AXPZ20 KNHC 290153 CCA

2205 UTC SAT MAY 28 2016

Corrected Discussion section

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.


The monsoon trough axis extends from 10N84W to 11N96W to 13N110W to low pressure near 10N122W 1009 mb to 07N126W. ITCZ axis extends from 07N126W to beyond 05N140W. Scattered moderate to isolated strong convection is within 120 nm s of the axis between 93W and 97W, and south of the axis within 30 nm of a line from 09.5N106W to 09N111W. Scattered moderate convection is within 60 nm of the axis west of 136W.


High pressure centered N of the area extends a ridge southeastward to 32N133W to 25N127W to near 20N120W. High pressure covers the area north of 15N and west of 115W. A weak low of 1009 mb is analyzed near 10N122W. Widely scattered showers and isolated thunderstorms are noted mainly within 120 nm east semicircle of low. Global model guidance continues to keep the low in the same general area through Sunday morning with some development before it begins to lift in a north to northeasterly direction through Monday. Strong south to southwest winds are expected to to the southeast of the low from 10N to 12N between 117W and 120W on Sunday with seas building to 10 feet. A tight pressure gradient between the low and the ridge over the northern and central waters should allow for strong northeast winds to develop in the northwest quadrant of the low on Sunday with seas of 8 to 9 ft. The low is forecast to weaken Sunday night and Monday with associated winds decreasing to 20 kt and seas of 8 ft in south to southwest swell mixed with a secondary swell component from the north over an area roughly south of 16N between 114W and 127W. The aforementioned high pressure north of the area is forecast to weaken as it slides eastward during the 48 hours.

East of 125W...satellite water vapor imagery shows plentiful deep atmospheric moisture present underneath a mid-level ridge roughly along 14N. The southern portion of an upper level trough that stretches from central Baja California to near 12N126W is providing lift for the deep moisture. This has resulted in the development of clusters of scattered moderate to isolated strong convection near and south of the monsoon trough segment between 105W and 111W. The trough is forecast to shift east of the area Sunday. Ascat data from this afternoon depicted an area of fresh northeast winds west of 136W between 09N-12N, and moderate trades N of the convergence zone west of 125W. Mainly gentle winds prevail elsewhere across the basin. Elsewhere, near gale force N-NW winds along the California coast have produced an area of 7-8 ft N swell in north/central waters between 123W and 129W. Cross-equatorial S-SW swell will affect the area south of the equator between 104W and 120W. The swell is forecast to merge with the area of elevated sea heights associated with the low near 10N122W to produce a fairly large area of 6-8 ft seas in south-central waters by late Sunday. Mostly benign marine conditions are expected to prevail across the remainder of the forecast area through Tuesday.

$$ Aguirre