000 AXNT20 KNHC 081040 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 805 AM EDT MON OCT 08 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 1030 UTC. ...SPECIAL FEATURE... A BROAD AREA OF LOW PRES IS CENTERED IN THE NW CARIB NEAR 18.5N85W...ANALYZED 1003 MB AT 09Z. THIS LOW SITS ALONG A SFC TROUGH WHICH RUNS ENE FROM THE LOW TOWARD CUBA NEAR 20N79W AND WNW OF THE LOW ACROSS THE YUCATAN PENINSULA AND INTO THE SW GULF. SYNOPTIC 24-HOUR PRESSURE TENDENCIES ONLY INDICATE SLIGHT DEEPENING SINCE YESTERDAY AT THIS TIME. SATELLITE IMAGES CONTINUE TO SHOW A RATHER BROAD AREA OF LOW TO MID LEVEL TURNING. A 0230Z ASCAT OVERPASS CONFIRMED THE SATELLITE APPEARANCE REVEALING AN ELONGATED CIRCULATION WITH LIGHT WINDS. CONVECTION HAS INCREASED SOME OVERNIGHT...BUT STILL REMAINS STRETCHED OUT ALONG THE TROUGH AXIS FROM 17N-19N BETWEEN 84W-88W. UPPER-LEVEL WINDS ARE FAVORABLE FOR DEVELOPMENT OF THIS SYSTEM DURING THE NEXT COUPLE OF DAYS AS IT MOVES VERY SLOWLY WESTWARD OR NORTHWESTWARD. AN AIR FORCE HURRICANE HUNTER AIRCRAFT IS SCHEDULED TO INVESTIGATE THIS SYSTEM LATER TODAY...IF NECESSARY. ...TROPICAL WAVES... TROPICAL WAVE IS ALONG 38W/39W S OF 13N ESTIMATED TO BE MOVING W 15 KT. THIS LOW AMPLITUDE WAVE HAS BEEN DIFFICULT TO SEE SINCE EMERGING OFF THE AFRICAN COAST...LIKELY A FEW DAYS AGO...AS IT HAS BEEN EMBEDDED WITHIN THE LINEAR ITCZ CLOUDINESS. THE WAVE IS MORE VISIBLE ON THIS MORNING'S IMAGERY WITH THE ASSOCIATED DEEP CLOUDINESS REACHING A POLEWARD CREST ALONG THE ANALYZED AXIS. THE MIMIC TPW ANIMATION SHOWS A NARROW RATHER QUICK WWD MOVING MOISTURE BUMP PERTURBING THE ITCZ...RELATED TO THIS WEAK FEATURE. SCATTERED SHOWERS AND TSTMS ARE WITHIN 210 NM EITHER SIDE OF THE AXIS. TROPICAL WAVE IS ALONG 56W S OF 20N MOVING W TO NW NEAR 10 KT. A 1010 MB LOW IS LOCATED ALONG THE WAVE AXIS NEAR 18N. THIS LOW ONLY CONSISTS OF LOW-LEVEL CLOUDS...AND IN FACT MAY BE OPENING UP. WEAKENING SCATTERED MODERATE CONVECTION IS WELL REMOVED TO THE E OF THE WAVE FROM 16N-18N BETWEEN 51W-53W...SHEARED OFF BY STRONG UPPER SWLY FLOW. ...THE ITCZ... ITCZ AXIS IS CENTERED ALONG 12N16W 7N29W 9N37W 8N43W 10N62W. THE AXIS REMAINS ACTIVE TONIGHT. IN ADDITION TO THE CONVECTION ASSOCIATED WITH THE TROPICAL WAVES...SCATTERED MODERATE IS WITHIN 180 NM N AND 210 NM S OF THE AXIS BETWEEN 24W-50W. SIMILAR CONVECTION IS FROM 4N-6N E OF 19W. DISCUSSION... THE GULF OF MEXICO... QUITE BREEZY WEATHER CONTINUES OVER THE CENTRAL AND EASTERN GULF WATERS THIS MORNING. DATA FROM SHIPS...BUOYS AND A RECENT ASCAT PASS REVEAL ELY WINDS MAINLY IN THE 15-20 KT RANGE E OF A SFC TROUGH AXIS ALONG 20N90W 26N95W. THIS MODERATE TO FRESH FLOW IS ASSOCIATED WITH A TIGHTENED PATTERN BETWEEN A BROAD LOW PRES AREA IN THE NW CARIB AND A HIGH PRES RIDGE PARKED OVER THE MID-ATLANTIC STATES. THIS STIFF FLOW IS PICKING UP STREAMS OF SHALLOW QUICK MOVING SHOWERS FROM THE ATLC AND STEERING THEM ACROSS FLA AND THE GULF WATERS. SLIGHTLY DEEPER MOISTURE IS IN PLACE ACROSS THE CENTRAL GULF...ROUGHLY S OF 27N BETWEEN 85W-93W...ASSOCIATED WITH DEEP LAYER INVERTED TROUGHING RELATED TO THE NW CARIB LOW. CURRENTLY...IR IMAGES ARE NOT INDICATING MUCH IN THE WAY OF ORGANIZED TSTM ACTIVITY EXCEPT FOR A SMALL PATCH FROM 24N-26N BETWEEN 86W-88W. THE WEATHER ACROSS THE FAR W/SW CORNER REMAINS TRANQUIL...SITUATED TO THE W OF THE INVERTED TROUGHING...WITH FAIR TO MOSTLY CLEAR SKIES AND RATHER LIGHT SFC FLOW . THE CARIBBEAN SEA... THE SLOW MOVING BROAD AREA OF LOW PRES IN THE NW CARIB BETWEEN BELIZE... HONDURAS...AND THE CAYMAN ISLANDS IS THE MAIN FEATURE OF INTEREST THIS MORNING. FOR DETAILS REFER TO THE SPECIAL FEATURE SECTION ABOVE. ELSEWHERE...SCATTERED MODERATE CONVECTION HAS MOVED LITTLE OVER THE PAST SEVERAL HOURS N OF 15N BETWEEN 74W-78W...WHICH INCLUDES PORTIONS OF JAMAICA...ERN CUBA AND THE WINDWARD PASSAGE. THIS ACTIVITY IS ASSOCIATED WITH MOIST SLY LOW-LEVEL FLOW AND SOME CONVERGENCE IN THE LOW-LEVELS TO THE S OF AN ATLC SFC TROUGH. UPPER-LEVEL FLOW IS ALSO DIFFLUENT OVER THIS REGION BETWEEN TROUGHING OVER THE BAHAMAS AND RIDGING OVER THE CENTRAL CARIBBEAN. THIS UPPER PATTERN IS HELPING TO GENERATE AND SPREAD WIDESPREAD HIGH LEVEL CLOUDINESS ACROSS THE ENTIRE REGION. THE SFC TRADE WIND FLOW HAS BEEN GREATLY INTERRUPTED OVER THE PAST COUPLE OF DAYS ESP W OF 70W...DUE TO THE BROAD LOW PRES TROUGH. THIS IS EXPECTED TO CONTINUE TO BE THE CASE FOR A COUPLE MORE DAYS AS THE LOW MOVES VERY SLOWLY. E OF 70W...TRADES ARE FAIRLY LIGHT BUT THEY MAY INCREASE SLIGHTLY BY MID-WEEK AS THE SUBTROPICAL ATLC HIGH RIDGES FURTHER W. THE ATLANTIC OCEAN... AN ELONGATED SFC TROUGH PERSISTS ACROSS MUCH OF THE SW AND CENTRAL ATLC EXTENDING FROM THE SE BAHAMAS NEWARD ALONG 22N77W 23N60W 32N48W. A WEAK LOW...ANALYZED 1010 MB...HAS FORMED ALONG THE TROUGH AXIS NEAR 27N52W. A MID TO UPPER-LEVEL TROUGH WITH A SERIES OF EMBEDDED SHORTWAVES ARE SUPPORTING THIS LONG STRETCHED OUT SURFACE FEATURE. THERE ARE A COUPLE OF AREAS ALONG THE TROUGH WHERE LOW TO MID-LEVEL VORTICITY APPEARS TO BE MAXIMIZED. ONE IS LOCATED SEVERAL HUNDRED MILES NORTH OF PUERTO RICO ..WHERE THERE IS A CLUSTER OF SCATTERED MODERATE CONVECTION FROM 22N-25N BETWEEN 65W-68W. THE SECOND VORT MAX IS STRONGLY SHEARED LOCATED TO THE E OF THE WEAK SFC LOW GENERATING SCATTERED MODERATE CONVECTION FROM 24N-29N BETWEEN 45W-51W. UPPER-LEVEL WINDS REMAIN STRONG WHICH ARE INHIBITING ANY TROPICAL DEVELOPMENT OF THESE SYSTEMS. N AND W OF THE TROUGH AXIS...ELY SFC WINDS REMAIN MODERATE TO FRESH DUE TO THE TIGHTENED GRADIENT BETWEEN THE TROUGH AND HIGH PRES OVER THE MID ATLC STATES. MUCH QUIETER WEATHER EXISTS E OF 40W UNDER THE INFLUENCE OF A SFC RIDGE EXTENDING SW FROM A 1027 MB HIGH E OF THE AZORES NEAR 39N17W. THIS IS KEEPING WINDS LIGHT IN THE SUBTROPICS AND MODERATE IN THE TROPICS...EXCEPT SLIGHTLY STRONGER 20-25 KT NLY WINDS OFF THE COAST OF NW AFRICA WHERE THE GRADIENT REMAINS TIGHTER PER USUAL. THE MAIN MID TO UPPER LEVEL FEATURE OVER THE TROPICS IS AN UPPER HIGH LOCATED NEAR 12N39W. THE UPPER-LEVEL FLOW IS QUITE STRONG OUT OF THE W TO SW ON THE NORTHERN SIDE OF THE TROPICAL RIDGE WHICH IS SPREADING SOME HIGH DEBRIS CLOUDINESS...FROM ITCZ CONVECTION...S OF 20N BETWEEN 30W-45W. A SHARP UPPER TROUGH IS BEGINNING TO CUT OFF JUST TO THE NE OF THE MADEIRA ISLANDS. THIS FEATURE IS GENERATING SOME CLOUDINESS AND SHOWERS OVER THOSE ISLANDS AND NE TOWARD SRN PORTUGAL WITH A TAIL OF MOISTURE PASSING THROUGH THE CANARY ISLANDS. $$ CANGIALOSI