089  
FXUS65 KMSO 260946  
AFDMSO  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE MISSOULA MT  
346 AM MDT WED APR 26 2017  
   
DISCUSSION
 
THE FIRST WAVE OF PRECIPITATION WITH TODAY'S SYSTEM HAS  
ALREADY ARRIVED OVER NORTH CENTRAL IDAHO, AND WILL CONTINUE TO  
MOVE EAST THIS MORNING. EXPECT A WET AND COOL DAY, WITH ABUNDANT  
CLOUD COVER AND RAIN BELOW 5000 TO 6000 FT. TEMPERATURES TODAY  
AND THURSDAY WILL RUN ABOUT 10 DEGREES BELOW AVERAGE AS A TROUGH  
SETS UP OVER THE NORTHERN ROCKIES.  
 
AFTER TODAY'S RAIN, A REINFORCING SHOT OF COOLER AIR WILL MOVE IN  
FROM THE NORTHWEST, BRINGING SNOW SHOWERS DURING THURSDAY MORNING  
FOR LOCATIONS ABOVE 3000 TO 3500 FT. WARM GROUND TEMPERATURES  
WILL LIKELY HELP IN QUICKLY MELTING SNOWFALL, BUT MOUNTAIN PASSES  
SUCH AS LOOKOUT, LOLO, LOST TRAIL, MARIAS, AND HOMESTAKE WILL  
LIKELY SEE PERIODS OF SNOW-COVERED ROADS DURING SHOWERS. EVEN ON  
PASSES, AMOUNTS SHOULD BE LIMITED TO A FEW SLUSHY INCHES, BUT  
TRAVELERS WILL STILL WANT TO LEAVE A LITTLE EXTRA TIME TO  
NAVIGATE IN THE WINTER DRIVING CONDITIONS. AFTER DAYBREAK  
THURSDAY, DAYTIME HEATING WILL MAKE IT EVEN HARDER FOR SNOW TO  
STICK. A REPEAT OF THIS SITUATION WILL OCCUR THURSDAY NIGHT INTO  
FRIDAY MORNING, AS SHOWERS CONTINUE AND SNOW LEVELS REMAIN LOW IN  
THE 3000 FT RANGE.  
 
DURING THE AFTERNOONS ON THURSDAY AND FRIDAY, VALLEYS WILL HAVE  
HIGH CHANCES TO SEE OCCASIONAL RAIN & SNOW AS SHOWERS DRIFT  
OVERHEAD, BUT PRECIPITATION WILL NOT BE CONTINUOUS. COOL AND  
MOSTLY CLOUDY WILL BE THE TREND, SIMILAR TO MOST DAYS THE PREVIOUS  
WEEK.  
 
A BRIEF DRIER PERIOD IS STILL IN THE FORECAST FOR SATURDAY; WHILE  
NOT A COMPLETELY DRY DAY, SATURDAY REMAINS THE DAY WHERE THERE  
WILL BE THE MOST BREAKS BETWEEN SHOWERS. A TROUGH PASSAGE ON  
SUNDAY HAS A FAIRLY HIGH POTENTIAL TO BRING WIDESPREAD  
PRECIPITATION BUT THE STRENGTH AND AMOUNT OF PRECIPITATION IS  
STILL IN QUESTION.  
 
THE COOL AND SHOWERY PATTERN LOOKS TO REMAIN FOR THE BEGINNING OF  
NEXT WEEK, BUT THE ABERRANT RIDGE OF HIGH PRESSURE MAY START  
SHOWING SIGNS OF BUILDING INTO THE REGION AROUND THE MIDDLE OF  
NEXT WEEK.  
 

 
   
AVIATION
 
RADAR CURRENTLY SHOWS RAIN SPREADING OVER THE NORTHERN  
ROCKIES FROM THE WEST. PERIODS OF RAIN WILL LAST THROUGH A  
MAJORITY OF THE DAY, WITH ALL TERMINALS SEEING NEARLY CONTINUOUS  
VICINITY SHOWERS, ALONG WITH OFF-AND-ON SHOWERS OVERHEAD.  
PRECIPITATION WILL BE MORE SPOTTY OVER SOUTHWEST MONTANA AND  
LEMHI COUNTY, BUT EVEN THESE DRIER LOCATIONS WILL LIKELY PICK UP A  
FEW TENTHS OF AN INCH OF RAIN. SITES ABOVE 5000 FT LIKE KBTM COULD  
SEE PRECIPITATION FALL AS SNOW SHOWERS UNTIL NOON. ISOLATED  
THUNDERSTORMS ARE POSSIBLE THIS AFTERNOON WITH ENHANCED LIFT FROM  
AN INCOMING SHORTWAVE TROUGH. PRECIPITATION INTENSITY AND COVERAGE  
DECREASES AFTER 27/0300Z, BUT SHOWERS WILL REMAIN INTO THURSDAY.  
 

 
   
MSO WATCHES/WARNINGS/ADVISORIES
 
 
MT...NONE.  
ID...NONE.  

 
 

 
 
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