000 AXPZ20 KNHC 200355 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 0405 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 0000 UTC surface analysis and satellite imagery through 0345 UTC. ...SPECIAL FEATURES... Low pressure of 1007 mb is centered near 17N128W, or about 1045 nm west-southwest of the southern tip of the Baja California peninsula. It is moving west-northwestward at about 13 kt. Afternoon scatterometer data depicted fresh to strong winds with the low. Satellite imagery shows that convection has increased over the past few hours. The convection consists of the scattered moderate to strong type within 90 nm of the low in the NW quadrant and within 60 nm of the low in the SW quadrant. Scattered moderate convection is elsewhere within 120 nm of the low in the SW and W quadrants. This system could become a short-lived tropical depression later tonight or on Mon while it continues to move in a west- northwestward track. It has a medium chance of becoming a tropical cyclone during the next 48 hours. A tropical wave has its axis along 118W from 04N-18N, moving westward at 10-15 kt. Satellite imagery shows scattered moderate to strong convection within 120 nm west of the wave from 14N to 15N. Scattered moderate to isolated strong convection is seen from 15N to 17N within 180 nm east of the wave. Low pressure is likely to form along the wave later today leading to a tightening of the gradient. This should produce 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 around the middle of the week 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 on these Special Features. ...TROPICAL WAVES... A tropical wave has its axis along 98W north of 04N to inland Mexico west of Puerto Angel near 16N98W. It is moving westward at 10-15 kt. Isolated showers and thunderstorms are within 120 nm west of the wave from 10N to 14N. Similar activity is just inland the coast of Mexico between 96W and 98W. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough axis extends from a 1007 mb low over northwestern Colombia to 09N79W to 08N83W to 10N89W and continues westward to low pressure near 09N103W 1010 mb and to low pressure near 09N112W. It then extends northwestward to 11N118W and to 15N123W. It resumes at 14N131W to 10N140W. Scattered moderate to strong convection is occurring within 120 nm north and 60 nm south of the trough between 81W-84W. Scattered moderate to isolated strong convection is within 120 nm north of the trough between 104W-106W, also within 120 nm south of the trough between 105W-108W and between 111W-118W. Scattered moderate convection is within 120 nm south of the trough between 78W-81W and also between 87W-90W and from 04N to 07N between 81W-86W. OFFSHORE WATERS WITHIN 250 NM OF MEXICO... 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 to around 6 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 1033 mb high pressure center is located well north of the area 44N140W, 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. The Special Features 1007 mb low near 17N28W is forecast to continue west-northwestward through Mon, with potential for it to become a short-lived tropical depression later tonight or on Mon. The Special Features tropical wave along 118W from 03N to 18N is presently moving westward at 10-15 kt. Low pressure is likely to form along this wave later today. This system is expected to be surrounded by atmospheric conditions favorable for development of this system. A tropical depression could form from it around the middle of the week while it moves west-southwestward and then westward. See the Special Features section above for more details on both these systems. $$ Aguirre