000 AXPZ20 KNHC 270332 TWDEP TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 0405 UTC SUN NOV 27 2011 TROPICAL WEATHER DISCUSSION FOR THE EASTERN PACIFIC OCEAN FROM THE EQUATOR TO 32N...EAST OF 140W. THE FOLLOWING INFORMATION IS BASED ON SATELLITE IMAGERY...WEATHER OBSERVATIONS...RADAR...AND METEOROLOGICAL ANALYSIS. BASED ON 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 0315 UTC. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... THE MONSOON TROUGH EXTENDS SW FROM COSTA RICA AT 10N82W TO 06N94W WHERE LOW LEVEL WINDS INDICATE A TRANSITION TO THE ITCZ WHICH THEN TURNS NW TO 10N99W. THE ITCZ MEANDERS BETWEEN 08N AND 10N THROUGH AN EMBEDDED 1011 MB SURFACE LOW PRESSURE AT 10.5N 117.5W...TO 10N135W WHERE IT TURNS SW AND CONTINUES BEYOND 07N140W. SCATTERED MODERATE ISOLATED STRONG CONVECTION IS NOTED WITHIN 90 NM OF EITHER SIDE OF A LINE FROM 12N113W TO 08N122W. SCATTERED MODERATE CONVECTION ISOLATED IS NOTED WITHIN 30 NM OF THE ITCZ FROM 139W TO 154W. THE REMNANT TROUGH OF KENNETH EXTENDS FROM 11N137W TO 16N134W AND IS EXPECTED TO MOVE W OF 140W EARLY MON. POST FRONTAL HIGH PRESSURE MAINTAINS A GRADIENT OVER THE PACIFIC FROM 11N TO 20N W OF 116W...SUPPORTING NE TO E WINDS 20 KT...WITH SEAS 9 TO 13 FT IN MIXED NE AND NW SWELL. ...DISCUSSION... A LONG WAVE UPPER TROUGH HAS PROGRESSED EASTWARD OVER CENTRAL N AMERICA WITH ITS MEAN AXIS EXTENDING SW INTO THE DISCUSSION AREA FROM TEXAS AT 32N100W THROUGH AN EMBEDDED UPPER CYCLONE OVER THE PACIFIC AT 23N107W...CONTINUING S OVER THE PACIFIC TO A BASE AT 10N110W. A BAND OF DEBRIS MOISTURE PRECEDES THE UPPER TROUGH OVER THE NW GULF OF MEXICO AND FEEDS NE INTO LINES OF CONVECTION MOVING THROUGH THE CENTRAL CONUS. THE ASSOCIATED SURFACE FRONT IS OVER THE NW GULF OF MEXICO AND WILL RACE SE LATE TONIGHT AND SUN RESULTING IN THE STORM WARNING IN...AND DOWNSTREAM OF...THE GULF OF TEHUANTEPEC DISCUSSED BELOW. AN UPPER ANTICYCLONE IS OVER THE DEEP TROPICS AT 11N134W WITH A LONGWAVE RIDGE EXTENDING NE AND COLLAPSING ACROSS THE WESTERN SEABOARD OF N AMERICA. UPPER MOISTURE FROM ITCZ CONVECTION BETWEEN 138W AND 156W...AND FROM OTHER CONVECTION FURTHER W OVER THE CENTRAL TROPICAL PACIFIC...IS ALL ADVECTED NE ALONG THE NW PERIPHERY OF THIS LARGE RIDGE...SPILLING OVER THE RIDGE ACROSS N AMERICA TO THE W OF THE LONGWAVE TROUGH AXIS PREVIOUSLY MENTIONED. AS THE RIDGE COLLAPSES SE A STRONG UPPER TROUGH... CURRENTLY ALONG ABOUT 149W...WILL MOVE E TO THE NW PORTION OF CONUS WITH ITS SOUTHERN EXTENT JUST REACHING THE NW PORTION OF THE DISCUSSION AREA AND STALLING NEAR 32N140W. THE ASSOCIATED SURFACE FRONT WILL STALL FROM 32N135W TO 24N142W ON SUN...THEN RETRACT W AS THE UPPER RIDGE BUILDS N AGAIN CUTTING OFF AN UPPER CYCLONE NEAR 29N142W MON NIGHT INTO TUE. AN UPPER ANTICYCLONE IS NEAR 10N88W WITH A BROAD RIDGE COVERING THE AREA E OF 100W AND EXTENDING NE ACROSS THE SE CONUS. DEBRIS MOISTURE ASSOCIATED WITH THE ITCZ CONVECTION NEAR 10N99W AND BETWEEN 110W AND 125W FANS OUT TO THE N AND S A FEW DEGREES... BUT EVAPORATES IN THE DRY UPPER AIR DOMINATING THE TROPICAL PACIFIC BETWEEN 130W AND 80W. GULF OF CALIFORNIA...NORTHERLY WINDS AT 20 TO 25 KT WILL BECOME N TO NE AT 15 TO 20 KT ON SUN...THEN DIMINISH BELOW 20 KT ON MON. GULF OF TEHUANTEPEC...NORTHERLY WINDS WILL SURGE THROUGH THE CHIVELA PASS AT 15 TO 20 KT AROUND SUNRISE ON SUN...INCREASING RAPIDLY TO STRONG GALE FORCE BY MIDDAY SUN...AND STORM FORCE BY SUNSET SUN. GALE CONDITIONS SHOULD END JUST AFTER SUNRISE ON TUE BUT STRONG N WINDS MAY PERSIST THROUGH THE MIDDLE OF NEXT WEEK. $$ NELSON