000 AXNT20 KNHC 240605 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 205 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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 0530 UTC. ...SPECIAL FEATURE... TROPICAL STORM JERRY AT 24/0300 UTC WAS CENTERED NEAR 37.4N 46.1W OR ABOUT 910 NM W OF THE AZORES...MOVING N AT 7 KT. ESTIMATED MINIMUM CENTRAL PRESSURE IS 1004 MB. MAXIMUM SUSTAINED WIND SPEED IS 35 KT WITH GUSTS TO 45 KT. SEE LATEST NHC FORECAST ADVISORY UNDER AWIPS/WMO HEADERS MIATCMAT1/WTNT21 FOR MORE DETAILS. JERRY IS A SHEARED TROPICAL CYCLONE WITH LIMITED DEEP CONVECTION. THE STORM IS EXPECTED TO ACCELERATE TO THE NE SOON...AND EVENTUALLY GET ABSORBED INTO THE LARGE EXTRATROPICAL CYCLONE MOVING OFF THE CANADIAN MARITIMES IN ABOUT 24-36 HOURS. LITTLE CHANGE IN STRENGTH IS FORECAST DURING THE NEXT 24 HOURS. A WELL DEFINED TROPICAL WAVE IS LOCATED ALONG 57W OR ABOUT 175 NM E OF THE SOUTHERN WINDWARD ISLANDS. THE WAVE IS REPRESENTED WELL BY THE SURROUNDING SURFACE OBSERVATIONS...AND A QUIKSCAT PASS FROM 23/2200 UTC. THIS WAVE IS GENERATING SCATTERED SHOWER AND TSTM ACTIVITY FROM 9N-15N BETWEEN 53W-62W. THIS ACTIVITY WILL SPREAD THROUGH THE WINDWARD ISLANDS THROUGH MONDAY BRINGING SQUALLY WEATHER TO THE AREA...AND POSSIBLY TO THE LEEWARD ISLANDS BY TUESDAY. THIS SYSTEM HAS CHANGED LITTLE IN ORGANIZATION OVER THE PAST DAY...BUT HAS THE POTENTIAL TO DEVELOP INTO A TROPICAL DEPRESSION DURING THE NEXT DAY OR SO. INTERESTS IN THE LESSER ANTILLES SHOULD MONITOR THE PROGRESS OF THIS SYSTEM. A 1007 MB LOW PRESSURE SYSTEM IS LOCATED ABOUT 565 NM SSW OF THE CAPE VERDE ISLANDS NEAR 8N31W. THIS LARGE SYSTEM CONTINUES TO SHOW SIGNS OF ORGANIZATION...AND COULD BECOME A TROPICAL DEPRESSION DURING THE NEXT DAY OR TWO AS IT MOVES WEST-NORTHWESTWARD AT ABOUT 10-15 KT. THE MOST CONCENTRATED AREA OF SCATTERED MODERATE CONVECTION IS S OF THE CENTER FROM 5N-8N BETWEEN 28W-35W. ISOLATED CLUSTERS OF MODERATE CONVECTION ARE ELSEWHERE FROM 4N-15N BETWEEN 26W-36W. 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 37W 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 AND IS BY FAR THE DOMINANT FEATURE IN THE AREA. MOST OF THE REMAINING SHOWER/TSTM ACTIVITY ASSOCIATED WITH THE WAVE IS SCATTERED FROM 11N-13N BETWEEN 36W-40W. TROPICAL WAVE IS IN THE W CARIBBEAN ALONG 83W/84W 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 CURRENTLY MINIMAL. ...THE ITCZ... ITCZ AXIS IS CENTERED ALONG 12N15W 8N28W 6N40W 11N56W 10N62W. BESIDES THE ACTIVITY ASSOCIATED WITH THE SPECIAL FEATURES AND TROPICAL WAVE... SCATTERED MODERATE TO ISOLATED STRONG CONVECTION IS ALONG AND JUST OFFSHORE THE COAST OF AFRICA FROM 12N-15N BETWEEN 15W-18W. SIMILAR ACTIVITY IS FURTHER S FROM 4N-10N BETWEEN 11W-16W...AND NEAR 6N19W. THIS ACTIVITY MAY BE ASSOCIATED WITH THE NEXT TROPICAL WAVE. DISCUSSION... GULF OF MEXICO... ABUNDANT DEEP LAYER MOISTURE AND DISORGANIZED SHOWER ACTIVITY ARE OVER THE GULF WATERS E OF 92W. THE MOST CONCENTRATED SHOWER/TSTM ACTIVITY IS JUST OFF THE YUCATAN PENINSULA FROM 21N-23N BETWEEN 89W-92W...AND ALSO A COUPLE HUNDRED MILES OFFSHORE FLORIDA FROM 25N-28N BETWEEN 84W-87W. THE CLUSTER OFFSHORE THE YUCATAN IS MOSTLY CLOSELY ASSOCIATED TO THE BROAD SURFACE TROUGH IN THE VICINITY...AND RECENT SHORTWAVE IR IMAGERY SUGGESTS A WEAK LOW MAY BE NEAR 21N91W. AS OF 24/0300 UTC THE SFC TROUGH WAS ANALYZED OVER THE WEST/CENTRAL GULF GENERALLY ALONG 91W S OF 27N. THE UPPER SUPPORT FOR THE MOISTURE E OF 92W CONSISTS OF DIFFLUENT FLOW BETWEEN AN UPPER TROUGH EXTENDING S THROUGH 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 TONIGHT. MUCH OF THE MOISTURE/SHOWER ACTIVITY THAT WAS IN THE NW CARIBBEAN RECENTLY HAS PUSHED NW OF THE AREA WITH THE ASSOCIATED TROUGH/WEAK SFC LOW NOW OVER THE GULF. HOWEVER...THERE DOES APPEAR TO BE SOME LINGERING SHOWER ACTIVITY W OF 86W. THE TAIL END OF THE LONG SFC TROUGH IN THE ATLC APPEARS TO BE GENERATING ISOLATED SHOWERS/TSTMS IN THE NE CARIBBEAN N OF 14N E OF 67W. 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 ZONE TO THE S OF TROPICAL STORM JERRY. THE ELONGATED TROUGH AXIS ENTERS THE AREA NEAR 31N45W AND CONTINUES SW THROUGH 24N55W 21N61W 17N63W. THE MOST PRONOUNCED LOW LEVEL CYCLONIC TURNING IS NOTED NEAR 22N60W...AND IS ACCOMPANIED BY A CLUSTER OF MODERATE CONVECTION FROM 21N-25N BETWEEN 57W-61W. WILL WAIT FOR VISIBLE IMAGERY TO PUT A LOW IN THIS VICINITY. ISOLATED SHOWER/TSTM ARE ELSEWHERE WITHIN 250 NM OF THE TROUGH. MODERATE RIDGING TAKES OVER IN THE E ATLC ANCHORED BY A 1025 MB CENTERED TO THE E OF THE AZORES NEAR 39N23W. THIS OVERALL 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 14N46W. THIS IS GENERATING SCATTERED MODERATE CONVECTION FROM 13N-16N BETWEEN 45W-48W. IN THE MID AND UPPER LEVELS...N/NW FLOW AROUND THE SE GULF HIGH IS ADVECTING MID-HIGH CLOUDINESS AND ISOLATED SHOWERS S/SE W OF 70W. 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 TROUGH IS PROVIDING SOME SUPPORT FOR THE WEAK LOW-LEVEL BOUNDARY IN THE CENTRAL ATLC 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 33N20W. 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 OVER AND TO THE W OF THE CANARY ISLANDS. $$ MW