879
FXUS66 KPQR 192206
AFDPQR

Area Forecast Discussion
National Weather Service Portland OR
306 PM PDT Wed Jun 19 2024

.SYNOPSIS...Much warmer through the remainder of the week under
building high pressure, with moderate heat risk expected from
Portland to Salem Thursday through Saturday. More seasonable
temperatures return Sunday into early next week.

&&

.DISCUSSION...Today, clear skies across northwest Oregon and
southwest Washington as northerly flow continues to advect
drier air into the region. Expect above normal temperatures to
last through the end of the week as high pressure builds and a
surface thermal trough continues to strengthen from the
California Central Valley into south-central Oregon. This will
induce easterly flow over the Cascades and downsloping into the
interior lowlands, increasing highs well into the 80s this
afternoon.

Heat looks to peak Thursday into Friday as 500 mb heights
continue to gradually rise and 850 mb temps increase to around
15-17 C. NBM and ensemble guidance continue to depict
temperatures ending up right around 90 degrees both Thursday and
Friday afternoon from the Portland metro down to Salem. As for
the south Willamette Valley and the I-5 corridor in southwest
Washington, highs will be around the mid to upper 80s Thursday
and Friday. The chance to reach 95 degrees on Friday is around
20-40% in the Portland and Salem areas, with chances around 5
percent in the Eugene area. These probabilities improve
confidence in the temperature forecast for the end of the week
as highs around 90 support a moderate HeatRisk for the Portland
and Eugene areas. Overnight lows will drop into the mid to
upper 50s, offering enough overnight recovery to help mitigate
more widespread or cumulative HeatRisk concerns.

Into the weekend, temperatures may remain a bit warmer on
Saturday as models suggest a delay in strong onshore flow as
high pressure shifts east of the region. This is reflected by
NBM probabilities (40%) of reaching 90 degrees on Saturday for
the Portland and Salem areas. More pronounced cooling will still
arrive by Sunday as WPC ensemble clusters continue to depict
the next trough approaching the Pacific Northwest, dropping
temperatures back near seasonal normals in the mid 70s. These
temperatures will persist through the early part of next week
as the region remains under the influence of the trough. Models
have started to trend drier with the forecast as the core of the
upper low remains well to the north over British Columbia, with
any low end precipitation chances towards the end of the period
now generally confined to the far north Oregon Coast and
southwest Washington. -JH/CB

&&

.AVIATION...Broad upper level troughing persists over the region
with northwest flow aloft. Surface high pressure will maintain VFR
conditions across much of the region. MVFR/IFR clouds are possible
along the coast tonight and could impact KONP for a brief period,
similar to last night. N/NW winds around 5-10 kt will continue
inland and slightly higher along the coast, up to 15 kt.

PDX AND APPROACHES...VFR under mostly clear skies. N/NW winds
at 5-10 kts expected. -Batz

&&

.MARINE...Not much change as high pressure offshore is expected
to persist through the week. Northerly winds around 15-20 kt will
continue today. Expect periods of winds gusting up to 25 kt through
Friday during the late afternoon and evenings. Gusty winds will
relax after 11 PM for a brief period but will increase back up to 25
kt for the outer waters. The inner waters may see a few gusts around
20 kt but not expecting widespread so the Small Craft has not been
extending for the inner waters. Seas around 4 to 6 feet will
generally be wind driven through the week. A weak front is expected
to approach the waters this weekend. -Batz/DH

&&

.PQR WATCHES/WARNINGS/ADVISORIES...

OR...None.
WA...None.
PZ...Small Craft Advisory until 11 PM PDT this evening for PZZ251>253.

     Small Craft Advisory until 8 PM PDT Thursday for PZZ271>273.
&&

$$

www.weather.gov/portland

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