130
FXUS66 KPDT 232241
AFDPDT
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PENDLETON OR
341 PM PDT WED SEP 23 2026
KEY MESSAGES
1. DRY CONDITIONS WILL REMAIN THROUGH THURSDAY AFTERNOON
2. MOUNTAIN PRECIPITATION THURSDAY NIGHT BECOMING WIDESPREAD FRIDAY
3. BREEZY CONDITIONS FRIDAY
DISCUSSION
CURRENT SATELLITE SHOWS MOSTLY CIRRUS CLOUDS MOVING OVER THE REGION.
DRY CONDITIONS WILL PERSIST TODAY WITH TEMPERATURES IN THE UPPER 60S
TO LOW 70S AND LIGHT DIURNALLY DRIVEN WINDS.
CAMS MODELS SHOW WEAK RIDGING REMAINING OVER THE REGION THROUGH THE
DAY TODAY. THIS WILL KEEP THE REGION UNDER DRY AND WARM CONDITIONS.
LOOKING AT IN OFFICE CALCULATIONS, TEMPERATURES ARE 2 TO 5 DEGREES
ABOVE SEASONAL AVERAGES FOR THIS TIME OF YEAR. TEMPERATURES THURSDAY
ARE ALSO ABOVE NORMAL BY NEARLY 10 TO 15 DEGREES WITH TEMPERATURES
IN THE MID TO UPPER 70S WITH SOME ISOLATED 80S IN CENTRAL OR AND THE
JOHN DAY BASIN.
MODELS SHOW THE UPPER LEVEL TROUGH TO BEGIN TRAVERSING SOUTHWARD AND
INTO THE REGION BY THURSDAY AFTERNOON BRINGING WITH IT
SOUTHWESTERLY FLOW. COOLER TEMPERATURES WILL ACCOMPANY THE PATTERN
SHIFT AS WELL AS INCREASED PRECIPITATION CHANCES. TEMPERATURES
FRIDAY WILL BE NEARLY 10 TO 15 DEGREES COOLER THAN THURSDAY.
MOUNTAIN SHOWERS ARE EXPECTED TO BEGIN AFTER 8 PM THURSDAY NIGHT
BECOMING WIDESPREAD AFTER 5 AM FRIDAY. MODEL SUGGESTED 24 HOUR
ACCUMULATIONS ARE BETWEEN 0.01-0.05 IN CENTRAL OR (60-80%) TO 0.05-
0.10 IN THROUGH THE COLUMBIA BASIN AND FOOTHILLS OF THE BLUES (50-
70%), 0.10-0.25 INCHES ALONG THE EASTERN SLOPES AND THE BLUE
MOUNTAINS (60-80%) AND LASTLY, 0.50-1 INCH ALONG THE CASCADE CRESTS
(50-70%). MODELS SHOW THE SYSTEM TO SHORT LIVED BRINGING DRY
CONDITIONS BEHIND IT. SATURDAY AND SUNDAY WILL SEE DRY CONDITIONS
RETURN WITH TEMPERATURES CONTINUING TO COOL.
MODELS ARE ALSO INDICATING A SURFACE LEVEL LOW WILL ACCOMPANY THE
TROUGH WITH A FRONT SLIGHTLY AHEAD OF THE SYSTEM. THIS FRONT WILL
BRING INCREASED WINDS OVER THE AREA STARTING THURSDAY NIGHT AND
CONTINUING AND INCREASING THROUGH FRIDAY. WITH THE TROUGH DIGGING
FARTHER SOUTH, PRESSURE GRADIENTS ACROSS THE REGION WILL TIGHTEN
MORE OVER THE CENTRAL CASCADES NEAR THE GORGE. THE AFFECTED AREAS
WILL BE THE GORGE, LOWER COLUMBIA BASIN AND THE FOOTHILLS OF THE
SOUTHERN BLUES. RAW ENSEMBLES SHOW THE LIKELIEST LOCATION TO BE
THROUGH THE GORGE AND THE SOUTHERN BLUE FOOTHILLS WITH 60-70% OF THE
ENSEMBLES IN AGREEMENT WITH UP TO 25-30 MPH SUSTAINED WINDS AND NEAR
45 MPH GUSTS. THE REMAINING LOCATIONS HAVE A 50-60% CHANCE OF SEEING
25 SUSTAINED WINDS AND GUSTS NEAR 35-40 MPH. MUCH LIKE THE
PRECIPITATION, WINDS WILL SETTLE BACK TO DIURNAL BY SATURDAY
MORNING. 90
AVIATION /00Z TAFS THROUGH 00Z FRIDAY/
LIGHT WINDS (UNDER 10 KT) AT ALL TERMINALS THROUGH THE PERIOD
WITH THE EXCEPTION OF SOME MARGINAL GUSTS (15-25 KTS) DEVELOPING AT
THE BDN TERMINAL AFTER ABOUT 21Z. VFR THROUGH THE TAFS.
PRELIMINARY POINT TEMPS/POPS
PDT 46 79 50 69 / 0 0 10 80
ALW 52 80 55 70 / 0 0 0 80
PSC 48 79 53 72 / 0 0 20 80
YKM 48 74 54 65 / 0 0 80 40
HRI 48 79 53 71 / 0 0 20 80
ELN 42 70 48 59 / 0 0 80 70
RDM 40 83 45 60 / 0 0 80 20
LGD 47 86 52 68 / 0 0 0 60
GCD 48 88 53 68 / 0 0 0 40
DLS 51 78 55 66 / 0 0 90 70
PDT WATCHES/WARNINGS/ADVISORIES
WA...NONE.
OR...NONE.
DISCUSSION...07/90
AVIATION...71
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