111  
FXUS66 KOTX 291123  
AFDOTX  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE SPOKANE WA  
423 AM PDT MON MAY 29 2017  
   
SYNOPSIS
 
 
HIGH PRESSURE CONTINUES OVER THE INLAND NORTHWEST THROUGH TUESDAY  
WITH UNSEASONABLY WARM TEMPERATURES. THERE IS A SMALL CHANCE OF  
THUNDERSTORMS IN THE HIGHER ELEVATIONS, OTHERWISE EXPECT DRY  
WEATHER. THIS WARM SPELL WILL CONTRIBUTE TO RISES ON RIVERS FROM  
THE CASCADES INTO NORTH IDAHO. A COLD FRONT ARRIVES TUESDAY NIGHT  
WITH A BETTER CHANCE OF SHOWERS AND THUNDERSTORMS. THIS WILL BE  
FOLLOWED BY COOLER AND UNSETTLED WEATHER FOR WEDNESDAY INTO THE  
REST OF THE WEEK.  
 

 
   
DISCUSSION
 
 
TODAY THROUGH TUESDAY: WARM WEATHER CONTINUES, WITH LIMITED SHOWER  
AND THUNDERSTORM CHANCES. A RIDGE OF HIGH PRESSURE CENTERED OVER  
THE INLAND NW THIS MORNING WILL START TO EDGE EAST. MOISTURE  
LINGERING AROUND THE NORTH TO EASTERN CWA AND INCREASING TOWARD  
THE CASCADES WITH BE ACCOMPANIED BY THE REEMERGENCE OF AFTERNOON  
INSTABILITY. SUBTLE VORTICITY LOBES IN THE WESTERLY FLOW AND  
OROGRAPHIC ASCENT WILL LEAD TO AN INCREASE IN CUMULUS ABOUT THE  
MOUNTAIN ZONES THIS AFTERNOON. THIS WILL BE ACCOMPANIED BY A  
SLIGHT RISK FOR SHOWERS AND THUNDERSTORMS IN THE CASCADES, THE  
NORTHERN WA AND ID PANHANDLE MOUNTAINS, AS WELL AS THE BLUES.  
TONIGHT THE RISK WILL WANE FOR MOST LOCATIONS WITH THE LOSS OF  
DAYTIME HEATING, THOUGH SOME THREAT MAY LINGER NEAR THE CASCADE  
CREST WITH THE ONSHORE FLOW. TUESDAY THE RIDGE AXIS SHIFTS INTO  
THE NORTHERN ROCKIES AND THE SOUTHWEST FLOW INCREASES. MOISTURE  
FURTHER DEEPENS AROUND THE CASCADES AHEAD OF THE APPROACHING  
SYSTEM. A LIMITED SHOWER AND THUNDERSTORM THREAT WILL BE FOUND  
NEAR THE BLUES AND FAR NORTHEASTERN MOUNTAINS WITH THE AFTERNOON  
HEATING AND INSTABILITY. A BETTER THREAT OF SHOWERS AND  
THUNDERSTORMS WILL BE DEVELOPING WITHIN THE CASCADES, ESPECIALLY  
LATE. MIDDLE TO HIGH CLOUDS WILL GRADUALLY INCREASE FROM THE WEST  
ELSEWHERE. EASTERLY WINDS WILL INCREASE. TEMPERATURES WILL REMAIN  
ABOVE NORMAL BY ABOUT 10-15 DEGREES, WITH AFTERNOON HIGHS IN THE  
80S TO LOWER 90S. TUESDAY WILL BE THE WARMEST DAY FOR MOST SPOTS.  
THE MAIN EXCEPTION WILL BE TOWARD THE CASCADES WHERE THE INCREASED  
ONSHORE FLOW AND INCREASED CLOUD COVER AND SHOWER CHANCES MAY  
HOLD TEMPERATURES DOWN COMPARED TO TODAY. /J. COTE'  
 
TUESDAY NIGHT AND WEDNESDAY: MODELS ARE IN GOOD AGREEMENT IN  
BREAKING DOWN THE WARM UPPER RIDGE WITH AN INITIAL SHORT WAVE  
PASSAGE AND SURFACE COLD FRONT TUESDAY NIGHT AND INTO WEDNESDAY  
MORNING. THE MAIN FRONTAL TRANSIT WILL OCCUR OVERNIGHT TUESDAY AND  
INTO WEDNESDAY MORNING...NOT THE MOST FAVORABLE TIME FOR SERIOUS  
THUNDERSTORM ACTIVITY...HOWEVER ENOUGH MID LEVEL INSTABILITY AND  
PLENTY OF MOISTURE WILL BE ABLE TO BE EXPLOITED BY THE SHORT WAVE  
DYNAMICS TO PRODUCE A FEW THUNDERSTORMS MOVING OFF THE CASCADES IN  
THE EVENING AND NOCTURNALLY TRANSITING THE BASIN AND NORTHERN  
MOUNTAINS OVERNIGHT...AND REDEVELOPING WITH A SURFACE BASED  
INSTABILITY COMPONENT DURING THE DAY WEDNESDAY CONCENTRATED OVER  
THE IDAHO PANHANDLE. OTHERWISE...BREEZY CONDITIONS WILL DEVELOP  
OVER THE BASIN AS COOLER AIR BEHIND THE FRONT INVADES THROUGH THE  
CASCADE GAPS. A GENERAL THREAT OF SHOWERS WITH A FEW THUNDERSTORMS  
LOOKS PLAUSIBLE DURING THIS EVOLUTION.  
 
WEDNESDAY NIGHT THROUGH SUNDAY: ALTHOUGH TIMING DIFFERENCES  
DEVELOP BETWEEN MODELS THROUGH THIS PERIOD...ALL OF THEM DEPICT A  
SERIES OF SHORT WAVE DISTURBANCES TRANSITING THE FORECAST AREA IN  
A MORE PROGRESSIVE PATTERN FOR THE REMAINDER OF THE WEEK AND INTO  
NEXT WEEKEND. NONE OF THESE WAVES LOOK PARTICULARLY STRONG...BUT  
EACH WILL BE CAPABLE OF TRIGGERING SOME SHOWERS OR A FEW  
THUNDERSTORMS MAINLY OVER THE MOUNTAINS NORTH AND EAST OF THE  
BASIN...WITH OCCASIONALLY BREEZY CONDITIONS IN THE BASIN ITSELF.  
TEMPERATURES WILL COOL BACK INTO THE NORMAL RANGE DURING THIS  
PATTERN...WITH MAINLY 70S READINGS IN THE POPULATED AREAS DURING  
THE DAY AND 40S TO LOWER 50S AT NIGHT. /FUGAZZI  
 

 
   
AVIATION
 
 
12Z TAFS: DOMINATING RIDGE WILL LEAD TO VFR CONDITIONS AT ALL TAF  
SITES. ISOLATED THUNDERSTORMS POSSIBLE NEAR THE CASCADE CREST AND  
OVER THE HIGHER TERRAIN OF NORTHEAST WA AND THE NORTHERN ID  
PANHANDLE THIS AFTERNOON, AWAY FROM THE TAFS. /J. COTE'  
 

 
   
PRELIMINARY POINT TEMPS/POPS
 
 
SPOKANE 86 60 87 58 75 53 / 10 0 0 40 20 10  
COEUR D'ALENE 84 56 86 55 74 51 / 10 0 0 30 20 20  
PULLMAN 83 55 85 55 73 52 / 10 0 0 20 20 30  
LEWISTON 90 59 91 61 80 56 / 10 0 0 20 20 30  
COLVILLE 87 56 87 58 76 52 / 10 0 0 40 40 20  
SANDPOINT 83 53 84 54 75 49 / 10 10 10 10 40 40  
KELLOGG 84 53 84 53 76 47 / 10 10 0 10 30 50  
MOSES LAKE 92 58 94 60 83 55 / 10 0 0 40 10 10  
WENATCHEE 90 64 89 58 80 58 / 10 10 10 30 10 10  
OMAK 89 58 90 60 81 53 / 10 10 10 50 40 10  
 

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

 
 

 
 
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