045
FXUS66 KPDT 172256
AFDPDT
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PENDLETON OR
256 PM PST MON NOV 17 2025
DISCUSSION
DRY CONDITIONS WILL CONTINUE COUPLED WITH LOW
CEILING DECKS OF 500 TO 1000 FEET AND VISIBILITIES LESS THAN 5 SM
IN MANY AREAS. SLIGHT CHANCES OF MOUNTAIN SNOW AND MOUNTAIN
RAIN/SNOW MIX CONTINUE THROUGH THE NEXT COUPLE OF DAYS AS A
SHORTWAVE CONTINUES TO CROSS WASHINGTON STATE THROUGH TUESDAY. NOT
EXPECTING MUCH STRONG WINDS TO DEVELOP AS HIGH PRESSURE STARTS TO
SET-UP, LEAVING MOST WINDS TO BE LIGHT AND VARIABLE IN MOST
PLACES. AS THE SHORTWAVE PASSES OVER, A RIDGE WILL BEGIN TO ENTER
THE REGION GOING THROUGH WEDNESDAY, GIVING US GOOD CLEARING.
CLEARER SKIES AND LIGHT WINDS WILL LEAVE COLDER TEMPERATURES TO
ENTER THE REGION, WITH MUCH OF THE AREA BELOW FREEZING TUESDAY
EVENING INTO WEDNESDAY MORNING. FREEZE WARNINGS WERE WARRANTED FOR
OREGON SIDE OF THE GORGE WITH AMPLE EFFICIENT RADIATIVE COOLING
TO ALLOW MUCH COLDER TEMPERATURES. HAVEN'T BEEN ABLE TO GET GOOD
CONFIDENCE FOR THE WASHINGTON SIDE OF THE GORGE, BUT WILL PROBABLY
RE-VISIT LATER TONIGHT WITH NEW GUIDANCE TO DETERMINE IF ITS
NECESSARY BUT FREEZING CHANCES FOR THE WA GORGE ARE 30-50 PERCENT.
GOING FORWARD, THE RIDGE WILL MOVE OUT OF THE AREA BY THURSDAY
MORNING, ALLOWING ANOTHER SHORTWAVE TO DOMINATE THE SYNOPTIC
PATTERN. A CUT OFF LOW WILL DEVELOP INTO CALIFORNIA ALLOWING UPPER
EASTERN WINDS TO FORM WITH THE UPPER PATTERN TRANSITIONING INTO A
MORE ZONAL PATTERN. ADDITIONAL PRECIPITATION WILL DEVELOP WITH MOST
OF THE ACTIVITY WILL BE SECLUDED TO THE MOUNTAINS IN THE FORM OF
MOUNTAIN SNOW SHOWERS THROUGH THE WEEKEND WITH ANY PRECIP CHANCES
IN THE BASIN TAPERED TO SLIGHT CHANCES (15-25 PERCENT CHANCES).
ZONAL FLOW WILL CONTINUE THROUGH THE WEEKEND BEFORE ANOTHER
SHORTWAVE BRINGS ANOTHER WEATHER MAKER SOMETIME MONDAY, BRINGING A
WIDESPREAD WET PATTERN WITH VALLEY RAIN AND MOUNTAIN SNOW SHOWERS
TO OCCUR. WINDS WILL GENERALLY BE WEAK WITH BREEZY CONDITIONS NOT
BEING WIDESPREAD. NO ADDITIONAL HIGHLIGHTS OTHER THAN THE FREEZE
WARNING THROUGH TUESDAY NIGHT THRU WEDNESDAY MORNING WITH THE
POSSIBLE ADDITION OF THE WA SIDE OF THE GORGE.
AVIATION...00Z TAFS
A SURFACE TROUGH AND WEAK COLD FRONTAL
SYSTEM WILL BE THE WEATHER DRIVERS FOR THIS TAF PERIOD. SOME
LOCALIZED FOG AND AREAS OF LOWER STRATUS DEVELOPMENT OVERNIGHT IS
POSSIBLE. THE HREF PROBABILISTIC MODEL FIELDS HONE IN ON THE
FOOTHILLS OF THE NORTHERN BLUES, WHICH COULD IMPACT THE PSC AND TO
A LESSER DEGREE THE PDT TERMINALS. ADDITIONAL THE BND TERMINAL IN
ON THE NORTHERN PERIPHERY OF ANOTHER MODEL SIGNAL FOR REDUCED
VISIBILITY AND/OR CEILINGS OVERNIGHT (BUT MORE LIKELY IN THE
VICINITY THAN LONG MULTIPLE HOURLY IMPACTS). A FEW GUSTS THIS
EVENING TO AROUND 20 KNOTS MIGHT BE EXPECTED AT KDLS, HOWEVER THE
REST OF THE FORECAST IS LIGHT (UNDER 10 KT) WESTERLY WINDS BEHIND
THE FRONT INTO TUESDAY.
PRELIMINARY POINT TEMPS/POPS
PDT 36 48 30 47 / 20 10 0 0
ALW 39 48 33 47 / 30 20 10 0
PSC 36 52 30 48 / 20 10 0 0
YKM 32 50 29 48 / 30 10 0 0
HRI 36 50 30 47 / 20 10 0 0
ELN 32 47 27 45 / 50 10 0 0
RDM 29 48 20 50 / 10 0 0 0
LGD 38 50 27 51 / 30 20 20 0
GCD 35 50 29 54 / 10 10 10 0
DLS 39 52 34 50 / 20 10 0 0
PDT WATCHES/WARNINGS/ADVISORIES
OR...FREEZE WARNING FROM 11 PM TUESDAY TO 10 AM PST WEDNESDAY FOR
ORZ041.
WA...NONE.
SHORT TERM...95
LONG TERM....95
AVIATION...71
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