000 AXNT20 KNHC 131750 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 205 PM EDT TUE OCT 13 2009 TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL AMERICA...GULF OF MEXICO...CARIBBEAN SEA...NORTHERN SECTIONS OF SOUTH AMERICA...AND 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 1715 UTC. ...TROPICAL WAVES... TROPICAL WAVE EXTENDS FROM 14N54W TO 8N56W MOVING W NEAR 15 KT. THE WAVE IS REPOSITIONED FARTHER W AFTER FURTHER ANALYSIS OF CURRENT VISIBLE IMAGERY AS WELL AS A 3-5 DAY LOOP OF IMAGERY. OVER THE PAST FEW DAYS...THE WAVE HAS PROGRESSED THROUGH A SHEARED ENVIRONMENT AS MIDDLE TO UPPER LEVEL TROUGHING HAS PERSISTED ACROSS PORTIONS OF THE ERN AND CENTRAL ATLC. THIS HAS DE-AMPLIFIED THE WAVE GRADUALLY WITH TIME AND A LOWER AMPLITUDE WAVE REMAINS PROPAGATING WWD S OF 14N. THE NEW POSITION OF THE WAVE MATCHES UP WELL WITH A MAXIMUM IN TOTAL PRECIPITABLE WATER AS WELL AS LOW-LEVEL 850 MB RELATIVE VORTICITY MODEL GUIDANCE IN THE VICINITY OF THE WAVE. AS THE WAVE CURRENTLY INTERACTS WITH AN UPPER LEVEL LOW CENTERED NEAR 15N55W...SCATTERED MODERATE CONVECTION IS FROM 8N-14N BETWEEN 52W-59W. ...ITCZ... THE ITCZ AXIS IS CENTERED ALONG 10N14W 7N27W 9N41W. A SURFACE TROUGH IS EMBEDDED WITHIN THE ITCZ AND ANALYZED FROM 13N42W TO 6N45W. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS FROM 6N-10N BETWEEN 43W-53W MOSTLY TO THE W OF THE SURFACE TROUGH. CLUSTERS OF SCATTERED MODERATE CONVECTION ARE FROM 4N-11N BETWEEN 19W-31W. ...DISCUSSION... GULF OF MEXICO... A STATIONARY FRONT IS ACROSS THE NE GULF COAST EXTENDING FROM THE FLORIDA BIG BEND REGION ALONG 30N TO INLAND OVER LOUISIANA NEAR NEW ORLEANS. A FEW ISOLATED SHOWERS ARE WITHIN 30 NM OF THE FRONT BETWEEN 86W-89W. FARTHER TO THE W...A DEVELOPING AREA OF LOW PRESSURE IS ACROSS NE TEXAS WITH SOUTHERLY RETURN FLOW FEEDING INTO A 1015 MB LOW CENTERED NEAR 32N96W. LOW-LEVEL CONVERGENCE ACROSS THE NW GULF AND INLAND ACROSS COASTAL TEXAS IS GENERATING SCATTERED SHOWERS AND ISOLATED TSTMS NW OF A LINE FROM 29N91W TO 25N98W. THIS ACTIVITY IS LOCATED ON THE NW PERIPHERY OF A BROAD UPPER RIDGE CENTERED IN THE CENTRAL GULF NEAR 26N89W THAT CONTINUES TO EXTEND AN UPPER LEVEL RIDGE AXIS ALONG 26N E OF 103W TO OVER THE SRN FLORIDA PENINSULA AND INTO THE W ATLC. THE REMAINDER OF THE GULF IS UNDER GENERALLY CLEAR SKIES AND FAIR WEATHER AS A SURFACE RIDGE EXTENDS S OF THE STATIONARY FRONT IN THE NE GULF THROUGH 25N90W TO 20N97W. CARIBBEAN SEA... A BROAD UPPER RIDGE THAT COVERS THE W ATLC AND GULF OF MEXICO IS PROVIDING THE CARIBBEAN BASIN WITH E-NE UPPER LEVEL WINDS. WATER VAPOR IMAGERY INDICATES A VERY DRY AND STABLE AIRMASS OVER MUCH OF THE BASIN INCLUDING THE GREATER AND LESSER ANTILLES. FRESH TO MODERATE TRADE WINDS CONTINUE WITH ISOLATED LOW-LEVEL SHOWERS MOVING ACROSS THE NRN PORTION OF THE BASIN N OF 15N. MORE WIDELY SCATTERED ACTIVITY HOWEVER IS FOUND ACROSS THE NW CARIBBEAN AS LOW-LEVEL SPEED CONVERGENCE IS GENERATING SHOWERS AND TSTMS COVERING THE AREA FROM 16N-21N BETWEEN 83W-88W. ELSEWHERE...THE ITCZ EXTENDS ALONG 9N ACROSS PANAMA AND THE EXTREME SW WATERS. SCATTERED SHOWERS AND ISOLATED TSTMS ARE OCCURRING S OF 11N BETWEEN 76W-83W. ATLANTIC OCEAN... AN UPPER LEVEL SHORTWAVE TROUGH IS EMBEDDED WITHIN W-NW FLOW ALOFT ACROSS THE W ATLC NEAR 36N70W SUPPORTS A 1013 MB LOW CENTERED NORTH OF THE DISCUSSION AREA NEAR 34N72W. A COLD FRONT EXTENDS FROM THE LOW ALONG 32N75W TO THE FLORIDA ATLC COAST NEAR ST. AUGUSTINE AND CONTINUES INTO THE GULF OF MEXICO AS A STATIONARY FRONT. SCATTERED SHOWERS AND ISOLATED TSTMS ARE WITHIN 150 NM S OF THE FRONT. AN UPPER LEVEL DIFFLUENT PATTERN IS IN PLACE E OF THE UPPER LEVEL SHORTWAVE TROUGH AXIS BETWEEN 50W-70W THAT IS GENERATING POSSIBLE SCATTERED SHOWERS N OF 28N BETWEEN 55W-70W. ACROSS THE ERN ATLC...AN UPPER LEVEL TROUGH DIGS S TO 12N E OF 40W. AN EMBEDDED SHORTWAVE TROUGH AXIS IS ALONG 34W AND SUPPORTS A 1012 MB LOW CENTERED NEAR 32N35W THAT EXTENDS A SURFACE TROUGH ALONG 30N33W 26N40W TO 25N46W. SCATTERED SHOWERS ARE OCCURRING WITHIN 60 NM EITHER SIDE OF THE SURFACE TROUGH WITH MORE WIDESPREAD SHOWER ACTIVITY LOCATED NE OF THE LOW FROM 30N TO BEYOND 32N BETWEEN 28W-36W. THE UPPER TROUGHING ALSO SUPPORTS A DISSIPATING STATIONARY FRONT THAT ENTERS OF THE DISCUSSION AREA NEAR 32N23W AND EXTENDS SW TO 25N33W. THIS FRONT CONTINUES TO PRODUCE SCATTERED SHOWERS WITHIN 90 NM EITHER SIDE OF THE BOUNDARY. A SURFACE TROUGH IS ANALYZED OVER THE TROPICAL CENTRAL ATLC FROM 18N44W TO 14N48W. THIS WEAK SURFACE TROUGH IS LIKELY A PIECE OF SHEARED ENERGY FROM THE TROPICAL WAVE ALONG 56W AND EXHIBITS NO SHOWERS OR DEEP CONVECTION. $$ HUFFMAN