000 AXNT20 KNHC 281746 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 105 PM EST SAT JAN 28 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 1730 UTC. ...THE ITCZ/THE MONSOON TROUGH... MOST OF THE MONSOON TROUGH EXTENDS ACROSS AFRICA THIS AFTERNOON... WITH A SMALL PORTION OF IT EXTENDING INTO THE E TROPICAL ATLC ALONG THE COAST OF SIERRA LEONE NEAR 8N13W TO 8N15W...WHERE THE ITCZ AXIS CONTINUES ALONG 3N30W TO INLAND OVER BRAZIL NEAR 1N50W. CLUSTERS OF SCATTERED MODERATE CONVECTION ARE WITHIN 100 NM ON EITHER SIDE OF THE ITCZ W OF 23W. ...DISCUSSION... GULF OF MEXICO... BROAD UPPER CYCLONIC FLOW COVERS THE CONUS EXTENDING S TO THE GULF OF MEXICO...WITH STRONG SUBSIDENCE AND DRY STABLE AIR OVER THE NW BASIN. THIS FEATURE SUPPORTS A NEAR STATIONARY FRONTAL BOUNDARY JUST S OF THE FLORIDA KEYS TO ALONG THE NW COASTAL WATERS OF CUBA THROUGH THE YUCATAN CHANNEL...BECOMING WEAK AS IT ENTERS THE NE YUCATAN PENINSULA. DOPPLER RADAR IMAGERY INDICATES SCATTERED SHOWERS WITH A FEW ISOLATED THUNDERSTORMS OCCURRING WITHIN 75 NM NW OF THE BOUNDARY. WEAK SURFACE RIDGING ANCHORED IN THE SE CONUS ALONG WITH THE DRY/SUBSIDENT UPPER ATMOSPHERE IS KEEPING THE REMAINDER OF THE GULF WITH MOSTLY CLEAR SKIES THIS EARLY AFTERNOON. THE STATIONARY FRONT WILL SLOWLY DISSIPATE THROUGH EARLY NEXT WEEK. THE WEAK RIDGING WILL BE REPLACED BY STRONGER HIGH PRESSURE THAT BEGINS TO BUILD ACROSS THE AREA LATER THIS AFTERNOON. THIS HIGH PRESSURE AREA WILL THEN CONTINUE TO BUILD E ACROSS THE GULF INTO EARLY NEXT WEEK. SOUTHERLY RETURN FLOW THEN SETS UP OVER THE NW GULF LATE MON THROUGH WED. CARIBBEAN SEA... BROAD UPPER RIDGE CENTERED JUST N OF PUERTO RICO IS GIVING THE CARIBBEAN SW TO W FLOW ALOFT. WATER VAPOR IMAGERY SHOWS STRONG SUBSIDENCE WITH DRY STABLE AIR ACROSS THE BASIN WITH THE EXCEPTION OF THE FAR NW AREA WHERE THE NEAR STATIONARY FRONT OVER THE SE GULF OF MEXICO EXTENDS THROUGH THE YUCATAN CHANNEL TO INLAND OVER THE YUCATAN PENINSULA...WITH POSSIBLE ISOLATED SHOWERS WITHIN 30 NM SE OF THE FRONT. MARINE OBSERVATIONS AND VISIBLE SATELLITE IMAGERY SHOW GENTLE TO MODERATE EASTERLY TRADE WINDS WITH A FEW POCKETS LOW LEVEL MOISTURE AND POSSIBLE ISOLATED WEAK ACROSS THE AREA. OTHERWISE...THE REMAINDER OF THE CARIBBEAN IS UNDER FAIR WEATHER THIS AFTERNOON. THE WEAK STATIONARY FRONT WILL SLOWLY DISSIPATE THROUGH TUE. STRONG HIGH PRESSURE WILL BUILD SE ACROSS MUCH OF THE N CARIBBEAN THROUGH WED. ATLANTIC OCEAN... THE BROAD CYCLONIC FLOW ALOFT THAT COVERS THE CONUS SUPPORTS AN UPPER LONGWAVE MOVING OFF THE ERN CONUS SEABOARD. THIS FEATURE FURTHER SUPPORTS A NEARLY STATIONARY FRONT THAT ENTERS THE DISCUSSION AREA NEAR 32N70W CONTINUING SW ACROSS THE NW BAHAMAS NEAR 26N78W INTO THE STRAITS OF FLORIDA AND THE FAR SE GULF OF MEXICO. SCATTERED SHOWERS AND POSSIBLE ISOLATED THUNDERSTORMS ARE WITHIN 30 NM ON EITHER SIDE OF THE FRONT N OF 25N E OF 80W. THE REMAINDER OF THE W AND CENTRAL ATLC W OF 37W ARE DOMINATED BY A SURFACE RIDGE ANCHORED BY A 1025 MB HIGH NEAR 28N57W...GIVING THE AREA FAIR WEATHER THIS AFTERNOON. A NARROW UPPER TROUGH DIPS S OVER THE ERN ATLC N OF 19N BETWEEN 30W-40W SUPPORTING A FRONTAL BOUNDARY THAT EXTENDS INTO THE AREA AS A SURFACE TROUGH FROM 31N32W TO 20N31W GENERATING CLUSTERS OF SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS WITHIN 100 NM ON EITHER SIDE OF IT N OF 22N. A SURFACE RIDGE DOMINATES THE FAR E ATLC ANCHORED BY A 1034 MB HIGH WELL N OF THE DISCUSSION AREA. THE W ATLC FRONT WILL START TO MOVE SLOWLY EASTWARD THROUGH EARLY SUN. STRONG HIGH PRESSURE WILL BEGIN TO BUILD E ACROSS THE W ATLC ON SUN. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ GARCIA