614  
FXUS66 KPDT 150247  
AFDPDT  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE PENDLETON OR  
747 PM PDT SUN AUG 14 2022  
   
EVENING UPDATE
 
THE PREVIOUS FORECAST REMAINS ON TRACK WITH  
LITTLE TO NO CHANGES NEEDED THIS EVENING. BROAD WEST-SOUTHWEST  
FLOW ALOFT REMAINS IN PLACE ACROSS THE PACIFIC NORTHWEST WHILE AN  
AREA OF HIGH PRESSURE SLOWLY RETROGRADES WESTWARD AND AMPLIFIES  
OVER UTAH/NEVADA MONDAY AND TUESDAY, RESULTING IN INCREASING  
HEIGHTS LOCALLY. EXPECT DRY CONDITIONS TO PERSIST HOWEVER  
TEMPERATURES WILL RISE INTO THE MIDWEEK, PEAKING IN THE TRIPLE  
DIGITS FOR MUCH OF THE COLUMBIA BASIN BY WEDNESDAY. BEYOND THE HOT  
WEATHER WE’LL HAVE TO KEEP AN EYE ON SOME MID-LEVEL MONSOONAL  
MOISTURE AND INSTABILITY MOVING IN FROM THE SOUTH WEDNESDAY  
AFTERNOON THROUGH THE END OF THE WEEK. WHILE MODEL AGREEMENT AND  
CONFIDENCE IN CONVECTIVE ACTIVITY IS FAIRLY LOW AT THIS POINT, IT  
COULD RESULT IN THE RETURN OF THUNDERSTORMS TO SPOTS LIKE CENTRAL  
OREGON AND THE CENTRAL/SOUTHERN BLUE MTNS, THUS ELEVATING FIRE  
WEATHER CONCERNS. 99  
 

 
   
PREV DISCUSSION
 
/ISSUED 440 PM PDT SUN AUG 14 2022/  
 
SHORT TERM...TONIGHT THROUGH TUESDAY NIGHT...BENIGN WEATHER,  
EXCEPT FOR INCREASING TEMPERATURES THROUGH MID WEEK, WILL  
PERSIST. BY WEDNESDAY, HIGH TEMPERATURES WILL BE IN THE UPPER 90S  
OVER THE RIDGES IN THE LOWER COLUMBIA BASIN TO NEAR 105 IN THE  
HANFORD AREA. ELSEWHERE, CONDITIONS WILL ALSO BE GRADUALLY HEATING  
UP AGAIN. THE FORECAST AREA IS UNDER A MORE ZONAL TO SOUTHWEST  
FLOW ALOFT TODAY. THE ATMOSPHERE IS DRY AND STABLE. IT IS SO  
STABLE THAT EVEN THE MOUNTAINS ARE FREE FROM ANY CUMULUS CLOUDS SO  
FAR THIS AFTERNOON. WILL LIKELY NEED AN EXCESSIVE HEAT WATCH OR A  
HEAT ADVISORY ISSUED BY MONDAY.  
 
ANOTHER CONCERN WILL BE THE POTENTIAL FOR CRITICAL FIRE WEATHER  
CONDITIONS, ESPECIALLY IN CENTRAL OR AND THE EASTERN/NORTHEAST  
MOUNTAINS, INCLUDING THE WA BLUE MOUNTAINS BY MIDWEEK. THIS IS DUE  
TO THE INCREASING CHANCES OF THUNDERSTORMS WITH ABUNDANT  
LIGHTNING DUE TO SOME MONSOONAL MOISTURE AND INSTABILITY WORKING  
ITS WAY NORTHWARD INTO THE FORECAST AREA BY WEDNESDAY. THIS  
COMBINED WITH THE HOT TEMPERATURES, STEEP LAPSE RATES AND  
INCREASING INSTABILITY WILL RESULT IN INCREASING CHANCES OF  
THUNDERSTORMS. MAY NEED FIRE WEATHER HIGHLIGHTS ISSUED BY MONDAY  
OR TUESDAY FOR THURSDAY AND FRIDAY. FOR NOW WILL HEADLINE THE FIRE  
WEATHER PLANNING FORECAST FOR THESE EXPECTED CHANGES COMING.  
 
THE DETERMINISTIC MODELS ARE IN GOOD AGREEMENT WITH EACH OTHER  
AND WITH THE SREF THROUGH THE SHORT TERM PERIOD. CLUSTER ANALYSIS  
FOR DAY 3 SHOWS LITTLE VARIANCE IN THE EOF1 AND EOF2 FIELDS ON DAY  
3. THE PHASE SPACE CLUSTER PLOTS SHOW THAT THE ECMWF HAS THE  
LEAST AMOUNT OF VARIANCE WITH THE DETERMINISTIC VS THE ENSEMBLE.  
THE GEFS AND CMCE HAVE GREATER VARIANCE ON THE PHASE SPACE CLUSTER  
PLOTS. REGARDLESS OF THIS, ALL MODELS ARE SHOWING AN UPPER RIDGE  
BUILDING INTO THE PACNW THROUGH MID WEEK WITH TRIPLE DIGIT  
HEAT RETURNING IN THE LOWER ELEVATIONS RETURNING BY MIDWEEK.  
 
WINDS WILL BE LIGHT FOR THE NEXT FEW DAYS AND GENERALLY TERRAIN  
DRIVEN DURING THE NIGHT AND EARLY MORNING HOURS. THEY WILL BE  
MORE DOMINATED BY THE GENERAL WINDS IN THE AFTERNOONS AND  
EVENINGS. HOWEVER, WIND SPEEDS WILL BE LIGHT DURING THE SHORT TERM  
PERIOD, EXCEPT POSSIBLY FOR LOCALLY AFTERNOON BREEZY WINDS IN THE  
EASTERN COLUMBIA GORGE AND THE KITTITAS VALLEY AS IS TYPICAL. 88  
 
LONG TERM...WEDNESDAY THROUGH SUNDAY...FOCUS IN THE LONG TERM  
CONTINUES TO BE THE HEAT POTENTIAL STARTING IN THE MIDDLE OF THE  
WORK WEEK AND POTENTIALLY LASTING THROUGH THE WEEKEND, HOWEVER  
ENSEMBLES AND GUIDANCE REMAIN OUT OF SYNC, HINDERING  
FORECAST CONFIDENCE. OVERALL MODELS ARE IN CONSENSUS ON BUILDING A  
RIDGE OF SOME KIND OVER THE PACNW DURING THE MIDDLE OF THE WORK  
WEEK, BUT DISCREPANCIES ARISE WHEN DEPICTING THE MAGNITUDE OF THE  
RIDGE, AS WELL AS POTENTIAL SURGES OF SW MOISTURE THAT WOULD NOT  
ONLY INJECT POSSIBLE CLOUD COVER OVER OUR AREA, BUT ALSO PROVIDE FOR  
SOME STORM CHANCES IN AND AROUND CENTRAL OR.  
 
LOOKING AT ENSEMBLE GUIDANCE, OVERALL VALUES ON TEMPERATURES HAVEN'T  
CHANGED MUCH FROM RUN TO RUN, WITH HIGHS AROUND 105 SUGGESTED FOR  
THE PEAK OF THE HEAT WEDNESDAY AND THURSDAY FOR THE LOWER BASIN,  
WITH AROUND 100 FOR THE FOOTHILLS OF THE BLUES, GORGE, ADJACENT  
LOWLANDS AND DOWN INTO CENTRAL OR AND 90S ELSEWHERE. BIGGEST SHIFT  
IN THE HEAT FORECAST IS TOWARD THAT OF A LONGER-DURATION EVENT, AS  
BOTH NBM AND ENSEMBLES SUGGEST TRIPLE DIGIT TEMPS COULD LAST AS LONG  
AS SUNDAY. LOOKING AT HEATRISK, SUGGESTION IS TOWARD THAT OF AN  
ADVISORY, AS THE MAGNITUDE OF THE HEAT DOESN'T STAND TO BE  
PARTICULARLY SEVERE AT THIS TIME, BUT THE DURATION OF THE HEAT WILL  
HAVE TO BE TAKEN INTO CONSIDERATION WHEN ISSUING ANY HEADLINES THIS  
WEEK.  
 
AS FAR AS MODEL DISCREPANCIES ARE CONCERNED, ENSEMBLE CLUSTERING IS  
SMOOTHING OUT A POTENTIAL CUT-OFF LOW TO OUR SOUTH DEPICTED BY  
DETERMINISTIC GUIDANCE THAT MAY PROVIDE A SURGE OF MOISTURE INTO THE  
SOUTHERN CWA. GIVEN THE LIGHT PRECIP SIGNAL ACROSS THE GFS AND  
ECMWF, AS WELL AS THE TAIL END OF THE 12Z NAM, HAVE OPTED TO LEAVE  
IN A SLIGHT CHANCE OF STORMS FOR CENTRAL OR WEDNESDAY AND THURSDAY  
EVENING, HOWEVER CONFIDENCE IS LOW AS MID-LEVEL MOISTURE LOOKS TO BE  
LACKING AND ELEVATED INSTABILITY IS NOT PARTICULARLY STRONG. REST OF  
THE FORECAST AREA LOOKS TO BE DRY THROUGH MOST OF THE PERIOD, UNTIL  
DETERMINISTIC GUIDANCE AND A FEW ENSEMBLE MEMBERS INTRODUCE AN OFF-  
SHORE LOW BY THE END OF THE WEEKEND. WILL LEAVE OUT ANY MENTION OF  
PRECIP OR STORMS THIS FAR OUT, BUT WILL KEEP AN EYE ON THIS FEATURE  
GIVEN THE CURRENT CONSENSUS ACROSS BOTH THE GFS AND ECMWF. EVANS/74  
 

 
   
AVIATION
 
VFR CONDITIONS WILL PERSIST AT ALL TAF SITES FOR THE  
NEXT 24 HOURS. SKIES ARE EXPECTED TO REMAIN MOSTLY CLEAR WITH  
WINDS GENERALLY FROM 10 TO 20 MPH DURING THE DAY. 97  
 

 
   
PRELIMINARY POINT TEMPS/POPS
 
 
PDT 56 93 58 94 / 0 0 0 0  
ALW 60 95 61 97 / 0 0 0 0  
PSC 62 96 62 98 / 0 0 0 0  
YKM 58 94 58 96 / 0 0 0 0  
HRI 59 97 61 99 / 0 0 0 0  
ELN 58 93 60 95 / 0 0 0 0  
RDM 49 92 53 94 / 0 0 0 0  
LGD 53 92 57 95 / 0 0 0 0  
GCD 54 95 56 99 / 0 0 0 0  
DLS 61 94 63 98 / 0 0 0 0  
 

 
   
PDT WATCHES/WARNINGS/ADVISORIES
 
 
OR...NONE.  
WA...NONE.  

 
 

 
 
UPDATE...99  
SHORT TERM...89  
LONG TERM....74  
AVIATION...97  
 
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