556
FXUS66 KPDT 042246
AFDPDT
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PENDLETON OR
346 PM PDT THU JUN 4 2026
KEY MESSAGES
- SHOWERS AND ISOLATED THUNDERSTORMS ALONG THE CASCADE CREST
FRIDAY AND SATURDAY
- BREEZY CASCADE GAP WINDS TODAY WILL SPREAD TO THE LOWER
ELEVATIONS FRIDAY AND SATURDAY
- DRY CONDITIONS SUNDAY BEFORE AN ACTIVE WEATHER PATTERN RETURNS
THROUGH THE MIDDLE OF NEXT WEEK
DISCUSSION
TODAY THROUGH SATURDAY: SATELLITE IMAGERY TODAY SHOWS MOSTLY
CLEAR CONDITIONS WHILE SURFACE OBSERVATIONS REPORT BREEZY WINDS
THROUGH THE CASCADE GAPS.
DRY CONDITIONS WITH LOCALLY BREEZY CONDITIONS WILL CONTINUE
THROUGH THE REMAINDER OF THE DAY AS THE PACNW SITS UNDER A
QUASI-ZONAL FLOW. FLOW ALOFT WILL GRADUALLY GAIN A SOUTHERLY
COMPONENT TONIGHT THROUGH TOMORROW MORNING AS AN UPPER LOW DROPS
OUT OF THE GULF OF ALASKA, WITH THE LOW ARRIVING JUST OFFSHORE
VANCOUVER ISLAND BY TOMORROW AFTERNOON. THE LOW ARRIVAL WILL
BRING RAIN SHOWERS TO THE WA CASCADE CREST, WHILE A TIGHTENING
CROSS-CASCADE PRESSURE GRADIENT WILL RESULT IN BREEZY WINDS
(15-25 MPH WITH GUSTS UP TO 40 MPH) THROUGH THE CASCADE GAPS
AND LOWER ELEVATION AREAS. WHILE FIRE WEATHER CONCERNS WILL
OVERALL REMAIN LOW, THERE WILL BE ELEVATED CONDITIONS IN THE WA
COLUMBIA BASIN AS AFTERNOON RHS DIP BELOW 25% AND SUSTAINED
WINDS WILL NEAR 20 MPH (CONFIDENCE 30-50%).
SATURDAY, THE UPPER LOW WILL SWING ACROSS THE PACNW, BUT LIMITED
MOISTURE ASSOCIATED WITH THIS SYSTEM WILL CONFINE SHOWER CHANCES
TO THE CASCADE CREST. INCREASING SURFACE INSTABILITY WITH
INCREASED LOW TO MID LEVEL LAPSE RATES ACROSS THE CASCADE
CREST/EAST SLOPES WILL ALSO ALLOW FOR SLIGHT CHANCES (15-25%) OF
ISOLATED THUNDERSTORMS IN THE AFTERNOON AND EARLY EVENING.
OTHERWISE, BREEZY WESTERLY WINDS WILL CONTINUE ACROSS THE LOWER
ELEVATIONS THROUGH SATURDAY EVENING.
SUNDAY THROUGH WEDNESDAY: BY SUNDAY MORNING, MOSTLY DRY
CONDITIONS AND LIGHT WINDS WILL DEVELOP ACROSS THE REGION AS
THE UPPER LOW DEPARTS TO THE EAST AND A TRANSIENT RIDGE MOVES
OVER THE PACNW.
EARLY TO MID NEXT WEEK, ENSEMBLE GUIDANCE IS IN GOOD AGREEMENT
THAT THE PACNW WILL BE UNDER A PROLONGED TROUGHING PATTERN THAT
WILL BRING WIDESPREAD SHOWER CHANCES AS THE TROUGH MEANDERS
ACROSS THE REGION. THERE IS SOME DISAGREEMENT IN THE STRENGTH OF
THE TROUGH AS IT MOVES ACROSS THE PACNW; ABOUT 25% OF MEMBERS
FAVORING A CLOSED LOW, WHICH WOULD RESULT IN HIGHER
PRECIPITATION AMOUNTS AND BETTER THUNDERSTORM CHANCES IN THE
MOUNTAINS TUESDAY INTO WEDNESDAY. DISAGREEMENT IN
POSITION/TIMING OF THE TROUGH/LOW PASSAGE ALSO GROWS INTO THE
MIDDLE OF NEXT WEEK, AS ~30% OF ENSEMBLE MEMBERS FAVOR THE
TROUGH AND SHOWERS EXITING THE REGION WEDNESDAY AFTERNOON, WHILE
THE REMAINING MEMBERS SHOW SHOWERS AND THE TROUGH STILL OVER
THE REGION. CONFIDENCE IN PRECIPITATION CHANCES THROUGH THIS
PERIOD IS MODERATE (60-70%), HOWEVER CONFIDENCE IN TIMING IS LOW
(25-35%). LAWHORN/82
AVIATION /00Z TAFS THROUGH 00Z SATURDAY/
VFR CONDITIONS ARE FORECAST FOR THE NEXT 24 HOURS AT ALL SITES.
WINDS WILL BE BREEZY (10-15 KTS WITH HIGHER GUSTS) DURING THE
AFTERNOON AND EVENING HOURS, ESPECIALLY FRIDAY.
FIRE WEATHER
DRY CONDITIONS AND MOSTLY LOCALLY BREEZY WINDS WILL PERSIST
TODAY. A SYSTEM APPROACHING THE REGION WILL BRING WIDESPREAD
BREEZY WINDS TOMORROW THROUGH SATURDAY. THIS WILL LEAD TO
ELEVATED FIRE WEATHER CONCERNS IN THE WA COLUMBIA BASIN IN THE
AFTERNOON (30-50% CHANCE OF WIND/RH CRITERIA BEING MET). SHOWERS
AND ISOLATED THUNDERSTORMS WILL DEVELOP ALONG THE CASCADE CREST
TOMORROW THROUGH SATURDAY, WITH DRY CONDITIONS AND LIGHT WINDS
RETURNING SUNDAY. AN ACTIVE WEATHER PATTERN RETURNS NEXT WEEK.
PRELIMINARY POINT TEMPS/POPS
PDT 47 72 44 66 / 0 0 0 0
ALW 52 73 49 67 / 0 0 0 0
PSC 49 77 46 71 / 0 0 0 0
YKM 47 74 43 68 / 0 0 0 10
HRI 50 73 45 69 / 0 0 0 0
ELN 43 65 38 60 / 0 0 0 40
RDM 39 72 37 62 / 0 0 0 0
LGD 43 74 42 63 / 0 0 0 10
GCD 41 79 40 65 / 0 0 0 10
DLS 51 71 48 66 / 0 0 0 30
PDT WATCHES/WARNINGS/ADVISORIES
WA...NONE.
OR...NONE.
DISCUSSION...82
AVIATION...86
FIRE WEATHER...82
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