036
FXUS66 KPDT 260517
AFDPDT
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PENDLETON OR
1017 PM PDT TUE AUG 25 2026
KEY MESSAGES
1. VERY LOW CHANCES OF SHOWERS AND THUNDERSTORMS THIS AFTERNOON AND
EVENING
2. TEMPERATURES TODAY AND WEDNESDAY WILL REMAIN ABOVE SEASONAL
NORMAL THROUGH WEDNESDAY
3. AN UPPER LEVEL LOW APPROACHING THE REGION WILL BRING INCREASED
WINDS WEDNESDAY INCREASING FIRE WEATHER CONCERNS.
DISCUSSION
CURRENT SATELLITE SHOWS A CUMULUS FIELD DEVELOPING OVER THE ELKHORNS
AND BLUES AS WELL AS OVER THE EAGLE CAPS DOWN INTO THE WALLOWA
VALLEY. GROUND OBSERVATIONS ARE SHOWING NO RAINFALL ASSOCIATED WITH
THESE CELLS AT THIS TIME.
NBM RAW ENSEMBLES SHOWS A 5-15% CHANCE OF THUNDERSTORMS AND SHOWERS
OVER THE EASTERN MOUNTAINS AND WALLOWAS THIS AFTERNOON AND THIS
EVENING. LOOKING AT RAP FORECAST SOUNDINGS, THERE IS BETWEEN 500-650
J/KG OF MUCAPE, LIS OF -2 TO -3, LAPSE RATES OF 9-10 C/KM AND BULK
SHEAR NEARING 15-20 KNOTS. THIS IS ENOUGH INSTABILITY AND LIFT THAT
WE CANNOT RULE OUT THE POSSIBILITY OF A SHOWER OR THUNDERSTORM
FORMING OVER THE AREA. WEDNESDAY MODELS AND NBM RAW ENSEMBLES SHOW A
BIT MORE INSTABILITY IN THE REGION DECREASING THE CHANCES OF SHOWERS
AND THUNDERSTORMS TO UNDER 10%.
MODELS SHOW THE RIDGE OF HIGH PRESSURE REMAINING OVER THE REGION
THROUGH WEDNESDAY AHEAD OF THE NEXT SYSTEM. LOOKING AT IN HOUSE
CALCULATIONS, TEMPERATURES ARE EXPECTED TO BE ANYWHERE FROM 5 TO 10
DEGREES ABOVE SEASONAL AVERAGE TODAY, INCREASING TO NEAR 15 DEGREES
TODAY AND WEDNESDAY. LOOKING AT HEATRISK PROBABILITIES, TOMORROW
(WEDNESDAY) WILL BE THE PEAK WITH 70-80% PROBABILITIES OF AREAS
REACHING MODERATE HEATRISK (LEVEL 2 OF 4) ACROSS THE COLUMBIA BASIN
AND CENTRAL OR. THERE IS ALSO A LOW TO MEDIUM RISK OF AREAS IN THE
COLUMBIA BASIN SEEING MAJOR HEATRISK (LEVEL 3 OF 4) WITH 20-40%
PROBABILITIES. MODERATE HEATRISK AFFECTS THOSE WHO ARE SENSITIVE TO
HEAT, ESPECIALLY THOSE WITHOUT COOLING/HYDRATION, WHILE MAJOR
HEATRISK AFFECTS ANYONE WITHOUT COOLING/HYDRATION.
MODELS ON WEDNESDAY SHOW THE LEADING EDGE OF THE UPPER LEVEL LOW
BEGINNING TO MAKE ITS WAY ONSHORE. AS THE LOW BEGINS TO TRAVERSE
EAST, THE LEADING EDGE OVER THE CASCADES WEDNESDAY WILL BRING A
TIGHTENING OF THE SURFACE PRESSURE GRADIENTS. WINDS WILL BE
INCREASED THROUGH THE COLUMBIA RIVER GORGE, KITTITAS VALLEY AND
ALONG PORTION OF THE SIMCOE HIGHLANDS AND FOOTHILLS OF THE SOUTHERN
BLUES. NBM RAW ENSEMBLES SHOWS 70-80% PROBABILITIES THAT WINDS WILL
BE 20-25 MPH WITH GUSTS TO NEAR 30-35 MPH. THE INCREASE IN THE WINDS
WILL ALSO RAISE SOME FIRE WEATHER CONCERNS ON WEDNESDAY. WITH THAT,
A SPECIAL WEATHER STATEMENT HAS BEEN ISSUED FOR ISOLATED AREAS
WITHIN THE AFOREMENTIONED PLACES FOR CRITICAL FIRE WEATHER BETWEEN
1100-2000 (8PM) WEDNESDAY DUE TO WINDS AND LOW RELATIVE HUMIDITY.
WHILE NOT WIDESPREAD, THIS WILL AFFECT A FEW OF THE FIRES ALREADY ON
THE LANDSCAPE AS WELL AS ANY NEW FIRE THAT MAY OCCUR IN THESE
AREAS.
AVIATION /06Z TAFS THROUGH 06Z THURSDAY/
LOW CONFIDENCE ( ABOUT 10%) STILL EXISTS WITH RESPECT TO ANY
IMPACTS TO VISIBILITY DUE TO SMOKE. PREVAILING VFR AT ALL
TERMINALS WITH GUSTS IN THE THE GAP AREAS. DLS WILL REMAIN GUSTY
TO AROUND 25 KNOTS FOR THE ENTIRE TAF PERIOD. RDM/BDN SHOULD SEE
20 KNOTS GUSTS IN THE AFTERNOON AND YKM STARTING BY AROUND NOON.
LAMP GUIDANCE SUGGESTS LIGHT WINDS ELSEWHERE.
FIRE WEATHER
HOT AND DRY CONDITIONS WILL PREVAIL THROUGH WEDNESDAY WITH
ELEVATED FIRE WEATHER CONCERNS. WEDNESDAY WILL SEE AN INCREASE
IN WINDS AS AN UPPER LEVEL LOW MAKES ITS WAY ONSHORE. SUSTAINED
WINDS WILL BE BETWEEN 20-25 MPH WITH WINDS GUSTS BETWEEN 30-35
MPH. COUPLED WITH AREAS OF LOW RELATIVE HUMIDITY, A SPECIAL
WEATHER STATEMENT HAS BEEN ISSUED BETWEEN 1100-2000 (8PM)
WEDNESDAY FOR LOCALIZED CRITICAL FIRE WEATHER CONCERNS. WHILE
NOT WIDESPREAD, THIS WILL AFFECT A FEW OF THE FIRES ALREADY ON
THE LANDSCAPE AS WELL AS ANY NEW FIRE THAT MAY OCCUR IN THESE
AREAS.
PRELIMINARY POINT TEMPS/POPS
PDT 57 92 57 84 / 0 0 0 0
ALW 65 94 64 87 / 0 0 0 0
PSC 62 96 61 89 / 0 0 0 0
YKM 63 95 60 88 / 0 0 0 0
HRI 64 94 61 86 / 0 0 0 0
ELN 61 91 56 80 / 0 0 0 0
RDM 51 91 48 84 / 0 0 0 0
LGD 58 97 57 90 / 0 10 0 0
GCD 58 96 57 92 / 0 0 0 0
DLS 65 89 62 82 / 0 0 0 0
PDT WATCHES/WARNINGS/ADVISORIES
WA...AIR QUALITY ALERT UNTIL NOON PDT WEDNESDAY FOR WAZ026-028>030-
522-523.
OR...AIR QUALITY ALERT UNTIL NOON PDT WEDNESDAY FOR ORZ044-502-503-
507.
DISCUSSION...90
AVIATION...71
FIRE WEATHER...90
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