016 AXPZ20 KNHC 290253 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 0405 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 0000 UTC surface analysis and satellite imagery through 0215 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 overnight hours. These winds will build seas to 7-9 ft locally in the northern Gulf of California. Winds will diminish to fresh to strong early Mon 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 1004 mb low pressure is noted near 18N109.5W. Numerous moderate and isolated strong convection is noted within 120 nm in the NE quadrant of the low with scattered moderate convection noted elsewhere within 210 nm in the N semicircle and 90 nm in the S semicircle of the low. Although the system does not currently have a well-defined center, additional development is possible, and a tropical depression could form tonight or Monday as the system moves northwestward at about 15 mph. After that time, additional development will become unlikely as the disturbance moves over cooler waters. 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 Colombia/Ecuador border with axis near 79W/80W, moving westward at around 10 kt. Scattered moderate convection is noted from the equator to 03N along the coast. A tropical wave is cross the Tehuantepec Region with axis near 94W/95W, moving westward at 10-15 kt. Scattered moderate and isolated strong convection is noted N of 14N between 92W and 96W. A tropical wave extends from 02N to 20N with axis near 132W/133W, moving westward at around 10-15 kt. There is no significant convection noted with this wave. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough axis extends from northern Colombia near 11N74W to 07N94W to 15N103W to low pressure near 18N109.5W to low pressure near 18N116W to 12N120W to 10N130W to 08N140W. Scattered moderate and isolated strong convection is noted from 04N to 10N between 80W and 93W, within 14N112W to 13N106W to 06N99W to 05N101W to 05N106W to 10N111W to 14N112W, within 12N121W to 13N113W to 09N118W to 09N121W to 12N121W, and from 07N to 12N between 123W and 126W. Scattered moderate convection is noted from 08N to 12N between 98W and 101W, from 08N to 11N between 129W and 131W, from 08N to 09N between 134W and 136W, and from 06N to 08N between 138W and 140W. 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, 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 and Fri 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 30N140W E-SE toward 17N121W. 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. Mainly moderate to locally fresh N-NE flow prevails between 140W and a pair of low pressures located near 18N116W 1006 mb and near 18N109.5W. 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. 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