788  
FXUS65 KCYS 271725  
AFDCYS  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE CHEYENNE WY  
1025 AM MST THU FEB 27 2020  
   
UPDATE
 
 
ISSUED AT 426 AM MST THU FEB 27 2020  
   
..PLEASE SEE LATEST 12Z AVIATION DISCUSSION
 
 
UPDATE ISSUED AT 349 AM MST THU FEB 27 2020  
 
WINDS HAVE STAYED BELOW WARNING LEVELS OVER THE SUMMIT AND OUT BY  
ARLINGTON SO FAR THIS MORNING. WENT AHEAD AND CANCELLED THE  
WARNING EARLY AS THE WINDS ARE ONLY EXPECTED TO DECREASE EVEN  
MORE. UPDATES HAVE BEEN SENT.  
 

 
   
SHORT TERM
 
(TODAY AND TONIGHT)  
ISSUED AT 130 AM MST THU FEB 27 2020  
 
FORECAST CHALLENGES WITH THIS MORNINGS FORECAST PACKAGE DEAL WITH  
STRONG WINDS CURRENTLY AND THEN TIMING ON A STRONG COLD FRONT  
SUNDAY INTO MONDAY.  
 
CURRENTLY...A 1032MB SURFACE HIGH PRESSURE BEING ANALYZED IN  
NORTHWESTERN COLORADO. CLIPPER SYSTEM TRACKING ACROSS OUR NORTHERN  
COUNTIES INTO THE NORTHERN NEBRASKA PANHANDLE WITH A 10MB SLPRES  
GRADIENT BETWEEN CRAIG AND CASPER. GFS CONTINUES TO SHOW 750 AND  
800MB WINDS NEAR 50KTS ACROSS THE SOUTH LARAMIE RANGE BETWEEN NOW  
AND 12Z THIS MORNING. THE EMKAY UPR SITE HAS SHOWN SIGNS OF  
DECREASING WINDS...BUT CYS VWP SHOWING WINDS HAVE SIGNIFICANTLY  
INCREASED OVER THE PAST HOUR RIGHT OFF THE SURFACE. UP TO 45KTS  
NOW RIGHT OFF THE SURFACE...SO WILL KEEP THE HIGH WIND WARNING  
GOING THIS MORNING TIL 12Z.  
 
SNOW SHOWERS ASSOCIATED WITH THE CLIPPER SYSTEM EXPECTED MAINLY  
ACROSS THE NORTHERN NEBRASKA PANHANDLE AND THE SNOWY/SIERRA MADRE  
RANGES THROUGH THE DAY TODAY. HIRES GUIDANCE SHOWS THE SHOWERS  
MAINLY THIS MORNING WITH SIGNIFICANTLY DECREASING COVERAGE AFTER  
18Z.  
   
LONG TERM
 
(FRIDAY THROUGH WEDNESDAY)  
ISSUED AT 130 AM MST THU FEB 27 2020  
 
WILL BE DEALING WITH CHANCES FOR STRONG WINDS THROUGH SATURDAY AS  
WE STAY IN STRONG NORTHWEST FLOW. COULD HAVE ANOTHER BRIEF HIGH  
WIND EVENT SATURDAY AS CRAIG TO CASPER 850/700MB HEIGHT GRADIENTS  
APPROACH 60MTRS. CERTAINLY LOOKS GOOD FOR BORDEAUX AS 750MB WINDS  
AROUND 55KTS SATURDAY AFTERNOON RIGHT OVER BORDEAUX.  
 
ATTENTION TURNS TO A STRONG COLD FRONT APPROACHES FROM THE  
NORTHWEST SUNDAY. FRONT LOOKS TO BE NEAR THE WYOMING/COLORADO  
STATE LINE BY 18Z SUNDAY. BOTH THE GFS AND ECMWF HAVE BEEN SHOWING  
THIS FEATURE THE PAST SEVERAL DAYS. ECMWF SHOWS A FASTER SOLUTION  
WITH PRECIP BECOMING WIDESPREAD LATE SUNDAY MORNING. GFS ROUGHLY  
6-12 HOURS SLOWER. GFS SHOWING OUR NORTHERN COUNTIES GETTING  
CLOSE TO .75 INCHES OF LIQUID WHILE THE ECMWF SHOWING AROUND .3  
INCHES. WITH 700MB TEMPERATURES -12 TO -14C....LOOKING AT 15 TO 1  
RATIOS...SO ANYWHERE FROM 4 TO 11 INCHES OF SNOW LOOKING LIKELY  
FOR CONVERSE/NIOBRARA COUNTIES AND THE NORTHERN NEBRASKA  
PANHANDLE.  
 
SNOW BAND SHIFTS SOUTH TO THE I-80 CORRIDOR FROM SIDNEY TO RAWLINS  
SUNDAY EVENING INTO MONDAY MORNING. GIVEN THE SLOWER ONSET FROM  
THE GFS...THIS AREA COULD STILL BE SNOWING THROUGH MONDAY  
AFTERNOON. LIKELY GOING TO NEED SOME WINTER HEADLINES. WILL WAIT  
ANOTHER DAY...BUT WANT TO GET THE WATCH OUT BY FRIDAY MORNING AT  
THE LATEST FOR THOSE FOLKS WHO MAY BE GOING OUT TO THE MOUNTAINS  
FOR THE WEEKEND.  
 
LOOKS LIKE ANOTHER SNOW EVENT TUESDAY NIGHT INTO WEDNESDAY AS  
ANOTHER SYSTEM MOVES THROUGH THE AREA. THIS ONE MAY HAVE STRONGER  
WINDS ASSOCIATED WITH IT AS GFS 700MB WINDS UP NEAR 40-45KTS WITH  
THE SNOW.  
 

 
   
AVIATION
 
(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)  
ISSUED AT 1022 AM MST THU FEB 27 2020  
 
WYOMING TAFS...VFR. WIND GUSTS TO 33 KNOTS UNTIL 02Z.  
 
NEBRASKA TAFS...MVFR AT ALLIANCE UNTIL 19Z, THEN VFR. WIND GUSTS  
TO 28 KNOTS UNTIL 01Z.  
 
VFR AT ALLIANCE UNTIL 20Z, THEN MVFR UNTIL 22Z, THEN VFR. WIND  
GUSTS TO 35 KNOTS UNTIL 22Z.  
 
VFR AT SCOTTSBLUFF AND SIDNEY. WIND GUSTS TO 38 KNOTS UNTIL 01Z.  
 

 
   
FIRE WEATHER
 
 
ISSUED AT 130 AM MST THU FEB 27 2020  
 
A CLIPPER SYSTEM WILL MOVE THROUGH THE NORTHERN PANHANDLE THIS  
MORNING THAT WILL BRING FAIRLY WIDESPREAD SNOW TO THE NORTHERN  
NEBRASKA PANHANDLE THIS MORNING BEFORE MOVING EAST INTO CENTRAL  
NEBRASKA. EXPECTING SOME MOUNTAIN SNOW SHOWERS TODAY FOR THE SNOWY  
AND SIERRA MADRE RANGES...MOST OTHER AREAS WILL REMAIN DRY TODAY  
WITH DECREASING WIND GUSTS. WE STAY IN A RATHER WINDY PATTERN AS  
HIGH PRESSURE REMAINS WEST OF OUR AREA AND WE STAY IN NORTHWEST  
WINDFLOW. DRY CONDITIONS EXPECTED FRIDAY AND SATURDAY ACROSS  
SOUTHEAST WYOMING AND NEBRASKA PANHANDLE. COULD GET NEAR CRITICAL  
AFTERNOON HUMIDITY SATURDAY AS TEMPERATURES CLIMB INTO THE 60S. A  
WIDESPREAD SNOW EVENT TAKING SHAPE SUNDAY AFTERNOON AS A COLD  
FRONT APPROACHES FROM THE NORTHWEST. MOST AREAS LIKELY TO RECEIVE  
AT LEAST 3 TO 4 INCHES OF SNOW WITH SOME AREAS RECEIVING  
CONSIDERABLY MORE BY MONDAY AFTERNOON.  
 

 
   
CYS WATCHES/WARNINGS/ADVISORIES
 
 
WY...NONE.  
NE...NONE.  

 
 

 
 
UPDATE...CW  
SHORT TERM...GCC  
LONG TERM...GCC  
AVIATION...RUBIN  
FIRE WEATHER...GCC  
 
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