000 AXPZ20 KNHC 062153 TWDEP TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 2205 UTC MON DEC 06 2010 TROPICAL WEATHER DISCUSSION FOR THE EASTERN PACIFIC OCEAN FROM THE EQUATOR TO 32N...EAST OF 140W. BASED ON 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 2100 UTC. ...ITCZ... THE INTERTROPICAL CONVERGENCE ZONE AXIS IS ANALYZED FROM 06N77W TO LOW PRES NEAR 08N115W TO 10N130W THEN RESUMES NEAR 09N133W TO 09N140W. SCATTERED MODERATE TO STRONG CONVECTION IS WITHIN 180 NM OF THE AREA OF LOW PRES IN THE NE AND E QUADRANTS. SCATTERED MODERATE CONVECTION IS WITHIN 45 NM OF THE AXIS BETWEEN 120W AND 126W AND ALSO WITHIN 75 NM N OF THE AXIS W OF 133W. ...DISCUSSION... A NEW COLD FRONT IS APPROACHING THE FAR NW PORTION OF THE AREA. SW WINDS OF 20 TO 25 KT AND SEAS OF 8 TO 13 FT IN NW SWELL EXIST OUT AHEAD OF THE FRONT. THE SOUTHERN PORTION OF THIS FRONT WILL DISSIPATE AS IT ATTEMPTS TO ENTER THE AREA WHILE ENCOUNTERING HIGH PRES WHICH IS PRESENTLY 1026 MB AND LOCATED NEAR 32N122W. THIS HIGH WILL REMAIN NEARLY STATIONARY DURING THE NEXT FEW DAYS. EXPECT SW WINDS TO 20 KT TO PERSIST OVER THE FAR NW CORNER AS YET ANOTHER COLD FRONT APPROACHES FROM THE NW BY 48 HOURS. MEANWHILE LARGE NW SWELL WILL BUILD UP TO 20 FT NEAR 30N140W BY 48 HOURS. AN 1824 UTC ASCAT PASS INDICATED FRESH TRADES BETWEEN THE HIGH CENTER AND A SURFACE TROUGH EXTENDING FROM NEAR 19N127W TO 07N132W. THE TROUGH WILL DISSIPATE WITHIN 24 HOURS ALLOWING FOR WINDS TO DIMINISH TO LESS THAN 20 KT. MEANWHILE 1009 MB LOW PRES IS CENTERED NEAR 08N115W. A 1646 UTC ASCAT PASS CAPTURED 20 TO 25 KT WITHIN 180 NM OF THE LOW CENTER. AN EARLIER JASON ALTIMETER PASS SHOWED SEAS TO 10 FT NEAR THIS SAME AREA OF STRONGEST WINDS. ASSOCIATED CONVECTION IS AS DESCRIBED IN THE ITCZ SECTION ABOVE. THE LOW IS FORECAST TO OPEN UP INTO A TROUGH BY 48 HOURS WITH WINDS DIMINISHING TO 20 KT BY THEN. LATEST MODEL GUIDANCE INDICATES 20 KT NORTHERLY FLOW SETTING UP IN THE NORTHERN PORTION OF THE GULF OF CALIFORNIA BEGINNING AROUND 00 UTC THIS EVENING AS HIGH PRES BUILDS OVER THE GREAT BASIN. THESE WINDS WILL PERSIST THROUGH AT LEAST 18 UTC WED. GAP WINDS... AN EARLIER WINDSAT PASS INDICATED 35 KT WINDS THROUGH THE GULF OF TEHUANTEPEC WITH A MORE RECENT ASCAT PASS INDICATING ASSOCIATED 20 KT WINDS ALL THE WAY DOWNWIND TO 10N102W. MEANWHILE OBSERVATIONS AT LAND BASED STATION IXTEPEC OAXACA MEXICO REPORTED 30 KT WINDS WITH GUSTS TO 40 KT AT 2100 UTC. A SHIP LOCATED NEAR 13N95W REPORTED 21 FT SEAS WHICH IS SIGNIFICANTLY HIGHER THAN GUIDANCE FROM BOTH THE WAVEWATCH AND EUROPEAN WAVE MODELS. EXPECT WINDS TO DIMINISH BELOW GALE FORCE BY 18 UTC TUE ALTHOUGH NE SWELL GENERATED BY THIS EVENT WILL CONTINUE TO PROPAGATE SW REACHING ROUGHLY FROM 05N TO 11N BETWEEN 100W AND 108W BY 18 UTC WED. AN EARLIER ASCAT PASS CAPTURED 20 KT WINDS IN AND DOWNWIND OF THE GULF OF FONSECA. EXPECT THESE WINDS TO DIMINISH TO LESS THAN 20 KT BY 12 UTC TUE. THE SAME ASCAT PASS ALSO SHOWED 20 TO 25 KT WINDS IN THE GULF OF PAPAGAYO DOWNWIND TO NEAR 09N88W. EXPECT THESE WINDS TO PERSIST THROUGH AT LEAST THE NEXT 48 HOURS WITH THE STRONGEST WINDS OCCURRING DURING THE MORNING HOURS DUE TO ENHANCED DRAINAGE FLOW OFF OF CENTRAL AMERICA. 1009 MB LOW PRES IS LOCATED JUST N OF THE ISTHMUS OF PANAMA IN THE FAR SW CARIBBEAN SEA AND THE EARLIER ASCAT PASS ALSO INDICATED 15 KT WINDS IN THE GULF OF PANAMA FLOWING ACROSS THE ISTHMUS ON THE WESTERN SIDE OF THE LOW. MODEL GUIDANCE SUPPORTS INCREASING THE WINDS TO 20 KT IN THE GULF OF PANAMA STARTING AROUND 00 UTC THIS EVENING WITH THE FRESH WINDS THEN PERSISTING THROUGH AT LEAST 48 HOURS. $$ LEWITSKY