913  
FXUS66 KOTX 232346  
AFDOTX  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE SPOKANE WA  
446 PM PDT THU MAR 23 2017  
   
SYNOPSIS
 
 
MORE WET WEATHER IS ON ITS WAY. THE NEXT STORM SYSTEM WILL BRING  
WIDESPREAD RAIN AND MOUNTAIN SNOW LATE TONIGHT INTO FRIDAY,  
FOLLOWED BY SHOWERY AND BREEZY WEATHER FOR SATURDAY. SEVERAL  
INCHES OF SNOW WILL BE POSSIBLE ON SHERMAN, STEVENS, AND LOUP LOUP  
PASSES. SUNDAY LOOKS DRY. UNSETTLED WEATHER RETURNS SUNDAY NIGHT  
INTO MONDAY AND CONTINUES THROUGH NEXT WEEK, WITH SEVERAL MORE  
ROUNDS OF RAIN AND MOUNTAIN SNOW.  
 

 
   
DISCUSSION
 
 
TONIGHT INTO FRIDAY: A MOIST WEATHER SYSTEM WILL MOVE ACROSS THE  
CASCADES TONIGHT, WITH A WARM FRONT LIFTING ACROSS NORTH CENTRAL  
WASHINGTON INTO NORTHEAST WASHINGTON. FOLLOWING CLOSE BEHIND, AN  
OCCLUDED FRONT WILL SLOWLY MOVE ACROSS THE REGION ON FRIDAY. A  
SOUTHWEST ORIENTATED JET STREAK ALOFT WILL BE OVER THE REGION.  
THEN A PWAT PLUME OF 0.5" TO 0.75" WILL BE ALIGNED WITH THE  
BOUNDARIES THROUGH MIDDAY FRIDAY BEFORE THE PLUME SAGS SOUTH AND  
EXITS THE REGION. LOW LEVEL EASTERLY FLOW AND GOOD ISENTROPIC LIFT  
OVERNIGHT WILL BRING LIGHT TO MODERATE PRECIPITATION ACROSS NORTH  
CENTRAL WASHINGTON AND MOST OF THE CASCADES. SNOW LEVELS SHOULD  
BE NEAR 3KFT, ALTHOUGH AREAS FROM THE METHOW VALLEY TO REPUBLIC  
STAND TO SEE A LITTLE SNOW ACCUMULATIONS LESS THAN 2 INCHES  
OVERNIGHT INTO FRIDAY MORNING, ESPECIALLY ALONG THE HIGHWAY 20  
CORRIDOR. THE HIGHER MOUNTAINS COULD SEE 2 TO 5 INCHES BY FRIDAY  
AFTERNOON.  
 
BEHIND THE FRONT FRIDAY AFTERNOON AND EVENING, INSTABILITY WILL  
INCREASE AND WE COULD SEE SHOWERS DEVELOPING OVER THE CASCADES.  
TEMPERATURES WILL COOL FRIDAY NIGHT WITH SNOW LEVELS TUMBLING INTO  
THE NORTHERN VALLEYS AS THE SHOWERS DECREASE. BY SATURDAY AND  
SATURDAY NIGHT, AN UPPER LEVEL TROUGH WILL BE OVER THE REGION.  
SOUTHWEST LOW LEVEL FLOW WILL ENHANCE OROGRAPHIC SHOWERS OVER THE  
MOUNTAINS OF NORTHEAST WASHINGTON AND THE IDAHO PANHANDLE  
ESPECIALLY SATURDAY AFTERNOON. THE SHOWERS ARE FORECAST TO FINALLY  
DECREASE SATURDAY NIGHT, FOLLOWED BY COOLER OVERNIGHT  
TEMPERATURES WITH SUB FREEZING TEMPERATURES POSSIBLE IN THE  
NORTHERN VALLEYS. /RFOX  
 
HYDROLOGY: OVERALL, QPF AMOUNTS HAVE NOT WAVERED TOO MUCH FOR THE  
REGION. ANTICIPATE 24 HOUR RAINFALL AMOUNTS OF UP TO A QUARTER OF  
A INCH IN THE LEE SIDE CASCADE VALLEYS AND WESTERN COLUMBIA  
BASIN, WHILE UP TO A HALF AN INCH OF PRECIPITATION IS EXPECTED  
FROM EXTREME EASTERN WASHINGTON INTO NORTH IDAHO. THIS MAY EFFECT  
THE CURRENT FLOODING AND COULD CAUSE SECONDARY RISES ON AREA  
RIVERS AND STREAMS. THIS WEATHER SYSTEM MAY BE WET, YET IT LACKS  
THE LONG DURATION, THE WARMER TEMPERATURES, AND SIGNIFICANT SNOW  
MELT ACCOMPANIED WITH PREVIOUS WEATHER SYSTEMS. THE IMPACTS FROM  
THIS MOIST SYSTEM ARE NOT EXPECTED TO BE AS SUBSTANTIAL AND MAY  
JUST PROLONG THE CURRENT FLOOD SITUATION. THE CURRENT AREAL FLOOD  
WARNING WILL CONTINUE THROUGH MIDDAY SATURDAY FOR THE OKANOGAN  
HIGHLANDS, NORTHEAST WASHINGTON AND PARTS OF NORTH IDAHO. MAINSTEM  
RIVERS WILL SEE A DOWNWARD TREND INTO THE WEEKEND. /RFOX  
 
SUNDAY TO THURSDAY: THE INLAND NW REMAINS IN AN ACTIVE  
PATTERN, WITH SEVERAL OPPORTUNITIES FOR PRECIPITATION. THE  
BROADEST CHANCES WILL BE BETWEEN LATE SUNDAY AND MONDAY AND AGAIN  
TOWARD WEDNESDAY. SNOW LEVELS WILL AVERAGE BETWEEN 3-5KFT, MEANING  
THE PRECIPITATION THAT FALLS SHOULD BE MAINLY VALLEY RAIN AND  
MOUNTAIN SNOW. HOWEVER SOME SNOW COULD MIX DOWN TO SOME VALLEY  
FLOORS AT NIGHT, PARTICULARLY CLOSER TO THE CASCADES AND CANADIAN  
BORDER.  
 
SUNDAY HIGH PRESSURE WILL BE EDGING EAST WHILE THE NEXT  
SYSTEM STARTS TO APPROACH IN THE AFTERNOON. IN THE MORNING THERE  
WILL THE POTENTIAL FOR SOME PATCHY FOG IN THE SHELTERED EASTERN  
VALLEYS. IN THE AFTERNOON PRECIPITATION CHANCE START TO INCREASE.  
THERE ARE DIFFERENCES AS TO HOW QUICK THAT PRECIPITATION MOVES IN,  
BUT THE BEST CHANCES WILL BE OVER THE CASCADES. I ADDED SLIGHT  
CHANCES JUST EAST OF THE CASCADES, WHILE THE FORECAST FOR THE  
EASTERN THIRD OF WA AND THE ID PANHANDLE STAYS DRY. SUNDAY NIGHT  
THE WARM FRONT AND ASSOCIATED PRECIPITATION LIFTS IN AND THE  
THREAT REMAINS HIGH INTO MONDAY AS THE COLD FRONT/SUPPORTING UPPER  
TROUGH MOVES IN, BEFORE THE PRECIPITATION THREAT STARTS TO WANE  
BEHIND IT. THERE ARE DIFFERENCES AS TO HOW QUICK THAT COLD  
FRONT/UPPER TROUGH SLIDE IN SO DIFFERENCES AS TO WHEN THE THREAT  
STARTS TO WANE.  
 
MONDAY NIGHT THROUGH TUESDAY NIGHT THE MODEL DIFFERENCES  
CONTINUE, WITH SOME SOLUTIONS QUICKLY BRINGING IN ANOTHER  
SHORTWAVE TROUGH WITH MORE SHOWERS AND OTHERS DRYING OUT THE  
REGION WITH A SHORTWAVE RIDGE. WITH THOSE DIFFERENCES THE FORECAST  
TRENDS TOWARD CLIMATOLOGY.  
 
BETWEEN TUESDAY NIGHT AND THURSDAY THE NEXT FRONTAL WAVE MAKES  
ITS WAY INLAND. THE LEADING WARM FRONT STARTS IN TUESDAY NIGHT  
INTO WEDNESDAY BEFORE COLD FRONT PASSES WEDNESDAY NIGHT INTO  
THURSDAY. THE SYSTEM TAPS A MODEST MOISTURE TAP, WITH PWATS RISING  
TO BETWEEN 0.50 TO 0.75 INCHES. SO THIS SYSTEM IS A BIT WETTER.  
THE STEADIER PRECIPITATION THREAT DEVELOPS TUESDAY NIGHT INTO  
WEDNESDAY MORNING AND COULD BE LOCALLY MODERATE THROUGH WEDNESDAY  
EVENING. THE THREAT CONTINUES INTO THURSDAY WITH THE UPPER TROUGH  
COMING IN BUT PRECIPITATION LOOKS MORE SHOWERY. /J. COTE'  
 

 
   
AVIATION
 
 
00Z TAFS: AN OCCLUDED FRONT WILL MOVE INTO THE REGION TONIGHT.  
EXPECT CLOUDS TO THICKEN FROM THE TOP DOWN THROUGH THIS EVENING  
WITH RAIN MOVING INTO KEAT AFTER 06Z AND INTO THE PANHANDLE AFTER  
12Z. RAINFALL WILL BE LIGHT BUT STEADY FOR A 12 HOUR PERIOD OVER  
MUCH OF THE REGION. CIGS/VIS ARE EXPECTED TO LOWER INTO MVFR  
CATEGORY THROUGH THE MORNING ON FRIDAY WITH LITTLE IMPROVEMENT AT  
KGEG, KSFF, KCOE AND KPUW FOR THE AFTERNOON. THE FRONT WILL CLEAR  
THE WESTERN PORTION OF THE BASIN BY MID AFTERNOON WITH CONVECTIVE  
SHOWERS FORMING BEHIND THE FRONT BY LATE AFTERNOON FRIDAY. /SVH  
 

 
   
PRELIMINARY POINT TEMPS/POPS
 
 
SPOKANE 35 44 35 49 32 51 / 20 100 60 50 10 10  
COEUR D'ALENE 33 43 35 47 32 49 / 10 100 80 70 10 10  
PULLMAN 37 46 36 49 33 52 / 20 100 70 60 10 10  
LEWISTON 39 52 38 53 35 57 / 10 90 70 60 10 10  
COLVILLE 34 45 34 50 29 49 / 20 90 70 60 10 10  
SANDPOINT 30 41 33 44 29 46 / 10 90 80 60 20 10  
KELLOGG 32 42 33 43 31 47 / 10 90 90 70 30 10  
MOSES LAKE 40 52 36 58 31 55 / 50 80 20 10 0 10  
WENATCHEE 36 49 34 52 31 48 / 80 60 20 10 0 20  
OMAK 35 46 33 51 30 49 / 70 90 30 20 10 20  
 

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

 
 

 
 
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