Heat in Washington, March 15 to 16, 2024

Area Forecast Discussion
National Weather Service Seattle WA
935 AM PDT Fri Mar 15 2024

.UPDATE...No changes made to the inherited forecast. The previous
discussion remains below.

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.SYNOPSIS...High pressure is building across the Pacific
Northwest bringing a period of warmer and drier conditions
through early next week. Here we will see the warmest
temperatures of the year so far. Then, cooler and wetter weather
looks to return around the middle of next week.

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.SHORT TERM /TODAY THROUGH SUNDAY/...Upper level ridging continues
to build just offshore of western Washington, continuing the trend
of high cirrus drifting over the area. These high clouds, as well
as light surface winds keeping up tonight, should mitigate
widespread fog development this morning. Fog probabilities are
fairly low, but highest over Olympia and into the Chehalis valley.
Lows this morning will likely again be dictated by the dew point
temperatures, which are sitting in the low to mid 30s.

High temperatures will continue their increasing trend today,
reaching into the low to mid 60s across the region with decreasing
cloud coverage. A weak surface thermal trough along the coast
will help this warmup as winds turn easterly/offshore and
downslope. Winds may be breezy through the gaps in the Cascades
but look to remain below advisory threshold. Low temperatures in
the low to mid 40s. Again chances exist for light shallow fog,
particularly in the most vulnerable river valleys.

This weekend (and into Monday) looks to be the warmest days as
the upper level ridge moves westward over the region, centered
over southern British Columbia. This will result in highs in the
upper 60s to low 70s, especially through the Southwest interior
and the western foothills of the Olympics and Cascades. These
highs will be flirting with record temperatures across the region. Lows
will be in the mid 40s. Afternoon relative humidities look to
bottom out between 40-50%. Overall, a very pleasant weekend for
western Washington.

.LONG TERM /MONDAY THROUGH THURSDAY/...The pattern continues into
Monday and into Tuesday as the upper level ridge begins to drift
southward into the Great Basin region. The ridge should continue
to  move southward and deamplify enough by Wednesday to trend
temperatures closer to normal. This will also allow for shortwaves
to track into the region, with ensembles hinting at chances for
light precipitation returning to the forecast on Wednesday. Any
specifics on the pattern or specific PoPs are unclear at this
point, with cluster analysis still showing somewhat divergent
solutions beginning Wednesday.

LH

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.AVIATION...Upper level ridge centered offshore with north
northeasterly flow aloft into Saturday. In the lower levels
offshore flow increasing today with the low level offshore flow
pattern continuing into Saturday.

Just some high clouds moving through the area into Saturday.
Patchy fog reducing visibility to 3-5sm over the Southwest
Interior 13z-16z.

KSEA...Just some high clouds into Saturday. Northerly winds 8 to
12 knots easing tonight.

Felton

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.MARINE...High pressure centered over Southern British
Columbia combined with a thermally induced trough expanding
northward along the coast will give the area increasing offshore
flow today. The offshore flow pattern will remain intact through
Sunday. Trough shifting east of the Cascades Sunday with onshore
flow for the first part of next week.

Easterly winds near 20 knots at the West Entrance to the Strait of
Juan de Fuca and near gaps in the coastal terrain this afternoon
into Saturday.

Felton

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.HYDROLOGY...No river flooding expected in the next 7 days.

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.SEW WATCHES/WARNINGS/ADVISORIES...
WA...None.
PZ...None.
&&