111
FXUS66 KPDT 190530
AFDPDT
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PENDLETON OR
1030 PM PDT WED MAR 18 2026
.UPDATED AVIATION DISCUSSION.
KEY MESSAGES
- UNSEASONABLY WARM TEMPERATURES THROUGH FRIDAY
- COOLER, MORE NORMAL TEMPERATURES BEYOND FRIDAY
- CONTINUED RAIN OVER THE WASHINGTON CASCADES WILL KEEP RIVERS
RUNNING HIGH.
DISCUSSION
VISIBLE SATELLITE IMAGERY SHOWED A BROKEN BAND OF CLOUD COVER
SPREADING ACROSS WASHINGTON WHILE INDICATIONS OF MORE MIDDLE
LAYER MOISTURE WAS EVIDENT WITH CLOUDS DEVELOPING OFF THE OREGON
CASCADES AND SPREADING INTO THE COLUMBIA BASIN. THE MOISTURE,
ASSOCIATED WITH A STALLED ATMOSPHERIC RIVER THAT WILL PERSIST
THROUGH AT LEAST THURSDAY. THE EASTERN SLOPES OF HE WASHINGTON
CASCADE CRESTS IS FORECAST TO RECEIVE ABOUT ANOTHER 2 TO 4
INCHES OF RAINFALL, GIVEN VERY HIGH SNOW LEVELS FROM 8 TO 9K FT
AGL THOUGH THIS WEEK. AS A RESULT, HYDROLOGIC IMPACTS INCLUDE
WITHIN BANK RISES FOR MOST OF THE TRIBUTARIES AND MAIN STEMS OF
YAKIMA AND NACHES WITH AT LEAST THE NACW1 HAVING A MINOR FLOOD
FORECAST BY LATE FRIDAY INTO SATURDAY. A FLOOD WATCH HAS BEEN
HOISTED FOR THE REACH OF THE NACHES RIVER AT NACHES.
DESPITE THE PRESENCE OF THE ATMOSPHERIC RIVER (MOSTLY
WASHINGTON COUNTIES) IS ANOMALOUSLY WARM TEMPERATURES THROUGH
THURSDAY WITH NBM FORECASTING EXPECTED HIGHS IN THE 70S FOR ALL
NON MOUNTAIN ZONES. BASIN AND RIVER VALLEYS, AND EVEN CENTRAL
OREGON CAN HIT AROUND 80. AS OF 1 PM TODAY, SEVERAL ODOT OBS IN
THE JOHN DAY BASIN HAVE HIT 77-78 DEGREES, AND 79 DEGREES WAS
OBSERVED AT THE BEND AND MADRAS AIRPORTS. IN FACT, HIGH
CONFIDENCE IN TEMPS AROUND 80 FOR THURSDAY IS SUPPORTED BY A
25TH TO 75TH PERCENTILE NBM ENS MEMBERS OF 80 TO 82F. LITTLE
MORE UNCERTAINTY EXISTS IN AREAS LIKE THE LOWER COLUMBIA BASIN
WHERE HERMISTON’S SIMILAR STATS ARE 75 TO 81F.
TRENDS FOR WINDS UPTICK ACROSS THE SIMCOE HIGHLANDS AND YAKIMA
VALLEY (PARTS OF KLICKITAT AND YAKIMA COUNTIES) ON THURSDAY
AFTERNOON FOLLOWED BY THE FRONTAL BOUNDARY LATE FRIDAY THAT WILL
NO DOUBT BRING IN STRONGER WESTERLY BOUNDARY LAYER MOMENTUM.
NBM MEAN SHOWS GUSTS AVERAGING FROM 30 TO 50 KNOTS ACROSS THE
SIMCOE HIGHLANDS. RUSSELL/71
AVIATION /06Z TAFS THROUGH 06Z FRIDAY/
VFR CONDITIONS CURRENTLY ACROSS ALL SITES, WHICH WILL STAY THE
COURSE THROUGH THE PERIOD. BREEZY WINDS ARE EXPECTED FOR
KPSC/KDLS/KRDM/KBDN THURSDAY AFTERNOON WITH GUSTS OF 20-25KTS.
ELSEWHERE, WINDS WILL HOVER AT OR BELOW 10KTS. 75
FIRE WEATHER
MUCH WARMER THAN NORMAL TEMPERATURES AS AS WELL AS DRY
CONDITIONS FOR THIS WEEK CONTINUE OVER PARTS OF CENTRAL OREGON.
WINDS IN THE AFTERNOON HAVE THE CAPABILITY TO GUST BETWEEN 20
AND 30 MPH, BY THE MEAN NBM VALUES. THIS COMBINATION OF STRONG
WINDS, LOW RELATIVE HUMIDITY, AND WARM TEMPERATURES CAN
CONTRIBUTE TO FIRE SPREAD. EXPECT A COLD FRONT TO SWEEP ACROSS
THE INTERIOR NORTHWEST LATE FRIDAY OR FRIDAY NIGHT, GIVING
RECOVER FROM LOW RH. GRASSES THAT HAVE NOT GREENED UP WILL
EXPERIENCE ELEVATED FIRE WEATHER RISK. ANY FIRE THAT DEVELOPS
CAN CATCH AND SPREAD QUICKLY. OUTDOOR BURNING IS NOT RECOMMENDED
EACH AFTERNOON THIS WEEK OVER CENTRAL OREGON INTO THE JOHN
DAY/OCHOCO HIGHLANDS. RUSSELL/71
PRELIMINARY POINT TEMPS/POPS
PDT 47 73 50 75 / 0 10 0 0
ALW 52 73 55 74 / 0 10 10 10
PSC 51 74 53 75 / 10 10 0 0
YKM 46 71 49 69 / 10 10 10 30
HRI 48 73 51 75 / 0 10 0 0
ELN 43 62 45 60 / 20 20 30 50
RDM 40 75 44 76 / 0 0 0 0
LGD 46 74 48 76 / 0 0 0 0
GCD 43 75 47 76 / 0 0 0 0
DLS 48 72 51 68 / 0 10 10 30
PDT WATCHES/WARNINGS/ADVISORIES
WA...NONE.
OR...NONE.
DISCUSSION...71
AVIATION...75
FIRE WEATHER...71
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