936  
FXUS65 KCYS 170023  
AFDCYS  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE CHEYENNE WY  
623 PM MDT MON OCT 16 2017  
   
UPDATE
 
 
ISSUED AT 622 PM MDT MON OCT 16 2017  
 
AS CRITICAL FIRE CONDITIONS CONTINUE TO DIMINISH THIS EVENING,  
HAVE ALLOWED THE RED FLAG WARNING TO EXPIRE AT 6 PM. ANOTHER  
CRITICAL FIRE WEATHER DAY WILL AGAIN BE POSSIBLE ON TUESDAY.  
 

 
   
SHORT TERM
 
(THIS EVENING THROUGH TUESDAY)  
ISSUED AT 200 PM MDT MON OCT 16 2017  
 
WARM AND VERY DRY WEATHER PATTERN TO PERSIST THROUGH TUESDAY. WEAK  
RIDGING REMAINS IN PLACE OVER THE INTERMOUNTAIN WEST AND SE  
WYOMING/W NEBRASKA WILL LIE ON THE SOUTHERN FRINGE OF MODERATELY  
FAST ZONAL FLOW ALOFT. A SUBTLE SHORTWAVE WILL SKIRT ACROSS THE  
AREA FROM THE WEST DURING THE DAY TUESDAY WHICH MAY ENHANCE THE  
FLOW ALOFT AS WELL AS PUSH THE SURFACE TROUGH A BIT FURTHER EAST  
THAN TODAY. FORECAST SOUNDINGS CONTINUE TO SHOW VERY DRY AND WELL  
MIXED CONDITIONS DEVELOPING ACROSS THE ENTIRE AREA TUESDAY  
AFTERNOON WITH 700 MB TEMPS WARMING TO AROUND 8C. SHOULD SEE HIGH  
TEMPS TOP OUT IN THE 70S TO NEAR 80 EAST OF THE LARAMIE RANGE  
ESPECIALLY WITH THE STRONGER WEST TO NORTHWEST WINDS AND  
DOWNSLOPING ADDING TO THE WARMING. LOOKS LIKE ANOTHER CRITICAL  
FIRE WEATHER DAY TUESDAY FOR A LARGE PART OF THE AREA AS MENTIONED  
BELOW.  
   
LONG TERM
 
(TUESDAY NIGHT THROUGH MONDAY)  
ISSUED AT 200 PM MDT MON OCT 16 2017  
 
WARM AND BREEZY CONDITIONS CONTINUE WEDNESDAY WITH ANOTHER POSSIBLE  
RED FLAG DAY. AFTERNOON HUMIDITIES ACROSS THE LARAMIE RANGE AND  
ADJACENT FOOTHILLS DOWN BELOW 15 PERCENT, ONLY QUESTION WILL BE  
WINDS. GFS SOUNDINGS PRETTY CLOSE WITH 25-30KTS RIGHT OFF THE  
SURFACE, SO ANOTHER CRITICAL FIRE WEATHER DAY LIKELY WEDNESDAY.  
 
IN FACT, WE COULD BE DEALING WITH FIRE WEATHER CONDITIONS WELL INTO  
THE WEEK AS WARM/DRY WEATHER LOOKS TO CONTINUE AT LEAST THROUGH  
FRIDAY. FORECAST HUMIDITY IN THE LOW TO MID TEENS BOTH DAYS.  
 
NEXT CHANCE FOR PRECIP WILL BE SATURDAY ACROSS OUR WESTERN ZONES AND  
WE COULD BE IN FOR A FAIRLY STRONG WIND EVENT SATURDAY NIGHT INTO  
SUNDAY AS WELL. GFS 700MB WINDS WELL ABOVE 50KTS SATURDAY EVENING  
INTO SUNDAY. GFS 700MB CRAIG TO CASPER GRADIENT INCREASES TO  
60MTRS AFTER 06Z SUNDAY AND CONTINUES THROUGH THE DAY. IF THIS  
FORECAST HOLDS TRUE, WE WILL BE LOOKING AT WARNING LEVEL WINDS IN  
THE WIND PRONE AREAS (ARLINGTON, BORDEAUX, SOUTH LARAMIE RANGE).  
 

 
   
AVIATION
 
(FOR THE 00Z TAFS THROUGH 00Z TUESDAY EVENING)  
ISSUED AT 622 PM MDT MON OCT 16 2017  
 
VFR CONDITIONS WILL PREVAIL THROUGH THE PERIOD, WITH JUST SOME  
HIGH CLOUDS STREAMING THROUGH FROM TIME TO TIME. WINDS WILL  
CONTINUE TO DIMINISH THIS EVENING, WITH ANOTHER ROUND OF  
WEST/SOUTHWEST WINDS FOR SOUTHEAST WYOMING TERMINALS AFTER 16Z  
TUESDAY.  
 

 
   
FIRE WEATHER
 
 
ISSUED AT 622 PM MDT MON OCT 16 2017  
 
CRITICAL FIRE CONDITIONS CONTINUE TO DIMINISH THIS EVENING,  
THEREFORE THE RED FLAG WARNING HAS BEEN ALLOWED TO EXPIRE ON TIME  
AT 6P. LITTLE CHANGE IN AIR MASS IS EXPECTED FOR TUESDAY AND  
POSSIBLY EVEN INTO WEDNESDAY, SO WILL CONTINUE THE FIRE WEATHER  
WATCH LOOKS GOOD ON TUESDAY. WILL EVALUATE THE LATEST INFORMATION  
THIS EVENING, BEFORE POSSIBLY UPGRADING WITH A LATER EVENING  
UPDATE.  
 

 
   
CYS WATCHES/WARNINGS/ADVISORIES
 
 
WY...FIRE WEATHER WATCH TUESDAY AFTERNOON FOR WYZ301-306-309-310.  
 
NE...FIRE WEATHER WATCH TUESDAY AFTERNOON FOR NEZ312-313.  
 

 
 

 
 
UPDATE...CAH  
SHORT TERM...DEL  
LONG TERM...GCC  
AVIATION...CAH  
FIRE WEATHER...CAH  
 
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