Area Forecast Discussion
Issued by NWS Pendleton, OR

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FXUS66 KPDT 240543 AAA
AFDPDT

Area Forecast Discussion...Update
National Weather Service Pendleton OR
1043 PM PDT Thu Mar 23 2017

Updated Aviation Discussion

.SHORT TERM...Evening update...The next Pacific system continues
move into the Pacific Northwest this evening. Precip has largely
overspread the portions of Oregon and Washington west of the
Cascades. This precip is now beginning to spread into central Oregon
and Washington. Expect this precip to move into eastern Oregon and
washington later this evening and overnight. The cold front with
this system will move across the region Friday, exiting the area by
mid afternoon. Steady precip will continue ahead of and with this
front. Precip over our central Oregon and Washington zones should
become showery by afternoon Friday. Winds will be locally breezy,
mainly in the Grande Ronde Valley and over the mountains. Snow
levels will run around 2700 feet over Kittitas county tonight to
between 4000 and 5200 feet elsewhere. On Friday snow levels will
rise some over south-central and central Washington, but fall a bit
over central Oregon. Overall, snow levels across the area by Friday
afternoon will run between 4200 and 5200 feet. Heaviest snow fall
will be above 5000 feet late tonight through Friday, and will total
6 inches or less. Rainfall will be locally heavy, so some rises on
small streams can be expected. The current forecast package covers
much of these trends and updates were focused on adjustments to snow
levels, precip amounts and timing of precip. 90

.LONG TERM...Previous Discussion...Two major weather systems will
impact the forecast area during the extended. The first will arrive
on Sunday and linger into Monday. This system comes off the Pacific
Ocean in a westerly flow as an upper level trough but then develops
a closed low that dives into California and eventually the Desert
Southwest. This will weaken the system as it moves inland but still
the system will spread precipitation across the forecast area with
snow levels 3500 to 5000 feet.

The next system arrives on Wednesday as another upper level trough
pushes a cold front through the region. Snow levels will begin
around 5000 feet and then lower to around 4000 feet on Thursday as
precipitation turns to showers and decreases.

&&

.AVIATION...06Z TAFs...VFR conditions are expected during the next
24 hours. The next Pacific system will spread periods of rain or
rain showers across the area through a good portion of this period.
This precip should begin at all sites withing the first 3 hours of
the period. Generally expect cigs/vis to remain VFR but brief
periods of MVFR in lower CIGS may be possible due to persistent
rainfall. For now will hint at this potential with SCT clouds below
3000 ft AGL at some sites. Winds will mainly run 5 to 15 kts through
the period. 90

&&

.PRELIMINARY POINT TEMPS/POPS...
PDT  39  53  39  54 /  60  90  40  20
ALW  43  53  42  56 /  50  90  40  30
PSC  42  55  41  59 /  50  90  10  10
YKM  41  57  36  59 /  60  70  10  10
HRI  40  55  40  57 /  50  90  10  10
ELN  38  50  33  52 /  70  70  10  10
RDM  38  54  33  52 /  60  60  10  10
LGD  38  52  37  54 /  40  80  60  40
GCD  39  52  35  54 /  50  90  50  40
DLS  44  55  41  57 /  70  80  10  20

&&

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

$$

90/91/90


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