Richland, Virginia 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

575
FXUS66 KPDT 122320
AFDPDT

Area Forecast Discussion
National Weather Service Pendleton OR
320 PM PST Wed Feb 12 2025


.SHORT TERM...Wednesday through Friday Night...

1) Winter Weather Advisories Thursday-Friday in many areas in Oregon
2) High Wind Warning in foothills and Southern Grand Ronde Valley
   Thursday
3) Warming trend going into the weekend

Satellite imagery depicts clear conditions over the region as a dry
air mass is situated over the PacNW. A trough extending over the
Four Corners is allowing northern flow to continue to bring the
cool, dry air mass into Thursday. Lows overnight Wednesday into
Thursday will continue to stay in the single digits for most of the
Columbia Basin and as low as -15 degrees in some places of the
higher elevations located in the Blue Mountains. These low
temperatures will keep our already active Cold Air Advisory in the
mountains, Foothills of the Blues, and Central OR valid until 7AM on
Thursday. A transient ridge will set in overnight Wednesday into
Thursday after the trough continues to move towards the central
plains. Winds aloft will shift more westward, putting a break into
the cold-dry airmass pumping into the region and allow Lows/Highs to
trend warmer towards the weekend.

A closed-off low offshore of OR/WA moves onshore into the region
Thursday morning headed into Thursday afternoon. A flow shift to
SW/WSW aloft at 500mb will be accompanied with increased moisture
advection and precip chances. Precip will emerge from south to
north, beginning in Deschutes County in early morning Thursday.
Light snow will then roll through the Southern Blue Mountains
shortly after, and eventually the entire CWA by late afternoon.
Current thinking for Thursday morning to Friday morning is high
confidence (70-90%) in 2-4" across the lower elevations including
Grande Ronde Valley and the John Day Basin, 3-7" across the Ochoco
and John Day Highlands, and 5-10" across the east slopes of the OR
Cascades and Blue Mountains. Given that confidence is good (70-90%)
that snow amounts will exceed minimum Winter Weather Advisory
criteria, advisories have been issued for the aforementioned.
Additionally, the pressure gradient tool gives us high confidence
(70-90%) owing to a >8 MB difference between BKE and MEH between 13Z
and 17Z Thursday seen across guidance. This supports increasing
winds to 35-45 mph in the Southern Grand Ronde Thursday morning into
the late afternoon, with gusts as high as 45-65 mph. The foothills
of the Southern Blue Mountains will see similar windy conditions at
35-45 mph, with gusts up to 50-60 mph. A High Wind Warning is issued
for these areas until 10PM Thursday. The combination of falling and
blowing snow with these winds will promote hazardous driving
conditions, including low visibilities/whiteout conditions at times,
more likely than not across the southern Grande Valley interstate
corridor.

Light snow will continue to fall through the Columbia Basin, with no
more than an additional half inch expected on Friday. OR Cascades
and Blue Mountains will continue to support Winter Weather
Advisories through Friday. Latest NBM guidance Friday morning-
Saturday morning show 40-60% of exceeding 5 inches in Northern Blue
Mountains and >90% chance in east slopes of OR Cascades.



.LONG TERM...Saturday through Wednesday...

Synoptic Overview: Ensemble NWP is in good, though not excellent,
agreement regarding the 500-mb pattern through Tuesday. Guidance
depicts a transient ridge overhead Saturday AM, resulting in mostly
dry weather outside of the mountains where lingering light snow is
forecast beneath a northwesterly flow aloft. By Saturday PM, active
weather returns with southwesterly flow aloft ushering in a warmer
air mass and rising snow levels. Another shortwave then likely (80%
confidence) rounds the parent upper low and swings through Sunday
through Monday, switching flow aloft to westerly then northwesterly.
Drier weather (aside from linger precipitation for the mountains)
returns Tuesday as another ridge of high pressure likely (80%
confidence) moves over the PacNW. Wednesday, ensemble solutions
begin to diverge with roughly 65% showing some flavor of
southwesterly flow aloft and offshore troughing with wet weather,
while the remaining 35% show a drier scenario.

Snow chances: NBM probabilities suggest a low chance (15% or less)
of advisory-level snowfall (2-3") across the lowlands during the 48-
hr period ending Monday morning. The Cascades and northern Blues
have a significantly higher chance of advisory-level (5-6") snow (50-
80%). Plunkett/86

&&

.AVIATION...00Z TAFs...VFR conditions will likely persist (90%
chance or greater) for all sites through the remainder of today and
into tonight. An incoming weather system will facilitate increasing
mid/high cloud cover late afternoon through the night. Snow will
spread from southwest to northeast beginning around 12Z Thursday
(BDN/RDM) reaching DLS/PDT/ALW/PSC/YKM by 16-20Z. MVFR or lower
CIGs/VSBYs are likely (80-90% chance) at BDN/RDM/DLS by early
Thursday morning, with sub-VFR CIGs/VSBYs becoming more likely than
not (>50% chance) for other sites by 18-20Z Thursday.

Sustained winds of 12 kts or less are forecast for all sites, though
gusts to 15-25 kts are likely (80% chance) at DLS this afternoon and
evening. Gusts of greater than 15 kts are unlikely (<20% chance) for
all other sites. Plunkett/86


&&


.PRELIMINARY POINT TEMPS/POPS...
PDT   4  24  18  34 /   0  80  60  90
ALW   6  25  21  32 /   0  80  80  90
PSC   6  28  20  35 /   0  80  60  60
YKM   6  25  18  35 /   0  60  40  10
HRI   4  26  17  35 /   0  80  60  70
ELN   4  24  18  36 /   0  60  30  20
RDM   3  31  15  40 /  10  90  60  30
LGD  -1  29  22  37 /   0  80  70  90
GCD   3  33  23  40 /   0  90  70  80
DLS  11  27  20  40 /   0  80  60  50

&&

.PDT WATCHES/WARNINGS/ADVISORIES...
OR...Winter Weather Advisory from 7 AM Thursday to 10 AM PST Friday
     for ORZ041.

     Winter Weather Advisory from 7 AM Thursday to 4 PM PST Friday
     for ORZ044-508.

     Cold Weather Advisory until 7 AM PST Thursday for ORZ049-050-502-
     503-506-509-511.

     High Wind Warning from 10 PM this evening to 10 PM PST Thursday
     for ORZ049-507.

     Winter Weather Advisory from 7 AM Thursday to 10 PM PST Friday
     for ORZ049-502-503-507.

     Winter Weather Advisory from 4 AM Thursday to 4 PM PST Friday
     for ORZ505-506.

     Winter Weather Advisory from 1 AM Thursday to 4 PM PST Friday
     for ORZ509.

     Winter Weather Advisory from 4 AM Thursday to 10 AM PST Friday
     for ORZ510.

     Winter Weather Advisory from 1 AM Thursday to 10 AM PST Friday
     for ORZ511.

WA...Winter Weather Advisory from 7 AM Thursday to 10 AM PST Friday
     for WAZ024.

     Cold Weather Advisory until 7 AM PST Thursday for WAZ030-522.

     Winter Weather Advisory from 7 AM Thursday to 10 PM PST Friday
     for WAZ029-030.

&&

$$

SHORT TERM...95
LONG TERM....86
AVIATION...86