630
FXUS66 KPQR 181001
AFDPQR

Area Forecast Discussion
National Weather Service Portland OR
301 AM PDT Wed Sep 18 2024

.SYNOPSIS...Upper low will pass to the south today, with lingering
clouds, mainly to south and east of Salem. Otherwise, high pressure
will return, with dry weather and bit below seasonal temperatures
under variable onshore flow. Another front will bring a chance of
showers Sunday into Monday. Does appear will see warmer temperatures
next week, maybe as much model uncertainty at this time.
&&

.SHORT TERM...Now through Friday...
Upper low pressure off the ORCA (Oregon/Calif) border this am. As of
3 am, still a few showers over far south Lane county, but bulk of the
showers are farther to the south and east with better clockwise
circulation around the low. Meanwhile, high pressure building from
the offshore into Washington and far northern Oregon. As the day
progresses, will see the upper low sink farther to the south, with
high pressure building into Oregon. With this, will see shower threat
come to an end, with clouds gradually giving way to partly to mostly
sunny skies. Will be warmer, with temperatures back into the 60s
along the coast, and upper 60s to lower 70s across the interior.

Not much change tonight into Friday, as will maintain high pressure
offshore. As such, will have variable light to moderate onshore flow.
Overall, rather pleasant late September weather, with patchy fog/low
clouds for overnight/early morning hours along with overnight lows
mostly in the upper 40s to lower 50s. Days will be quite pleasant,
with highs in the 60s along the coast, and lower to middle 70s
farther inland.                         /Rockey

.LONG TERM...Saturday through Tuesday...
Forecast confidence remains below normal this weekend into the early
part of next week as model solutions continue to diverge
significantly with regard to how the upper level pattern evolves.
Ensemble clusters remain just about evenly split in depicting
ridging, troughing, and zonal flow regimes over the Pacific
Northwest from Saturday through Monday. This obviously will have
large implications for the forecast as anything ranging from
warm and dry weather to a cooler and wetter pattern remains on
the table for days 5-7. This continues to be reflected in the
NBM interquartile ranges for temperatures which range anywhere
from the upper 60s to the upper 70s between the 25th and 75th
percentile guidance. As such, and until models begin to converge
on a solution, have opted to stick with the NBM mean which
splits the difference between these solutions and depicts broad-
brushed chance to slight chance PoPs over the area late this
weekend through early next week.      /CB
&&

.AVIATION...MVFR cigs prevailing across the region with areas of
IFR along the coast. An upper level low now off the south Oregon
coast continues to track southward today. Light showers wrapping
around the low is clipping Lane county as of 09Z Wed. Showers
expected to diminish overnight. MVFR is expected (70-90% chance)
to continue through 15Z Wed, then chances begin to decrease with
VFR most likely after 18Z Wed. Winds light and variable, becoming
northwest 6 to 10 kt with gusts to 15 kt this afternoon. Generally
VFR inland overnight into Thursday morning, but can expect some
patchy fog, but low MVFR to IFR to return to the coastline 03-05Z
Thu.

PDX APPROACHES...MVFR cigs 1500-2500 ft in the area is expected
to improve to VFR after 18-19z Wed. Winds light and variable
overnight, before becoming northwest 6-8 kt by Wed afternoon.
/mh /DH

&&

.MARINE...High pressure returns to the coastal waters today as the
system from Tuesday departs to the south. As a result will see
northerly winds return today and continue through the week. Winds
may gust 20 to 25 kt at times, primarily over the outer zones. The
high pressure should weaken over the weekend, as will winds.

Seas around 6 ft today increasing to around 8 ft later tonight
into into Thursday, then settling to around 5 ft late in the week.
/mh

&&

.PQR WATCHES/WARNINGS/ADVISORIES...

OR...None.
WA...None.
PZ...None.

&&



$$

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