242
FXUS66 KPDT 081712
AFDPDT
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PENDLETON OR
1012 AM PDT FRI AUG 8 2025
UPDATED FOR AVIATION
AVIATION
18Z TAFS...VFR CONDITIONS ARE EXPECTED THROUGH THE WEEKEND. WINDS
WILL GENERALLY BE 10 KTS OR LESS, EXCEPT AT DLS, WHICH COULD SEE
SOME GUSTS TO AROUND 20 KTS LATE THIS AFTERNOON AND EVENING
BEFORE RETURNING TO 10 KTS OR LESS.
PREV DISCUSSION
/ISSUED 1036 PM PDT THU AUG 7 2025/
UPDATED AVIATION DISCUSSION.
AVIATION...06Z TAFS...VFR CONDITIONS CURRENTLY ACROSS ALL SITES,
WHICH WILL STAY THE COURSE THROUGH THE PERIOD. BREEZY WINDS
CURRENTLY EXPERIENCED AT KYKM, BUT WILL BE DISSIPATING OVERNIGHT.
BREEZY CONDITIONS WILL ALSO RETURN FOR KDLS LATE FRIDAY AFTERNOON,
BUT IS EXPECTED TO ONLY LAST A COUPLE HOURS DUE TO A BRIEFLY
TIGHTENING PRESSURE GRADIENT ALONG THE CASCADES. 75
PREV DISCUSSION... /ISSUED 150 PM PDT THU AUG 7 2025/
DISCUSSION...SATELLITE AND RADAR IMAGERY THIS AFTERNOON SHOWS
SCATTERED SHOWERS/THUNDERSTORMS DEVELOPING ACROSS THE WA COLUMBIA
BASIN AND ISOLATED CELLS DEVELOPING OVER THE HIGHER TERRAIN OF THE
NORTH EAST OR, INCLUDING THE GRANDE RONDE VALLEY. THESE STORMS
ARE THE RESULT OF AN UPPER TROUGH PASSING OVER THE PACNW TODAY,
WITH THUNDERSTORMS DEVELOPING UNDER FAVORABLE CONDITIONS, AS THE
EXIT REGION OF AN UPPER JET WRAPPING AROUND THE TROUGH IS
CURRENTLY CO-LOCATED OVER THESE STORMS.
THROUGH TONIGHT: THE UPPER TROUGH WILL CONTINUE TO MOVE ACROSS THE
PACNW TODAY, RESULTING IN SHOWERS AND THUNDERSTORMS TO CONTINUE TO
DEVELOP INTO THE EARLY EVENING HOURS. THUNDERSTORMS WILL BE AIDED
BY MODERATE TO STRONG LOW/MID LEVEL LAPSE RATES (LOW: ~10C/KM
MID: ~7C/KM), THE EXIT REGION OF AN UPPER LEVEL JET ALOFT, AND
MODEST INSTABILITY (500-750J/KG), WITH STORMS CAPABLE OF PRODUCING
GUSTY OUTFLOW WINDS AND SMALL HAIL. THIS ACTIVITY WILL MOSTLY BE
FOCUSED NORTH AND EAST OF THE FORECAST AREA, HOWEVER AREAS OF THE
NORTHERN BLUES, UNION/WALLOWA COUNTIES, AND PORTIONS OF THE WA
COLUMBIA BASIN. OTHERWISE, THE UPPER TROUGH PASSAGE WILL RESULT IN
BREEZY CONDITIONS THROUGH THE CASCADE GAPS INTO THE COLUMBIA
BASIN THROUGH THIS EVENING.
TOMORROW THROUGH MONDAY: GROWING CONFIDENCE (70-90%) THAT UPPER
LEVEL RIDGING WILL BUILD ACROSS THE NORTHEAST PACIFIC AND THE
PACNW THROUGH MONDAY. WHILE THE UPPER RIDGE WILL BE CENTERED WELL
OFFSHORE THE REGION, 500MB HEIGHTS WILL BE INCREASING THROUGH THIS
PERIOD, RESULTING IN WARMING TEMPERATURES AND DRIER CONDITIONS
OVERALL. THERE IS HIGH CONFIDENCE (70-85%) THAT THE LOWER
ELEVATIONS WILL SEE TEMPERATURES IN THE MID TO UPPER 90S, WHILE
THERE IS A 60-80% CHANCE THAT TEMPERATURES IN PORTIONS OF THE
COLUMBIA BASIN AROUND TRI-CITIES/HERMISTON, PORTIONS OF NORTH
CENTRAL OR, AND THE JOHN DAY BASIN REACH THE 100 DEGREE MARK
MONDAY AFTERNOON.
TUESDAY THROUGH THURSDAY: MODERATE CONFIDENCE (50-70%) THAT UPPER
LEVEL TROUGHING WILL DEVELOP ACROSS THE PACNW TUESDAY AS THE
OFFSHORE UPPER RIDGE RETROGRADES. HOWEVER, CONFIDENCE IN
STRENGTH/TIMING OF THE UPPER TROUGH ARE LOW-MOD (30-50%) THROUGH
THIS PERIOD, AS ENSEMBLE CLUSTER GUIDANCE SOLUTIONS DIFFER IN THE
TROUGH AXIS POSITION AND THE DEPTH OF THE TROUGH AS WELL.
REGARDLESS, EXPECTATION IS FOR TEMPERATURES TO COOL SLIGHTLY
DURING THIS PERIOD TO NEAR NORMAL VALUES, WHILE BREEZY WINDS
DEVELOP THROUGH THE CASCADE GAPS INTO THE COLUMBIA BASIN AND
CENTRAL OR (CONFIDENCE LOW, 30%, IN STRENGTH OF WINDS). LAWHORN/82
PRELIMINARY POINT TEMPS/POPS
PDT 83 55 88 58 / 0 0 0 0
ALW 83 61 88 64 / 0 0 0 0
PSC 86 57 91 60 / 0 0 0 0
YKM 86 58 91 62 / 0 0 0 0
HRI 86 58 90 60 / 0 0 0 0
ELN 84 58 87 61 / 0 0 0 0
RDM 84 47 88 51 / 0 0 0 0
LGD 81 52 86 54 / 0 0 0 0
GCD 83 50 87 53 / 0 0 0 0
DLS 86 62 90 66 / 0 0 0 0
PDT WATCHES/WARNINGS/ADVISORIES
OR...NONE.
WA...NONE.
SHORT TERM...82
LONG TERM....82
AVIATION...77
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