993
FXUS66 KPDT 102110
AFDPDT
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PENDLETON OR
210 PM PDT FRI APR 10 2026
KEY MESSAGES
- SHOWER AND THUNDERSTORM CHANCES INCREASE THROUGH SATURDAY, BUT
LINGER INTO SUNDAY.
- ANOTHER SYSTEM WILL IMPACT THE REGION AROUND MIDWEEK AND COULD
BRING SOME MOUNTAIN SNOW.
- RIVERS, ESPECIALLY THE NACHES AND SOME POINTS ON THE GRANDE
RONDE ARE RUNNING HIGH.
DISCUSSION
AN UPPER LEVEL TROUGH WILL MOVE ONSHORE IN NORTHERN CALIFORNIA
THIS AFTERNOON/EVENING AS A LARGE UPPER LOW APPROACHES. THIS
UPPER LOW WILL THEN MOVE ONSHORE IN NORTHERN CALIFORNIA SATURDAY
NIGHT/SUNDAY MORNING AND MOVE EASTWARD. AS THE LOW MOVES, ITS
ASSOCIATED TROUGH WILL MOVE ACROSS THE WESTERN STATES THROUGH
MONDAY, WHICH WILL KEEP UNSETTLED WEATHER OVER THE AREA. SOME
WEAK RIDGING, THEN A MORE ZONAL FLOW WILL DRY THINGS OUT FOR
LATER MONDAY INTO TUESDAY.
SHOWERS AND ISOLATED THUNDERSTORMS (20-30 PERCENT) ARE EXPECTED
THIS AFTERNOON MAINLY OVER CENTRAL OREGON AND THE JOHN DAY
HIGHLANDS. ON SATURDAY, THERE WILL BE RAIN CHANCES JUST ABOUT
EVERYWHERE, WITH THE HIGHEST PROBABILITIES (>60 PERCENT) MAINLY
IN CENTRAL OREGON AND ACROSS THE MOUNTAINS. THUNDERSTORMS
CHANCES ARE MORE WIDESPREAD ACROSS THE AREA AS WELL THE OVERALL
PROBABILITIES STILL REMAIN GENERALLY 25 PERCENT OR LESS. AS THE
TROUGH MIGRATES EAST ON SUNDAY, THE HIGHEST RAIN (AND
THUNDERSTORM CHANCES WILL MAINLY BE OVER EASTERN OREGON AND THE
JOHN DAY HIGHLANDS.
WHILE CAPE VALUES THROUGH SUNDAY ARE SEVERAL HUNDRED J/KG IN
AREAS AND LI VALUES ARE AS LOW AS -2 TO -3 DEGREES CELSIUS.
QUESTIONS REMAIN AS TO HOW ANY CLOUD COVER AND ANY BREAKS IN
THAT CLOUD COVER WILL PLAY IN TO CONVECTIVE INITIATION.
ANOTHER LOW, THIS TIME DROPPING DOWN FROM CANADA WILL IMPACT
THE REGION AROUND MIDWEEK, BRINGING ANOTHER ROUND OF
PRECIPITATION, SOME LATE SEASON MOUNTAIN SNOW AND TEMPERATURES
ABOUT 5 DEGREES BELOW NORMAL.
LASTLY, WITH THE RAINFALL EXPECTED OVER THE NEXT FEW DAYS,
RIVERS, ESPECIALLY THE NACHES AND A FEW POINTS ON THE GRANDE
RONDE, WILL CONTINUE TO RUN HIGH AND ARE FORECAST TO REACH
ACTION STAGE. OTHER RIVERS WILL HAVE SIGNIFICANT IN-BANKS RISES
BUT WILL REMAIN BELOW ACTION STAGE.
AVIATION /18Z TAFS THROUGH 18Z SATURDAY/
PREDOMINANTLY VFR CONDITIONS ARE ANTICIPATED FOR THE NEXT 24
HOURS. HOWEVER, CHANCES OF SUB-VFR VSBYS AND/OR CIGS IN SHOWERS
AND/OR THUNDERSTORMS INCREASE THIS AFTERNOON AND EVENING TO
30-50 PERCENT FOR BDN/RDM WITH LOWER 10-30 PERCENT CHANCES OF
SUB-VFR CONDITIONS FOR ALL OTHER SITES OVERNIGHT INTO SATURDAY
MORNING. WINDS OF 10 KTS OR LESS ARE FORECAST, THOUGH GUSTY
OUTFLOW WINDS IN THE VICINITY OF SHOWERS AND THUNDERSTORMS WILL
LIKELY (80 PERCENT CONFIDENCE) DISRUPT THE BACKGROUND WIND FIELD
SUCH THAT CONFIDENCE IN DETAILS OF THE WIND FORECAST IS LOW-
MEDIUM (30-60 PERCENT) FOR ANY GIVEN SITE.
PRELIMINARY POINT TEMPS/POPS
PDT 46 65 43 61 / 40 70 20 60
ALW 49 66 46 62 / 40 70 30 70
PSC 49 71 44 69 / 30 50 10 30
YKM 47 66 41 69 / 30 50 10 10
HRI 47 69 44 66 / 30 50 10 40
ELN 45 60 39 63 / 30 50 10 10
RDM 39 60 37 55 / 80 70 60 60
LGD 45 62 41 56 / 50 80 60 90
GCD 43 61 39 53 / 60 70 70 100
DLS 50 68 47 66 / 50 60 20 30
PDT WATCHES/WARNINGS/ADVISORIES
WA...NONE.
OR...NONE.
DISCUSSION...77
AVIATION...86
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