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fxus66 kpqr 270417 

Area forecast discussion
National Weather Service Portland or
916 PM PDT Wed Jul 26 2017 upper level trough approaches the area from the
northwest tonight for an increase of inland clouds Thursday morning.
Thursday will be the coolest day of the week with temperatures
peaking slightly below the seasonal normal. A gradual decrease of
marine clouds is expected Friday through the weekend for gradual


Short term...tonight through Saturday...forecast remains largely on
track this evening with only a few minimal changes required. After a
few thunderstorms moved along and near the Cascade crest in Lane
County this afternoon, all remaining storms are east of the Cascades
and generally weakening. A fairly widespread shield of stratus has
moved across the coastal waters and a more widespread intrusion of
marine air is expected to continue across the interior. Therefore,
introduced sky cover slightly earlier along the coast and intothe
coastal gaps, given satellite trends and surface and camera
observations. Additionally, added patchy fog to the coastal areas
starting sooner tonight, given the earlier onset from Lincoln City
down to Florence.

Another upper low is moving onto the British Columbia coast this
evening with a shortwave trough rotating around this upper low
approaching the Pacific northwest overnight. Approach the Pacific northwest
tonight. The combination of this approaching trough from the
northwest and the southern trough moving east will result in west
flow aloft developing across the region.

Clouds should clear in the afternoon Thursday, but a cloudier start
to the day and a cooler air mass will result in cooler inland
afternoon temperatures on Thursday. Expect afternoon high
temperatures across the interior to reach only the upper 70s to lower

The upper trough will continue to impact the region Friday for
another push of inland stratus. There may not be as much clouds
Friday morning as is expected for Thursday morning and the afternoon
inland temperatures on Friday may be a few degrees warmer, in the mid
80s. Models suggest that the upper level trough will split Friday
night as another upper low deepens over the NE Pacific. This will
send a portion of the upper trough south into California with an
upper ridge building over the Pacific northwest. A slightly shallower marine
layer will result in less clouds Friday night and slightly warmer
temperatures for Saturday. Cullen/tj


Long term...Saturday night through upper level
shortwave trough will move just north of SW Washington Saturday
night. If any marine clouds are present, this could mean more clouds
will move inland into parts of the north Willamette Valley Sunday
morning. However, troughs of similar nature recently have not been
productive at generating inland clouds, and have leaned towards a
clearer forecast with inland temperatures peaking in the upper 80s on
Sunday. Weak ridging Sunday night and Monday will result in little
change to the weather. Models hint that another low will approach
northern California from the southwest on Monday with high pressure
remaining for northwest Oregon similarly to the current weather pattern.
This may result in another round of above normal temperatures with
relatively high humidities for next week. ~Tj


Aviation...high pressure aloft and a low level northwesterly
flow pattern should produce a mix of IFR and MVFR conditions
along the coast through ~18-21z Thursday. Farther inland, expect
primarily VFR conditions through 00z Friday, but marine stratus
should push into at least the pdx Metro taf sites between
~12-18z Thursday. These cigs may reach ksle and keug during this
time as well, but confidence in timing and duration is lower at
these sites.

Kpdx and approaches...expect a period of MVFR conditions between
~12-18z Thursday. Otherwise VFR, mainly with clear skies.

&& changes. High pressure over the northeast Pacific
will continue to bring a fairly typical summertime northerly wind
pattern to the waters for much of the next week. Winds will
generally peak during the afternoon and evening hours and
generally be strongest across the waters off the central Oregon
coast versus areas farther north. Thermal low pressure over
northern California should strengthen over the weekend and
persist into next week so Small Craft Advisory level northerly
wind gusts of 25 kt should return to the waters during that time.


Pqr watches/warnings/advisories...



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