000 AXNT20 KNHC 140539 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 205 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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 0515 UTC. ...SPECIAL FEATURES... THE NINTH STORM OF THE YEAR...TROPICAL STORM INGRID...FORMS TO THE E OF THE LESSER ANTILLES. INGRID IS CENTERED NEAR 14.7N 48.7W AT 14/0300 UTC OR ABOUT 735 NM EAST OF THE LESSER ANTILLES MOVING WEST-NORTHWEST AT 5 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. NIGHT CHANNEL VIS IMAGES SHOW AN OVERALL SLIGHT IMPROVED STRUCTURE OF INGRID WITH THE LOW-LEVEL CENTER POSITIONED BETWEEN WEAK BANDS TO THE N AND W OF THE CENTER AND VERY NEAR THE PRIMARY CONVECTIVE AREA. HOWEVER...MODERATE WESTERLY SHEAR CONTINUES TO AFFECT THE CIRCULATION. IR IMAGERY SHOWS NUMEROUS MODERATE CONVECTION ...OVAL-LIKE SHAPED...FROM 13.5N-15.5N BETWEEN 48W-49W. GIVEN THE MODERATE SHEAR ENVIRONMENT ONLY SLIGHT INTENSIFICATION IS FORECAST IN THE SHORT TERM. THEREAFTER STEADY STATE OR WEAKENING IS LIKELY AS WESTERLY SHEAR INCREASES. ...TROPICAL WAVES... TROPICAL WAVE IS NEAR THE CAPE VERDE ISLANDS ALONG 23W S OF 18N 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 BECOME A LITTLE LESS DEFINED THAN 24 HOURS AGO WITH CONVECTION MINIMAL NEAR THIS FEATURE. THE UW-CIMSS TPW ANIMATION SHOWS A WELL DEFINED MOISTURE PLUME ASSOCIATED WITH THIS WAVE...MAKING IT EASY TO TRACK. HIGH AMPLITUDE TROPICAL WAVE IS ALONG 40W S OF 21N 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 22N40W TO 27N37W. THIS SPLIT 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 180 NM E OF THE ANALYZED AXIS. THE SRN PORTION OF THE WAVE IS MUCH LESS DEFINED THAN PREVIOUS DAYS WITH LITTLE SIGNIFICANT SHOWER ACTIVITY. TROPICAL WAVE IS IN THE W CARIBBEAN ALONG 82W S OF 22N MOVING W 15 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 APPEARS AS IF THIS WAVE COULD BE A LITTLE FURTHER W AND WILL REEVALUATE AT 06Z. 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 13N17W 9N29W 13N39W 11N54W 10N63W. BESIDES FOR THE CONVECTION ASSOCIATED WITH THE TROPICAL WAVES AND RECENTLY UPGRADED T.S. INGRID...SCATTERED MODERATE CONVECTION IS FROM 4N-8N BETWEEN 36W-42W. DISCUSSION... THE GULF OF MEXICO... THE WEATHER ACROSS THE NRN GULF HAS GREATLY CALMED DOWN AS HUMBERTO HAS TRACKED WELL INLAND AND WEAKENED TO A DEPRESSION. CURRENTLY...THE MOISTURE PATTERN IN THE REGION IS MAINLY GOVERNED BY UPPER LEVEL FEATURES. THE PREDOMINANT SYSTEM IS AN NE-SW ELONGATED UPPER HIGH CENTERED NEAR 28N90W. A FAIR AMOUNT OF CLOUDINESS AND ISOLATED SHOWERS ARE LOCKED WITHIN THE RIDGE...ROUGHLY N OF 26N. A WEDGE OF DRY AIR IS EVIDENT ON WATER VAPOR IMAGERY BETWEEN 24N-26N DUE TO A SLIGHTLY CONFLUENT PATTERN BETWEEN THE RIDGE AND TROUGHING TO THE S AND E. MOISTURE INCREASES AGAIN S OF 24N CLOSER TO THE PROXIMITY OF THE TROUGHING. THE ONLY AREA OF NOTABLE CONVECTION AT THE MOMENT IS IN THE BAY OF CAMPECHE E OF 94W ASSOCIATED WITH AN UPPER LOW OVER GUATEMALA. SFC WINDS ARE MOSTLY LIGHT OUT OF THE S TO SE...EXCEPT SWLY BEHIND THE TRAILING TROUGH ASSOCIATED WITH HUMBERTO. THE CARIBBEAN SEA... CLUSTERS OF SCATTERED MODERATE CONVECTION HAVE FIRED UP OVER THE SW CARIB THIS EARLY MORNING ROUGHLY S OF 15N W OF 75W. THE CONTRIBUTING LOW-LEVEL SYSTEMS INCLUDE A WEAK TROPICAL WAVE ALONG 82W 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 CONTRIBUTORS. FAIRLY STRONG UPPER WLY FLOW IS OBSERVED ACROSS THE MAJORITY OF THE CARIB SET UP BETWEEN AN UPPER HIGH OVER COLOMBIA AND UPPER TROUGHING OVER CUBA. THIS FLOW IS TRANSPORTING DEBRIS HIGH LEVEL CLOUDINESS ACROSS THE AREA CONTAINED W OF 75W. THE AIR GREATLY DRIES OUT E OF 75W...THOUGH THERE ARE A COUPLE OF EXCEPTIONS. INSTABILITY ASSOCIATED WITH DEEP LAYERED TROUGHING N OF THE ERN CARIB IS PRODUCING SCATTERED SHOWERS AND ISOLATED TSTMS ACROSS PUERTO RICO AND THE VIRGIN ISLANDS. SIMILAR WEATHER IS LIKELY OVER THE SRN WINDWARD ISLANDS ASSOCIATED WITH ITCZ ENERGY. THE ATLANTIC OCEAN... RECENTLY UPGRADED 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 GULF OF MEXICO HIGH...ANOTHER UPPER HIGH LOCATED NE OF BERMUDA NEAR 36N52W...AN UPPER LOW S OF BERMUDA NEAR 27N64W AND ANOTHER UPPER LOW CENTERED NEAR 25N50W. THE ONLY SYSTEM CURRENTLY PRODUCING ANY SENSIBLE WEATHER IS THE UPPER LOW S OF BERMUDA...WHICH APPEARS TO HAVE A RELATED LOW-LEVEL TROUGH...PRODUCING SCATTERED SHOWERS FROM 22N-26N BETWEEN 60W-67W. 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 AN E-W RIDGE COVERING THE AREA FROM THE LESSER ANTILLES EWD WITH A MEAN AXIS ALONG 17N WITH SEVERAL EMBEDDED ANTICYCLONES. $$ CANGIALOSI