795
FXUS66 KPDT 211151
AFDPDT
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PENDLETON OR
451 AM PDT SUN JUN 21 2026
KEY MESSAGES
- HEAT RISK THREAT BUILDS-UP MONDAY THROUGH WEDNESDAY AS A RIDGE
PUSHES IN THE AREA.
- ELEVATED FIRE WEATHER CONDITIONS CONTINUE THROUGH THE WEEK
WITH DRY AIR LINGERING AND LOCALLY BREEZY WINDS DEVELOPING.
- WETTER PATTERN POSSIBLE BY THE END OF THE WEEK, BRINGING
RELIEF FROM THE HEAT.
DISCUSSION
TODAY: SATELLITE AND RADAR BOTH INDICATE DRY CONDITIONS
PREVAILING THROUGH THE REGION AS A WEAK SHORTWAVE PUSHES OUT OF
THE REGION AND A RIDGE BEGINS TO MOVE IN. AS THE SHORTWAVE PUSHES OFF,
PRESSURE GRADIENTS WILL NOT BE AS TIGHT COMPARED TO YESTERDAY
AND THUS WINDS WILL NOT BE AS BREEZY TODAY AS THEY WERE
YESTERDAY. HIGH TEMPS ACROSS THE LOWER ELEVATION WILL BE
SLIGHTLY COOLER COMPARED TO YESTERDAY WITH TEMPERATURES REACHING
THE MID TO UPPER 80S, WITH ISOLATED AREAS REACHING THE LOW 90S
(50-70% CHANCE). CLEAR CONDITIONS WILL PERSIST WITH AN ABUNDANCE
OF DRY AIR IN THE MID-LEVEL, KEEPING THINGS DRY.
MONDAY THROUGH WEDNESDAY: GUIDANCE IS IN GREAT AGREEMENT THAT
THE RIDGE SITUATED JUST OFF-SHORE WILL CONTINUE TO PUSH INTO THE
AREA WITH THE RIDGE AXIS OVER THE AREA SOMETIME LATE MONDAY
NIGHT TO TUESDAY MORNING, PERSISTING THROUGH WEDNESDAY MORNING.
A WARMING TREND AS A RESULT WILL LAST THROUGH THE MID-WEEK WITH
THE HOTTEST DAYS LOOKING TO BE TUESDAY AND WEDNESDAY. HIGH
TEMPERATURES HAVE SLIGHTLY DOWNTRENDED AGAIN OVER THE LAST
24-HOURS, WITH NBM ADVERTISING HIGH TEMPERATURES FROM 94-98 IN
THE COLUMBIA BASIN, 92-97 IN THE FOOTHILLS, AND 89-93 IN CENTRAL
OREGON. NBM V5.0 HAS ALL BUT ELIMINATED THE POSSIBILITY OF
TRIPLE DIGITS ON TUESDAY WITH ISOLATED POCKETS IN THE COLUMBIA
BASIN REACHING 0-5%, WITH WEDNESDAY LOOKING SLIGHTLY HIGHER AT
0-10%. FOR REFERENCE, SOME AREAS IN THE REGION WERE ADVERTISING
VALUES UP-TO 20% FOR TRIPLE DIGITS TO OCCUR. REGARDLESS,
WIDESPREAD MODERATE HEAT RISK WILL DEVELOP TUESDAY AND WEDNESDAY
(70-90% CHANCE). THE DALLES HAS A MODERATE TO HIGH CONFIDENCE
(60-80% CHANCE) OF MAJOR HEAT RISK (VALUE OF '3') ON TUESDAY,
THUS A HEAT ADVISORY HAS BEEN ISSUED.
THURSDAY: CRITICAL FIRE WEATHER CONDITIONS ARE POSSIBLE WITH
RELATIVE HUMIDITIES IN THE 9-14% RANGE AND DEVELOPING BREEZY
WINDS WITH AN ONCOMING TROUGH OCCUR. PRESSURE GRADIENTS WILL
TIGHTEN AS A TROUGH MOVES IN THE AREA, BUT WILL NOT BENEFIT FROM
THE MORE MOIST AIR UNTIL WIDESPREAD BREEZY WINDS OCCUR (40-60%
CHANCE). GIVEN THIS, THURSDAY WILL NEED TO BE MONITORED FOR
POTENTIAL CRITICAL FIRE WEATHER CONDITIONS FOR ALL DECLARED
ZONES.
FRIDAY THROUGH THE WEEKEND: GUIDANCE IS HINTING OF SLIGHTLY
UNSETTLED WEATHER TO MOVE BACK IN THE PICTURE BY THE WEEKEND,
INCREASING CHANCES OF RAIN IN THE MOUNTAIN RANGES (CONFIDENCE:
40-60% CHANCE). A RELIEF FROM THE HEAT AND DRY AIR FROM THE
ONCOMING MOISTURE TRANSPORTATION WILL BE POSSIBLE WITH THE
WEATHER SYSTEM.
AVIATION /12Z TAFS THROUGH 12Z MONDAY/
VFR CONDITIONS PREVAIL WITH LIGHT AND VARIABLE WINDS THROUGH THE
REST OF THE TAF PERIOD. NO CIG OR VIS ISSUES EXPECTED.
PRELIMINARY POINT TEMPS/POPS
PDT 84 52 88 53 / 0 0 0 0
ALW 85 58 89 58 / 0 0 0 0
PSC 89 56 92 57 / 0 0 0 0
YKM 88 57 90 60 / 0 0 0 0
HRI 87 55 91 56 / 0 0 0 0
ELN 84 54 87 57 / 0 0 0 0
RDM 83 45 88 52 / 0 0 0 0
LGD 81 48 85 50 / 0 0 0 0
GCD 84 45 89 49 / 0 0 0 0
DLS 88 59 93 64 / 0 0 0 0
PDT WATCHES/WARNINGS/ADVISORIES
WA...HEAT ADVISORY FROM 11 AM MONDAY TO 11 PM PDT TUESDAY FOR
WAZ024.
OR...HEAT ADVISORY FROM 11 AM MONDAY TO 11 PM PDT TUESDAY FOR
ORZ041.
DISCUSSION...95
AVIATION...95
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