738 
FXUS66 KPQR 152239
AFDPQR

Area Forecast Discussion
National Weather Service Portland OR 
338 PM PDT Wed Oct 15 2025

.SYNOPSIS...A ridge of high pressure continues to facilitate dry 
conditions though much of Thursday across the interior valleys. 
Beginning later Thursday into Friday the pattern become more 
progressive starting with a weak frontal system ushering in chances 
for light rain or drizzle, more likely near the coast. Then high 
confidence of widespread rain for late Saturday into Sunday thanks 
to an upper-level trough. Likely drier conditions for the first part 
of next week, although some uncertainty remains with a 20-40% chance 
of rain returning by mid-week.  

&&

.SHORT TERM...Tonight through Saturday night...An upper level ridge 
over the NE Pacific extending into western Canada will slide south, 
dropping over the Pacific NW on Thursday. A few high clouds this 
evening will give way to mostly clear skies again overnight. 
Combined with light winds, expect temperatures to fall once again 
with patchy frost developing across rural valleys. Have issued a 
Frost Advisory for many of these locations once again through early 
Thu morning.  

A strong jet stream to the north will flatten out the upper ridge 
later Thursday, while increasing onshore northwesterly flow brings 
increasing clouds to the area by Thu afternoon. A weak front at the 
tail end of the system to the north will push onshore Thu evening, 
bringing potential for some light rain or drizzle across the area 
Thu night into early Friday morning. Overnight temperatures not 
expected to be as chilly. Should see mostly sunny skies returning by 
late afternoon with dry conditions expected through Fri night. 

Seasonable temperatures with afternoon highs in the lower to mid-60s 
continues into the weekend as broad upper level ridging transitions 
over the Pacific NW on Saturday. A more robust frontal system is 
expected to approach the region later Saturday. This system will 
bring increasing chances for rain to the coast by Saturday 
afternoon, with rain likely spreading inland later Sat evening 
through Sat night. More details in the long term discussion below.   

.LONG TERM...Sunday through Wednesday...An upper level trough is 
expected to move over the region on Sunday, though there is still 
uncertainty how deep this trough will be. This maintains a 
relatively large spread of potential rainfall accumulation amounts 
through Sunday night, though there is high confidence that higher 
amounts are more likely on the northern end of the forecast area 
than the southern ends. According to NBM guidance, the lower end 
rainfall amounts range between 0.2 to 0.8 inch (90% chance of 
exceeding), while the higher end amounts show anywhere from 1.5 
inches inland to 3.5 inches along the coast possible (10% chance). 
Showers likely behind a cold front that pushes across the area on 
Sunday. Latest guidance shows around a 15-20% chance of thunder at 
the coast Sunday afternoon. A few lingering showers possible into 
early next week as onshore flow persists. Active weather likely 
remains to the north through mid-week. But, long range models are 
indicating potential for this active weather to slide farther south, 
bringing a moderate risk of hazardous weather to western Washington 
and Oregon later next week. /02  

&&

.AVIATION...VFR conditions are expected to prevail for most of the
TAF period. High pressure over the region is expected to maintain
clear skies and light onshore flow 5-10 kt. An approaching cold 
front will increase chances for marine stratus to develop along 
the coast between 8-12z with a 50-80% chance of MVFR CIGs and 
30-40% for IFR CIGs. A slight chance for showers is also 
introduced around this time for KAST but given the low 
probability, have kept it VCSH. Winds turn southwesterly late 
tonight into Thursday as the cold front approaches. 

KPDX AND APPROACHES...Expecting VFR conditions to prevail through
the period. Northwest winds around 5 kt turning southwesterly late
tonight. /19

&&

.MARINE...Expect north to northwest winds to persist through 
Thursday morning while seas hold around 4-6 ft with a dominate 
period of 14-15 seconds. Conditions become more active Friday and
into the weekend as a large west to northwest swell enters the
waters. Wave heights are expected to increase to 10-12 feet Friday
evening with a period of 16-17 seconds, leading to steep seas and
dangerous conditions for Small Craft. As such, a Small Craft
Advisory for steep seas has been issued for all waters and the
Columbia River Bar starting at 5 pm Friday. Winds are not 
expected to be an issue with north to northwest winds 5-10 kt. The
pattern remains rather active through the latter half of the 
weekend into early next week as another, albeit stronger, frontal 
system progresses into the coast waters. Conditions will quickly 
amplify as a result with a 40-70% chance of seas greater than 15 
ft late Sunday into early Monday and a 30-50% chance for seas to 
exceed 18 ft across the outer waters during the same time frame. 
/19/99

.COASTAL...A large north to northwest swell of 10-12 ft at 16-17
seconds is expected to enter the waters Friday afternoon. This
will support a high threat for sneaker waves through much of
Saturday, possibly longer into Saturday night or Sunday as a
moderate threat. A Beach Hazards Statement has been issued for the
Central and Northern Coast of Oregon and the South Washington
Coast. Waves can run up significantly farther on a beach than
normal, including over rocks, logs, and jetties. Sneaker waves 
can suddenly knock people off of their feet and quickly pull them
into the frigid ocean which may lead to serious injury or 
drowning. Caution should be used when in or near the 
water. Always keep an eye on the waves, and be especially 
watchful of children.Remember, never turn your back on the ocean!
/19

&&

.PQR WATCHES/WARNINGS/ADVISORIES...

OR...Frost Advisory from 1 AM to 9 AM PDT Thursday for ORZ104-109-
     116>118-121.

WA...Frost Advisory from 1 AM to 9 AM PDT Thursday for WAZ205-208.

PZ...Small Craft Advisory from 5 PM Friday to 2 PM PDT Saturday for 
     PZZ210.

     Small Craft Advisory from 5 PM Friday to 8 PM PDT Saturday for 
     PZZ251>253-271>273.
&&

$$

www.weather.gov/portland

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