470  
FXUS65 KCYS 142350  
AFDCYS  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE CHEYENNE WY  
550 PM MDT WED APR 14 2021  
   
SHORT TERM
 
(THIS EVENING - FRIDAY NIGHT)  
ISSUED AT 300 PM MDT WED APR 14 2021  
 
STATIONARY UPPER LOW CONTINUES TO SPIN OVER THE GREAT BASIN THIS  
AFTERNOON. DRIER AIR ALOFT HAS BEEN ROTATING NORTHEASTWARD INTO  
CO, WITH SOME RAIN/SNOW SHOWERS DEVELOPING OVER NORTHWEST CO. SKIES  
WERE MOSTLY CLOUDY, WHICH HAS KEPT TEMPERATURES IN THE 20S AND 30S.  
WINDS WERE VARIABLE 5-15 KT.  
 
THE UPPER LOW TO THE WEST WILL SLOWLY TRACK TO THE EAST ACROSS UT,  
WY AND CO DURING THE NEXT 24 TO 48 HOURS, WITH THE SURFACE LOW  
MOVING ACROSS CO. THE COMBINATION OF EAST TO SOUTHEAST UPSLOPE  
FLOW, ABUNDANT MOISTURE AND ENERGY ALOFT WILL PRODUCE OCCASIONAL  
SNOW SHOWERS THROUGH FRIDAY. MODEST LOW/MID LEVEL LAPSE RATES AND  
SBCAPE UP TO 200 J/KG MAY PRODUCE A FEW THUNDERSTORMS OVER  
SOUTHEAST CARBON AND SOUTHWEST ALBANY COUNTIES THURSDAY AFTERNOON.  
 
SNOWFALL RATES OF 1-2"/HR WILL BE POSSIBLE THURSDAY AFTERNOON AND  
EARLY EVENING OVER THE SNOWY AND SOUTH LARAMIE RANGES. OUTSIDE  
THESE ZONES, WIDESPREAD LIGHT TO MODERATE SNOW ACCUMULATIONS ARE  
FORECAST. WINTER STORM WARNINGS REMAIN IN EFFECT FOR THE SNOWY  
AND SOUTH LARAMIE RANGES, AS WELL AS THE NORTH SNOWY RANGE FOR  
THE COMBINATION OF MODERATE TO HEAVY SNOW AND BLOWING SNOW WITH  
WINDS GUSTING AS HIGH AS 40 MPH. ELSEWHERE, WINTER WEATHER ADVISORIES  
ARE IN EFFECT AND EXPANDED TO INCLUDE THE REMAINDER OF THE WESTERN  
NE PANHANDLE THROUGH EARLY FRIDAY MORNING. FOUR TO EIGHT INCHES  
ARE EXPECTED EAST OF THE LARAMIE RANGE, 6 TO 12 INCHES FOR  
ARLINGTON/ELK MOUNTAIN AND SOUTH LARAMIE RANGE, 3 TO 8 INCHES FOR  
MUCH OF CARBON COUNTY, AND 12 TO 18 INCHES FOR THE SNOWY RANGE.  
SNOW WILL TAPER OFF LATER FRIDAY MORNING INTO THE AFTERNOON.  
 
TEMPERATURES WILL CONTINUE BELOW SEASONAL NORMALS WITH HIGHS IN THE  
30S AND LOWS IN THE 20S TO AROUND 30.  
   
LONG TERM
 
(SATURDAY - TUESDAY)  
ISSUED AT 346 AM MDT WED APR 14 2021  
 
A COOL & UNSETTLED PATTERN WILL LIKELY PERSIST THROUGH THE WEEKEND  
INTO EARLY NEXT WEEK W/ LARGE SCALE CYCLONIC FLOW ALOFT CONTINUING  
OVER MUCH OF CENTRAL AND EASTERN CONUS. AS SUCH, THE GFS AND ECMWF  
BOTH SHOW MULTIPLE DISTURBANCES DIVING SOUTH ACROSS THE NORTHERN &  
CENTRAL PLAINS THROUGH THE PERIOD. TEMPERATURES SHOULD REMAIN WELL  
BELOW NORMAL FOR QUITE SOME TIME W/ ALMOST DAILY CHANCES FOR RAIN/  
SNOW SHOWERS ACROSS THE AREA. ADDITIONAL SNOW ACCUMULATIONS SHOULD  
BE FAIRLY LIGHT.  
 

 
   
AVIATION
 
(FOR THE 00Z TAFS THROUGH 00Z THURSDAY EVENING)  
ISSUED AT 534 PM MDT WED APR 14 2021  
 
VFR CONDITIONS CURRENTLY ACROSS NE PANHANDLE TERMINALS WITH BKN TO  
OVC CEILINGS AROUND 3-6 KFT. MVFR TO IFR CONDITIONS ARE EXPECTED  
TO MOVE IN OVERNIGHT MAINLY AFTER 06Z INTO THURSDAY MORNING AS THE  
SYSTEM BRINGING SNOWFALL TO THE AREA APPROACHES. SNOW SHOWERS WITH  
REDUCTIONS IN VISIBILITY WILL BE POSSIBLE FOR NE PANHANDLE  
TERMINALS EARLY THURSDAY MORNING, BUT WILL BECOME MORE WIDESPREAD  
IN THE AFTERNOON AND EVENING ALONG WITH IFR CONDITIONS.  
 
SNOW SHOWERS HAVE ALREADY MOVED OVER SE WY TERMINALS EARLY THIS  
EVENING WITH IFR AND EVEN LIFR CONDITIONS. LOW CEILINGS ARE  
EXPECTED TO CONTINUE THROUGH THE NIGHT WHILE VISIBILITY LOWERS  
WITH PASSING SNOW SHOWERS. SNOWFALL WILL BECOME MORE WIDESPREAD  
AND PERSISTENT EARLY THURSDAY AFTERNOON CONTINUING THROUGH  
THURSDAY NIGHT FOR KCYS AND KLAR. SNOW SHOWERS AND VISIBILITY  
REDUCTIONS ARE POSSIBLE FOR KRWL THURSDAY AFTERNOON, BUT THE BULK  
OF THE PRECIPITATION WILL EVENTUALLY MOVE OFF TOWARDS THE EAST  
WITH MVFR CONDITIONS REMAINING THURSDAY NIGHT.  
 

 
   
FIRE WEATHER
 
 
ISSUED AT 220 PM MDT WED APR 14 2021  
 
NO FIRE WEATHER CONCERNS EXPECTED DUE TO WIDESPREAD SNOWFALL, COLD  
TEMPERATURES AND HIGH HUMIDITIES.  
 

 
   
CYS WATCHES/WARNINGS/ADVISORIES
 
 
WY...WINTER WEATHER ADVISORY FROM MIDNIGHT TONIGHT TO 6 AM MDT FRIDAY  
FOR WYZ101-102.  
 
WINTER WEATHER ADVISORY UNTIL 6 AM MDT FRIDAY FOR WYZ103>109-112-  
115-117>119.  
 
WINTER STORM WARNING UNTIL 6 PM MDT FRIDAY FOR WYZ114-116.  
 
WINTER WEATHER ADVISORY UNTIL 6 AM MDT FRIDAY FOR WYZ113.  
 
WINTER STORM WARNING UNTIL 6 AM MDT FRIDAY FOR WYZ110.  
 
NE...WINTER WEATHER ADVISORY FROM MIDNIGHT TONIGHT TO 6 AM MDT FRIDAY  
FOR NEZ095.  
 
WINTER WEATHER ADVISORY FROM 6 AM THURSDAY TO 9 AM MDT FRIDAY  
FOR NEZ002-003-019>021-054-055-096.  
 

 
 

 
 
SHORT TERM...MAJ  
LONG TERM...CLH  
AVIATION...MB  
FIRE WEATHER...MAJ  
 
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