Mt. Hood Meadows

000
FXUS66 KPQR 301115
AFDPQR

Area Forecast Discussion
National Weather Service Portland OR
415 AM PDT Fri Oct 30 2026

.SYNOPSIS...Cool and showery conditions continue through Friday as 
an upper-level low sits offshore. Clear skies and calm winds may 
bring frost or fog development across much of NW OR and SW WA in the 
mornings Saturday through Monday. Mostly dry conditions return this 
weekend. More uncertainty for the return of precipitation early next 
week with limited weather impacts expected.

&&

.DISCUSSION...through Thursday...Water vapor satellite imagery early 
Friday morning shows a vertically stacked low pressure system 
spinning off the Washington coast. Expect rain showers to increase 
in coverage across the area later this morning as a shortwave 
impulse lifts over NW Oregon into SW Washington. Accumulations at 
most locations today will likely see only a trace to 0.10 inch, but 
there is around a 20% chance that heavier showers bring over 0.25 
inch to some areas. Chances for precipitation decrease to below 10% 
by Friday evening, except 10-30% along the north OR/south WA coast.  

A northerly jet streak on the back side of the upper low will dig 
late Friday causing the upper level pattern to stretch into an 
elongated trough near the coast while the surface low drifts south 
and weakens offshore on Saturday. This will largely reduce 
precipitation chances for much of Saturday. But, as the trough moves 
over the region, some wrap around moisture will bring around a 10-
30% chance of light rain or sprinkles across the Willamette Valley 
for Saturday evening, with higher chances over the Cascades. As the 
upper trough slides east of the Cascades on Sunday, an upper level 
ridge of high pressure will begin to build over the region leading. 
to dry conditions.  

Sky cover Friday night into Saturday morning will be an important 
factor in overnight temperatures potentially falling to near or 
below freezing. Latest model guidance suggests clear to partly 
cloudy skies over inland valleys along with calm winds should allow 
for radiational cooling to occur. Outside of the major metro areas, 
there are high chances for minimum temperatures to fall below 
freezing. Will maintan the Freeze Watch and Frost Advisories in 
place for Fri night into Sat morning. Afternoon temperatures are 
expected to warm into the lower to mid-50s on Saturday before 
falling back into the 40s Sat evening after sunset. Similar 
overnight low temps are likely Sat and Sunday nights, however, 
freeze and frost headlines are only issued during the growing season 
of April 1 through October 31. Therefore, no additional freeze or 
frost headlines will be issued after Saturday. 

Ensemble guidance is in relatively good agreement that upper level 
ridging over the region maintains dry conditions into early next 
week. But, there remains a few solutions that shift the ridge far 
enough east allowing for low chances of preciptation to persist late 
Monday into Tuesday. If the drier solutions pan out, expect a slight 
warming trend with afternoon highs near 60 degrees through the 
middle of next week. Chances for rain increase again by Thursday as 
there is increasing confidence for a frontal system to approach the 
area. At this point, no significant impacts are expected with the 
upcoming weather pattern. /DH

&&

.AVIATION...Through 12Z Saturday...Moist, southwest flow aloft
will persist through this evening as low pressure remains
offshore. As of 10z Friday, IFR to LIFR CIGs persist across the
southern and central Willamette Valley, while radar imagery is
showing light rain showers beginning to redevelop. This will
likely bring more widespread MVFR conditions through the
Willamette Valley, around a 40-80% chance for CIGs below 3 kft,
highest near KSLE where there is around a 50-60% chance for IFR
conditions to persist through 18z. Showers are then expected to
decrease in coverage later this afternoon and evening, with
conditions favoring VFR by 18-21z Friday. Winds generally remain
south to southeast 10 kt or less. 

KPDX AND APPROACHES...VFR conditions are favored through the
period. But rain showers increasing this morning will bring around
a 30% chance for MVFR CIGs at any given hour between 14-20z 
Friday. Dry conditions expected by 02z Saturday. Light winds are
expected to become southeasterly around 4-7 kt. /DH

&&

.MARINE...Low pressure will continue to weaken as it drifts south
off the Oregon coast through Saturday. Southerly winds increase
again Friday afternoon, but should generally remain 20 kt or 
less. Winds then weaken over the weekend. Seas around 5 to 6 ft 
today gradually subside to around 4 ft on Saturday. Offshore winds
develop late Sunday and persist into early next week. A long 
period west-northwest swell also arrives building seas to around 8
to 11 ft on Monday. Chances for seas over 10 ft on Monday remain 
at around 40-60% across the outer waters. The next frontal system 
likely approaches the waters mid to late next week. /DH 

&&

.PQR WATCHES/WARNINGS/ADVISORIES...

OR...Frost Advisory from midnight tonight to 9 AM PDT Saturday for 
     ORZ101>103-107-108-111>113-119-124-125.

     Freeze Watch from late tonight through Saturday morning for 
     ORZ105-109-114-115-123.

WA...Frost Advisory from midnight tonight to 9 AM PDT Saturday for 
     WAZ203-204-206-207.

     Freeze Watch from late tonight through Saturday morning for 
     WAZ205.

PZ...None.

&&

$$

www.weather.gov/portland

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