000 AXPZ20 KNHC 280225 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 033 UTC Tue May 28 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. This system is currently producing disorganized showers and thunderstorms over portions of Costa Rica, Nicaragua, and the adjacent Pacific waters. Abundant moisture and increasing instability are expected through Wed, which could lead to a very significant rainfall event over portions of Central America. Life-threatening flash flooding and mudslides will be possible in areas of mountainous terrain. Please refer to your local meteorological service for more details. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough extends across northern Costa Rica to 1008 mb low pressure located near 09N89W to 1010 mb low pressure located near 12N100W to 08N110W to 09N125W to 06N132W. The ITCZ continues from 06N132W to beyond 06N140W. Scattered moderate to isolated strong convection is noted from 05N to 09N between 82W and 90W, from 07N to 14N between 97W and 105W, and from 06N to 11N between 120W and 135W. ...DISCUSSION... OFFSHORE WATERS WITHIN 250 NM OF MEXICO... Gulf of California: Winds across central and southern portions will increase to 10-15 kt through Tue with seas building 2-3 ft as a ridge builds W of Baja California. Afterwards, mainly light and variable winds will dominate the Gulf during the next several days. Elsewhere, building high pressure across the offshore forecast waters W of Baja California and north of 20N will produce fresh to locally strong NW to N winds off Baja California through Tue night, with seas to 8 ft. The ridge will weaken thereafter, allowing winds to diminish. Seas will subside accordingly as well, except for off the northern coast of Baja California Norte where another round of NW swell will propagate across the region late Tue through 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 at least mid week. Latest scatterometer data 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. Low pressure of 1008 mb embedded within the broad gyre will meander offshore the coast of Nicaragua the next couple of days. The monsoon trough will lift northward by midweek, with the low pressure likely moving inland over Central America. The southerly monsoon flow is forecast to strengthen to 20-25 kt Tue through Wed. Seas will build to 8-12 ft by mid week in this enhanced monsoon flow combined with cross equatorial SW swell. REMAINDER OF THE AREA... A ridge extends from 1027 mb high pressure centered northwest of the area near 36N135W 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 will cover the waters south of 13N between 85W and 115W by late Tue. $$ GR