Area Forecast Discussion
Issued by NWS Pendleton, OR

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FXUS66 KPDT 240258

Area Forecast Discussion
National Weather Service Pendleton OR
758 PM PDT SUN OCT 23 2016

.UPDATE...Mid to high level moisture continues to stream
northeastward over the forecast area this evening in a southwest
flow aloft. A weather disturbance and weak cold front will push into
western Oregon and Washington overnight bringing a few rain showers
to the Cascades, especially to the Washington Cascades by morning. A
deep upper low pressure system located about 300-400 miles off the
coast will move northward during the day Monday and will send a
stronger front and a push of deeper moisture into the Pacific
Northwest. However the precipitation on Monday will only make it as
far east as the east slopes of the Cascades as the flow becomes more
southerly, which will slow down the eastward progression of the
moisture. The moisture will continue to spread eastward Monday night
into Tuesday. There will be a better chance of rain over the CWA
Monday night and Tuesday as a result. Drying will take place over
western areas of the CWA Tuesday afternoon while showers continue
from the Blue Mountains and Elkhorn Mountains eastward. A southerly
flow on Monday will cause downslope winds off the Blue Mountains
onto the Foothills Monday causing warming temperatures there with
temperatures in the 60s to around 70. Elsewhere temperatures will be
cooler and in the 50s to mid 60s. Winds will increase over southern
areas of the forecast area and it will become breezy to windy there
by Monday afternoon as mixing allows stronger winds aloft to reach
the surface. At this time am not expecting wind advisory winds, but
it will need to be monitored for the possibility. These winds will
diminish Monday night. Additional weather systems are expected to
move across the region for most of the rest of the week as a moist
southwest flow aloft persists with an upper trough over the eastern
Pacific and an upper ridge over inland west. 88


.AVIATION...06Z TAFs...VFR conditions will persist overnight at all
TAF sites in the CWA. Mid and high clouds will prevent any fog from
forming. Winds will be light overnight in all areas. Then it will
become breezy to windy with wind speeds of 15 to 25 kts with higher
gusts possible at TAF sites KRDM and KBDN by 18Z Monday. Elsewhere
winds will remain fairly light through Monday evening. 88


.PREV DISCUSSION... /issued 233 PM PDT SUN OCT 23 2016/

SHORT TERM...Tonight through Tuesday night...An upper level low and
trough is located a few hundred miles off the Pacific Northwest
coast this afternoon with moisture streaming into the area on a
southwest flow aloft. This evening will be cloudy and dry but later
tonight the low will strengthen and swing closer to the coast. This
will turn the flow more southerly and and a front will begin to push
ashore. Light showers ahead of the front will bring a slight chance
of rain to the Cascades, especially in Washington. The low will make
slow progress eastward on Monday with showers as far east as
Ellensburg, Yakima and Bend in the afternoon. Breezy southerly winds
of 15 to 25 mph will pick up in the afternoon in the southern half
of the area and diminish in the evening. The front will continue
across the area Monday night with a chance of rain through the night
in the eastern half of the area and tapering off to a slight chance
in the west overnight. By Tuesday, the low and trough will have
moved north with the low off the British Columbia coast. A few weak
disturbances will move through the trough with a chance of rain over
the mountains while the lower elevations are dry. Tuesday night, the
low will reorganize off the Oregon coast and another front will
begin moving into the area from the southwest. Central Oregon and
the Ochoco-John Day Highlands will have a chance of rain in the
evening which will spread across the rest of the area overnight.
Temperatures on Monday will be a few degrees warmer due to the
southerly winds, especially in the Blue Mountain foothills which
will be around 70 while the rest of the area is in the upper 50s and
60s. Tuesday will see temperatures drop back to the mid 50s to mid
60s. Perry

LONG TERM...Wednesday through Sunday. Unsettled weather will
continue though the extended period.  A warm front will move north
across the region on Wednesday as a low pressure system moves north
along the coast.  The low will continue to move northeast into
Canada on Thursday with band of rain passing through the area.
Models are having problems with timing of next several weather
systems to move through Friday into Saturday and have kept a chance
of rain for most areas. It appears there will be a break between
systems late Saturday ahead of another system to move through
Sunday. Temperatures will be near to slightly above normal. 93


PDT  45  68  46  62 /   0  10  30  10
ALW  49  69  52  64 /   0  10  40  10
PSC  46  64  50  64 /   0  10  30  10
YKM  42  60  41  63 /  10  20  50  10
HRI  44  66  45  64 /  10  10  30  10
ELN  41  58  40  60 /  10  30  60  10
RDM  40  62  37  59 /  10  20  40  10
LGD  45  67  46  61 /   0  10  40  30
GCD  46  65  42  57 /  10  10  40  30
DLS  46  61  40  64 /  10  30  50  10


.PDT Watches/Warnings/Advisories...


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