National Weather Service Weather Forecast Office

• Home
• Site Map
• News
• Organization
• Search for: NWS All NOAA 

000
FXUS66 KPDT 150322
AFDPDT

Area Forecast Discussion
National Weather Service Pendleton OR
822 PM PDT Sun Apr 14 2024

.UPDATE...
Latest radar imagery showed that all of the thunderstorms over
eastern Oregon have dissipated, and now there were just showers.
However, there are still some thunderstorms in western Idaho that
were moving southwest. These were also weakening, but if they hold
together could reach Wallowa County. However, the overall trend
continues to be downward on the precipitation with everything
continuing to weaken during the overnight hours.

Winds will increase during the overnight hours and into Monday,
especially over the Columbia Basin of Oregon, Kittitas Valley,
Simcoe Highlands, Columbia Gorge and Blue Mountain Foothills.

The increased winds will help keep overnight lows up and based on
the latest guidance, have raised temps overnight in many
locations.

&&

.AVIATION...
06Z TAFS...High confidence in VFR conditions (100%) through the
TAF period. Breezy winds are either occurring or will develop
during the overnight hours into Monday with gusts 25 to 30 kts at
all sites and 30 to 35 kts at DLS. Confidence is high (90-100%).

&&

.PREV DISCUSSION... /issued 340 PM PDT Sun Apr 14 2024/

Updated for Aviation...

AVIATION...
00Z TAFS...VFR conditions are expected over the TAF sites through
the TAF period. Isolated SHRA/TSRA are expected through the
evening hours, but should remain east of the TAF sites. The 2
sites that have a low (<30%) chance of seeing any SHRA/TSRA are
ALW and PDT. After this evening, any chances drop to zero.

Breezy winds will overspread the region though Monday, with wind
gusts mainly 25 to 30 kts at all sites and up to 35 kts at DLS.

PREV DISCUSSION... /issued 137 PM PDT Sun Apr 14 2024/

SHORT TERM...Today through Tuesday...A low pressure system,
centered over central California this afternoon, continues to
influence our weather via warm air advection from the Great Basin
and subtle moisture flow along the mountains bordering the eastern
and southern end of the forecast area. Seeing some convective
activity develop right along where Grant and Crook County border
Harney, as well as some cumulus development stretching from the
northern Blues down toward central Oregon. We`ve stayed dry thus
far, as moisture has been lacking, but as the low continues its
gradual eastward movement, more favorable moisture advection will
take place, allowing for more convective activity to pop up along
primarily the eastern mountains. Latest CAMs support this, however
expectation is that storms will be on the weaker end, with the
wetter, stronger cells lying to our southeast. Precip will then
abate by midnight as the forecast area finds itself between systems.

This transitory period between systems will beget windy conditions
for the forecast area, primarily through the Cascade Gaps and the
Oregon Basin. Wind Advisories remain in effect, with onset time
differing based on how the synoptic pattern evolves. Winds this
evening will increase, more so than they already have, across the
Cascade Gaps as the California low pushes toward the intermountain
west, leaving us under an area of diffluence aloft as a trough
over western Canada glances us to the north. Gusty winds
downstream of the Cascade Gaps are more likely during the day
Monday as the Canadian trough swings a cold front through the CWA.
The central Washington Cascades may see some light snow above
3500 ft, but main concern will be winds gusting up to 50 mph
across the Kittitas Valley, Simcoe Highlands, and Columbia River
Gorge as the front moves in. Gusts will also approach 45 mph
through the Oregon Basin. Blowing dust may occur during the day
Monday across the Oregon Basin as a result of these strong winds.

We`ll remain breezy heading into Tuesday as a jet max lies overhead
on the southern flank of the Canadian trough, but gusts will
decrease down towards the 30-35 mph range across the advised areas.
Light mountain precip will linger, but amounts are expected to be
minimal. Main concern toward the tail end of the period will be
monitoring the potential for an overnight freeze as the region`s
growing season begins to burgeon. Most likely suspects would be the
Kittitas and Yakima Valleys, as well as the foothills of the Blues,
as the area finds itself under amplified NW flow and cold air
advection on the back end of the Canadian trough. Elsewhere, high
temps will cool into the 60s and 50s across our population centers
through the start of the work week under this colder pattern.
Evans/74

LONG TERM...Wednesday through Sunday...A deep upper level low
pressure system over central Canada will maintain a cyclonic flow
over the PacNW Wednesday and Thursday providing the continued threat
of some showers mainly over SE WA and NE OR. On Friday the low
pressure system moves further east allowing an upper level ridge of
high pressure to begin moving into the PacNW from the eastern
Pacific for the weekend. Ensemble models show a deep upper level
trough in the Gulf of Alaska sending a shortwave trough towards the
PacNW over the weekend pushing the ridge axis off to the east thus
indicating a weak trough influencing the forecast area by late
Saturday into Sunday. Deterministic models are showing more of a
range from an outright weak shortwave passage to a closed low
pressure passing over the region. Overall forecast confidence good
through Friday but decreases going through the weekend as models are
not in good agreement on how to handle this weak trough feature.

AVIATION...18Z TAFS (Previous Discussion)...VFR conditions
expected over the next 24 hours with some showers and possible
thunderstorms stretching from central Oregon through NE Oregon
through this evening but not expected to impact TAF sites other
than some possible VCSH around RDM and BDN. RDM and BDN will see
some SCT- BKN070-120 with other sites seeing SCT-BKN120. Breezy
winds have already begun spreading into the region, with
widespread gusts 20-30 knots by this afternoon continuing into
Monday when winds reach their peak 15-30kts gusts 30- 40kts.

&&

.PRELIMINARY POINT TEMPS/POPS...
PDT  46  59  34  55 /  20   0   0   0
ALW  46  63  38  58 /  10   0   0  10
PSC  49  68  41  61 /   0   0   0   0
YKM  48  64  35  59 /   0   0   0   0
HRI  47  63  38  60 /   0   0   0   0
ELN  45  56  33  54 /   0   0   0   0
RDM  39  53  29  56 /   0   0   0   0
LGD  45  57  32  54 /  40   0   0   0
GCD  36  57  30  58 /  60   0   0   0
DLS  49  59  42  59 /   0   0   0   0

&&

.PDT WATCHES/WARNINGS/ADVISORIES...
OR...Wind Advisory until 11 PM PDT Monday for ORZ041-044-510.

     Wind Advisory from 5 AM to 11 PM PDT Monday for ORZ507-508.

WA...Wind Advisory until 11 PM PDT Monday for WAZ024-026-521.

&&

$$

SHORT TERM...77
LONG TERM....91
AVIATION...77