598
FXUS66 KPQR 260947
AFDPQR

Area Forecast Discussion
National Weather Service Portland OR
247 AM PDT Sun May 26 2024

.SYNOPSIS...Warmer and drier with more sunshine across much of
the area today, with the exception of clouds and maybe a few
passing showers across parts of southwest Washington.
Temperatures peak on Monday with highs in the 70s in many
locations. Cooler and wetter weather returns from Tuesday
through the middle of next week.

&&

.SHORT TERM...Now through Monday Night...Satellite imagery shows
mostly clear skies across much the area early this morning as
transient shortwave riding crosses overhead, with any lingering
cloud cover confined mainly to northern coastal areas and parts
of the Cascades. Today will be characterized by benign onshore
flow yielding mostly dry conditions as temperatures warm to
around 70 degrees in most locations away from the coast. The
exception will be over the far northern coastal areas and parts
of the Cowlitz River Valley, where cloudier skies will prevail
and a few showers can`t be ruled out through this afternoon as
a weak disturbance crosses the Washington Coast. Models then
remain in excellent agreement on warmer temperatures for Monday
as an upper level ridge builds east of the Cascades, allowing
highs to push well into the 70s throughout the interior valleys.
Guidance has converged on temperatures in the mid to upper 70s
around the Portland Metro, with around a 20 percent chance that
highs could reach 80 degrees in a few spots. The shift back
towards a cooler pattern begins Monday night as the next trough
approaches from the Pacific, bringing a chance of rain back to
the coastal areas after midnight. /CB

.LONG TERM...Tuesday through Saturday...Cooler and wetter
weather returns to the region on Tuesday as guidance has
continued to incrementally shift the downstream ridge farther
east in recent runs, allowing the next trough from the Gulf of
Alaska to move over the Pacific Northwest by Tuesday afternoon.
This will bring widespread light rain the region Tuesday into
Wednesday, with temperatures falling back into the low to mid
60s and snow levels lowering across the Cascades but likely
remaining just above the passes. QPF amounts look rather minimal
through mid week, with the bulk of guidance depicting no more
than one to two tenths of an inch in the lowlands and closer to
a quarter to a half inch in the higher terrain through
Wednesday. Light shower activity looks to linger into Thursday
as northwest flow develops on the back side of the departing
trough. WPC ensemble clusters have begun to favor a return to
ridgier pattern late in the week, which is reflected by forecast
highs climbing back into the 70s from Friday into next weekend.
/CB

&&

.AVIATION...Onshore flow weakening and clouds clearing out as
high pressure builds into the region this morning. With areas
clearing, this may be enough for patchy low stratus or fog due to
radiational cooling. While NBM does not suggest low stratus or
fog, HREF guidance shows about 20-30% chance for MVFR or lower
CIGS between KUAO to KEUG from 11Z to 16Z Sunday. Current
observations (09Z Sunday) suggest no fog or low stratus formation
will occur this morning, but will continue to monitor. Otherwise,
expect showers and high end MVFR conditions along the NW Oregon
coast and SW Washington coast as a low pressure system located in
the Gulf of Alaska continues to push southeast.

PDX AND APPROACHES...Expect VFR conditions through the period.
CIGS around 8000-9000 ft scattering out this morning. Variable
winds becoming northwesterly in the afternoon but will remain
light. -JH

&&

.MARINE...Brief showers expected in the northern waters this
afternoon as a low pressure system in the Gulf of Alaska tries to
push southeastward. This system will notably move into our region
late Monday night into Tuesday. Very little impacts are expected
as the system is not overly deep and is generally staying more
north. Otherwise, will still see generally onshore flow through
the forecast period. Will see increased winds late into the week.
-JH

&&

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

$$

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