000 AXPZ20 KNHC 092218 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 2205 UTC Wed Jan 9 2019 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 1800 UTC surface analysis and satellite imagery through 2100 UTC. ...SPECIAL FEATURES... Gale Warning: Gale force northerly winds will prevail across the Gulf of Tehunatepec today through early Fri morning before diminishing. Currently, gales extends southward from the coast to near 14N96W, where seas area near 13 ft. Maximum winds with this event are expected tonight around 0600 UTC, when peak winds of 40-45 kt are expected, when seas will build to 12-18 ft. This gap wind event is being driven by strong high pressure building across the western Gulf of Mexico behind a cold front. Winds are forecast to rapidly diminish on Friday as winds in the Gulf of Mexico sharply veer to the south. Please see the latest High Seas Forecast product under AWIPS/WMO headers HSFEP2/FZPN03 KNHC for more details. Gale Warning: A strong cold front is forecast to reach the NW corner of the discussion area near 30N140W by early Thu afternoon, followed by reinforcing large long period NW swell. Gale force winds, likely in the 30-40 kt range, are expected on either side of the front, but mainly N of 28N midday Thu through early Fri. Seas are forecast to build up to 20-22 ft behind the front. Fresh to strong winds will persist on either side of the front through Fri, as it continues eastward, with seas of 12-17 ft in NW swell in the wake of the front. See the latest High Seas Forecast product under AWIPS/WMO headers HSFEP2/FZPN03 KNHC for more details. .INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... A surface trough extends from Colombia near 06N72.5W TO 03N78W TO 08N88W TO 06N93W. The ITCZ continues from 04N97W TO 08N124W TO beyond 07N140W. Scattered moderate convection is noted from 04N to 07N W of 132W. ...DISCUSSION... OFFSHORE WATERS WITHIN 250 NM OF MEXICO... A weak ridge, anchored by a 1022 mb high pressure located near 27N121W, dominates the waters west of Baja California, producing light to moderate N to NE winds across the offshore waters this afternoon. An approaching cold front from the west has slowed its forward motion and extends from near 30N123W to beyond 23N132W, and is associated with a deep low pressure system well north of the area. This system has generated very large NW swell, with morning satellite altimeter data showing seas of 20 to 24 ft from 27N to 30N along 127W. This powerful NW swell has begun to reach the coastline of Baja California Norte and will build across the offshore waters through early Thu morning. Peak seas of 10-15 ft across the northern waters late tonight will reach the southern waters at 8-12 ft on Thu, then slowly subside Thu night through early Sat. In addition to generating high and hazardous seas across the offshore waters, this large long period swell, with a leading edge period of 18 to 20 seconds, will create very high and dangerous surf along the coasts and outer reefs of Baja California Wed night through Thu, and produce very strong rip currents in the surf zone, and localized areas of coastal erosion. Gulf of California: Late morning scatterometer data indicate moderate NW winds over the southern half of the Gulf, while gentle NW winds are assumed to prevail across the far northern portions. Seas are running from 1-2 ft across north portions to 4-5 ft across the south part. Gentle to moderate winds are expected across the Gulf through Fri. Variable winds of 10 kt or less generally prevail across the remaining waters from Las Tres Marias to Puerto Angel, where seas are 4-6 ft in fading NW swell. The large NW swell arriving into Baja waters will reach SW Mexico late Thu afternoon and is expected to peak at 5-9 ft by late Fri. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... Gulf of Papagayo: Fresh NE to E winds will prevail across the Gulf region, and become fresh to strong across and downstream of the Gulf of Papagayo each night through the weekend with the assistance of the nocturnal drainage flow. Gulf of Panama: Moderate to fresh northerly winds downstream to near 05N with seas to 6 ft will continue through the weekend. REMAINDER OF THE AREA... A cold front moving eastward across the north waters extends from 30N123W TO 23N132W TO 20N140W. The front is expected to continue to move slowly and reach near 120W tonight, where it will weaken, meander, and become ill defined between 120W and Baja California Thu. Winds have diminished to 20 kt or less on either side of the front across the forecast waters. However, large seas up to 24 ft in large long period NW swell, associated with this front, will continue to propagate SE across the open waters through Thu, and into the offshore waters of Baja California today through tonight. The next cold front to move into NW portions Thu will bring gale force winds as discussed above. $$ Stripling