000 AXPZ20 KNHC 120744 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 1005 UTC Tue May 12 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 0830 UTC. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... A surface trough extends from a 1010 mb low pressure located over northern Colombia near 09N74W to 08N90W to 10N100W to 08N112W. The ITCZ continues from 08N112W to 09N130W to 07N140W. A trough is within the ITCZ along 132W from 05N to 13N. Scattered moderate to isolated strong convection is from 03N to 09N between 80W and 94W, from 09N to 13N between 104W and 110W, from 07N to 11N between 130W and 135W, and from 06N to 09N W of 135W. 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, and across the area between Las Marias and Revillagigedo Islands. Gulf of Tehuantepec: A ridge across the eastern slopes of the Sierra Madre Mountains and the western Gulf of Mexico will continue to support fresh to strong northerly winds across the Tehunatepec region through this morning, with seas of 8 to 11 ft. A recent scatterometer pass confirmed the presence of fresh to strong northerly winds across the area, particularly N of 14N between 94W and 95.5W. The winds will diminish to 20 kt or less by early this afternoon, and residual seas of 8 to 9 ft will subside to less than 8 ft by this evening. Light onshore flow should prevail for the remainder of the week. A ridge dominates the offshore forecast waters of Baja California producing gentle to moderate NW-N winds. Sea heights are in the 5-7 ft range, except 3-5 ft near the entrance to the Gulf of California. This weather pattern will persist over the next few days. A building ridge across the northern forecast waters will bring an increase in winds to 20-25 kt, mainly N of Cabo San Lazaro Wed night through Fri night. Seas of 8-9 ft in NW swell will reach the waters N of Punta Eugenia by late Thu, and propagate SE between Punta Eugenia and Cabo San Lazaro through Fri night, subsiding to less than 8 ft by late Sat. Mainly light to moderate southerly flow and seas of 3 ft or less will prevail inside the Gulf of California, with the expection of the northern part of the Gulf where a dissipating cold front moving across the area could briefly bring fresh winds. 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 currently extends SW over land. The Satellite Analysis Branch (SAB) in Washington, D.C. continues to issue Volcanic Ash Advisories. The latest advisory indicates that the plume of volcanic ash will remain over land while diminishing later today. Light to moderate winds will continue to prevail across the offshore forecast waters, except in the Gulf of Papagayo where moderate to fresh offshore winds are expected during the overnight and early morning hours through Wed. Seas will be mainly 4-7 ft primarily in long period SW swell. A new set of long period SW swell, with a leading edge period of 19 to 21 seconds will reach the waters between Ecuador and the Galapagos Islands by Thu night into early Fri, and the Pacific coast of Central America by late Fri. Seas will build to 8 ft SW of the Galapagos Islands Fri and Fri night, subsiding on Sat and Sat night. REMAINDER OF THE AREA... A ridge dominates much of the northern forecast waters while a cold front extends from 30N127W to 25N140W. A recent altimeter pass provided observations of seas in the 8 to 10 ft range in the wake of the front, forecast to dissipate today as it moves eastward across the northern forecast waters. Moderate to fresh NW winds are noted behind the front along with a set of NW swell. This swell event will gradually decay as it propagates E-SE, subsiding below 8 ft by early this afternoon. As high pressure builds across the area, behind the above mentioned cold front, expect a slight increase in the trade wind flow with seas building to around 8 ft W of 130W 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 cross equatorial long period SW swell will propagate across the south waters between Ecuador and 120W on Wed, building seas to 9-10 ft S of the equator, and to 8-9 ft S of 10N and W of the Galapagos to about 120W through Fri night, decaying Sat and Sat night. $$ GR