000 AXPZ20 KNHC 152104 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 1957 UTC Thu Mar 15 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 2100 UTC. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... A surface trough axis extends from 09N84W to 04N104W. The intertropical convergence zone continues from 04N104W to 04N120W to 03N140W. Scattered moderate convection is from 02N to 05N between 86W and 92W. Scattered moderate convection is within 180 nm N of the ITCZ between 113W and 128W. ...DISCUSSION... OFFSHORE WATERS WITHIN 250 NM OF MEXICO... Please see the Special Features section for details on an ongoing Gulf of Tehuantepec gale event. A cold front extends from SW New Mexico near 31N108W to central Baja California Norte near 26N112W, dissipating to the NE Pacific near 22N120W. The front will move across the region through tonight and dissipate. Areas of light rain probably ongoing over the central portion of Baja California Sur ahead of the front. A post frontal trough will move through the region tonight. Looking ahead, another cold front will move across the region late Sat into Sun, possibly allowing another pulse of strong gap winds into the northern Gulf of California Fri night ahead of the front and again Sat night. Meanwhile long period NW swell of 8 to 9 ft is off the Baja California waters following the front. The swell will propagate to the waters of Baja California Sur tonight before decaying below 8 ft into Sat. Winds and seas will continue to diminish into early next week as high pressure builds over the region. Farther south, strong gap winds are possible off Cabo Corrientes by early Mon as the high pressure builds eastward into the region. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... Over Gulf of Papagayo, high pressure ridging over the Caribbean will bring fresh to strong NE to E winds mainly at night and in the early morning hours until early next week. The pressure gradient will re-strengthen in response to high pressure from the northern Caribbean. Over the Gulf of Panama, moderate to fresh winds will increase to fresh to strong to night with 4 to 6 ft seas building to 5 to 7 ft by late Fri. Elsewhere, expect gentle to moderate winds and 4 to 6 ft to persist. REMAINDER OF THE AREA... A dissipating cold front extends from central Gulf of California to the NE Pacific near 22N120W. The front will move east of the region and dissipate tonight. This will be followed by a post frontal trough from 30N117W to 27N120W to 25N130W that will shift east of the region and dissipate tonight. Another slightly stronger cold front will approach the NW corner tonight and move eastward over the waters north of 25N through Sun. Looking further ahead, a 1007 mb low and associated cold front will approach the NW corner Sun. Southerly flow may increase to fresh to strong north of 25N west of 130W ahead of this front Sun, shifting NW Mon as the front reaches from 32N130W to 20N140W by late Mon followed by 8 to 12 ft seas. Farther south into the deep tropics, a broad upper low is centered near 09N118W. Divergence aloft on the southeast side of the upper low along with modest trade wind convergence in the lower levels are supporting scattered convection within 180 nm norht of the ITCZ. Various altimeter satellite passes indicate 8 to 9 ft seas mainly due to NW swell, and this is expected decay below 8 ft through early Fri. The subtropical ridge north of the area will not get a chance to build substantially due to the frequency of passing cold fronts, keeping trade wind flow minimal through early next week. $$ Formosa