000 AXNT20 KNHC 151727 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 105 PM EST SAT JAN 15 2011 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 1630 UTC. ...THE ITCZ... ITCZ AXIS EXTENDS ALONG 3N8W 5N18W CROSSING THE EQUATOR NEAR 27W CONTINUING S OF THE EQUATOR ALONG 2S35W CROSSING BACK NEAR 47W TO 1N52W. ISOLATED MODERATE CONVECTION IS WITHIN 60 NM EITHER SIDE THE AXIS BETWEEN 20W-26W. SIMILAR ACTIVITY IS WITHIN 100 NM N OF THE AXIS BETWEEN 28W-38W. SCATTERED MODERATE/STRONG CONVECTION IS FROM EQ-3N BETWEEN 41W-49W. ...DISCUSSION... THE GULF OF MEXICO... SURFACE RIDGING AROUND A 1029 MB HIGH CENTERED OVER ALABAMA CONTINUES TO DOMINATE THE GULF OF MEXICO TODAY LEAVING MOSTLY FAIR CONDITIONS ACROSS THE AREA. HOWEVER...A SURFACE TROUGH HAS FORMED ACROSS SRN TEXAS AND NE MEXICO SUPPORTED BY A NARROW POSITIVELY TILTED UPPER SHORTWAVE TROUGH EXTENDING FROM ARKANSAS TO WRN TEXAS. THIS SYSTEM IS SUPPORTING SCATTERED SHOWERS MAINLY W OF 95W N OF 23N ALONG THE NW CORNER OF THE BASIN. CLEAR SKIES SPREAD ACROSS THE CENTRAL GULF AS WELL AS THE FAR SE CORNER OVER S FLORIDA. AN AREA OF LOW-MID LEVEL CLOUDS WITH POSSIBLE ISOLATED SHOWERS ARE S OF 27N BETWEEN 84W-88W. A RECENT WINDSAT SCATTEROMETER PASS INDICATES THAT A WEAK SURFACE TROUGH HAS FORMED IN THIS AREA WHICH MAY BE A REFLECTION OF A VERY WEAK AND SPATIALLY SMALL UPPER TROUGH EMBEDDED IN OTHERWISE ZONAL WLY FLOW ALOFT ACROSS THE BASIN. EXPECT LITTLE CHANGE OVER THE NEXT 24 HOURS. THE CARIBBEAN SEA... LITTLE ACTIVE WEATHER IS NOTED ACROSS THE CARIBBEAN TODAY AS A MOSTLY DRY AIR MASS COVERS THE BASIN WITH MAINLY ZONAL WLY FLOW ALOFT. PATCHES OF LOW CLOUDS AND POSSIBLE ISOLATED SHOWERS ARE ACROSS THE NW PORTION OF THE BASIN. NELY TRADEWINDS ARE ACROSS THE ERN HALF OF THE AREA BROADLY TURNING MORE NLY W OF 75W. A WEAKENING SHEAR LINE IS NOTED ACROSS FAR WRN CUBA SUPPORTING A FEW SCATTERED SHOWERS N OF 20N BETWEEN 74W-77W. EXPECT LITTLE CHANGE OVER THE NEXT 24 HOURS. THE ATLANTIC OCEAN... SURFACE RIDGING EXTENDING FROM THE SE CONUS COVERS THE FAR W ATLC TODAY. A BROAD LOW PRESSURE SYSTEM IS TO THE E SUPPORTING A COLD FRONT SPREADING FROM 32N38W TO 30N47W BECOMING STATIONARY TO 27N59W CONTINUING AS A SHEAR LINE TO THE SE BAHAMAS AND WRN CUBA. SCATTERED SHOWERS ARE WITHIN 70 NM EITHER SIDE OF THE FRONTAL BOUNDARY...AND WITHIN 90 NM EITHER SIDE OF THE SHEAR AXIS. THE SYSTEM IS SUPPORTED BY A BROAD AND SHALLOW UPPER LEVEL TROUGH ACROSS THE WRN ATLC. DRY AIR AND SUBSIDENCE IS TO EITHER SIDE OF THE BAND OF MOISTURE THAT SPREADS FROM THE SE BAHAMAS TO NEAR 34N45W. THE REMAINDER OF THE CENTRAL AND ERN ATLC IS COVERED BY A SURFACE RIDGE AROUND A 1023 MB HIGH S OF THE FRONTAL BOUNDARY NEAR 26N45W MAINTAINING FAIR CONDITIONS ACROSS THIS HALF OF THE BASIN. ALOFT...A BROAD UPPER RIDGE EXTENDS FROM N OF BRAZIL NEAR 7N52W TOWARDS THE AZORES ISLANDS. A NARROW UPPER TROUGH IS TO THE E EXTENDING FROM PORTUGAL TO THE CANARY AND CAPE VERDE ISLANDS...BUT IT IS NOT SUPPORTING ANY SENSIBLE WEATHER CURRENTLY. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ WALTON