680
FXUS66 KPDT 150526
AFDPDT
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PENDLETON OR
1026 PM PDT WED OCT 14 2026
KEY MESSAGES
- ABOVE AVERAGE TEMPERATURES ACROSS THE REGION ON FRIDAY WITH BREEZY
CONDITIONS IN THE BLUE MOUNTAINS AND GRANDE RONDE VALLEY
- BREEZY CONDITIONS IN THE COLUMBIA RIVER GORGE AND KITTITAS
VALLEY ON SATURDAY
- CHANCES FOR RAIN EARLY NEXT WEEK.
DISCUSSION
THE WEATHER TODAY HAS BEEN GENERALLY QUIET WITH THE ONLY NOTE
BEING A BAND OF LIGHT RAIN THAT HAS BEEN MOVING THROUGH WESTERN
PORTIONS OF THE CWA. THAT BAND OF LIGHT RAIN HAS LARGELY
DISSIPATED AND VISIBLE SATELLITE IMAGERY SHOWS CLEAR TO MOSTLY
CLEAR SKIES MOVING INTO THE REGION FROM THE NORTH. MID-LEVEL
WATER VAPOR IMAGERY AND UPPER AIR SOUNDINGS SHOW THAT AN UPPER
LEVEL RIDGE HAS STARTED BUILDING INTO THE REGION.
LATEST MODEL GUIDANCE SHOWS THAT RIDGING WILL BE IN PLACE
THROUGH FRIDAY BEFORE A SHORTWAVE TROUGH COMES THROUGH THE
REGION. AS A RESULT, TEMPERATURES WILL INCREASE THROUGHOUT THE
WEEK, WITH THE HOTTEST DAY BEING ON FRIDAY WHERE TEMPERATURES
WILL LIKELY BE IN THE MID 70S TO LOW 80S FOR LOWER ELEVATIONS
AND IN THE LOW 60S TO LOW 70S IN HIGHER ELEVATIONS, WHICH IS
AROUND 10-20 DEGREES ABOVE NORMAL (90% CONFIDENCE). OF
ADDITIONAL NOTE, MODELS ARE STILL INDICATING THAT BREEZY
CONDITIONS WILL LIKELY SET UP IN THE BLUE MOUNTAINS AND THE
GRANDE RONDE VALLEY FRIDAY MORNING (CONFIDENCE 80%). THIS IS A
RESULT OF A SOMEWHAT LARGE PRESSURE GRADIENT SETTING UP IN THE
BLUE MOUNTAINS. THE SURFACE PRESSURE GRADIENT TOOL DEVELOPED BY
THE SPC SHOWS THAT THE NAM AND SREF HAVE A PRESSURE GRADIENT OF
4-7 MB BETWEEN BAKER CITY AND MEACHAM. THE MEAN WIND GUSTS OFF
THE REFS SHOWS WIND GUSTS UP TO 45-50 MPH IN THE BLUE MOUNTAINS
AND 35-40 MPH IN THE GRANDE RONDE VALLEY ON FRIDAY MORNING.
AFTER FRIDAY, MODEL GUIDANCE SHOWS THAT TWO SYSTEMS WILL COME
THROUGH THE REGION. THE FIRST IS A SHORTWAVE TROUGH THAT WILL
MOVE THROUGH THE NORTHWEST DURING THE DAY SATURDAY INTO SUNDAY
MORNING. CURRENTLY, RAIN ASSOCIATED WITH THE SYSTEM LOOKS
CONFINED TO THE HIGHER TERRAIN IN THE CASCADES. IN ADDITION, AS
THE SYSTEM COMES THROUGH, THE WINDS ON SATURDAY SHOULD SHIFT TO
BEING FROM THE SOUTHWEST. AS A RESULT, BREEZIER CONDITIONS WILL
LIKELY (80% CONFIDENCE) DEVELOP ON SATURDAY MAINLY IN AREAS
WITH CHANNELING EFFECTS (I.E. COLUMBIA RIVER GORGE AND KITTITAS
VALLEY). CURRENT NBM GUIDANCE SUGGESTS THAT THE WINDS WILL
REMAIN BELOW WIND ADVISORY CRITERIA (WIND GUSTS >45MPH) WITH A
PROBABILITY OF MEETING ADVISORY CRITERIA OF <10%.
THE SECOND TROUGH HAS MORE UNCERTAINTY WITH IT BUT MODELS BRING
IT THROUGH EARLY NEXT WEEK. THIS TROUGH LOOKS TO BE THE NEXT
BEST CHANCE OF RAIN. THE LATEST NBM SUGGESTS A 50% CHANCE OF
RECEIVING MEASURABLE RAIN (>0.01 IN) IN THE BLUE MOUNTAINS AND
A 0-25% CHANCE IN THE LOWER ELEVATIONS DURING THE DAY ON
TUESDAY. WITH THAT BEING SAID, THIS CHANCE FOR RAIN HAS DROPPED
SUBSTANTIALLY COMPARED TO A RUN OF THE NBM 24 HOURS AGO, WHICH
HAD PROBS OF 75% AND 25-50% CHANCE OF MEASURABLE RAIN FOR THE
HIGHER AND LOWER ELEVATIONS RESPECTIVELY. THIS CHANGE IS DUE TO
A LARGE SHIFT IN MANY OF THE MODELS WHICH CAUSES THE TROUGH TO
DIG FARTHER SOUTH AND FORM A CUTOFF OVER CALIFORNIA. HOWEVER,
THIS SYSTEM STILL HAS A LARGE AMOUNT OF UNCERTAINTY ASSOCIATED
WITH IT AS ILLUSTRATED BY THE LREF CLUSTERS. LREF CLUSTER EOF'S
SHOW THAT TIMING IS THE LEADING SOURCE OF UNCERTAINTY WITHIN
THE ENSEMBLE BUT THERE IS STILL SOME UNCERTAINTY REGARDING THE
AMPLITUDE OF THE TROUGH. SHOULD THE DEEPER TROUGH TREND
CONTINUE, MOST AREAS WOULD SEE LITTLE TO NO RAIN, WHILE IF THE
MODELS TREND BACK NORTH, THERE WILL BE A LARGER CHANCE FOR RAIN.
GARTY/26
AVIATION /06Z TAFS THROUGH 06Z FRIDAY/
VFR CONDITIONS ARE FORECASTED AT ALL TAF SITES THROUGH THIS
PERIOD. CLEAR SKIES AND LIGHT WINDS ABOUT 9 KTS OR LESS ARE
EXPECTED AT ALL SITES THROUGH THE PERIOD AS WELL. AMES/01/82
PRELIMINARY POINT TEMPS/POPS
PDT 64 36 68 37 / 0 0 0 0
ALW 65 41 69 41 / 0 0 0 0
PSC 67 34 71 36 / 0 0 0 0
YKM 65 39 70 41 / 0 0 0 0
HRI 66 36 70 38 / 0 0 0 0
ELN 62 35 67 37 / 0 0 0 0
RDM 66 27 69 30 / 0 0 0 0
LGD 63 31 68 34 / 0 0 0 0
GCD 64 33 70 37 / 0 0 0 0
DLS 70 41 74 45 / 0 0 0 0
PRELIMINARY POINT TEMPS/POPS
PDT 38 69 38 74 / 0 0 0 0
ALW 40 69 44 75 / 0 0 0 0
PSC 37 72 36 70 / 0 0 0 0
YKM 43 70 42 69 / 0 0 0 0
HRI 39 70 38 71 / 0 0 0 0
ELN 40 67 37 67 / 0 0 0 0
RDM 31 75 33 79 / 0 0 0 0
LGD 36 70 40 70 / 0 0 0 0
GCD 36 75 36 76 / 0 0 0 0
DLS 46 74 44 75 / 0 0 0 0
PDT WATCHES/WARNINGS/ADVISORIES
WA...NONE.
OR...NONE.
DISCUSSION...26/71
AVIATION...01/82
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