000 AXNT20 KNHC 221721 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 105 PM EST SUN NOV 22 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 1645 UTC. ...ITCZ... THE ITCZ AXIS IS CENTERED ALONG 7N9W 6N22W 3N35W 8N48W 11N53W 10N63W. ISOLATED MODERATE CONVECTION IS FROM 4N-7N BETWEEN 18W-25W. SIMILAR ACTIVITY IS FROM 2N-5N BETWEEN 26W-35W...AND FROM 6N-8N BETWEEN 40W-47W. A SURFACE TROUGH EXTENDS FROM 18N49W TO 9N51W. ISOLATED MODERATE CONVECTION IS TO THE E OF THE AXIS FROM 10N-18N BETWEEN 43W-49W. ...DISCUSSION... GULF OF MEXICO... AS OF 1500 UTC...A 1013 MB LOW IS LOCATED S OF THE FLORIDA PANHANDLE NEAR 30N86W. A WARM FRONT EXTENDS TO THE E ALONG 31N83W 31N81W. A COLD FRONT EXTENDS TO THE SE FROM THE LOW CENTER ALONG 28N85W TURNING S-SW ALONG 26N86W 24N89W BECOMING STATIONARY TO 21N93W. MOST OF THE SHOWER ACTIVITY LIES BETWEEN THESE TWO FRONTS. RADAR IMAGERY INDICATES SHOWERS/THUNDERSTORMS ALONG A SWATH FROM 26N84W ACROSS TAMPA INTO CENTRAL FLORIDA NEAR 27N81W. A SECOND SWATH OF STRONGER SHOWERS/THUNDERSTORMS EXTENDS FROM 28N84W INTO THE BIG BEND OF FLORIDA TO NEAR 30N82W. ISOLATED SHOWERS/THUNDERSTORMS ARE WITHIN 100 NM OF THE STATIONARY FRONT AND ELSEWHERE BETWEEN THE WARM FRONT AND STATIONARY FRONT AFFECTING MUCH OF FLORIDA. AN OCCLUDED FRONT EXTENDS W FROM THE LOW CENTER TO A SECOND 1013 MB LOW OVER ERN LOUISIANA NEAR 31N90W. A SURFACE TROUGH EXTENDS FROM THIS LOW ALONG 29N91W 27N95W. IN THE UPPER LEVELS...MOIST SWLY FLOW EXTENDS ACROSS MUCH OF THE GULF AROUND A BROAD UPPER LEVEL TROUGH OVER THE CENTRAL CONUS. AN UPPER LEVEL LOW IS EMBEDDED IN THE LONGWAVE TROUGH CENTERED OVER TENNESSEE SUPPORTING THE LOW PRESSURE AND FRONTAL SYSTEM. A SLOT OF DRY AIR EXTENDS OVER SE TEXAS AND THE NW GULF. EXPECT THE LOW PRESSURE SYSTEM TO MOVE NE AS THE FRONTAL SYSTEM MOVES E...AND BOTH ARE EXPECTED TO WEAKEN OVER THE NEXT 24 HRS. SHOWERS/THUNDERSTORMS ARE EXPECTED OVER THE ERN GULF OF MEXICO AS THE LOW/FRONTAL SYSTEM PUSHES E. CARIBBEAN SEA... SIGNIFICANT DRY AIR AND SUBSIDENCE IS ACROSS THE CARIBBEAN NOTED IN WATER VAPOR IMAGERY SUPPORTING FAIR WEATHER ACROSS MUCH OF THE BASIN. A FEW SHOWERS/THUNDERSTORMS ARE S OF HISPANIOLA FROM 17N-18N BETWEEN 70W-74W ASSOCIATED WITH A SURFACE TROUGH N OF HISPANIOLA IN THE ATLC. SCATTERED SHOWERS/THUNDERSTORMS ARE ALSO ACROSS THE SW CARIBBEAN S OF 12N BETWEEN 79W-85W. THIS ACTIVITY IS ENHANCED BY SURFACE CONVERGENCE NEAR THE E PACIFIC ITCZ...AS WELL AS DIFFLUENT FLOW ALOFT BETWEEN AN UPPER LEVEL TROUGH SW OF CENTRAL AMERICA AND A BROAD UPPER LEVEL RIDGE THAT COVERS THE CARIBBEAN. MODERATE TO FRESH TRADEWINDS ARE ACROSS MUCH OF THE BASIN WITH STRONGER WINDS IN THE ERN CARIBBEAN AND NEAR THE COAST OF COLOMBIA. EXPECT LITTLE CHANGE OVER THE NEXT 24 HRS. ATLANTIC OCEAN... ISOLATED SHOWERS EXTEND INTO THE FAR WRN ATLC FROM ACROSS FLORIDA N OF 27N W OF 75W ASSOCIATED WITH A WARM FRONT EXTENDING ACROSS NRN FLORIDA TO NEAR 30N80W. A WEAK 1014 MB SURFACE LOW IS NEAR 31N73W WITH A SURFACE TROUGH EXTENDING TO NEAR 29N76W. SHOWERS ARE POSSIBLE NEAR THE LOW CENTER. AN UPPER LEVEL RIDGE COVERS THE WRN ATLC KEEPING THE REMAINDER OF THE AREA UNDER FAIR CONDITIONS...EXCEPT FOR AN AREA OF SHOWERS/THUNDERSTORMS ACROSS THE SE BAHAMAS FROM 20N-22N BETWEEN 70W-73W. THIS ACTIVITY IS ENHANCED BY SURFACE CONVERGENCE NEAR A SURFACE TROUGH THAT EXTENDS ALONG 30N59W S TO 25N62W SW ALONG 23N67W TO NRN HISPANIOLA NEAR 20N73W. ISOLATED SHOWERS ARE ALSO WITHIN 200 NM E OF THE TROUGH AXIS N OF 25N. FARTHER E...A SURFACE TROUGH EXTENDS FROM 30N50W TO 25N48W. SCATTERED SHOWERS/THUNDERSTORMS ARE WITHIN 150 NM OF THE TROUGH AXIS. A SECOND SURFACE TROUGH EXTENDS FROM THE FAR ERN ATLC ALONG 31N11W 29N22W 27N33W 30N43W. ISOLATED SHOWERS ARE ALONG THE AXIS...AND N OF 21N BETWEEN 40W-45W. SCATTERED SHOWERS/THUNDERSTORMS ARE N OF THE TROUGH AXIS FROM 30N-33N BETWEEN 33W-40W. THIS SERIES OF TROUGHS AND ASSOCIATED SHOWER ACTIVITY IS SUPPORTED BY AN UPPER LEVEL TROUGH IN THE CENTRAL ATLC FROM 26N44W TO 12N51W. DIFFLUENT FLOW BETWEEN THIS TROUGH AND AN UPPER LEVEL RIDGE DIRECTLY TO THE N OF THE TROUGH IS ALSO ENHANCING THE SHOWER ACTIVITY. ZONAL WLY FLOW IS ACROSS THE TROPICAL ATLC. $$ WALTON