447  
FXUS65 KCYS 250500  
AFDCYS  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE CHEYENNE WY  
1100 PM MDT SAT SEP 24 2016  
   
UPDATE
 
 
ISSUED AT 1053 PM MDT SAT SEP 24 2016  
WE ARE ISSUING A QUICK UPDATE TO REMOVE PRECIPITATION CHANCES  
DURING THE REMAINDER OF THE MORNING EXCEPT FOR THE NORTHEAST  
CORNER OF OUR FORECAST AREA WHERE THEY ARE STILL RECEIVING SOME  
LIGHT SHOWERS/SPRINKLES. OTHERWISE, THE CLOUDS WILL CONTINUE TO  
CLEAR OUT THE REMAINDER OF THE NIGHT WITH CHILLY TEMPERATURES  
EXPECTED.  
 

 
   
SHORT TERM
 
(TONIGHT - TUESDAY)  
 
A VIGOROUS UPPER-LEVEL LOW PRESSURE SYSTEM CONTINUES TO LIFT ACROSS  
THE NORTHERN PLAINS LATE THIS AFTERNOON, WITH A NARROW PLUME OF MID  
AND HIGH LEVEL MOISTURE EXTENDING ACROSS EASTERN WY WRAPPING AROUND  
THE BACK SIDE OF THE SYSTEM. WE STILL HAVE PLENTY OF H25 JET ENERGY  
OVER THE AREA TODAY WITH MUCH OF THE CWA IN THE LEFT EXIT REGION OF  
A 120-KNOT JET THROUGH AT LEAST 06Z. THIS SHOULD CONTINUE TO RESULT  
IN SCATTERED TO NUMEROUS SHOWERS THROUGH THIS EVENING. TEMPERATURES  
MAY BECOME COLD ENOUGH FOR SNOW ALONG/WEST OF THE LARAMIE RANGE BUT  
DYNAMICS AND MOISTURE AVAILABILITY SHOULD NOT SUPPORT ACCUMULATIONS  
LIKE WE SAW LAST NIGHT. BEYOND 12Z SUNDAY, CONSIDERABLE DRYING WILL  
OCCUR BENEATH A BUILDING UPPER-LEVEL RIDGE W/ NO CHANCES FOR PRECIP  
THROUGH THE REMAINDER OF THE PERIOD. A WARMING TREND IS EXPECTED AS  
H7 TEMPERATURES SLOWLY CLIMB BACK TO AROUND +10C BY MON/TUE.  
   
LONG TERM
 
(TUESDAY NIGHT NIGHT THROUGH SATURDAY)  
ISSUED AT 230 PM MDT SAT SEP 24 2016  
 
A QUIET WEATHER PATTERN IS EXPECTED NEXT WEEK WITH MAINLY DRY  
CONDITIONS THROUGH THE END OF THE WEEK. ALL MODELS SHOW THE UPPER  
LEVEL RIDGE AXIS REMAINING OVER GREAT PLAINS THROUGH THURSDAY  
BEFORE SOME SHORTWAVE ENERGY BEGINS TO LIFT NORTHEAST ACROSS THE  
ROCKY MOUNTAINS BY FRIDAY. HIGH TEMPERATURES WILL GENERALLY BE IN  
THE 70'S TO LOW 80'S ACROSS MOST OF THE FORECAST AREA...WITH THE  
WARMEST TEMPERATURES ACROSS THE LOWER ELEVATIONS OF WESTERN  
NEBRASKA AND FAR EASTERN WYOMING. HIGHS MAY REMAIN IN THE UPPER  
60'S WEST OF INTERSTATE 25 LATER IN THE WEEK AS SOME MID TO HIGH  
CLOUDS ENTER THE REGION. FOR LATE FRIDAY AND SATURDAY...THERE IS A  
CHANCE OF SOME SHOWER ACTIVITY AND ISOLATED THUNDER ACROSS THE  
MOUNTAINS AND EASTERN PLAINS AS TWO SHORTWAVE DISTURBANCES MOVE  
OUT OF THE GREAT BASIN REGION. KEPT POP AROUND 20 PERCENT IN THOSE  
LOCATIONS WITH SLIGHTLY COOLER TEMPERATURES. FURTHER OUT...MODELS  
INDICATE A RATHER STRONG STORM SYSTEM MOVING ACROSS THE PACIFIC NW  
FOR THE WEEKEND WITH 700MB TEMPERATURES RANGING FROM -5C TO -10C  
BEHIND THE COLD FRONT. THIS WILL LIKELY BE THE NEXT SYSTEM TO  
MONITOR AS WINDS AND WINTER WEATHER IMPACTS ARE POSSIBLE.  
 

 
   
AVIATION
 
(FOR THE 00Z TAFS THROUGH 00Z SUNDAY EVENING)  
ISSUED AT 537 PM MDT SAT SEP 24 2016  
 
BRIEF MVFR CIGS ACCOMPANYING SCT -SHRA THIS EVENING WEST OF THE  
LARAMIE RANGE INCLUDING LAR AND RWL. OTHERWISE, VFR CIGS WILL  
PREVAIL WITH GUSTY NORTHWEST WINDS OF 25-30 KT. PARTIAL CLEARING  
IS EXPECTED OVERNIGHT, WITH MOSTLY CLEAR SKIES SUNDAY. WINDS WILL  
DECREASE SLIGHTLY OVERNIGHT, BUT INCREASE ONCE AGAIN AFTER 15Z  
WITH GUSTS OF 25-30 KT.  
 

 
   
FIRE WEATHER
 
 
ISSUED AT 158 PM MDT SAT SEP 24 2016  
 
NO FIRE WEATHER CONCERNS OVER THE NEXT FEW DAYS W/ COOLER AFTERNOON  
TEMPERATURES AND RESULTANT HIGHER MINIMUM RH VALUES. WINDS OVER THE  
NEXT 12 TO 24 HOURS WILL BE BREEZY AT TIMES, BUT OVERALL CONDITIONS  
WILL BE OUTSIDE OF CRITICAL THRESHOLDS.  
 

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

 
 

 
 
UPDATE...REC  
SHORT TERM...CLH  
LONG TERM...TJT  
AVIATION...MJ  
FIRE WEATHER...CLH  
 
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