000 AXPZ20 KNHC 060917 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 625 UTC Tue Feb 6 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 0845 UTC. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... A surface trough extends from 09N74W to 05N77W to 07N83W to 06N90W. The ITCZ continues from 06N90W to 05N100W to 06N110W to 06N118W to 09N123W to 10N130W to beyond 08.5N140W. Scattered moderate convection is observed from 07N to 10N between 134W and 138W. A surface trough reaches from 13N123W to 22N123W. This trough is the surface reflection of a mid to upper-level low centered near 24N129W. Numerous moderate and scattered strong convection is observed within 30 nm either side of a line from 13N119W to 16N116.5W. Scattered moderate and isolated strong convection is noted elsewhere from 12N to 18N between 115W and 122W. ...DISCUSSION... OFFSHORE WATERS WITHIN 250 NM OF MEXICO... A 1029 mb high pressure center remains located over the NE Pacific near 42N132W. A weak and elongated ridge extends SE from the high into the offshore waters to SE of the Revillagigedo Islands. The pressure gradient along and offshore of the Baja California peninsula is producing gentle to moderate NW winds this evening, with seas generally running 3 to 5 ft. This fairly quiet pattern should persist through Wednesday. Long period NW swell will cause seas to build to 5-7 ft along the offshore waters N of 20N Tue and Wed. Seas in this region will then begin to subside on Thu. Light to gentle winds and 3 to 5 ft seas will prevail along the Pacific coast of Baja Fri and Sat. Gulf of California: Light to gentle winds and 1 to 3 ft seas will generally prevail through Wednesday. A modest increase in NW winds during mid week will cause seas to build to 3-4 ft, possibly as high as 5 ft Wed evening through Thursday. A low pressure trough will develop over the Baja Peninsula on Fri and Sat. S to SW winds over the Gulf of California E of the trough could become strong on Sat in advance of an approaching cold front. Gulf of Tehuantepec: Strong N winds currently pulsing over the Gulf will taper to light and variable by Tue evening. The pressure gradient over the Isthmus of Tehuantepec will tighten by early Thu as high pres builds southward along the Sierra Madre Oriental mountains of Mexico, while a cold front enters the NW Gulf of Mexico. Another gale force gap wind event should commence over the Gulf of Tehuantepec Thu evening through Fri night as this pattern evolves. This event will peak on Fri morning with seas as high as 14 ft and produce an area of 8 ft seas that will merge with the area of 8 ft seas propagating downwind from the Gulf of Papagayo. The merged area will spread as far S as 06N and as far W as 103W. Winds over the Gulf will decrease once again to light and variable by Sat night. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... Fuego Volcano in Guatemala: Intermittent expulsions of volcanic ash from the volcano have been occurring during the past several days. A plume of ash extending WNW about 75 nm over land from the summit of the volcano to the Chiapas border of Mexico was forecasted yesterday evening, but the latest advisory from the Washington VAAC does not anticipate any further emissions from the volcano during the next 24 hours. No lingering ash is currently evident in satellite imagery. Nocturnal winds will pulse to between fresh and strong speeds each night over the Gulf of Papagayo through the week. Areal coverage of gap winds near the Gulf of Papagayo will increase Thu and Fri. This will allow the wind generated seas of 8 ft to propagate further downwind from the Gulf of Papagayo and merge with the area of 8 ft seas downwind from the Gulf of Tehuantepec on Fri and Sat. Areal coverage of the strong winds will decrease on Sun and Mon. Elsewhere N of 09N, gentle to moderate offshore flow will prevail. Moderate to fresh winds will pulse to strong during overnight hours in the Gulf of Panama as well through Wed morning, becoming moderate to fresh Thu and Fri. Otherwise, light to gentle S to SW winds will generally prevail S of 09N through Fri night. REMAINDER OF THE AREA... The ridge of high pressure mentioned above also extends S across the NW part of the discussion area this morning, and will remain in place during the next several days. NW swell generated by a fetch of winds to the W of a nearly stationary frontal boundary currently NW of the Hawaiian Islands has spread across the W portion of the discussion area and is generating seas of 8 to 9 ft W of a line from 30N128W to 18N129W to 05N140W. The NW swell have peaked and will continue to propagate SE and decay. This will allow the associated area of seas to subside below 8 ft by tonight. A residual area of 8 ft seas will linger from 07N to 15N between 115W and 121W Wed evening. The next significant pulse of NW swell is not expected to enter the area waters until Sat night. Weather for the remainder of the week looks benign with only light to moderate winds and 4-7 ft seas anticipated beyond 250 nm offshore. A persistent surface trough currently extending from 13N123W to 22N123W is producing active convection along and mainly E of the trough axis, as described above. The surface trough is supported by a broad upper-level cyclone centered near 24N129W. The trough will remain near its current location and eventually dissipate by Sat as the mid to upper-level low to the NW weakens and the associated convection gradually diminishes in coverage. $$ CAM