Area Forecast Discussion
Issued by NWS Pendleton, OR

Current Version | Previous Version | Text Only | Print | Product List | Glossary Off
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50

000
FXUS66 KPDT 181448 AAA
AFDPDT

Area Forecast Discussion...Updated
National Weather Service Pendleton OR
748 AM PDT Mon Mar 18 2024

Update...Upper level ridge will remain over the region through
Tuesday before beginning to break down on Wednesday. Just some minor
changes to todays highs and tonight`s low temperatures to be more in
line with observed temperatures over the past 24 hours. Also
adjusted sky condition to be clear versus mostly clear.

.SHORT TERM...
Today through Wednesday night...
The short term period starts with a large upper ridge over the
area, which will continue to bring dry weather and above normal
temperatures through Tuesday.

High temperatures ended up being a couple of degrees warmer than
forecast on Sunday, and with the ridge peaking over the region
today and Tuesday, expect it will be even warmer. Highs well into
the 70s are expected in many areas which will be 15 to 20 degrees
above normal.

The ECMWF EFI continues to show high temperature anomalies between
0.6 and 0.9 today across the entire area. These anomalies increase
to between 0.7 and 0.95 on Tuesday, with most of the region
between 0.8 and 0.9. Overall anomalies decrease a bit on
Wednesday, but most of the area is still in the 0.8 to 0.9 range.

The ridge will begin to be suppressed southward by Tuesday night
as an upper low/trough moves towards southern British
Columbia/Northwest Washington. This low will help flatten the
upper flow and it will become more zonal by later Wednesday into
Wednesday night.

The more zonal flow will allow for some precipitation to develop
over the Cascades beginning Wednesday, but more so into Wednesday
night, and some low chances (20-30%) of precipitation over the
Blue Mountains and Mountains of Wallow County by Wednesday night.
These chances will be the first precipitation chances of the week.

Additionally the westerly flow on Wednesday into Wednesday night
will yield a tightening pressure gradient and breezy conditions,
mainly across the Columbia Basin, Yakima and Kittitas Valleys and
nearby locations. Winds look to gust in the 25 to 35 mph range.

After peaking on Tuesday, high temperatures will decrease on
Wednesday, but will still remain above normal. High will generally
bey in the low to mid 60s. Overnight lows will tonight through
Tuesday night will generally be in the 40s, except in central
Oregon, where upper 30s are expected. Wednesday night will
generally be a few degrees cooler.


.LONG TERM...

Thursday through Monday...Models in good agreement with the
overall pattern, but continue to struggle with timing of upper
level trough moving onshore over the weekend. WPC cluster analysis
indicates weak ridging over the area Thursday ahead of a
deepening trough over the eastern Pacific. By Friday, 84 percent
of members show the upper level trough remaining off the coast.
For Saturday, 50 percent of members (cluster 1 and 4) show the
trough remaining off the coast while 50 percent (cluster 2 and 3)
show it moving onshore. By Sunday, only one cluster member
(cluster 1) shows the trough remaining offshore (barely). This
discrepancy in timing is depicted nicely in the EOFs which show a
42% variance for both Saturday and Sunday. Models continue to slow
the trough down with each new run, but confidence is moderate to
high (60-70%) they are beginning to settle on a solution so we
will see its impact on our area by the weekend. The ensembles are
in good agreement too with the ECMWF a little faster (6 hours) on
bringing the trough onshore Saturday. The deterministic models are
slightly faster but still in good agreement. By Monday, Northwest
flow develops behind the exiting trough resulting in mostly dry
conditions, except for the mountains. In summary, Thursday should
be mostly dry except the mountains with increasing chances of
widespread precipitation by the weekend and drier Monday.

The chance of seeing 0.10 inch of precipitation in 24 hours
increases to 50-70 percent over the mountains Friday with 50+%
values spreading throughout the CWA Saturday.  Values do decrease
for Sunday but the chance of seeing at least 0.01 of an inch remains
above 50 percent for much of the CWA. As a result, confidence is
moderate to high (70-80%) we`ll see a good wetting rain over the
weekend.

Daytime highs are expected to remain above normal Thursday and
Friday, but drop below normal through the rest of the period.
Earle/81

&&

.AVIATION...
12Z TAFS...VFR conditions will prevail through the period.  Patchy
cirrus is expected to drift across portions of the area today, but
otherwise, clear skies.  Winds will be 10 kts or less.  Earle/81

&&

.PRELIMINARY POINT TEMPS/POPS...
PDT  72  43  72  45 /   0   0   0   0
ALW  74  46  74  50 /   0   0   0   0
PSC  75  45  76  48 /   0   0   0   0
YKM  74  41  74  42 /   0   0   0   0
HRI  75  44  77  47 /   0   0   0   0
ELN  72  42  72  43 /   0   0   0   0
RDM  72  38  72  38 /   0   0   0   0
LGD  71  41  71  42 /   0   0   0   0
GCD  70  39  70  40 /   0   0   0   0
DLS  76  48  76  48 /   0   0   0   0

&&

.PDT WATCHES/WARNINGS/ADVISORIES...
OR...None.
WA...None.
&&

$$

SHORT TERM...77
LONG TERM....81
AVIATION...81


USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.