300 
FXUS66 KPDT 200901
AFDPDT

Area Forecast Discussion
National Weather Service Pendleton OR
201 AM PDT Mon May 20 2019

.SHORT TERM...Today through Wednesday...An upper level low pressure 
over the Great Basin this morning continues to wrap moisture back 
into eastern Oregon. There will be some lingering showers from 
northeast Oregon back into central Oregon due to this moisture today 
as well as along the crest of the Cascades. The next weather system 
is approaching the Pacific Northwest coast today and will move 
across southwest oregon tonight and into the Great Basin on Tuesday. 
This system will be a similar repeat of the past couple of systems 
which wraps some moisture around the north side of the low center as 
it passes to our south. This moisture will again mainly impact the 
central and northeast parts of Oregon with some rainfall totals of 
between half and inch and an inch overnight and Tuesday. The low 
will continue to spin over the Great basin Tuesday night and 
Wednesday with some moisture wrapping back into eastern oregon for 
some lingering showers. 

.LONG TERM...Wednesday night through next Tuesday...The forecast 
area will remain under an unsettled weather pattern through the 
extended period, occasionally interrupted by weak upper ridges. On 
Wednesday night and Thursday there will be an upper low over the 
Great Basin and a large upper ridge off the coast. In between these 
features will be a northeast wrap around flow over the forecast 
area...around the circulation of the Great Basin upper low. There 
will be a feed of moisture in this flow for showers over the CWA, 
especially over eastern area and along the Cascade east slopes. The 
ridge off the coast will begin to move into the coast by Friday 
morning which will bring some drying to the CWA for Friday morning. 
Then the long range models diverge quite a bit between the GFS and 
the other long range models. The GFS brings down another closed low 
from the north which would bring more showers and possible afternoon 
thunderstorms on Friday afternoon through Saturday. However, the 
other models (e.g. ECMWF and Canadian) keep a drier pattern with a 
mostly northerly flow over the CWA. Per consensus with surrounding 
offices, will not change the forecast for Friday afternoon through 
Saturday too much due to this uncertainty in the models. Then by 
Saturday night into Sunday night the other models do eventually 
bring down a closed upper low from the north too, and have more 
showers in the forecast for Sunday (mostly in eastern areas of the 
CWA) as a result. This upper low will take a track to the southeast 
into northern California with more wrap around moisture into 
northeast Oregon and SE Washington. The upper low then stalls and 
sits over the Great Basin on Monday and then moves off to the east 
on Tuesday with a drying and warming trend behind it for Monday 
night into Tuesday. Winds remain mostly light through the extended 
period, with some increase with passing weather systems, but nothing 
significant. Temperatures remain near to slightly below normal 
through Saturday and then a warming trend takes place Sunday through 
Tuesday with temperatures rising into the 80s in the lower 
elevations and 60s to lower 70s mountains. 88


&&

.AVIATION...12Z TAFs...VFR conditions will prevail for today with 
some scattered showers mainly south. However visibilities and CIGs 
will remain high enough for conditions to remain VFR. Then another 
weather system moves into the area tonight with increasing chances 
of rain showers. There may even be a slight chance of afternoon 
thunderstorms today over central Oregon and Wallowa County. The 
combination of rain and possible thunderstorms may cause conditions 
to briefly drop to MVFR at times from this afternoon through 
tonight. However, most of the time it will remain VFR. Winds will be 
light, except for some increase to 10 to 20 KTs near the eastern 
Columbia River Gorge this afternoon and this evening. Then the winds 
become light again after dark tonight in all areas. 88


&&

.PRELIMINARY POINT TEMPS/POPS...
PDT  67  46  63  46 /   0  50  60  10 
ALW  69  48  66  48 /   0  50  70  20 
PSC  74  52  71  53 /   0  20  40  10 
YKM  68  49  71  50 /  20  40  40  10 
HRI  71  49  69  49 /   0  40  40  10 
ELN  64  46  66  47 /  20  40  40  10 
RDM  59  38  59  39 /  40  60  40  30 
LGD  62  42  56  44 /  10  80  80  30 
GCD  59  41  53  44 /  20  80  60  30 
DLS  66  48  68  50 /  20  50  30  10 

&&

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

$$

91/88/88