656  
FXUS65 KCYS 121122  
AFDCYS  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE CHEYENNE WY  
422 AM MST TUE DEC 12 2017  
   
SHORT TERM
 
(TODAY THROUGH THURSDAY)  
ISSUED AT 300 AM MST TUE DEC 12 2017  
 
NOT MUCH CHANGE FROM WHAT WE HAVE BEEN SEEING ACROSS SOUTHEAST  
WYOMING AND NEBRASKA PANHANDLE IN THE SHORT TERM.  
 
CURRENTLY...CLIPPER SYSTEM THAT BROUGHT THE STRONGER WINDS TO THE  
NEBRASKA PANHANDLE WELL EAST THIS MORNING ALLOWING FOR A DECREASED  
PRESSURE GRADIENT OVER THE AREA. WINDS GENERALLY PRETTY LIGHT  
ACROSS THE AREA THIS MORNING, GENERALLY UNDER 10 MPH. IR SATELLITE  
IMAGERY SHOWING CLEAR SKIES OVER MUCH OF THE WESTERN U.S. THIS  
MORNING AS UPPER HIGH PRESSURE REMAINS FIRMLY IN CONTROL OF THE  
WEATHER ACROSS THE ROCKIES.  
 
CLIPPER SYSTEM FOR WEDNESDAY WILL MOVE ACROSS SOUTH DAKOTA AND  
EASTERN NEBRASKA WHICH WILL INCREASE WINDS OVER AREAS EAST OF THE  
LARAMIE RANGE BEGINNING TONIGHT AND MUCH OF WEDNESDAY. GFS 850MB  
WINDS OVER THE PANHANDLE INCREASE TO 30-35KTS THIS EVENING AND UP  
TO 40-45KTS DURING THE DAY WEDNESDAY. WILL LIKELY EXPERIENCE  
STRONG WIND SIMILAR TO YESTERDAY FOR THE PANHANDLE WEDNESDAY WITH  
WIND GUSTS OF 40-45MPH. YET ANOTHER CLIPPER SYSTEM FOR THURSDAY  
WITH ANOTHER WINDY DAYS FOR AREAS EAST OF THE LARAMIE RANGE.  
   
LONG TERM
 
(THURSDAY NIGHT THROUGH MONDAY)  
ISSUED AT 300 AM MST TUE DEC 12 2017  
 
THURSDAY NIGHT/FRIDAY...MOSTLY CLEAR THURSDAY NIGHT WITH  
TEMPERATURES ABOVE NORMAL DUE TO DECENT MIXING AND SURFACE WINDS.  
FLOW ALOFT BACKS ON FRIDAY TO NORTHWEST WITH A SURFACE LEE TROUGH  
FORMING, HELPING TO BOOST MAXIMUM TEMPERATURES INTO THE 40S WEST OF  
I-25, AND 50S EAST OF I-25.  
 
SATURDAY...COOLER AND WETTER AS A SHORTWAVE TROUGH ALOFT AND ITS  
ASSOCIATED COLD FRONT SWEEP EASTWARD ACROSS OUR COUNTIES. CHANCES  
FOR SNOW SHOWERS, AND SOME RAIN SHOWERS, WILL INCREASE AFTER  
MIDNIGHT FRIDAY NIGHT, AND PEAK DURING THE DAYLIGHT HOURS ON  
SATURDAY, ESPECIALLY WEST OF INTERSTATE 25.  
 
SUNDAY...SIMILAR TEMPERATURES TO SATURDAY IN THE WAKE OF THE  
SHORTWAVE TROUGH ALOFT AND COLD FRONT, THOUGH IT WILL BE DRIER WITH  
NORTH FLOW ALOFT. BREEZY TO WINDY PER PROGGED SURFACE THROUGH 700 MB  
GRADIENTS.  
 
MONDAY...QUITE WINDY AND A BIT WARMER AS THE FLOW ALOFT BACKS TO  
NORTHWEST AND STRENGTHENS SIGNIFICANTLY. ALTHOUGH THERE WILL BE  
SCATTERED TO BROKEN MIDDLE AND HIGH CLOUDS IN THE MOIST FLOW ALOFT,  
NO PRECIPITATION IS EXPECTED DUE TO RELATIVELY DRY LOW LEVELS AND  
DOWNSLOPE LOW LEVEL WINDS.  
 

 
   
AVIATION
 
(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING)  
ISSUED AT 420 AM MST TUE DEC 12 2017  
 
VFR. WIND GUSTS TO 30 KNOTS...MAINLY BEFORE 00Z.  
 

 
   
FIRE WEATHER
 
 
ISSUED AT 300 AM MST TUE DEC 12 2017  
 
SUNNY AND DRY TODAY ACROSS SOUTHEAST WYOMING AND NEBRASKA  
PANHANDLE. LESS WIND EXPECTED TODAY OVER WHAT WE HAVE BEEN  
EXPERIENCING THE PAST SEVERAL DAYS IN THE PANHANDLE. THAT WILL  
CHANGE WEDNESDAY AS ANOTHER CLIPPER SYSTEM TRACKS ACROSS SOUTH  
DAKOTA AND EASTERN NEBRASKA. NORTHWEST WINDS IN THE PANHANDLE AND  
EAST OF THE LARAMIE RANGE EXPECTED TO INCREASE LATER TONIGHT AND  
THROUGH MUCH OF WEDNESDAY. TIMING OF THE CLIPPER SYSTEM SHOULD  
ALLOW COLDER AIR TO MOVE INTO THE AREA AND KEEP AFTERNOON HUMIDITY  
ABOVE CRITICAL LEVELS, SO CRITICAL FIRE WEATHER CONDITIONS ARE NOT  
EXPECTED.  
 

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

 
 

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