000 AXPZ20 KNHC 211512 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 1505 UTC Thu Dec 21 2017 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 1400 UTC. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough extends from 05N77W to 06N95W to 08N104W where the ITCZ begins and continues to 10N115W to 10N125W to beyond 06N140W. Numerous moderate and isolated strong convection are from 10N to 18N between 109W and 116W. Scattered moderate convection is from 03N to 07N E of 81W and from 07N to 16N between 116W and 127W. ...DISCUSSION... OFFSHORE WATERS WITHIN 250 NM OF MEXICO... Gulf of California: A cold front is crossing Baja California and the gulf, currently extending from 32N112W to 28N120W to 30N130W. Fresh to strong NW winds are occurring behind the front. These winds will continue to spread south over the Gulf through tonight, reaching as far S as San Jose del Cabo Friday night. Peak wave heights should reach up to 8 ft on Friday in the central Gulf. Some fresh to briefly strong winds will emerge over the Pacific coast of Baja California in the gaps between the highest terrain. Conditions will improve through Sunday with generally benign conditions thereafter through Tuesday. Gulf of Tehuantepec: Fresh winds over the Gulf will diminish through late morning. A new Tehuantepec gap wind event should occur starting early Sunday, due to a strong cold front pushing across the Gulf of Mexico. Model consensus indicates winds will increase to 20 to 30 kt early Sunday morning, with gale force winds beginning late Sunday night, and continuing through Tuesday afternoon. Winds should peak before daybreak Monday and again Tuesday morning between 35-40 kt. 12 ft seas or greater are likely to occur on Monday and Tuesday in the Gulf with maximum seas around 15 ft early Tuesday. NW near gale winds just offshore of southern California and fresh winds west of Baja California Norte will produce combined seas with embedded NW swell west of Baja California Norte of 8 to 9 ft through tonight. Elsewhere winds are fresh breeze or weaker with seas less than 8 ft. These conditions will prevail through Tuesday. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... Fresh to strong NE winds are likely occurring near the Gulf of Papagayo this morning. These winds will diminish slightly Friday through Saturday night before returning Sunday through at least Tuesday. Seas should remain under 8 ft through Sunday, and peak near 8 ft Sunday, Monday, and Tuesday nights. NE swell to 9 ft will clip the western offshore waters of Guatemala Monday and Tuesday due to the Gulf of Tehuantepec gap wind event. Elsewhere winds are fresh breeze or weaker with seas less than 8 ft. These conditions will prevail through Tuesday. REMAINDER OF THE AREA... Mainly Moderate to fresh east to northeast winds prevail over the waters from the ITCZ to 30N, driven by high pressure centered north of the region. These winds support 6 to 8 ft seas in a NW swell. Winds become northerly N of 25N and E of 125W as a cold front crosses this region. Seas behind the front N of 27N are building to 7 to 9 ft and will continue over these waters through early Friday morning. To the south of the ITCZ, gentle to moderate SE winds prevail with seas of 5 to 7 ft. High pressure will build SE toward California on Friday while low pressure currently developing west of our waters just east of Hawaii tracks NE. The pressure gradient between these two features will support fresh to strong SE winds north of 20N and west of 135W beginning Friday. Models have trended slightly stronger with this system since yesterday, with SE to S winds of 20 to 30 kt now expected late Friday night through Saturday N of 24N and W of 133W, as the low clips the corner of our area of discussion near 30N140W. Seas of 8 to 15 ft are expected during this time period over these affected waters. The low will lift well to the north of 30N Saturday night with improving winds over our waters. NW swell of 8 to 10 ft will continue to propagate away from the departing system Sunday through Monday, reaching as far SE as 10N and as far east as 125W by Monday night, before the swell begins to decay below 8 ft. $$ Latto