061  
FXUS66 KOTX 261229  
AFDOTX  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE SPOKANE WA  
529 AM PDT WED APR 26 2017  
   
SYNOPSIS
 
 
EXPECT COOL, BREEZY, AND SHOWERY WEATHER FOR THE REST OF THIS  
WEEK. SHOWERS WILL BE MOST NUMEROUS TODAY WITH ISOLATED  
THUNDERSTORMS POSSIBLE OVER THE NORTHERN MOUNTAINS. MOUNTAIN  
PASSES COULD SEE A FEW INCHES OF SNOW OVERNIGHT WEDNESDAY INTO  
THURSDAY MORNING. A RIDGE OF HIGH PRESSURE MOVES IN SATURDAY  
DELIVERING A BRIEF DRY PERIOD BEFORE MORE UNSETTLED WEATHER MOVES  
IN SUNDAY AND INTO EARLY NEXT WEEK.  
 

 
   
DISCUSSION
 
 
TODAY THROUGH THURSDAY: AN OCCLUDED FRONT IS PUSHING ACROSS THE  
REGION AT 200 AM THIS MORNING. LIGHT RAIN AND HIGH MOUNTAIN SNOW  
ABOVE 5000 FEET IS EXPECTED WITH THIS FEATURE THROUGH THIS MORNING  
AND MAINLY OVER THE PANHANDLE BY 700 AM. THERE IS ANOTHER WAVE  
BEHIND THIS FRONT THAT IS CURRENTLY JUST BEGINNING TO MOVE INTO  
WESTERN OR. LATEST MODEL RUNS CONTINUE TO HAVE THE MOISTURE  
ASSOCIATED WITH THIS SECOND WAVE FURTHER SOUTH THAN PREVIOUSLY  
THOUGHT. IT IS LOOKING MORE AND MORE LIKE THE BULK OF THE PRECIP  
WILL REMAIN OVER OR AND INTO SOUTHERN ID. WE WILL MAINLY JUST GET  
HIT BY THE NORTHERN FRINGE ON WEDNESDAY FROM THE NORTHEAST BLUE  
MTNS TO THE CAMAS PRAIRIE. HOWEVER, THIS DOESN'T MEAN THAT THE  
REST OF THE REGION WILL BE DRY TODAY. THERE IS A GOOD POSSIBILITY  
FOR MID LEVEL CLOUDS TO BREAK UP ACROSS THE NORTHERN PORTIONS OF  
THE REGION TO ALLOW JUST ENOUGH SURFACE HEATING TO DESTABILIZE THE  
ATMOSPHERE FOR THE AFTERNOON. THE BULK OF THE SHOWER ACTIVITY, AT  
LEAST A THE START OF THE AFTERNOON, WILL BE OVER THE OKANOGAN  
HIGHLANDS TO THE NORTHERN PANHANDLE. THERE WILL BE WEAK SURFACE  
BASED CAPE, BUT I DO THINK WE WILL SEE ENOUGH CHARGE SEPARATION  
FOR ISOLATED THUNDERSTORMS WITH THE SHOWERS OVER THE NORTHERN MTNS.  
THIS CONVECTION MAY THEN MIGRATE FURTHER SOUTH ACROSS THE  
SPOKANE-COEUR D'ALENE CORRIDOR BY THE LATE AFTERNOON OR EARLY  
EVENING HOURS. WINDS WILL BE BREEZY TODAY AS WELL WITH STRONGEST  
WINDS FUNNELING OUT OF THE WENATCHEE RIVER VALLEY, MOSES LAKE AREA  
AND OVER INTO THE PALOUSE. EXPECT WIND GUSTS IN THE 30-40 MPH  
RANGE ACROSS THESE AREAS.  
 
SNOW LEVELS WILL DROP OVERNIGHT DOWN TO AROUND 3000 FEET. THE  
COOLER AIR WILL BRING A CHANCE FOR ACCUMULATING SNOW OVER STEVENS  
PASS AND LOOKOUT PASS. HIGHER RESOLUTION MODELS INDICATE A PUGET  
SOUND CONVERGENCE ZONE (PSCZ) SETTING UP OVER THE NORTHERN  
CASCADES AND COULD LINE UP OVER STEVENS PASS. THIS FEATURE  
TYPICALLY WILL BRING A NARROW SWATH OF INTENSE PRECIP. IT'S  
POSSIBLE THAT THE PRECIP TURNS OVER TO SNOW AT STEVENS PASS BY  
LATE AFTERNOON WITH HEAVY ACCUMULATIONS FOR THE EVENING.  
CONFIDENCE IS LOW, HOWEVER, SINCE IT IS DIFFICULT TO KNOW WHERE  
THIS CONVERGENCE ZONE WILL SET UP. THE SNOW SHOWERS ARE EXPECTED  
TO BE LIGHTER OVER LOOKOUT PASS, BUT MAY RESULT IN 1-3 INCHES OF  
SNOW BY THURSDAY MORNING.  
 
THE ATMOSPHERE WILL REMAIN CONDITIONALLY UNSTABLE FOR THURSDAY. WE  
DON'T LOOK TO BE AS UNSTABLE AS TODAY WITH DEW POINT TEMPERATURES  
A BIT COOLER. BEST CHANCES FOR SHOWERS WILL BE OVER THE EASTERN  
HALF OF THE FORECAST AREA WITH GRAUPLE POSSIBLE UNDER STRONGER  
SHOWERS. /SVH  
 
THURSDAY NIGHT AND FRIDAY...THE UPPER LEVEL STEERING FLOW WILL  
TRANSITION FROM NORTHWEST THURSDAY NIGHT TO NORTHERLY BY FRIDAY  
AS AN UPPER LEVEL LOW SHIFTS TO THE EAST AND HIGH PRESSURE BEGINS  
TO PUSH INLAND ON FRIDAY. MODEL GUIDANCE IS SIMILAR AND HAS BEEN  
CONSISTENT SHOWING SEVERAL WEAK WAVES DROPPING THROUGH THE REGION  
ON THE BACKSIDE OF THE EXITING TROUGH. THE WAVES WHEN COMBINED  
WITH WEAK INSTABILITY AND OROGRAPHIC LIFT WILL RESULT IN A GOOD  
SET UP FOR SHOWERS THROUGH SUNSET FRIDAY EVENING. THE ONLY THING  
LACKING IS A DECENT MOISTURE SOURCE. THERE WILL STILL BE A CHANCE  
TO SEE LOCALIZED MODERATE TO HEAVY SHOWERS LATE IN THE DAY ACROSS  
NORTHEAST WASHINGTON AND THE IDAHO PANHANDLE. GUIDANCE SHOWS A  
BULLS EYE OF BETWEEN A QUARTER TO A HALF INCH OVER THE NORTH  
PANHANDLE. OTHERWISE PRECIPITATION AMOUNTS WILL BE BETWEEN A TENTH  
AND A QUARTER OF AN INCH. BECAUSE WE WILL BE ON THE COOL SIDE OF  
THE JET SNOW LEVELS WILL RANGE FROM 3500-4500 AND 2-13 INCHES OF  
NEW SNOW WILL BE POSSIBLE FOR THE CENTRAL MOUNTAINS. WITH MORE  
SUNSHINE AND SLIGHTLY WARMER 850 TEMPERATURES AFTERNOON HIGHS WILL  
BE 3-4 DEGREES WARMER THEN ON THURSDAY.  
 
FRIDAY NIGHT THROUGH SATURDAY...THE RIDGE WILL NOSE INTO THE REGION  
FRIDAY NIGHT FOR A DAY OF MOSTLY DRY WEATHER. TEMPERATURES WILL  
BE ON THE RISE. WITH HIGHS IN THE MID 50S TO MID 60S. BY LATE IN  
THE DAY SATURDAY CLOUDS WILL BE ON THE INCREASE AS ANOTHER UPPER  
LEVEL LOW MOVES THROUGH B.C. AND BENDS DOWN THE LOW. SOME LOW END  
CHANCE POPS WERE KEPT IN THE FORECAST FOR THE NORTHEAST WASHINGTON  
MOUNTAINS AND THE NORTH PANHANDLE MOUNTAINS, WITH ANY  
ACCUMULATIONS BEING LIGHT.  
 
SATURDAY NIGHT THROUGH SUNDAY NIGHT...THE CHANCES FOR  
PRECIPITATION WILL INCREASE SATURDAY NIGHT THROUGH SUNDAY AS THE  
AFOREMENTIONED LOW DRAGS A WARM FRONT THROUGH THE REGION. MODELS  
START TO SHOW SOME DIFFERENCES ON TIMING AND CHOSE TO LEAN TOWARDS  
THE SLOWER AND DRIER EC/CANADIAN AS COMPARED TO THE WETTER GFS. A  
FAIRLY STRONG, FOR THE SEASON, WARM FRONT WILL TRACK ACROSS THE  
REGION AND WITH AVAILABLE MOISTURE INCREASING TO ABOUT 200 PERCENT  
OF NORMAL WILL RESULT IN ANOTHER ROUND OF WIDESPREAD SHOWERS FOR  
MOST AREAS OUTSIDE OF THE COLUMBIA BASIN. PRECIPITATION AMOUNTS  
FOR MOST PLACES THAT SEE RAIN WILL BE UNDER A TENTH OF AN INCH,  
HOWEVER ALONG THE CASCADE CREST AND THE PANHANDLE MOUNTAINS A FEW  
LOCATIONS MAY SEE UP TO A HALF INCH. SNOW LEVELS WILL BE AROUND  
5500 FEET SO ONLY THE HIGHEST PEAKS WILL SEE MEASURABLE SNOW. YET  
ANOTHER QUICK HITTING SHORT WAVE DISTURBANCE WILL BE POSSIBLE  
EARLY MONDAY MORNING TO KEEP SHOWERS IN THE FORECAST. BUT ALL IS  
NOT LOST IT DOES LOOK LIKE THERE WILL BE A WARMING TREND BY MID  
WEEK. TOBIN  
 
MONDAY THROUGH WEDNESDAY: MONDAY THE MODELS DIVERGE ON THE THE  
EVOLUTION OF THE RIDGE THAT BEGINS TO BUILD IN DURING THE FIRST  
HALF OF THE WEEK. THE GFS DROPS A DISTURBANCE THROUGH ON MONDAY  
KEEPING BETTER RAIN CHANCES IN THE FORECAST, WHILE THE EC AND  
CANADIAN BEGINS TO BUILD IN THE RIDGE WITH ONLY SCATTERED SHOWERS.  
FOR NOW, WILL KEEP SOME RAIN CHANCES AROUND, MOSTLY OUTSIDE OF THE  
BASIN ON MONDAY. THE BEST CHANCE WILL BE FOR THE PANHANDLE  
MOUNTAINS. BEYOND MONDAY MODELS ARE IN QUITE GOOD AGREEMENT THAT  
AN UPPER RIDGE WILL BUILD IN FOR THE MIDDLE OF THE WEEK. THIS WILL  
BRING DRY CONDITIONS AND WARMER TEMPERATURES, CLOSER TO AVERAGE BY  
WEDNESDAY. IF MODELS CONTINUE THEIR TREND, THIS RIDGE COULD BRING  
US THE WARMEST TEMPERATURES OF THE YEAR LATE IN THE WEEK. /BW  
 

 
   
AVIATION
 
 
12Z TAFS: A FRONTAL BAND WILL SPREAD LIGHT TO MODERATE RAIN  
THROUGH THE EARLY MORNING EAST OF A LINE FROM KOMK TO KALW. THE  
ADDED RAINFALL WILL KEEP THE BOUNDARY LAYER MOIST WITH MVFR/IFR  
CONDITIONS PERSISTING AT KGEG, KSFF, KCOE AND KPUW THROUGH MUCH OF  
THIS MORNING. A STRONGER DISTURBANCE WILL PUSH EAST OF THE  
CASCADE MTNS THIS AFTERNOON. THE BULK OF THE MOISTURE WITH THIS  
WAVE WILL REMAIN ACROSS OREGON, BUT THE NORTHERN FRINGE WILL  
IMPACT KPUW AND KLWS AFTER 19Z INTO THE EARLY EVENING. MVFR CIGS  
WILL BE POSSIBLE THROUGH THE AFTERNOON AT KPUW. THE ATMOSPHERE  
WILL DESTABILIZE ACROSS THE NORTHERN MTNS THIS AFTERNOON WITH  
NUMEROUS SHOWERS AND ISOLATED THUNDERSTORMS POSSIBLE WITH  
CONVECTION IMPACTING THE SPOKANE/COEUR D'ALENE CORRIDOR BY THE  
LATE AFTERNOON HOURS. IN ADDITION, WINDS WILL BE BREEZY THIS  
AFTERNOON, ESPECIALLY AT KEAT WITH GUSTS UP TO AROUND 35 KTS BY  
THE LATE AFTERNOON HOURS. /SVH  
 

 
   
PRELIMINARY POINT TEMPS/POPS
 
 
SPOKANE 54 36 51 36 54 37 / 60 40 40 20 30 20  
COEUR D'ALENE 52 35 49 35 52 34 / 100 40 70 40 30 20  
PULLMAN 52 37 50 36 52 36 / 90 50 40 20 30 10  
LEWISTON 57 41 55 39 57 39 / 70 30 30 20 20 10  
COLVILLE 52 37 52 37 57 36 / 90 70 40 10 30 10  
SANDPOINT 50 36 47 36 50 34 / 100 90 80 50 40 50  
KELLOGG 47 35 43 34 46 33 / 100 70 70 60 40 20  
MOSES LAKE 62 40 61 38 62 37 / 10 0 10 0 10 0  
WENATCHEE 59 39 58 39 60 38 / 0 0 0 0 10 0  
OMAK 61 38 59 38 62 37 / 30 0 10 10 20 10  
 

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

 
 

 
 
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