000 AXPZ20 KNHC 090902 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 1005 UTC Thu Jan 9 2020 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 0745 UTC. ...SPECIAL FEATURES... Gulf of Tehuantepec Gale Warning: Scatterometer data from the past several hours confirmed 35-40 kt winds over the Gulf of Tehuantepec, along with a recent ship report. Wave heights were analyzed to 17 ft early this morning near the Gulf, with seas 12 ft or greater extending well downstream beyond 100W. High pressure across the SW Gulf of Mexico will maintain a strong pressure gradient over southern Mexico through this morning which will allow gale conditions to persist. Winds are expected to diminish below gale force by this afternoon as the pressure gradient weakens. Looking ahead, the next gale force wind event is forecast to begin Sat evening and continue through Sun as a strong cold front will move across the Gulf of Mexico. Gulf of Papagayo Gale Warning: A strong N to S pressure gradient persists across Central America early this morning with minimal gale force NE winds likely occurring over and downstream of the Gulf of Papagayo. Gale force winds will persist through the afternoon, diminishing to strong to near gale force by this evening. Those conditions will then persist through the upcoming weekend and into early next week. Also, seas are building to 12-14 ft early this morning in response to the gale force winds. 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 on both gale warnings. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... A trough extends from 1007 mb low pressure over northern Colombia near 08N75W to 03N84W to 04N89W. The ITCZ continues from 04N89W to 06N110W to 07N124W, then resumes from 08N129W to 06N135W to 07N140W. Scattered moderate and isolated strong convection is noted within 120 nm N of the ITCZ between 111W and 124W, and also from 07N to 10N between 133W and 140W. Additional scattered moderate and isolated strong convection is noted from 13N to 22N between 127W and 140W under an area of upper level diffluence. OFFSHORE WATERS WITHIN 250 NM OF MEXICO... See the Special Features section above for more details on the Gale Warning for the Gulf of Tehuantepec. The pressure gradient off Baja California will tighten later today through Fri night between an offshore high pressure ridge and weak low pressure that will track SE near the coast of California, then devolve into a surface trough. This will produce fresh to strong NW winds offshore of Baja California Norte and in the northern Gulf of California during this time period. Strong winds will spread southward across the central and southern Gulf late this upcoming night through early Sat. NW swell moving into the waters north of Punta Eugenia will build seas to 12 ft north of 29N today into tonight, with seas subsiding below 8 ft by Fri night. Another set of long-period NW swell will move through the Baja California waters Sun through early next week. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... See the Special Features section above for more details on the Gale Warning for the Gulf of Papagayo. Earlier altimeter data indicated 8-10 ft seas, likely in mixed NW swell and NE wind waves, extending well downstream of the Papagayo region to near 09N91W. Moderate northerly swell generated by gales in the Gulf of Tehuantepec will continue to impact the waters off Guatemala and El Salvador through today. Fresh to occasionally strong N to NE winds will pulse in the Gulf of Panama through early Fri. Elsewhere, expect winds less than 20 kt and seas less than 8 ft for the next several days. REMAINDER OF THE AREA... A 1035 mb high pressure center NW of the area near 36N147W maintains a surface ridge extending southeastward across the northern forecast waters toward the Revillagigedo Islands. Meanwhile, a surface trough is analyzed from 14N126W to 04N127W, with a 1010 mb low pressure center near 09N127W. Scattered moderate and isolated strong convection is noted from 06N to 12N between 125W and 132W. The enhanced pressure gradient between these features is supporting a large area of fresh to strong trades across the waters roughly N of 07N and west of 125W. As the low pressure center moves westward through Fri, expect near gale force winds NW-N of the low with seas building to 12-14 ft. An expansive area of fresh to strong trades with seas 8 ft or greater will persist W of 120W through the weekend, diminishing some by early next week. A set of long-period NW swell moving SE across the waters E of 125W will continue through the upcoming night. Looking ahead, a larger set of northerly swell will move into the northern waters on Sun and spread southward through early next week. $$ Lewitsky