012
FXUS66 KPDT 262222
AFDPDT
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PENDLETON OR
322 PM PDT SAT SEP 26 2026
KEY MESSAGES
- LIGHT MOUNTAIN SHOWERS TUESDAY, WITH SOME UNCERTAINTY IN THE
PATTERN GOING THROUGH THE MIDWEEK.
- DRY CONDITIONS WITH LIGHT WINDS THROUGH TOMORROW, WITH BREEZY
WINDS DEVELOPING TUESDAY.
- NEAR TO BELOW NORMAL TEMPERATURES THROUGH THE PERIOD WITH
FREEZING TEMPERATURES POSSIBLE IN LOWER VALLEYS.
DISCUSSION
THE TROUGH THAT BROUGHT WINDY AND RAINY CONDITIONS YESTERDAY HAS
MOVED OFF TO THE NORTHEAST INTO CANADA. GUIDANCE ADVERTISES THAT
A SECOND TROUGH WILL DRAW ONSHORE MORE TOWARDS NORTHERN
CALIFORNIA, ALLOWING SPLIT FLOW TO TAKE EFFECT IN THE AREA. THE
TROUGH WILL DIG SOUTH ENOUGH (75-85% CHANCE) THAT MOST OF THE
IMPACTS WILL STAY IN THE MOUNTAIN AREAS WITH LIGHT MOUNTAIN
SHOWERS (20-30% CHANCE). HIGHER CHANCES (50-70% CHANCE) DEVELOP
ACROSS THE CASCADES WITH WETTING RAINS POSSIBLE NEAR SNOQUALMIE
(50-70% CHANCE). AT THE SAME TIME, THE SPLIT FLOW ALOFT WILL
ALLOW CALMER WEATHER CONDITIONS WITH LIGHTS WINDS AND SLIGHTLY
COOLER THAN AVERAGE TEMPERATURES. FREEZING TEMPERATURES IS
POSSIBLE TONIGHT IN PARTS OF LOWER VALLEY'S IN THE BLUES AND
WALLOWA'S, BUT CONFIDENCE IS LOW (10-30% CHANCE) THAT FREEZING
TEMPERATURES WILL BE PROLONG DUE TO EXPECTED CLOUD COVER COMING
THROUGH OVERNIGHT THAT WILL LEVEL OUT TEMPERATURES BY THE LATE
EVENING TO EARLY MORNING HOURS.
UNCERTAINTY WITH THE PATTERN STARTS WEDNESDAY/THURSDAY, WITH
GUIDANCE NOT IN AGREEMENT HOW IT WANTS TO HANDLE THE SYSTEM
WITH STRENGTH AND TIMING. GUIDANCE IS SPLIT ALMOST THREE EVENLY
WAYS IF BY THE TIME THURSDAY THAT A RIDGE, TROUGH, OR ZONAL FLOW
WILL BE ALOFT. THIS WILL EITHER ALLOW MOUNTAIN SHOWERS IN THE
CASCADES TO CONTINUE (32% OF MEMBERS) OR DRY OUT AS THE RIDGE
AXIS TAKES OVERHEAD. EITHER WAY, NOT EXPECTING ANYTHING TOO
IMPACTFUL OTHER THAN SOME LIGHT TO MODERATE PRECIPITATION IN THE
MOUNTAIN REGIONS. WILL NEED TO CONTINUE MONITORING TO HAVE A
GOOD PICTURE OF THE WEEK AHEAD.
AVIATION /00Z TAFS THROUGH 00Z MONDAY/
VFR CONDITIONS PREVAIL THROUGHOUT THE REGION. CLOUD HEIGHTS
SHOULD REMAIN HIGH THROUGH THE TAF PERIOD. KRDM/KBDN AN
OCCASIONAL GUSTS ARE EXPECTED AT THE BEGINNING OF THE PERIOD.
AN OCCASIONAL GUSTS AT KRDM TOWARD THE END OF THE PERIOD IS
EXPECTED. OVERALL THE REGION SHOULD EXPECT CALM WINDS THAT
FOLLOW DIURNAL PATTERNS.
PRELIMINARY POINT TEMPS/POPS
PDT 37 63 37 70 / 0 0 0 0
ALW 41 65 43 71 / 0 0 0 0
PSC 40 71 40 74 / 0 0 0 0
YKM 41 67 41 71 / 0 0 0 0
HRI 40 68 39 73 / 0 0 0 0
ELN 36 63 36 67 / 0 0 0 0
RDM 33 63 31 70 / 0 0 0 0
LGD 38 66 37 70 / 0 0 0 0
GCD 40 70 37 71 / 0 0 0 0
DLS 46 71 45 74 / 0 0 0 0
PDT WATCHES/WARNINGS/ADVISORIES
WA...NONE.
OR...NONE.
DISCUSSION...95
AVIATION...18
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