High Wind in Oregon, November 16 to 17, 2020

Area Forecast Discussion
National Weather Service Pendleton OR
843 PM PST Mon Nov 16 2020

.UPDATE...Significant cloud cover in areas have allowed for
temperatures to be slower to cool, so bumped up overnight low
temperatures a bit around the Dalles, Redmond, and Pendleton
areas. The warm front is continuing to crawl through our area from
south to north, and will keep tracking through Washington and into
British Columbia overnight. Winds have already begun to increase
at the base of the Blues, which will become more widespread as we
proceed through the night and into Tuesday morning. Windy
conditions will ensue through much of the day tomorrow, as the
associated cold front begins to drive through our area. A Wind
Advisory is currently active for the Grande Ronde Valley, with
Wind Advisories for Wallowa county and along the foothills of the
Blues beginning at 10 PM. 75

&&

.PREV DISCUSSION... /issued 339 PM PST Mon Nov 16 2020/

SHORT TERM...Today and Tuesday...Warm front lifting through the CWA
will bring showers through the WA Cascades and foothills until
early evening. Mild and cloudy conditions expected otherwise for
the rest of the area, with highs climbing into the low to mid 50s
for lower elevations as a warm and moist SW wind aloft keeps us
insulated through Tuesday, with overnight lows dropping off very
little from today's highs, especially in central OR and areas
around the Blue Mountains where winds will pick up substantially
overnight.

Trailing the warm front is a deepening surface low off the coast of
BC, leading to a tight pressure gradient spreading from the far
eastern OR valleys through coastal WA. This gradient favors a strong
south to southeast flow, particularly for central OR and the Grande
Ronde Valley, with downsloping winds for the Blue Mountains
impacting the southeastern and southern portions of the Columbia
Basin. This, combined with model forecast pressure gradient values
aligning with that of a strong wind event, have led to wind
advisories for the foothills of the Blue Mountains and the Grande
Ronde Valley, with gusts reaching and surpassing at times 50 mph.
Gusts are expected to be slightly lighter in central OR given a
weaker forecasted pressure gradient, but may need to roll these
areas into an advisory later this evening as well. Expect the
strongest winds to begin in Grande Ronde this evening, with the Blue
Mountains following a few hours after, continuing through Tuesday
evening. Central OR will see a later onset, closer to early Tuesday
morning. Important to note that this wind event within the Basin
will be isolated to areas right along the foothills of the Blues,
with a rapidly deteriorating effect on the winds more inland toward
the lower Basin, such as in Hermiston and Tri-Cities. Expect highs
tomorrow to reach close to 60, locally higher along the foothills,
while the lower Basin sees low to mid 50s. Central OR may see upper
50s given warm southerly downslope flow through the US-97
corridor.

LONG TERM...Wednesday through Monday. The weather pattern remains
active through the weekend and models are in fairly good
agreement. Westerly flow aloft. Upper level troughs will move
across the region every 24-36 hours with periods of rain and
mountain snow. Temperatures will be near seasonal averages with
highs in the 40s to lower 50s.

AVIATION...00Z TAFS...Ceilings and visibilities degrading quickly
for PDT and ALW as they are currently experiencing LIFR conditions.
PDT should improve shortly, but ALW may stay in LIFR/IFR until
around 07Z. IFR conditions currently for YKM and PSC, MVFR
conditions currently for DLS, and VFR for RDM and BDN. Winds should
stay below 10kt, but should pick up between 10 and 15 kt sustained
winds with gusts around 30kts for RDM/BDN/ALW. Southerly low level
wind shear will develop overnight for PDT/RDM/BDN/ALW at around 2kft
AGL at 30kts to 40kts. 75

&&

.PRELIMINARY POINT TEMPS/POPS...
PDT  44  61  40  53 /   0  10  30  50
ALW  43  59  42  54 /  10  10  50  50
PSC  39  57  42  54 /   0  10  20  20
YKM  35  51  33  49 /   0  30  30  40
HRI  39  57  41  54 /   0  10  30  30
ELN  36  48  32  45 /  10  30  30  40
RDM  45  58  35  48 /   0  30  30  50
LGD  40  51  37  47 /   0  10  50  60
GCD  41  57  37  47 /   0  10  50  60
DLS  44  55  41  50 /   0  40  40  60

&&

.PDT WATCHES/WARNINGS/ADVISORIES...
OR...Wind Advisory until 4 PM PST Tuesday for ORZ050-507-508-510.

     Wind Advisory until 4 PM PST Tuesday for ORZ049.

WA...Wind Advisory until 4 PM PST Tuesday for WAZ029.

&&

SHORT TERM...75
LONG TERM....75
AVIATION...75