820  
FXUS65 KCYS 260324  
AFDCYS  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE CHEYENNE WY  
924 PM MDT SAT JUN 25 2016  
   
UPDATE
 
 
ISSUED AT 835 PM MDT SAT JUN 25 2016  
 
WINDS HAVE EASED ACROSS SOUTHEAST WYOMING THIS EVENING. LOOKING AT  
WINDS AND RH LEVELS IN FWZ 301...THEY HAVE REALLY COME DOWN TO  
AROUND 10MPH AND HUMDITIES HAVE CLIMBED BACK TO...OR ABOVE 15  
PERCENT. WENT AHEAD AND LET THE RFW EXPIRE ON TIME AT 8PM.  
 

 
   
SHORT TERM
 
(TONIGHT - MONDAY NIGHT)  
ISSUED AT 326 PM MDT SAT JUN 25 2016  
 
THE LATEST KCYS RADAR LOOP SHOWS NUMEROUS SURFACE OUTFLOW BOUNDARIES  
ACROSS LARAMIE COUNTY. THIS HAS ALREADY TRIGGERED A FEW SHOWERS AND/  
OR WEAK THUNDERSTORMS ALONG AND SOUTH OF I-80, SO THIS FORCING COULD  
YIELD ADDITIONAL ACTIVITY THROUGH EARLY EVENING. WEAK INSTABILITY IS  
EXPECTED TO LIMIT STORM COVERAGE/INTENSITY WITH MAXIMUM CAPES AROUND  
500 J/KG. QUASI-ZONAL FLOW ALOFT CONTINUES ON SUNDAY WITH A FEW WEAK  
DISTURBANCES TRAVERSING THE FLOW. UPSLOPE FLOW ALONG AND EAST OF THE  
LARAMIE RANGE SHOULD BRING DEW POINTS BACK INTO THE MID/UPPER 40S ON  
THE HIGH PLAINS BEFORE AFTERNOON MIXING YIELDS SOME LOW-LEVEL DRYING  
AFTER 18Z. CONVECTIVE COVERAGE SHOULD BE HIGHER TOMORROW, BUT EXPECT  
ANOTHER DAY OF MODEST INSTABILITY WITH VERY LITTLE RISK FOR STRONGER  
STORMS. INVERTED-V SOUNDING PROFILES WITH CLOUD BASES BETWEEN 10-15K  
FEET SUGGESTS GUSTY WINDS AS THE PRIMARY HAZARD, SO CAN NOT RULE OUT  
A COUPLE OF 50 KNOT GUSTS. BETTER CHANCES FOR MORE WIDESPREAD SEVERE  
STORMS ARRIVE ON MONDAY WITH A STRONGER WAVE RIDING THE EDGE OF DEEP  
UPPER-LEVEL RIDGING CENTERED OVER THE 4 CORNERS. GFS AND NAM SUGGEST  
DEW POINTS IN THE 50S TO NEAR 60 OVER THE PLAINS WITH GOOD LOW-LEVEL  
VEERING AND MUCAPES AROUND 2000 J/KG AND 0-6 KM SHEAR VECTORS OF 40-  
50 KNOTS. THE COMBINATION OF COOLING TEMPERATURES ALOFT, CONVERGENCE  
IN THE LOW-LEVELS, AND SURFACE UPSLOPE SHOULD SUPPORT THE INITIATION  
OF THUNDERSTORMS, SOME OF WHICH MAY RAPIDLY BECOME SUPERCELLS. DAY 3  
SPC OUTLOOK HAS A SLIGHT RISK OVER THE I-80 CORRIDOR, BUT SHOULD SEE  
THIS EXPANDED FARTHER NORTH AND WEST IN THE FUTURE IF MODEL GUIDANCE  
COMES INTO BETTER AGREEMENT. OVERALL TEMPERATURES SHOULD BE NEAR OUR  
CLIMATOLOGICAL NORMALS WITH WEST TO NORTHWEST FLOW IN THE MID-LEVELS  
OVER THE CWA.  
   
LONG TERM
 
(TUESDAY THROUGH SATURDAY)  
ISSUED AT 326 PM MDT SAT JUN 25 2016  
 
THE SUMMER PATTERN WILL PERSIST THROUGH MUCH OF NEXT WEEK AS FAIRLY  
WEAK RIDGE AXIS REMAINS CENTERED OVR THE FOUR CORNERS. MID-LEVEL  
MOISTURE ALONG WITH A SERIES OF DISTURBANCES WILL RIDE THE TOP OF  
THE RIDGE PRODUCING NEARLY DAILY MAINLY AFTERNOON/EVENING SHOWER AND  
THUNDERSTORM CHANCES. INSTABILITY AND SHEAR WILL BE SUFFICIENT ON  
TUESDAY AND WEDNESDAY FOR SEVERE THUNDERSTORM POTENTIAL MAINLY IN  
AREAS ALONG AND EAST OF THE LARAMIE RANGE. CAN'T COMPLETELY RULE OUT  
STRONG-SEVERE POTENTIAL THE OTHER DAYS EITHER, BUT CHANCES WILL BE  
LESS GIVEN LIMITED PROGD SHEAR PARAMETERS. TEMPERATURES WILL BE  
RIGHT AT SEASONAL NORMALS NEXT WEEK AS WELL WITH HIGHS REACHING  
AROUND 80F FOR LOCATIONS ABOVE 5000 FEET AND 80S TO NEAR 90 FOR  
ELEVATIONS BELOW.  
 

 
   
AVIATION
 
(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)  
ISSUED AT 922 PM MDT SAT JUN 25 2016  
 
VFR OVERNIGHT AS CONVECTION CONTINUES TO DISSIPATE OVER LARAMIE  
COUNTY. MORE SCATTERED SHOWERS AND THUNDERSTORMS EXPECTED SUNDAY  
AFTERNOON FOR OUR NEBRASKA PANHANDLE AIRPORTS AS WELL AS KCYS.  
INTRODUCED VCTS WORDING IN THE 06Z TAFS FOR THESE AIRPORTS THAT  
WILL GO INTO SUNDAY EVENING.  
 

 
   
FIRE WEATHER
 
 
ISSUED AT 326 PM MDT SAT JUN 25 2016  
 
CRITICAL OR NEAR-CRITICAL FIRE WEATHER CONDITIONS WILL CONTINUE THIS  
AFTERNOON AND EARLY EVENING FOR FWZ 301 WITH WARM TEMPERATURES, VERY  
DRY AIR AND GUSTY WINDS. WINDS WILL BE LOWER ON SUNDAY AND MONDAY W/  
INCREASING CHANCES FOR SHOWERS AND THUNDERSTORMS ESPECIALLY OVER THE  
HIGH PLAINS.  
 

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

 
 

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