Area Forecast Discussion
Issued by NWS Pendleton, OR

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FXUS66 KPDT 250441

Area Forecast Discussion
National Weather Service Pendleton OR
841 PM PST Mon Feb 24 2020

.UPDATE...A quiet night is underway as high pressure centered
offshore builds over the area. Skies are mainly mostly clear to
partly cloudy though some higher clouds are developing along the
Oregon Cascades and giving north central and central Oregon
mostly cloudy skies. Have made some sky cover adjustments to match
current trends. Did make some minor adjustments to overnight lows
as well as increased higher cloudiness will have some ability to
keep temperatures up a bit. Winds have dropped off as expected and
the wind advisory in the Kittitas Valley was expired earlier.
Made some minor wind adjustments as well. Rest of the forecast was
in good shape and left it as is. Forecast update already out.


.PREV DISCUSSION... /issued 204 PM PST Mon Feb 24 2020/

SHORT TERM...Tonight through Wednesday night. Region currently
under northwest flow which has produced very light showers in the
WA Cascades, a deck of high level clouds over the eastern half of
the forecast area, and stratus over NE Oregon. Clearing over the
Kittitas valley has allowed for winds aloft to mix down, bringing
lower end advisory level winds this afternoon. A wind advisory was
issued for the Kittitas valley, and will last into the early
evening as winds will diminish with the day. A ridge over the
Pacific will move inland starting this evening into Tuesday
morning. This ridge will be flattened quickly by a weak upper
level shortwave traveling in the flow Tuesday evening. As the
shortwave travels over the forecast area Tuesday evening/night,
light snow showers in the WA Cascades and the OR/WA Blue mountains
are possible, however, this system will produce very little
precip in our forecast area. Behind the shortwave, ridge will
begin to strengthen and build back over a good portion of the
western CONUS. General ridging pattern will keep forecast area dry
with the start of a slow warming trend. Lawhorn/82

LONG TERM...Thursday into Friday...Generally quiet conditions
continue on Thursday and into Friday as modest ridging controls
the regions weather. High temps will be in the low 60s in the
Basin, a few degrees above normal. Based on model guidance and
the general pattern, Thu night into Fri AM may hold some fog
potential for the Columbia Basin, particularly around the river
and other areas of water, but devil is usually in the details with
regard to fog, and confidence is low. Actually, pattern most of
the week (with exception of weak system Tue-Wed) looks decent for
fog potential with downward atmospheric motion, weak ridging, and
light winds, but it will be a struggle to saturate the surface
layer each evening with a generally dry airmass in place.

Friday through Tuesday...The region`s weekend appears it will be
impacted by another moderately intense storm system. A shortwave
will drop south out of the Gulf of Alaska with another 995-1000mb
low forecast N of Vancouver Island. Though there are plenty of
differences, there are certainly commonalities between this past
weekend`s storm and the appearance on the synoptic level for next
weekend`s storm. It`s a bit early to discuss details but storm is
currently advertised to begin with snow in the WA Cascades and
breezy S winds in the Grande Ronde Valley Friday evening/night.
Cold front and associated westerly winds currently expected early
Saturday morning with breezy to windy conditions overspreading
broadly over Columbia Basin and Central Oregon. Rain and snow
showers will be likely over the Blue mountains much of the day
Saturday but system is advertised to move at a decent pace so high
end snow totals not currently expected for either Blue Mountains
or Cascades. System exits by Sunday morning with POPs tapering
off. Model agreement becomes a bit poor after this system, but
expecting ridging to return early next week with generally quiet
weather. clark/76

AVIATION...00Z TAFs...VFR conditions to continue through the
evening and overnight. Winds remain elevated in the Kittitas
valley and are still briefly breezy in other corners of the
region. These will ease as daylight (and mixing from aloft)
decreases through the evening. FEW to SCT high cirrus may persist
through the evening. clark/76


PDT  28  52  35  56 /   0   0   0  10
ALW  30  52  35  56 /   0   0   0  10
PSC  28  52  33  58 /   0   0   0   0
YKM  25  50  29  58 /   0   0   0   0
HRI  27  53  34  58 /   0   0   0   0
ELN  25  46  32  52 /   0   0  10   0
RDM  20  57  29  59 /   0   0   0   0
LGD  24  45  32  49 /   0   0   0  10
GCD  24  49  31  53 /   0   0   0   0
DLS  31  52  38  60 /   0   0   0   0




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