000 AXPZ20 KNHC 040233 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 0405 UTC Mon Sep 4 2017 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 0215 UTC. ...TROPICAL WAVES... A tropical wave axis is along 105W/106W from 12N to 19N, moving westward at 10 to 15 kt. Scattered moderate isolated strong convection is noted to the east of the wave N of 18N and E of 106W to inland Mexico. Scattered moderate convection is within 30 nm of 18N107W. ..INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough axis from NW Colombia to across central Costa Rica to 10N86W to low pressure at 10N92W 1010 mb to 12N99W to low pressure near 12N102W 10111 mb to 13N111W to 13N122W to low pressure near 16N127w 1014 mb to 14N140W. Scattered moderate isolated strong convection is seen within 240 nm S of the axis between 86W and 90W, also S of the axis within 60 nm of a line from 06N92W to 06.5N95W, within 30 nm of a line from 06.5N95W to 08N97W and also along the coast of Costa Rica. ...DISCUSSION... OFFSHORE WATERS WITHIN 250 NM OF MEXICO... The remnant low of Lidia is analyzed off the coast of Baja California Norte at 31N118W with a pressure of 1009 mb. An AscatB pass from Sunday afternoon depicted lingering strong SE to S winds within 90 nm of the low in its NE quadrant. Maximum seas are possibly up to 8 ft with these winds. The low will weaken as it continues to move northwestward tonight into Monday reaching near 32N120W with a pressure of 1012 mb by early Monday afternoon. At that time, the strong SE to S winds are forecast to diminish to the gentle to moderate range, with seas 8 ft lowering to around 5 ft. The eastern periphery of the ridging over the NW portion of the area will then protrude eastward over these waters in the wake of the low and persist through Tuesday. The associated gradient should support gentle to moderate NW winds, along with seas of 3 to 5 ft across these waters. Farther south, fresh overnight gap winds are possible through the Gulf of Tehuantepec tonight and then again late this week with seas building to near 7 ft. Light to gentle winds and seas of 4 to 6 ft will prevail elsewhere. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... Gulf of Papagayo: A moderate to locally fresh offshore breeze will begin tonight, then shift to W of the Gulf from 10N to 12N between 88W and 92W by Tuesday afternoon. Otherwise, light and variable winds are expected N of the monsoon trough through Tuesday, while moderate to locally fresh southerly winds are expected S of the monsoon trough with seas of 4 to 6 ft over the entire area. Later in the week beyond 48 hours, seas are forecast by wavewatch guidance to build to 5 to 7 ft over mainly the most western portions of the 250 nm range as long period S to SW swell propagates through those waters. REMAINDER OF THE AREA... A 1018 mb high analyzed at 25N133W extends a ridge to near 22N119W. Another 1018 mb high is centered to its N at 33N133.5W. The high at 25N133W will shift northwestward to near 27N136W by Monday afternoon, but the associated ridging will be relatively weak. The pressure gradient between the ridging and lower pressure associated with the monsoon trough will maintain generally light to gentle winds trades N of about 14N and W of 121W, except for light to gentle anticyclonic flow around the anticyclone and gentle to moderate NW to N winds to the NE of the ridge. Seas N of of the monsoon trough and ITCZ axis are expected to be in the 4 to 6 ft range through Tuesday. Moderate to fresh SW winds are expected to the S of the monsoon trough through Tuesday. Long period SE cross- equatorial swell producing combined seas of 7 to 9 ft will continue to propagate as far N to near 06N through Monday. The swell is then forecast to decay early on Tuesday allowing for seas to subside to below 8 ft Tue. Later in the week beyond 48 hours, combined seas from SE swell and southerly winds to the S of the monsoon trough are forecast to build combined seas to 8 ft S of around 09N between 105W and 125W by Friday. $$ Aguirre