AXPZ20 KNHC 300254

0405 UTC MON MAY 30 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.


An ill-defined tropical wave axis is analyzed along 85W north of 07N, moving westward at 10 to 15 kt. Clusters of scattered moderate to isolated strong convection are noted within 60 nm west of the axis. Scattered moderate convection is seen east of the wave within 30 nm of 07N82W. The pressure gradient near this wave will remain weak during the next 48 hours as the wave moves further west through a broad area of low pressure. Surface signature of the wave is expected to be rather subtle...if detected...through Tuesday.


The monsoon trough axis extends from 10N86W to low pressure near 09N94W 1010 mb to 09N100W to 09N107W to 13N113W to low pressure near 13N120W 1010 mb to 09N127W to 09N135W. The ITCZ axis extends from 09N135W to beyond 07N140W. Scattered strong convection is within 30 nm of the axis between 113W and 114W. Scattered moderate to isolated strong convection exists within 30 nm of the axis between 116W and 118W.


High pressure covers the area to the north of 15N west of 112W with a ridge axis roughly along 32N133W to 26N127W to near 24N116W. The very tight pressure gradient from the past few days that was just north of the northeastern portion of the area has weakened. N swell that has been ushered into the north-central waters from this gradient are gradually subsiding north of 27N between 122W and 128W with resultant seas of 8 feet. The swell energy is expected to dissipate by Monday afternoon, with seas subsiding to 6 to 7 feet there.

Ascat data from Sunday afternoon depicted generally gentle to moderate northeast to east winds north of the convergence zone west of 114W, and light to variable winds east of 114W. Light to moderate southerly winds were indicated south of the monsoon and ITCZ zones.

A 1010 mb low pressure center is analyzed near 13N120W. Latest satellite imagery shows a diminishing trend from earlier deep convection observed in association with the low. The imagery is presently revealing scattered moderate type convection within 60 nm of the low in the west quadrant. The low is forecast to move northeast through Monday morning, then to the southeast thereafter while weakening. Strong northeast winds in the northwest quadrant of the low with seas of 8 to 10 ft are forecast to diminish to 15 to 20 kt by late Monday afternoon. A small area of strong southwest winds to the southeast of the low from 11N to 12N between 120W and 121.5W are forecast to also diminish on Monday. The main marine issue will be attributed to an extensive swath of southern hemispheric south to southwest swell that will slowly subside as it sweeps through the south/central waters into early on Tuesday, and to much of the southeastern waters by late on Tuesday. A weak cold front is forecast by the Global models to approach the far northwest portion of the area late on Tuesday and stall. No significant impact is expected from this front on winds and seas in the far northwest waters.

$$ Aguirre