293  
FXUS65 KCYS 262346  
AFDCYS  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE CHEYENNE WY  
446 PM MST SUN FEB 26 2017  
   
UPDATE
 
 
ISSUED AT 253 PM MST SUN FEB 26 2017  
 
WENT AHEAD AND CANCELLED THE BLOWING SNOW ADVISORY EARLY. LOOKING  
AT WYDOT WEBCAMS, SNOW LOOKS TO BE SETTLED PRETTY GOOD AS IT HAS  
BEEN BLOWING AROUND PRETTY GOOD EARLIER THIS MORNING. STILL  
GETTING FAIRLY STRONG WINDS, BUT SNOW SEEMS TO HAVE POSSIBLY  
CRUSTED OR HAS FOUND ITS PERMANENT DRIFTED AREA. WILL HANDLE THE  
WINDS WITH AN SPS.  
 

 
   
SHORT TERM
 
(THIS EVENING THROUGH TUESDAY NIGHT)  
ISSUED AT 300 PM MST SUN FEB 26 2017  
 
ACTIVE WEATHER IN THE SHORT TERM WITH WINTER HEADLINES AND WINDS  
THE MAIN FORECAST CONCERNS.  
 
CURRENTLY...STRONG WINDS CONTINUE THIS AFTERNOON IN THE WIND PRONE  
AREAS OF SOUTHEAST WYOMING. DID HAVE A FEW GUSTS AROUND 58MPH THIS  
MORNING OUT BY ARLINGTON WITH LOW 50S OVER THE SUMMIT AND MID 40S  
UP BY ARLINGTON. LOOKING AT AREA WEBCAMS, ITS LOOKING LIKE THE  
BLOWING SNOW MAY HAVE SETTLED DOWN FROM THIS MORNING AND MAY BE  
ABLE TO END THE BLOWING SNOW ADVISORY EARLIER THAN EXPECTED. WILL  
CONTINUE TO MONITOR FOR ANOTHER HOUR OR SO AND THEN DECIDE.  
 
NEXT PACIFIC STORM SYSTEM MOVING INTO THE PACNW THIS AFTERNOON.  
COLD FRONT OVER SOUTHERN MONTANA LIKELY AT LEAST PARTIALLY  
RESPONSIBLE FOR THE STRONG WINDS TODAY. A 1020 SURFACE HIGH  
SITUATED OVER SOUTHWESTERN WYOMING THIS AFTERNOON AIDING IN MOSTLY  
SUNNY SKIES OVER THE AREA.  
 
THIS NEXT STORM SYSTEM BEGINS TO IMPACT THE AREA MONDAY. ALL  
MODELS IN GOOD AGREEMENT WITH THE FRONT MOVING INTO CARBON COUNTY  
MONDAY AFTERNOON. NAM, SREF, EC, GFS ALL AGREE ON TIMING AND  
LOCATION OF A MODERATE QPF AREA MOVING INTO CARBON COUNTY TOMORROW  
AFTERNOON. NAM THE MOST BULLISH WITH OVER .5 INCHES QPF, BUT OTHER  
MODELS NOT TOO FAR BEHIND. LOOKS LIKE MOST OF CARBON COUNTY WILL  
BE UNDER THIS PRECIP FOR A 12-15 HOUR TIME SPAN BEFORE THE FRONT  
MOVES INTO COLORADO. AT THE SAME TIME, GFS 700MB WINDS AHEAD OF  
THE FRONT UP NEAR 40KTS FROM THE SOUTHWEST THAT SHIFT NORTHWEST AT  
35KTS BEHIND THE FRONT.  
 
DID DISAGREE WITH THE WPC SNOW AMOUNTS THEY ARE FORECASTING AND  
DID COORDINATE WITH THEM ON MY CONCERNS. ALL THIS PRECIP SHOULD  
FALL AS SNOW AS WE ARE ONLY FORECASTING HIGHS OUT AT RAWLINS OF  
28 TOMORROW. SO I AM GETTING SNOW AMOUNTS OF 3+ INCHES FROM  
RAWLINS SOUTH TO SARATOGA WITH HIGHEST AMOUNTS OUTSIDE THE  
MOUNTAINS IN THE FOOTHILLS. SIERRA MADRE RANGE STANDS BEST CHANCE  
AT SEEING 12+ INCHES WHILE THE SNOWY RANGE MAY GET SHADOWED BY THE  
SIERRA MADRE. THIS LEADS TO MY HEADLINES.  
 
WENT WITH A WINTER STORM WARNING FOR THE SIERRA MADRE RANGE AND AN  
ADVISORY FOR THE SNOWY RANGE. WINDY CONDITIONS OUT BY RAWLINS AND  
ALONG I-80 NEAR ARLINGTON COULD PRODUCE SIGNIFICANT IMPACTS. SO  
ISSUED A WINTER STORM WATCH FOR THE AREAS SURROUNDING THE  
MOUNTAINS FOR MONDAY AFTERNOON THROUGH TUESDAY MORNING. THERE ARE  
IMPACTS AT ARLINGTON WITH NO SNOW FALLING, SO YOU ADD 3-5 INCHES  
WITH 40 MPH WINDS SIMILAR TO THE PAST COUPLE DAYS, THERE CERTAINLY  
LOOKS TO BE MAJOR IMPACTS OUT THERE.  
   
LONG TERM
 
(WEDNESDAY THROUGH SUNDAY)  
ISSUED AT 300 PM MST SUN FEB 26 2017  
 
WEDNESDAY...ASIDE FROM A FEW MOUNTAIN SNOW SHOWERS, THE FIRST DAY OF  
MARCH LOOKS TO START OUT DRY. TEMPERATURES WILL BE COOLER THAN  
NORMAL CONSIDERING THE SNOWPACK AND PROGGED 700 MB TEMPERATURES NEAR  
-10 CELSIUS. WINDY DAY, WITH NEAR HIGH WIND CRITERIA WINDS LIKELY AT  
OUR WIND PRONE LOCATIONS SUCH AS ARLINGTON, BORDEAUX AND VEDAUWOO  
OVER THE I-80 SUMMIT BETWEEN LARAMIE AND CHEYENNE.  
 
THURSDAY...ALTHOUGH FLOW ALOFT REMAINS FROM THE NORTHWEST, HEIGHTS  
ALOFT RISE HELPING THE TEMPERATURES TO RISE A FEW DEGREES AT MOST  
LOCATIONS. CONTINUED WINDY BASED ON PROGGED LOW AND MID LEVEL  
GRADIENTS, THOUGH LIKELY NOT AS WINDY AS WEDNESDAY AS MID LEVEL  
WINDS DECREASE SLIGHTLY. LACK OF LOW AND MID LEVEL MOISTURE SUGGESTS  
A DRY DAY.  
 
FRIDAY...AS HAPPENS QUITE OFTEN, WITH THE FLOW ALOFT BACKING TO  
WESTERLY, SURFACE LEE TROUGHING BECOMES BETTER ESTABLISHED AND THE  
ATMOSPHERE WILL WARM SUBSTANTIALLY AS A RESULT WITH HIGH  
TEMPERATURES WARMING TO ABOVE NORMAL READINGS.  
 
SATURDAY...WARMING TREND CONTINUES IN EARNEST UNDER ZONAL FLOW AND A  
MODERATING AIRMASS SENDING HIGH TEMPERATURES ABOVE NORMAL FOR EARLY  
MARCH. CONTINUED DRY WITH ABSENCE OF SIGNIFICANT LOW AND MID  
LEVEL MOISTURE. ANOTHER QUITE WINDY DAY PER PROGGED LOW AND MID  
LEVEL GRADIENTS.  
 
SUNDAY...SOMEWHAT COOLER TEMPERATURES AS A PROGRESSIVE AND LOW  
AMPLITUDE SHORTWAVE TROUGH ALOFT AND COLD FRONT PROGRESS WEST TO  
EAST ACROSS OUR FORECAST AREA. IF SHORTWAVE TIMING IS CORRECT, WE  
MAY SEE ENOUGH LOW AND MID LEVEL MOISTURE TO PRODUCE A CHANCE OF  
RAIN OR SNOW ALONG AND WEST OF A DOUGLAS TO RAWLINS LINE.  
 

 
   
AVIATION
 
(FOR THE 00Z TAFS THROUGH 00Z MONDAY EVENING)  
ISSUED AT 421 PM MST SUN FEB 26 2017  
 
WYOMING TAFS...VFR PREVAILS, EXCEPT FOR MVFR AT RAWLINS FROM 12Z  
TO 18Z. WIND GUSTING TO 25 KNOTS AT RAWLINS THROUGH 06Z. WIND  
GUSTING FROM 22 TO 30 KNOTS AT ALL SITES AFTER 12Z MONDAY.  
 
NEBRASKA TAFS...VFR. WIND GUSTING TO 23 KNOTS AFTER 15Z MONDAY AT  
ALLIANCE.  
 

 
   
FIRE WEATHER
 
 
ISSUED AT 300 PM MST SUN FEB 26 2017  
 
EXTENSIVE SNOW PACK, COLD TEMPERATURES, HIGH DAYTIME HUMIDITIES,  
AND NON-CRITICAL FUELS WILL PRECLUDE FIRE WEATHER CONCERNS THROUGH  
MID-WEEK. STRONG AND GUSTY WEST WINDS ACROSS THE WIND PRONE AREAS  
OF SOUTHEAST WYOMING WILL CONTINUE TO PRODUCE BLOWING AND DRIFTING  
SNOW THROUGH LATE THIS AFTERNOON. THERE WILL BE WINDY PERIODS MUCH  
OF THIS WEEK, ESPECIALLY FOR THE NORMAL WIND PRONE AREAS. THERE  
WILL BE CHANCES FOR SNOW EARLY THIS WEEK, MAINLY ALONG AND WEST OF  
THE LARAMIE RANGE.  
 

 
   
CYS WATCHES/WARNINGS/ADVISORIES
 
 
WY...WINTER WEATHER ADVISORY FROM 2 PM MONDAY TO 5 AM MST TUESDAY FOR  
WYZ114.  
 
WINTER STORM WATCH FROM MONDAY AFTERNOON THROUGH LATE MONDAY  
NIGHT FOR WYZ109>111-113.  
 
WINTER STORM WARNING FROM 2 PM MONDAY TO 5 AM MST TUESDAY FOR  
WYZ112.  
 
NE...NONE.  

 
 

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