256  
FXUS66 KOTX 260919  
AFDOTX  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE SPOKANE WA  
219 AM PDT THU APR 26 2018  
   
SYNOPSIS
 
 
WARM AND DRY WEATHER PERSISTS UNTIL FRIDAY WITH MANY LOWLAND  
SPOTS REACHING 80. EXPECT AN ABRUPT PATTERN CHANGE WITH BREEZY,  
COOLER AND SHOWERY WEATHER FOR THE WEEKEND. DRIER AND WARMER  
WEATHER ARRIVES BY THE MIDDLE OF NEXT WEEK.  
 

 
   
DISCUSSION
 
 
TODAY THROUGH SATURDAY: BIG CHANGES HAPPENING IN THE NEXT FEW  
DAYS. THE RIDGE OF HIGH PRESSURE WILL PERSIST OVER THE INLAND  
NW TODAY AND FRIDAY, BRINGING UNSEASONABLE WARMTH AND DRY WEATHER.  
WINDS SHOULD BE LIGHT AND PRIMARILY EASTERLY WITH A SURFACE HIGH  
OVER THE ROCKIES AND A THERMALLY INDUCED PRESSURE TROUGH OVER  
WESTERN OREGON. THIS TROUGH WILL SLOWLY PUSH NORTH AND EAST BY  
FRIDAY, MAKING ITS WAY ACROSS THE CASCADES INTO THE COLUMBIA  
BASIN. WARM AIR ADVECTION CONTINUES AND SHOULD SEE A FEW DEGREES  
OF WARMING OVER THE NEXT COUPLE OF DAYS, PEAKING FRIDAY WITH THE  
LOW LEVEL THERMAL RIDGE SPANNING FROM NORTH IDAHO INTO NORTHEAST  
WASHINGTON. LOW LAND TEMPERATURES REACHING 80 ARE POSSIBLE IN  
SEVERAL LOCATIONS.  
 
LOW PRESSURE SPINNING IN THE PACIFIC WILL MOVE INLAND FRIDAY AND  
PRESS TOWARD THE REGION FRIDAY NIGHT WITH A COLD FRONT MOVING UP  
FROM THE SOUTH. WINDS VEER TO THE SOUTHWEST TO WEST, BECOMING  
GUSTY FRIDAY NIGHT ACROSS THE COLUMBIA BASIN AND CENTRAL CASCADES.  
SHOWERS ADVANCE NORTHWARD WITH THE FRONT FRIDAY NIGHT. INSTABILITY  
INCREASES ACROSS THE BLUE MOUNTAINS AND CAMAS PRAIRIE FRIDAY  
EVENING AHEAD OF THE FRONT AND COULD SEE A SMALL CHANCE OF  
THUNDERSTORM, ALTHOUGH THIS AREA WILL BE CAPPED AND NEEDS THE LIFT  
FROM THE FRONT OR CONVECTION DOWNSTREAM IN OR TRACKING INTO THE  
REGION FOR ACTIVITY TO START. THE BEST MID LEVEL INSTABILITY AND  
LIFT SPANS ACROSS NORTHEAST OREGON INTO NORTH CENTRAL IDAHO. THE  
MORE NOTEWORTHY CHANGE WILL BE THE INCREASE OF SHOWERS FRIDAY  
NIGHT AND EXPANDING ON SATURDAY AS A WELL DEFINED DEFORMATION BAND  
ROTATES FROM SOUTHEAST TO NORTHWEST ACROSS EASTERN WASHINGTON. A  
SWATH OF HALF OF INCH OR MORE OF PRECIPITATION IS POSSIBLE ACROSS  
CENTRAL INTO EASTERN WASHINGTON, WHILE LIGHTER SHOWERS WILL BE  
FOUND ACROSS NORTH IDAHO. TEMPERATURES WILL STRUGGLE TO RISE  
SATURDAY UNDER THE CLOUD COVER AND SHOWERS, WITH DAYTIME HIGHS  
ONLY REACHING THE MID 50S TO MID 60S, SOME 20 DEGREES COOLER THAN  
FRIDAY. THE WARM WEATHER FOLLOWED BY THE PRECIPITATION WILL  
CONTINUE THE MOUNTAIN SNOW MELT AND INCREASED RUNOFF WITH RISES IN  
AREAS RIVERS TAKING NOTICE THIS WEEKEND. /RFOX.  
 
SUNDAY AND MONDAY: THE LOW WILL CONTINUE TO SLOWLY TRACK THROUGH  
LOWER ID PANHANDLE INTO MT DURING THIS PERIOD. BANDS OF WRAP  
AROUND MOISTURE WILL BRING WIDESPREAD RAINSHOWERS TO THE REGION  
ESPECIALLY THE ID PANHANDLE AND NE WA. THESE SHOWERS COULD BE  
MODERATE AT TIMES WITH 12 HOUR RAINFALL AMOUNTS AROUND THE HALF  
AN INCH RANGE. THE REST OF THE REGION CAN EXPECT TO RECEIVE UP TO  
THREE TENTHS OF AN INCH PER 12 HOURS. A LOOSENED GRADIENT IN THE  
REGION IS EXPECTED TO BRING WEAKER WINDS BUT GUSTS IN THE 20MPH  
ARE STILL POSSIBLE. TEMPERATURES WILL STILL BE IMPACTED BY THE  
DECENT CLOUD COVER. HIGHS WILL BE IN THE 50S TO LOW 60S. LOWS WILL  
RANGE IN THE 40S.  
 
TUESDAY THROUGH THURSDAY: BY TUESDAY, THE LOW IS WELL EAST OF THE  
REGION AND A RIDGE IS BUILDING ALONG THE COAST. THIS WILL LEAD TO  
A DRYING TREND WITH SHOWERS TAPERING OFF OVER ID. THE REST OF THE  
PERIOD IS EXPECTED TO DRY WITH A WARMING TREND AS THE RIDGE  
STRENGTHENS AND MOVES OVER WASHINGTON. TEMPERATES WILL ARE  
EXPECTED TO CLIMB BACK INTO THE 70S AND LOW 80 BY END THE OF THE  
PERIOD. LOWS WILL BE SLIGHTLY COOLER DUE TO RADIATIONAL COOLING  
AND RANGE IN UPPER 30S TO MID 40S. /JDC  
 

 
   
AVIATION
 
 
12Z TAFS: CLEAR SKIES WITH VFR CONDITIONS WILL CONTINUE AT ALL  
TAF SITES THROUGH 12Z FRIDAY UNDER LIGHT WINDS. /RFOX  
 

 
   
PRELIMINARY POINT TEMPS/POPS
 
 
SPOKANE 76 49 80 47 58 42 / 0 0 0 20 60 50  
COEUR D'ALENE 76 46 80 47 57 42 / 0 0 0 10 40 70  
PULLMAN 76 46 79 46 56 42 / 0 0 0 30 60 60  
LEWISTON 82 50 84 52 62 47 / 0 0 0 30 60 50  
COLVILLE 79 46 82 49 64 48 / 0 0 0 10 70 60  
SANDPOINT 74 42 78 46 60 44 / 0 0 0 10 30 60  
KELLOGG 76 44 78 44 59 40 / 0 0 0 10 30 70  
MOSES LAKE 82 46 84 50 64 45 / 0 0 0 30 60 20  
WENATCHEE 80 51 82 51 64 45 / 0 0 0 20 60 20  
OMAK 80 49 83 52 67 48 / 0 0 0 10 70 40  
 

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

 
 

 
 
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