000 AXNT20 KNHC 241032 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 805 AM EDT MON SEP 24 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 1015 UTC. ...SPECIAL FEATURE... TROPICAL STORM JERRY AT 24/0900 UTC WAS CENTERED FAR FROM LAND NEAR 38.6N 45.4W...OR ABOUT 865 NM W OF THE AZORES...MOVING N-NE AT 13 KT. ESTIMATED MINIMUM CENTRAL PRESSURE IS 1004 MB. MAXIMUM SUSTAINED WINDS ARE 35 KT WITH GUSTS TO 45 KT. SEE LATEST NHC FORECAST ADVISORY UNDER AWIPS/WMO HEADERS MIATCMAT1/WTNT21 FOR MORE DETAILS. THE REMAINING SCATTERED MODERATE CONVECTION ASSOCIATED WITH THE SYSTEM IS CONFINED MOSTLY IN A BROKEN UP BAND IN THE EASTERN SEMICIRCLE...FROM 36N-41N BETWEEN 44W-46W. JERRY IS EXPECTED TO BE ABSORBED BY A LARGER NON-TROPICAL LOW PRESSURE SYSTEM BY TUESDAY MORNING. A WELL DEFINED TROPICAL WAVE IS LOCATED ALONG 58W OR ABOUT 85 NM E OF THE SOUTHERN WINDWARD ISLANDS. A SFC LOW WILL LIKELY BE ADDED TO THE WAVE AXIS ON THE 24/1200 UTC MAP...WITH A CLOSED CYCLONIC SWIRL NOW APPARENT JUST SE OR BARBADOS VIA SHORTWAVE IR IMAGERY. WINDS AT GRANTLEY ADAMS INTERNATIONAL AIRPORT IN SE BARBADOS ALSO RECENTLY BACKED TO THE NW WITH THE APPROACH OF THIS LOW. THIS WAVE IS GENERATING SCATTERED SHOWER AND ISOLATED TSTM ACTIVITY FROM 9N-16N BETWEEN 52W-61W. THIS ACTIVITY WILL SPREAD THROUGH THE WINDWARD ISLANDS THROUGH LATER TODAY...BRINGING SQUALLY WEATHER TO THE AREA...AND POSSIBLY TO THE LEEWARD ISLANDS ON TUESDAY. THUNDERSTORM ACTIVITY HAS DECREASED OVERNIGHT WITH THIS SYSTEM...BUT IT STILL HAS THE POTENTIAL TO DEVELOP INTO A TROPICAL DEPRESSION DURING THE NEXT DAY OR TWO AS IT MOVES NORTHWESTWARD AT ABOUT 10-15 KT. INTERESTS IN THE LESSER ANTILLES SHOULD MONITOR THE PROGRESS OF THIS SYSTEM. A 1007 MB LOW PRESSURE SYSTEM IS LOCATED ABOUT 565 NM SW OF THE CAPE VERDE ISLANDS NEAR 8.5N31W. THIS LARGE SYSTEM CONTINUES TO SHOW SIGNS OF ORGANIZATION...AND COULD BECOME A TROPICAL DEPRESSION DURING THE NEXT DAY OR SO AS IT MOVES WEST-NORTHWESTWARD NEAR 10-15 KT. A MORE CONCENTRATED AREA OF SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS NOW MOSTLY W OF THE CENTER FROM 8N-11N BETWEEN 31W-37W. ISOLATED CLUSTERS OF MODERATE CONVECTION ARE ELSEWHERE FROM 5N-12N BETWEEN 29W-38W. THIS IS ONE OF THE MORE CLASSIC LOOKING CAPE VERDE SYSTEMS WE HAVE SEEN OVER THE PAST COUPLE OF WEEKS. ...TROPICAL WAVES... TROPICAL WAVE IS ALONG 38W S OF 18N MOVING W 10-15 KT. THIS WAVE HAS MAINTAINED GOOD WWD CONTINUITY IN BOTH SATELLITE HOVMOLLER DIAGRAMS AND THE MIMIC TPW ANIMATION SINCE EMERGING OFF THE COAST OF AFRICA A FEW DAYS AGO. HOWEVER...THE LARGE LOW PRESSURE SYSTEM E OF THE WAVE...ERN MOST SPECIAL FEATURE DISCUSSED ABOVE...CONTINUES TO OVERTAKE THIS WAVE. THE REMAINING SHOWER/TSTM ACTIVITY ASSOCIATED WITH THE WAVE IS LIMITED...WITH ISOLATED CELLS OF MODERATE CONVECTION NOTED FROM 11N-13N BETWEEN 37W-42W. THIS WAVE MAY NEED TO BE DROPPED OR RELOCATED ALONG THE BETTER DEFINED LOW JUST TO ITS E...WHICH APPEARS TO BE ABSORBING THE WAVE WE HAVE BEEN TRACKING THE LAST FEW DAYS. TROPICAL WAVE IS IN THE W CARIBBEAN ALONG 85W S OF 19N MOVING W 10-15 KT. THE WAVE IS NOT EASILY SEEN IN ANY OF THE AVAILABLE DATA AND CONTINUES TO FOLLOW CONTINUITY FROM PREVIOUS ANALYSES. SHOWER ACTIVITY IN THE VICINITY IS OVERALL MINIMAL. A CLUSTER OF MODERATE CONVECTION IS JUST OFFSHORE BELIZE...BUT THIS MAY BE MORE ASSOCIATED WITH THE UPPER HIGH OVER THE AREA. ...THE ITCZ... ITCZ AXIS IS CENTERED ALONG 7N11W 9N20W 9N30W 7N43W 13N55W 9N62W. BESIDES THE ACTIVITY ASSOCIATED WITH THE SPECIAL FEATURES/TROPICAL WAVES...SCATTERED MODERATE TO ISOLATED STRONG CONVECTION IS JUST OFFSHORE THE COAST OF AFRICA FROM 4N-9N BETWEEN 12W-22W. THIS ACTIVITY MAY BE ASSOCIATED WITH THE NEXT TROPICAL WAVE. THE STRONGER CLUSTER THAT MOVED OFF THE COAST OF SENEGAL LAST NIGHT HAS DIMINISHED A BIT...THOUGH SCATTERED MODERATE REMAINS FROM 13N-15N BETWEEN 19W-21W. DISCUSSION... GULF OF MEXICO... ABUNDANT DEEP LAYER MOISTURE AND DISORGANIZED SHOWER ACTIVITY ARE OVER THE GULF WATERS BETWEEN 86W-94W. THE MOST CONCENTRATED SHOWER/TSTM ACTIVITY IS JUST OFF THE YUCATAN PENINSULA...WITH SCATTERED MODERATE CONVECTION FROM 21N-26N BETWEEN 89W-94W. THIS IS ASSOCIATED WITH THE BROAD SURFACE TROUGH AND WEAK LOW PRESSURE AREA OVER THE SW GULF. AS OF 24/0900 UTC...THE 1011 MB LOW WAS NEAR 22N93W...WITH A TROUGH EXTENDING THROUGH THE LOW FROM 19N91W TO 25N96W. UPPER-LEVEL WINDS ARE CURRENTLY STRONG OVER THE WESTERN GULF...BUT THEY COULD WEAKEN SOMEWHAT AND BECOME A LITTLE MORE FAVORABLE FOR DEVELOPMENT OF THIS SYSTEM AS IT MOVES SLOWLY WEST-NORTHWESTWARD DURING THE NEXT COUPLE OF DAYS. THE DISORGANIZED CONVECTION ASSOCIATED WITH THE SFC LOW IS ALSO BEING SUPPORTED BY DIFFLUENT FLOW ALOFT...BETWEEN AN UPPER TROUGH EXTENDING THROUGH ERN TEXAS AND NE MEXICO...AND UPPER RIDGING OVER THE ERN GULF. DEEP MOISTURE WITH SCATTERED SHOWER/TSTM ACTIVITY TO PERSIST ESPECIALLY BETWEEN 84W-96W...BETWEEN THE YUCATAN AND LOUISIANA...OVER THE NEXT DAY OR SO. CARIBBEAN SEA... NO ORGANIZED DEEP CONVECTION IS AFFECTING THE BASIN THIS MORNING. A FEW ISOLATED TSTMS ASSOCIATED WITH THE ITCZ ARE IN THE SW CARIB S OF 12N. THE TAIL END OF THE LONG SFC TROUGH IN THE ATLC APPEARS TO BE GENERATING ISOLATED SHOWERS/TSTMS IN THE NE CARIBBEAN N OF 13N E OF 70W. SHOWER ACTIVITY WILL INCREASE IN THE ERN PORTION OVER THE NEXT COUPLE OF DAYS WITH THE WELL DEFINED TROPICAL WAVE APPROACHING...SEE SPECIAL FEATURE SECTION ABOVE FOR DETAILS. TRADES ARE MOSTLY LIGHT EXCEPT MODERATE VELOCITIES STILL NOTED PER USUAL OVER THE CENTRAL PORTION FROM 11N-16N BETWEEN 67W-78W. THE UPPER PATTERN CONSISTS OF A FAIRLY WELL DEFINED RIDGE/TROUGH/RIDGE PATTERN. ATLANTIC OCEAN... MOST OF THE ACTIVE SFC FEATURES ARE DISCUSSED IN THE SPECIAL FEATURES SECTION ABOVE. ELSEWHERE AT THE SFC...WEAK HIGH PRES RIDGING CONTROLS THE W ATLC. TROUGHING DOMINATES MUCH OF THE CENTRAL ATLC AREA. AN ELONGATED SFC TROUGH IS ALONG 30N63W 24N62W TO THE NE CARIBBEAN NEAR 15N65W. SCATTERED SHOWERS/ISOLATED TSTMS ARE MOSTLY WITHIN 250NM E OF THE AXIS...MOST CONCENTRATED FROM 20N-26N. ANOTHER TROUGH...IS JUST TO E ALONG 30N44W 26N47W 24N54W. DECIDE TO BREAK THESE TWO TROUGHS THAT WERE PREVIOUSLY CONNECTED DUE TO ITS APPEARANCE IN SATELLITE IMAGERY AND RECENT QUIKSCAT DATA. MODERATE RIDGING TAKES OVER IN THE E ATLC ANCHORED BY A 1026 MB HIGH NEAR THE AZORES NEAR 38N25W. THIS PATTERN IS PRODUCING MODERATE TRADES IN THE E ATLC...EXCEPT STRONGER NEAR THE TYPICAL TIGHTENED GRADIENT NEAR THE COAST OF NW AFRICA. LIGHT TO MODERATE WINDS EXIST ELSEWHERE IN THE FAIRLY RELAXED GRADIENT. THE OTHER SFC FEATURE IS IN THE TROPICAL ATLC...WITH A 1012MB LOW NEAR 14N47W. THIS IS GENERATING SCATTERED SHOWERS/ISOLATED TSTMS FROM 12N-16N BETWEEN 45W-49W. IN THE MID AND UPPER LEVELS...N/NW FLOW AROUND RIDGING FROM THE GULF IS ADVECTING MID-HIGH CLOUDINESS AND ISOLATED SHOWERS S/SE...S OF 28N W OF 67W. THE FLOW FROM THE E GULF RIDGING FOLDS INTO A VERY BROAD TROUGH COVERING THE AREA BETWEEN 43W-75W....WITH A FEW EMBEDDED SHORTWAVES NOTED. THE OVERALL BROAD UPPER TROUGH IS PROVIDING SOME SUPPORT FOR THE WEAK LOW-LEVEL TROUGHING IN THE CENTRAL ATLC AS DISCUSSED ABOVE. AN AMPLIFIED UPPER RIDGE TAKES OVER E OF THE TROUGH WITH THE AXIS EXTENDING ROUGHLY N-S ALONG 37W. A LARGE UPPER LOW IS SITUATED E OF THE RIDGE W OF THE MADEIRA ISLANDS NEAR 33N19W. THIS LOW IS PROVIDING PRONOUNCED TROUGHING ACROSS THE NEARLY THE ENTIRE ATLC E OF 30W. SWLY FLOW ON THE E SIDE OF THE LOW IS GENERATING SCATTERED CLOUDINESS NEAR THE CANARY ISLANDS. $$ MW