558
FXUS66 KPQR 061659
AFDPQR

Area Forecast Discussion
National Weather Service Portland OR
959 AM PDT Fri Jun 6 2025

.SYNOPSIS...
A continued warming trend is expected through
Sunday as ridging aloft remains the dominant feature locally.
The hottest days of the year so far are expected as inland
valley areas are likely to surpass 90 degrees both Sunday and
Monday, while the coast stays cooler. A breakdown of the ridge
and may see a return to more seasonable temperatures later next
week.

&&

.SHORT TERM...Now through Monday Night...Upper-level ridging
continues to build over the Northeast Pacific, while a
positively-tilted trough extending from the Northern Rockies to
central California will be pinched off beneath the ridge,
yielding a Rex blocking pattern which will slowly drift to the
east through early next week. Mid-level temperatures will
steadily warm from 13-15C at 850 hPa today to 18-20C as the
ridge axis passes overhead on Sunday, some 2-3 standard
deviation above normal, while deeper mixing realizes
successively warmer temperatures each day at the surface. Expect
afternoon highs to warm from the low to mid 80s today across
inland valleys to low to mid 90s on Sunday. Chances for highs of
95F or higher will be at least 25-50% along the I-5 corridor
Saturday, while Salem northward through Clark County, Washington
see the highest chances, some 60-85%. Guidance has come into
better agreement that hot temperatures will continue into Monday
as the ridge begins to shift inland and deamplify, but another
day in the 90s is favored with similar temperatures to Sunday.
Along the coast, sufficient onshore flow will see much cooler
albeit still unseasonably warm conditions in the 60s to mid 70s
through Monday. Overnight lows will similarly trend warmer,
reaching the low 60s across the northern and central Willamette
Valley and Columbia Valley from Hood River through
Kelso/Longview, with 50s elsewhere, providing some relief from
the daytime heat.

Temperatures this warm this early in the season will support a
Moderate HeatRisk across more densely populated portions of the
inland valleys on Saturday, namely along the Willamette and
Lower Columbia Valleys from Salem north through Kelso/Longview
including Portland as well as the Lower Hood River Valley, while
Moderate HeatRisk is more widespread as temperatures reach
their peak on Sunday, excepting only the High Cascades and
coastal areas. Areas along the Columbia Gorge may see a Major
HeatRisk on Sunday as temperatures reach the mid to upper 90s.
Daily record high temperatures could be challenged Sunday and
Monday at inland climate sites, including Portland, Salem, and
Eugene. While not extreme, the prolonged early-season heat may
still pose health risks to sensitive populations, those who work
outdoors, or those who do not have access to air conditioning.
-Picard


.LONG TERM...Tuesday through Friday...By Tuesday into the
middle of next week, the ridge will break down as large-scale
troughing becomes favored over the West Coast. While the details
remain low-confidence, a return to more seasonable temperatures
in the 60s and 70s is favored by the latter half of the week.
Embedded shortwaves passing over the Pacific Northwest may bring
some low chances for precipitation, but at this lead time, only
a few global ensemble members are suggesting any accumulating
rainfall. -Picard


&&

.AVIATION...Minimal impacts to the aviation forecast as high
pressure lingers over the region. This ridge will keep CIGs
generally VFR except along the coast where satellite shows the
clouds quickly eroding. High probability (Greater than 85%
chance) in VFR CIGs around KONP by 18Z Friday. Diurnally driven
northerly winds will increase in the afternoon through the
Willamette Valley.

PDX AND APPROACHES...VFR with no concerns through the forecast
period. Diurnal northwesterly winds with periodic gusts up to 20
kt (30% chance between 00Z-6Z Saturday). However, they will not be
consistent. Winds ease overnight and VFR clouds fill in.
-Muessle


&&

.MARINE...
Minimal changes to the forecast. High pressure
offshore will maintain breezy northerly winds across the waters
through early next week. A Small Craft Advisory remains in
effect for most coastal waters except the inner waters north of
Cape Falcon and Columbia River Bar. Within the Advisory, expect
northerly winds of 15-20 kt with gusts to 25-30 kt. The
strongest gusts are expected in the outer waters south of Cape
Falcon, where pressure gradients are tighter. Seas remain
dominated by northerly wind waves and northwesterly swell
through the weekend, with significant wave heights of 5 to 8 ft
at 8 to 10 seconds. Expect steep and choppy seas when winds are
strongest. -Alviz

&&

.CLIMATE...
Daily record high temperatures (for reference):

Sunday, June 8

Portland94 (1955)
Salem98 (1955)
Eugene93 (2015)
Astoria97 (1903)

Monday, June 9

Portland95 (1955)
Salem96 (1955)
Eugene91 (2015)
Astoria87 (1924)

&&

.PQR WATCHES/WARNINGS/ADVISORIES...
OR...None.
WA...None.
PZ...Small Craft Advisory until 11 PM PDT this evening for PZZ252-
     253-271>273.
&&

$$

www.weather.gov/portland

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