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000
FXUS66 KPQR 251008
AFDPQR

Area Forecast Discussion
National Weather Service Portland OR
305 AM PDT Thu Apr 25 2024

.SYNOPSIS...Front will push inland today, with clouds and rain
through the day. Showers tonight through Sat am, then another front
will arrive with more rain for Sat afternoon into Sat night.
Unsettled weather with showers continues into early next week.

&&

.SHORT TERM...(Today through Saturday)...
Strong front still offshore as of 2 am, but rain has started across
parts of northwest Oregon into western Washington. As the front draws
closer, will see rain increase through mid morning. Will be a wet
cool day, with temperatures only in the 50s for the lowlands, and
30s/40s for the high Cascades where will see snow above 5000 ft.

Models still in good agreement with the front moving onshore late
this afternoon, and pushing across the region to the Cascades during
the evening. As it does, will see the steady rain transition to
showers, with showers continuing overnight.

For today through this evening, looks like will have a decent shot of
rainfall, with most areas getting 0.50 to 0.75 inch of rain. But, bit
more (1 to 2 inches) along the coast into the Coast Range and Willapa
Hills and parts of the Cascades from Mt Hood northward across the
south Washington Cascades. Speaking of the Cascades, snow levels will
stay somewhat elevated today into this evening, with new
accumulations of 3 to 7 inches of snow above about 5500 ft, though
could get as much as 8 to 12 inches on the higher peaks above 7000
ft. With the snow, and time of the year, will issue Winter Weather
Advisory for the Cascades for today through Fri evening.

Models have been persistent depicting a surface low drifting out of
the Gulf of Alaska towards the Pac NW later tonight through Fri, with
that low weakening as it moves inland near Astoria later Fri into Fri
evening. With this, showers will continue Fri/Fri evening. Snow
levels remain at 4500 to 5000 feet, with another 3 to 8 inches in the
Cascades Fri into Fri evening.

Next system will be fast approaching on Sat. The morning may be
mostly dry, but will still have some lingering showers about the
area. As the front approaches, rain will increase along the coast by
mid-day, with that rain spreading inland in the afternoon. Again,
this will be a fast moving front, with front moving across the region
early Sat evening, with rain transitioning to showers. With fast
movement, does not look like will get a lot of rain, with most areas
in the 0.15 to 0.33 inch range, though few spots (such as the Coast
Range/Willapa Hills) could get 0.50 to 0.75 inch./Rockey

.LONG TERM...(Sunday through Wednesday)...Pattern is rather
progressive, with fronts moving off the northeast Pacific into
the Pacific NW. Yet another front will push across the region
Sunday night, with post-frontal showers on tap for Monday. Still
a bit cooler than that expected for late April, with overall
temperatures in the lowlands in the 50s to lower 60s. Snow
levels will run 2500 to 3500 ft, which will maintain some snow
at times for the higher terrain of the foothills, as well as
most of the Cascades.

Few showers around region on Tuesday, but think most of the day will
wind up being mostly dry, as will have weak ridging over the region.
But, models show another potent front offshore later Tue night/early
Wed, with that front pushing inland on Wed. With this, does look to
be more rainy that showery for Wed. As such, will adjust forecasts to
reflect this trend. After that, models still in quite a bit of flux.
Prior runs were showing upper low dropping southward towards north
Calif (remaining just offshore of Oregon/Washington). Most recent
runs indicate that this low will stay off the Pac NW coast, and drift
inland next Fri. So, will just keep next Thu/Fri unsettled with
showers.                           /Rockey

&&

.AVIATION...Latest satellite, radar, and mesoanalysis observations
as of 230 AM PDT depicts a warm front lifting offshore of the
Pacific Northwest, bringing rain, IFR cigs, and MVFR visibility
to the coast. Expect predominately MVFR cigs in the Willamette
Valley and IFR cigs at the coast through the TAF period as the
frontal system pushes inland today. Similar to what is already
happening at the coast, light to moderate rainfall may also bring
visibility down to MVFR thresholds for inland terminals at times
today (20-40% chance). Winds will be south-southwesterly today
across all terminals with gusts to 25-30 kt along the coast and
20-25 kt in the Willamette Valley.

Notes: The ASOS at KTTD is only available via the dial in option.
The AWOS at KMMV is still out of commission. There is no
estimated time of repair.

PDX AND APPROACHES...Predominately MVFR cigs through the TAF
period as a frontal system pushes inland. Visibility could drop
to MVFR thresholds at times with steady, moderate rain. Southerly
winds will be around 10-15 kt today. Gusts to 20-25 kt will
between 20z Thu - 03z Fri during the frontal passage. Guidance
suggests a 10-20% chance of IFR cigs through 00z Fri. -Alviz

&&

.MARINE...Mesoanalysis as of 230 AM PDT depicts a warm front
lifting over the waters early this (Thu) morning, bringing rain
and southerly winds. Expect winds to gradually strengthen this
morning as the trailing cold front pushes through. The current
Small Craft Advisory remains on track as there is high confidence
that the waters will see southwesterly winds gusting to 25-30 kt
today. Occasional gusts to 35 kt are possible for all waters with
the cold frontal passage between 11 AM-3 PM (40-60% chance). Since
any gale force gusts will likely be sporadic and temporary, a
Gale Warning was not issued. Seas will be choppy and build to
around 7-9 ft at 8-9 seconds.

Winds turn more westerly/northwesterly Thursday night into Friday
as the low pressure system pushes inland. Winds begin to ease
slightly with gusts to 20-25 kt. However, a westerly swell will
enter the waters and build seas to around 9-11 ft. These elevated
seas are brief, as the swell height falls Friday night to
Saturday. The next frontal system arrives on Saturday, will return
gusty southwesterly winds. The latest NBM shows a 20-30% chance of
gale force wind gusts of 34 kt or greater across the waters
Saturday.    -Alviz

&&

.PQR WATCHES/WARNINGS/ADVISORIES...

OR...Winter Weather Advisory for North Oregon and Lane County
       Cascades above 4500 feet for this afternoon through Fri
       evening.

WA...Winter Weather Advisory for South Washington Cascades above
       4500 feet for this afternoon through Fri evening.

PZ...Small Craft Advisory from 5 AM early this morning to 2 AM PDT
     Saturday for PZZ210-251>253-271>273.
&&


$$

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