Excessive Heat in Washington, July 26 to 31, 2022

Area Forecast Discussion
National Weather Service Seattle WA
757 PM PDT Mon Jul 25 2022

.SYNOPSIS...High pressure will continue to build into the Pacific
Northwest, bringing us a stretch of hot weather inland this week.
The coast will be cooler thanks to onshore marine flow. Troughing
will be in place for the weekend for cooler temperatures and
stronger onshore flow.

&&

.UPDATE...After a warm day, quiet and pleasant conditions are
expected across the region this evening. The Heat Advisory for
portions of Snohomish, King, Pierce, and Kitsap counties was
upgraded to an Excessive Heat Warning late this afternoon due to
increased confidence in overall HeatRisk this week reaching the
High (Red) level at least Tuesday and Wednesday. It will remain
well above normal for an extended period this week, with only a
gradual ramp down by the weekend. No updates were made to the
official forecast this evening.
-Wolcott-

&&

.SHORT TERM /TONIGHT THROUGH THURSDAY/...A high pressure ridge
has encompassed much of the Pacific Northwest this evening,
providing us with the start of hot temperatures this week.
Temperatures this evening will range from mid 80s with a few low
90s possible in the south sound. The coast will be noticeably
cooler and in the 70s due to onshore flow.

Temperatures will start to climb on Tuesday (and remain hot
through Friday) as high pressure shifts further inland.
Temperatures look to steadily sit in the low to mid 90s inland
through Friday, even in the upper 90s in the hotter valleys near
the Cascade foothills. Along the coast where the flow is
primarily onshore during the overnight, expect high temperatures
in the high 70s.

The main concern are the overnight lows which are expected to be
in the mid to upper 60s inland providing little relief to those
who rely on cooler nighttime temperatures to cool down. Depending
on the strength of a onshore marine push, this may help
temperatures decrease a couple degrees - but there is uncertainty
of the extent of the marine push reaching the Seattle area.
Confidence is high for the low temperatures for the rest of the
region.

Heat Risk levels will remain elevated during the rest of the week
and can cause heat-related illnesses. Avoid working outside
during 11AM-4PM, make sure to drink plenty of water during the day
and take frequent breaks. Impacts may be greater for vulnerable
populations and those to don't have adequate cooling and
hydration.

.LONG TERM /FRIDAY THROUGH MONDAY/...Above normal temperatures
will still continue on Friday, with the warmest temperatures
being in the interior and the Cascade foothills around 90 degrees
and lows in the mid 60s. Heat Risk levels will remain elevated
during this time.

Troughing will begin to form on Saturday with stronger onshore
flow, and slightly cooler temperatures. Highs will be around mid
to high 80s, with lows creeping back to the upper 50s for the cast lower
60s inland. Expect temperatures to cool down slightly, back into
the lower 80s into Monday and for Heat Risk to lower based on
these conditions.

Mazurkiewicz

&&

.AVIATION...Northwest flow aloft with a building upper ridge across
W WA. Widespread VFR this evening and through Tuesday but there is
the potential for LIFR/IFR cigs overnight into early Tuesday along
the coast. North-northwest winds through this evening with lighter
winds into tonight. JD/18

KSEA...VFR through tonight. North-northwest winds into this evening
with lighter Northeast winds tonight. Wind speeds generally 5-10
kts.  JD/18

&&

.MARINE...North-Northwest winds into tonight. Winds will taper along
the coast tonight into Tuesday with mainly light flow. Onshore flow
increases Tuesday night for low-end SCA winds across the central and
eastern Strait of Juan de Fuca. Given how borderline winds are
forecast, will leave the issuance of any headlines to the next
shift. Potential for additional SCA winds in the Strait of Juan de
Fuca each evening through the week. Seas 3 to 5 feet through
Thursday. JD/18

&&

.HYDROLOGY...The daily hydrology discussion has ended until the
start of the next rainy season; it will only be updated as needed
until then.

&&

.SEW WATCHES/WARNINGS/ADVISORIES...
WA...Excessive Heat Warning from noon Tuesday to 4 PM PDT Friday for
     Bellevue and Vicinity-Bremerton and Vicinity-East Puget
     Sound Lowlands-Everett and Vicinity-Seattle and Vicinity-
     Tacoma Area.

     Heat Advisory from noon Tuesday to 4 PM PDT Friday for Hood
     Canal Area-Lower Chehalis Valley Area-Southwest Interior-
     West Slopes North Cascades and Passes-West Slopes North
     Central Cascades and Passes-West Slopes South Central
     Cascades and Passes-Western Skagit County-Western Whatcom
     County.

PZ...None.
&&

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