NWS Portland, OR wrote its last area forecast discussion before the first event at Jul 22, 1:25 PM PST, 2 hours 36 minutes earlier.
Area forecast discussion, Jul 22, 1:25 PM PST, 2 hours 36 minutes before
Area Forecast Discussion
National Weather Service Portland OR
225 PM PDT Sat Jul 22 2023
.SYNOPSIS...Another dry and warm day on tap for Sunday. Then, a
brief break in our summer weather, as will have a front shifting
across the region Monday and Monday night. This will bring cooler
temperatures with clouds and even some spotty showers. Highest
potential for measurable rain will be north of Lincoln City to
Portland line. Then, back to dry and mild for rest of next week,
with temperatures just a tad below those typical for late July.
&&
.SHORT TERM...Tonight through Tuesday...Another great mid-summer
late afternoon/evening across the region, with sunshine and warm
temperatures, though tad cooler along the coast. Should see
temperatures fall back to the lower 80s by sunset, and 70s soon
after. High pressure will hold the warm and dry conditions for one
more day, as Sunday will be near carbon copy of Saturday.
Then, some changes. A front will offshore will be approaching. As it
does, surface high pressure will shift to the coast, and inland
Sunday night. This will bring increasing onshore flow Sunday night
into Monday am, with marine stratus spreading along the coast, and
to some degree across the interior. Will see spotty drizzle along
the coast during that time.
But, the front will be a bit slower to push into the region. Current
models continue to indicate the front will push across the region
later Monday afternoon into Monday night. Suspect this trend more
apt, considering it will have to push up against the upper high over
the western USA. So, will see increasing chance of showers as Monday
progresses. Based on current trends, will go with cloudy skies along
the coast, with occasional drizzle, then increasing showers,
especially north of Tillamook. But, further inland, areas of morning
marine stratus will give way to partly cloudy skies. Then, as the
front draws closer, will see increasing clouds again in the
afternoon, along with some showers. Front should shift across the
region Monday night, with moderate to strong onshore flow in its
wake. Most likely time for any showers will be Monday night. Models
have been consistent in showing most of the precipitation stays
north of a Newport to Salem line. Generally, a few drops to maybe
0.10 inch for areas from that prior mentioned line north to the
Columbia River,, and 0.10 to 0.25 inch from the north Oregon Coast
Range northward into western Washington. Onshore flow means it will
be breezy in the mid/east Columbia River Gorge and areas to the
east, with west winds gusting 25 to 35 mph Mon afternoon/evening.
Have lowered high temperatures for Monday, with inland highs only in
the middle 70s inland valleys, and lower to middle 60s along the
coast. However, depending on depth and marine layer effects, this
may be too high. Would not be surprised if only can reach lower 70s.
Will look at this bit more with tonight and Sunday model trends.
Either way, lot cooler than has been.
Thanks to the onshore flow, should see good deal of marine stratus
across the region on Tuesday. But, with surface ridge rebuilding
offshore, do think the clouds will gradually break apart in the
afternoon, though will take time. Still have potential for a few
light showers, as the marine layer overturns and mixes. But, not
much in way of precipitation expected. Still cool, with highs in
the 60s along the coast, and mid to upper 70s inland. /Rockey
.LONG TERM...Wednesday through Friday...High pressure over the region
will maintain varying degrees of onshore flow next week. Model
guidances showing daily high temperatures for much of the interior
stay relatively close to that typical of late July, with highs 80 to
85, with 65-75 along the coast. But, still dry. /Rockey
&&
.AVIATION...VFR with light winds for all inland locations through
the next 24 hrs. Along the coast, expect a clearing of skies this
afternoon and into the evening as the low level marine layer
dries out. Low level stratus will return between 08-10z Sun for
some areas along the coast and last till late morning.
For detailed Pac NW aviation weather information, go online to:
http://weather.gov/zse
KPDX AND APPROACHES...No concerns. VFR with clear skies throughout
the forecast period. /BMuhlestein
&&
.MARINE...High pressure remains over the offshore waters which will
maintain north to northwest winds around 5 kt through Sunday. Seas
stay in the 2 to 5 ft range. A frontal system associated with an
upper level low currently over the Gulf of Alaska will move
northeast across the waters Monday into Tuesday. Winds will
strengthen directly ahead of the front reaching around 20 kt
sustained. Not expecting any postfrontal convection so winds will
drop off abruptly after passage. Small Craft Advisories are likely
Monday possibly into Tuesday. /BMuhlestein
&&
.PQR WATCHES/WARNINGS/ADVISORIES...
OR...None.
WA...None.
PZ...None.
&&
www.weather.gov/portland
Interact with us via social media:
www.facebook.com/NWSPortland
www.twitter.com/NWSPortland