000 AXPZ20 KNHC 030948 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 1005 UTC Thu Jan 3 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 0600 UTC surface analysis and satellite imagery through 0900 UTC. ...SPECIAL FEATURES... ...Gale Warning... A cold front is expected to move across the western Gulf of Mexico Thu and reach the Bay of Campeche early Fri. Winds behind the front will funnel into the Gulf of Tehuantepec Fri morning, increasing to gale force Fri afternoon through Sat morning. .INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... A surface trough extends from 09.5N75W TO 03N79W TO 05N82W TO 04.5N88W. The ITCZ extends from 04.5N88W TO 08N111W TO 09N124W TO 05N132W to beyond 07N140W. Scattered to locally numerous moderate to strong convection was noted from 05N to 12N between 104W and 133W. Widely scattered moderate isolated strong convection was noted elsewhere from 04N to 17N between 113W and 138W. ...DISCUSSION... OFFSHORE WATERS WITHIN 250 NM OF MEXICO... High pressure centered to the NW of the area extends a ridge SE to near Las Tres Marias. A cold front has dissipated tonight across the area from NW Mexico across Baja California Sur to near 25N126W. Fresh to locally strong N to NE winds prevail across the offshore waters of Baja California tonight with slowly subsiding seas of 5-7 ft in NW swell. Winds and seas will diminish very modestly through early Fri. Gulf of California: High pressure across the Great Basin region will support fresh to strong NW winds across the full length of the Gulf of California through Thu morning then will slowly diminish through Fri morning. Strong northerly winds will spill through the mountain gaps of the Baja Peninsula to produce narrow zones of strong and gusty NE winds across the offshore Pacific waters of Baja California. Gulf of Tehuantepec: Fresh northerly gap winds will prevail across the near shore waters of the Gulf tonight through Thu morning before becoming light and variable Thu afternoon. North winds will then return Thu night and increase to 20-30 kt by Fri morning as a cold front approaches the region from the north. Gales are expected to commence by Fri afternoon, as discussed above. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... Strong NE to E winds are expected across and downstream of the Gulf of Papagayo through Fri. Fresh to strong offshore winds are expected elsewhere from El Salvador to Panama through Fri. Moderate to fresh N winds will prevail across the Gulf of Panama through Thu, pulsing to strong during the overnight hours. Elsewhere, gentle to moderate southerly winds are expected S of 08N. REMAINDER OF THE AREA... The pressure gradient between high pressure N of the area and lower pressure in the vicinity of the ITCZ is maintaining a broad area of fresh to strong tradewinds N of the ITCZ to near 25N and W of 112W. This area of high pressure will remain in place N of the area helping to maintain this broad area of fresh to strong trades. Long period NW swell is merging with this tradewind swell to produce seas of 8 to 12 ft over much of the area north of the ITCZ west of 120W. A cold-core upper low will continue digging southward into the base of a mid/upper level trough along about 135W overnight through Fri. This will support the development of a sharp surface trough and eventually weak low pressure along the ITCZ between 120W and 135W today. The resultant tightened pressure gradient will enhance trade winds north of the ITCZ and west of 120W, with near gale conditions possible developing north of the surface trough and low to near 16N. Active convection will prevail north of the ITCZ across this area today through Thu night. This low pressure center and associated moisture will move northward through Fri and then weaken quickly as it veers northeastward, and affect Baja California Sur and the adjacent waters with fresh SW winds and occasional showers through the weekend. $$ Stripling