000 AXNT20 KNHC 240513 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 105 AM EST MON NOV 24 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. ...SPECIAL FEATURE... IN THE SW CARIBBEAN...A 1007 MB SURFACE LOW IS CENTERED N OF PANAMA NEAR 10N80W. LOW LEVEL CONVERGENCE IN THE VICINITY OF THIS SURFACE LOW IS INTERACTING WITH DEEP LAYER MOISTURE OVER THE W CARIBBEAN TO RESULT IN NUMEROUS SHOWERS AND THUNDERSTORMS OVER THE CARIBBEAN S OF 15N W OF 77W...INCLUDING PORTIONS OF COSTA RICA...PANAMA...AND E NICARAGUA. THIS SHOWER AND THUNDERSTORM ACTIVITY HAS INCREASED AND BECOME BETTER ORGANIZED OVER THE LAST DAY...AND SOME ADDITIONAL DEVELOPMENT OF THIS SYSTEM IS POSSIBLE OVER THE NEXT COUPLE OF DAYS AS IT DRIFTS SLOWLY WESTWARD. REGARDLESS OF WHETHER OR NOT A TROPICAL CYCLONE FORMS...HEAVY RAINFALL AND LOCALIZED FLOODING WILL BE POSSIBLE OVER PORTIONS OF PANAMA...COSTA RICA...AND NICARAGUA DURING THE NEXT COUPLE OF DAYS. ...TROPICAL WAVES... TROPICAL WAVE IS OVER THE CENTRAL CARIBBEAN ALONG 74W S OF 17N MOVING W 10-15 KT. SATELLITE IMAGERY INDICATES CYCLONIC CIRCULATION COINCIDING WITH THIS WAVE. A MAXIMUM IN DEEP LAYER MOISTURE COINCIDES WITH THIS WAVE BASED ON TOTAL PRECIPITABLE WATER PRODUCT FROM CIMSS. ALSO...UPPER AIR TIME-HEIGHT ANALYSIS FOR CURACAO...LOCATED IN THE NETHERLANDS ANTILLES NEAR 12N69W...RECENTLY DEPICTS VEERING OF THE MEAN LOW/MID-LEVEL FLOW FROM NE TO SE...SUGGESTING THAT THIS WAVE HAS LIKELY MOVED W OF CURACAO. SCATTERED MODERATE CONVECTION IS OCCURRING WITHIN 150 NM EITHER SIDE OF THE WAVE AXIS S OF 16N. THIS WAVE IS BECOMING ABSORBED BY THE BROAD LOW LEVEL CYCLONIC CIRCULATION ASSOCIATED WITH THE 1007 MB SURFACE LOW NEAR 10N80W...WHICH IS DISCUSSED IN THE SPECIAL FEATURE SECTION ABOVE. ...THE ITCZ... THE ITCZ AXIS IS ANALYZED ALONG 9N12W 4N22W 6N33W 9N45W 6N58W. SCATTERED MODERATE IS FROM 5N-7N BETWEEN 18W-23W. SCATTERED MODERATE CONVECTION IS ALSO FROM 5N-8N BETWEEN 28W-31W. SIMILAR CONVECTION IS WITHIN 120 NM EITHER SIDE OF THE ITCZ AXIS BETWEEN 40W-49W. ...DISCUSSION... GULF OF MEXICO... STRONG SOUTHWESTERLY AND WESTERLY UPPER LEVEL WINDS COVER THE GULF REGION. AS A RESULT...UPPER LEVEL MOISTURE...ORIGINATING FROM THE E PACIFIC REGION...IS STREAMING ACROSS THE N GULF. AT THE SURFACE...A RELATIVELY COOL AND DRY AIRMASS IS IN PLACE ACROSS THE GULF REGION...WITH TEMPERATURES GENERALLY BELOW SEASONAL AVERAGES. THIS AIRMASS IS BEING SUPPORTED BY A 1032 MB SURFACE HIGH OVER SOUTH CAROLINA NEAR 34N80W...WITH AN ASSOCIATED SURFACE RIDGE EXTENDING ACROSS THE NE GULF. SUBSIDENCE AND STABLE ATMOSPHERIC CONDITIONS ARE INHIBITING DEEP CONVECTION ACROSS THE GULF REGION. FARTHER NORTH...A VIGOROUS UPPER TROUGH IS OVER THE PLAINS OF THE CONUS...WITH AN ASSOCIATED SURFACE FRONT EXTENDING FROM THE SOUTHERN PLAINS OF THE CONUS TO THE ROCKY MOUNTAINS. AS THIS UPPER TROUGH TRANSLATES SOUTHEASTWARD OVER THE NEXT DAY...THE FRONT WILL APPROACH THE N GULF REGION. IN THE WAKE OF THIS FRONT...A REINFORCING COOLER AND DRIER AIRMASS...CHARACTERIZED AS A MODIFIED CONTINENTAL POLAR AIRMASS...IS PRESENT. ADDITIONALLY... STRONG N TO NE SURFACE WINDS ARE BLOWING THROUGH THE ISTHMUS OF TEHUANTEPEC RESULTING IN GALE FORCE WINDS IN THE E PACIFIC REGION. THESE WINDS ARE FORECAST TO HAVE DIMINISHED BELOW GALE FORCE AT 25/0600 UTC. CARIBBEAN SEA... IN THE SW CARIBBEAN...A 1007 MB SURFACE LOW NEAR 10N80W IS SUPPORTING SHOWER AND THUNDERSTORM ACTIVITY...WHICH IS DISCUSSED IN THE SPECIAL FEATURE SECTION ABOVE. THE INCREASED SURFACE PRESSURE GRADIENT ASSOCIATED WITH THIS SURFACE LOW IS SUPPORTING NE SURFACE WINDS OF 20 TO 30 KT FOR LOCATIONS FROM 12N-15N W OF 75W AND FOR LOCATIONS N OF 15N BETWEEN 69W-75W IN THE E CARIBBEAN INCLUDING THE WINDWARD PASSAGE...WHICH ARE EXPECTED TO CONTINUE THROUGH MONDAY NIGHT. THE SHOWER AND THUNDERSTORM ACTIVITY ASSOCIATED WITH THE SURFACE LOW 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 11N72W TO 15N78W TO THE NW CARIBBEAN NEAR 16N80W. A WEAKENING SURFACE STATIONARY FRONT IN THE NW CARIBBEAN EXTENDS FROM 20N80W TO E CUBA NEAR 21N76W...WITH SCATTERED SHOWERS WITHIN 60 NM OF THIS FRONT. OVER THE E AND CENTRAL CARIBBEAN...UPPER LEVEL DIFFLUENCE IS SUPPORTING SCATTERED SHOWERS AND THUNDERSTORMS S OF 16N BETWEEN 66W-71W. THIS ACTIVITY IS BEING ENHANCED BY LOW LEVEL CONVERGENCE ASSOCIATED WITH THE TROPICAL WAVE ALONG 74W DISCUSSED IN THE TROPICAL WAVES SECTION ABOVE. ATLANTIC OCEAN... AN UPPER LEVEL TROUGH OVER THE W ATLC IS SUPPORTING A SURFACE STATIONARY FRONT THAT EXTENDS FROM E CUBA NEAR 21N76W TO 25N60W TO 32N53W TO NE OF THE DISCUSSION AREA. ISOLATED SHOWERS ARE OCCURRING WITHIN 60 NM EITHER SIDE OF THIS FRONT. THIS FRONT IS WEAKENING W OF 71W. TO THE W OF THIS STATIONARY FRONT...A RELATIVELY COOLER AND DRIER AIRMASS IS IN PLACE...WITH TEMPERATURES BELOW SEASONAL AVERAGES ACROSS FLORIDA. THIS AIRMASS IS BEING SUPPORTED BY A 1032 MB SURFACE HIGH OVER SOUTH CAROLINA NEAR 34N80W. ALSO...A 1003 MB SURFACE LOW IS FORECAST TO FORM NEAR 32N53W OVER THE NEXT DAY. FARTHER TO THE E...A SURFACE TROUGH EXTENDS FROM 14N59W TO A 1011 MB SURFACE LOW NEAR 14N55W TO 13N50W. ISOLATED SHOWERS ARE OCCURRING WITHIN 60 NM OF THIS SURFACE LOW AND SURFACE TROUGH. TO THE E...AN UPPER TROUGH IS PRESENT OVER THE E ATLC N OF 20N E OF 44W WITH AN UPPER LOW NEAR 30N33W. AN ASSOCIATED SURFACE TROUGH EXTENDS FROM 28N35W TO A 1014 MB SURFACE LOW NEAR 22N35W TO 17N41W. LOW LEVEL CONVERGENCE NEAR THE SURFACE TROUGH AND SURFACE LOW IS SUPPORTING SCATTERED SHOWERS FROM 22N-29N BETWEEN 24W-35W. ALSO...UPPER LEVEL DIVERGENCE IN THE VICINITY OF A MID/UPPER-LEVEL WIND SPEED MAXIMUM OVER THE E ATLC IS SUPPORTING SCATTERED SHOWERS FROM 14N-19N BETWEEN 16W-27W. $$ COHEN