271  
FXUS65 KBYZ 220319  
AFDBYZ  
 
AREA FORECAST DISCUSSION...UPDATED  
NATIONAL WEATHER SERVICE BILLINGS MT  
919 PM MDT SAT APR 21 2018  
   
UPDATE
 
 
WEAK, DRY COLD FRONT HAS MADE IT THROUGH THE NORTHWESTERN ZONES  
THIS EVENING. WINDS HAVE BEEN GUSTY AT JUDITH GAP...BUT EXPECT  
THESE WINDS TO DECREASE IN THE NEXT FEW HOURS THERE AS PRESSURE  
GRADIENT CHANGES DIRECTION AND WEAKENS. THE FRONT SHOULD CROSS  
BILLINGS AROUND OR JUST BEFORE 10 PM MDT AND SHERIDAN BY 1 AM MDT  
OR SO, MARKED BY WINDS SWITCHING TO NORTH/NORTHWESTERLY AND WIND  
SPEEDS INCREASING TO ABOUT 15 MPH, GUSTING TO 20-25 MPH FOR A FEW  
HOURS. HAVE KEPT A SLIGHT CHANCE OF A RAIN/SNOW SHOWER OVER THE  
BEARTOOTH/ABSAROKA AND BIGHORN MOUNTAINS AS WINDS CAN UPSLOPE  
THERE BEHIND THE FRONT. CURRENT FORECAST HAS ALL OF THIS COVERED.  
RMS/BORSUM  
 

 
   
SHORT TERM...VALID FOR SUN AND MON
 
 
LITTLE IN THE WAY OF CHANGES TO THE INHERITED FORECAST THIS  
AFTERNOON, AS MODELS REMAIN CONSISTENT WITH REGARD TO COLD FRONT  
TONIGHT, AND ANOTHER DISTURBANCE ACROSS THE REGION MONDAY.  
 
A MAINLY DRY COLD FRONT ACROSS OUR REGION LATE THIS EVENING AND  
OVERNIGHT. THE FRONT WILL BRING A PERIOD OF GUSTY WINDS, BUT WITH  
LITTLE MOISTURE OR UPPER LEVEL SUPPORT, LITTLE OR NO PRECIP IS  
EXPECTED. CONTINUE TO CARRY LOW POP'S ALONG THE  
BEARTOOTHS/PRYORS/BIGHORNS AND NEARBY FOOTHILLS, AS OROGRAPHICS  
COULD BE ENOUGH FOR A FEW SHOWERS.  
 
EASTERLY WINDS AND SOME CLOUD COVER SUNDAY POINT TO COOLER TEMPS,  
BUT STILL SEASONAL, WITH UPPER 50S TO LOWER 60S. THAT SAID,  
EXPECT INCREASING CLOUD COVER AND SCATTERED RAIN AND HIGH  
ELEVATIONS SNOW SHOWERS DEVELOPING LATE IN THE DAY AS A TROUGH  
MOVES INTO THE INNER NORTHERN ROCKIES. THIS SYSTEM IS PROGGED TO  
TRACK RIGHT OVER OUR CWA LATE SUNDAY NIGHT THROUGH LATE MONDAY  
NIGHT, SPREADING PRECIP FROM WEST TO EAST. SEVERAL INCHES OF WET  
SNOW ARE POSSIBLE IN THE HIGH COUNTRY WITH SOME ACCUMULATION ALSO  
POSSIBLE IN THE FOOTHILLS BY MONDAY MORNING.  
 
THE SYSTEM WILL LEAD TO A VERY WET AND COOL MONDAY ACROSS THE  
REGION. PRECIP IN THE PLAINS WILL BE MAINLY RAIN, BUT MIXED PRECIP  
CANNOT BE COMPLETELY RULED OUT. PRECIP IS EXPECTED TO SWITCH TO  
SNOW OVERNIGHT MONDAY NIGHT, WITH GREATEST IMPACTS IN EASTERN  
ZONES, WHERE ACCUMULATIONS ON COOLER MONDAY NIGHT MAY ALLOW FOR  
SOME ACCUMULATIONS. TIMING OF THIS SYSTEM EXITING THE REGION  
REMAINS A BIT UNCERTAIN, WITH GFS MUCH QUICKER, WHICH WOULD CUT  
BACK SIGNIFICANTLY ON POSSIBLE SNOW ACCUMULATIONS IN THE  
SOUTHEAST. HAVE NOT ISSUED ANY HIGHLIGHTS AT THIS TIME DUE TO  
TIMING OF PRECIP ACROSS THE AREA BEING MAINLY DURING THE DAY  
MONDAY. THIS SYSTEM CONTINUES TO NEED ATTENTION, AS IT CROSSES THE  
REGION, IF ONLY FOR TIMING, TO BETTER ESTIMATE POSSIBLE SNOW. AAG  
 
   
LONG TERM...VALID FOR TUE...WED...THU...FRI...SAT
 
 
MONDAYS STORM SYSTEM MOVES OUT INTO THE NORTHERN AND CENTRAL  
PLAINS DURING THE DAY TUESDAY. A FEW LEFTOVER RAIN AND SNOW  
SHOWERS WILL BE POSSIBLE DURING THE DAY ACROSS SOUTHEAST CARTER  
COUNTY. OTHERWISE, THE FORECAST AREA LOOKS TO DRY OUT. AT THIS  
TIME, IT LOOKS TO BE A QUIET EXTENDED FORECAST. A CLIPPER TYPE  
SYSTEM DROPS SOUTHEAST OUT OF CANADA ACROSS THE EASTERN HALF OF  
MONTANA LATE WEDNESDAY BUT RIGHT NOW MODELS SHOW LITTLE IF ANY  
MOISTURE WITH IT. HIGH PRESSURE RIDGING BUILDS IN FOR LATE TUESDAY  
AND AGAIN THURSDAY INTO SATURDAY. MODELS BRING A CUTOFF LOW ONTO  
THE CALIFORNIA COAST BY THE END OF THE WEEK KEEPING A SPLIT FLOW  
ALOFT TO RIDGING OVER OUR FORECAST AREA. TEMPERATURES WILL BE  
AROUND NORMAL TUESDAY WITH READINGS ABOVE NORMAL FOR THE REMAINDER  
OF THE WEEK. HOOLEY  

 
   
AVIATION
 
 
A FEW HIGH CLOUDS WILL MOVE ACROSS THE AREA BUT VFR CONDITIONS  
WILL PREVAIL. BORSUM  
 

 
   
PRELIMINARY POINT TEMP/POPS
 
 
SUN MON TUE WED THU FRI SAT  
-----------------------------------------------------------  
BIL 041/062 037/046 031/058 035/066 036/062 038/069 038/065  
10/B 69/O 30/U 01/U 21/U 00/U 11/U  
LVM 036/062 034/043 023/057 031/063 033/062 035/066 035/063  
12/W 99/O 20/U 01/B 21/U 01/U 12/W  
HDN 038/065 037/046 030/057 032/065 035/061 036/069 037/065  
10/B 59/O 30/U 01/U 21/U 00/U 01/U  
MLS 042/065 038/046 031/058 035/064 035/060 036/066 037/065  
00/B 58/O 40/U 00/U 10/U 00/U 00/U  
4BQ 038/063 039/046 031/055 034/064 034/057 036/064 036/063  
00/B 29/R 70/B 00/U 11/U 00/U 00/U  
BHK 035/059 038/044 031/053 032/061 036/055 036/062 034/060  
00/B 17/R 60/B 00/U 10/U 00/U 00/U  
SHR 037/065 036/044 028/056 030/065 033/058 035/067 035/065  
00/U 39/R 51/B 01/U 21/B 01/U 11/U  
 

 
   
BYZ WATCHES/WARNINGS/ADVISORIES
 
 
MT...NONE.  
WY...NONE.  
 

 
 

 
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