000 AXNT20 KNHC 202330 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 805 PM EDT FRI SEP 20 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 2315 UTC. ...TROPICAL WAVES... TROPICAL WAVE JUST OFF THE COAST OF WESTERN AFRICA EXTENDS FROM 17N19W TO 10N18W MOVING W AT 10-15 KT. SSMI TOTAL PRECIPITABLE WATER IMAGERY SHOWS A LARGE MOIST AREA. SCATTERED SHOWERS ARE WITHIN 120 NM OF THE WAVE AXIS. TROPICAL WAVE EXTENDS FROM 25N35W TO 16N35W MOVING WNW AT 10-15 KT. TOTAL PRECIPITABLE WATER IMAGERY INDICATES MOST OF THE WAVE HAS BEEN UNDERCUT BY A RELATIVELY DRIER AIRMASS WHICH CONTINUES TO LIMIT CONVECTION AT THIS TIME. ISOLATED MODERATE CONVECTION IS FROM 21N-23N BETWEEN 34W-36W. ...ITCZ/MONSOON TROUGH... THE MONSOON TROUGH EXTENDS FROM THE AFRICAN COAST NEAR 13N17W TO 12N20W TO 12N28W TO A 1011 MB LOW NEAR 11N31W TO 8N35W TO 7N40W. THE INTERTROPICAL CONVERGENCE ZONE AXIS EXTENDS FROM 7N40W TO THE COAST OF SOUTH AMERICA AT 3N51W. SCATTERED MODERATE CONVECTION IS FROM 5N-11N BETWEEN 22W-32W...AND FROM 3N-8N BETWEEN 35W-43W. ...DISCUSSION... GULF OF MEXICO... A 1005 MB SURFACE LOW IS CENTERED OVER THE W GULF OF MEXICO NEAR 23N97W MOSTLY VOID OF CONVECTION AND MOVING N. A COLD FRONT IS INLAND OVER N MEXICO AND CENTRAL TEXAS MOVING SE. PREFRONTAL SCATTERED MODERATE TO ISOLATED STRONG CONVECTION IS OVER SE TEXAS...LOUISIANA...AND THE NW GULF OF MEXICO N OF 28N BETWEEN 89W-99W. ELSEWHERE SCATTERED MODERATE CONVECTION IS OVER THE YUCATAN PENINSULA. MOSTLY FAIR WEATHER IS OVER THE REMAINDER OF THE GULF. IN THE UPPER LEVELS...AN UPPER LEVEL HIGH IS CENTERED OVER N MEXICO NEAR 25N100W PRODUCING NORTHERLY UPPER LEVEL WINDS OVER THE GULF. EXPECT THE COLD FRONT TO BE ON THE TEXAS COAST IN 24 HOURS WITH THE SURFACE LOW EMBEDDED ON THE FRONT NEAR BROWNSVILLE TEXAS. ALSO EXPECT CONVECTION OVER THE W GULF W OF 90W. CARIBBEAN SEA... 10-215 KT TRADEWINDS ARE OVER THE CARIBBEAN SEA WITH STRONGEST WINDS OVER THE NW CARIBBEAN. CLUSTERS OF SCATTERED MODERATE TO ISOLATED STRONG CONVECTION DOTS THE CENTRAL AND W CARIBBEAN W OF 70W TO INCLUDE HISPANIOLA...JAMAICA...E CUBA...AND THE CAYMAN ISLANDS. A MONSOON TROUGH EXTENDS INLAND FROM E PANAMA TO W NICARAGUA. AGAIN CLUSTERS OF SCATTERED MODERATE TO ISOLATED STRONG CONVECTION DOTS CENTRAL AMERICA. IN THE UPPER LEVELS...UPPER LEVEL RIDGING IS OVER THE WESTERN AND CENTRAL CARIBBEAN W OF 70W. UPPER LEVEL DIFFLUENCE IS ESPECIALLY NOTED OVER HISPANIOLA ENHANCING CONVECTION. A SMALL UPPER LEVEL LOW IS CENTERED OVER THE E CARIBBEAN NEAR 15N65W. UPPER LEVEL DIFLUENCE E OF THIS CENTER IS PRODUCING SCATTERED SHOWERS OVER PUERTO RICO AND THE E CARIBBEAN E OF 65W. EXPECT LITTLE CHANGE OVER THE NEXT 24 HOURS. HISPANIOLA... SCATTERED MODERATE TO ISOLATED STRONG CONVECTION IS PRESENTLY OVER HISPANIOLA. THIS CONVECTION IS DUE TO BOTH AFTERNOON HEATING AND UPPER LEVEL DIFFLUENCE. EXPECT SIMILAR CONVECTION TOMORROW EVENING. ATLANTIC OCEAN... A 1009 MB LOW IS OVER THE W ATLANTIC NEAR 28N63W. A SURFACE TROUGH EXTENDS SW FROM THE LOW TO THE S BAHAMAS ALONG 23N70W 22N77W. A STATIONARY FRONT IS OVER THE CENTRAL ATLANTIC FROM 32N45W TO 30N50W TO 29N60W TO THE LOW AT 28N63W. SCATTERED MODERATE CONVECTION IS S OF THE SYSTEM FROM 20N-25N BETWEEN 63W- 68W... AND FROM 23N-30N BETWEEN 56W-63W. SCATTERED SHOWERS ARE ALSO OVER THE SOUTHERN BAHAMAS. A 1-15 MB HIGH IS OVER THE CENTRAL ATLANTIC NEAR 23N44W. IN THE TROPICS...A 1011 MB LOW IS E OF THE LESSER ANTILLES NEAR 15N55W MOVING W. A SURFACE TROUGH EXTENDS FROM 18N53W TO THE LOW TO 11N57W. SCATTERED SHOWERS ARE WITHIN 120 NM OF THE TROUGH AXIS. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ FORMOSA