000 AXPZ20 KNHC 050844 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 1005 UTC Tue Mar 5 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 0830 UTC. ...SPECIAL FEATURES... Open East Pacific Waters Gale Warning: A pre-frontal trough is identified extending from 30N131W to 20N139W, and a cold front extends from 30N133W to 23N140W in association with a 1002 mb low centered at 33N137W. Scattered moderate convection exists north of 27N between the trough and the front. Recent scatterometer data showed gale force westerly winds to the N of 28N and west of the front. An earlier altimeter pass measured 10 to 14 ft seas in this same area, likely now slightly higher at around 16 ft. The cold front will steadily progress eastward across our northern waters. Winds will gradually diminish and the gale warning should be lifted by 1800 UTC. Associated maximum NW swell of about 15 ft in our area will propagate southeastward while gradually diminishing. Peak seas should diminish below 12 ft by Tue night and below 8 ft by Thu morning. Gulf of Tehuantepec Gale Warning: High pressure building in E of the Sierra Madre Oriental in Mexico behind a strong cold front is inducing a gap wind event in the Gulf of Tehuantepec. Strong winds funneling through the Chivela Pass will reach gale force by sunrise this morning and continuing as a gale through early Thu morning. This Tehuantepecer should end Fri afternoon. It is anticipated that winds will peak at 40-45 kt and seas reach almost 20 feet early Wed morning. Please read the latest High Seas Forecast issued by the National Hurricane Center under AWIPS/WMO headers FZPN03 KNHC/HSFEP2 or at website https://www.nhc.noaa.gov/text/MIAHSFEP2.shtml for further details about these gale warnings. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... A trough axis extends from near the Costa Rica/Panama border near 09N83W to 06N90W. The Intertropical Convergence Zone axis continues from 06N90W to 03N110W to 02N120W to 06N140W. Scattered moderate convection is from 01N to 03N between 116W and 119W. As is normal for this time of the year, a second convectively active ITCZ is analyzed S of the Equator. ...DISCUSSION... OFFSHORE WATERS WITHIN 250 NM OF MEXICO... Gulf of Tehuantepec: A Gale Warning is in effect for the Gulf of Tehuantepec. Please read the Special Features section for details. On Thu, a weakening cold front will reach Baja California Norte with minimal impacts. Conditions should remain benign W of Baja California for the next several days. No large long-period swell is anticipated to affect the region. Gulf of California: Developing low pressure over the U.S. Great Basin will support nocturnal pulsing of fresh to strong SW to W in the northern Gulf of California Thu night and Fri night. Generally tranquil marine conditions are expected elsewhere across the Gulf through at least Sat night. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... Gulfs of Fonseca, Papagayo, and Panama: A moderate pressure gradient in the western Caribbean combined with nocturnal drainage flow will produce enhanced winds in the Gulfs of Papagayo and Panama each evening through at least Sat night. The forcing is strongest later today through Thu nights and also causes strong breeze conditions in the Gulf of Fonseca those three evenings. Winds should peak around near gale in the Gulf of Papagayo Wed and Thu morning with peak seas of 10-12 ft. Winds should peak around strong breeze in the Gulf of Panama Wed, Thu, and Fri mornings with peak seas of around 8 ft. No large long- period swell are expected to impact the area for the next several days. A surface trough is analyzed Just W of the Galapagos Islands offshore waters with scattered moderate convection along the western zone boundary. This activity should diminish later today as the trough drifts westward. Otherwise, NE swell generated by a strengthening gap wind event in the Gulf of Panama will propagate SW toward the Galapagos Islands later in the week with seas building to 5-7 ft. REMAINDER OF THE AREA... Marine conditions have deteriorated N of 25N W of 135W as a low pressure system and associated frontal boundaries affect this region. Please see the Special Features Section for more details on a Gale Warning. Elsewhere, long-period NW swell mixing with tradewind flow is maintaining an area of 8 to 9 ft seas from 05N to 12N between 129W and 135W. These seas will gradually subside to less than 8 ft in the next several hours. $$ Lewitsky