Molalla, Oregon Weather Forecast Discussion

061
FXUS66 KPQR 291143 AAA
AFDPQR
Area Forecast Discussion...UPDATED
National Weather Service Portland OR
443 AM PDT Mon Sep 29 2025
Updated Watches, Warnings and Advisories
.SYNOPSIS...Active weather will result in wet and cool
conditions for the work week. Multiple frontal systems will
bring periods of widespread rain and breezy winds to the region.
The first will be Monday, followed by the strongest system
Tuesday through Wednesday, with unsettled conditions continuing
through Friday.
&&
.DISCUSSION...Today through Saturday...Satellite imagery this
morning has a broad low pressure centered near 55N/142.45W.
This low will send multiple frontal systems into the PacNW. The
first front this morning will bring increased cloud cover,
southerly winds and widespread rain to the region. Expect
southerly winds along the coast with gusts up to 35 mph through
Monday afternoon. Widespread rain is already being observed
along the coast this morning and will be slowly moving inland
into the valley by mid to late morning. Model guidance continues
to indicate this front will weaken as it makes landfall, and
rain is mostly expected to dissipate by late afternoon/early
evening before becoming more showery in nature. Latest guidance
indicates up to 0.25"-0.50" of rain expected along the coast and
Coast Range with 0.10"-0.33" inland and 0.20"-0.50" for the
Cascades through 5 AM Tuesday.
The second front will not be far behind even with a very brief
break late Monday night into Tuesday morning. This second front
looks to be stronger and will bring much heavier precipitation
to the region by late Tuesday morning/Tuesday afternoon.
Southerly winds expected to be stronger with gusts up to 45 mph
along the coast, though there could be a few isolated gusts up
to 50 mph. Inland areas will mainly see gusts up to 25 mph.
However, guidance is showing that there is a 25-50% probability
of peak gusts up to 30 mph Tuesday. Rain will be more
widespread with this system. Current HREF onset timing has
precipitation starting around 5AM-8AM along the coast and
12PM-2PM for inland locations. Conditions become more showery by
Tuesday afternoon and will result in increasing chances
(10-20%) of thunderstorms for the coast through Tuesday
afternoon through the evening. Not expecting severe
thunderstorms, but any that form could produce heavy rain, gusty
winds, and frequent lightning. Guidance indicates up to
0.40"-1.00" of rain expected along the coast and Coast Range
with 0.20"-0.40" inland and 0.30"-0.70" for the Cascades through
Wednesday morning.
Wednesday into Thursday, the third frontal system will swing
across the region. Some uncertainty remains on the timing and
strength of the next frontal system. Winds are expected to
remain generally elevated Wednesday through Thursday with gusts
up to 35 mph along the coast and 25 mph inland, possibly
increasing again briefly as the front passes. Thunderstorm
chances return and will be more widespread across the CWA from
Wednesday through Thursday evening. Again, not expecting severe
thunderstorms, but any that form could produce heavy rain,
gusty winds, and frequent lightning. Guidance indicates an
additional rain totals up to 0.30"-1.00" of rain expected along
the coast and Coast Range with 0.15"-0.40" inland and
0.15"-0.70" for the Cascades for Wednesday into Thursday.
Depending on the timing and track of this last system, showers
could continue into Friday and Saturday, though a number of
ensemble members show dry conditions for the latter part of the
week and into the weekend. Ensembles indicate a longwave trough
will begin deepening somewhere over the Western US on Saturday,
but the WPC 500 mb cluster analysis indicates a nearly 50/50
chance of it deepening over the Great Basin area vs over the Pac
NW. If it deepens over the PacNW, rain chances will be higher.
If it deepens over the Great Basin, dry weather will prevail.
/42-HEC
&&
.AVIATION...VFR conditions with high clouds persist across the
Willamette Valley ahead of the next system. High-end MVFR/low-end
VFR conditions along the coast as a frontal system moves in.
Rain should begin along the coast over the next few hours and
reach the Willamette Valley by 15Z-18Z Monday. Winds generally
out of the south ahead of the front, with gusts up to 25 kt likely
at coastal terminals through the TAF period. Inland, winds remain
under 10 kt and generally out of the south. Once the front moves
inland, flight conditions within the Valley will fall towards
low-end VFR (less than FL040) with a 20-40% chance for MVFR
conditions. Widespread rain transitions into post-frontal showers
behind the front around 18Z Mon along the coast and 18Z-20Z Mon
for inland locations. The front is expected to be out of the
airspace around 00Z-03Z Tues with flight conditions expected to
improve to VFR.
KPDX AND APPROACHES...VFR with high clouds, dropping to low-end
VFR around 18Z Mon as a front moves through and brings widespread
rain. 10-25% chance for MVFR conditions from 18Z Mon-00Z Tue.
Southeasterly winds around 6-10 kt. /42
&&
.MARINE...A cold front moving across the waters through early
this morning will continue to produce southerly winds of 15-25
kt with gusts up to 30 kt. Seas of 8-11 ft will persist as well.
Therefore will maintain the current Small Craft Advisory for
all waters. After the front moves onshore Monday morning, winds
will ease to 10-15 kt while seas subside to 7-9 ft by late Monday
afternoon.
Another, more potent frontal boundary will approach the waters
tonight and push onshore through Tuesday night. Southerly winds
will increase as the front approaches the coast and moves inland.
This will result in southerly winds of 25 to 35 kt with gusts up
to 45 kt. These strong winds will also result in seas building to
15-18 ft by Tuesday afternoon, with a 5-25% chance of 20 ft seas
beyond 30 NM. These elevated winds and seas are expected to
persist through at least Thursday night. Therefore, have upgraded
the Gale Watch to a Gale Warning. As the front moves further
inland by early Wednesday, winds and seas will remain elevated.
These conditions will warrant a Small Craft Advisory or more
likely a Hazardous Seas Warning to be issued.
Southerly winds steadily weaken below 15 kt by Thursday evening
while seas similarly ease to 7-9 ft, with conditions continuing to
subside by the end of the week. With the persistent upper low
responsible for the repeated frontal passages finally moving
inland by the weekend and being replace by a building surface
high pressure over the northeastern Pacific this will see winds
return to a seasonable northerly pattern. /42-Picard
&&
.PQR WATCHES/WARNINGS/ADVISORIES...
OR...None.
WA...None.
PZ...Small Craft Advisory until 11 AM PDT this morning for PZZ210-
     251>253-271>273.
Small Craft Advisory from 2 AM to 11 AM PDT Tuesday for PZZ210-
     251>253.
Gale Warning from 11 AM Tuesday to 2 AM PDT Wednesday for PZZ210-
     251>253.
Small Craft Advisory from 11 PM this evening to 5 AM PDT Tuesday
     for PZZ271>273.
Gale Warning from 5 AM to 11 PM PDT Tuesday for PZZ271>273.
&&
$$
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NWS PQR Office Area Forecast Discussion