185  
FXUS65 KCYS 210816  
AFDCYS  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE CHEYENNE WY  
216 AM MDT TUE OCT 21 2014  
   
SHORT TERM
 
(TODAY THROUGH THURSDAY)  
ISSUED AT 215 AM MDT TUE OCT 21 2014  
 
CURRENT IR SATELLITE LOOP SHOWS MAINLY CLEAR SKIES ACROSS  
SOUTHEAST WYOMING AND WESTERN NEBRASKA...ALTHOUGH CLOUDS ARE  
DEVELOPING AND PUSHING NORTHWARD OVER COLORADO. A VIGOROUS UPPER  
LEVEL SHORTWAVE TROUGH IS CURRENTLY PUSHING ACROSS THE NORTHERN  
GREAT BASIN REGION EARLY THIS MORNING WITH SOME LIGHT RAIN BEING  
REPORTED ACROSS NRN NEVADA AND IDAHO. SKIES WILL BECOME PARTLY  
CLOUDY THIS MORNING ALONG AND WEST OF THE LARAMIE RANGE AS THIS  
TROUGH WILL QUICKLY MOVE INTO WESTERN WYOMING BY THIS AFTERNOON.  
WINDS WILL INCREASE OUT OF THE SOUTH OR SOUTHWEST TODAY AHEAD OF  
THE COLD FRONT...WHICH WILL GRADUALLY PUSH ACROSS THE AREA  
SOMETIME LATER TODAY AND INTO TONIGHT. THERE IS NOT MUCH THAT IS  
REALLY IMPRESSIVE ABOUT THIS SYSTEM AS IT EJECTS NORTHEAST ACROSS  
WYOMING AND MONTANA THROUGH TONIGHT. ALL MODELS INDICATE A WEAKENING  
JET ALOFT...WHICH WILL RESULT IN WEAK UPPER LEVEL DYNAMICS. THIS  
WEAKENING APPEARS TO BE INFLUENCED BY THE STRENGTH OF THE HIGH  
AMPLITUDE RIDGE ACROSS THE CENTRAL UNITED STATES. THERE IS SOME  
MARGINAL INSTABILITY PRESENT AND SOME WEAK LARGE SCALE LIFT...SO  
INCREASED POP BETWEEN 25 TO 35 PERCENT ALONG THE I80 CORRIDOR  
THROUGH EARLY WEDNESDAY...MAINLY ACROSS SOUTHEAST WYOMING. CAN  
NOT RULE OUT A FEW THUNDER SHOWERS THIS AFTERNOON AND THIS EVENING  
AS WELL AS LI/S LOWER BETWEEN ZERO AND -2C. MOST OF THE ACTIVITY WILL  
PRIMARILY BE RAIN SHOWERS WITH SOME SNOW IN THE HIGHER MOUNTAINS.  
PRECIP WILL BE LIGHT WITH QPF VALUES BELOW 0.25...AND MOST  
LOCATIONS ONLY SEEING A TRACE UP TO A TENTH OF AN INCH OF LIQUID.  
TEMPERATURES WILL BE WARM TODAY WITH HIGHS IN THE MID TO UPPER 60S  
WEST OF THE LARAMIE RANGE...AND BETWEEN 70 TO 80 DEGREES ALONG AND  
EAST OF I25 INCLUDING WESTERN NEBRASKA.  
 
TEMPERATURES WILL BE 5 TO 10 DEGREES COOLER ON WEDNESDAY BEHIND  
THE FRONT...BUT WILL STILL BE SEASONABLE FOR THIS TIME OF THE YEAR  
AND GENERALLY IN THE UPPER 50S TO UPPER 60S. KEPT POP BELOW 15  
PERCENT ON WEDNESDAY...BUT WILL HAVE TO WATCH THE I80 CORRIDOR  
NEAR THE COLORADO BORDER FOR SOME ISOLATED SHOWERS AND PERHAPS A  
FEW LIGHTNING STRIKES DUE TO LLVL INSTABILITY AND SOME LINGERING  
MOISTURE. OTHERWISE...ANOTHER WARMING TREND IS EXPECTED TO BEGIN  
ON THURSDAY AS AN UPPER LEVEL RIDGE BEGINS TO EXTEND NORTHWARD  
ACROSS THE ROCKY MOUNTAINS.  
   
LONG TERM
 
(THURSDAY NIGHT THROUGH MONDAY)  
ISSUED AT 215 AM MDT TUE OCT 21 2014  
 
CONTINUED DRY AND BREEZY/WINDY CONDITIONS FOR MOST OF THE LONG  
TERM. BUT THERE ARE CHANGES COMING UP.  
 
UPPER RIDGE AXIS LOOKS TO PASS OVERHEAD THURSDAY NIGHT. GFS  
SHOWING 700MB WINDS INCREASING TO NEAR 40KTS BY FRIDAY MORNING AS  
THE RIDGE AXIS CONTINUES TO MOVE OFF TO THE EAST. GOING TO BE  
PRETTY WARM WITH THESE STRONGER...DOWNSLOPING WINDS FOR FRIDAY AND  
SATURDAY. HAVE HIGHS BOTH DAYS APPROACHING 80 IN THE PANHANDLE.  
GFS 700MB TEMPERATURES ARE +8 TO +10C OVER THE CWFA FRIDAY AND  
SATURDAY AHEAD OF OUR NEXT COLD FRONT.  
 
GFS AND ECMWF BOTH CONTINUE TO SHOW A CHANGE FOR SUNDAY NIGHT INTO  
MONDAY. ECMWF STRONGER ON THE SHORTWAVE OVER THE GFS AND HAS THE  
SHORTWAVE TRACKING A LITTLE FURTHER SOUTH. DID BUMP UP POPS FOR  
THIS TIMEFRAME. WITH 700MB TEMPERATURES OF -4 TO -6C...A LOT OF  
THIS PRECIP COULD FALL AS SNOW. SHOULD THE ECMWF SOLUTION HOLD  
TRUE...WE COULD BE LOOKING AT WINTER HEADLINES AS TOTAL QPF  
FORECAST CLOSE TO .75 INCHES.  
 

 
   
AVIATION
 
(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)  
ISSUED AT 1111 PM MDT MON OCT 20 2014  
 
COLD FRONT SET TO MOVE INTO THE AREA TUESDAY AFTERNOON WILL BRING  
SOME SMALL CHANCES FOR SHOWERS AND THUNDERSTORMS...MAINLY FOR KLAR  
AND KRWL. BEST CHANCES WILL BE OVER COLORADO THOUGH AND OUR  
PANHANDLE AIRPORTS AS WELL AS KCYS SHOULD REMAIN DRY. VFR WITH  
GUSTY WEST WINDS AHEAD OF THE FRONT.  
 

 
   
FIRE WEATHER
 
 
ISSUED AT 150 AM MDT TUE OCT 21 2014  
 
MINIMAL FIRE WEATHER CONCERNS THIS WEEK WITH DAYTIME HUMIDITIES  
MAINLY BETWEEN 20 TO 35 PERCENT. BREEZY OR WINDY CONDITIONS ARE  
EXPECTED THIS AFTERNOON AS WELL AS WEDNESDAY AS A WEAK COLD FRONT  
PUSHES ACROSS WYOMING. THERE IS A CHANCE OF RAIN SHOWERS AND  
PERHAPS A FEW THUNDERSTORMS ALONG INTERSTATE 80 THIS AFTERNOON AND  
INTO TONIGHT. OTHERWISE...DRY CONDITIONS ARE EXPECTED AFTER  
WEDNESDAY AND INTO NEXT WEEKEND.  
 

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

 
 

 
 
SHORT TERM...TJT  
LONG TERM...CLAYCOMB  
AVIATION...CLAYCOMB  
FIRE WEATHER...TJT  
 
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