Skip Navigation Links
NOAA NOAA United States Department of Commerce

Eastern North Pacific Tropical Weather Discussion

AXPZ20 KNHC 270244

TROPICAL WEATHER DISCUSSION                                  
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.