000 AXNT20 KNHC 221752 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 105 PM EST THU NOV 22 2012 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...WEATHER OBSERVATIONS...RADAR...AND METEOROLOGICAL ANALYSIS. BASED ON 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 1715 UTC. ...ITCZ/MONSOON TROUGH... THE MONSOON TROUGH EXTENDS ACROSS W AFRICA INTO THE E TROPICAL ATLC NEAR 9N13W TO 7N17W WHERE THE ITCZ BEGINS AND CONTINUES ALONG 5N27W TO 7N48W. A SURFACE TROUGH IS DISRUPTING THE ITCZ FROM 11N49W ALONG 7N51W TO 5N50W. CLUSTERS OF SCATTERED MODERATE CONVECTION ARE FROM 6N-10N BETWEEN 48W-55W. SCATTERED MODERATE/ ISOLATED STRONG CONVECTION IS FROM 2N-4N BETWEEN 13W-16W. CLUSTERS OF SCATTERED MODERATE TO ISOLATED STRONG CONVECTION ARE WITHIN 200 NM S OF THE ITCZ BETWEEN 20W-33W AND WITHIN 225 NM N OF THE ITCZ BETWEEN 21W-48W. ...DISCUSSION... GULF OF MEXICO... A SHORTWAVE UPPER TROUGH IN THE W ATLC EXTENDS W OVER THE FLORIDA PENINSULA DRAWING DRY CONTINENTAL AIR OVER THE E GULF OF MEXICO AND ESPECIALLY THE FLORIDA. NEAR ZONAL WESTERLY FLOW ALOFT COVERS THE REMAINDER OF THE GULF. A SURFACE TROUGH IS IN THE SW GULF EXTENDING ALONG THE COAST OF MEXICO FROM NEAR TAMPICO TO COATZACOALCOS. SCATTERED SHOWERS ARE WITHIN 60 NM EITHER SIDE OF THE TROUGH. OTHERWISE A SURFACE RIDGE DOMINATES THE GULF ANCHORED BY A SERIES OF HIGHS STRETCHING FROM NEW ENGLAND TO A 1025 MB HIGH OVER MISSISSIPPI. THIS IS GIVING MOST OF THE GULF CLEAR SKIES THIS AFTERNOON. THE SURFACE RIDGE WILL WEAKEN THROUGH FRI. COLD FRONT WILL MOVE INTO FAR NW GULF LATE FRI REACHING FROM TAMPA FLORIDA TO S TEXAS SAT THEN FROM STRAITS OF FLORIDA TO S TEXAS EARLY SUN WHERE IT STALL AND DISSIPATE. HIGH PRESSURE WILL REBUILD E ACROSS REGION BEHIND FRONT. CARIBBEAN SEA... A BROAD UPPER RIDGE DOMINATES MOST OF THE CARIBBEAN ANCHORED OVER S VENEZUELA AND EXTENDING A RIDGE AXIS NNE ACROSS THE LEEWARD/VIRGIN ISLANDS INTO THE CENTRAL ATLC. A SURFACE TROUGH EXTENDS FROM THE MONA PASSAGE ALONG 15N71W TO THE COAST OF COLOMBIA NEAR 12N73W. MOIST SW FLOW ALOFT COVERS THE SW CARIBBEAN AND COUPLED WITH THE RESULTING NE SURFACE FLOW ARE GENERATING SCATTERED SHOWERS AND POSSIBLE ISOLATED THUNDERSTORMS S OF 13N W OF 75W TO INLAND OVER PANAMA AND COSTA RICA. THE MONSOON TROUGH EXTENDS INLAND OVER PANAMA AND COSTA RICA FURTHER ENHANCING THE ACTIVITY DESCRIBED ABOVE. NORTHERLY SURFACE FLOW W OF THE SURFACE TROUGH ARE GENERATING ISOLATED SHOWERS AND POSSIBLE ISOLATED THUNDERSTORMS WITHIN 225 NM W OF THE SURFACE TROUGH. SURFACE RIDGE OVER THE GULF OF MEXICO EXTENDS TO OVER THE W CARIBBEAN. GENTLE TO MODERATE E TRADE WINDS PREVAIL OVER E AND CENTRAL CARIBBEAN THROUGH FRI. SURFACE RIDGE WILL REMAIN THROUGH SAT MAINTAINING TIGHT PRESSURE GRADIENT AND FRESH N WINDS OVER W CARIBBEAN. TRADE WINDS WILL INCREASE OVER CENTRAL CARIBBEAN BY SAT AND SUN BUT WEAKEN SOME W CARIBBEAN AS ATLC SURFACE RIDGE STRENGTHENS. ATLANTIC OCEAN... A NARROW SHORTWAVE UPPER TROUGH EXTENDS OVER THE FAR W ATLC COVERING THE AREA W OF 68W TO OVER THE FLORIDA PENINSULA SUPPORTING A NEWLY DEVELOPED COLD FRONT THAT EXTENDS FROM A 1004 MB LOW NEAR 33N68W ALONG 30N68W ACROSS THE TURKS AND CAICOS TO THE NE TIP OF CUBA. A WEAK 1008 MB SURFACE LOW IS W OF THE FRONT NEAR 28N76W WITH A SURFACE TROUGH EXTENDING S TO THE CENTRAL BAHAMAS NEAR 25N77W. THE AREA IS DOMINATED BY A SWATH OF DRY STABLE AIR ALOFT THAT EXTENDS FROM OVER FLORIDA AND W CUBA TO OVER THE CENTRAL ATLC. HOWEVER...ISOLATED LOW LEVEL SHOWERS ARE POSSIBLE N OF 24N W OF 73W. A BROAD UPPER TROUGH IS IN THE E/CENTRAL ATLC N OF 24N BETWEEN 26W-42W SUPPORTING A COLD FRONT THAT EXTENDS THROUGH 32N34W TO 27N41W. SCATTERED SHOWERS AND POSSIBLE ISOLATED THUNDERSTORMS ARE WITHIN 180 NM E OF THE FRONT. A REMNANT SURFACE TROUGH IS TO THE SW EXTENDING FROM 26N50W ALONG 23N58W TO 20N64W WITH SCATTERED SHOWERS WITHIN 60 NM EITHER SIDE OF THE TROUGH. A SURFACE RIDGE DOMINATES THE FAR E ATLC E OF 30W. ANOTHER COLD FRONT WILL ENTER NW WATERS FRI NIGHT INTO SAT REACHING FROM 32N63W TO STRAITS OF FLORIDA EARLY SUN AND WEAKEN THEN STALL WHILE DISSIPATING FROM 32N58W TO CENTRAL CUBA EARLY MON. HIGH PRESSURE WILL REBUILD ACROSS AREA IN WAKE OF FRONT. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ PAW