175 AXPZ20 KNHC 292115 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 2115 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 1800 UTC surface analysis and satellite imagery through 2100 UTC. ...SPECIAL FEATURES... ...Heavy Rainfall Potential Over Central America and Southern Mexico... A large, low-level cyclonic circulation that is typical for this time of the year, called a Central American Gyre, will persist across the far eastern tropical Pacific and Central America for the next several days. 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. Please refer to your local meteorological service for more details. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough extends from 12N87W to 1011 mb low pressure near 12.5N88W to 1007 mb low pressure near 14N97W to 09N110W to 07N127W. The ITCZ continues from 07N127W to beyond 06N140W. Scattered moderate and isolated strong convection is noted within 120 nm north of the monsoon trough between 100W and 105W. Elsewhere, scattered moderate convection is occurring within 180 nm south of the monsoon trough between 90W and 99W and from 05N to 07N between 85W and 88W. ...DISCUSSION... OFFSHORE WATERS WITHIN 250 NM OF MEXICO... Strong winds and building seas persist on the southern periphery of 1007 mb low pressure centered near 14N97W. Altimeter data from 15Z revealed 10-13 ft seas south of the low, and seas will remain 8-12 ft as the low tracks northeast over the next couple days and moves inland over the isthmus of Tehuantepec. Some slow tropical development of this system is possible during the next couple of days. Farther north, recent altimeter data showed fresh NW winds off Cabo San Lucas between 1008 mb low pressure near 22.5N108W and a high pressure ridge west of the region. This weak low is expected to weaken through tonight as associated winds and seas diminish. Gulf of California: Light to gentle breezes will prevail over the Gulf through Thu night. Moderate to fresh S to SW winds will develop in the northern Gulf Fri and persist through Sat night as a low pressure trough supports a tightening pressure gradient over the region. 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. Available altimeter data from earlier today indicated gentle to moderate SW to W breezes were occurring south of the monsoon trough off the coast of Nicaragua. Seas to 8 ft in SW swell likely extend as far east as 86W based on model guidance and an earlier altimeter pass in the region. The SW monsoon flow is forecast to strengthen to 20-25 kt off Guatemala tonight into Thu with seas building to near 13 ft as locally generated wind waves in the enhanced monsoon flow combine with cross-equatorial SW swell. Fresh SW monsoon flow will likely persist off Guatemala into the weekend with seas remaining 8 ft or greater. Looking ahead, a set of SW swell will move into the Galapagos offshore waters Fri night and maintain seas to 8 ft through the weekend and into early next week. REMAINDER OF THE AREA... A ridge extends southeastward from 1027 mb high pressure near 33N138W to the Revillagigedo Islands. An 18Z scatterometer pass confirmed fresh NE trade winds continue between the ridge and the ITCZ generally west of 130W. Associated seas in this region remain 7-8 ft based on earlier altimeter data. Moderate to fresh winds will prevail over this area for the next several days with little change expected in the overall weather pattern. Long period, cross-equatorial SW swell continues to dominate much of the forecast waters roughly south of 20N and east of 130W. Seas 8 ft or greater cover much of the waters from 05N to 13N between 85W and 108W this afternoon. Seas will gradually subside over the next couple of days as low pressure tracks toward southern Mexico and wind speeds diminish over the area. Another set of SW swell will move into the far southern waters Thu and maintain 8 ft seas south of the Equator through the weekend. $$ Reinhart