000 AXPZ20 KNHC 290829 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 1005 UTC Mon Jun 29 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 0815 UTC. ...SPECIAL FEATURES... Gulf of California Gale Warning: Troughing extends from the desert SW United States through the far NW Gulf of California to Baja California Norte. SW winds ahead of the troughing are being enhanced by gap wind flow with strong to minimal gale force winds forecast through the next few hours. These winds are building seas to 7-9 ft locally in the northern Gulf of California. Winds will diminish to fresh to strong by sunrise and persist through early Tue. Please read the latest NHC High Seas Forecast at: https://www.nhc.noaa.gov/text/MIAHSFEP2.shtml for further details. Low pressure S-SW of Mexico: Broad 1006 mb low pressure is noted near 19N111W. Scattered moderate to strong convection is noted within 120 nm of the low center in the SE semicircle. The disturbance is moving northwestward toward colder water, but it could still briefly become a tropical depression if showers and thunderstorms redevelop today. Increasing winds and seas and thunderstorms can be expected over the offshore waters in the vicinity of the low. This low has a medium chance of tropical cyclone development during the next 48 hours. Please read the latest NHC Tropical Weather Outlook at https://www.nhc.noaa.gov/text/MIATWOEP.shtml for more details. ...TROPICAL WAVES... A tropical wave is crossing Panama and extends southward to near the coast of NW Ecuador border with axis near 80W/81W, moving westward at around 10 kt. Scattered moderate and isolated strong convection is noted from 03N to 05N between 77W and 79W, and from 06N to 09N between 81W and 84W. A tropical wave is crossing the Tehuantepec Region with axis near 95W/96W, moving westward at around 10 kt. Scattered moderate and isolated strong convection is noted N of 14N between 93W and 97W and from 05N to 07N between 93W and 95W. A tropical wave extends from 02N to 19N with axis near 133W/134W, moving westward at around 10 kt. There is no significant convection noted with this wave. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough axis extends from northern Colombia near 11N75W to 10N95W to 08N98W to 16N103W to low pressure near 19N111W to low pressure near 18N116W to 12N120W to 10N130W to 08N140W. Scattered moderate and isolated strong convection is noted from 03N to 08N between 85W and 93W, from 09N to 14N between 106W and 112W, from 09N to 12N between 124W and 127W, from 08N to 11N between 130W and 133W, from 05N to 09N between 134W and 134W. OFFSHORE WATERS WITHIN 250 NM OF MEXICO... Please read the Special Features section for more details about the gale warning in the Gulf of California and regarding broad low pressure S-SW of Mexico. Elsewhere, recent scatterometer passes show mainly gentle to moderate onshore winds prevail along with 4-7 ft seas primarily in southerly swell. Little change is expected through the week, except in the Tehuantepec Region where a gap wind event is expected Fri afternoon and night. Northerly winds will increase to fresh to locally strong there resulting in building seas of 7-9 ft for the end of the week. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... Fresh to locally strong winds will pulse over and downstream of the Papagayo region through Wed. These winds may assist in the development of broad low pressure by mid-week which will shift W-NW of the area toward the end of the week. Seas will build to 7-9 ft with the pulsing winds and low pressure area. Moderate to occasionally fresh monsoon flow will prevail over the waters S of 10N through early week. Long period southerly swell reach this same area helping to build seas to 5-8 ft. REMAINDER OF THE AREA... A ridge axis extends from 30N135W E-SE toward 26N117W. A set of northerly swell with seas of 7-9 ft has breached S of 30N per recent altimeter and ship observations, reaching to 27N between 130W and 140W. Scatterometer data shows that mainly moderate to locally fresh N-NE flow prevails between 140W and a pair of low pressures located near 18N116W 1007 mb and near 19N111W 1006 mb. Seas in this region are mainly in the 5-7 ft range. Moderate to fresh monsoonal flow persists south of the monsoon trough between 100W and 120W helping to support 7-10 ft seas as indicated by recent altimeter data. Long period southerly swell of 7-8 ft extends elsewhere S of 10N between 90W and 125W to the equator. The northerly swell will spread E-SE to between 120W and 135W through the early part of the week, decaying thereafter. Monsoonal flow and the area of 7-10 ft seas will diminish and decay by early Tue. A new set of southerly swell will breach the equator by late Tue, building seas to 7-9 ft between 100W and 135W all the way to 08N through mid-week, decaying W of 120W thereafter. E of 120W, monsoonal flow will increase back to fresh and with the underlying southerly swell an area of 7-10 ft seas will persist S of 10N between 95W and 120W for the end of the week as weak low pressure may form along the monsoon trough in the area. $$ Lewitsky