Area Forecast Discussion
Issued by NWS Pendleton, OR

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FXUS66 KPDT 260256
AFDPDT

Area Forecast Discussion
National Weather Service Pendleton OR
756 PM PDT Tue Sep 25 2018

.SHORT TERM...Tonight and Wednesday...Just made some minor changes
to temperatures and winds for overnight and Wednesday in a forecast
update. A ridge of high pressure off the coast will keep the
forecast area under a dry and stable northwest flow. Temperatures
will be 3 to 10 degrees warmer Wednesday with winds remaining light.



&&

.PREV DISCUSSION... /issued 201 PM PDT Tue Sep 25 2018/

SHORT TERM...Tonight through Friday...A blocking ridge will
persist offshore through the short term period. This will produce
stable dry northwest flow with light mainly diurnal winds. Some
thin CI may move through at times but skies will be mostly clear.
Radiational cooling at night will be strong due to clear skies,
light winds, and lengthening nights. Surface inversions will
become shallower tonight as the ridge builds toward the coast.
Low temperatures will warm up Wednesday and Thursday morning with
the strongest increases on ridge tops because the ridges are above
the shallow inversions. Days will be sunny and warm after the
morning inversions break. High temperatures will increase
Wednesday and Thursday into the 70s and low 80s due to building
ridge...then decrease Friday as a weak trough moves into MT and
the ridge retrogrades in the eastern Pacific. Coonfield

LONG TERM...Friday night through Tuesday...Models in good
agreement through the weekend with closed low of the rex block
beginning to work ashore the northern CA/souther OR border on
Saturday. Southwesterly flow ahead of the low will bring in moisture
and weak instability into the region later Saturday afternoon and
evening. Expect in increase in cloudiness and a chance of showers
across the Cascades and into the Blues and Wallowas. Ever so slight
chance of a lightning strike or two, but with limited extent of
moisture and instability have kept out mention of thunder for now.
Sunday as the low shifts east, moisture and instability increase
across the region and have a chance of showers across the CWA with a
slight chance for thunderstorms over the Oregon zones, especially
over the Blues and Wallowas. Model differentiate next week but
general trend is for another low to approach the west coast and a
trough swinging down south out of Canada. Leaned towards the
ensemble mean for pops and expect a chance of showers mostly focused
in the higher terrain on Monday and Tuesday. After another warm day
on Saturday with highs in the 70s, slightly cooler temps expected
Sunday through Tuesday with the unsettled pattern. Highs expected in
the 60s to low 70s. Nighttime lows will be moderated a bit near 40
to low 50s due to the increased cloud cover.

AVIATION...00z TAFS...VFR conditions with a few high cirrus through
the period and light winds generally less than 8KTs.

&&

.PRELIMINARY POINT TEMPS/POPS...
PDT  43  79  43  81 /   0   0   0   0
ALW  43  80  46  82 /   0   0   0   0
PSC  43  80  43  82 /   0   0   0   0
YKM  40  80  44  82 /   0   0   0   0
HRI  41  81  43  83 /   0   0   0   0
ELN  40  81  43  80 /   0   0   0   0
RDM  31  83  36  86 /   0   0   0   0
LGD  36  78  38  80 /   0   0   0   0
GCD  41  79  42  84 /   0   0   0   0
DLS  43  84  46  86 /   0   0   0   0

&&

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

$$

91/91/91



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