000 AXPZ20 KNHC 100919 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 919 UTC Sat Mar 10 2018 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 0830 UTC. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... A surface trough extends from 05N78W to 04N90W. The ITCZ axis continues from 04N90W to 03N110W to 02N120W to 05N130W to 07N140W. No significant convection is noted. ...DISCUSSION... OFFSHORE WATERS WITHIN 250 NM OF MEXICO... Nearly stationary 1020 mb high pressure centered near 27N121W ridges SE across the open waters W of the Baja California peninsula. Mainly light to moderate NW-N winds prevail beneath this ridge, except moderate to locally fresh winds adjacent to the Baja California peninsula. These conditions will prevail through today. Winds will increase to between 15 and 20 kt Sun through Tue as the high gradually builds, with the high then weakening by mid-week as a decaying cold front approaches. Winds near Cabo Corrientes could become locally strong tonight through Sun. Gulf of California: Light to gentle winds are expected across the northern Gulf through today, with mainly gentle to moderate winds prevailing across the central and southern waters. Winds will increase to 10-15 kt across the northern Gulf Sun through early next week in response to building high pres just NW of the offshore zones. Winds will become fresh to locally strong across the central and southern waters Sun night and Mon night. The pressure gradient across the region will weaken Tue through Wed allowing for winds to diminish to gentle to moderate across the Gulf of California. Gulf of Tehuantepec: Light to moderate onshore winds will prevail through the weekend. Model guidance suggests another northerly gap wind event commencing Mon as expansive high pressure builds southward over the western Gulf of Mexico behind the next cold front. Winds will rapidly increase to gale force Mon evening, peaking around 40 kt overnight into early Tue. Gale force winds may diminish by early Thu, with brief lulls below gale force also possible during the afternoon hours Tue and Wed. Seas will peak around 16 ft Tue morning. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... The Fuego Volcano located in Guatemala near 14.5N90.9W continues to intermittently vent light amounts of smoke and ash. Any significant ash emissions that do occur will likely remain over land to the west of the summit during the next 12 to 24 hours. High pressure ridging SE over the Caribbean will continue to support pulsing fresh to strong winds over the Gulf of Papagayo, mainly during the overnight and early morning hours, through Sun morning. Winds will peak at around 30 kt in the immediate Gulf, with seas building to 7-8 ft. The ridging will weaken thereafter with pulsing moderate to fresh winds expected Sun night through mid-week. Over the Gulf of Panama, moderate N winds will pulse to fresh through this morning. Seas are expected to be 5-6 ft as N wind waves mix with moderate cross-equatorial SW swell. Elsewhere, expect gentle to moderate winds and 4-7 ft seas to prevail during the next couple of days. REMAINDER OF THE AREA... A rather complex set of surface troughs and broad low pressure is present across the NW portion and N central waters. Weak 1012 mb low pressure is along a trough, centered near 29.5N128.5W, moving NE. Deep tropical moisture extends from across the Hawaiian Islands into the discussion waters, with scattered moderate and isolated strong convection within an area bounded by 30N134W to 30N120W to 20N130W to 15N140W to 26N140W to 30N134W. Recent scatterometer data showed 20-30 kt winds within 120 nm in the SE semicircle of the low, with 20-25 kt winds also likely W of the trough and low to 130W. Seas are up to 8 ft near the area of strongest winds. These conditions will lift N of the area by this evening. The next cold front will breach 30N140W from the NW by Sun afternoon. An area of fresh to strong SW winds will precede the front, as well as follow it, diminishing by Mon night. Large NW swell will also accompany the boundary reaching up to 14-16 ft by Mon evening. The front will weaken as it moves across the NW portion, then a weaker cold front will introduce a round of reinforcing NW swell Tue night through Wed night. Moderate to locally fresh trades combined with decaying NW swell is supporting combined seas of 7-9 ft across the W central waters to the N of the convergence zone to 15N. The pressure gradient will weaken this weekend allowing for the seas to subside to less than 8 ft by early next week. $$ Lewitsky