Area Forecast Discussion

FXUS66 KPDT 201745 AAA
Area Forecast Discussion...Updated
National Weather Service Pendleton OR
1045 AM PDT Tue Mar 20 2018
Updated AVIATION discussion
.SHORT TERM...Today and tonight...Remnants of a weak disturbance 
moving through central Oregon overnight will be exiting Grant county 
this morning with just some lingering snow showers over the 
mountains through this morning. Otherwise, skies will be mostly 
sunny today with mild temperatures and light winds. A low pressure 
system off the coast of California will begin to spread moisture 
over the region tonight in an increasing southwest flow. This will 
lead to some light precipitation developing over the southern 
portion of the forecast area with snow levels around 4000 to 5000 
feet resulting in some minor accumulations.
.AVIATION...18Z TAFs...VFR conditions for the next 24 hours. Mostly 
clear today with winds 5-10kt. Increasing clouds this evening at 
KRDM and KBDN spreading over these TAF sites from the southwest with 
ceilings becoming 050-100. Lowering cloud bases spread northeast to 
other TAF sites overnight. Some light rain possible at KRDM, KBDN, 
and KDLS beginning around 12Z. Onset of precipitation at other TAF 
sites will be possible Wednesday afternoon. Winds overnight 5-10kt 
becoming 5-15kt by late morning.  Polan
.PREVIOUS DISCUSSION... /issued 210 AM PDT Tue Mar 20 2018/ 
SHORT TERM...Today through Thursday afternoon...The small weak upper 
level low off the Oregon coast is shearing apart and will move inland 
across OR as a weak wave this morning. It might produce some some 
clouds and light precipitation from Central OR eastward. Snow levels 
will be around 1500-4000 feet this morning. Southwest flow aloft 
will begin to increase tonight and Wednesday as a stronger upper 
level trough develops offshore. The southwest flow will advect 
warmer air and moisture from a low pressure system off the 
California coast into OR and WA Wednesday and Thursday. A warm front 
will spread precipitation north across OR and WA Wednesday. Snow 
levels will increase to 2500-5000 feet Wednesday morning to 5000-
7000 feet Wednesday evening. There will be locally breezy southerly 
winds across central OR and the Ochoco John Day Highlands Wednesday 
night and Thursday as higher winds aloft mix to the surface. A cold 
front will move into eastern WA and OR Thursday afternoon. Winds 
will switch to westerly behind the front with breezy/windy 
conditions over most of the CWA.  Coonfield 
LONG TERM...Thursday night through Monday. Fairly active pattern
for the region as several systems move across the Pacific northwest.
A strong cold front will be exiting the region Thursday night as an 
upper low approaches the coast. Steady precipitation will taper off 
overnight. Friday through the weekend and into early next week 
several upper level troughs will move through the forecast area in 
the northwest flow aloft. GFS and Euro are in reasonable agreement 
with the overall pattern. These will result in periods of rain and 
mid-higher elevation snow. After the cold frontal passage Thu night 
snow levels will fall into the 2000-4000 foot range through the 
weekend with a cooler airmass over the region. High temperatures 
will be in the 40s to lower 50s. Lows in the 20s and 30s. Occasional 
breezy southwesterly winds expected. 94
PDT  59  36  62  45 /   0  10  20  40 
ALW  59  36  61  47 /   0  10  20  30 
PSC  63  34  63  46 /   0   0  20  40 
YKM  61  32  60  42 /   0   0  20  70 
HRI  61  35  63  45 /   0  10  20  50 
ELN  58  31  55  38 /   0   0  20  60 
RDM  56  33  57  38 /   0  20  50  60 
LGD  52  37  55  43 /  10  20  30  40 
GCD  54  37  57  44 /  10  20  50  50 
DLS  63  39  61  42 /   0  10  30  70