000 AXPZ20 KNHC 150338 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 0405 UTC Tue Jan 15 2019 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 0000 UTC surface analysis and satellite imagery through 0230 UTC. ...SPECIAL FEATURES... Gulf of Tehuantepec Gale Warning: Strong high pres N of the region building southward across eastern Mexico continues to support minimal gale force winds across the Gulf of Tehuantepec this evening. Maximum winds are expected to increase to near 40 kt tonight, with associated seas building 14-15 ft. This gale force wind event is expected to continue through Wed morning, with strong northerly winds then continuing across the Gulf through Fri, pulsing to minimal gale force Wed and Thu nights. Winds will then diminishing temporarily Fri night as the high pres weakens and shifts E. NE swell in excess of 8 ft will propagate as far SW as 105W by early Tue morning. This swell will merge with longer period NW and SW swell through the next few days to produce a large area of seas 8 ft and greater well to the south of the Gulf, from 05N to 13N between 93W and 106W. For more information, see the East Pacific High Seas Forecast under WMO/AWIPS headers FZNT02 KNHC/HSFEP2. Looking ahead, a strong gale force to minimal storm force gap wind event is possible at the end of the upcoming weekend into early next week. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The ITCZ extends from 06N90W TO 05.5N99W TO 06.5N125W to beyond 03.5N140W. Scattered moderate isolated strong convection is noted within 180 nm N and 60 nm S of the ITCZ between 113W and 135W. Scattered moderate to strong convection is occurring within 240 nm either side of line from 23N106W TO 17N111W TO 10N118W. ...DISCUSSION... OFFSHORE WATERS WITHIN 250 NM OF MEXICO... A weakening cold front extends from 30N117W TO 20N134W and will stall out across the offshore waters W of Baja California tonight. Moderate to fresh southerly flow ahead of this boundary across the waters north of 27N will diminish tonight as the front weakens. Variable winds less than 15 kt prevail elsewhere across the waters north of 20N. Old long period NW swell of 6 to 8 ft will be reinforcing by new NW swell generated behind the front, and build seas back up to 8 to 11 ft through Tue. Looking ahead, high pressure will build off the west coast of Baja California late this week, allowing fresh to strong northerly winds across the offshore waters north of Cabo San Lazaro. Along with the increasing winds, a new and large set of NW swell will arrive by the end of the week building combined seas up to 10 to 14 ft by Fri night. Gulf of California: Weak high pressure centered in the eastern Pacific off Punta Eugenia this afternoon has collapsed, leaving gentle flow across the Gulf of California north of 25N this evening. The remnants of the high will shift E ahead of an approaching deep layer trough related to the cold front west of the area. This has briefly tightened the pres gradient over the southern Gulf south of 25N, allowing northerly fresh to strong winds between Los Cabos and Cabo Corrientes. Winds will diminish by early Tue as the high pres dissipates. Looking ahead, fresh northerly winds will return to the southern Gulf by late Thu as high pres again builds off the west coast of Baja California. A broad and deep layered upper trough supporting the cold front extends SW into the tropics to near 09N129W. This trough is also supporting an elongated area of moderate to strong convection, extending from near the ITCZ along 120W north northeastward across the Islas Revillagigedo and adjacent offshore waters, and then across extreme Baja California Surf, the southern Gulf of California and into central Sinaloa. This convection described above occurring across the offshore waters and coastal areas will persist through tonight and then begin to diminish on Tue. The NW swell affecting the Baja coastal waters has moved SE today and is peaking at 7-9 ft across the offshore waters of Mexico to the south of 20N and west of 106W. Look for increasing NW swell through tonight across the waters between Cabo Corrientes and Puerto Angel, raising seas to 6-8 ft before subsiding Tue night. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... Gulf of Papagayo: Strong NE to E winds will prevail across the Gulf region. The strongest winds and greatest areal coverage downstream of the Gulf of Papagayo will be each night as nocturnal drainage flow augments the winds. Seas are forecast to build to 8 to 9 ft by early Tue morning. Gulf of Panama: Moderate to fresh northerly winds will flow downstream to near 05N, with pulses to 20 to 25 kt mainly in the SW Gulf off the Azuero Peninsula. Accompanying seas will reach 6 to 8 ft. REMAINDER OF THE AREA... A weakening cold front extends from 30N117W TO 20N134W. This front will weaken and stall out across the offshore waters of Baja California, while a series of additional fronts sweep eastward across the northern waters through the next several days. Expect fresh to strong southerly winds N of 28N ahead of each boundary. Fresh to strong trades just N of the ITCZ across the W central waters will diminish tonight as the supporting pres gradient weakens. These trades will return and expand in coverage by the end of the week as the pres gradient tightens again. Meanwhile, NW swell with seas of 8 ft or greater covers the majority of the waters W of 110W-115W. Highest seas are found in the N portion, ahead of a trough has swept across the far NW corner of the discussion area, where seas are 11 to 15 ft. While this NW swell gradually decays, several reinforcing pulses will propagate SE across the open waters through the end of the week. $$ Stripling