000 AXPZ20 KNHC 010911 TWDEP TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 1005 UTC SAT JAN 01 2011 TROPICAL WEATHER DISCUSSION FOR THE EASTERN PACIFIC OCEAN FROM THE EQUATOR TO 32N...EAST OF 140W. BASED ON 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 0715 UTC. ...ITCZ... THE INTERTROPICAL CONVERGENCE ZONE IS ANALYZED FROM 1009 MB LOW PRES NEAR 06N81W TO 04N87W TO 06N95W TO 09N120W TO 07N140W. SCATTERED MODERATE CONVECTION WAS WITHIN 45 NM EITHER SIDE OF THE ITCZ AXIS BETWEEN 121W AND 128W. ...DISCUSSION... THE UPPER TROUGH CURRENTLY CENTERED OVER THE CENTRAL U.S. THROUGH NORTHERN MEXICO INTO N WATERS IS BEING REINFORCED BY A SYSTEM WELL N OF THE AREA THAT IS BEGINNING TO DROP INTO THE BACKSIDE OF THE TROUGH OFF THE CALIFORNIA COAST...BROADENING THE TROUGHING OVER N WATERS. A 150 KT UPPER JET IS FOUND ON THE LEADING EDGE OF THIS TROUGH AND THE REAR RIGHT QUADRANT OF THIS JET IS RESPONSIBLE FOR UPPER LEVEL DIFFLUENCE NEAR THE CENTRAL MEXICAN COAST THAT IS ENHANCING THE SCATTERED MODERATE CONVECTION FOUND FROM 11N TO 16N BETWEEN 103W AND 112W. THE REINFORCING SYSTEM MOVING INTO THIS TROUGH IS REFLECTED AS A 995 MB SURFACE LOW NEAR 44N134W ON THE 0600 UTC SURFACE ANALYSIS AND IS FORECAST TO DRAG A COLD FRONT SOUTHEASTWARD THROUGH NE WATERS TONIGHT AND SUN BEFORE DISSIPATING. WINDS WILL REMAIN UNDER 20 KT WITHIN THIS SYSTEM S OF 30N. 14 TO 16 SECOND PERIOD NW SWELL ASSOCIATED WITH THE SYSTEM IS NOT FORECAST TO REACH N WATERS UNTIL SUN AND WILL RAISE WAVE HEIGHTS AS HIGH AS 13 FT SUN NIGHT. 1022 MB HIGH PRES CURRENTLY RESIDES NEAR 27N124W. THE PRES GRADIENT BETWEEN THIS HIGH AND LOWER PRES ALONG THE ITCZ IS RESPONSIBLE FOR AN AREA OF FRESH TRADE WINDS W OF 125W FROM JUST N OF THE ITCZ TO 12N. BY SAT NIGHT...HIGH PRES W OF THE AFOREMENTIONED COLD FRONT WILL BECOME THE DOMINANT RIDGE CENTER AND FRESH TRADES WILL EXPAND E TO 115W AS THE FORMER HIGH CENTER MOVES E AND WEAKENS. CURRENTLY...THE PRES GRADIENT BETWEEN THIS 1022 MB HIGH AND LOWER PRES OVER N CENTRAL MEXICO IS GENERATING FRESH NW TO N WINDS ALONG THE W COAST OF BAJA CALIFORNIA SUR. SHIP ZCDF4 REPORTED 20 KT N WINDS NEAR 25N113W AT 0600 UTC AND SHIP 9HJB9 REPORTED 22 KT WINDS NEAR 23N11W AT 0400 UTC. SEAS ARE AS HIGH AS 8 FT NEAR THE COAST HERE IN NW SWELL. WINDS HERE ARE EXPECTED TO DIMINISH BELOW 20 KT THIS MORNING AS THIS HIGH PRES WEAKENS AHEAD OF THE COLD FRONT MOVING INTO N WATERS AND THE TROUGHING OVER THE CENTRAL U.S. AND MEXICO PUSHES EASTWARD. FRESH NW TO N WINDS ARE EXPECTED IN THE GULF OF CALIFORNIA BY SAT AFTERNOON AS HIGH PRES BUILDS OVER THE U.S. GREAT BASIN BEHIND THE DEEP LAYER TROUGH AXIS AND INCREASES THE PRES GRADIENT OVER THE GULF OF CALIFORNIA BETWEEN THIS HIGH PRES AND TROUGHING OVER THE EASTERN SHORE OF THE GULF ON THE LEE SIDE OF THE SIERRA MADRE OCCIDENTAL. GAP WINDS... N TO NE WINDS THROUGH THE GULF OF PAPAGAYO ARE EXPECTED TO PULSE TO 20 KT THROUGH THE FORECAST PERIOD AS TRADE WINDS FROM THE WESTERN CARIBBEAN BLEED THROUGH CENTRAL AMERICA AND ARE ENHANCED BY MORNING MOUNTAIN DRAINAGE FLOW...MAKING THE EARLY MORNING HOURS THE MOST LIKELY TIME TO SEE THE STRONGEST WINDS. NORTHERLY WINDS ARE EXPECTED TO BEGIN FILTERING THROUGH THE CHIVELA PASS INTO THE GULF OF TEHUANTEPEC BY SUN MORNING AS THE COLD FRONT ASSOCIATED WITH THE DEEP LAYER TROUGHING OVER THE CENTRAL U.S. SWEEPS ACROSS THE WESTERN GULF OF MEXICO. THIS EVENT WILL INTRODUCE N WINDS INITIALLY IN THE 20-25 KT RANGE AND INCREASING TO 30 KT BY VERY EARLY MON. SOME OF THE FORECAST MODELS SHOW WINDS VERY BRIEFLY REACHING GALE FORCE BEFORE SUNRISE MON. $$ SCHAUER