000 AXPZ20 KNHC 110932 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 1205 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 0600 UTC surface analysis and satellite imagery through 0900 UTC. ...SPECIAL FEATURES... A 1008 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 108W-109W, where scattered moderate to strong convection extends from 08N between 104W and 114W northeastward to the Mexican coast between 102W and 107W. Recent scatterometer data showed a very broad cyclonic circulation about the low and monsoon trough, with peak winds around 20 kt and seas 6-7 ft between the low and the coast of western Guerrero, and winds to around 20 kt in the SW quadrant 100 to 200 NM from the center, where seas are 6-8 ft. 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 and 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 is along 83W-84W, north of 03N into Central America, moving westward around 10 kt. Scattered moderate to strong nocturnal convection is occurring ahead of the wave and has moved W-SW and over water, extending within 180 nm of the coast between northern Costa Rica and El Salvador. Small clusters of moderate convection are also noted over the southwest Caribbean waters. A tropical wave axis is along 108W-109W, from 04N to 18N, moving west around 10 kt. Convection associated with this wave is described above associated with the 1008 mb low pressure system. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough axis extends from 10.5N74W to 09N80W to low pressure near 13N105W 1008 mb to another low pressure near 18N115W 1009 mb to 11N133W to beyond 12N140W. Widely scattered moderate isolated strong convection is within 180 nm either side of the trough between 89W and 104W. Scattered moderate to strong convection is noted from 08N between 104W and 114W NE to the Mexican coast between 102W and 107W, within 180 nm of the coast between 84W and 90W, and within 180 nm south of the trough west of 135W. 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 through morning. Generally tranquil marine conditions are expected across the offshore waters for the next several days as a weak pressure gradient prevails. However, the low at 13N105W is expected to gradually become better organized and will likely increase winds and seas across the outer waters from offshore of Manzanillo shifting west-northwest to the Clarion Island area. 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 1009 mb is centered near Clarion Island near 18N115W. Scattered moderate convection is noted around the NW periphery of the low, from 18N to 21N between 114W and 118W. Recent scatterometer data indicated a broad and weak cyclonic circulation with maximum winds of 15 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 the larger weather disturbance to its east discussed in the Special Feature section. Weak high pressure of 1021 mb centered near 31N134W 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 subside slightly Fri through Tue. $$ Stripling