263
FXUS66 KPDT 222148
AFDPDT
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PENDLETON OR
248 PM PDT MON JUN 22 2026
KEY MESSAGES
- MODERATE HEATRISK THROUGH IN THE LOWER ELEVATIONS THROUGH
WEDNESDAY
- WEAK SYSTEM PASSAGE WEDNESDAY INTO THURSDAY WILL BRING
ISOLATED THUNDERSTORM CHANCES TO THE CASCADE EAST SLOPES, WITH
BREEZY WINDS ELSEWHERE
- BREEZY WINDS, COOLER TEMPERATURES, AND MOUNTAIN SHOWERS FRIDAY
THROUGH THE WEEKEND.
DISCUSSION
TODAY THROUGH TUESDAY: DESPITE A RIDGE OF HIGH
PRESSURE DEVELOPING OVER THE REGION TODAY, SATELLITE SHOWS
FIELDS OF CUMULUS FORMING OVER THE WA CASCADES AND NORTHERN
BLUES THIS AFTERNOON.
WARMING CONDITIONS WITH A FEW AFTERNOON BREEZES WILL BE THE MAIN
TREND THE REST OF TODAY AND TOMORROW AS AN UPPER LEVEL RIDGE
SLIDES ACROSS THE PACNW. WINDS WILL REMAIN MOSTLY LIGHT THROUGH
TOMORROW, WHILE AFTERNOON TEMPERATURES WILL WARM ANOTHER 2 TO 4
DEGREES INTO THE LOWER TO MID 90S ACROSS THE LOWER ELEVATION
AREAS.
WEDNESDAY AND THURSDAY: THE UPPER RIDGE WILL PUSH EAST
WEDNESDAY, ALLOWING A MID-LEVEL SHORTWAVE TO SLIDE ACROSS THE
PACNW DURING THE DAY. AT THE SURFACE, A THERMAL TROUGH WILL
CROSS THE CASCADES INTO THE INTERMOUNTAIN PACNW, WHICH WILL
BRING INCREASING UNSTABLE CONDITIONS AND THE WARMEST
TEMPERATURES OVER THE FORECAST AREA WEDNESDAY AFTERNOON. WHILE
CONDITIONS WILL REMAIN MOSTLY DRY ACROSS THE AREA, A WEAK
MOISTURE PUSH WITH SHORTWAVE PASSAGE AND INCREASED INSTABILITY
ACROSS THE CASCADE EAST SLOPES WILL RESULT IN CHANCES (15-30%)
OF ISOLATED THUNDERSTORMS AND SHOWERS DEVELOPING IN THE
AFTERNOON AND EVENING. OTHERWISE, THE CROSS-CASCADE PRESSURE
GRADIENT WILL TIGHTEN BY THE LATE AFTERNOON, RESULTING IN
BREEZY WINDS (10 DEVELOPING THROUGH THE CASCADE GAPS AND
PORTIONS OF THE COLUMBIA BASIN THROUGH THE EVENING. LOCALIZED
PORTIONS OF THE COLUMBIA BASIN/GORGE MAY BRIEFLY SEE LOW RHS
(10-20%) COMBINE WITH THESE BREEZY CONDITIONS LATE IN THE DAY,
RESULTING IN ELEVATED FIRE WEATHER CONDITIONS (CONFIDENCE
60-70%)
ZONAL FLOW WILL DEVELOP BEHIND THE SHORTWAVE EXIT EARLY
THURSDAY, KEEPING DRIER CONDITIONS ACROSS MUCH OF THE FORECAST
AREA. BREEZY WINDS (15-25MPH WITH GUSTS UP TO 40 MPH) WILL
REDEVELOP LATE IN THE MORNING THROUGH THE AFTERNOON ACROSS THE
LOWER ELEVATIONS AS PRESSURE GRADIENTS REMAIN TIGHTENED AHEAD OF
A SURFACE LOW SWINGING INTO CENTRAL BC. THE INCREASED WINDS AND
LOW RHS (10-20%) ACROSS THE COLUMBIA BASIN AND PORTIONS OF NORTH
CENTRAL OREGON WILL RESULT IN ELEVATED FIRE WEATHER CONDITIONS
IN THE AFTERNOON, WITH INCREASING CONFIDENCE (65-80%) THAT
CRITICAL WIND/RH THRESHOLDS WILL BE MET THURSDAY.
FRIDAY THROUGH THE WEEKEND: COOLER TEMPERATURES, BREEZY WINDS,
AND MOUNTAIN SHOWERS WILL BE THE TREND INTO THE WEEKEND, THANKS
TO AN UPPER LOW DIVING DOWN THE BC COASTLINE INTO THE PACNW.
ENSEMBLE GUIDANCE IS IN GOOD AGREEMENT THROUGH THE WEEKEND THAT
THE UPPER LOW WILL APPROACH THE PACNW BY FRIDAY MORNING, WITH
SHOWERS PUSHING EAST WITH A FRONTAL BOUNDARY EARLY FRIDAY. BY
THE AFTERNOON, SHOWERS WILL RETREAT MAINLY TO THE MOUNTAINS AS
THE FRONTAL BOUNDARY EXITS INTO THE EASTERN MOUNTAINS AND THE
UPPER LOW ENTERS INTO THE PACNW (CONFIDENCE 50-65%). INCREASING
INSTABILITY COMBINED WITH THE FRONTAL PASSAGE WILL ALSO RESULT
IN ISOLATED THUNDERSTORMS DEVELOPING ACROSS THE EASTERN
MOUNTAINS FRIDAY AFTERNOON. MOUNTAIN SHOWERS WILL CONTINUE
THROUGHOUT THE WEEKEND AS THE LOW CONTINUES TO SWING THROUGH THE
AREA, WITH DECENT AGREEMENT AMONGST ENSEMBLE MEMBERS THAT THE
UPPER LOW WILL BE CENTERED EAST OF THE PACNW BY SUNDAY
AFTERNOON, WITH BROAD TROUGHING REMAINING OVER THE REGION. OTHER
THAN PRECIPITATION, BREEZY WINDS (15-25MPH WITH GUSTS UP TO 45
MPH) WILL CONTINUE INTO THE WEEKEND ACROSS THE LOWER ELEVATIONS,
WITH THE STRONGEST WINDS (20-35MPH WITH GUSTS 40-50 MPH)
DEVELOPING THROUGH THE CASCADE GAPS SATURDAY AFTERNOON
(CONFIDENCE 45-65%). LAWHORN/82
AVIATION /18Z TAFS THROUGH 18Z TUESDAY/
VFR CONDITIONS TO
PREVAIL THROUGH THE PERIOD. WINDS WILL BE LIGHT WITH
DIURNALLY/TERRAIN DRIVEN WIND SHIFTS. LAWHORN/82
FIRE WEATHER
DRY AND WARM CONDITIONS WILL CONTINUE THROUGH
THURSDAY. BREEZY WINDS WILL DEVELOP THROUGH THE CASCADE GAPS
WEDNESDAY WITH LOCALIZED CRITICAL FIRE WEATHER CONDITIONS,
WINDS AND CRITICAL FIRE WEATHER CONDITIONS BECOMING WIDESPREAD
THURSDAY. ISOLATED THUNDERSTORMS WILL ALSO BE POSSIBLE ALONG THE
CASCADE CREST AND EAST SLOPES WEDNESDAY AFTERNOON. BREEZY WINDS,
COOLER TEMPERATURES, AND MOUNTAIN SHOWERS ARE EXPECTED FRIDAY
THROUGH THE WEEKEND.
PRELIMINARY POINT TEMPS/POPS
PDT 53 91 55 91 / 0 0 0 0
ALW 58 92 61 93 / 0 0 0 0
PSC 55 94 58 96 / 0 0 0 0
YKM 59 92 61 94 / 0 0 0 10
HRI 55 93 58 94 / 0 0 0 0
ELN 56 89 59 90 / 0 0 0 20
RDM 49 89 50 88 / 0 0 0 10
LGD 50 89 53 89 / 0 0 10 0
GCD 48 94 50 91 / 0 0 0 10
DLS 62 95 64 93 / 0 0 0 0
PDT WATCHES/WARNINGS/ADVISORIES
WA...HEAT ADVISORY UNTIL 11 PM PDT TUESDAY FOR WAZ024.
OR...HEAT ADVISORY UNTIL 11 PM PDT TUESDAY FOR ORZ041.
DISCUSSION...82
AVIATION...82
FIRE WEATHER...82
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