000 AXPZ20 KNHC 200944 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 1005 UTC Mon Jul 20 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 0930 UTC. ...SPECIAL FEATURES... Newly formed Tropical Depression Seven-E is centered near 18.0N 129.3W at 20/0900 UTC or more than 1045 nm west-southwest of the southern tip of the Baja California peninsula. It is moving northwest at 10 kt. An overnight ASCAT pass from 0529 UTC highlighted 20-30 kt winds within 180 nm of its center. Satellite imagery shows a band over the southern semicircle consisting of scattered moderate to isolated strong convection within 30 nm either side of line from 18N129W to 17N130W and to 18N131W. Scattered moderate convection is from 16N to 17N between 129W- 131W. The depression is forecast to move northwestward to west- northwestward at about the same forward speed for the next day or so due to a strong subtropical ridge located to its north. The depression is forecast to become a post-tropical cyclone near 19.3N 132.6W by late tonight. Please read the latest HIGH SEAS FORECAST- https://www.nhc.noaa.gov/text/MIAHSFAT2.shmtl and the latest Tropical Depression NHC Forecast/Advisory and Public Advisory at www.hurricanes.gov for more details. A tropical wave has its axis along 119W from 04N-18N with low pressure near 14N119W. This position is about 700 nm southwest of the southern tip of the Baja California peninsula. It is moving westward at 10-15 kt. Satellite imagery shows scattered moderate to strong convection within 120 nm of the low in the NW quadrant. Scattered moderate to isolated strong convection is seen from 13N to 14N between 119W-121W. The pressure gradient will continue to tighten around this system allowing for strong northeast to east winds from about 14N to 16N and between 121W and 123W. Winds with this low are expected to further increase through Mon along with building seas. Atmospheric conditions are expected to be conducive for development of this system, and a tropical depression could form during the next couple of days while it moves west-southwestward and then westward. This system has a medium chance of becoming a tropical cyclone during the next 48 hours. Please refer to the latest NHC Tropical Weather Outlook at www.hurricanes.gov for more details. ...TROPICAL WAVES... A tropical wave has its axis along 100W north of 34N to Acapulco, Mexico. It is moving westward at 10-15 kt. Isolated showers and thunderstorms are within 120 nm west of the wave from 10N to 13N. Similar activity is just inland the coast of Mexico between 98W and 100W. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough axis extends from a 1008 mb low over northwestern Colombia to 09N79W to 10N87W to 10N100W and continues westward to 09N111W where it is briefly interrupted by a trough that extends from 11N111W to 06N114W. It resumes at 09N114W to low pressure near 14N119W 1008 mb and to 15N123W. It then extends northwestward to 11N118W and to 15N123W. It resumes at 15N131W to 10N140W. Scattered moderate to strong convection is occurring within 180 nm south of the trough between 78W- 80W...between 89W-91W and within 120 nm north of the trough between 84W-87W and within 60 nm south of the trough between 85W- 87W. Scattered moderate convection is within 180 nm south of the trough between 112W- 115W. OFFSHORE WATERS WITHIN 250 NM OF MEXICO... A weak 1019 mb high is located near 30N129W. The associated relatively weak high pressure over the area is allowing for fresh northwest winds west of Baja California, to the north of Punta Eugenia, and mainly gentle northwest winds to the south of it. The high pressure will strengthen some tonight through Tue leading to the fresh winds increasing to strong speeds. These winds then diminish to moderate to fresh speeds late Tue and through the middle of the week. Gentle to moderate southerly winds will continue in the Gulf of California today, with seas in the range of 3-4 ft. The exception is that the southerly winds over the northern Gulf of California will increase to fresh to strong speeds on Tue and continue through Wed, with seas building slightly to 5 ft. The winds across the Gulf of Tehuantepec have diminished to moderate to strong speeds. With weak high pressure now in place north of the Tehuantepec region, these winds will then become light and gentle this afternoon and change little through the middle of the week. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, and WITHIN 750 NM OF ECUADOR... Fresh northeast to east gap winds will persist across the Gulf of Papagayo region through Mon, before diminishing to gentle speeds. Moderate to fresh southwest winds will remain over the waters south of 08N through the next few days. No significant long-period swell is expected in the Central American and equatorial offshore zones the next several days. REMAINDER OF THE AREA... A 1032 mb high pressure center is located well north of the area 42N142W, with a ridge extending from it to across the northern waters. The pressure gradient between the high and the monsoon trough is supporting mainly moderate northeast to east winds north of the ITCZ to 22N and west of about 118W, where seas are in the 5-7 ft range. Fresh northeast winds are present just to the northwest of the area, where seas are in the 6-8 ft range. Newly formed Tropical Seven-E centered near 18.0N 129.3W at 0900 UTC is forecast to become post- tropical late tonight near 19.3N132.6W. Winds and seas will gradually subside with system into Tue. The Special Features tropical wave along 119W from 03N to 18N with an embedded low pressure of 1008 mb near 14N119W is presently moving westward at 10-15 kt. This system is expected to be surrounded by atmospheric conditions favorable for development and a tropical depression could form from it within the next couple of days while it moves west-southwestward and then westward. See the Special Features section above for more details on both these systems. $$ Aguirre