948
FXUS66 KPDT 211735
AFDPDT
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PENDLETON OR
1035 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 /18Z TAFS THROUGH 18Z TUESDAY/
VFR CONDITIONS ARE FORECASTED THROUGH THE TAF PERIOD AT ALL
SITES. ALL SITES WILL SEE RELATIVELY CLEAR SKY CONDITIONS
THROUGHOUT THE PERIOD AS WELL WITH FEW-SCATTERED HIGH CLOUD
COVER THROUGH THE MORNING-EARLY AFTERNOON. OTHERWISE, WINDS WILL
BE GENERALLY LIGHT WITH SUSTAINED WINDS OF LESS THAN 12 KTS,
WITH THE EXCEPTION OF DLS EXPERIENCING GUSTS UP TO 15 MPH LATER
IN THE AFTERNOON. AMES/01
PRELIMINARY POINT TEMPS/POPS
PDT 84 52 76 46 / 0 0 0 0
ALW 85 58 77 52 / 0 0 0 0
PSC 86 55 80 49 / 0 0 0 0
YKM 84 54 80 48 / 0 0 0 0
HRI 86 56 79 49 / 0 0 0 0
ELN 80 50 71 44 / 0 0 0 0
RDM 83 45 75 38 / 0 0 0 0
LGD 83 52 79 45 / 0 0 0 0
GCD 85 51 80 45 / 0 0 0 0
DLS 85 56 75 51 / 0 0 0 0
PDT WATCHES/WARNINGS/ADVISORIES
WA...NONE.
OR...NONE.
UPDATE...99
DISCUSSION...95
AVIATION...01
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page