FXUS66 KPQR 091724 AAB
AFDPQR

Area Forecast Discussion...UPDATE
National Weather Service Portland OR
1023 AM PDT Thu Jul 9 2026

Updated Aviation and Marine discussions

.SYNOPSIS...Persistent onshore flow will continue to yield dry 
and seasonable weather through this weekend. Daytime highs trend
warmer early next week as high pressure builds over the Great 
Basin. After the middle of next week, uncertainty increases in 
the exact forecast, but a warming and drying trend is expected.

&&

.DISCUSSION...Today through Wednesday...Minimal changes in the
overall synoptic pattern through the remainder of the week. A
broad, upper level trough will continue to push south and east
through British Columbia, while a broad area of high pressure
remains anchored over the Great Basin. This synoptic set-up is
resulting in zonal flow aloft and onshore flow at the surface. 
This pattern will help to maintain near normal daytime highs 
across the forecast area as well as slightly cooler than normal,
overnight lows. 

As the start of next week approaches, another upper level 
trough or closed low, looks to dive southward out of the Gulf of
Alaska and move into British Columbia. Which will result in the
upper level flow pattern becoming southwesterly. In addition to
the Alaskan system, the Great Basin high will also re-build. 
This general pattern change will result in a slight warming 
trend starting Sunday and continuing through the middle of the 
week. Expect high temperatures through the first half of next 
week to reach the mid to upper 80s inland and mid 60s to near 70
degrees along the coast, while overnight lows similarly push a 
few degrees warmer into the mid 50s across the region. This 
combination of temperatures continues to support widespread 
Minor HeatRisk across the majority of the region with isolated 
areas of Moderate HeatRisk in the Portland/Vancouver metro and 
through the Columbia Gorge, especially on Tuesday.

There remains a broad region from Salem north through the Lower
Cowlitz Valley and east along the I-84 corridor through the 
Gorge where there is a 20-50% chance of Moderate HeatRisk on 
both Monday and Tuesday if forecast temperatures trend warmer, 
with the highest likelihood in the Lower Tualatin Valley (Beaverton,
Tigard, Tualatin) and neighboring portions of Multnomah and 
Clackamas Counties (Portland, Wilsonville). Chances for Major 
HeatRisk are 10% or less across the region. Uncertainty in the 
temperature forecast increases beyond Wednesday as consensus is
relatively low in the long-term evolution of the strong upper 
ridge. Nonetheless, chances for rain remain minimal through the 
period. /42-36

&&

.AVIATION...Zonal flow aloft gradually turning southwest tonight
ahead of an approaching upper level trough. Predominately VFR
conditions are expected for inland terminals through at least 12z
Friday, while VFR is likely at the coast until 02-04z Friday. Some
lingering stratus near KAST is expected to scatter out by 19z. 
Marine stratus will likely push back on shore this evening with 
probs for lower- end MVFR CIGs increasing to around 80-90% after 
06z Fri, while chances for IFR conditions are lower at around 
20-30%. As the upper trough approaches expect the marine layer to 
deepen with increasing chances for stratus to push farther inland,
though chances for MVFR reaching the Portland metro remain capped
at around 20-40% between 12-18z Friday. North to northwest winds 
increase again this afternoon with gusts up to 25 kt at coastal 
terminals.

KPDX AND APPROACHES...VFR under mostly clear skies expected
through at least 12z Friday. A marine push may return stratus to
the area early Friday morning with around a 20-40% chance of MVFR
CIGs between 12-18z Fri. Northwest winds expected to increase to
around 8-10 kt this afternoon. /DH

&&

.MARINE...High pressure over the waters today will maintain breezy 
north to northwest winds through this evening. Gusts up to 20 kt
will be possible south of Cape Foulweather. A weak cold front will
move across the waters on Friday, ultimately disrupting the high
pressure and decreasing winds across the waters. High pressure
effetely rebuilds over the coastal waters through the weekend, 
returning northerly winds later Saturday and increasing pressure 
gradients on Sunday, returning chances for gusts up to 25 kt. Seas
are expected to remain around 4 to 6 ft as relatively benign 
conditions persist through the weekend and into the start of next 
week. /DH

&&

.PQR WATCHES/WARNINGS/ADVISORIES...

OR...None.
WA...None.
PZ...None.
&&

$$

www.weather.gov/portland

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