036  
FXUS66 KOTX 151138  
AFDOTX  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE SPOKANE WA  
438 AM PDT WED AUG 15 2018  
   
SYNOPSIS
 
 
GENERALLY DRY CONDITIONS WILL CONTINUE THROUGH THIS WEEK. HAZE AND  
SMOKE WILL CONTINUE OVER MOST OF THE AREA FROM TIME TO TIME.  
TEMPERATURES WILL WARM BACK ABOVE AVERAGE THROUGH THE WEEK, BUT  
NOT AS HOT AS LAST WEEK. THURSDAY AND FRIDAY, A SMALL CHANCE OF  
THUNDERSTORMS WILL DEVELOP OVER SOUTHEAST WASHINGTON AND THE IDAHO  
PANHANDLE.  
 

 
   
DISCUSSION
 
 
TODAY: A RIDGE OF HIGH PRESSURE WILL BUILD NORTHWARD OVER THE AREA  
TODAY. INCREASING SUBSIDENCE ALOFT WILL YIELD ANOTHER 1-3C OF  
WARMING AT 850MB PUSHING AFTERNOON HIGHS INTO THE 90S OR ROUGHLY  
2-4 DEGREES WARMER THAN TUESDAY. WEAK PRESSURE GRADIENTS WILL ONCE  
AGAIN DELIVER ANOTHER AFTERNOON OF LIGHT TERRAIN DRIVEN WINDS  
HAVING LITTLE TO NO IMPACT ON THE CURRENT SMOKE ENVELOPING THE  
REGION. CURRENT AIR QUALITY INDICES AROUND THE REGION CONTINUE TO  
SHOW UNHEALTHY TO VERY UNHEALTHY AIR AND I SEE LITTLE EVIDENCE  
THAT THIS WILL IMPROVE IN THE NEXT 24 HOURS.  
 
THURSDAY: THE UPPER-LEVEL RIDGE AXIS WILL SHIFT TO THE EAST SLIGHTLY  
AS A WEAK TROUGH MOVES INTO WESTERN WA. THE AIR MASS WILL  
CONTINUE TO WARM UNDER INCREASING SOUTH/SOUTHWESTERLY FLOW  
YIELDING AN ADDITIONAL 1-2 DEGREES OF WARMING IN AFTERNOON HIGHS.  
WE WILL BE TRACKING THE FIRST INSURGENCE OF MONSOONAL MOISTURE  
COMING OUT OF OREGON AS EARLY AS WEDNESDAY NIGHT AND INTO  
THURSDAY. THIS IS WELL AGREED UPON BY THE MODELS BUT CONFIDENCE IS  
LOW FOR ACTUAL THUNDERSTORMS GIVEN THE LACK OF MIDLEVEL FORCING.  
SREF PROBABILITIES FOR THUNDER CONTINUE TO KEEP THE BEST CHANCES  
AROUND THE BLUE MOUNTAINS AND INTO THE HIGHER TERRAIN OF THE LOWER  
IDAHO PANHANDLE THURSDAY AFTERNOON. WE HAVE ALSO MAINTAINED A  
SMALL THREAT ALONG THE HIGHEST PEAKS OF THE NORTH PANHANDLE AND  
NE WA GIVEN BORDERLINE CIN AND POTENTIAL FOR AN ISOLATED CELL IN  
THE LATE AFTERNOON. WINDS WILL START OFF LIGHT AND TERRAIN DRIVEN  
THEN SHOULD BEGIN TO INCREASE FROM THE WEST/NORTHWEST ACROSS THE  
EAST SLOPES OF THE CASCADES AS A SHALLOW MARINE LAYER SURGES INTO  
WESTERN WA AND CROSS-CASCADE PRESSURE GRADIENTS INCREASE NEAR 4-6  
MB. THIS WOULD BE LATE IN THE DAY AFTER 5PM.  
 
THURSDAY NIGHT AND FRIDAY. THE UPPER-LEVEL TROF WILL BECOME BETTER  
ORGANIZED AND TRACK INLAND BRINGING THE GREATEST RISK FOR SHOWERS  
AND THUNDERSTORMS. THE FOCUS WILL REMAIN ACROSS SOUTHEASTERN WA  
AND LOWER IDAHO PANHANDLE UNDER AN AREA OF DIFFLUENT FLOW ALOFT. A  
SLIGHT SHIFT IN THE TROF MAY ALLOW A FEW CELLS TO SNEAK INTO NE  
WA AND N ID BUT THIS CARRIES LOWER CONFIDENCE. THE CASCADES  
CONTINUE TO CARRY THE LOWEST RISK FOR ANY THUNDER ACTIVITY. MOST  
UNSTABLE CAPE THURSDAY NIGHT INTO FRIDAY MORNING IS BETWEEN  
700-300MB IS ON THE ORDER OF 200-600 J/KG VIA THE NAM WHICH IS  
SUFFICIENT FOR NOCTURNAL, HIGH BASED STORMS. THIS IS VERY  
CONCERNING FOR ADDITIONAL FIRE STARTS GIVEN THE CURRENT DRYNESS  
LEVELS ACROSS THE REGION AND WILL NEED TO MONITORED CLOSELY FOR  
POTENTIAL FIRE WEATHER HIGHLIGHTS. THE MARINE LAYER WEST OF THE  
CASCADE CREST WILL CONTINUE TO DEEPEN BRINGING A STRONGER PUSH OF  
WEST TO NORTHWEST WINDS THROUGH THE CASCADE GAPS AND EAST SLOPES  
THURSDAY EVENING AND NIGHT. WINDS OF 10-20 MPH WILL BE POSSIBLE AS  
PRESSURE GRADIENTS INCREASE NEAR 8MB. A LIGHT PUSH OF SOUTHWEST  
WINDS WILL ALSO SPREAD TOWARD THE PALOUSE AND SOUTHWESTERN BASIN  
AS COOLER MARINE AIR SPILLS INLAND THROUGH THE COLUMBIA GORGE.  
SMOKE WILL REMAIN AN ISSUE FOR MANY AREAS OF THE INLAND NW BUT  
SOME RELIEF IS POSSIBLE AROUND THE CASCADES AND WESTERN BASIN WITH  
THIS SHORT-LIVED PUSH OF WESTERLY WINDS. /SB  
 
FRIDAY NIGHT THROUGH TUESDAY: THE SHORT WAVE TROUGH TRACKS EAST  
OF THE REGION INTO MONTANA FRIDAY NIGHT WITH WEAK HIGH PRESSURE  
BUILDING IN FOR SATURDAY. THE RIDGE AMPLIFIES OFF THE COAST SUNDAY  
INTO MONDAY TURNING THE FLOW NORTHERLY. A MID LEVEL WAVE DROPS  
DOWN HEADING MAINLY INTO MONTANA ALTHOUGH CAN NOT COMPLETELY RULE  
OUT CONVECTION OVER THE MOUNTAINS OF NE WASHINGTON AND NORTH IDAHO  
SUNDAY AFTERNOON/EVENING. HIGH PRESSURE IS THEN PROGGED BY THE  
GEFS AND ECMWF TO MOVE OVER THE REGION TUESDAY.  
 
SMOKE AND HAZE IS EXPECTED TO CONTINUE INTO THE WEEKEND AS  
REGIONAL WILDFIRES CONTINUE FROM BRITISH COLUMBIA DOWN THROUGH  
WASHINGTON, OREGON, IDAHO, MONTANA, AND CALIFORNIA. THERE ARE NO  
STRONG WINDS FORECAST TO TAKE THE SMOKE OUT OF THE AREA. AS THE  
RIDGE AMPLIFIES OFF THE COAST EARLY NEXT WEEK COULD SEE ADDITIONAL  
SMOKE MOVE INTO THE REGION FROM CANADA AS NORTHERLY FLOW  
DEVELOPS. 850MB TEMPERATURES REMAIN WARM THROUGH THE  
PERIOD...BETWEEN 21-25C. THIS SUPPORTS ABOVE NORMAL TEMPERATURES  
ALTHOUGH SMOKE WILL PROBABLY KNOCK OFF AT LEAST 2-3 DEGREES OFF  
THE HIGH TEMPERATURES COMPARED TO WHAT WE WOULD SEE WITHOUT SMOKE  
AND THIS WAS FACTORED INTO THE HIGH TEMPERATURE FORECAST. JW  
 

 
   
AVIATION
 
 
12Z TAFS: EXPECT CONTINUED SMOKE AND HAZE TO KEEP PRODUCING VIS  
ISSUES FOR ALL TAF SITES. WENT CLOSE TO PERSISTENCE FOR THE NEXT  
24 HOURS BUT THIS CARRIES MODERATE UNCERTAINTY GIVEN VARIATION IN  
SMOKE OUTPUT FROM FIRES AND SLIGHT WIND SHIFTS. SOME MIDLEVEL  
MOISTURE WILL COME INTO KLWS/KPUW OVERNIGHT WITH CIGS AT OR ABOVE  
15K FT AGL. /SB  
 

 
   
PRELIMINARY POINT TEMPS/POPS
 
 
SPOKANE 93 67 95 66 90 62 / 0 0 0 10 20 10  
COEUR D'ALENE 92 63 93 62 89 58 / 0 0 0 10 20 10  
PULLMAN 93 60 94 63 87 56 / 0 0 0 20 30 10  
LEWISTON 99 69 100 68 93 64 / 0 0 10 20 30 10  
COLVILLE 94 56 96 57 94 54 / 0 0 0 10 10 10  
SANDPOINT 88 54 91 54 88 51 / 0 0 0 10 20 10  
KELLOGG 89 59 91 58 87 56 / 0 0 10 20 20 10  
MOSES LAKE 96 63 98 61 93 58 / 0 0 0 10 10 0  
WENATCHEE 95 67 95 66 92 64 / 0 0 0 10 0 0  
OMAK 96 62 98 63 94 62 / 0 0 0 0 0 0  
 

 
   
OTX WATCHES/WARNINGS/ADVISORIES
 
 
ID...NONE.  
WA...NONE.  
 

 
 

 
 
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