701  
FXUS66 KPDT 222331  
AFDPDT  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE PENDLETON OR  
431 PM PDT WED OCT 22 2025  
 
.UPDATED AVIATION.  
 
   
AVIATION...00Z TAFS  
VFR CONDITIONS PREVAIL FOR THE NEXT  
24-HOURS. DRY CONDITIONS WITH LIGHT WINDS OF <12 KNOTS EXPECTED,  
EXCEPT FOR DLS THAT HAVE GUSTS UP TO 30-35 KNOTS OVER THE NEXT  
COUPLE OF HOURS. NOT EXPECTING CIG OR VIS ISSUES GOING THROUGH THE  
TAF PERIOD.  
 
 
   
PREV DISCUSSION  
/ISSUED 312 PM PDT WED OCT 22 2025/  
 
DISCUSSION...A PREDOMINANTLY QUASI-ZONAL 500-HPA RIDGE IS  
FORECAST THROUGH THURSDAY NIGHT. THIS WILL LEAD TO MOSTLY NEAR- TO  
ABOVE-NORMAL AFTERNOON HIGH TEMPERATURES ACROSS THE FORECAST  
AREA. THE MAIN ITEMS TO NOTE DURING THE PERIOD ARE BREEZY SOUTH  
TO SOUTHEAST WINDS THROUGH THE GRANDE RONDE VALLEY THIS AFTERNOON  
AND A CHANCE (25-54%) OF LIGHT RAIN SHOWERS ALONG THE WASHINGTON  
CASCADE CREST THIS AFTERNOON AND EVENING AS A SHORTWAVE CLIPS THE  
PACIFIC NORTHWEST.  
 
A STRONGER 500-HPA TROUGH WILL LIKELY (>95% CHANCE) ARRIVE FRIDAY  
NIGHT THROUGH THE WEEKEND, WITH ENSEMBLE AND DETERMINISTIC  
GUIDANCE SUGGESTING MULTIPLE SHORTWAVES, AND PERHAPS SURFACE LOWS,  
ROTATING AROUND THE BASE OF THE PARENT TROUGH AFTER THE INITIAL  
COLD FRONTAL PASSAGE FRIDAY AFTERNOON THROUGH SATURDAY MORNING.  
 
CURRENTLY, HIGHEST CONFIDENCE IN ACTIVE WEATHER IS FRIDAY NIGHT  
THROUGH SUNDAY AFTERNOON, DURING WHICH TIME THE MOUNTAINS  
(CASCADES AND BLUES) GENERALLY HAVE PERSISTENT 55-95% POPS, WITH  
35-80% POPS FOR THE LOWER ELEVATIONS. SNOW LEVELS WILL DROP TO  
PASS LEVEL OVER THE WEEKEND, ESPECIALLY SUNDAY AS THE TROUGH MOVES  
ONSHORE. ADVISORY-LEVEL MOUNTAIN SNOWFALL LOOKS LIKE A DISTINCT  
POSSIBILITY. CURRENT PROBABILITIES OF EXCEEDING 6 INCHES OF SNOW  
FOR THE CASCADES RANGE FROM 40-90%, HIGHEST FOR PASSES AT OR ABOVE  
4500 FT, WHILE THE NORTHERN BLUE MOUNTAINS HAVE A LOWER 5-30%  
PROBABILITY OF 6 INCHES OR MORE OF SNOW FOR THE PASSES. AREAS FROM  
SOUTHERN BEND SOUTH THROUGH LA PINE HAVE A LOW (5-25%) CHANCE OF  
REACHING OR EXCEEDING 2 INCHES OF SNOW.  
 
ASIDE FROM PRECIPITATION CHANCES, BREEZY TO WINDY SOUTH TO WEST  
WINDS ARE ANTICIPATED WITH THE WEEKEND SYSTEM. WILL NOTE THERE IS  
SIGNIFICANT SPREAD AMONG ENSEMBLE NWP GUIDANCE WITH RESPECT TO  
MAGNITUDE OF SURFACE WINDS. MOREOVER, CURRENT GUIDANCE IS SHOWING  
35-55 KT 850-HPA WINDS WITH FRONTAL PASSAGE LATE FRIDAY AND AGAIN  
SATURDAY WITH AS AN OFFSHORE SURFACE LOW TRACKS NORTHEASTWARD INTO  
THE PACIFIC NORTHWEST. WHILE THERE IS A WHOLE LOT MORE THAT GOES  
INTO A WIND FORECAST THAN JUST LOOKING AT ONE PRESSURE LEVEL,  
850-HPA WINDS ARE OFTEN USED AS A PROXY FOR WHAT CAN MIX TO THE  
SURFACE. THE HIGH END OF THE AFOREMENTIONED RANGE WOULD LEAD TO A  
VERY WINDY SCENARIO, WHILE THE WEAKER END OF THE RANGE WOULD BE  
NOTHING NOTEWORTHY FOR OUR FORECAST AREA. ADDITIONALLY, THE NBM  
CURRENTLY PAINTS WIDESPREAD 20-70% PROBABILITIES OF ADVISORY-  
LEVEL WIND GUSTS (45 MPH OR GREATER) DURING THE PERIOD WITH A  
10-40% PROBABILITY OF REACHING WARNING-LEVEL WIND GUSTS (58 MPH  
OR GREATER) FOR WIND-PRONE PORTIONS OF SOUTH-CENTRAL WASHINGTON,  
CENTRAL AND NORTHEAST OREGON FOR THE LATE FRIDAY THROUGH SUNDAY  
TIMEFRAME.  
 
NOTABLY, PRIOR TO COLD FRONTAL PASSAGE, CONFIDENCE IS MEDIUM-HIGH  
(60-80%) IN A PERIOD OF LOW RH (15-25%) AND BREEZY TO WINDY  
SOUTHWEST WINDS (WIDESPREAD 15-25 MPH WITH GUSTS OF 25-35 MPH)  
LEADING TO INCREASED POTENTIAL FOR CRITICAL FIRE WEATHER  
CONDITIONS ACROSS FIRE WEATHER ZONES OR700, OR704, AND OR705  
DURING THE LATE MORNING THROUGH EARLY EVENING HOURS IN CENTRAL  
OREGON. LOCALLY STRONGER WINDS OF 25-35 MPH AND GUSTS OF 35-45 MPH  
ARE ALSO FORECAST.  
 
AVIATION...18Z TAFS...VFR CONDITIONS EXPECTED. LIGHT, TERRAIN-  
DRIVEN WINDS LESS THAN 10 KTS WILL PREVAIL ACROSS ALL SITES, WITH  
FEW-SCT MID-LEVEL CIGS ROLLING THROUGH THE REGION AS WELL. SOME  
CLEARING WILL TAKE PLACE THIS EVENING, BEFORE MID-LEVEL CIGS  
RETURN OVERNIGHT HEADING INTO THURSDAY. 74  
 
 
   
PRELIMINARY POINT TEMPS/POPS  
 
PDT 40 65 44 68 / 0 0 0 10  
ALW 45 64 47 67 / 0 0 0 10  
PSC 39 66 42 63 / 0 0 0 20  
YKM 39 63 42 63 / 0 10 0 60  
HRI 40 65 42 64 / 0 0 0 20  
ELN 37 60 37 56 / 0 10 10 70  
RDM 32 66 38 67 / 0 0 0 30  
LGD 36 65 41 66 / 0 0 0 10  
GCD 35 66 41 69 / 0 0 0 10  
DLS 47 66 47 64 / 10 10 0 70  
 
 
   
PDT WATCHES/WARNINGS/ADVISORIES  
 
OR...NONE.  
WA...NONE.  
 
 
 
 
SHORT TERM...86  
LONG TERM....86  
AVIATION...95  
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