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Area Forecast Discussion (AFD)

Issued by Pendleton, OR (PDT)

FXUS66 KPDT 201541

Area Forecast Discussion
National Weather Service Pendleton OR
841 AM PDT Wed Mar 20 2019

.SHORT TERM...Upper low moving into California spreading clouds
into southern and central Oregon this morning. This will continue
through the day into tonight. Further to the north sunny skies 
with temps into the upper 50s and lower 60s. Models indicate a 
deeper plume of moisture rotating into central Oregon this evening
and overnight with rain likely. 94


.PREV DISCUSSION... /issued 259 AM PDT Wed Mar 20 2019/ 

SHORT TERM...Today through Friday night...Water vapor imagery 
shows a very impressive upper ridge centered over the high plains 
of North America. A strong upper trough is currently moving into 
california...with limited moisture on the periphery spreading 
northward into southern Oregon. Impacts with the California system
will be minimal with just a little light rain possible mainly in 
Deschutes County today into Thursday. A more northern track 
system will impact the region late Friday and Friday night with 
mostly rain and some high mountain snow above about 4500 feet. 
This system will weaken as it encounters the ridge so QPF amounts 
will be fairly light. Thus not expecting major snow accumulations
through Friday night. Temperatures are starting to warmup in the 
lower elevations now that the snowpack is dwindling and the 
blended temperature guidance is running a bit cool. Have nudged 
temperatures toward the GFS MOS which is on the warmer side of the
envelope of available guidance. Depending on cloud cover...high 
temperatures could be in the low to mid 60s across the Columbia 
Basin and adjacent valleys the next few days. With temperatures 
not as cool at night...creeks and streams will continue to run 
high with what's left of the snow continuing to melt. 78

LONG TERM...Saturday through Wednesday...A front will be exiting 
the area Saturday with a trough following behind into the area. 
Saturday will see a chance of rain with snow above 4000 feet in the 
mountains and a slight chance of rain in the lower elevations. The 
system will depart Saturday evening with a chance of rain and snow 
in the Cascades and eastern Oregon mountains while the rest of the 
area dries out. Precipitation amounts will be under a tenth of an 
inch of rain or an inch of snow. Sunday and Sunday night will see 
some weak ridging and will be a break between systems with fair 
weather. On Monday, a strong upper low will arrive near the coast 
and drive a front northward from Oregon into British Columbia Monday 
and Monday night. Impacts will be felt mainly over the western 
portion of the area with a chance of rain with snow above 4500 feet 
while the eastern Columbia Basin from the Tri-Cities and Hermiston 
and the northern Blue Mountains eastward will just see a slight 
chance of rain and mountain snow on Monday night. The low will 
remain off the Oregon/northern California coast through Tuesday with 
another batch of rain and high elevation snow moving through the 
area. The entire area will have a chance of rain with snow above 
5000 feet Monday through Tuesday. Temperatures Saturday through 
Tuesday will be near normal with highs in the mid 50s to lower 60s 
in the lower elevations and in the mid 40s to mid 50s in the 
mountains. Wednesday will be several degrees cooler with highs in 
the mid 40s to mid 50s. Perry

AVIATION...12Z TAFS...VFR conditions will prevail through the
forecast period. Mid and high clouds will increase from sw to ne
today and tonight. Ceilings may lower to 7 or 8 thousand feet AGL
at KBDN and KRDM where a little light rain could occur. Some 
patchy BR is possible for a couple of hours around sunrise this 
morning. Winds will be mostly 10 kt or less. 78


PDT  60  36  57  39 /   0  10   0  10 
ALW  63  39  59  42 /   0  10   0   0 
PSC  62  38  61  41 /   0  10   0  10 
YKM  62  37  64  38 /   0  10   0  10 
HRI  64  39  62  41 /   0  10   0   0 
ELN  61  34  62  36 /   0  10   0  10 
RDM  52  34  51  32 /  10  40  30  20 
LGD  61  34  60  36 /   0  10   0  10 
GCD  59  36  57  37 /   0  20  10  10 
DLS  61  41  61  41 /   0  10  10  10