288
FXUS66 KPQR 262141
AFDPQR

Area Forecast Discussion
National Weather Service Portland OR
230 PM PDT Fri Jul 26 2024

.SYNOPSIS...Stable onshore flow will maintain fairly benign
weather with seasonably warm days and cool nights through early
next week. A passing system brings a chance for rain next Monday
into Tuesday. Models then hint at a warming trend mid to late
next week as high pressure builds back over the area.

&&

.SHORT TERM...Tonight through Sunday Night...Typical summer weather
today and through the weekend. Broad, weak troughing aloft with
stable westerly flow across the region. Some light haze from nearby
wildfire smoke, mainly east of I-5 will push back east of the
Cascades tonight as another surge of onshore flow moves across the
area. The main exception will be where near surface smoke is
confined to the immediate vicinity of ongoing fires in the Linn and
Lane County Cascades where LRAPA has issued an Air Quality Advisory
through Saturday afternoon. Afternoon highs expected in the lower to
mid 80s for the interior lowlands. Morning clouds from marine layer
intrusions into the inland valleys each night will help moderate
overnight temps a few degrees. Otherwise, mostly sunny skies
continue through Sunday. Breezy conditions will continue through the
central Columbia River Gorge Saturday and Sunday afternoon and
evening, with a renewed onshore push perhaps allowing for slightly
stronger winds gusting to around 25-35 mph in parts of Hood River
County. /DH

.LONG TERM...Monday through Friday...Still monitoring chances for
rain early next week. Models continue to speed up the timing of the
frontal system as a more well defined shortwave embedded within the
large scale trough crosses the region. Rain is likely to begin as
early as Monday morning for coastal areas, gradually spreading
inland through Monday night. PWAT values peak Monday afternoon
around 1.5 inches of precipitable water according to the ECMWF
ensembles. Regardless, ensemble and probabilistic guidance continue
to be rather bullish on the prospect of at least measurable rain
across the area, depicting around a 70 percent chance for northern
coastal areas and about a 50/50 shot for the Willamette Valley.
Meanwhile, the chance for as much as a quarter inch of rain sits
around 40-50 percent on the coast and 20-25 percent from Eugene to
Portland. Also expect slightly cooler temps again Monday into
Tuesday as this system crosses the region accompanied by increased
cloud cover and highs closer tot he upper 70s in the inland valleys.

WPC ensemble clusters continue depict a ridge of high pressure
developing over the western CONUS and a subsequent warming trend
mid to late next week. Guidance has backed off slightly for
highs next Wednesday, keeping temps closer to the mid 80s for
one more day before the chances to reach 90 degrees jump up to
around 70-80 percent in the inland valleys by Thursday and remaining
there through the end of next week. DH/CB

&&

.AVIATION...Currently VFR and clear skies throughout most of the
airspace. Expect VFR conditions to remain for inland terminals
throughout the TAF period, with clouds around FL045 developing
around 12-14Z Saturday. Chances of CIGs lowering to MVFR are
around 10-30% between 12-19Z Saturday. Otherwise, expect
sustained northwesterly winds around 7-12 kt with gusts up to 20
kt, lasting until 06-07Z Saturday.

Coastal terminals will begin to lower to MVFR/IFR CIGs around
03-06Z Saturday, likely persisting through the TAF period (20-30%
chance of IFR and 70-90% chance MVFR). Otherwise, expect
sustained northwesterly winds around 13-18 kt with gusts up to 25
kt, lasting until 06-07Z Saturday.

It should be noted that wildfires burning in the Central OR
Cascades (east of KEUG) as well as within the Columbia River Gorge
(east of KPDX and KTTD) could result in some slant range
visibility issues at times as smoke/haze spreads east of the
Cascades. However, predominately west to east flow should mitigate
these impacts.

PDX AND APPROACHES...VFR conditions and clear skies throughout
most of the period. Sustained northwesterly winds at 5-10 kt with
gusts up to 18 kt lasting until 05-06Z Saturday.
-JH

&&

.MARINE...A weak upper level trough will slowly meander eastward
through the weekend. Currently, expect persistent north/northwest
winds with low-end Small Craft gusts, primarily in our central
and southern waters. Threat will subside late tonight (Friday) and
seas will remain around 4 to 6 ft thereafter. Overall benign
conditions through the weekend with a southerly wind shift
expected late Sunday/early Monday.
-JH

&&

.PQR WATCHES/WARNINGS/ADVISORIES...

OR...None.
WA...None.
PZ...Small Craft Advisory until 2 AM PDT Saturday for PZZ252-253-272-
     273.
&&

$$

www.weather.gov/portland

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