422  
FXUS65 KMSO 242024  
AFDMSO  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE MISSOULA MT  
224 PM MDT FRI MAR 24 2017  
   
DISCUSSION
 
A WEATHER SYSTEM AND ASSOCIATED COLD FRONT WILL  
SWEEP ACROSS NORTH CENTRAL IDAHO EARLY THIS EVENING AND WESTERN  
MONTANA OVERNIGHT. INITIALLY, THE SNOW LEVEL IS ABOVE MOST  
MOUNTAIN PASSES, BUT WILL LOWER OVERNIGHT WITH MAINLY LOLO, LOST  
TRAIL, WILLIAM'S SUMMIT, AND POSSIBLY HOMESTAKE SEEING SOME SNOW.  
THE IMPACT SHOULD BE A SHORT PERIOD OF SLUSH OR WET SNOW ON THE  
ROADWAY LATER TONIGHT AND EARLY SATURDAY MORNING. OTHERWISE, RAIN  
SHOWERS SHOULD BE ON THE LIGHT TO MODERATE SIDE WITH LITTLE OR NO  
ADDITIONAL RUNOFF.  
 
A RELATIVELY COOL AND BREEZY PERIOD IS EXPECTED SATURDAY AS A  
MOIST AND UNSTABLE ATMOSPHERE COVERS THE NORTHERN ROCKIES.  
 
SUNDAY BRINGS WEAK HIGH PRESSURE AND A DRY PERIOD WITH SEASONAL  
HIGH TEMPERATURES INTO THE 50S. THE RIDGE ALOFT COULD ALLOW FOR  
SOME PATCHY FOG DURING THE EARLY MORNING HOURS, BUT HEATING AFTER  
SUNRISE WOULD QUICKLY MIX OUT FOG THAT DOES FORM.  
 
SUNDAY NIGHT INTO MONDAY MORNING, ANOTHER WET SYSTEM WILL MOVE  
OVER THE REGION. THE MAIN ENERGY WITH THIS TROUGH WILL BE TO THE  
SOUTH, SO PRECIPITATION RATES AND ACCUMULATION WILL AGAIN BE ON  
THE LIGHT SIDE. HOWEVER, CLEARWATER AND IDAHO COUNTY COULD SEE  
ANOTHER 0.25 TO 0.50 INCHES OF MOISTURE OVER 24 HOURS, SO  
SATURATED SOILS COULD AGAIN BECOME MORE PRONE TO ISOLATED MUD AND  
ROCKSLIDES. SCATTERED SHOWERS, MAINLY IN THE TERRAIN, LINGER ON  
TUESDAY AND WEDNESDAY IN WESTERLY FLOW.  
 
A MORE ROBUST SYSTEM COULD BRING HEAVIER RAIN AMOUNTS ON  
WEDNESDAY NIGHT. MODELS ADVERTISE A SHORT BURST OF PACIFIC  
MOISTURE BEFORE A SHORTWAVE TROUGH MOVES THROUGH THURSDAY. BUT  
THESE TYPE OF SYSTEMS HAVE TRENDED SOUTH IN RECENT WEEKS, SO THE  
CONFIDENCE IN PRECIPITATION AMOUNTS IS LOW AT THIS TIME.  
 

 
   
AVIATION
 
THE NORTHERN ROCKIES WILL SEE THICKENING CLOUDS AND  
LOWERING CEILINGS INTO THE EVENING AS THE NEXT WEATHER SYSTEM  
APPROACHES. NORTH CENTRAL IDAHO WILL SEE LIGHT TO MODERATE RAIN  
SHOWERS FIRST, INTO THIS EVENING. WESTERN MONTANA AVIATION SITES  
KMSO AND KGPI SHOULD SEE SHOWERS THIS EVENING AND OVERNIGHT. THE  
FRONTAL/WEATHER SYSTEM WILL NOT IMPACT KBTM WITH SHOWERS UNTIL  
AROUND OR AFTER MIDNIGHT. THE MAIN IMPACTS OF THE SHOWERS SHOULD  
BE LOWERING OF CEILINGS AND VISIBILITY IN THE MORE MODERATE  
PRECIPITATION SHOWERS AND INCREASING TERRAIN OBSCURATIONS.  
SOUTHWESTERLY BREEZES OF 20-30 KTS AHEAD OF THE SHOWERS CAN BE  
EXPECTED FOR KBTM INTO THIS EVENING.  
 

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

 
 

 
 
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