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fxus66 kpqr 271655 
afdpqr

Area forecast discussion
National Weather Service Portland or
943 am PDT Sat may 27 2017

Synopsis...an upper level ridge of high pressure will bring clouds
and cool temperatures to the coast and warmer and drier weather
inland. Thunderstorm chances develop Monday over the Cascades but
continue Tuesday and expand westward to the valley as well.
Temperatures trend gradually cooler with rain chances during the
second half of the week as a disturbance tracks across the Pacific
northwest.

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Short term...today through Tuesday...visible satellite imagery
reveals marine clouds pushed into the Coast Range gaps overnight, but
are already beginning to burn back towards the coast. Expect clouds
to retreat to near the coast with any sunshine along the immediate
coastline likely short lived as clouds should push back onto the
coast and into the Coast Range gaps fairly quickly this evening.

Water vapor satellite imagery reveals a shortwave ridge over the
northeast Pacific. The ridge axis will slowly shift inland through
Monday, which will produce little change in the overall weather
pattern except for a slow increase in cooling temperatures and marine
clouds during this time. Steeper mid level lapse rates moving into
the region will open the door to the possibility of a stray shower or
thunderstorm developing near the Cascade crest, particularly Monday
afternoon. Suspect the cap will be too much to overcome, but between
the sea breeze and slight variations in the forecast high temperature
and dewpoint forecast, feel the inherited forecast captures the
uncertainty well.

Models are coming into decent agreement that a negatively tilted
trough will push northeastward across the Pacific northwest Tuesday.
Will likely increase pops with the afternoon forecast package./Neuman




Long term...Tuesday through Friday...no changes. Previous
discussion follows. Cooler conditions as heights lower by early
Tuesday as the upper ridge shifts east of The Rockies and an upper
trough approaches the Pacific northwest. With south to southwest
flow aloft over the region, continue to include a small chance of
thunderstorms over the higher Cascade elevations, primarily near the
crest. While some differences in models with the timing of various
shortwave impulses moving through the base of the trough, overall do
see better agreement among the forecast models for the overall
pattern. Better chance for widespread showers, and perhaps even some
thunderstorms, Wednesday as the upper trough axis passes across the
region. Temperatures will trend cooler but still near or slightly
above seasonal norms by the end of the week. Cullen



&&



Aviation...IFR conditions along the coast will improve to VFR by
late morning to early afternoon. Goes16 visible loop shows
coastal stratus retreating quickly back towards beaches. VFR
conditions inland through the period. IFR conditions return to
the coast tonight.

Kpdx and approaches...VFR today and tonight. /Bentley



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Marine...winds will continue below 20 kt through at least the
middle of next week. Northerly winds continue over most of the
waters through the weekend. However nearshore winds will Switch
Back to out of the south again tonight, accompanied again by low
stratus and/or fog.

Seas have settled in the 6 to 7 foot range and will settle to
around 5 ft through most of next week. With swell period
increasing, don't even expect particularly steep or choppy seas.
Bowen



&&



Pqr watches/warnings/advisories...
or...none.
Washington...none.
Pz...Small Craft Advisory for rough Columbia River bar until 9 am
PDT this morning.

&&



$$

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