399  
FXUS63 KUNR 221133  
AFDUNR  
 
AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY  
NATIONAL WEATHER SERVICE RAPID CITY SD  
433 AM MST TUE JAN 22 2019  
   
UPDATE
 
 
ISSUED AT 401 AM MST TUE JAN 22 2019  
 
REMAINING HEADLINES HAVE BEEN DROPPED AS CONDITIONS CONTINUE TO  
IMPROVE.  
 

 
   
DISCUSSION
 
(TODAY THROUGH MONDAY)  
ISSUED AT 235 AM MST TUE JAN 22 2019  
 
CURRENT SURFACE MAP PLACES LOW OVER EASTERN COLORADO WITH INVERTED  
TROF INTO CENTRAL SOUTH DAKOTA. UPPER TROF CROSSING THE CENTRAL  
ROCKIES, WITH BEST Q-G FORCING SOUTH OF THE FORECAST AREA. AS A  
RESULT, RADAR TRENDS SHOW DECREASING COVERAGE OF SNOW OVER THE  
FORECAST AREA. WINDS ALSO DECREASING AS THE BEST PRESSURE RISES  
SHIFT SOUTH OF THE AREA. WITH IMPROVING CONDITIONS, HAVE DROPPED  
SOME OF THE WARNING/ADVISORY AREA...WITH REMAINING AREAS PROBABLY  
CANCELLED IN THE NEXT FEW HOURS.  
 
NORTHWEST FLOW SETS UP ACROSS THE AREA FOR THE LAST HALF OF THE  
WEEK INTO EARLY NEXT WEEK WITH AMPLIFICATION OF WEST COAST RIDGE  
AND HUDSON BAY LOW. SEVERAL CLIPPER SYSTEMS WILL SWING THROUGH THE  
CANADIAN ROCKIES INTO THE GREAT LAKES REGION. TEMPERATURES WILL  
OSCILLATE WITH EACH SYSTEM; BRIEF WARM UP AHEAD OF EACH CLIPPER  
FOLLOWED BY SURGE OF ARCTIC AIR. EACH ARCTIC FRONT WILL RESULT IN  
SOME WIDESPREAD LIGHT SNOW ACROSS THE AREA ALONG WITH BREEZY  
NORTHWEST WINDS. LOW CONFIDENCE IN TEMPERATURE FORECAST,  
ESPECIALLY FOR THE WEEKEND INTO EARLY NEXT WEEK. TIMING OF ARCTIC  
FRONTS WILL HAVE A BIG IMPACT ON DAILY TEMPERATURES...A DIFFERENCE  
OF JUST A FEW HOURS CAN MEAN THE DIFFERENCE BETWEEN 20S AND 40S  
FOR HIGHS.  
 

 
   
AVIATION
 
(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING)  
ISSUED AT 433 AM MST TUE JAN 22 2019  
 
LINGERING AREAS OF LIGHT SNOW WILL END ACROSS SOUTHERN SOUTH  
DAKOTA EARLY THIS MORNING. MVFR/IFR CONDITIONS WILL PERSIST ACROSS  
MUCH OF THE AREA THROUGH LATE MORNING, WITH IMPROVING CONDITIONS  
THIS AFTERNOON. NORTHWEST WINDS OF 15 TO 30 MPH, WITH HIGHER GUSTS  
THIS MORNING, WILL GRADUALLY DECREASE IN THE AFTERNOON.  
 

 
   
UNR WATCHES/WARNINGS/ADVISORIES
 
 
SD...NONE.  
WY...NONE.  

 
 

 
 
UPDATE...7  
DISCUSSION...7  
AVIATION...26  
 
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