000 AXPZ20 KNHC 241005 TWDEP TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 1005 UTC WED DEC 24 2008 TROPICAL WEATHER DISCUSSION FOR THE EASTERN PACIFIC OCEAN FROM THE EQUATOR TO 32N...EAST OF 140W. BASED ON 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 0300 UTC. ...ITCZ... ITCZ IS ALONG 05N77W TO 03N81W TO 06N89W TO 05N99W TO 10N115W TO 09N123W TO 11N135W TO 09N140W. SCATTERED MODERATE AND ISOLATED STRONG CONVECTION WILL CONTINUE NEXT 12 HOURS FROM 06N TO 15N BETWEEN 140W AND 120W. SCATTERED MODERATE CONVECTION WILL OCCUR NEXT 12 HOURS WITHIN 200 NM OF 08N115W. ISOLATED MODERATE CONVECTION WILL CONTINUE WITHIN 120 NM OF LINE 12N115W TO 19N109W. ...DISCUSSION... THE BLOCKING UPPER LEVEL PATTERN ACROSS THE FORECAST AREA WILL BREAK DOWN DURING THE NEXT 72 HOURS AS THE DEEP LAYERED CUT OFF LOW ALONG 18.5N146W CONTINUES TO SHIFT W AND GRADUALLY FILL... AND THE DOWNSTREAM RIDGE ACROSS THE EPAC FLATTENS FURTHER... WHICH WILL ALLOW A SHORT WAVE UPPER TROUGH CURRENTLY APPROACHING THE W COAST OF THE U.S. TO CARVE A LONG WAVE TROUGH FROM THE WESTERN U.S. INTO MEXICO AND THEN WEAKLY INTO THE TROPICAL EPAC BY THE UPCOMING WEEKEND. UPPER LEVEL ANTICYCLONIC SHEAR OCCURRING E OF THE DEEP LAYERED CUT OFF LOW CONTINUES TO INTERACT FAVORABLY WITH ABUNDANT MOISTURE FROM THE ITCZ N TO 15N AND BETWEEN 140W AND 120W...TO MAINTAIN A CONVECTIVELY ACTIVE ZONE THERE. THIS ACTIVE WEATHER WILL CONTINUE TO SHIFT W DURING THE NEXT 24 HOURS AS THE DEEP LAYERED LOW MOVES W...ALMOST IN UNISON WITH A FEW PERTURBATIONS MOVING W ALONG THE ITCZ. SW TO NE ALIGNED EASTERLY WAVES WERE ANALYZED ANCHORED ALONG THE ITCZ AT 138W...AND A HIGHER AMPLITUDE WAVE AT 116W. THE SHORT WAVE UPPER TROUGH AND ASSOCIATED VIGOROUS UPPER LOW APPROACHING THE WEST COAST OF THE U.S. IS SUPPORTING A COLD FRONT...AND A 992 MB SURFACE LOW WITH STORM FORCE WINDS IN THE W SEMICIRCLE OF THE LOW. THE FRONT WAS JUST ENTERING THE EXTREME N PORTIONS OF THE FORECAST AREA AT 0900 UTC...WITH GALE FORCE WINDS EXPECTED BEHIND THE FRONT TO SPREAD SOUTHWARD TO 27N DURING THE NEXT 24 HOURS...WITH SEAS THERE BUILDING 10 TO 16 FT IN NW SWELL. SW TO S WINDS WITHIN 120 NM AHEAD OF THE FRONT WILL INCREASE TO AROUND 25 KT AND SHIFT INTO W COASTAL BAJA CALIFORNIA AND THE NORTHERN GULF OF CALIFORNIA BY 36 HOURS. LARGE NW SWELL ASSOCIATED WITH THIS FRONTAL SYSTEM WILL PROPAGATE S AND SE ACROSS THE ENTIRE FORECAST AREA OVER THE NEXT 48 HOURS...WITH 8 FT SEAS EXPECTED TO REACH FROM 20N130W TO THE W CENTRAL COAST OF THE BAJA...AND 12 FT SEAS EXPECTED TO REACH 24N. GAP WINDS HAVE ABATED ACROSS THE GULF OF TEHUANTEPEC DURING THE PAST 24 HOURS. HOWEVER...E TO NE WINDS OF 20 TO 25 KT PERSIST ACROSS AND DOWNSTREAM FROM THE GULF OF PAPAGAYO...AND ARE FORECAST TO INCREASE 20 TO 30 KT BY 24 HOURS. SEAS ACROSS THIS NARROW ZONE WILL INCREASE TO 9 FEET BY 24 HOURS. $$ STRIPLING