000 AXNT20 KNHC 141040 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 805 AM EDT FRI SEP 14 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 1045 UTC. ...SPECIAL FEATURES... TROPICAL STORM INGRID IS CENTERED NEAR 15.1N 49.2W AT 14/0900 UTC OR ABOUT 700 NM EAST OF THE LESSER ANTILLES MOVING WEST-NORTHWEST AT 6 KT. ESTIMATED MINIMUM CENTRAL PRESSURE IS 1002 MB. MAXIMUM SUSTAINED WIND SPEED IS 35 KT WITH GUSTS TO 45 KT. SEE LATEST NHC FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMAT3/WTNT23 KNHC FOR MORE DETAILS. SATELLITE IMAGERY SHOWS A CIRCULAR MASS OF MODERATE TO STRONG CONVECTION FROM 13N-16N BETWEEN 48W-51W. THIS CONVECTIVE STRUCTURE IS BETTER ORGANIZED THAN LAST NIGHT WHEN IT APPEARED MORE ELONGATED N-S. THE LOW-LEVEL CENTER IS CHALLENGING TO PIN DOWN BUT IT APPEARS TO EMBEDDED UNDER THE DEEP CONVECTION. GIVEN THE MODERATE W TO SW SHEAR EFFECTING THE SYSTEM ONLY SLIGHT INTENSIFICATION IS FORECAST IN THE SHORT TERM. THEREAFTER GRADUALLY WEAKENING IS ANTICIPATED AS IT MOVES INTO A REGION OF STRONGER SHEAR. ...TROPICAL WAVES... TROPICAL WAVE IS TITLED THROUGH THE CAPE VERDE ISLANDS ALONG 18N22W 3N27W MOVING W 10-15 KT. A 1010 MB LOW IS ANALYZED ALONG THE WAVE AXIS NEAR 10N...CONFIRMED BY A BROAD AREA OF CYCLONIC TURNING IN AN EARLIER QSCAT PASS. OVERALL...THIS WAVE HAS CHANGED LITTLE OVER THE PAST 24 HOURS WITH CONVECTION LIMITED AND DISORGANIZED WITHIN 180 NM W OF THE WAVE AXIS. THE UW-CIMSS TPW ANIMATION SHOWS A WELL DEFINED WIDE MOISTURE PLUME ASSOCIATED WITH THIS WAVE...MAKING IT EASY TO TRACK. HIGH AMPLITUDE TROPICAL WAVE IS ALONG 40W/41W S OF 17N MOVING W 5 TO 10 KT. THE NRN PART OF THE WAVE HAS FRACTURED BASED ON THE POLEWARD MOVEMENT OF MOISTURE SEEN ON SATELLITE IMAGES AND THE UW CIMSS TPW ANIMATION. A SLOPING TROUGH WAS ANALYZED TO REFLECT THIS RUNNING FROM 19N40W TO 30N38W. THIS WAVE BREAK IS BEING INDUCED BY A DEEP LAYER TROUGH ASSOCIATED WITH A LOW PRES SYSTEM WELL N OF THE REGION. THE NRN PART...TROUGH...CURRENTLY LIES IN AN UPPER DIFFLUENT ZONE WHICH HAS FUELED SCATTERED MODERATE CONVECTION WITHIN 240 NM E OF THE ANALYZED AXIS...DUE TO STRONG SWLY SHEAR. THE SRN PORTION OF THE WAVE IS MUCH LESS DEFINED THAN PREVIOUS DAYS BUT IS MAINTAINING SCATTERED MODERATE CONVECTION WITHIN 60 NM OF THE AXIS FROM 4N-8N. TROPICAL WAVE HAS BEEN ADDED TO THE 06Z ANALYSIS ACROSS THE LESSER ANTILLES TITLED ALONG 19N58W 7N62W ESTIMATED TO BE MOVING W 10-15 KT. THERE WERE SEVERAL DATA SOURCES INDICATING THE EXISTENCE OF THIS WAVE. PROBABLY THE CLEAREST INDICATOR WAS THE MOISTURE PERTURBATION WHICH PULLED NWD OUT OF THE ITCZ A COUPLE OF DAYS AGO AND HAS BEEN TRACKING WNW. SOUNDING DATA FROM TRINIDAD IS ALSO CONVINCING SHOWING A WAVE PASSAGE BEFORE 00Z. THIRDLY...PRESSURE TENDENCIES ACROSS THE E CARIB ISLANDS ARE RUNNING 1-2 MB LOWER THAN THIS TIME YESTERDAY...WHICH IS TYPICAL FOR A WEAK TO MODERATE WAVE. I SPECULATE THAT THIS WAVE MAY BE THE SAME ONE THAT SPAWNED INGRID...BUT DATA SUPPORTING THAT IS NOT CONCLUSIVE. AN AREA OF CLOUDINESS AND SCATTERED SHOWERS ARE AFFECTING THE WINDWARD ISLANDS S OF 14N WITHIN 90 NM OF THE WAVE AXIS. TROPICAL WAVE IS HAS BEEN ADJUSTED AHEAD SLIGHTLY IN THE W CARIBBEAN ALONG 87W S OF 22N MOVING W 15-20 KT. THE NARROW MOISTURE SWATH...USED TO TRACK THIS WAVE ON THE TPW ANIMATION OVER THE PAST FEW DAYS...HAS BECOME MORE COMPLEX DUE TO THE UPPER FEATURES AFFECTING THE MOISTURE PATTERN. HOWEVER...IT STILL SUGGESTS A FASTER FORWARD SPEED THAN PREVIOUSLY THOUGHT. THE INTERACTION BETWEEN THIS WAVE...THE ITCZ...AND DIFFLUENCE ALOFT...IS MAINTAINING CLUSTERS OF SCATTERED MODERATE CONVECTION ACROSS THE SW CARIB ROUGHLY S OF 15N W OF 75W. ...THE ITCZ... ITCZ AXIS IS CENTERED ALONG 14N17W 8N29W 7N39W 11N48W 10N62W. BESIDES FOR THE CONVECTION ASSOCIATED WITH THE TROPICAL WAVES AND RECENTLY UPGRADED T.S. INGRID...NO SIGNIFICANT CONVECTION. DISCUSSION... THE GULF OF MEXICO... THE WEATHER ACROSS THE NRN GULF IS FAIRLY QUIET THIS MORNING WITH WHATS LEFT OF HUMBERTO WELL INLAND AND WEAKENING. THE MOISTURE PATTERN IN THE REGION IS GOVERNED BY UPPER LEVEL FEATURES. THE PREDOMINANT SYSTEM IS AN NE-SW ELONGATED UPPER HIGH CENTERED OVER N FLA. A FAIR AMOUNT OF CLOUDINESS AND ISOLATED SHOWERS ARE LOCKED WITHIN THE RIDGE...ROUGHLY N OF 25N. A WEDGE OF DRY AIR IS EVIDENT ON WATER VAPOR IMAGERY BETWEEN 22N-25N DUE TO A SLIGHTLY CONFLUENT PATTERN BETWEEN THE RIDGE AND TROUGHING TO THE S AND E. MOISTURE INCREASES AGAIN IN THE BAY OF CAMPECHE NEAR THE PROXIMITY OF THE TROUGHING. A SMALL AREA OF MODERATE CONVECTION IS S OF 20N W OF 95W. SFC WINDS ARE MOSTLY LIGHT FROM THE S TO SE...EXCEPT W TO SWLY BEHIND HUMBERTO'S TRAILING TROUGH IN THE FAR NW CORNER OF THE GULF. THE CARIBBEAN SEA... CLUSTERS OF SCATTERED MODERATE CONVECTION HAVE PERSISTED OVERNIGHT ACROSS THE SW CARIB ROUGHLY S OF 15N W OF 75W. THE CONTRIBUTING LOW-LEVEL SYSTEMS INCLUDE A WEAK TROPICAL WAVE ALONG 87W AND THE ITCZ WHICH BASED ON QSCAT DATA APPEARS TO RUN ALONG 10N-11N. CONVERGENCE ALONG THESE BOUNDARIES COUPLED WITH INSTABILITY AND DIFFLUENCE ALOFT ARE THE MAIN LIFTING MECHANISMS. FAIRLY STRONG UPPER WLY FLOW...VERY UNFAVORABLE FOR TROPICAL CYCLONES...HAS SET UP ABOVE THE MAJORITY OF THE CARIB BETWEEN AN UPPER HIGH OVER COLOMBIA AND UPPER TROUGHING OVER CUBA AND AN UPPER LOW N OF THE ERN CARIB. THIS FLOW IS TRANSPORTING DEBRIS HIGH LEVEL CLOUDINESS ACROSS THE AREA CONTAINED S OF 20N W OF 75W. THE AIR GREATLY DRIES OUT E OF 75W...THOUGH THERE ARE A COUPLE OF EXCEPTIONS. INSTABILITY ASSOCIATED WITH THE UPPER LOW MENTIONED HAS MOISTENED THE ENVIRONMENT HELPING TO PRODUCE TRADE WIND SCATTERED SHOWERS ACROSS PUERTO RICO AND THE VIRGIN ISLANDS. SIMILAR WEATHER IS LIKELY OVER THE SRN WINDWARD ISLANDS ASSOCIATED WITH A TROPICAL WAVE. THE ATLANTIC OCEAN... TROPICAL STORM INGRID IS THE MAIN FEATURE OF INTEREST ACROSS THE TROPICAL AND SUBTROPICAL ATLC DISCUSSION ZONE. FOR DETAILS AND REFERENCES REFER TO THE SPECIAL FEATURE SECTION ABOVE. ONE OTHER AREA OF ACTIVE WEATHER IS IN THE CENTRAL ATLC ASSOCIATED WITH THE NRN EXTENSION OF A TROPICAL WAVE. FOR DETAILS SEE ABOVE. THE REMAINDER OF THE SFC PATTERN IS DOMINATED BY TYPICAL SUBTROPICAL RIDGING. THERE REMAINS A FAIRLY PRONOUNCED WEAKNESS IN THIS RIDGE BETWEEN 35W-45W INDUCED BY A PERSISTENT BUT WEAKENING AREA OF LOW PRES WELL N OF THE AREA. ALOFT...A COMPLEX PATTERN REMAINS IN PLACE ACROSS THE CENTRAL AND W ATLC. THE LARGE SCALE FEATURES CONSIST OF THE ERN PERIPHERY OF A HIGH CENTERED OVER N FLA...ANOTHER UPPER HIGH LOCATED NE OF BERMUDA NEAR 35N51W...AN UPPER LOW S OF BERMUDA NEAR 26N66W AND ANOTHER UPPER LOW CENTERED NEAR 25N52W. THE ONLY SYSTEM CURRENTLY PRODUCING ANY SENSIBLE WEATHER IS THE UPPER LOW S OF BERMUDA...WHICH HAS A RELATED LOW-LEVEL TROUGH...PRODUCING SCATTERED SHOWERS FROM 22N-26N BETWEEN 60W-68W. FARTHER E...THE PERSISTENT DEEP LAYER TROUGH MENTIONED ABOVE COMBINED WITH VERY LARGE UPPER LOW OVER SRN SPAIN HAS CREATED QUITE A BIT OF TROUGHING ACROSS THE N PART OF THE E ATLC DISCUSSION AREA. THE TROPICAL E AND CENTRAL ATLC IS STILL DOMINATED BY A E-W RIDGE COVERING THE AREA FROM THE LESSER ANTILLES EWD WITH A MEAN AXIS ALONG 15N WITH SEVERAL EMBEDDED ANTICYCLONES. $$ CANGIALOSI