AXPZ20 KNHC 310329

0405 UTC TUE MAY 31 2016

Corrected discussion section to include low near 09N105W

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.


A tropical axis extends from 11N94W to 06N92W moving westward at 13 kt. Clusters of scattered moderate to isolated strong convection continue to be quiet active within 180 nm east of the wave axis. Low pressure may form along the wave as it moves to near 95W/96W late on Tuesday.

A tropical wave extends from the far southwestern Caribbean Sea southeast across central Panama...to across the Gulf of Panama and to northwest Colombia. It is moving westward at 10-15 kt. The wave is helping to produce scattered showers and thunderstorms over northern Panama and over portions of northwest Colombia.


The monsoon trough axis extends from 14N85W to 10N100W to 09N105W to low pressure near 09N110W 1012 mb to 11.5N115W to low pressure near 12N118W 1010 mb to 08N129W, then transitions to the ITCZ axis from 08N129W to beyond 09N140W. Scattered moderate to isolated strong convection exists within 180 nm south of the axis between 98W and 108W.


The subtropical ridge prevails over northern waters N of about 15N and west of 115W. A cold front is within about 230 nm to the northwest of the area. It is being blocked by high pressure north of the area, and is expected to become stationary west of 140W during the next 36-48 hours. A persistent low pressure area near 12N119W of 1010 mb is moving southeastward. Latest satellite imagery shows a cluster of scattered moderate convection within 60 nm of the low in its northeast quadrant. An Ascat pass from 1804Z Monday showed northerly winds 15 to 20 kt on the northwest periphery of the low. The low is forecast to reach nears 11N117W by Tuesday evening, and to near 10N116.5W by Wednesday evening. The same Ascat pass revealed gentle trade winds over most of the area north of the convergence zone outside the vicinity of the low, and mainly light southerly winds to the south. A weak low pressure area is near 09N110W. This low remains disorganized for the time being. It is forecast to reach near 09N112W by Tuesday evening, and to near 10N114W by Wednesday evening. The pressure gradeint is forecast to increase to the southeast of this low with strong south to southwest winds developing from 05N to 06N between 109W and 111W late on Tuesday, and reach westward to near 115W by Wednesday evening with seas building to the range of 8 to 10 ft. South to southwest swell moving through much of the south/central and southeast portions of the area is producing seas of 8 to 9 ft. This swell is forecast by wavewatch/swell guidance to slowly dissipate through the next 48 hours, with the seas of 8 to 10 ft associated with the aforementioned area of strong south to southwest winds forecast to become the main marine issue at that time.

$$ Aguirre