000 AXPZ20 KNHC 110310 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 231 UTC Fri Sep 11 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 0220 UTC. ...SPECIAL FEATURES... A 1010 mb low is centered along the monsoon trough near 13N105W. Active convection continues across this area in association with the low and a tropical wave along 107W, where scattered moderate to strong convection extends from 08.5N between 104W and 114W northeastward to the Mexican coast between 100W and 106W. An afternoon scatterometer pass showed a very broad cyclonic circulation about the low and monsoon trough, with peak winds around 20 kt and seas 7-8 ft in the SW quadrant 100 to 200 NM from the center. Environmental conditions appear conducive for development of this system, and a tropical depression could form over the weekend or early next week while the system moves west- northwestward at 10 to 15 kt away from the coast of Mexico. The system has a medium chance of developing over the next two days. For more information, see the latest Tropical Weather Outlook at https://hurricanes.gov. ...TROPICAL WAVES... A tropical wave axis is along 81W, north of 03N into Central America, moving westward around 10 kt. No significant convection is noted in association with this wave across the eastern Pacific waters, while small clusters of moderate convection are noted over the southwest Caribbean waters. A tropical wave axis is along 107W, from 04N to 18N, moving west around 10 kt. Convection associated with this wave is described above associated with the 1010 mb low pressure system. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough axis extends from 10.5N76W TO 08N82W TO low pressure near 13N105W 1010 mb to another low pressure near 18N115W 1010 mb to 11N132W to beyond 12N140W. Widely scattered moderate isolated strong convection is within 120 nm either side of the trough between 85W and 101W. Scattered moderate to strong convection is noted from 08.5N between 104W and 114W NE to the Mexican coast between 100W and 106W. Scattered moderate to strong convection is noted within 90 nm south of the trough west of 134W. OFFSHORE WATERS WITHIN 250 NM OF MEXICO... See Special Feature discussion of low at 13N105W. A stationary front extending across the N Gulf of California will weaken tonight. Generally tranquil marine conditions are expected across the offshore waters for the next several days. However, if the low at 13N105W does strengthen into a tropical cyclone, forecast winds and waves will be substantially increased across the Mexican offshore zones. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, and WITHIN 750 NM OF ECUADOR... Tranquil conditions should prevail for the next several days with light to gentle winds north of the monsoon trough along about 10N, and gentle to moderate S to SW winds south of the monsoon trough. No significant long-period swell is expected to impact these waters during the next several days, although small swell will continue to impact the waters for the next several days. REMAINDER OF THE AREA... Low pressure of 1010 mb is centered near 18N115W. Scattered moderate convection is noted across this area from 15.5N to 21N between 114.5W and 118W. A scatterometer pass this afternoon indicated a small cyclonic circulation with maximum winds of 20-25 kt in the W semicircle. Some development of this system is possible during the next few days before it interacts with, and possibly becomes absorbed by, a larger weather disturbance to its east discussed in the Special Feature section. High pressure dominates the waters north of 20N, west of 120W. Gentle to moderate NE trades continue north of the monsoon trough axis with seas 5-7 feet. Moderate to fresh S flow persists south of the trough with 5-7 ft seas. Long-period SW swell is present east of 120W, contributing to total seas of 6-8 feet near the equator. Seas will slightly subside Fri through Tue. $$ Stripling