898
FXUS66 KPDT 211127
AFDPDT
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PENDLETON OR
427 AM PDT MON SEP 21 2026
KEY MESSAGES
- TEMPERATURES CONTINUE TO WARM FURTHER TODAY WITH HIGHS
REACHING THE LOW TO MID 80S BY THE LATE AFTERNOON HOURS.
- COOLER PATTERN WITH POSSIBLE RAIN CHANCES, ESPECIALLY ALONG
THE MOUNTAINS LATER THIS WEEK.
- DIURNAL WINDS WITH GENERAL BREEZY WINDS DEVELOPING TUESDAY AND
FRIDAY, ESPECIALLY NEAR THE CASCADE GAPS.
DISCUSSION
RADAR AND SATELLITE IMAGERY CONTINUES TO DISPLAY DRY CONDITIONS
WITH CLEAR TO MOSTLY CLEAR SKIES THANKS TO THE UPPER LEVEL RIDGE
OF HIGH PRESSURE CONTINUING TO EFFECT THE AREA. THIS WILL ALLOW
TEMPERATURES TO CONTINUE WARMING A FEW MORE DEGREES THROUGH
TODAY, WITH TEMPERATURES IN MOST OF THE LOWER ELEVATION AREAS TO
RISE IN THE LOW TO MID 80S. THE UPPER LEVEL RIDGE WILL CONTINUE
BRINGING WARM SOUTHWEST FLOW BEFORE ANOTHER SYSTEM ENTERS THE
AREA BY TUESDAY. ON THE FIRE WEATHER SIDE, WINDS REMAIN LIGHT
AND VARIABLE TODAY, BUT WILL PICK-UP TUESDAY AFTERNOON WITH
BREEZY WINDS DEVELOPING ACROSS THE COLUMBIA BASIN, KITTITAS
VALLEY, AND CASCADE GAPS. MINIMUM RELATIVE HUMIDITIES WILL
CONTINUE TO DROP INTO THE 20 TO 30 PERCENT RANGE, WITH LOCALLY
LOWER VALUES DOWN TO 15 TO 20 PERCENT NEAR CENTRAL OREGON.
BY TUESDAY, GUIDANCE IS IN GOOD AGREEMENT WE'LL SEE OUR NEXT
SYSTEM PUSH THROUGH AS A TROUGH OFFSHORE WILL MOVE IN BRITISH
COLUMBIA AND PUSH THROUGH THE REST OF THE WEEK (>90% CHANCE).
WHAT'S A BIT TRICKY IS HOW THE TROUGH WILL SET-UP WITH TIMING
AND STRENGTH DETERMINING THE AMOUNT OF PRECIP WE'LL GET. FOR
EXAMPLE, THE CLUSTER ANALYSIS BY FRIDAY AFTERNOON HAS 52% OF THE
CLUSTERS HAVING THE TROUGH STRONG ENOUGH TO BRING SOME PRECIP
ACROSS OUR REGION. OF THAT 52%, ONLY 22% HAVE WIDESPREAD
PRECIPITATION ACROSS THE CWA WHILE THE CASCADE MOUNTAIN REGION
ENCOMPASSES ALL 52% OF THE MEMBERS. THE REMAINING 48% HAS A
DRIER SET-UP WITH A WEAKER TROUGH AXIS ACROSS THE PACNW,
RESULTING IN NONE, IF NOT VERY LITTLE, QPF'S. CHANCES OF RAIN
REMAIN HIGHER IN THE CASCADE MOUNTAINS AT 50 TO 70 PERCENT.
MEANWHILE, CHANCES FOR WIDESPREAD QPF'S ACROSS THE BLUES, BASIN
AND OTHER LOWER-ELEVATION SITES, CHANCES OF RAIN FOR THOSE
AREAS REMAIN LOWER AT AROUND 15 TO 25 PERCENT THROUGH FRIDAY.
AVIATION /12Z TAFS THROUGH 12Z TUESDAY/
VFR CONDITIONS PREVAIL THROUGH THE PERIOD WITH THE EXCEPTION OF
YKM EXPERIENCING SOME TEMPORARY MVFR CONDITIONS DUE TO PASSING
HAZE. WILL SEE THIS LIFTING IN THE LATER MORNING HOURS AS
ATMOSPHERIC MIXING IMPROVES BY 14Z. OTHERWISE, NOT EXPECTING ANY
OTHER CIG OR VIS CONDITIONS WITH WINDS GENERALLY LIGHT TO
MODERATE.
PRELIMINARY POINT TEMPS/POPS
PDT 84 52 76 48 / 0 0 0 0
ALW 85 57 77 53 / 0 0 0 0
PSC 86 54 80 49 / 0 0 0 0
YKM 85 54 79 48 / 0 0 0 0
HRI 85 55 78 49 / 0 0 0 0
ELN 80 50 70 44 / 0 0 0 0
RDM 83 44 75 38 / 0 0 0 0
LGD 84 52 79 46 / 0 0 0 0
GCD 85 51 80 46 / 0 0 0 0
DLS 86 56 77 51 / 0 0 0 0
PDT WATCHES/WARNINGS/ADVISORIES
WA...NONE.
OR...NONE.
DISCUSSION...95
AVIATION...95
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