000 AXPZ20 KNHC 151605 RRA TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 1605 UTC Wed Jun 15 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 1200 UTC surface analysis and satellite imagery through 1545 UTC. ...TROPICAL WAVES... A tropical wave axis is along 82W from 06N to 15N, moving westward near 15 kt. The wave axis extends from the southwestern Caribbean Sea, across northern Panama, and into the eastern Pacific Ocean. Scattered moderate convection is noted within 120 nm w of the wave from 06N to 08N. ..INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough axis extends from 10N88W northwest to 14N100W to low pressure near 15N105W 1009 mb to 11N111W to 11N123W where scatterometer and model data suggest it transitions to the ITCZ axis to 08N123W to beyond 06N140W. Scattered moderate to isolated strong convection is south of the monsoon trough within 60 nm of a line from 07N91W to 08N96W, within 120 nm north of the axis between 119W and 127W, and within 120 nm south of the axis between 127W and 135W. ...DISCUSSION... From 15N northward and from 120W eastward: A northwest to southeast oriented surface ridge is present over this section of the area. A 1009 mb low pressure center is near 15N105W with a trough extending northward to 18N105W. The low is associated with a broad area of low pressure observed to the south of central Mexico from 11N to 18N between 100W and 108W. Only small clusters of scattered moderate to isolated strong convection are noted within 120 nm of the low. The low and broad low pressure area is forecast to gradually move west- northwestward over the next couple of days with the possibility of some slow development. The surface ridge will retract from southeast to northwest through Friday as the low pressure area advances across this part of the area. Models indicate that mainly moderate winds will prevail through the next 48 hours, with the exception of occasionally fresh offshore winds off the Baja California peninsula. Combined seas of 5 to 7 feet will build to 8 to 9 feet to the north of 24N and to the west of the Baja California peninsula tonight through Friday due to the arrival of fresh northwest swell. The Gulf of California: a surface trough will linger from northwest to southeast across the Gulf resulting in variable winds dependent on either side of the trough. The wind speeds will be light to moderate with seas generally 2 feet or less away from the entrance of the Gulf. Little change is forecast through the end of the week. The Gulf of Tehuantepec: mainly light onshore flow is anticipated, shifting to offshore during the overnight hours with nocturnal drainage flow through Friday with seas in the general range of 6-7 feet. From 15N southward and from 120W eastward: As described above a 1009 mb low pressure center is located near 15N105W. The low is forecast to slowly move off to the west- northwestward through Friday. Numerous moderate to strong convection is seen to the east of the low from 10N to 15N between 100W and 103W. The low and broad low pressure area is forecast to gradually move west and northwest during the next 48 hours. Expect mainly gentle to moderate winds on either side of the monsoon trough, with primarily a westward/onshore component, except during the overnight hours when nocturnal drainage flow will result in offshore winds. Cross-equatorial southwesterly swell will continue to propagate to the northeast with combined seas of 6 to 9 feet through Thursday. These seas are forecast to slowly subside through late Thursday into Friday as the culprit swell decays. Elsewhere to the west of 120W: A surface ridge remains in the northern waters. The difference in pressure between the ridge and the lower pressure in the vicinity of the intertropical convergence zone will maintain moderate to fresh trade winds to the north of the ITCZ through Friday. The surface ridge will weaken gradually through the end of the week as a weak cold front or remnant trough slips into the far northern waters and stalls as depicted by the models. $$ Aguirre