318
FXUS66 KPDT 302109
AFDPDT
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PENDLETON OR
209 PM PDT MON MAR 30 2026
KEY MESSAGES
1. DRY AND COOL CONDITIONS THIS WEEK
2. TROUGH WILL BRING INCREASED CHANCES OF PRECIPITATION MIDWEEK
3. RIDGE OVER THE WEEKEND WILL BRING BACK DRY AND WARMER CONDITIONS
DISCUSSION
CURRENT RADAR SHOWS MUCH OF THE PRECIPITATION IS TO THE SOUTH MOVING
ACROSS CENTRAL OR THROUGH THE OCHOCO-JOHN DAY HIGHLANDS AND INTO
SOUTHERN WALLOWA. THIS IS WHERE THE PRECIPITATION WILL STAY FOR THE
REMAINDER OF TODAY. GROUND OBSERVATIONS SHOW THE AMOUNTS TO BE LIGHT
BETWEEN 0.01-0.04 INCHES OF RAINFALL. SOME WEBCAMS SHOW VERY LIGHT
SNOW THAT IS NOT STICKING TO THE PAVEMENT. LIGHT SHOWERS WILL
CONTINUE THROUGH THE DAY TODAY BRINGING WITH IT RAIN AMOUNTS NEARING
0.07-0.09 INCHES WITH WITH 50-70% CONFIDENCE.
MODELS SHOW THE FRONT THAT JUST CROSSED THE REGION TO SLIGHTLY
REBOUND BACK INTO THE AREA MOVING A BIT FARTHER NORTH. LREF RAW
ENSEMBLES SHOW THAT THERE IS 50-60% OF THE MEMBERS IN AGREEMENT THAT
THIS SHIFT NORTH WILL BRING WITH IT 15-25% CHANCES OF ISOLATED
THUNDERSTORMS THROUGH GRANT AND COOK COUNTIES TUESDAY AFTERNOON AND
30-50% PROBABILITIES OF RAIN THROUGH THE OCHOCO-JOHN DAY HIGHLANDS,
EVEN SPILLING OVER THE BLUES AND INTO THE FOOTHILLS. ACCUMULATIONS
WILL BE HIGHEST THROUGH THE HIGHLANDS WITH ACCUMULATIONS NEARING
0.10-0.20 INCHES WITH 50-70% OF THE NBM RAW ENSEMBLES IN AGREEMENT
WHILE LOWER ELEVATIONS ALONG THE FOOTHILLS WILL SEE 0.03-0.07 INCHES.
LIGHT SNOW SHOWERS WILL OCCUR ABOVE 5500 FEET WITH ACCUMULATIONS
LESS THAN 0.2 INCHES WITH 70-80% CONFIDENCE. WEDNESDAY AHEAD OF THE
FRONT, LREF SHOWS 15% PROBABILITIES OF ISOLATED THUNDERSTORMS ALONG
THE LEADING EDGE OF THE FRONT. ISOLATED THUNDERSTORMS WOULD FORM
ALONG THE WESTERN SLOPES OF THE EASTERN MOUNTAINS.
WEDNESDAY AND THURSDAY MODELS SHOW A STRONG UPPER LEVEL LOW WILL
BEGIN TO MOVE IN OFF THE COAST OF B.C. AND AHEAD OF IT WILL BE
ANOTHER FRONT. MODELS SHOW THIS SYSTEM TO BE ROBUST WITH INCREASED
CHANCES OF MOUNTAIN SNOW, LOW ELEVATION RAIN AND INCREASED WINDS.
CLUSTERS DO SHOW SOME DEVIATION WITH THE MODELS WITH TIMING,
HOWEVER, ALL MODELS SHOW A ROBUST FRONT MAKING ITS WAY INTO THE
REGION TUESDAY NIGHT/WEDNESDAY MORNING. THE FRONT WILL MOVE ACROSS
THE REGION BRINGING SNOW LEVELS TO NEAR 2000 FT. THIS WILL ALLOW FOR
SOME SNOW SHOWERS ACROSS A GOOD PORTION OF THE REGION WITH THE
HIGHEST AMOUNTS BEING ALONG THE CASCADES. A WINTER WEATHER WATCH HAS
BEEN ISSUED FOR THE EAST SLOPES OF THE OR CASCADES WITH MODELS
SHOWING NEARLY 10-15 INCHES OF ACCUMULATION ALONG SANTIAM PASS WITH
50-80% OF THE RAW ENSEMBLES ARE IN AGREEMENT AND SNOQUALMIE PASS
COULD SEE 3-6 INCHES WITH 30-60% CONFIDENCE AS WELL AS THE HIGHER
PEAKS OF THE NORTHERN BLUES AROUND TOLLGATE. THE EASTERN MOUNTAINS
COULD SEE UP TO 1-1.5 INCHES WITH 60-80% CONFIDENCE. THE LOWER
ELEVATIONS MODELS ARE SHOWING QPF AMOUNTS NEARING 0.15-0.30 INCHES
WITH 60-80% CONFIDENCE. THERE IS SHOW SHADOWING SHOWING UP IN THE
MODELS RUNS AND PORTIONS OF THE WESTERN BASIN AS WELL AS THROUGH
CENTRAL AND NORTH CENTRAL OR WILL ONLY SEE 0.05-0.15 INCHES OF RAIN
WEDNESDAY THROUGH THURSDAY WITH 50-70% CONFIDENCE. LASTLY, WINDS
WILL BECOME A BIT BREEZY AS THE FRONT MOVES THROUGH THURSDAY BRINING
70-80% PROBABILITIES OF 25-30 MPH GUSTS ACROSS THE REGION.
THURSDAY NIGHT INTO FRIDAY MORNING MODELS SHOW THE NEXT INCOMING
SYSTEM COMING IN FROM OFF THE COAST. AN UPPER LEVEL RIDGE ILL SET UP
OVER THE REGION BRINGING WARMER AND DRIER CONDITIONS. CLUSTERS SHOW
THAT THE MAIN DIFFERENCE BETWEEN THE MODELS WILL BE POSITIONING OF
THE UPPER LEVEL RIDGE. LOOKING AT IN HOUSE MODEL COMPARISONS,
TEMPERATURES WILL BE ANYWHERE FROM 5 TO 10 DEGREES ABOVE SEASONAL
NORMAL THROUGH THE BASIN AND ADJACENT VALLEYS AND 10-15 DEGREES
ABOVE SEASONAL AVERAGE FOR THE OREGON POTION OF THE CWA.
TEMPERATURES WILL START OFF IN THE LOW TO MID 60S BEFORE INCREASING
AND SEEING UPPER 60S TO LOW 70S IN SOME AREAS. CONFIDENCE IN THE
TEMPERATURES IS 50-70% PEAKING SUNDAY. 90
AVIATION /18Z TAFS THROUGH 18Z TUESDAY/
THE RDM AND BDN TERMINALS ARE IN A STRATUS AND LIGHT -SN/-RA
ENVIRONMENT AS MOISTURE IS LIFTED ACROSS THE OREGON CASCADES
TODAY. CEILING IMPROVEMENT FROM THIS MORNINGS LIFR CONDITIONS
IS LIKELY TO BE MAINTAINED (70%) TO AT LEAST ABOVE THE IFR
LEVEL AS THE PROBABILITY OF CEILINGS LESS THAN 1 KFT IS 30% AT
BEND AND 10% AT REDMOND BY 21Z BASED ON HREF (ENSEMBLES).
ELSEWHERE EXPECT VFR CONDITIONS AND LIGHT WINDS THOUGH THIS TAF
PERIOD.
PRELIMINARY POINT TEMPS/POPS
PDT 29 50 38 56 / 10 20 20 90
ALW 32 52 40 56 / 0 20 20 90
PSC 29 55 38 58 / 0 10 10 80
YKM 28 54 35 53 / 0 0 10 80
HRI 29 54 38 58 / 10 10 10 80
ELN 26 50 32 47 / 0 0 0 80
RDM 29 53 35 53 / 40 30 10 90
LGD 28 53 38 53 / 20 50 60 100
GCD 34 55 38 52 / 60 80 70 100
DLS 34 55 41 55 / 10 20 30 100
PDT WATCHES/WARNINGS/ADVISORIES
WA...NONE.
OR...WINTER STORM WATCH FROM LATE TUESDAY NIGHT THROUGH THURSDAY
AFTERNOON FOR ORZ509.
DISCUSSION...90
AVIATION...71
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