Area Forecast Discussion
Issued by NWS Pendleton, OR

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FXUS66 KPDT 161615
AFDPDT

Area Forecast Discussion
National Weather Service Pendleton OR
915 AM PDT Sat Mar 16 2024

.UPDATE...Current radar and visible satellite imagery showing dry
conditions as a light veil of high level cirrus clouds stream in
from the north. This is in response to an area of strong high
pressure currently located across the Pacific Northwest and
extending north into Central British Columbia, which will persist
through the weekend. High temperatures will again breach into the
mid to upper 60s through the Basin, Eastern Gorge, Central
Oregon, and the Yakima/Kittitas Valleys under light winds
primarily out of the north-northeast. These high temperatures are
about 6 to 12 degrees above normal. Clear skies will extend into
tonight to again attribute to a quick cool down after sunset, but
low temperatures Sunday morning will be 2 to 6 degrees warmer
than Saturday morning.

Minor edits were conducted to temperatures, sky cover, relative
humidity, and winds to better account for current observations and
recent guidance. 75


&&

.PREV DISCUSSION... /issued 327 AM PDT Sat Mar 16 2024/

SHORT TERM...
Today through Monday night...High pressure was located over the
PAcific Northwest. This high will continue to build through the
weekend into early next week and bring dry weather and unseasonably
warm temperatures. High temperatures will rise each day through
the weekend and into early next week. High temperatures will
average about 10 degrees above normal by Monday.

Confidence remains high (90-100%) in the above normal
temperatures. The ECMWF EFI begins to support the anomalous highs
beginning today with values ranging from 0.5 to 0.8 across
portions of the area. However, the support increases SUnday and
especially Monday. By Monday virtually the entire state of
Washington is covered in 0.7 to 0.8 reading or higher and most of
our area in Oregon is in 0.7 to 0.8 or higher as well on the ECMWF
EFI.

High temperatures today will mainly be in the low to mid 60s. On
Sunday, highs will be in the mid to upper 60s, with a few locations
in the Columbia Basin possibly reaching 70 degrees. However, only
a few ensemble members in the GFS and ECMWF actually hit 70 degrees.
On Monday, highs across the area are in the lower 70s in many
locations. The ECMWF ensemble members are more supportive of 70+
than the GFS with 50% or more members of the ECMWF generally >= 70
degrees, while the GFS has far fewer, depending on location.

Overnight lows will be warming each day as well and will mainly be
in the 30s and 40s.  Winds are expected to be light.

LONG TERM...
Tuesday through Saturday...Models in pretty good agreement
Tuesday in weakening the upper level ridge as it is pushed
southeastward as the next trough digs southwestward from BC into
the eastern Pacific. Wednesday and beyond models begin to struggle
on the evolution of the aforementioned trough. This is reflected
nicely in the WPC cluster analysis. 68% of the members show this
trough off the coast producing general southwest flow aloft for
Wednesday while 32% of the members show a more zonal pattern. By
Thursday its approximately 50:50 on southwest flow (trough off the
coast) or zonal flow. Friday and Saturday the discrepancies
continue with 50% showing the upper tough remaining off the coast
while Cluster 1 (31% of members) shows a trough over the area. At
this time, the mean ensembles generally show the trough remaining
off the coast through Friday bringing it onshore late Saturday and
weakening it as it moves inland. It appears the greatest chance
for widespread precipitation will be Friday and Saturday as the
upper trough inches closer and then pushes through the area
Saturday night. 24hr QPF is expected to remain generally light
with probability of exceeding 0.10 inch is 40-55% over the
Cascades Wednesday and 20-30% over the Blue Mountains. These
values rise to 60-70% over the Cascades and 40- 50% over the Blues
Thursday. Probabilities of exceeding 0.25 inches in 24 hours
remains 25% or less over the our mountains until Thursday when it
creeps up to 30-40% over the Blues with higher amounts over the
Cascade crest.

Tuesday will be the last day this week we see daytime highs 10-15
degrees above normal. Temperatures will drop 10 degrees or more
Wednesday and be near to slightly below average for the remainder of
the extended period.  Earle/81

AVIATION...
12Z TAFS...VFR conditions will prevail through the period. Some
patchy thin cirrus is expected to move through the area, especially
northern TAF sites. Otherwise, clear skies are expected. Winds will
be 10 kts or less. Earle/81

&&

.PRELIMINARY POINT TEMPS/POPS...
PDT  63  39  66  41 /   0   0   0   0
ALW  65  42  67  44 /   0   0   0   0
PSC  67  41  69  43 /   0   0   0   0
YKM  68  39  71  40 /   0   0   0   0
HRI  67  39  69  42 /   0   0   0   0
ELN  66  40  69  42 /   0   0   0   0
RDM  65  31  65  34 /   0   0   0   0
LGD  66  37  66  39 /   0   0   0   0
GCD  66  36  67  36 /   0   0   0   0
DLS  69  43  71  44 /   0   0   0   0

&&

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

$$

UPDATE...75
SHORT TERM...77
LONG TERM....81
AVIATION...81


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