000 AXPZ20 KNHC 021621 TWDEP Tropical Weather Discussion...Corrected NWS National Hurricane Center Miami FL 1605 UTC Sat Dec 2 2017 Corrected Remainder of the Area Section 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 1200 UTC surface analysis and satellite imagery through 1545 UTC. ...SPECIAL FEATURES... Gulf of Tehuantepec Gale Warning: The gap wind event of gale force N to NE winds from the past few days diminished to just below gale force during the past hour. These winds are now in the in the 20-30 kt range, and are within 60 nm either side of a line from 16N95W to 15N95W to 12.5N97W with seas of 8 to 11 ft. First few visible satellite images depict low cloud streamers heading to the SW along the eastern and western fringes of the 20-30 kt winds. Seas with these winds are in the 8-12 f range, with the maximum near 15N95W. NE swell induced by the long duration of this event is mixing with longer period NW swell well downstream from the Gulf of Tehuantepec, producing seas of 8-9 ft elsewhere from 10N to 13N between 94W-99W. Model guidance indicates that the northerly winds will gradually diminish to 20 kt or less and seas to less than 8 ft by early Monday afternoon as high pressure N of the area weakens while it shifts eastward. The guidance shows that another gale event is expected to develop late on Wednesday as a strong cold front moves into the Gulf of Mexico and across southern Mexico. INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The Monsoon Trough axis extends from low pressure near 06N78W to 07N87W to 06N97W to 08N106W to 07N115W, where latest scatterometer data indicates it transitions to the Intertropical Convergence Zone (ITCZ) and continues to 11N130W to beyond 09N140W. Scattered moderate isolated convection is within 120 nm S of the axis between 102W-109W. Scattered moderate convection is within 180 nm S of the axis between 109W-114W, and also within 60 nm N of the axis between 78W-80W. ...DISCUSSION... OFFSHORE WATERS WITHIN 250 NM OF MEXICO... An upper level disturbance moving slowly across Baja California Norte this morning will continue eastward into northern Mexico this afternoon. Isolated showers are noted over portions of the northern Gulf of California. This activity is likely to continue into early this afternoon. Weak ridging over the region will support gentle to moderate northerly winds across the area into early next week. Long period NW swell propagating across the waters offshore of Baja California during the past couple of days has reached to near 107W, and is resulting in seas of the range between 8-11 ft across the offshore waters of northern and central Baja California. Seas in the range of are present from Baja California Sur to south of Manzanillo and the Revillagigedo Islands. The swell will slowly decay through Monday allowing for the seas to lower to 8 ft and to below 8 ft by Tuesday afternoon, except for seas remaining at the 6-8 ft range over the offshore waters of northern Baja California. High pressure building in the wake of a cold front moving across the SW U.S. Sunday night through Monday night will induce strong NW winds through the entire length of the Gulf of California Monday and Tuesday. Looking ahead, the high pressure will strengthen through Wednesday, possibly increasing these winds to gale force over the northern Gulf of California late Wednesday, or on Thursday with seas building to a rather high value of around 10 or 11 ft for that portion of the gulf. Please see Special Features section for details about the gale warning in the Gulf of Tehuantepec. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... Gulf of Papagayo: Fresh to strong offshore gap winds across the Papagayo region will peak to 25 kt during the late night and early morning hours through Monday. Seas downstream from the gulf will build to 6-8 ft during the time of peak winds, subsiding slightly each afternoon and evening. Elsewhere, light to gentle N to NE winds are expected north of the monsoon trough and mainly moderate S to SW winds are expected to the south of the monsoon trough. Seas are in the 4-6 ft, but are expected to build to 5-7 ft in a SW swell to the south of the monsoon trough beginning on Sunday afternoon and into Monday. REMAINDER OF THE AREA...Corrected A large area of long period NW swell producing seas of 8-12 ft will continue to propagate across the region west of 110W. The swell will decay to less than 8 ft south of 20N through next week, but persist at 8 ft and greater north of 20N due to reinforcing NW swell entering the region. A rather strong jet stream branch extends in a SW to NE fashion from 28N140W to NE of the area at 32N135W. The associated dynamics is helping to initiate scattered showers and possible isolated thunderstorms within 180 nm to the SE of the jet stream. A cold front NW of the area is connected to a 1013 surface low near 32N140W this morning as a short wave mid-level trough deepens in the central Pacific. This low will deepen tonight and drift generally southward, staying to the west of 140W with associated strong winds. Another mid to upper level disturbance will support the development of a trough near a position from 20N135W to 22N132W by Sunday afternoon. The gradient between the trough and high pressure to the north of the area will result in fresh to strong easterly winds from 20N and 30N between 130W-140W with seas building to 8-11 ft through early next week as the trough slowly moves westward. $$ Aguirre