000 AXNT20 KNHC 142345 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 705 PM EST FRI NOV 14 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 2315 UTC. ...THE ITCZ... THE ITCZ AXIS IS ANALYZED ALONG 9N12W 7N22W 7N36W 9N49W 8N61W. A SURFACE TROUGH...WHICH EXTENDS FROM 13N55W TO 11N55W TO 8N56W...IS EMBEDDED WITHIN THE ITCZ. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS FROM 8N-13N BETWEEN 41W-57W...WHICH IS BEING ENHANCED BY THE COMBINATION OF ENHANCED LOW LEVEL CONVERGENCE NEAR THE SURFACE TROUGH AND UPPER LEVEL DIFFLUENCE. ELSEWHERE...SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS FROM 4N-27N BETWEEN BETWEEN 16W-33W. ...DISCUSSION... GULF OF MEXICO... A VIGOROUS UPPER-LEVEL SHORTWAVE TROUGH IS QUICKLY PROGRESSING EASTWARD ACROSS THE N GULF...WITH AN ASSOCIATED MID/UPPER-LEVEL WIND SPEED MAXIMUM E OF THE THE TROUGH AXIS. STRONG UPPER LEVEL DIVERGENCE TO THE NW OF THIS WIND SPEED MAXIMUM IS SUPPORTING A 1007 MB SURFACE LOW OVER S LOUISIANA NEAR 31N92W...AND A SURFACE TROUGH THAT EXTENDS TO THE S OF THIS LOW FROM 31N92W TO 28N93W TO 26N95W. THE COMBINATION OF THE LOW LEVEL CONVERGENCE IN THE VICINITY OF THE SURFACE LOW AND SURFACE TROUGH...AS WELL AS THE UPPER LEVEL DIVERGENCE...IS SUPPORTING SCATTERED SHOWERS AND THUNDERSTORMS OVER THE NORTH CENTRAL GULF N OF 27N BETWEEN 88W-93W. IN THE WAKE OF THE SURFACE TROUGH...A 1010 MB SURFACE HIGH IS OVER SE TEXAS NEAR 29N95W...WITH DEEP LAYER SUBSIDENCE IN NORTHWESTERLY FLOW ALOFT AND DEEP LAYER DRY AIR BRINGING FAIR WEATHER CONDITIONS OVER THE NW GULF. ALSO...DEEP LAYER DRY AIR IS LIMITING DEEP CONVECTION ACROSS MUCH OF THE SE GULF. OVER THE NEXT DAY...A DEEP LAYER TROUGH AND ASSOCIATED STRONG SURFACE COLD FRONT...CURRENTLY OVER THE PLAINS OF THE CONUS...WILL MOVE ACROSS THE NW GULF...WITH STRONG SURFACE HIGH PRESSURE BUILDING IN THE WAKE OF THE FRONT. AT THE SAME TIME...PARTICULARLY STRONG MID/UPPER-LEVEL FLOW ACCOMPANYING THE DEEP LAYER TROUGH WILL ALSO MOVE ACROSS THE NW GULF OVER THE NEXT DAY. THESE FACTORS ARE FORECAST TO RESULT IN STRONG NORTHERLY WINDS TO GALE FORCE FOR LOCATIONS W OF THE COLD FRONT IN THE W GULF IN 24 HOURS. ALSO OF NOTE...THE INTERACTION OF UPPER LEVEL DIVERGENCE ASSOCIATED WITH THE AFOREMENTIONED SHORTWAVE TROUGH OVER THE N GULF...AND LOW LEVEL CONVERGENCE ASSOCIATED WITH BOTH A FRONT OVER THE SE CONUS AND THE REMNANT LOW LEVEL CIRCULATION OF PALOMA...RESULTED IN SHOWERS AND THUNDERSTORMS WITH HEAVY RAINFALL OVER THE FLORIDA PANHANDLE EARLIER TODAY. IN FACT...A TOTAL OF 9 INCHES OF RAIN ARE REPORTED TO HAVE FALLEN THIS MORNING ABOUT 15 NM W OF TALLAHASSEE FLORIDA. CARIBBEAN SEA... AN UPPER RIDGE IS AFFECTING THE W CARIBBEAN...WITH THE UPPER RIDGE AXIS EXTENDING FROM CENTRAL CUBA NEAR 22N79W TO N HONDURAS NEAR 15N86W. SUBSIDENCE AND DEEP LAYER DRY AIR IN THE VICINITY OF THIS UPPER RIDGE ARE BRINGING FAIR WEATHER CONDITIONS TO MUCH OF THE W CARIBBEAN. OVER THE E CARIBBEAN...AN UPPER LEVEL TROUGH IS PRESENT...WHICH EXTENDS FROM AN UPPER LOW NEAR 13N71W TO PUERTO RICO NEAR 18N67W NORTHEASTWARD INTO THE SW ATLC. WEAK INSTABILITY...COMBINED WITH GREATER DEEP MOISTURE OVER THE E CARIBBEAN...IS SUPPORTING ISOLATED SHOWERS E OF 71W...INCLUDING PORTIONS OF THE LESSER ANTILLES...PUERTO RICO...AND HISPANIOLA. THIS ACTIVITY IS FURTHER BEING ENHANCED BY A SURFACE TROUGH THAT EXTENDS FROM NE OF THE DOMINICAN REPUBLIC NEAR 19N68W FURTHER NORTHEAST INTO THE SW ATLC. ALSO...SCATTERED SHOWERS AND THUNDERSTORMS ARE OCCURRING OVER PORTIONS OF NE COLOMBIA...AS WELL AS THE ADJACENT CARIBBEAN SEA. THIS ACTIVITY IS BEING ENHANCED BY GREATER INSTABILITY OVER HIGHER TERRAIN. ATLANTIC OCEAN... AN UPPER RIDGE AXIS IS OVER THE W ATLC EXTENDING FROM CENTRAL CUBA NEAR 22N79W TO 28N72W TO 32N67W TO NE OF THE DISCUSSION AREA. DEEP LAYER DRY AIR IS INHIBITING DEEP CONVECTION ACROSS MUCH OF THE W ATLC. FARTHER TO THE E...THE AXIS OF A DEEP LAYER TROUGH EXTENDS FROM PUERTO RICO NEAR 18N67W TO 22N60W TO 26N53W. THIS DEEP LAYER TROUGH IS ACCOMPANIED BY A SURFACE TROUGH THAT EXTENDS FROM NE OF THE DOMINICAN REPUBLIC NEAR 19N68W TO 23N68W TO 25N67W. LOW LEVEL CONVERGENCE NEAR THIS SURFACE TROUGH IS SUPPORTING SCATTERED SHOWERS AND THUNDERSTORMS FROM 19N-25N BETWEEN 63W-71W...INCLUDING PORTIONS OF THE LESSER ANTILLES...PUERTO RICO...AND HISPANIOLA. ALSO...AN UPPER LEVEL TROUGH IS N OF 21N BETWEEN 30W-45W...WITH A COLD FRONT EXTENDING FROM 31N41W TO NE OF THE DISCUSSION AREA AND A SURFACE TROUGH EXTENDING FROM 31N37W TO 27N38W TO 24N38W. ATMOSPHERIC LIFT ASSOCIATED WITH THESE FEATURES IS SUPPORTING ISOLATED SHOWERS AND THUNDERSTORMS N OF 27N BETWEEN 32W-46W. OVER THE TROPICAL ATLC...AN UPPER HIGH IS CENTERED NEAR 2N45W...AND AN UPPER RIDGE IS S OF 10N BETWEEN 26W-39W. UPPER LEVEL DIFFLUENCE ASSOCIATED WITH THESE FEATURES IS ENHANCING THE CONVECTION IN THE VICINITY OF THE SURFACE TROUGH EMBEDDED WITHIN THE ITCZ. $$ COHEN