000 AXNT20 KNHC 211747 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 105 PM EST THU NOV 21 2013 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. ...SPECIAL FEATURE... THE CENTER OF TROPICAL STORM MELISSA AT 21/1545 UTC IS NEAR 40.1N 34.5W...ABOUT 156 NM WNW OF FLORES ISLAND IN THE AZORES. MELISSA IS MOVING EAST-NORTHEASTWARD 28 KNOTS. THE ESTIMATED MINIMUM CENTRAL PRESSURE IS 984 MB. THE MAXIMUM SUSTAINED WIND SPEEDS ARE 55 KNOTS WITH GUSTS TO 65 KNOTS. PUBLIC ADVISORIES ON TROPICAL STORM MELISSA ARE ISSUED UNDER WMO HEADER WTNT34 KNHC AND UNDER AWIPS HEADER MIATCPAT4. FORECAST/ADVISORIES ON TROPICAL STORM MELISSA ARE ISSUED UNDER WMO HEADER WTNT24 KNHC AND UNDER AWIPS HEADER MIATCMAT4. GALE-FORCE WINDS ARE EXPECTED TO AFFECT THE WESTERN AND CENTRAL AZORES BEGINNING TODAY. SCATTERED MODERATE CONVECTION IS FROM 39N-41N BETWEEN 33W-35W. ...THE ITCZ/THE MONSOON TROUGH... THE MONSOON TROUGH PASSES ACROSS COASTAL SIERRA LEONE NEAR 8N13W TO 3N18W. THE ITCZ CONTINUES FROM 3N18W TO 5N30W TO 5N40W TO THE COAST OF N BRAZIL AT 1N50W. SCATTERED MODERATE TO ISOLATED STRONG CONVECTION IS FROM 1N-7N BETWEEN 22W-35W. ...DISCUSSION... GULF OF MEXICO... THE TAIL END OF A COLD FRONT IS OVER S FLORIDA FROM 25N80W TO 25N83W. SCATTERED SHOWERS ARE WITHIN 15 NM OF THE FRONT. RADAR IMAGERY ALSO SHOWS SCATTERED SHOWERS OVER CENTRAL FLORIDA FROM 26N-30N E OF 82W. THE REMAINDER OF THE GULF IS DOMINATED BY SURFACE RIDGING PRODUCING 10-15 KT E TO SE WINDS. PATCHES OF ISOLATED MODERATE CONVECTION ARE OVER THE NE GULF NEAR 28N86W...THE NW GULF NEAR 29N94W...AND THE BAY OF CAMPECHE NEAR 20N94W. IN THE UPPER LEVELS...RIDGING IS PRODUCING SW TO W UPPER LEVEL FLOW WITH A GOOD AMOUNT OF UPPER LEVEL MOISTURE. EXPECT OVER THE NEXT 24 HOURS FOR MORE CONVECTION OR SHOWERS TO BE OVER S FLORIDA AND THE SE GULF...AND OVER THE W GULF W OF 92W. CARIBBEAN SEA... A SURFACE TROUGH IS OVER THE W CARIBBEAN FROM 18N79W TO PANAMA AT 9N79W. SCATTERED SHOWERS ARE WITHIN 120 NM OF THE TROUGH TO INCLUDE OVER JAMAICA. A MONSOON TROUGH EXTENDS FROM N COLOMBIA AT 7N75W TO BEYOND COSTA RICA AT 9N84W. SCATTERED SHOWERS ARE WITHIN 90 NM OF THIS TROUGH. ELSEWHERE...SCATTERED MODERATE CONVECTION IS OVER THE LEEWARD ISLANDS FROM 17N-19N BETWEEN 62W- 65W TO INCLUDE THE VIRGIN ISLANDS. IN THE UPPER LEVELS...AN UPPER LEVEL RIDGE IS OVER THE W CARIBBEAN SEA W OF 73W. AN UPPER LEVEL TROUGH IS OVER THE E CARIBBEAN. STRONG SUBSIDENCE IS OVER THE CARIBBEAN SEA EXCEPT OVER THE LEEWARD ISLANDS. EXPECT OVER THE NEXT 24 HOURS FOR THE SURFACE TROUGH TO MOVE W AND PRODUCE ADDITIONAL SHOWERS OVER THE W CARIBBEAN AND CENTRAL AMERICA. EXPECT THE CONVECTION OVER THE LEEWARD ISLANDS TO DRIFT OVER PUERTO RICO. ALSO EXPECT THE UPPER LEVEL RIDGE TO EXPAND E AND COVER THE ENTIRE CARIBBEAN SEA. HISPANIOLA... PRESENTLY MOSTLY FAIR WEATHER IS OVER HISPANIOLA. STRONG SUBSIDENCE IS ALSO OVER THE ISLAND. FAIR WEATHER IS EXPECTED TO PERSIST OVER THE NEXT 24 HOURS. ATLANTIC OCEAN... A COLD FRONT IS OVER THE CENTRAL AND WESTERN ATLANTIC FROM 31N50W TO 27N60W TO 27N70W TO S FLORIDA AT 25N80W. SCATTERED SHOWERS ARE WITHIN 120 NM OF THE FRONT. A SURFACE TROUGH IS OVER THE CENTRAL ATLANTIC FROM 31N40W TO 25N45W. SCATTERED SHOWERS ARE WITHIN 120 NM OF THE TROUGH. A 1024 MB HIGH IS CENTERED OVER THE E ATLANTIC NEAR 30N25W. OF NOTE IN THE UPPER LEVELS...AN UPPER LEVEL TROUGH IS N OF 20N BETWEEN 40W-55W ENHANCING THE SHOWERS OVER THE CENTRAL ATLANTIC SURFACE TROUGH. A LARGE UPPER LEVEL LOW IS ALSO CENTERED OVER THE CAPE VERDE ISLANDS NEAR 17N23W ENHANCING CONVECTION OVER W AFRICA. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ FORMOSA