000 AXNT20 KNHC 220516 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 105 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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 0445 UTC. ...TROPICAL WAVES... TROPICAL WAVE IS TILTED FROM 14N56W TO 7N58W TO S GUYANA AT 7N58W. 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. SCATTERED SHOWERS ARE OCCURRING WITHIN 120 NM EITHER SIDE OF THE WAVE AXIS N OF 9N. ...THE ITCZ... THE ITCZ AXIS IS ANALYZED ALONG 12N15W 10N22W 8N32W 7N42W 4N52W. SCATTERED MODERATE CONVECTION IS FROM 5N-8N BETWEEN 18W-29W. ...DISCUSSION... GULF OF MEXICO... STRONG SW TO W UPPER LEVEL WINDS COVER THE GULF REGION IN THE BASE OF A BROAD UPPER TROUGH OVER THE E CONUS AND W ATLC. THIS UPPER TROUGH IS SUPPORTING A SURFACE FRONT THAT EXTENDS FROM S FLORIDA NEAR 25N81W TO 25N89W TO A 1025 MB SURFACE LOW IN THE W GULF NEAR 25N96W TO 21N97W AND EXTENDS WESTWARD OVER E MEXICO. ALSO...A SURFACE TROUGH EXTENDS NORTHWARD FROM THE SURFACE LOW TO 27N97W TO SE OF THE TEXAS COAST NEAR 28N96W. LOW LEVEL CONVERGENCE IS SUPPORTING SCATTERED SHOWERS WITHIN 60 NM OF THE SURFACE FRONT...LOW...AND 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 1038 MB SURFACE HIGH OVER THE E CONUS...WITH AN ASSOCIATED SURFACE RIDGE EXTENDING ACROSS THE N GULF. FREEZE WARNINGS AND WIND CHILL ADVISORIES ARE IN EFFECT FOR TONIGHT THROUGH SATURDAY MORNING FOR PORTIONS OF FLORIDA. 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 FROM 25N-28N. 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 STATIONARY FRONT EXTENDS FROM THIS SURFACE LOW TO 16N76W TO E HISPANIOLA NEAR 19N68W. LOW LEVEL CONVERGENCE NEAR THE SURFACE LOW AND SURFACE 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 DIVERGENCE IN THE VICINITY OF AN UPPER RIDGE PRESENT OVER THE W CARIBBEAN...WITH THE AXIS OF THIS UPPER RIDGE EXTENDING FROM N COLOMBIA NEAR 11N73W TO 17N81W TO THE NW CARIBBEAN NEAR 21N85W. OVER THE E CARIBBEAN...UPPER LEVEL DIVERGENCE IS INTERACTING WITH DEEP LAYER MOISTURE TO SUPPORT SCATTERED SHOWERS AND THUNDERSTORMS S OF 15N E OF 69W. ATLANTIC OCEAN... A BROAD UPPER LEVEL TROUGH OVER THE E CONUS AND W ATLC IS SUPPORTING A SURFACE COLD FRONT THAT EXTENDS FROM S FLORIDA NEAR 25N81W TO 29N73W TO 32N69W TO NE 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 79W. ALSO...A SURFACE STATIONARY FRONT EXTENDS FROM E HISPANIOLA NEAR 19N68W TO 25N58W TO 32N50W...WITH SCATTERED SHOWERS WITHIN 60 NM EITHER SIDE OF THE STATIONARY FRONT. OVER THE NEXT DAY...A 1017 MB SURFACE LOW IS FORECAST TO FORM NEAR 28N55W. TO THE E...A SURFACE TROUGH EXTENDS FROM 28N50W TO 22N44W...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 43W WITH AN ASSOCIATED SURFACE TROUGH EXTENDING FROM A 1014 MB SURFACE LOW NEAR 23N32W TO 20N32W TO 18N34W. LOW LEVEL CONVERGENCE NEAR THE SURFACE TROUGH AND SURFACE LOW IS SUPPORTING SCATTERED SHOWERS FROM 18N-25N BETWEEN 25W-33W...WHICH IS BEING ENHANCED BY UPPER LEVEL DIVERGENCE ASSOCIATED WITH A MID/UPPER-LEVEL WIND SPEED MAXIMUM. $$ COHEN