484 AXPZ20 KNHC 291530 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 1530 UTC Sun Jul 29 2018 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 1200 UTC surface analysis and satellite imagery through 1500 UTC. ...SPECIAL FEATURES... Tropical Depression Gilma centered near 15.9N 138.5W at 29/1500 UTC or 970 nm E of Hilo Hawaii moving W at 12 kt. Estimated minimum central pressure is 1008 mb. Maximum sustained wind speed is 30 kt with gusts to 40 kt. Scattered moderate and isolated strong convection is within 300 nm in the E quadrant of Gilma. See latest NHC forecast/advisory under AWIPS/WMO headers MIATCPEP3/WTPZ33 KNHC for more details. ...TROPICAL WAVES... A tropical wave extends north of 09N along 91W moving west at around 10 kt. Scattered moderate and isolated strong convection is observed just offshore of the coast of Central America and Mexico where the tropical wave is interacting with the monsoon trough. This convection is occurring within 210 nm east of the wave axis, and also within 480 nm west of the wave axis. A tropical wave extends from 04N to 16N along 128W moving W at 10 to 15 kt. Scattered moderate convection is observed from 12N to 15N between 122W and 125W. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough extends from low pressure near 09N75W to 10N88W, then resumes from 11N96W to 08N113W. Segments of the intertropical convergence zone axis extend from 08N113W to 10N121W to 08N126W, then resumes from 07N129W to 13N137W. Scattered moderate to strong convection is from 02N to 07N within 240 nm west of the Pacific coast of Colombia. Scattered moderate and isolated strong convection is from 07N to 10N between 82W and 88W, and also from 15N to 18N between 100W and 102W. Scattered moderate convection is within 75 nm either side of the axis between 132W and 137W. ...DISCUSSION... OFFSHORE WATERS WITHIN 250 NM OF MEXICO... Gulf of Tehuantepec: Moderate to fresh gap winds will diminish later this morning over the Gulf of Tehuantepec. Weaker gap winds are expected thereafter through early next week due to diminishing high pressure north of the area. Looking ahead, stronger gap winds are likely by the middle of the week as higher pressure builds north of the area and lower pressure develops to the south. Elsewhere a trough persists from Baja California Norte southeast to 22N129W. This is resulting in a fairly weak pressure pattern across the open offshore waters of Mexico. Scatterometer data show light to gentle NW winds in most areas and 3 to 5 ft seas. An earlier scatterometer pass indicated gentle to moderate SE flow persisting along the length of the Gulf of California. Little change is expected through the middle of the week. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... Gulf of Papagayo: Moderate easterly flow is expected through the middle of the week, occasionally pulsing to fresh. Gentle to occasionally moderate E winds are forecast elsewhere N of the monsoon trough which is meandering between 08N and 10N. Moderate to locally fresh southerly winds are forecast S of the monsoon trough into early next week accompanied by 5 to 7 ft seas. REMAINDER OF THE AREA... See the special features section for information on Tropical Depression Gilma and the tropical waves section. Convection is pulsing near broad low pressure centered west of the offshore waters of Central America near 10N105.5W. Scattered moderate to strong convection is within 210 nm in the north semicircle of the low. The estimated sea level pressure is 1090 mb. While there has been steady development of this system over the past 12 to 24 hours, there remains some uncertainty about its development over the next couple of days. There is a moderate chance for tropical cyclone development through the next five days. Expect fresh to occasionally strong winds in this convection, with seas building to 8 ft through the next two to three days. Otherwise, ridging will persist north of 20N west of 120W through the middle of the week, supporting moderate N to NE winds and 5 to 7 ft seas in that area. Moderate to locally fresh southerly forecast elsewhere S of the monsoon trough or roughly 10N for the next several days. $$ Lewitsky