754 
FXUS66 KPDT 111501
AFDPDT

Area Forecast Discussion
National Weather Service Pendleton OR
801 AM PDT Mon Sep 11 2023

.UPDATED...Continue to see a transition to a westerly flow as a weak 
upper level trough gains influence over the Pacific Northwest. This 
is allowing a little more cloudiness into the region today that will 
suppress temperatures resulting in cooler temperatures today. Will 
also see an uptick in winds along portions of the east slopes of the 
Cascades mainly through the Columbia Gorge and the Kittitas Valley. 
Minor changes made in the morning forecast to sky conditions, 
temperatures and winds.  

.SHORT TERM...Today through Wednesday night...Deterministic models
and ensembles remain in excellent agreement on the evolution of
the 500 mb pattern over the next few days which gives high
confidence in the forecast. A shortwave trough will move across 
WA today causing a weak marine push and breezy winds this 
afternoon and evening through the Columbia Gorge and Kittitas 
Valley. Winds in these locations will be 15 to 25 mph sustained 
with the ECMWF ensemble showing mean peak gusts around 30 mph 
this afternoon and evening. High temperatures today will be in the
low to mid 80s with 70s in the mountains. On Tuesday another 
stronger shortwave will begin to move across the area during the 
evening and clear the region Wednesday morning. This will result 
in a slightly stronger marine push Tuesday with winds of 18-30 mph 
and gusts to around 35 mph in the Cascade gaps. The probability of 
maximum sustained winds of 20 mph or greater Tuesday is 80% at KELN 
and 73% at KDLS. Where winds will be strongest Tuesday afternoon 
humidities will be 30-35%. Thus critical fire weather conditions are 
not expected at this time. On Tuesday night there will be a 20-40% 
chance of light showers along the Washington Cascade crest...mainly 
over northwestern Yakima and western Kittitas Counties otherwise it 
will be dry. Wednesday and Wednesday night a ridge of high pressure 
will build over the region from off the Pacific bringing continued 
dry conditions and near normal temperatures. 78

.LONG TERM...Thursday through Monday...Models remain in good 
agreement with the development of high pressure on Thursday. Dry 
conditions and warming temperatures will result from this pattern, 
with the area of high pressure remaining through Sunday/Monday. 
Temperatures through the period will reach 10 to 15 degrees above 
normal, with the warmest temperatures expected Saturday and Sunday 
for much of the area. Sunday will see a swath of moderate confidence 
(60-70%) in temperatures around 90 degrees across the Columbia 
Basin, especially across the Tri-Cities and areas north. 

An approaching system late Sunday and into Monday will push the warm 
and dry conditions further east, with a slight chance (15-30%) of 
showers developing across the Oregon and Washington Cascades. 
Temperatures will see a dip of around 5 degrees from this system on 
Monday, though still remain around 5 to 10 degrees above normal. 
Branham/76

&&

.AVIATION...12z TAFs...VFR conditions continue with dry conditions
today. Increased mid-high level clouds favored today, with a line
of clouds traveling from west to east through the day. An uptick
in wind speed expected for much of the region, with the strongest
wind favored near the Oregon/Washington border with a 60-70% 
chance for winds of at least 25 mph. Branham/76

&&

.PRELIMINARY POINT TEMPS/POPS...
PDT  83  53  79  54 /   0   0   0   0 
ALW  85  58  81  56 /   0   0   0   0 
PSC  87  60  84  58 /   0   0   0   0 
YKM  84  52  82  51 /   0   0   0   0 
HRI  87  59  84  57 /   0   0   0   0 
ELN  80  54  80  54 /   0   0   0   0 
RDM  81  47  78  45 /   0   0   0   0 
LGD  84  52  79  50 /   0   0   0   0 
GCD  87  50  82  48 /   0   0   0   0 
DLS  81  58  81  59 /   0   0   0   0 

&&

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

$$

SHORT TERM...78
LONG TERM....76
AVIATION...76