000 AXPZ20 KNHC 202204 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 2205 UTC Sat Aug 20 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 1800 UTC surface analysis and satellite imagery through 2145 UTC. ...SPECIAL FEATURES... Tropical Storm Kay was is centered near 20.3N 113.1W at 20/2100 UTC or about 220 nm southwest of the southern tip of Baja California moving northwestward, or 320 degrees at 5 knots. The estimated minimum central pressure was 1000 mb. Maximum sustained winds are 45 knots with gusts to 55 knots. Latest satellite imagery shows an area of stable air, indicated by the stratus type clouds, entraining into the western portion of its circulation. Scattered strong convection is within 90 nm of the center in the southwest quadrant. Scattered moderate convection is elsewhere within 90 nm in the southeast quadrant, within 180 nm in the southwest quadrant and within 120 nm in the northwest quadrant. Kay is forecast to maintain its intensity until early Sunday morning before it begins to weaken over cooler sea surface temperatures. The latest NHC advisory has Kay weakening to a minimal tropical storm intensity with wind speeds of 35 knots on Monday, to a tropical depression early on Tuesday morning, then become a post-tropical remnant low early on Wednesday morning. 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 WAVES... The southern portion of a tropical wave axis that extends from the western Caribbean Sea along 86W and south to Honduras reaches south to near 09N. It is moving westward at about 15 kt. Weakening isolated moderate convection is within 120 nm west of the wave axis from 09N to 11N. This wave is forecast to reach near 90W early on Sunday, and to near 95W on Monday with its northern portion pushing through the Gulf of Tehuantepec and vicinity. The axis of a tropical wave is along 108W/109W from 08N to 17N. Low pressure of 1011 mb is on the wave axis near 11N109W. Scattered moderate convection is noted from 08N to 14N between 108W and 110W. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough axis extends from 09N79W to 09N99W to low pressure near 11N109W 1011 mb. Scattered moderate isolated strong convection is within 120 nm south of the axis between 97W and 106W, and within 60 nm south of the axis between 106W and 109W. Scattered moderate convection is within 180 nm north of the axis between 106W and 109W. ...DISCUSSION... OFFSHORE WATERS WITHIN 250 NM OF MEXICO... Tropical Storm Kay continues to impact the waters southwest of the tip of Baja California, and it is described in detail in the special features section. Light to moderate winds prevail outside of Kay in a relatively weak pressure pattern, which will persist into early next week. Combined seas of 4 to 7 feet outside of Kay will subside gradually early next week. The Gulf of Tehuantepec: northerly offshore winds will continue to pulse to fresh levels during the late night and early morning hours with nocturnal drainage flow. The northerly flow may briefly pulse to moderate to strong intensity late Monday night into Tuesday with passage of the forecast tropical wave as described above. Model guidance then suggests that the northerly flow may increase further to fresh to strong on Wednesday and Thursday of next week as high pressure ridging from the Gulf of Mexico presses southwest across southeastern Mexico. Scattered moderate convection is occurring from 21N to 23N between 107W and 108W due to a shortwave trough lifting northeastward across the southern portion of the Gulf of California into northwest Mexico. This activity is expected to continue into tonight, and may be attendant by gusty winds. Similar activity is occurring just inland Mexico from near Acapulco to Los Mochis. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... Offshore winds will pulse to fresh levels in the Gulf of Papagayo and adjacent areas during the late night and early morning hours on Tuesday and on Wednesday. Light to moderate winds will prevail on either side of the monsoon trough. Combined seas of 4 feet to 7 feet will slowly subside through Monday as supporting long period south-southwest swell decays. Seas are expected to be about 5 to 6 ft downstream of the Gulf of Papagayo through Monday. A tropical wave, currently along 86W, is forecast to reach 90W early on Sunday and near 95W on Monday. ELSEWHERE... High pressure of 1030 mb centered northwest of the area extends a weakening ridge southeastward to 32N140W and to near 23N123W. The resulting weak pressure gradient is maintaining generally light to gentle winds with seas in the 4 to 6 ft range. These general conditions will prevail into Monday. $$ Aguirre