000 AXPZ20 KNHC 120928 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 1005 UTC Sat Sep 12 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 0830 UTC. ...SPECIAL FEATURES... A 1006 mb low is centered along the monsoon trough near 15.5N109.5W, and anchors the eastern end of an elongated cyclonic circulation in the lower atmosphere that extends W-NW to a second surface low of 1009 mb near 17.5N118.5W. A large area of active weather is persisting south and west of the 1006 mb, where scattered moderate to strong convection is occurring from 09N to 19.5N between 107W and 119W. Recent ASCAT data depicted a very broad cyclonic circulation about the low between 104W and 113W with peak winds around 20 kt and seas 6-7 ft between the low and the coast of western Guerrero. Strong westerly monsoonal winds of 20 to 30 kt were depicted south of the low and the monsoon trough between 108W and 119W, where seas are 7-9 ft. Environmental conditions appear conducive for development of this system, and a tropical depression is likely to form over the weekend or early next week while the system moves west- northwestward away from the coast of Mexico. The system has a high 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 extends along 87W north of 03N to across Central America, moving westward at 10-15 kt. Scattered moderate to strong convection ahead of the wave has been occurring over land and is shifting over water, extending from 10N to the coast between 84W and 96W. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough axis extends from 10.5N73W to 09N83W to low pres near 15.5N109.5W 1006 MB to low pres near 17.5N118.5W 1009 MB to 11N140W. Scattered moderate isolated strong convection is noted N of 06N between 78W and 85W. Scattered moderate to strong convection is noted from 07N to 14N between 87W and 96W, from 08N to 11N between 100W and 104W, from 09N to 19.5N between 107W and 119W. Scattered moderate isolated strong convection is noted from 11N to 14N between 119W and 140W. Scattered moderate isolated strong convection is within 180 nm across the NW semicircle of low pressure 1009 mb near 18.5N118.5W. OFFSHORE WATERS WITHIN 250 NM OF MEXICO... See Special Feature discussion of low near 14N107W. Generally tranquil marine conditions are expected across the offshore waters for the next several days as a weak pressure gradient prevails. However, the low pressure near 15.5N109.5W is expected to gradually become better organized and will increase winds and seas across the outer waters from offshore of Manzanillo and Cabo Corrientes, shifting west-northwest to the Clarion Island area through the weekend. Modest pulses of northerly gap winds to near 20 kt can be expected each of the next few nights across the Gulf of Tehuantepec, increasing seas to 6 ft. 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 south to southwest 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 southwest of the Clarion Island near 17.5N118.5W. Scattered moderate to strong convection is within 180 nm of the low in the NW quadrant. Recent ASCAT data indicated a broad and weak cyclonic circulation consisting of gentle to moderate winds across the east semicircle and 15-20 kt winds within about 210 nm of the low in the western 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. High pressure of 1021 mb centered near 31N131W dominates the waters north of 20N, west of 120W. Gentle to moderate northeast trades continue north of the monsoon trough axis with seas 5-7 feet. Moderate to fresh south flow persists south of the trough with 5-7 ft seas. Long-period south to southwest swell is present east of 120W, contributing to combined seas of 7-8 feet near the equator. Seas will subside slightly through Tue, however wave model guidance suggests that new south to southwest will be moving through waters south of the Equator and east of 120W during the early to middle part of next week. $$ Stripling