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National Weather Service Area Forecast Discussion for Long Beach, WA USA

fxus66 kpqr 230356

Area Forecast Discussion
National Weather Service Portland, OR or
855 pm pdt fri sep 22 2017

.synopsis...a ridge of high pressure over the eastern pacific will
gradually nose into the pacific northwest over the next several days.
weak disturbances topping the ridge will keep variable amounts of
clouds in the area into early next week, before the ridge builds
firmly inland and flow turns offshore late tuesday through the end of
next week.


.short term...tonight through monday...showers over the cascades and
foothills as well as the coast range this afternoon have dissipated
as an upper level low continues to push further east of the area.
with abundant surface moisture, light winds, and clearing skies,
expect another round of fog tonight and saturday morning. added
patchy fog to the columbia river gorge as winds there should be light
enough to support it. also adjusted pops down for the overnight
period based on trends and latest models. bowen

onshore flow and weak warm advection will bring a cloudy start
saturday, with perhaps sprinkles/light rain along coastal and coast
range areas. the upper ridge builds a little farther inland sunday,
and with the longer nights of fall, expect to see more in the way of
morning fog/clouds sunday morning, before giving way to partly to
mostly sunny skies. models show one more weak shortwave topping the
ridge late monday and monday night, keeping the ridge less than
pristine going into tuesday. thereafter, a different story as the
upper ridge builds strongly overhead while a thermal trough extends
northward along the coast. this is covered in the long term
discussion that follows. drb

.long changes. previous discussion follows...monday night
through saturday...ridge of high pressure will continue to build into
the area from the ne pacific. this will bring warmer temperatures
into the area. offshore winds are looking to start around tuesday
night. which will prevent nighttime clouds and fog from forming.
there is uncertainty in when the offshore winds will end, which makes
the temperature forecast for the end of next week more uncertain.


.aviation...vfr conditions across the area this evening.
satellite imagery at 03z showed considerable mid and high level
clouds across the area in north flow aloft. the south washington
coast starting to see ifr stratus forming and expect areas of ifr
to lifr to develop at kast and konp overnight. inland interior
valleys likely to see mvfr cigs develop late tonight. a weak
disturbance within the north flow aloft drops south along the
washington and north oregon coast sat morning. this feature may
produce some -dz or -ra along the coast and into the coastal
valleys, possibly reducing vis into the mvfr category. overall
flight conditions gradually improve sat afternoon.

kpdx and approaches...vfr conditions through at least 12z sat.
expect mvfr cigs to develop late tonight to around sunrise. look
for improvement to vfr late sat morning or early afternoon, but
there will be considerable mid-level clouds. weishaar


.marine...rather quiet on the marine front through early next
week. wind speeds will be 15 kt or less through tue morning.
models in general agreement showing a surface thermal low over
the n california and far s oregon coast tue afternoon. this
feature expands north tue night for the possibility of small
craft advisory level north wind. the thermal trough forecast to
remain along the coastline wed and wed night, then weaken thu.

seas have come down to around 6 ft this evening. guidance
suggests general 4-5 ft seas sat through early next week.


.pqr watches/warnings/advisories...



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this discussion is for northwest oregon and southwest washington
from the cascade crest to 60 nautical miles offshore. this area is

Information courtesy of the National Weather Service - NWS Portland...
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