143
FXUS66 KPDT 241736
AFDPDT
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PENDLETON OR
1036 AM PDT SUN MAY 24 2026
.UPDATED AVIATION DISCUSSION.
KEY MESSAGES
- WARM, DRY CONDITIONS TODAY
- A LOW-PRESSURE SYSTEM AND COLD FRONT ARE SLATED TO ARRIVE
MONDAY AFTERNOON AND EVENING, USHERING IN WIDESPREAD BREEZY TO
WINDY WESTERLY WINDS AND A SLIGHT CHANCE OF THUNDERSTORMS
- SHOWER AND THUNDERSTORM CHANCES CONTINUE TUESDAY THROUGH THE
WEEK, BUT UNCERTAINTY REMAINS IN FORECAST DETAILS
DISCUSSION
ABOVE-NORMAL TEMPERATURES AND DRY CONDITIONS WILL
CONTINUE TODAY AS THE REGION REMAINS UNDER ZONAL FLOW ALOFT.
LOCALLY BREEZY WINDS COUPLED WITH WIDESPREAD LOW AFTERNOON
RELATIVE HUMIDITY WILL LEAD TO LOCALLY ELEVATED FIRE WEATHER
CONCERNS, BUT NO HEADLINES ARE IN EFFECT.
THE NEXT FEATURE THAT WILL DRIVE OUR WEATHER MONDAY THROUGH THE
REMAINDER OF THE WEEK, A DEEPENING CLOSED LOW, IS VISIBLE IN
WATER VAPOR IMAGERY, LOCATED OFFSHORE IN THE VICINITY OF THE
GULF OF ALASKA. ENSEMBLE NWP GUIDANCE IS UNANIMOUS IN TAKING THE
CLOSED LOW SOUTHEAST ALONG THE PACIFIC COAST INTO MONDAY.
ENSEMBLE SOLUTIONS EXHIBIT SOME SUBTLE DIFFERENCES WITH REGARD
TO TIMING AND LOCATION/TRACK AS IT BEGINS TO MOVE ONSHORE
MONDAY, BUT CONFIDENCE IN THE LOW AND ITS ATTENDANT SURFACE COLD
FRONT PROVIDING A PATTERN CHANGE LATE MONDAY IS VERY HIGH (99
PERCENT).
MONDAY, FLOW ALOFT WILL TURN SOUTHWESTERLY, AND WIDESPREAD
BREEZY WINDS COUPLED WITH LOW RELATIVE HUMIDITY ARE FORECAST
ACROSS CENTRAL OREGON AND THE EASTERN MOUNTAINS PRIOR TO THE
ARRIVAL OF THE COLD FRONT MENTIONED IN THE PREVIOUS PARAGRAPH.
THIS WILL LEAD TO SOME ELEVATED FIRE WEATHER CONCERNS, BUT NONE
OF OUR FIRE WEATHER ZONES HAVE BEEN DECLARED READY FOR RED FLAG
WARNINGS YET SO NO HEADLINES ARE CURRENTLY PLANNED. TEMPERATURES
WILL BE WELL ABOVE NORMAL FOR THE AFOREMENTIONED REGION AS WELL
AS PORTIONS OF THE COLUMBIA BASIN AND BLUE MOUNTAIN FOOTHILLS.
BY LATE MONDAY, THE UPPER LOW AND ATTENDANT SURFACE COLD FRONT
ARE SLATED TO ARRIVE, WITH THE FRONT SWEEPING FROM WEST TO EAST
FROM AFTERNOON THROUGH LATE EVENING. NBM PROBABILITIES OF
EXCEEDANCE SUGGEST MEDIUM-HIGH CHANCES (40-85 PERCENT) OF
REACHING OR EXCEEDING ADVISORY-LEVEL WIND GUSTS ACROSS ALL OF
OUR NON-MOUNTAIN ZONES. MOREOVER, THE NBM IS ADVERTISING A CHANCE
(LOCALLY 30-60 PERCENT) OF EXCEEDING WARNING-LEVEL GUSTS (58 MPH
OR GREATER) ACROSS WIND-PRONE PORTIONS OF THE BLUE MOUNTAIN
FOOTHILLS AS WELL AS CENTRAL OREGON, THE SIMCOE HIGHLANDS, THE
YAKIMA VALLEY, AND THE EASTERN COLUMBIA RIVER GORGE. THINK THE
LATTER PROBABILITIES ARE TOO HIGH RELATIVE TO WHAT RAW GUIDANCE
IS SHOWING; NONETHELESS, WIND HEADLINES MAY BE NEEDED.
IN ADDITION TO THE STRONG, GUSTY WINDS MONDAY AFTERNOON AND
EVENING, THERE IS A LOW (5-15 PERCENT) CHANCE OF HIGH-BASED
SHOWERS AND THUNDERSTORMS ACROSS THE COLUMBIA BASIN, BLUE
MOUNTAIN FOOTHILLS, AND BLUE MOUNTAINS (MAINLY THE NORTHERN
BLUES). ALL DETERMINISTIC GUIDANCE IS HIGHLIGHTING SOME ELEVATED
INSTABILITY, AND SYNOPTIC-SCALE FORCING APPEARS TO BE SUPPORTIVE
OF KICKING OFF SOME SHOWERS OR THUNDERSTORMS GIVEN A SUFFICIENT
MID-LEVEL MOISTURE FIELD. THE NBM HAS YET TO INCLUDE A MENTION
OF THESE SHOWERS AND THUNDERSTORMS IN THE FORECAST PRIOR TO 5PM
PDT MONDAY, BUT DOES INCLUDE SHOWERS ACROSS THE REGION AFTER 5PM
AS THE FRONT MOVES THROUGH.
TUESDAY THROUGH THE REMAINDER OF THE WEEK, SHOWER AND
THUNDERSTORM CHANCES WILL CONTINUE, TIED TO THE LOCATION OF THE
UPPER-LEVEL LOW AS IT TRACKS INLAND ACROSS THE GREAT BASIN
(LIKELY TUESDAY THROUGH THURSDAY) AND EVENTUALLY EJECTS NORTH-
NORTHEAST ACROSS THE GREAT BASIN, PACIFIC NORTHWEST, OR ROCKIES
BY FRIDAY AND SATURDAY. ENSEMBLE CLUSTER ANALYSIS SUGGESTS A
PRETTY EVEN SPLIT (40-60 PERCENT, VARYING BY DAY) REGARDING THE
LOW BEING IN A LOCATION SUPPORTIVE (OR ALONG A SUPPORTIVE TRACK)
FOR SHOWERS, THUNDERSTORMS, AND NOTABLE SPRING PRECIPITATION
FOR THE FORECAST AREA.
AVIATION /18Z TAFS THROUGH 18Z MONDAY/
VFR CONDITIONS CURRENTLY AT ALL SITES, WHICH WILL STAY THE
COURSE THROUGH THE PERIOD. BREEZY WINDS OF 15-25KTS ARE
OCCURRING AT KDLS, WHICH WILL EXTEND TO INCLUDE KPDT/KPSC THIS
AFTERNOON AND KRDM/KBDN LATER THIS EVENING AS A WEAK COLD FRONT
PASSES. A FEW CLOUDS AT 25KFT TODAY, BUT MORE SCT-BKN CEILINGS
OF 25KFT ARE EXPECTED TOWARD THE END OF THE PERIOD ASSOCIATED
WITH A MORE SUBSTANTIAL COLD FRONT. 75
PRELIMINARY POINT TEMPS/POPS
PDT 82 51 82 43 / 0 0 0 70
ALW 82 56 84 48 / 0 0 0 60
PSC 86 54 86 45 / 0 0 0 60
YKM 85 52 78 44 / 0 0 0 30
HRI 84 53 83 44 / 0 0 0 60
ELN 77 47 73 40 / 0 0 0 30
RDM 84 45 81 34 / 0 0 0 30
LGD 82 47 86 42 / 0 0 10 70
GCD 84 46 87 39 / 0 0 0 90
DLS 83 54 77 46 / 0 0 0 30
PDT WATCHES/WARNINGS/ADVISORIES
WA...WIND ADVISORY FROM 11 AM TO 11 PM PDT MONDAY FOR WAZ027-521.
OR...WIND ADVISORY FROM 11 AM TO 11 PM PDT MONDAY FOR ORZ510-511.
DISCUSSION...86
AVIATION...75
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