000 AXPZ20 KNHC 230257 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 0405 UTC Tue Aug 23 2016 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 0230 UTC. ...SPECIAL FEATURES... Tropical Storm Kay is centered near 22.0N 118.0 at 23/0000 UTC or about 452 nm west of the southern tip of Baja California moving west or 270 degrees at 7 knots. The estimated minimum central pressure has risen to 1004 mb, with maximum sustained wind speeds 35 knots with gusts to 45 knots. Latest satellite imagery shows that the overall cloud pattern and convective structure of Kay continues to weaken. Cold cloud tops continue on the warming trend. Only scattered moderate convection is within 90 nm of the center in the northwest quadrant. Kay is forecast to forecast to weaken to a tropical depression by 12Z on Tuesday per the latest NHC advisory, then weaken further to a post-tropical remnant low by late Tuesday night, and dissipate on Thursday. Please read the latest NHC forecast/advisory under AWIPS/WMO headers MIATCMEP2/ WTPZ22 KNHC for more details, and the latest public advisory MIATCPEP2/WTPZ32 KNHC, for more details. Tropical wave axis is along 98W from 08N to 15N moving westward at 10 to 15 kt. Low pressure of 1009 mb is along the wave near 10N98W. Both of these features are part of a broad area of low pressure. Scattered moderate to isolated strong convection is within 120 nm southeast quadrant of the low. Scattered moderate convection is within 60 nm west of the wave. An Ascat pass from 1546Z Monday afternoon displayed an area of strong east to southeast winds east of the wave and low to near 95W with seas of 6 to 8 ft. This system is forecast to reach near 102W by Tuesday evening. Model guidance suggests that the system could be identified as low pressure near 14N110W by early Wednesday evening with related seas building to around 10 ft. The guidance also indicates that atmospheric conditions are favorable for development of this system through the next 48 hours. ...TROPICAL WAVES... Tropical wave axis along 90W north of 09N moving westward at 10 to 15 kt. Only isolated weak showers and thunderstorms are noted within 60 nm of the wave axis. Tropical wave axis is along 118W from 06N to 15N moving westward at about 15 kt. Scattered moderate to isolated strong convection is confined to the southern portion of the wave in the monsoon trough region within 60 nm west of the wave axis from 06N to 10N. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough axis extends from 10N85W to 10N92W to low pressure near 10N98W 1009 mb to 10N109W to low pressure near 10N112W 1008 mb to 09N121W to 10N134W. The ITCZ extends from 10N134W to beyond 08N140W. Scattered moderate to isolated strong within 180 nm south of the axis between 114W and 117W. Scattered moderate convection is within 120 nm south of the axis between 107W and 111W. Scattered moderate convection is within 120 nm south of the axis between 119W and 121W. ...DISCUSSION... OFFSHORE WATERS WITHIN 250 NM OF MEXICO... Tropical Storm Kay has moved west of the forecast area. Light to moderate winds prevail over much of the area in a relatively weak pressure pattern, which will persist into early next week. Combined seas of 4 to 6 feet will subside gradually during the next few days. The Gulf of Tehuantepec: The tight gradient behind the tropical wave along 98W in combination with nocturnal drainage flow into the Gulf will bring north to northeast winds of 20 to 25 knots into the Gulf with seas building to 8 ft beginning on Tuesday morning. These winds will briefly diminish to 15 to 20 kt on Tuesday afternoon, then start up again late Tuesday night into Wednesday with seas building to 10 ft Wednesday morning. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... Winds will pulse into the Gulf of Papagayo during the next few nights...peaking near 25 kt during the late night and early morning hours and weakening to 20 kt during the late afternoon and early evening hours. Elsewhere, Light to moderate winds will prevail on either side of the monsoon trough with seas in the 4 to 6 foot range. ELSEWHERE... Low pressure of 1008 mb along the monsoon trough near 10N112W. Latest satellite imagery shows scattered moderate isolated strong convection is within 60 nm of the low in the southeast quadrant. The Ascat pass from 1728Z Monday afternoon showed a swath of strong south to southwest winds south of the low, and within the monsoon trough region from 07N to 09N between 110W and 115W. Seas of 6 to 8 ft are associated with these winds. This low is forecast to move in a general west-northwest direction to near 10N115W by early Tuesday evening, and to near 11N121W by early Wednesday evening with some potential for gradual development. The strong south to southwest winds to its south will expand westward as the low with seas possibly reaching near 10 ft late Tuesday night or on Wednesday. Elsewhere, weak high pressure of 1018 mb is centered near 32N126W. The resulting weak pressure gradient is maintaining generally light to gentle winds with sea heights in the range of 4 to 6 feet, except near the vicinity of Kay where the gradient between the cyclone and the ridge is keeping winds of higher speeds, in the moderate to fresh range with seas of 5 to 8 ft there. These winds and seas will shift westward as near the cyclone as it weakens to a remnant low over the next couple of days. $$ Aguirre