963
FXUS66 KPDT 272109
AFDPDT
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PENDLETON OR
209 PM PDT SAT JUN 27 2026
KEY MESSAGES
- ISOLATED THUNDERSTORMS ALONG OREGON CASCADES AND EASTERN
MOUNTAINS THIS AFTERNOON
- GUSTY WINDS DEVELOPING IN THE KITTITAS VALLEY SUNDAY AFTERNOON
- BELOW-NORMAL TEMPERATURES, BREEZY TO LOCALLY GUSTY WEST
WINDS, AND OCCASIONAL MOUNTAIN SHOWERS THROUGH THE WEEK
DISCUSSION
WATER VAPOR SATELLITE IMAGERY THIS AFTERNOON SHOWS
THE CENTER OF AN UPPER LOW HAS COME ONSHORE, THOUGH REGIONAL RADAR
IMAGERY SO FAR TODAY HAS SHOWN SHOWER ACTIVITY HAS MOSTLY BEEN
FOCUSED OUTSIDE OF THE FORECAST AREA. SHOWER ACTIVITY ACROSS
THE CASCADE CREST/EAST SLOPES AND ACROSS THE EASTERN MOUNTAINS
WILL DEVELOP OVER THE NEXT COUPLE HOURS AS THE LOW CONTINUES TO
PUSH INLAND. INCREASING SURFACE INSTABILITY AND MODEST LOW TO
MID LEVEL LAPSE RATES WILL ALSO ALLOW FOR A FEW SHOWERS TO
DEVELOP INTO ISOLATED THUNDERSTORMS THROUGH THIS EVENING.
OTHERWISE, BREEZY WEST TO NORTHWEST WINDS HAVE DEVELOPED THROUGH
THE CASCADE GAPS INTO THE COLUMBIA BASIN TODAY.
THE UPPER CLOSED LOW PUSHING INTO THE PACNW TODAY WILL START THE
PROLONGED TREND OF UPPER LEVEL TROUGHING OVER THE PACNW THROUGH
MOST THE NEXT WEEK. THE UPPER LOW WILL TRACK EAST ACROSS THE
REGION THROUGH MONDAY, WITH THE MAIN SHOWER ACTIVITY TIED TO A
SERIES OF SHORTWAVES ROUNDING THE LOW BOTH DAYS. THAT SAID,
SHOWER ACTIVITY WILL MAINLY BE CONFINED TO PORTIONS OF THE
CASCADES, NORTHERN BLUES, AND WALLOWAS THROUGH THIS PERIOD, WITH
BEST CHANCES OVER THE WALLOWA MOUNTAINS. CLUSTER ENSEMBLE
GUIDANCE IS IN GOOD AGREEMENT OF SHORTWAVE TROUGHS DIVING DOWN
THE AK/BC COASTLINES AND ACROSS THE PACNW TUES/WED AND THURSDAY,
WHICH WILL BRING ANOTHER ROUND OF LIGHT MOUNTAIN RAIN SHOWERS
ACROSS THE FORECAST AREA THOSE DAYS (CONFIDENCE 55-75%).
AS MENTIONED EARLIER, BREEZY WINDS HAVE DEVELOPED IN THE LOWER
ELEVATIONS TODAY, AND ARE EXPECTED TO PERSIST THROUGH MUCH OF
THE WEEK AS THE TROUGHING PATTERN HOLDS OVER THE PACNW. THE
STRONGEST WINDS OF THE WEEK WILL DEVELOP TOMORROW AFTERNOON AS
A SURFACE LOW DEVELOPS IN NORTHERN MT, RESULTING IN A
TIGHTENING CROSS-CASCADE PRESSURE GRADIENT. WINDS WILL GENERALLY
BE 15-30 MPH WITH GUSTS UP TO 40 MPH, HOWEVER WINDS THROUGH THE
KITTITAS VALLEY ARE EXPECTED TO INCREASE TO 25-35MPH AND GUSTS
TO AROUND 50 MPH TOMORROW (CONFIDENCE 75-85%). OTHERWISE, DAILY
WINDS WILL BE 15-25 MPH WITH GUSTS TO AROUND 35 MPH THROUGHOUT
THE WEEK.
LASTLY, THE PERSISTENT TROUGH PATTERN WILL KEEP TEMPERATURES
MUCH COOLER THAN NORMAL THROUGH THE WEEK, WITH AFTERNOON
TEMPERATURES GENERALLY 5 TO 15 DEGREES BELOW NORMAL (CONFIDENCE
60-75%). THIS MEANS THAT AFTERNOON TEMPERATURES IN THE LOWER
ELEVATIONS WILL BE IN THE 70S, WITH LOCALLY 80S, THROUGHOUT MUCH
OF THE WEEK. IN THE MOUNTAINS, MID-ELEVATIONS WILL GENERALLY BE
IN THE UPPER 50S TO 60S, WITH LOWER TO MID 50S IN THE HIGH-
ELEVATIONS. LAWHORN/82
AVIATION /18Z TAFS THROUGH 18Z SUNDAY/
WESTERLY WINDS WILL
BECOME INCREASINGLY BREEZY ACROSS THE REGION THIS FORECAST
PERIOD. MOST SITES ARE SEEING WINDS ABOVE 12 KTS WITH GUSTS
NEARING 20-30KTS EXCEPT BDN, WHICH WILL SEE WINDS AFTER 19Z.
DLS/YKM ARE BOTH ALSO EXPECTING SOME WIND SHEAR WS019/28035KT
FOR DLS AND WS020/31040KT FOR YKM. LASTLY, BDN/RDM HAVE A 30%
CHANCE OR LESS OF ISOLATED VICINITY THUNDERSTORMS AFTER 21Z
PERSISTING THROUGH 00Z.
PRELIMINARY POINT TEMPS/POPS
PDT 46 73 47 72 / 10 10 10 0
ALW 52 74 52 72 / 10 10 10 20
PSC 50 81 50 78 / 0 0 0 0
YKM 49 81 51 81 / 10 10 0 0
HRI 48 77 48 75 / 0 0 0 0
ELN 46 71 48 72 / 10 10 0 0
RDM 36 67 35 70 / 20 0 0 0
LGD 44 66 45 69 / 30 20 10 10
GCD 39 66 40 71 / 50 20 10 0
DLS 52 73 52 72 / 10 0 0 0
PDT WATCHES/WARNINGS/ADVISORIES
WA...WIND ADVISORY FROM 10 AM TO 11 PM PDT SUNDAY FOR WAZ026.
OR...NONE.
DISCUSSION...82
AVIATION...90
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