000 AXNT20 KNHC 202358 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 805 PM EDT SAT OCT 20 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 2315 UTC. ...SPECIAL FEATURES... TROPICAL WAVE IN THE CARIBBEAN SEA EXTENDS FROM 20N75W TO A 1007 MB LOW AT 15N73W TO 12N72W MOVING W AT 5-10 KT. LOW-LEVEL CYCLONIC FLOW IS EVIDENT ON VISIBLE SATELLITE IMAGERY WITH TOTAL PRECIPITABLE WATER IMAGERY ALSO INDICATING MAXIMUM VALUES OF DEEP LAYER MOISTURE ACROSS THE CENTRAL CARIBBEAN BETWEEN 69W-77W. SCATTERED MODERATE CONVECTION IS N OF THE LOW CENTER FROM 15N-18N BETWEEN 69W-74W TO INCLUDE PORTIONS OF HISPANIOLA. AN UPPER LEVEL ANTICYCLONIC CENTERED IS OVER THIS TROPICAL WAVE. ENVIRONMENTAL CONDITIONS ARE FORECAST TO BECOME MORE FAVORABLE FOR DEVELOPMENT DURING THE NEXT DAY OR TWO AS THE DISTURBANCE MOVES WESTWARD. THIS SYSTEM HAS A HIGH CHANCE OF BECOMING A TROPICAL CYCLONE DURING THE NEXT 48 HOURS. HEAVY RAINS ARE POSSIBLE WITH THIS SYSTEM OVER JAMAICA...EASTERN CUBA...AND HISPANIOLA OVER THE NEXT SEVERAL DAYS. FLASH FLOODING AND MUD SLIDES COULD OCCUR ESPECIALLY NEAR HIGH TERRAIN. TROPICAL WAVE EXTENDS FROM 22N48W TO A 1009 MB LOW AT 17N46W TO 13N42W MOVING W AT 10-15 KT. A 1536 UTC OSCAT IMAGERY DEPICTS THE LOW CENTER WELL. A STRONG WIND FIELD WITH E TO NE WINDS IN THE RANGE OF 20 TO 25 KT...IS WELL N OF THE LOW CENTER. THIS AREA CLOSELY MIRRORS AN AREA OF SCATTERED MODERATE CONVECTION FROM 20N-24N BETWEEN 40W-51W AND IS LIKELY ENHANCED BY UPPER LEVEL DIFFLUENCE DUE TO AN UPPER LEVEL LOW CENTERED NEAR 19N50W. THIS SYSTEM HAS A MEDIUM CHANCE OF BECOMING A TROPICAL CYCLONE DURING THE NEXT 48 HOURS. ...TROPICAL WAVES... TROPICAL WAVE EXTENDS FROM 20N57W TO 14N59W MOVING W AT 10-15 KT. THE WAVE REMAINS DIFFICULT TO DISCERN ON SATELLITE IMAGERY...HOWEVER DOES COINCIDE WITH VERY WEAK LOW-LEVEL CYCLONIC STREAMLINES ON RECENT GLOBAL MODEL DATA ALONG 58W. NO SIGNIFICANT CONVECTION IS NOTED WITH THE WAVE AT THIS TIME. ...ITCZ/MONSOON TROUGH... THE MONSOON TROUGH EXTENDS FROM THE AFRICAN COAST NEAR 13N17W TO 11N20W TO 11N31W TO 8N39W. THE INTERTROPICAL CONVERGENCE ZONE AXIS EXTENDS FROM 8N39W TO THE COAST OF N BRAZIL AT 2N51W. SCATTERED MODERATE TO ISOLATED STRONG CONVECTION IS FROM 6N-13N BETWEEN 16W-29W. WIDELY SCATTERED MODERATE CONVECTION IS FROM 9N-12N BETWEEN 33W-37W...AND FROM 5N-9N BETWEEN 40W-42W. ...DISCUSSION... GULF OF MEXICO... AS OF 2100 UTC...A VERY SHALLOW COLD FRONT EXTENDS FROM S FLORIDA AT 26N80W TO 25N82W. A DISSIPATING COLD FRONT CONTINUES TO N OF THE YUCATAN PENINSULA AT 23N90W. CONVECTION IS WELL SE OF THE FRONT OVER CUBA. 10-15 KT NE TO E WINDS ARE N OF THE FRONT WITH FAIR WEATHER. IN THE UPPER LEVELS...THE BASE OF AN UPPER LEVEL TROUGH IS OVER THE GULF WITH AXIS ALONG 85W. UPPER LEVEL DIFFLUENCE E OF THE TROUGH IS HELPING TO PRODUCE CONVECTION OVER CUBA...AND THE BAHAMAS. EXPECT IN 24 HOURS...FOR HIGH PRESSURE RIDGING AND FAIR WEATHER TO PREVAIL OVER THE GULF WITH COOLER TEMPERATURES. CARIBBEAN SEA... A TROPICAL WAVE IS OVER THE CENTRAL CARIBBEAN SEA. SEE ABOVE. 10-25 KT TRADEWINDS ARE OVER THE CARIBBEAN SEA WITH STRONGEST WINDS S OF HISPANIOLA. A SURFACE TROUGH IS OVER THE W CARIBBEAN SEA FROM 20N86W TO 16N84W TO 12N82W. ISOLATED MODERATE CONVECTION IS OVER THE NW CARIBBEAN FROM 16N-21N BETWEEN 83W-90W. FURTHER S...CLUSTERS OF SCATTERED MODERATE TO ISOLATED STRONG CONVECTION ARE OVER CENTRAL AMERICA FROM PANAMA TO HONDURAS. SIMILAR CONVECTION IS OVER CUBA...AND JAMAICA. CLUSTERS OF WIDELY SCATTERED MODERATE CONVECTION ARE INLAND OVER COLOMBIA AND VENEZUELA. IN THE UPPER LEVELS...AN UPPER LEVEL HIGH IS CENTERED OVER THE CENTRAL CARIBBEAN NEAR 17N72W. CONSIDERABLE UPPER LEVEL MOISTURE AND BROKEN HIGH CLOUDS ARE OVER MOST OF THE CARIBBEAN. EXPECT SHOWERS AND CONVECTION TO CONTINUE TO BE PREVALENT OVER MOST OF THE CENTRAL AND WEST CARIBBEAN W OF 65W OVER THE NEXT 24 HOURS. ATLANTIC OCEAN... AS OF 2100 UTC...A COLD FRONT IS OVER THE W ATLANTIC FROM 32N72W TO 28N75W TO 26N80W. SCATTERED MODERATE CONVECTION IS WITHIN 300 NM E OF THE FRONT OVER THE BAHAMAS AND THE W ATLANTIC. A 1020 MB HIGH IS CENTERED OVER THE CENTRAL ATLANTIC NEAR 30N39W PRODUCING FAIR WEATHER. AN UPPER LEVEL LOW IS CENTERED OVER THE TROPICS AT 19N50W. CONSIDERABLE UPPER LEVEL DIFFLUENCE IS ENHANCING CONVECTION E OF THE CENTER FROM 14N-25N BETWEEN 35W-50W. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ FORMOSA