000 AXNT20 KNHC 221115 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 705 AM EST SAT NOV 22 2014 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 1145 UTC. ...THE ITCZ/THE MONSOON TROUGH... THE ITCZ EXTENDS FROM 9N14W TO 7N30W 7N41W TO 6N57W. SCATTERED MODERATE CONVECTION AND ISOLATED TSTMS ARE FROM 4N-11N E OF 33W. SCATTERED MODERATE CONVECTION IS FROM 4N-8N WEST OF 33W. ...DISCUSSION... ...THE GULF OF MEXICO... A MIDDLE- TO UPPER-LEVEL RIDGE OVER THE EASTERN CONUS CONTINUES TO SUPPORT A BROAD SURFACE ANTICYCLONE ANCHORED BY A 1035 MB HIGH OVER EASTERN VIRGINIA...WHICH EXTENDS A RIDGE SW ACROSS FLORIDA TO THE SOUTHERN GULF OF MEXICO. A TIGHT PRESSURE GRADIENT BETWEEN THE RIDGE AND A FRONTAL BOUNDARY ACROSS THE SW N ATLC TO THE STRAITS OF FLORIDA SUPPORT E-NE WIND FLOW OF 20 KT WHILE A MORE RELAXED PRESSURE GRADIENT WEST OF 90W PROVIDES FOR E-SE WIND FLOW OF 15 KT. DEEP LAYER DRY AIR IN THE NORTHERN GULF N OF 27N E OF 93W MAINTAINS FAIR WEATHER IN THIS REGION. MIDDLE- TO LOW-LEVEL MOISTURE ADVECTION FROM THE CARIBBEAN SEA AS WELL AS UPPER-LEVEL MOISTURE STREAMING NE FROM THE E PAC WATERS SUPPORT CLOUDINESS AND SCATTERED SHOWERS ACROSS THE REMAINDER GULF. A STATIONARY FRONT EXTENDING ACROSS THE CENTRAL BAHAMAS WESTWARD TO THE STRAITS OF FLORIDA SUPPORT SIMILAR CONVECTION THERE. AS THE SURFACE RIDGE ANCHORED OVER VIRGINIA CONTINUES TO DRIFT SE DURING THE NEXT TWO DAYS...A COLD FRONT STARTS ENTERING THE NW BASIN EARLY MONDAY. ...THE CARIBBEAN SEA... SHALLOW MOISTURE MOVES ACROSS THE CENTRAL AND WESTERN CARIBBEAN SEA...HOWEVER DRY AIR SUBSIDENCE ASSOCIATED WITH AN UPPER-LEVEL ANTICYCLONE OVER THIS REGION HINDER THE DEVELOPMENT OF CONVECTION. ISOLATED SHOWERS ARE NOTED WITHIN 20 NM OF THE COASTS OF BELIZE...HONDURAS AND NICARAGUA. AN UPPER-LEVEL LOW OVER THE NE BASIN ALONG WITH A BROAD MOIST AIRMASS MOVING ACROSS THE EASTERN CARIBBEAN CONTINUE TO SUPPORT SCATTERED HEAVY SHOWERS OVER THE LESSER ANTILLES AND THE VIRGIN ISLANDS. SIMILAR CONVECTION IS EXPECTED FOR PUERTO RICO AND ADJACENT WATERS TODAY THROUGH SATURDAY. ...HISPANIOLA... CURRENTLY FAIR WEATHER IS ACROSS THE ISLAND AND ADJACENT WATERS BEING INFLUENCED BY DRY AIR SUBSIDENCE ASSOCIATED WITH AN UPPER- LEVEL ANTICYCLONE OVER THE WESTERN AND CENTRAL CARIBBEAN. HOWEVER...BY SATURDAY MORNING...A BROAD AND MOIST AIRMASS STARTS TO MOVE ACROSS THE ISLAND ENHANCING SCATTERED HEAVY SHOWERS AND TSTMS. SHOWERS ASSOCIATED WITH THE PASSAGE OF THIS AIRMASS ACROSS THE ISLAND ARE FORECAST THROUGH SUNDAY NIGHT. ...THE ATLANTIC OCEAN... A BROAD MIDDLE- TO UPPER-LEVEL TROUGH OVER THE NW ATLC CONTINUES TO SUPPORT A COLD FRONT ALONG 30N55W SW TO 26N64W TO 24N72W WHERE IT TRANSITIONS TO A STATIONARY FRONT TO THE STRAITS OF FLORIDA. SCATTERED SHOWERS ARE WITHIN 180 NM WEST OF THE FRONTAL BOUNDARY...SIMILAR SHOWER ACTIVITY IS WITHIN 180 NM EAST OF THE FRONT N OF 28N. SCATTERED HEAVY SHOWERS AND ISOLATED TSTMS ARE WITHIN 100 NM N OF THE VIRGIN ISLANDS AND 120 NM EAST OF THE LESSER ANTILLES BEING ENHANCED BY A BROAD MOIST AIRMASS MOVING ACROSS THE EASTERN CARIBBEAN AND AN UPPER-LEVEL LOW OVER THE NE BASIN. ON THE FAR NE ATLC BASIN...A 1003 MB LOW IS NE OF THE CANARY ISLANDS SUPPORTING SCATTERED SHOWERS N OF 27N E OF 14W. SURFACE RIDGING DOMINATES ELSEWHERE ACROSS THE BASIN N OF 20N. A RIDGE ANCHORED OVER VIRGINIA MOVING SE OVER THE NEXT COUPLE OF DAYS WILL PUSH THE COLD FRONT TOWARDS THE CENTRAL ATLC WHERE IT WILL DISSIPATE MONDAY NIGHT. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ NR