000 AXPZ20 KNHC 111957 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 2205 UTC Mon May 11 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 1800 UTC surface analysis and satellite imagery through 1945 UTC. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... A surface trough extends from low pressure over northern Colombia near 09N74W to 07N81W to 11N100W to 10N109W. The ITCZ continues from 10N109W to 07N120W to 10N127W then resumes from 09N134W to 06N140W. Numerous moderate and scattered strong convection is noted within 12N87W to 09N78W to 04N76W to 02N80W to 03N87W to 06N94W to 12N87W. Scattered moderate and isolated strong convection is within 12N109W to 04N103W to 04N110W to 12N109W, within 13N111W to 04N114W to 09N119W to 13N111W, and within 10N130W to 04N130W to 02N136W to 08N139W to 10N130W. OFFSHORE WATERS WITHIN 250 NM OF MEXICO... Haze and areas of smoke from agricultural fires in Mexico may reduce visibilities near the coast from the Tehuantepec region to near Cabo Corrientes to Baja California Sur per recent observations. Gulf of Tehuantepec: A locally tight pressure gradient over the Tehuantepec region that was supporting minimal gale force northerly winds has relaxed, with lingering fresh to strong winds as indicated by recent scatterometer data. Seas are still in the 8 to 12 ft range. The winds will diminish to 20 kt or less by early Tue, and residual seas will subside to less than 8 ft by Tue evening. Light onshore flow should prevail for the remainder of the week. A ridge axis extends from 1018 mb high pressure near 26N128W SE across the Revillagigedo Islands to near 13N100W. Gentle to moderate NW-N flow dominates the offshore waters along with seas of 5-7 ft, except 2-4 ft near the entrance to the Gulf of California and seas of 3 ft or less inside the Gulf of California under mainly light to moderate southerly flow. A dissipating cold front will approach the waters W of Baja California Tue night into early Wed. High pressure will build in behind the old boundary with NW-N winds increasing to moderate to fresh offshore of Baja California Wed night through Fri night, diminishing next weekend. These freshening winds will help to build seas to 7-10 ft offshore of Baja California during this same time period, subsiding by Sat night. Otherwise, little change is forecast for the rest of the week. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... Haze and areas of smoke from agricultural fires in Central America may reduce visibilities near the coast from Costa Rica to Guatemala. The Sangay Volcano located in Ecuador near 02S78W is producing a plume of volcanic ash that extends well SW over land reaching the vicinity of the eastern shore portion of the Gulf of Guayaquil. The Satellite Analysis Branch (SAB) in Washington, D.C. continues to issue Volcanic Ash Advisories, however the offshore waters are not currently forecast to be impacted. Light to moderate winds will continue to prevail across the offshore waters outside of plentiful convection, except moderate to fresh offshore winds in the Papagayo region during the next few late nights/early mornings. Seas will be mainly 4-7 ft in mixed long period SW and NW swell. A new set of long period SW swell will reach the waters offshore of Ecuador Thu night into early Fri with seas building to near 8 ft SW of the Galapagos Islands Fri and Fri night, subsiding on Sat and Sat night. REMAINDER OF THE AREA... A ridge axis extends from 1018 mb high pressure near 26N128W SE across the Revillagigedo Islands to near 14N100W, with another ridge extending SW of the high to 21N140W. A cold front extends from 30N130W to 26N140W. Mainly gentle to moderate trades prevail ahead of the front, except light to gentle anticyclonic flow near the ridging. Seas are 5-8 ft in mixed swell ahead of the front, mainly long period SW and NW swell, per recent altimeter data. Moderate to fresh NW winds are noted behind the front along with a set of NW swell building seas to 8-11 ft behind it. The front will weaken as it continues to traverse the northern waters while the set of NW swell gradually decays as it propagates E-SE, subsiding below 8 ft by Tue afternoon. Trades will increase slightly to moderate to fresh due to lower pressures along the ITCZ which will occasionally support seas around 8 ft through the week. The next front will approach 30N140W from the NW on Fri night, moving across the NW waters this weekend with another set of NW swell at 8-10 ft behind it. A set of long period SW swell may breach the equator Thu, building seas to 7-9 ft S of 10N and W of the Galapagos to 120W through Fri night, decaying Sat and Sat night. $$ Lewitsky