000 AXPZ20 KNHC 222129 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 2022 UTC Mon Jan 22 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 1800 UTC surface analysis and satellite imagery through 2030 UTC. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... A surface trough extends from 07N77W to 05N85W to 07N104W. The ITCZ continues from 07N104W to 09N133W to beyond 09N140W. Scattered moderate and isolated strong convection is present from 04N to 07N between 77W and 85W, from 04N to 06N between 86W and 92W and from 11N to 13N between 113W and 118W. Scattered moderate convection is found from 08N to 10N between 120W and 140W. ...DISCUSSION... OFFSHORE WATERS WITHIN 250 NM OF MEXICO... Gulf of Tehuantepec: For the moment, winds over the Gulf are light and variable. However, strong winds will develop around 06Z tonight, then increase to gale force around 00Z Wednesday. Model guidance has been trending upward with respect to the strength and duration of winds over the Gulf of Tehuantepec during this gap wind event. Latest GFS model run suggests strength of ridging along the Sierra Madre Oriental of Mexico will be stronger than forecast earlier. Based on this have forecasted a continuous period of sustained gale force winds over the Gulf from 00Z Wed to around 12Z Fri. Winds should peak around 06Z Thu with corresponding maximum seas of 15 ft. Propagating N to NE swell will cause seas to build to 8 ft or above as far S as 06N and as far W as 110W on Fri morning; perhaps merging with the larger area of seas to the W associated with long period NW swell. Strong winds over the Gulf should diminish Sat evening as high pres centered over the SE United States shifts E into the western Atlc. Gulf of California: Fresh to strong winds are expected across the central and southern portions of the Gulf through Tuesday before diminishing by Wed evening as Great Basin high pres is weakened by low pres moving into the NW United States. Winds will increase once again this weekend as high pressure rebuild to the lee of the low over the western United States. Decaying NW swell are still maintaining seas in the 8 to 10 ft range off the coast of the Baja California Peninsula. This large swell is producing high surf along the coasts and outer reefs of Baja California and mainland Mexico. While the area of seas greater than 8 ft will slowly subside during the next couple of days, the area is so large that it will take until Thu for dispersion of swell energy to cause the the area to retreat westward to 120W. Before this area of seas can completely decay, a fresh set of NW swell will propagate into the waters off the coast of Baja California Norte Thu night. Seas associated with this swell will peak near 13 ft Friday. Meanwhile, fresh to strong NW winds could visit the far NW waters of Baja California Norte late this week as high pressure builds east toward the region. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... Nocturnal winds will pulse to fresh over the Gulf of Papagayo tonight and will then pulse to strong each night Tuesday night through Thursday night as high pres ridges SE from the Gulf of Mexico over the NW Caribbean. Elsewhere N of 09N, light to gentle offshore flow will prevail. Gentle southerly winds will prevail S of 09N for the next few days. REMAINDER OF THE AREA... High pressure of 1031 mb is centered just north of the area near 32N130W. The pressure gradient between this area of high pressure and lower pressure in the vicinity of the ITCZ is supporting fresh to strong winds from 08N to 25N and west of 115W with peak seas of 13 ft. Combined seas of 12 ft or greater will continue to prevail within this region of strong trade winds, in a mix of dominant long period NW swell and short period NE wind waves. Seas 8 ft or greater cover nearly all the the open waters N of 06N and west of 106W. The area of fresh to strong trades prevailing north of the ITCZ will gradually erode westward during the next couple of days as high pres N of the forecast waters is weakened by low pres moving E into the NW United States. Areal coverage of the fresh to strong trades and seas 12 ft or greater will shrink and shift to the W of 140W by Wed evening as the area of high pressure weakens and the cold front associated with the low approaches the NW waters. High pressure building back in behind the cold front will once again cause the coverage of the fresh to strong trades to increase Thu through Fri night. $$ CAM