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000
FXUS66 KPQR 160946
AFDPQR

Area Forecast Discussion
National Service Portland OR
245 AM PDT Tue Jul 16 2019

.SYNOPSIS...Plenty of clouds around the region this week, with some
chance of showers. Highest chance of precipitation will be later Wed
night into Thu morning as a decent front moves across the region.
Unsettled weather continues on Fri into early Sat, then rest of next
weekend looks mild and dry.
&&

.SHORT TERM...Today through Thursday...Onshore flow over the region
continues, with plenty of clouds. Still have rather deep marine layer
over the region, which should help support spotty drizzle this
morning, mainly along the coast, and inland against the Cascades
foothills.

Remnants of weak surface low still just off the Oregon coast this
morning. With bit of instability still over the region, will keep a
minor chance of showers (PoPs of 20 pct or less) for today.

Another upper disturbance off the Alaskan panhandle will slide
southeast tonight and Wed, then shift inland over Washington Wed
night and Thu. During the time, the low will bring a slowly moving
warm front across the region later Wed, followed by a cold front
later Wed night. Currently, there is decent slug of mid and high
level moisture over the north Pac, roughly along 50 deg N, and out
between 140 and 160 deg W. Models continue to show this moisture
getting entrained into the prior mentioned frontal system. All said,
will see light rain develop along the coast Wed afternoon with the
warm front, while most all others stay mostly dry. However, with the
cold front arriving, rain along the coast will gradually spread
southward and inland Wed night.

Though not a big rainmaker, likely to see 0.15 to 0.30 inch in the
Willapa Hills, northern Coast Range, and Cascades as far south as Mt
Jefferson. Generally less than 0.10 inch elsewhere.

Models fairly insistent that the front will shift east of the
Cascades early Thu am, with rain quickly transitioning to showers.
Air mass not all that unstable behind the front, so dynamic forcing
not impressive. Will keep with decreasing chance of showers,  for mid
to late morning through early evening on Thu, but have feeling even
that may be too much PoP for most areas.           /Rockey

.LONG TERM...Thursday night through Saturday...Few showers will
linger into Thu evening, especially over the higher terrain. Cooler
temperatures will be most noticeable at night due to the drier air
mass, and some outlying areas may dip into the upper 40s. Now appears
the extended models, both GFS and ECMWF, are swinging yet another
upper low out of the coastal British Columbia area and into the Pac
NW for Fri. This will bring more clouds, along with some minor
chance of showers to the region, and locally breezy west to
northwesterly winds over the higher terrain. Then, high pres build
over the weekend, with milder and drier weather.     /Rockey

&&

.AVIATION...A weak upper trough over the area will continue next
few day with somewhat unsettled conditions. Light onshore flow
will continue to bring cloudiness in the area. Inland...expect
VFR conditions to prevail with cigs 4000-7000 ft. But there will
be occasional MVFR cigs around 2500-3000 ft through about 16-18Z.
At the coast...MVFR to IFR conditions likely to persist through
18-20Z, but some of the guidance shows conditions may not improve
above MVFR. But in either case increasing onshore flow ahead of
the front for Wed, will bring MVFR conditions again after about
04Z Wed.

KPDX AND APPROACHES...MVFR cigs 2500 feet are filling in the
areas. Cigs should then improve to VFR by 18Z with a BKN deck
with cigs 4000 to 5000 feet persisting through Tue evening.

&&

.MARINE...A ridge of high pressure over the waters shifts inland
tonight ahead of a front arriving Wednesday. Models have been
fairly consistent with the timing of the front, moving ashore
Wed afternoon. But differ on the strength of the winds, for now
only the NAM based models are indicating wind gusts to around 25
kt over the northern zones. Based on this have held winds below
advisory criteria and will see if other models come on board with
NAM solution. High pressure begins to rebuild offshore on
Thursday and strengthens for the weekend. This will result in a
return to northerly winds through at least early next week. Gusts
25-30 kt can be expected for the weekend with the strongest winds
beyond 10 NM offshore.

Seas start in the 2 to 4 ft range, then build to around 7 feet
Thursday morning. The larger seas are a product of the increased
wind wave height from the short wave system that moves through
Wednesday night into Thursday but also from a 6 ft swell out of
the NW that will be the dominant swell throughout the forecast
time period.                   /mh/BPhillips

&&

.PQR WATCHES/WARNINGS/ADVISORIES...
OR...None.
WA...None.
PZ...None.
&&


$$

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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
commonly referred to as the forecast area.