493  
FXUS65 KMSO 302040  
AFDMSO  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE MISSOULA MT  
240 PM MDT SAT MAY 30 2020  
   
DISCUSSION
 
WE CURRENTLY HAVE ABUNDANT AVAILABLE MOISTURE IN  
THE REGION WITH DEW POINTS IN THE 50S. ALONG WITH ABOVE-AVERAGE  
TEMPERATURES, THESE CONDITIONS POINT TO VERY UNSTABLE CONDITIONS  
BY THIS EVENING. SPOKES OF ENERGY ASSOCIATED WITH A LOW PRESSURE  
CIRCULATION TO THE WEST ARE MOVING INTO THE REGION TODAY. THIS  
ENERGY WILL BE THE FOCUSING MECHANISM FOR POTENTIALLY STRONG  
THUNDERSTORMS. MUCH OF THE STORM ACTIVITY IS MOST LIKELY TO BE  
LATE TODAY AND TONIGHT IN NORTH-CENTRAL IDAHO AND WESTERN MONTANA,  
BUT SPOTS THAT HAVE ADDED UPPER LEVEL SUPPORT WILL SEE  
THUNDERSTORMS DURING THIS EVENING. STORMS ARE CURRENTLY FORECAST  
TO INITIATE IN THE BITTERROOT AND SAPPHIRE MOUNTAINS AND THE  
BITTERROOT VALLEY THIS AFTERNOON AND MOVE OFF TO THE NORTHEAST,  
POSSIBLY AFFECTING MISSOULA DURING THE EARLY EVENING. LATEST  
PROJECTIONS SHOW THE STRONGEST STORMS OCCURRING OVERNIGHT IN IDAHO  
AND CLEARWATER COUNTIES AND INTO NORTHWEST MONTANA.  
 
WIDESPREAD SHOWERS AND THUNDERSTORMS ARE EXPECTED STARTING EARLY  
SUNDAY MORNING, MAINLY FOCUSED IN NORTH-CENTRAL IDAHO AND  
NORTHWEST MONTANA THROUGH SUNDAY MORNING. SHOWER CHANCES WILL  
LINGER INTO SUNDAY AFTERNOON WITH TEMPERATURES AROUND 20 DEGREES  
COOLER THAN TODAY WITH BREEZY WINDS.  
 
MONDAY LOOKS TO HAVE ABOVE NORMAL TEMPERATURES AND CHANCES FOR  
SHOWERS AND THUNDERSTORMS DUE TO A SHORTWAVE TROUGH PASSAGE.  
 
PERIODIC SHOWERS ARE POSSIBLE FOR THE SECOND HALF OF THE WEEK AS  
THE FLOW PATTERN SHIFTS FROM WESTERLY TO SOUTHWESTERLY.  
 

 
   
AVIATION
 
INGREDIENTS ARE LINING UP WELL FOR SOME THUNDERSTORMS  
THIS AFTERNOON AND EVENING. AMPLE INSTABILITY AND SHEAR WILL FUEL  
THESE STORMS INTO TONIGHT ACROSS THE NORTHERN ROCKIES. ONE  
WILDCARD IS THE PRESENCE OF A CAPPING INVERSION. THIS COULD  
SUPPRESS CONVECTION, OR MAKE IT MORE INTENSE IF THE CAP IS BROKEN.  
THE FORECAST CHALLENGE IS PINPOINTING EXACTLY WHEN AND WHERE  
CONVECTION WILL OCCUR. WHERE IT DOES OCCUR, STORMS WILL BRING  
SMALL HAIL, GUSTY WINDS, AND LIGHTNING. A MENTION OF  
THUNDERSTORMS STARTING THIS AFTERNOON ARE IN TAFS AT KGPI, KMSO,  
AND KBTM. ACTIVITY WILL START IN THE SOUTH AND MOVE NORTH, SO KGPI  
MIGHT NOT SEE ANYTHING UNTIL AROUND 31/0500Z. ON SUNDAY, A FAST-  
MOVING SHORTWAVE TROUGH WILL BRING MORE WIDESPREAD SHOWERS. AN  
ASSOCIATED COLD FRONT WILL ADD GUSTY WINDS TO ALL TERMINALS AFTER  
NOON.  
 

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

 
 

 
 
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