AXPZ20 KNHC 270244

0405 UTC FRI MAY 27 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 0215 UTC.


The monsoon trough axis extends from 09N84W to 08N88W to 10N100W to low pres near 10N116W 1011 mb to 08N123W. ITCZ axis extends from 08N123W to 07N130W to 08N140W. Scattered moderate to isolated strong convection is seen within 180 nm south of the axis between 84W and 87W...also between 96W and 103W, and within 60 nm of the axis between 90W and 94W. Scattered moderate convection is within 60 NM of the axis between 127W and 129W.


High pressure centered well north of the area extends a ridge southeastward to 32N133W to 26N127W to near 20N111W. High pressure is present roughly north of 14N and west of 112W. Scatterometer data from Thursday afternoon showed fresh NE winds north of the ITCZ to 20N between 122W and 135W. The data also showed a very narrow swath of fresh to strong NE winds within 60 nm northwest of the low near 10N116W. The trough is moving west about 15 kt. The trough and its associated winds and seas will exit 140W Fri morning.

Weak low pressure of 1011 mb is embedded along the monsoon trough with a mean center near 10N116W. Latest satellite imagery shows that the low remains is elongated east to west. The imagery shows recently developed scattered moderate to isolated strong convection within 150 nm of the low in the northwest quadrant. Scattered moderate convection is within 120 nm of the low in the northeast and southeast quadrants. The 1748Z Ascat pass from Thursday afternoon showed a very narrow swath of fresh to strong NE winds within 60 nm northwest of the low.

Global model guidance suggests that the low will remain weak with disorganized convection as it slowly moves west-northwestward through late Friday. The low is forecast to begin to become somewhat more organized in its cloud/convective structure late Friday into Saturday as it passes 120W...all while strong upper level winds decrease. The strong high pressure north of the area is forecast to weaken and shift south during the next 48 hours.

Near gale to gale force NNW winds along the California coast are expected to produce an area of N swell that will sweep south of 32N Fri night and affect north-central waters N of 28N between 122W and 130W through Saturday. An area of seas to 8 feet in south swell located from 10N to 13N between 124W and 127W based on recent altimeter data is forecast to subside to just below 8 feet by early on Friday. Otherwise, rather benign marine conditions are expected to prevail across the remainder of the forecast area through Sun.

$$ Aguirre