Big Mosquito Lake Washington Weather Forecast Discussion

607
FXUS66 KPQR 120441 AAB
AFDPQR
Area Forecast Discussion...UPDATED
National Weather Service Portland OR
940 PM PDT Sat Oct 11 2025
Updated aviation and short term discussions. Updated
PQR/WATCHES/WARNINGS/ADVISORIES.
.SYNOPSIS...A series of broad upper-level troughs will
continue to drive cool and unsettled weather across the Pacific
Northwest through Monday. Expect periodic rain, mountain snow,
and below-normal temperatures. Conditions gradually moderate
midweek as a ridge builds over the region, though model
uncertainty grows toward late week.
&&
.SHORT TERM UPDATE...Saturday night, Sunday night and Monday
night...Confidence has increased for a transition from mostly cloudy
skies and wet weather to clearing skies and dry weather over the
Upper Hood River Valley beginning Monday night. Excess cloud cover
should be enough to keep low temperatures above freezing for Hood
River, Odell and Parkdale both Saturday night and Sunday night.
However, clearing skies and calm winds Monday night will allow for
excellent radiational cooling, with lows most likely bottoming out
somewhere between 28-32 degrees from Odell to Parkdale. Probabilities
for temperatures at or below 32 degrees range between 50-90%.
Probabilities for temperatures of 28 degrees or colder range between
5-35%. These probabilities are highest in the Parkdale area and
lowest in Odell. Given the increase in confidence, have decided to
issue a Freeze Watch from 12 AM to 9 AM Tuesday for the Upper Hood
River Valley. Sub-freezing temperatures could kill crops, other
sensitive vegetation and possibly damage unprotected outdoor
plumbing. -23
&&
.DISCUSSION...Tonight through Friday...Current IR and Water
Vapor satellite imagery shows a broad, upper level low east of
the Cascades this afternoon. Radar also shows light showers
slowly moving eastward across the CWA. As this low continues to
shift eastward, a second trough can also be seen drifting down
from Western Canada and this low will keep widespread rain in
the forecast through the remainder of the weekend and into the
start of the upcoming week. Cold air from the first low,
combined with the precipitation from the second low will also
result in accumulating snow along the Cascades through Monday
morning. Therefore, have issued a Winter Weather Advisory for
elevations above 4000 ft as there is an 80% chance of total
snow accumulations of 2 to 6 inches of wet snow for areas near
Santiam, Bennett and Willamette Passes. Highway 26 near
Government Camp has an 80% chance of a trace to 3 inches of wet
snow. For elevations above 5000 ft, there is an 80% chance that
snow accumulations will end up between of 4 to 15 inches.
Overall, there is a 50% chance of at least 12 inches of snow,
primarily for locations north of The Three Sisters and this
scenario could result in vehicles becoming stranded along
unmaintained roads. Sunday, we continue to transition to more
showery/convective pattern and that is resulting in a 15% chance
for thunderstorms through much of Sunday, primarily along the
coast but still possible inland.
Colder air aloft, will also bring about cooler daytime and
overnight temperatures. Sunday and Monday expect daytime highs
in the mid 50s to low 60s for inland and coastal locations.
Colder air aloft, is also bringing about a slight increase in
instability. The Cascades will have daytime highs in the upper
30s to upper 40s. Sunday night into Monday could see at or
near-freezing overnight lows for the Cascade Foothills eastward.
This includes the Hood River. Monday night into Tuesday will
also have at or near- freezing overnight lows. Either of these
two nights could result in a Freeze Watch or Warning being issued,
but given the high uncertainty for overnight cloud cover, will hold
off on any hazards at this time.
Tuesday into Wednesday, a models have a broad, upper level ridge
developing which will result in a warming and drying trend. Daytime
highs will warm into mid 50s to upper 60s. Towards the end of
the upcoming week, uncertainty increases as several ensemble
members rebuild an offshore low and push it back toward the
coast. If this scenario develops, another round of cool and
moist conditions would bring increasing cloud cover as well as
another round of precipitation. However, confidence in this
late week pattern remains low. /42
&&
.AVIATION...An upper level low pressure system will continue to
produce periods of showers through 06z Monday, with showers
becoming more frequent again after 12-15z Sunday. A mix of VFR
and MVFR conditions will continue along the coast through 00z
Monday. Inland TAF sites can expect an extended period of VFR
conditions tonight before the next round of showers arrive by
12-15z Sunday, resulting in a 30-50% chance for MVFR ceilings
at any given hour between 15z Sunday and 06z Monday. Cigs will be
lowest with passing showers.
KPDX AND APPROACHES...An upper level low pressure system will
continue to produce periods of showers and predominantly VFR
conditions tonight. The next round of showers arrives around
12-15z Sunday. The probability for MVFR ceilings climbs to 30-45%
between 15z Sunday and 06z Monday, with the lowest cigs expected
to occur with passing showers. -23
&&
.MARINE...A weak low pressure system shifting inland will result
in northwesterly winds building across the waters this afternoon.
There is a 25% chance that gusts briefly peak around 35 kt beyond
40 NM across the northern waters, but given the brevity and low
confidence of occurrence will keep Small Craft Advisory in place.
There is an 80% chance that seas build into the 9-14 ft range
across the waters this evening into early Sunday. The highest seas
will be across the northern outer waters while the lowest seas
will be across the southern inner waters off the central coast of
Oregon.
A weak low pressure will then drop southward across the waters
late Sunday into early Monday. This will usher in a reinforcing
shot of gusty north to northeasterly winds during this period.
Seas will remain elevated as a result. High pressure then looks to
build back across the northeastern Pacific during the middle of
next week. This looks to allow seas to drop down to around 5 ft.
There remains quite a bit of uncertainty surrounding the weather
pattern next week. There is an 80% chance that significant wave
heights will climb and end up somewhere between 6 and 13 ft by
next Friday or Saturday.
&&
.PQR WATCHES/WARNINGS/ADVISORIES...
OR...Freeze Watch from late Monday night through Tuesday morning for
     ORZ121.
Winter Weather Advisory from 8 AM Sunday to 11 AM PDT Monday
     for ORZ126>128.
WA...Winter Weather Advisory from 8 AM Sunday to 11 AM PDT Monday
     for WAZ211.
PZ...Small Craft Advisory until 9 PM PDT Sunday for PZZ210-251>253-
     272-273.
Hazardous Seas Warning until 5 PM PDT Sunday for PZZ271.
&&
$$
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NWS PQR Office Area Forecast Discussion