000 AXPZ20 KNHC 192149 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 2205 UTC Mon Mar 19 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. ...SPECIAL FEATURES... Gale Warning: A cold front along a position from 30N131W to 21N140W is preceded by strong southerly flow north of 24N and within 240 nm to its east, along with seas of 8 to 11 ft. A deepening surface low pres system currently northwest of the area will drop southeastward tonight behind this initial cold front dragging a second cold front into the discussion area accompanied by a strong to near gale southwest-west-northwest wind shift. The pressure gradient will tighten around the southwest semicircle of the low increasing the westerly winds to minimal gale force winds in the range of 30 to 35 kt over the discussion waters west of the front near 0900 UTC on Tue, with associated seas of 15 to 16 ft. The low pres will lift north of the area on Tue afternoon and winds will diminishing to 20 kt to 30 kt, and to 20 kt or less late Tue night. The associated NW swell, in the form of 8 to 9 ft seas will propagate southeastward through the waters covering the area west of a line from the northern Baja peninsula to 07N129W early on Sat. Please refer to the Pacific high seas forecast for more details on this upcoming event under AWIPS/WMO headers MIAHSFEP2/FZPN03 ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... A surface trough extends from 08N83W to 04N90W to 05N103W where the ITCZ axis begins and continues along 05N103W to 06N120W to 06N140W. Scattered moderate isolated strong convection is noted from 05N to 09N between 108W and 125W. ...DISCUSSION... OFFSHORE WATERS WITHIN 250 NM OF MEXICO... Surface high pressure of 1020 mb west of the northern Baja Peninsula extends a ridge axis S to near 19N. This ridge will shift slightly to the southeast through Tue, thus supporting fresh to locally strong northerly winds on Jalisco, Mexico offshore waters between 105W and 107W. Gentle to moderate northerlies are over the Baja offshore waters diminishing to light to gentle Tue night as the ridge weakens. These winds along with 3 to 5 ft seas will continue through early Friday morning when winds will increase to moderate again due to a strong ridge building northwest of the area. Gulf of California: Fresh to locally strong northwest flow is forecast across the southern half of the gulf waters tonight through Tuesday evening accompanied with seas to 7 ft. Gulf of Tehuantepec: Strong to near-gale north flow will surge through the gulf waters on early Wed morning, increasing to minimal gale force Wed night. Gale conditions are then expected to continue through Fri morning, with seas building to a maximum of around 12 ft. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... Gulf of Papagayo: Fresh to locally strong NE nocturnal winds are forecast starting Tue night and continuing through Wed evening with seas building to 7 ft downstream. A stronger drainage event is forecast to begin early Thu morning, and persist into the upcoming weekend with seas building to 10 ft. Gulf of Panama: Fresh to strong north nocturnal winds are forecast starting early Thu morning through Sat night with seas building to 8 ft. Light to gentle offshore flow will prevail elsewhere. REMAINDER OF THE AREA... Please see see Special Features Section above for details on upcoming gale force winds to impact the far NW portion of the area in the short-term. A very progressive pattern will continue to impact the the northwest portion of the area well into this week. The deep layer low pres system located to the northwest of the area and its related trough is preceded by mid to upper level moisture in the form of overcast cloudiness. Areas of rain along with scattered showers and isolated thunderstorms under upper level divergence that is present to the the east and southeast of this low have moved over the area north of about 28N and west of 119W. These clouds and precipitation will continue to advance eastward towards southern California and the northern and central Baja California through Wed per model moisture guidance fields. $$ Ramos