AXNT20 KNHC 221141 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 705 AM EST SAT NOV 22 2008 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 1115 UTC. ...TROPICAL WAVES... TROPICAL WAVE IS TILTED FROM 14N57W TO 8N59W ACROSS GUYANA TO 3N60W. THIS WAVE IS MOVING W NEAR 10 KT. CIMSS WAVETRAK PRODUCT INDICATES A MAXIMUM IN LOW LEVEL CYCLONIC CIRCULATION IN THE VICINITY OF THIS WAVE. ADDITIONALLY...A MAXIMUM IN DEEP LAYER MOISTURE COINCIDES WITH THIS WAVE BASED ON TOTAL PRECIPITABLE WATER PRODUCT FROM CIMSS. UPPER AIR TIME-HEIGHT ANALYSIS SUGGESTS THAT THIS WAVE HAS NOT YET CROSSED BARBADOS NEAR 13N60W...WHERE PERSISTENT NORTHEASTERLY LOW LEVEL FLOW PREVAILS. SCATTERED SHOWERS ARE OCCURRING WITHIN 150 NM EITHER SIDE OF THE WAVE AXIS N OF 10N. ...THE ITCZ... THE ITCZ AXIS IS ANALYZED ALONG 9N13W 8N22W 8N32W 7N42W 5N54W. SCATTERED MODERATE CONVECTION IS FROM 5N-10N BETWEEN 13W-25W. SIMILAR CONVECTION IS FROM 5N-9N BETWEEN 18W-31W. ...DISCUSSION... GULF OF MEXICO... STRONG SW TO W UPPER LEVEL WINDS...IN THE BASE OF A BROAD UPPER TROUGH OVER THE E CONUS AND W ATLC...COVER THE GULF REGION. THIS UPPER TROUGH IS SUPPORTING A SURFACE COLD FRONT THAT EXTENDS FROM NW OF CUBA NEAR 24N81W TO 23N93W TO THE BAY OF CAMPECHE NEAR 19N95W AND EXTENDS TO THE NORTHWEST OVER MEXICO. THIS COLD FRONT IS WEAKENING W OF 88W. ALSO...A SURFACE TROUGH...LOCATED N OF THE COLD FRONT...EXTENDS FROM 26N96W TO 23N95W. LOW LEVEL CONVERGENCE IS SUPPORTING SCATTERED SHOWERS WITHIN 60 NM OF THE SURFACE FRONT AND SURFACE TROUGH. TO THE N OF THESE FEATURES...A COOLER AND DRIER AIRMASS...CHARACTERIZED AS A MODIFIED CONTINENTAL POLAR AIRMASS...IS IN PLACE. THIS AIRMASS IS BEING SUPPORTED BY A 1037 MB SURFACE HIGH OVER THE E CONUS...WITH AN ASSOCIATED SURFACE RIDGE EXTENDING ACROSS THE N GULF. AS COOLER AIR IS BEING ADVECTED OVER THE RELATIVELY WARMER GULF WATERS... WEAK LOW LEVEL INSTABILITY IS SUPPORTING SCATTERED STRATOCUMULUS CLOUDS ACROSS THE GULF MAINLY N OF 24N W OF 85W. HOWEVER... SUBSIDENCE AND STABLE ATMOSPHERIC CONDITIONS HIGHER IN THE ATMOSPHERE ARE INHIBITING DEEP CONVECTION ACROSS THE GULF REGION. ADDITIONALLY...STRONG N TO NE SURFACE WINDS ARE BLOWING THROUGH THE ISTHMUS OF TEHUANTEPEC RESULTING IN GALE FORCE WINDS IN THE E PACIFIC REGION. CARIBBEAN SEA... IN THE SW CARIBBEAN...A 1009 MB SURFACE LOW IS LOCATED N OF PANAMA NEAR 10N82W. ADDITIONALLY...A SURFACE TROUGH EXTENDS FROM THIS SURFACE LOW TO 14N77W TO 15N71W...WITH A WEAKENING SURFACE STATIONARY FRONT EXTENDING FROM 15N71W TO E OF HISPANIOLA NEAR 18N68W. LOW LEVEL CONVERGENCE NEAR THE SURFACE LOW...TROUGH... AND FRONT IS INTERACTING WITH DEEP LAYER MOISTURE OVER THE S CARIBBEAN TO GENERATE SCATTERED SHOWERS AND THUNDERSTORMS OVER THE CARIBBEAN S OF 15N W OF 76W. THIS ACTIVITY IS BEING ENHANCED BY UPPER LEVEL DIFFLUENCE IN THE VICINITY OF AN UPPER RIDGE PRESENT OVER THE W CARIBBEAN...WITH THE AXIS OF THIS UPPER RIDGE EXTENDING FROM N COLOMBIA NEAR 12N72W TO 16N79W TO THE NW CARIBBEAN NEAR 20N85W. OVER THE E CARIBBEAN...UPPER LEVEL DIVERGENCE IS INTERACTING WITH DEEP LAYER MOISTURE TO SUPPORT SCATTERED SHOWERS AND THUNDERSTORMS S OF 16N E OF 71W. ATLANTIC OCEAN... A BROAD UPPER LEVEL TROUGH OVER THE E CONUS AND W ATLC IS SUPPORTING A SURFACE COLD FRONT THAT EXTENDS FROM NW OF CUBA NEAR 24N81W TO 28N68W TO 32N65W TO N OF THE DISCUSSION AREA. ISOLATED SHOWERS ARE OCCURRING WITHIN 60 NM EITHER SIDE OF THIS COLD FRONT. TO THE W OF THIS COLD FRONT...A MODIFIED CONTINENTAL POLAR AIRMASS IS IN PLACE...WITH TEMPERATURES BELOW SEASONAL AVERAGES ACROSS FLORIDA AND SCATTERED STRATOCUMULUS CLOUDS BETWEEN THIS FRONT AND THE COAST OF THE SE CONUS. ALSO...A WEAKENING SURFACE STATIONARY FRONT EXTENDS FROM E OF HISPANIOLA NEAR 18N68W TO 25N58W TO 31N51W...WITH SCATTERED SHOWERS WITHIN 60 NM EITHER SIDE OF THIS STATIONARY FRONT. TO THE E...A SURFACE TROUGH EXTENDS FROM 27N51W TO 22N47W...WITH ANOTHER SURFACE TROUGH EXTENDING FROM 16N55W TO 14N49W. ISOLATED SHOWERS ARE OCCURRING WITHIN 60 NM EITHER SIDE OF EACH OF THESE SURFACE TROUGHS. ALSO...AN UPPER TROUGH IS PRESENT OVER THE E ATLC N OF 20N E OF 42W WITH AN ASSOCIATED SURFACE TROUGH EXTENDING FROM A 1014 MB SURFACE LOW NEAR 23N32W TO 22N29W TO 17N31W. LOW LEVEL CONVERGENCE NEAR THE SURFACE TROUGH AND SURFACE LOW IS SUPPORTING SCATTERED SHOWERS FROM 19N-24N BETWEEN 25W-34W...WHICH IS BEING ENHANCED BY UPPER LEVEL DIVERGENCE IN THE VICINITY OF A MID/UPPER-LEVEL WIND SPEED MAXIMUM. $$ COHEN
