000 AXPZ20 KNHC 290218 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 106 UTC Wed May 29 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 0000 UTC surface analysis and satellite imagery through 0300 UTC. ...SPECIAL FEATURES... ...Heavy Rainfall Potential Over Central America... A large low level cyclonic circulation that is typical for this time of the year, called a Central American Gyre, is forecast to persist across the far eastern tropical Pacific and Central America for the next several days. A low pressure of 1009 mb embedded within the broad gyre is centered offshore the coast of Nicaragua. This system is expected to move inland over Central America on Wednesday. Locally heavy rainfall is likely to continue over portions of Central America and southern Mexico during the next several days. These rains could cause flash flooding and mudslides in areas of mountainous terrain. Currently, satellite imagery shows clusters of moderate to strong convection over parts of Nicaragua. Please refer to your local Meteorological Weather Service for more details. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough extends across northern Costa Rica to 1009 mb low pressure situated near 11N88W to another 1009 mb low pressure located near 12N98W to 08N113W to 10N127W. The ITCZ continues from 10N127W to beyond 07N140W. Scattered moderate to isolated strong convection is observed from 10N to 12N between 85W and 89W, and from 08N to 13N between 95W and 105W. Scattered moderate convection is noted from 06N to 09N between 105W and 119W. Similar convection is also seen N of 06N between 81W and 85W to the coast of western Panama and Costa Rica. ...DISCUSSION... OFFSHORE WATERS WITHIN 250 NM OF MEXICO... A ridge extends across the northern forecast waters reaching the Baja California peninsula. The most recent scatterometer data provided observations of fresh to strong NW over the waters N of 22N E of 117W to the coast of Baja California. Mainly moderate NW winds dominates the remainder of the offshore waters. Seas are in the 6 to 8 ft seas in this region. Light to gentle winds, with seas in the 4-6 ft range prevail elsewhere over the open waters off Mexico. Light winds and seas 2 ft or less are noted over the Gulf of California. High pressure will slightly weaken on Wed allowing winds to diminish winds to 20 kt or less west of the Baja California peninsula, with seas subsiding below 8 ft. A large area of disorganized showers and thunderstorms is located a few hundred miles south of the Tehuantepec region, and is associated with a trough of low pressure. Some gradual development of this system is possible during the next several days as it moves slowly northeastward. As a result, SW winds will strengthen south of the Gulf of Tehunatepec beginning this Wed. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... Please see the Special Features section for more information about the Central American Gyre, which will continue to bring locally heavy rains to parts of Central America and the adjacent offshore waters through the next several days. Later in the week, the Central American Gyre is expected to strengthen as the monsoon trough moves north. Latest surface observations indicate moderate to fresh S to SW winds S of the monsoon trough, with seas in the 6-8 ft range. Moderate to locally fresh winds, and seas of 5-6 ft prevail N of the monsoon trough. The southerly monsoon flow is forecast to strengthen to 20-25 kt by Wed. Seas will also build to 8-12 ft by mid week as locally generated wind waves in the enhanced monsoon flow combines with cross equatorial SW swell. REMAINDER OF THE AREA... A ridge extends from 1028 mb high pressure centered near 33N137W southeastward through the Revillagigedo Islands. The pressure gradient between the ridge and lower pressure in the vicinity of the ITCZ is supporting moderate to fresh NE winds across much of the area north of the ITCZ and west of 120W. Moderate to fresh winds will continue to prevail over this area the next several days. Long period cross equatorial SW swell will continue to dominate much of the forecast waters. Seas 8 ft or greater cover the waters south of 12N between 85W and 115W. Seas will slowly subside over the next couple of days, with areal coverage of seas 8 ft or greater gradually decreasing. $$ GR