FXUS66 KPQR 262206

AFDPQR



Area Forecast Discussion

National Weather Service Portland OR

306 PM PDT Thu Jun 26 2025



.SYNOPSIS...After one more day sitting in an onshore flow

pattern with patchy drizzle (mainly near the coast) and near to

slight below normal temperatures, a rapid warming trend takes 

hold over the weekend into early next week. Confidence is high 

inland temperatures approach or exceeding 90 degrees in many 

locations on both Sunday and Monday. We're also keeping an eye 

on the growing possibility (20-40%) for Cascade thunderstorms 

early next week as well. At least high temperatures trend 

cooler (low to mid 80s) by the middle of next week.



&&



.SHORT TERM...Now through Saturday Night...Current radar and

satellite imagery depicts increasing cloud cover and shower 

activity near the coast in response to a weak upper-level 

shortwave trough beginning to move inland. This features likely 

increase light shower activity across the north Oregon 

Coast/Coast range through the Washington Coast and Willapa Hills

into the early evening hours while maintaining broad onshore 

flow through tonight. Can't rule out a light shower

Longview/Kelso northward or in the south Washington Cascade

foothills too, but the bulk of the activity inland should stay 

to our north.



Overall guidance shows little day to day change in conditions for

Friday albeit with any lingering light rain showers/drizzle 

holding more confined to southwest Washington excluding the

lowlands south of Longview/kelso. Cloud cover has the potential

to scatter out a bit more during the afternoon hours, 

especially in the central and southern Willamette Valley, 

allowing high temperatures to increase a few degrees into the 

mid 70s where this clearing takes place. Through Friday onshore 

flow will also maintain breezy west winds through the central 

Columbia River Gorge each afternoon as winds gust to 25-35 mph 

in some spots around Hood River. 



Come Saturday upper-level heights begin to rise across the

area as a ridge of high pressure slowly starts to amplify over

the Pacific Northwest favoring dry conditions. At the same time,

both deterministic and ensemble models depict a cutoff low 

developing over the California coast - this will come into play

regarding T-storms chances early next week (see Long Term 

discussion). The persistent morning cloud cover which has kept 

a damper on temperatures the last couple of days will be less 

prevalent thanks in-part to a developing offshore component in 

winds just above the surface. As a response, high temperatures 

jump into the upper 70s to low 80s across the inland valleys - 

roughly 2 to 5 degrees above normal for late June. Expect 

temperatures to keep climbing the second half of the weekend 

too. -Schuldt



.LONG TERM...Sunday through Wednesday... Warmer weather finally

takes hold on Sunday with offshore flow in place across the

region at 850mb and a near surface thermal trough overhead as

well. Temperatures still look to peak during this early next

week period (Sunday and Monday) as the ridge continues to 

amplify, with the NBM now depicting a 40-70% chance to meet or

exceed 90 degrees in the Willamette Valley on Sunday followed 

by a 75-90% chance on Monday. Probs to reach 95 degrees continue

to sit closer to 15-35% in most locations in the Willamette 

Valley, representing more of a reasonable worst case scenario 

for heat on Monday. Temperatures look to slowly decrease 

somewhat beyond Monday, but will still remain well above normal 

as guidance keeps highs in the 80s for much of the rest of the 

week, showing around a 30-45% to reach as high as 90 degrees for

Tuesday through Thursday - higher model uncertainty resolving 

the upper-level pattern by the middle of next week. 



The other forecast concern in the long term will be the 

potential for thunderstorms along the Cascades during the first 

half of next week (highest relative threat on Monday) which 

will largely be dependent upon the evolution of the 

aforementioned cutoff low near the California coast. This will 

have the potential to draw monsoonal mid level moisture 

northward into our area in southeast flow aloft, which is often 

challenging for the NBM to resolve. A farther north position of 

the low will generally be more favorable for thunderstorms to 

reach into the northern Oregon Cascades and south Washington

Cascades. Confidence is decent (50-60%) for activity in at 

least the eastern Lane County Cascades southward. One 

interesting facet worth highlighting is most current model 

solutions shows a slight easterly component to the southerly 

flow between 700-500mb which would promote a longer residence 

time for activity over the Cascades should it develop. For now, 

will maintain a 15-24% chance of thunderstorms along parts of 

the Cascades both Monday and Tuesday afternoon, but will need to

keep a very close eye on how this pattern evolves in the coming

days. -Schuldt/CB





&&



.AVIATION...Onshore flow and marine stratus over the next 24

hours. Coastal terminals will generally be MVFR but some areas,

like KONP, will experience IFR conditions. There is a 30% chance

of IFR CIGs along the coast. Satellite shows low-end VFR CIGs with

multi-layer cloud deck inland. Overnight, the lower level clouds

will become more dense. Near the Cascades, east of KSLE, will see

a 40-50% chance of MVFR CIGs. Trended towards a "high-end" MVFR

deck, though it is nearly as probable that VFR conditions will

prevail. 



Westerly winds within the Columbia River Gorge will amplify not

only this afternoon, but also after 20Z Friday. This will mainly

impact terminals like K4S2. 



PDX AND APPROACHES...Mixture of MVFR and VFR conditions with a 75%

chance of VFR CIGs through the next several hours. MVFR stratus

will reform overnight just to the east of the airport and 

therefore, cannot rule out back building of the stratus onto the

runways and impacting easterly approaches. Breaking out of clouds

will occur once again after 18Z Friday. 				-Muessle



&&



.MARINE...Weak perturbations will move through the onshore flow

through the Saturday before high pressure begins to build on

Sunday. Westerly winds of 5-10 kt with gusts up to 20 kt expected

through Friday, before sifting to the north at 15-20 kt with 

gusts up to 25 kt Saturday night. The waters south of Tillamook 

have a 70% chance of gusts up to 30 kt, and elsewhere around a 40%

chance. Ultimately, gusts will be dependent on the strength of a

ridge and thermal trough that are beginning to develop Sunday. 

Seas during this time will remain generally unchanged at 5-7 ft at

9 seconds except where wind waves are higher. 



Moving into Sunday and Monday, weather will become more dynamic as

temperatures rise considerably, and a low moves over northern

California. This pattern is consistent with increasing

thunderstorm chances. While this will mostly impact areas inland,

cannot rule out a strike or two on Monday evening. 		-Muessle



&&



.PQR WATCHES/WARNINGS/ADVISORIES...

OR...None.

WA...None.

PZ...None.

&&



$$



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