Area Forecast Discussion
Issued by NWS Pendleton, OR

Home | Current Version | Previous Version | Text Only | Print | Product List | Glossary On
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
FXUS66 KPDT 171538

Area Forecast Discussion
National Weather Service Pendleton OR
837 AM PDT Sat Mar 17 2018

.SHORT TERM...Today and tonight...A large upper level low continues
to slowly track through southern Oregon and will be moving into
Idaho by this evening and overnight. Moisture wrapping around the
low is impacting most of the forecast area this morning with some
rain and snow showers. As the heating of the day progresses we will
see more instability showers developing. Showers will begin to
decrease after sunset for most of the forecast area but wrap around
moisture will continue over northeast Oregon and especially Wallowa
county. The winter weather advisory for wallowa county has been
extended through the night.


.PREV DISCUSSION... /issued 415 AM PDT Sat Mar 17 2018/

SHORT TERM...Today through Monday...A large upper low pressure
system continues to spin over southwest Oregon this morning. Wrap
around moisture from this low is pushing rain and mountain snow
showers over mainly Oregon, but there are some showers too in
Washington. The greatest chance of accumulating snow is over the
south central and the northeast portion of the forecast area, i.e.
the John Day Highlands, the John Day Basin and also Wallowa County
where there are currently Winter Weather Advisories in effect today
through noon for the John Day Basin and through 4 PM (23Z) over the
John Day Highlands and Wallowa County. Snow amounts will just be
enough to warrant these advisories. Elsewhere there will be rain and
mountain snow showers. The upper low will weaken as it tracks to the
east across southern Oregon today. Precipitation will gradually
taper off tonight through Sunday night with areal coverage of
showers will be decreasing. By Monday morning most areas will be dry
except the areas along the Idaho border, and the portion of the CWA
that borders MFR`s area of responsibility (south central Oregon).
There may also be some lingering showers over the northern Blue
Mountains as well as the Cascade east slopes. Then another upper low
will track southward along the Oregon/Washington coast by late
Monday, which will bring another chance of rain and mountain snow
showers to southern portions of the CWA as well as the Cascade east
slopes and the Blue Mountains by Monday evening. There will be a
slow warming trend through the short term, however by only a couple
degrees each day. However, it will remain cooler than normal for mid
March with temperatures in the 50s in the lower elevations and 30s
to 40s over the mountains. Winds will be light throughout the short
term forecast period. 88

LONG TERM...Monday Night Through Friday...A series of upper level
troughs will move through WA and OR during the extended time period.
An upper level low and associated trough will move across OR with a
few showers Monday night and Tuesday. Another trough will move
toward the coast Tuesday night with rain and high elevation snow
moving into eastern WA and OR. Snow levels Tuesday night and
Wednesday will be 4000-5000 feet. This system will bring increasing
PoPs Wednesday with rain and snow. Snow levels rise to 6000 feet
Wednesday night due to broad southerly flow ahead of another trough
approaching the coast. This trough will move slowly across WA and OR
Thursday and Friday with rain and snow likely. Snow levels will
start mainly above 5000 feet Thursday then decrease to 1000-1500
feet Friday. Coonfield

AVIATION...12Z TAFs...A broad upper level low will keep conditions
moist and unstable through 03-06Z. Areas of rain and/or snow showers
move either near or over most TAF sites at some point today. Best
chances of showers will occur during the morning and early afternoon
hours at KRDM, KBDN, KALW and KPDT. Shower chances will be more
limited at KDLS KPSC and KYKM. Cigs/vis will mainly be VFR. MVFR
conditions will be possible at KALW KPDT KRDM and KBDN due to
upslope flow and the shower activity. Winds will generally be 5 to
15 kts through the period, though KDLS may have winds of 15 to 20
kts Saturday afternoon. 76


PDT  49  35  50  33 /  60  40  10  10
ALW  50  37  51  33 /  60  40  10  10
PSC  55  36  56  32 /  30  20  10   0
YKM  56  34  55  31 /  20  20  10  10
HRI  53  36  54  33 /  30  20  10   0
ELN  53  33  51  30 /  20  20  10  10
RDM  46  26  46  24 /  60  30  10  10
LGD  42  32  43  28 /  70  70  20  10
GCD  41  31  42  29 /  60  50  10  10
DLS  54  38  54  34 /  20  20  10  10


OR...Winter Weather Advisory until 8 AM PDT Sunday for ORZ050.



91/83/83 is the U.S. government's official web portal to all federal, state and local government web resources and services.