000 AXPZ20 KNHC 110920 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 1005 UTC Sat Nov 11 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 0600 UTC surface analysis and satellite imagery through 0900 UTC. ...SPECIAL FEATURES... A gale warning remains in effect for the Gulf of Tehuantepec. A tight pressure gradient continues over southeastern Mexico, and model guidance suggests that the current synoptic pattern will remain favorable for northerly gap wind flow to reach gale force the next few days. Winds are expected to increase to 35-40 kt by Sunday night and continue through early next week. Seas are 10- 13 ft in the current conditions, but with the long duration and intensity of these winds, seas build to a maximum of around 17 ft on Tuesday. The leading edge of 8 ft seas propagating away from the source region is forecast to reach 08N100W on Tuesday. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough axis extends westward from Panama near 08N78W to 09N85W to 07N101W to 12N114W through a pair of lows near 11N 116.5W and 09N122W to 08N126W to 10N134W to 09N140W. A large area of showers with clusters of embedded deep convection is from 08N to 16N between 115W and 138W. ...DISCUSSION... OFFSHORE WATERS WITHIN 250 NM OF MEXICO... Please see the special features section for information about the ongoing Gulf of Tehuantepec gale warning. A ridge will dominate the waters W of Baja California during the next several days, while a trough will meander along the coast of NW Mexico and into the Gulf of California. Moderate to fresh NW flow will prevail across the waters W of Baja California from through early Monday. The pressure gradient W of Baja California will tighten Sun night and Mon as high pressure builds eastward. Expect fresh to locally strong NW winds N of 25N and E of 119W from early Monday to early Tuesday, with seas building to around 9 ft. Long period NW swell producing 8-10 ft seas will propagate southeastward across the waters W of Baja California and slowly subside through Sunday. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... Light variable winds, and seas of 4-6 ft, are expected N of 09N, while moderate to locally fresh southerly winds and seas of 5-7 ft are forecast S of 09N through early next week. REMAINDER OF THE AREA... Long period NW swell will propagate southeastward reaching to an area roughly defined from 08N-20N between 114W-131W and from 12N- 20N W of 131W by Sunday afternoon and from 12N-20N W of 124W by Monday afternoon. Consensus global model guidance indicates a late season tropical low pressure system likely to develop along the monsoon trough near 13N125W Sun, then move west-northwest and deepen through Tue. The guidance indicates the pressure gradient between this low and high pressure ridging to the north will create a swath of 20-30 kt winds within about 120-150 nm of the low except in the SW quadrant with associated seas of 9-12 ft, increasing to 12-16 ft by Tue. Upper level winds are expected to become more favorable Sun night through Tue night as vertical shear effects diminish. $$ Mundell