849  
FXUS66 KOTX 271122  
AFDOTX  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE SPOKANE WA  
422 AM PDT SAT MAY 27 2017  
   
SYNOPSIS
 
 
HIGH PRESSURE BUILDS OVER THE REGION THIS WEEKEND. LIMITED  
THUNDERSTORM CHANCES DEVELOP AROUND THE CASCADES, AND PERHAPS THE  
CANADIAN BORDER, IN THE AFTERNOON BETWEEN SUNDAY AND TUESDAY.  
OTHERWISE EXPECT DRY, WARM WEATHER INTO EARLY NEXT WEEK, WITH  
AFTERNOON HIGHS IN THE 80S. THIS MILD WEATHER WILL CONTRIBUTE TO  
RISES ON RIVERS IN CENTRAL AND NORTH CENTRAL WASHINGTON. A THREAT  
OF UNSETTLED WEATHER RETURNS AROUND MIDDLE TO LATE NEXT WEEK, WITH  
SLIGHTLY COOLER TEMPERATURES.  
 

 
   
DISCUSSION
 
 
TODAY THROUGH SUNDAY: THE INLAND NW WILL BE DOMINATED BY A  
RIDGE OF HIGH PRESSURE WITH LARGELY DRY AND WARM CONDITIONS. THIS  
MORNING WV IMAGERY SHOWS THE RIDGE AXIS NEAR THE PACIFIC COASTLINE  
AND IT WILL SLOWLY EDGE TOWARD THE CASCADES LATE TODAY INTO  
TONIGHT. A FEW HIGH CLOUDS WILL SPILL OVER ITS TOP AND INTO  
EASTERN WA/NORTH ID. AFTERNOON HEATING SHOULD LEAD TO SOME CUMULUS  
BUILD-UPS AROUND THE MOUNTAINS. THERE WILL ALSO BE A SLIM THREAT  
OF A SHOWER OR TWO AROUND THE MOUNTAINS NEAR THE CANADIAN BORDER.  
OTHERWISE FAIR CONDITIONS ARE EXPECTED, WITH TEMPERATURES PUSHING  
ABOVE NORMAL BY ABOUT 10 DEGREES UNDER THE BUILDING RIDGE. SUNDAY  
THE RIDGE AXIS EDGES INTO EASTERN WA. THE SOUTHWEST FLOW THAT  
DEVELOPS ON ITS BACKSIDE WILL CARRY A WEAKENING DISTURBANCE UP AND  
AROUND THE CASCADES. WITH INCREASING INSTABILITY IN THE HEATING  
OF THE DAY THIS WILL ALLOWING FOR A LIMITED THREAT OF SHOWERS AND  
THUNDERSTORM AROUND THE CASCADES AND NORTHERN MOUNTAINS BY  
AFTERNOON. OTHERWISE DRY CONDITIONS ARE EXPECTED WITH THIN HIGH  
CLOUDS AND FEW CUMULUS BUILD-UPS AROUND THE MOUNTAINS AGAIN.  
AFTERNOON HIGH TEMPERATURES ARE EXPECTED TO BE 10-15 DEGREES ABOVE  
NORMAL. /J. COTE'  
 
MONDAY AND TUESDAY: WARM AND DRY CONDITIONS WITH TEMPERATURES  
RUNNING 10 TO 15 DEGREES ABOVE NORMAL WILL PERSIST THROUGH TUESDAY  
OVER THE REGION. THERE WILL BE A SMALL CHANCE OF AFTERNOON AND  
EVENING THUNDERSTORMS MAINLY OVER THE CASCADES BOTH AFTERNOONS AND  
EARLY EVENINGS. ANY STORMS WILL BE BRIEF BUT COULD REMAIN NEARLY  
STATIONARY OVER THEIR MOUNTAIN NURSERIES LONG ENOUGH TO PRODUCE A  
FEW TENTHS OF AN INCH OF RAIN AT ANY PARTICULAR LOCATION.  
 
BEYOND TUESDAY MODELS ARE SIMILAR IN INITIATING A BREAK DOWN  
PHASE...BUT THERE ARE DIFFERENCES IN THE CHARACTER AND DETAILS  
LEADING TO HIGH CONFIDENCE OF AN INCREASED CHANCE OF SHOWERS AND  
THUNDERSTORMS BROADENING OUT OVER THE ENTIRE FORECAST AREA ON  
WEDNESDAY AND THURSDAY AND A COOL DOWN TO NEAR NORMAL HIGHS AND  
LOWS. THE GFS HAS FLIP-FLOPPED OVER THE LAST COUPLE RUNS TO NOW  
BEING MORE DELAYED AND LESS AGGRESSIVE THAN THE ECMWF MODEL...THE  
GFS DEPICTS THURSDAY AS THE HIGHEST THREAT FOR SIGNIFICANT WEATHER  
WHILE THE EC MODELS SUGGESTS WEDNESDAY WILL BE THE DAY OF A  
POTENTIALLY THUNDERY COLD FRONT PASSAGE. THE CANADIAN SUPPORTS THE  
ECMWF SOLUTION AND THESE MODELS HAVE BEEN MORE STABLE AND  
CONSISTENT OVER THE LAST FEW RUNS THAN THE GFS. THUS...THE  
FORECAST WILL REFLECT A DETERIORATION STARTING ON  
WEDNESDAY...WITH THE UNSETTLED SHOWERY COOL DOWN CONTINUING  
THURSDAY AND POSSIBLY INTO FRIDAY...BUT WEDNESDAY AND THURSDAY  
LOOK LIKE THE BEST BET FOR ANY PRECIPITATION OVER THE REGION  
IN GENERAL. /FUGAZZI  
 

 
   
AVIATION
 
 
12Z TAFS: FLAT CUMULUS EXPECTED MAINLY OVER THE HIGHER TERRAIN  
SATURDAY AFTERNOON; OTHERWISE, VFR CONDITIONS AND WEAK WINDS WILL  
CONTINUE ACROSS THE REGION THROUGH 12Z SUNDAY. /J. COTE'  
 

 
   
PRELIMINARY POINT TEMPS/POPS
 
 
SPOKANE 79 54 82 56 85 57 / 0 0 0 0 0 0  
COEUR D'ALENE 78 49 82 51 84 53 / 0 0 10 0 0 0  
PULLMAN 76 48 81 50 82 52 / 0 0 0 0 0 0  
LEWISTON 83 53 88 57 89 58 / 0 0 0 0 0 0  
COLVILLE 81 52 84 52 87 53 / 0 0 10 0 0 0  
SANDPOINT 76 47 79 48 81 49 / 10 0 10 10 10 10  
KELLOGG 76 47 82 48 81 49 / 0 10 10 10 10 0  
MOSES LAKE 85 52 88 55 91 58 / 0 0 0 0 0 0  
WENATCHEE 85 57 87 59 89 60 / 0 0 0 0 0 10  
OMAK 85 53 87 54 87 56 / 0 0 10 0 0 10  
 

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

 
 

 
 
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