Vancouver, Virginia 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

329
FXUS66 KPQR 201800
AFDPQR

Area Forecast Discussion
National Weather Service Portland OR
1100 AM PDT Sun Jul 20 2025


.SYNOPSIS...After seasonable temperatures today and Monday and
scattered showers developing overnight and Monday, expect
temperatures to warm well above average midweek before trending
back towards average levels by next weekend.


&&


.SHORT TERM...Now through Monday...Water vapor satellite imagery
this morning reveals a broad low amplitude shortwave trough
sagging southward over the Pacific Northwest. An embedded vort
max is located just off Vancouver Island and dropping south-
southeastward towards the region. Large scale lift ahead of
these features is producing plenty of mid and high level cloud
cover over the region. Composite radar reflectivity is
highlighting light returns spreading across much of the region.
This should remain mainly virga through the afternoon hours.

Satellite imagery also shows elevated convection firing in the
vicinity of the aforementioned vort max along the western edge
of Vancouver Island. Guidance has come into good agreement this
vort max will move squarely over northwest Oregon and southwest
Washington this evening and overnight. This will aid in the
development of scattered high based showers spreading across the
region. For example, 90% of the EPS membership, nearly 70% of
the AIFS ensemble membership, 80% of the GEFS, and 50% of the
GEPS membership produce at least some rain at KPDX at some point
between this evening and Monday. The number of members
producing QPF have also jumped in both the HREF and REFS
membership as well. Needless to say, the likelihood that many
areas in southwest Washington and northwest Oregon, particularly
north and east of Salem will experience rain showers overnight
into Monday appears dramatically higher than it did 24 hours
ago. In fact, NBM guidance suggests a 10-30% chance of 0.25" of
rain falling over the next 24 hours at any given location north
of a line extending between Clatsop County and Clackamas County
with the highest probabilities centered over the south
Washington Cascades between Mt St Helens and Mt Adams. Certainly
most areas will not receive that amount of rain, but those that
do will certainly benefit and this will help to temporarily
reduce fire danger.

It should be noted that model soundings indicate elevated
instability will approach the necessary depth to be capable of
allowing for charge separation and lightning. Given the weak
flow in the vicinity of the vort max and the surface appears
likely to be decoupled from the convection do not foresee
needing any fire weather highlights since strong outflow winds
and sufficient lightning coverage seem both unlikely.
Nonetheless, any lightning that does develop could result in
fire starts, particularly in the form of holdovers as we dry out
and warm up Tuesday into Wednesday. /Neuman


.LONG TERM...Monday Night through Saturday...The global
ensembles are in good agreement 500mb heights will build in the
wake of the tonight/Monday storm (I say that loosely) system
and inland temperatures will warm Tuesday into Wednesday. This
will result in temperatures climbing back into the upper 80s to
low 90s for inland valleys. This has pushed areas from Salem
northward into Clark County and eastward through the Gorge into
Moderate Heat Risk (level 2 of 4) for Wednesday. The good news
is that the potential for unusually hot temperatures (95F or
warmer) is generally 10% or less for the Willamette Valley on
Wednesday when temperatures appear most likely to peak.

While the ensembles are in general agreement weak and broad
upper level troughing will then gradually lower 500mb heights
over the Pacific Northwest late in the week into early next
weekend and result in cooling temperatures, there is
considerable uncertainty around a small cutoff upper level low
pressure that tries to develop off the California coast Tuesday
into Wednesday. Initially, this will not impact our weather
significantly, but it could impact our weather, particularly
with regards to thunderstorm potential over the Lane and Linn
County Cascades Thursday and Friday. The global ensembles
(particularly the EPS membership) have shunted convection
chances farther south and east of the region late in the week as
this weak upper level low pressure gets absorbed into the flow
well south and east of the region during that timeframe or it
just remains off the California coast indefinitely. As a
result, the below mentionable (<15%) PoPs and thunderstorm
chances produced by the NBM seem on track for now, but this
feature will still be worth monitoring as small scale shifts in
the synoptic pattern can have fairly dramatic impacts on the
track of a mesoscale feature like this 4-6 days in advance. /Neuman


&&


.AVIATION...An upper level trough moving through the PacNW will
produce mid to high level BKN and OVC clouds across the region,
clearing by 06-12z Monday. MVFR marine stratus continues along the
coast from KAST and northward, dissipating between 18-21z Sun as
daytime heating progresses. There`s a 30-60% chance of more
widespread MVFR stratus returning along the coast after 05-09z
Mon. Inland, predominately VFR conditions expected through the TAF
period, with a 30-50% chance of MVFR ceilings developing after
10-14z Sun, better chances in the southern Willamette Valley.
Light rain showers possible after 00z Sun along the coast and
06-15z Sun inland north of KSLE. Winds north to northwest less
than 10 kts.

PDX AND APPROACHES...Predominately VFR through the TAF period with
high clouds. Light rain showers possible 06-15z Sun with a 20-30%
chance of MVFR ceilings. Expect northwesterly winds around 4-7
kt. -HEC


&&

.MARINE...Benign weather expected across the waters this weekend
into early next week. High pressure will maintain northerly to
northwesterly winds, generally less than 10 kts. Expect wave
heights of 2-4 feet. These wind and wave conditions are forecast
to continue through at least mid-week.       -Alviz/HEC

&&

.PQR WATCHES/WARNINGS/ADVISORIES...
OR...None.
WA...None.
PZ...None.


&&

$$

www.weather.gov/portland

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