000 AXPZ20 KNHC 032146 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 2205 UTC Fri Mar 3 2017 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 2115 UTC. ...SPECIAL FEATURE... Strong high pressure over the southern United States and Gulf of Mexico is inducing a gap gale wind event consisting of north to northeast 30-40 kt winds. The latest satellite imagery depicts a large swath of possible spreading downstream away from the gulf reaching to near 11N between 95W and 99W. In addition, the imagery shows cloud streamers emanating a large distance, roughly about 400 nm, from both the east and west edges of the gulf. This is indicative of the presence of a gale wind gap event. The gale winds are forecast by model guidance to continue through tonight, then diminish to minimal gale Saturday through Sunday morning. The high will shift east of the Gulf basin by later Sunday which will allow the gap winds to decrease below gale force. See latest NWS High Seas Forecast under AWIPS/WMO headers MIAHSFEP2/FZPN03 KNHC for more details. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The ITCZ axis extends from 04N88W to 03N100W to 03N110W to 03N120w. No significant convection is noted. ...DISCUSSION... OFFSHORE WATERS WITHIN 250 NM OF MEXICO... Strong high pressure over the Gulf of Mexico is forcing a Tehuantepec gale. Please refer to the special features section above for more details. The combination of strong high pressure over the inter-mountain region of the U.S. and troughing extending from northwest to southeast just east of the Gulf of California is generating strong northwest winds over the far northern waters of the Gulf of California. Winds and seas will quickly diminish and subside through the remainder of this afternoon as the high to the northeast weakens and shifts eastward. Elsewhere, light to gentle winds and 4 to 6 ft seas will prevail across the offshore waters of Mexico through Sunday. High pressure building behind a cold front expected to move across the northeast and north-central waters Monday will bring fresh to locally strong north to northwest winds along with seas as high as 9 ft to the waters along the Baja coast Monday through Tuesday night as large set of northerly swell propagates into those areas. The pressure gradient between the high and thermal trough trough that sets up along the coast of Mexico will also support strong northwest winds over much of the Gulf of California starting late Monday night and expected to last through Wednesday with seas possibly building to 8 ft in the central and southern portions of the gulf. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... High pressure north and east of the region will continue to force fresh to strong northeast winds through the Gulf of Papagayo, spanning from about 08N to 13N to include the Gulf of Fonseca, and as far west as 93W the next several days, with the strongest winds occurring late night through the morning hours. Seas will build to 8 to 10 within this area, with the swell propagating westward while merging with large swell from the Gulf of Tehuantepec winds. Over the Gulf of Panama...winds will freshen each night before diminishing during the late afternoon hours through Monday. A period of fresh to strong winds and seas to 8 ft will occur Saturday through Sunday night. Elsewhere...light to gentle breezes and seas of 4 to 6 ft will persist through early next week. REMAINDER OF THE AREA... The pressure gradient between 1030 mb high pressure centered to the north of the discussion area near 35N136W and lower pressure in the vicinity of the ITCZ is still maintaining fresh to strong northeast to east winds from about 12N to 17N and west of 134W with seas of 8 to 9 ft covering a broader area from about 05N to 25N west of 121W. The winds and seas will diminish and subside through Saturday night as the aforementioned high pressure is shunted to the southwest and weakens in response to an approaching cold front from the N. By Sunday night, north swell following in the wake of the cold front is forecast by Wave model guidance to build seas to the range of 8-10 ft over the far northern waters north of 28N west of 125W. Wave model guidance shows this swell propagating to the southeast, and spreading across the majority of the northern and central waters by Tuesday. $$ Aguirre