000 AXNT20 KNHC 212354 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 805 PM EDT SAT SEP 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 2315 UTC. ...TROPICAL WAVES... TROPICAL WAVE EXTENDS FROM 19N25W TO 12N24W MOVING W AT 10-15 KT. THE WAVE REMAINS EMBEDDED IN A MOIST SSMI TOTAL PRECIPITABLE WATER VAPOR AREA. ISOLATED MODERATE CONVECTION IS WITHIN 120 NM OF THE WAVE AXIS. TROPICAL WAVE EXTENDS FROM 25N38W TO 16N39W MOVING W AT 10-15 KT. TOTAL PRECIPITABLE WATER IMAGERY INDICATES MOST OF THE WAVE HAS FRACTURED AWAY FROM THE MOISTURE-LADEN MONSOON TROUGH REGION AND IS EXPECTED TO BEGIN INTERACTION WITH A FRONTAL TROUGH TO THE NW OVER THE NEXT FEW DAYS. NO SIGNIFICANT DEEP CONVECTION IS NOTED ON SATELLITE IMAGERY AT THIS TIME WITH THE WAVE. ...ITCZ/MONSOON TROUGH... THE MONSOON TROUGH EXTENDS FROM THE AFRICAN COAST NEAR 13N17W TO 12N24W TO A 1010 MB LOW NEAR 13N32W TO 11N42W TO 9N45W. THE INTERTROPICAL CONVERGENCE ZONE AXIS EXTENDS FROM 9N45W TO 10N53W. ISOLATED MODERATE CONVECTION IS FROM 6N-19N BETWEEN 20W- 32W. ...DISCUSSION... GULF OF MEXICO... AS OF 2100 UTC...A COLD FRONT EXTENDS FROM S LOUISIANA AT 30N91W TO A 1004 MB LOW OFF THE COAST OF S TEXAS NEAR 26N96W TO S OF TAMPICO MEXICO AT 20N97W. SCATTERED MODERATE CONVECTION IS FROM 26N-30N BETWEEN 86W-94W... AND FROM 17N-27N BETWEEN 94W-98W. 20- 25 NORTHERLY WINDS ARE N OF THE FRONT OFF THE COAST OF TEXAS. EXPECT THE FRONT IN 24 HOURS TO EXTEND FRON THE FLORIDA PANHADLE TO THE NW GULF OF MEXICO TO THE SOUTHERN BAY OF CAMPECHE... WITH CONTINUED CONVECTION. CARIBBEAN SEA... A LAX SURFACE PRESSURE GRADIENT IS OVER THE CARIBBEAN SEA WITH 10-15 KT WINDS. SCATTERED MODERATE CONVECTION IS OVER THE W CARIBBEAN FROM 12N-21N BETWEEN 79W-83W. SCATTERED MODERATE CONVECTION IS ALSO OVER PUERTO RICO...HISPANIOLA...CUBA...AND JAMAICA. SCATTERED MODERATE TO ISOLATED STRONG CONVECTION IS ALSO INLAND OVER CENTRAL AMERICA FROM PANAMA TO BELIZE. IN THE UPPER LEVELS...THE BASE OF AN UPPER LEVEL TROUGH IS OVER CUBA. UPPER LEVEL DIFFLUENCE IS OVER THE W CARIBBEAN S OF CUBA ENHANCING THE CONVECTION. EXPECT OVER THE NEXT 24 HOURS FOR THE TRADEWINDS TO INCREASE TO 20-25 KT OVER THE CENTRAL CARIBBEAN. EXPECT LITTLE CHANGE IN CONVECTION OVER THE NEXT 24 HOURS. HISPANIOLA... PRESENTLY SCATTERED MODERATE CONVECTION IS OVER HISPANIOLA. EXPECT SIMILAR CONVECTION TOMORROW EVENING DUE TO UPPER LEVEL DIFFLUENCE AND EVENING AIRMASS HEATING. ATLANTIC OCEAN... A SURFACE TROUGH IS OVER THE W ATLANTIC FROM 30N73W TO THE N BAHAMAS AT 25N76W. SCATTERED SHOWERS ARE E OF THE WAVE AXIS FROM 26N-31N BETWEEN 68W-74W. A 1004 MB LOW IS FURTHER E AT 29N62W MOVING N. A SURFACE TROUGH EXTENDS SW FROM THE LOW TO 25N64W TO THE S BAHAMAS AT 22N71W. SCATTERED MODERATE CONVECTION IS E OF THE TROUGH AXIS FROM 20N-26N BETWEEN 58W-63W. A STATIONARY FRONT IS OVER THE CENTRAL ATLANTIC FROM 31N50W TO 30N60W TO THE LOW AT 29N62W. SCATTERED MODERATE CONVECTION IS FROM 29N-32N BETWEEN 55W-59W. A SURFACE TROUGH IS OVER THE E ATLANTIC FROM 32N38W TO 28N45W. ISOLATED MODERATE CONVECTION IS 180 NM E OF THE TROUGH AXIS. OF NOTE IN THE UPPER LEVELS...AN UPPER LEVEL TROUGH IS OVER THE W ATLANTIC W OF 60W. AN UPPER LEVELRIDGE IS OVER THE CENTRAL ATLANTI N OF 25N BETWEEN 40W-60W. A SMALL UPPER LEVEL LOW IS CENTERED OVER THE CENTRAL ATLANTIC AT 20N50W WITH STRONG SUBSIDENCE. A LARGE UPPER LEVEL TROUGH IS OVER THE E ATLANTIC N OF 10N E OF 40W. EXPECT OVER THE NEXT 24 HOURS FOR THE SURFACE FRONT TO PRODUCE CONVECTION OVER THE W ATLANTIC N OF 25N AND W OF 75W. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ FORMOSA