER LOW E OF THE AREA AND AN UPPER HIGH CENTERED BETWEEN HISPANIOLA AND COLOMBIA. ATLANTIC OCEAN... THE MAIN STORY IS TROPICAL STORM NOEL WHICH HAS BEGUN ITS TURN TO THE N-NE NEAR THE WESTERN BAHAMAS. FOR STORM SPECIFICS SEE THE SPECIAL FEATURE SECTION ABOVE. IN ADDITION TO THE WIND FIELD DIRECTLY ASSOCIATED WITH NOEL...THE TIGHT PRES PATTERN SET UP BETWEEN THE TROPICAL STORM AND STRONG HIGH PRES NE OF BERMUDA IS PRODUCING STRONG GUSTY WINDS...OCCASIONALLY TO GALE FORCE W OF 70W...AND LARGE SEAS OVER MUCH OF THE WRN ATLC. A JASON ALTIMETER PASS FROM EARLY THIS MORNING REVEALED SEAS OF 12-14 FT OVER THE STRAITS OF FLORIDA...WHICH WAS UNDERDONE BY ALL AVAILABLE WAVE MODEL GUIDANCE. STRONG WINDS AND LARGE SEAS EXPECTED TO PERSIST OVER THE WRN PORTION OF THE AREA OVER THE NEXT COUPLE OF DAYS AS NOEL TRANSITIONS TO A POWERFUL EXTRATROPICAL STORM. DEBRIS MOISTURE FROM NOEL'S CONVECTIVE MASS STRETCHES FAR TO THE E ROUGHLY N OF 23N W OF ABOUT 55W. THIS MOISTURE IS THEN FEEDING INTO THE MOISTURE ASSOCIATED WITH AN UPPER TROUGH NEAR 50W N OF 25N. THIS TROUGH IS PROVIDING SOME SUPPORT FOR A SLOW MOVING FRONTAL BOUNDARY WHICH ENTERS THE AREA NEAR 32N35W AND EXTENDS MAINLY W ALONG 27N44W 28N67W. THE FRONT IS HELPING TO TIGHTEN THE GRADIENT...WITH THIS MORNINGS QUIKSCAT PASS SHOWING NE/E WINDS 20-30 KT BEHIND THE BOUNDARY. A CUT-OFF UPPER LOW IN THE TROPICAL ATLC NEAR 11N53W IS PRODUCING A SMALL AREA OF CLOUDINESS AND ISOLATED SHOWERS FROM 10N-14N BETWEEN 49W-53W. AN UPPER SW TO WLY JET EXISTS TO THE E OF THIS UPPER LOW AND STRETCHES E TO THE COAST OF SENEGAL. THE REMAINDER OF THE E ATLC IS FAIRLY QUIET UNDER MODERATE SFC RIDGING AND AN ELONGATED UPPER RIDGE/TROUGH PATTERN. $$ WILLIS