847
FXUS66 KPDT 191725
AFDPDT
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PENDLETON OR
1025 AM PDT MON OCT 19 2026
KEY MESSAGES
- PATTERN SHIFT AT THE BEGINNING OF THE WEEK WILL BRING
SEASONAL TEMPERATURES
- CHANCES OF PRECIPITATION AND THUNDERSTORMS WEDNESDAY AND
THURSDAY
DISCUSSION
CURRENT NIGHTTIME SATELLITE IS SHOWING MOSTLY CLOUDY SKIES OVER THE
REGION. THIS WILL KEEP OVERNIGHT TEMPERATURES A BIT WARMER THAN
PREVIOUS NIGHTS. NBM SHOWS OVERNIGHT LOWS TO BE IN THE LOW TO
MID 30S ALONG THE FOOTHILLS, THROUGH THE BASIN AND ADJACENT
VALLEYS, THE GORGE AND CENTRAL OR WITH A FEW ISOLATED LOCATIONS
SEEING LOW 40S. THE COLD PRONE AREAS AROUND THREE RIVERS AND
SENECA WILL SEE TEMPERATURES REMAIN BELOW FREEZING.
HI-RES MODELS SHOW A SOUTHWEST FLOW HAS SETTLED OVER THE REGION
AS THE UPPER LEVEL RIDGE MOVED EAST AND THE UPPER LEVEL LOW
MOVES DOWN THE COAST AND IS BY B.C. CURRENTLY. THIS FLOW REGIME
WILL KEEP THE REGION UNDER DRY CONDITIONS WITH NEAR NORMAL TO
SLIGHTLY ABOVE NORMAL TEMPERATURES. IN HOUSE CALCULATIONS SHOW
TEMPERATURES TO BE 2-6 DEGREES ABOVE SEASONAL NORMAL IN SOME
LOCATIONS ALONG THE FOOTHILLS OF THE BLUES, THE BASIN AND THE
GORGE. NBM SHOWS TEMPERATURES TO BE IN THE LOW TO MID 60S FOR
MUCH OF THE REGION WITH A FEW AREAS ALONG THE EASTERN MOUNTAINS
AND JOHN DAY BASIN SEEING LOW 70S THROUGH WEDNESDAY.
BY MONDAY MODELS SHOW THE UPPER LEVEL LOW TO BE SHIFTING SOUTH OFF
THE COAST OF OREGON AND BRINGING A SHARPER SOUTHWEST FLOW OVER THE
REGION. MODELS ARE IN FIRM AGREEMENT THAT A CLOSED LOW WILL FORM
AND TRAVERSE TOWARDS THE COAST OF CALIFORNIA AND STRETCH AS FAR
NORTH AS OREGON. CLUSTERS DIFFER SLIGHTLY IN THE AMPLITUDE OF THE
LOW, BUT ARE IN AGREEMENT WITH IT SHIFTING SOUTH AND UNDERCUTTING
THE REGION BY TUESDAY AND WEDNESDAY. THE VARIANCE IN THE AMPLITUDE
WILL DETERMINE THE AMOUNT OF RAINFALL EXPECTED AS MODELS SHOW THE
POTENTIAL FOR WRAP AROUND MOISTURE MAKING ITS WAY INTO THE REGION
FROM THE EAST. NBM RAW ENSEMBLES SHOW A LOW CHANCE (20%) OF
PRECIPITATION REACHING THE EASTERN PORTION OF THE CWA BY
WEDNESDAY NIGHT. HIGHEST CHANCES OF RAIN WILL BE THURSDAY AS
MODELS SHOW MORE MOISTURE INFLUX AVAILABLE. MANY OF THE RAW
ENSEMBLES SHOW THE TIMING OF THE PRECIPITATION TO BE AFTER 5 AM
THURSDAY WITH 40-50% PROBABILITIES OF WETTING RAIN (0.1-0.2
INCHES).
NOT ONLY WILL THE LEADING EDGE OF THE UPPER LEVEL LOW BRING
PRECIPITATION, BUT WARM AIR ADVECTION WILL BRING SOME INSTABILITY TO
THE REGION AS WELL AS EARLY AS WEDNESDAY NIGHT. NBM SHOWS THERE TO
BE A 15% CHANCE OF THUNDERS ALONG THE EASTERN MOUNTAINS AND 15-20%
CHANCES OF AFTERNOON THUNDERSTORMS THURSDAY.
AVIATION /18Z TAFS THROUGH 18Z TUESDAY/
VFR CONDITIONS AND PREDOMINANTLY LIGHT, DIURNALLY AND TERRAIN-
DRIVEN WINDS OF 10 KTS OR LESS ARE EXPECTED (95% CONFIDENCE OR
HIGHER) THROUGH THE PERIOD. THERE IS A LOW CHANCE (30% OR LESS)
OF LIGHT RAIN AT BDN/RDM THROUGH THIS EVENING, WITH EVEN LOWER
CHANCES (20% OR LESS) ELSEWHERE.
PRELIMINARY POINT TEMPS/POPS
PDT 62 36 63 36 / 0 0 0 0
ALW 63 41 64 43 / 0 0 0 0
PSC 65 36 68 36 / 0 0 0 0
YKM 63 40 70 40 / 0 0 0 0
HRI 63 36 66 35 / 0 0 0 0
ELN 60 36 67 38 / 0 0 0 0
RDM 59 29 62 27 / 10 10 0 0
LGD 69 36 70 39 / 0 0 0 0
GCD 71 38 72 40 / 0 0 0 0
DLS 66 44 71 42 / 10 10 0 0
PDT WATCHES/WARNINGS/ADVISORIES
WA...NONE.
OR...NONE.
DISCUSSION...90
AVIATION...86
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