632
FXUS66 KPDT 211313 CCA
AFDPDT
AREA FORECAST DISCUSSION...CORRECTED
NATIONAL WEATHER SERVICE PENDLETON OR
611 AM PDT FRI AUG 21 2026
KEY MESSAGES
- HOT TEMPERATURES TODAY -- HEAT ADVISORIES IN EFFECT.
- VERY LOW TO SLIGHT CHANCE (5-20 PERCENT) OF HIGH-BASED SHOWERS
AND THUNDERSTORMS TODAY AND SATURDAY.
- WIDESPREAD BREEZY TO WINDY WESTERLY WINDS COUPLED WITH LOW
RELATIVE HUMIDITY SATURDAY -- FIRE WEATHER WATCHES IN EFFECT.
DISCUSSION
AN UPPER 500 MB RIDGE CONTINUES TO DRIVE THE HOT WEATHER ACROSS
THE REGION FOR ANOTHER DAY AS TEMPERATURES TODAY ARE EXPECTED
TO BE THE HOTTEST OF THE WEEK. WIDESPREAD 90S WILL BE COMMON
WITH HOTTER 100 TO 105 DEGREE TEMPERATURES ACROSS THE COLUMBIA
BASIN REGION OF BENTON, FRANKLIN AND WALLA WALLA COUNTIES OF WA.
AN UPPER LOW OVER THE EASTERN PACIFIC WILL REACH THE OR/WA
COAST BY MIDDAY SATURDAY, PUSHING THE UPPER RIDGE EAST, COOLING
ALOFT AND CREATING CONDITIONS FOR SHOWER AND THUNDERSTORMS
ESPECIALLY ACROSS THE HIGHER TERRAIN MOUNTAINS ZONES. BY 12Z
SATURDAY SHOWERS AND THUNDERSTORM CHANCES INCREASE TO AROUND
5-15% OVER THE WA CASCADES AND TO 20% BY 18Z ACROSS BOTH THE WA
CASCADES AND THE EASTERN BLUE MOUNTAINS OF OR/WA. HEATRISK IS
IN THE 2 TO 3 CATEGORY TODAY WITH WIDESPREAD HEAT ADVISORIES IN
EFFECT AS TEMPERATURES RANGE FROM THE 90S TO THE LOW 100S ACROSS
THE FORECAST AREA.
AVIATION /12Z TAFS THROUGH 12Z SATURDAY/
VISIBILITY HAS BEEN IFR AT ALW AND IF IT FOLLOWS THE TREND S OF
THE LAST 24 HOURS, WILL NOT IMPROVE TO MVFR UNTIL ABOUT 10 AM.
AT LEAST SOME POTENTIAL FOR SMOKE TO CREATE HZ/FU AT THE OTHER
TERMINAL,K HOWEVER VISIBILITY WON’T BE AS LOW. NO CEILINGS ARE
EXPECTED AND LIGHT AND VARIABLE WINDS THOUGH THE TAF, 3EXPECT
FOR GUSTY WEST WINDS BY 06Z AT DLS. .
FIRE WEATHER
COMBINED PROBABILITIES FOR SPECIFIC WIND THRESHOLDS AND LOW
RELATIVE HUMIDITY DEVELOPS SATURDAY AFTERNOON, ACROSS THE
COLUMBIA BASIN OF WASHINGTON AND OREGON, THE YAKIMA VALLEY AND
CENTRAL OREGON. THE CRITICAL FIRE WEATHER CONDITIONS ARE
EXPECTED THROUGH MID EVENING SATURDAY AND FIRE WEATHER WATCHES ARE
IN EFFECT FOR OR696, OR698, AND OR700 OR691, OR703, WA690, AND
WA691. FIRE WEATHER RISK OWING TO LIGHTNING IS POSSIBLE ACROSS
THE WA695 ZONE WHERE ABOUT A 20% CHANCES FOR THUNDERSTORMS ALONG
THE WA CASCADES EASTERN SLOPES.
PRELIMINARY POINT TEMPS/POPS
PDT 96 63 90 54 / 0 10 10 0
ALW 101 70 93 61 / 0 10 10 0
PSC 100 66 95 56 / 0 10 10 0
YKM 98 70 95 57 / 0 10 20 0
HRI 97 68 92 57 / 0 10 10 0
ELN 96 67 88 54 / 0 10 30 0
RDM 93 54 88 44 / 0 10 0 0
LGD 101 65 95 54 / 0 10 20 10
GCD 100 63 95 54 / 0 10 10 10
DLS 96 66 85 59 / 10 10 10 0
PDT WATCHES/WARNINGS/ADVISORIES
WA...AIR QUALITY ALERT UNTIL 1 PM PDT THIS AFTERNOON FOR WAZ028>030.
HEAT ADVISORY UNTIL 10 PM PDT THIS EVENING FOR WAZ024-026>030-
521-523.
FIRE WEATHER WATCH FROM SATURDAY AFTERNOON THROUGH SATURDAY
EVENING FOR WAZ690-691.
FIRE WEATHER WATCH FROM THIS EVENING THROUGH SATURDAY
AFTERNOON FOR WAZ695.
OR...AIR QUALITY ALERT UNTIL 1 PM PDT THIS AFTERNOON FOR ORZ041-050-
502-505-506-509>511.
HEAT ADVISORY UNTIL 10 PM PDT THIS EVENING FOR ORZ041-044-049-
050-502-503-505>508-510-511.
FIRE WEATHER WATCH FROM SATURDAY AFTERNOON THROUGH SATURDAY
EVENING FOR ORZ691-696-698-700-703.
DISCUSSION...71
AVIATION...71
FIRE WEATHER...71
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