000 AXNT20 KNHC 211735 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 105 PM EST TUE DEC 21 2010 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 1715 UTC. ...THE ITCZ... ITCZ AXIS IS CENTERED FROM LIBERIA NEAR 5N9W ALONG 3N27W 3N40W 1N53W. NUMEROUS MODERATE/SCATTERED STRONG CONVECTION IS FROM 1S-3N BETWEEN 8W-12W...AND FROM 2N-7N BETWEEN 12W-18W. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS FROM 3N-5N BETWEEN 23W-27W. ISOLATED MODERATE/STRONG CONVECTION IS FROM 3N-7N BETWEEN 42W-48W. NUMEROUS MODERATE/STRONG CONVECTION IS FROM EQ-5N BETWEEN 50W-53W. ...DISCUSSION... GULF OF MEXICO... MAINLY NWLY FLOW ALOFT COVERS THE GULF OF MEXICO TODAY AROUND THE ERN HALF OF AN UPPER LEVEL RIDGE COVERING MUCH OF THE CENTRAL UNITED STATES. THE UPPER RIDGE SUPPORTS A SURFACE RIDGE ANCHORED BY A 1023 MB HIGH OVER NRN FLORIDA AND SRN GEORGIA NEAR 31N83W. WEAK ANTI-CYCLONIC FLOW IS AROUND THE RIDGE WITH STRONGER SLY WINDS UP TO 15 KTS ALONG THE TEXAS COASTLINE. DRY AIR AND SUBSIDENCE ALOFT ARE MAINTAINING MOSTLY CLEAR SKIES ACROSS THE BASIN WITH THE EXCEPTION OF AN AREA OF STRATOCUMULUS CLOUDS IN THE N CENTRAL GULF N OF 27N BETWEEN 86W-95W. EXPECT SURFACE RIDGING TO DOMINATE THE BASIN FOR THE NEXT SEVERAL DAYS KEEPING CONDITIONS FAIR. CARIBBEAN SEA... DRY AIR AND SUBSIDENCE ALOFT THAT COVERS THE GULF OF MEXICO IS ALSO IMPACTING MUCH OF THE WRN CARIBBEAN KEEPING CONDITIONS FAIR. A LONGWAVE UPPER TROUGH OVER THE W ATLC SUPPORTS A COLD FRONT THAT CROSSES THE NRN LEEWARD ISLANDS NEAR ANTIGUA ALONG 17N61W TO 16N65W WHERE IT CONTINUES AS A SURFACE TROUGH ALONG 15N67W 13N67W. SCATTERED SHOWERS/POSSIBLE THUNDERSTORMS ARE WITHIN 45 NM EITHER SIDE OF THE AXIS. A SECOND SURFACE TROUGH IS FARTHER W ALONG 17N72W TO 13N70W...AS INDICATED BY A WINDSAT SCATTEROMETER PASS. THE PASS REVEALS N-NE WINDS UP TO 20 KTS ARE NE OF THE TROUGH AXIS WITH WEAKER WINDS TO THE SW. CONVERGENCE NEAR THE TROUGH IS SUPPORTING SCATTERED SHOWERS/POSSIBLE THUNDERSTORMS WITHIN 45 NM EITHER SIDE OF THE AXIS. POSSIBLE ISOLATED SHOWERS ARE ALSO N OF 16N BETWEEN 63W-69W. EXPECT SHOWER ACTIVITY TO CONTINUE ACROSS PORTIONS OF THE ERN CARIBBEAN...AS WELL AS ACROSS THE SRN WINDWARD ISLANDS AS A LOW PRESSURE SYSTEM SE OF BARBADOS MOVES WWD OVER THE NEXT 24 HRS. ATLANTIC OCEAN... SURFACE RIDGING CENTERED OVER NRN FLORIDA/SRN GEORGIA EXTENDS OVER THE FAR W ATLC KEEPING CONDITIONS FAIR. A DEEP LAYER TROUGH IS TO THE E SUPPORTING A BROAD LOW PRESSURE SYSTEM CENTERED OFF THE NEW ENGLAND COAST WITH AN ASSOCIATED COLD FRONT ENTERING THE DISCUSSION AREA NEAR 32N51W CONTINUING TO THE NRN LEEWARD ISLANDS ALONG 25N53W 17N62W. SCATTERED SHOWERS/POSSIBLE THUNDERSTORMS ARE WITHIN 250 NM AHEAD OF THE FRONT N OF 23N...AND WITHIN 120 NM AHEAD OF THE FRONT S OF 23N. GALE FORCE WINDS ARE BOTH AHEAD OF AND BEHIND THE FRONT WITH A LARGE AREA OF STRATOCUMULUS CLOUDS ALSO BEHIND THE FRONT. TO THE S...A 1010 MB LOW IS LOCATED NEAR BARBADOS AT 12N59W WITH A SURFACE TROUGH EXTENDING THROUGH THE CENTER ALONG 16N56W TO 9N62W. AN AREA OF STRONG SHOWERS/THUNDERSTORMS ARE W OF THE SYSTEM WITHIN 100 NM...AND SHOULD BEGIN IMPACTING THE WINDWARD ISLANDS SHORTLY AS THE SYSTEM PROGRESSES WWD. ACROSS THE ERN ATLC...A BROAD UPPER LEVEL RIDGE ALONG 39W SUPPORTS A SURFACE RIDGE ANCHORED BY A 1020 MB HIGH NEAR 25N37W PROVIDING GENERALLY FAIR WEATHER ACROSS THIS PORTION OF THE BASIN. AN UPPER LEVEL TROUGH IS TO THE E ACROSS THE CANARY ISLANDS TO THE CAPE VERDE ISLANDS SUPPORTING A LOW PRESSURE SYSTEM N OF THE DISCUSSION AREA THAT IS GENERATING CYCLONIC SURFACE FLOW N OF 25N. A SURFACE TROUGH DEPICTS THE SHIFTING CYCLONIC WINDS ALONG 31N16W TO 24N27W. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ WALTON