839  
FXUS65 KCYS 010626  
AFDCYS  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE CHEYENNE WY  
1226 AM MDT WED JUL 1 2015  
   
SHORT TERM
 
(THIS EVENING THROUGH THURSDAY NIGHT)  
ISSUED AT 230 PM MDT TUE JUN 30 2015  
 
SURFACE ANALYSIS SHOWING A FRONTAL BOUNDARY OVER WESTERN SOUTH  
DAKOTA...EXTENDING INTO EXTREME NORTHEASTERN WYOMING EARLY THIS  
AFTERNOON. RADAR SHOWING SOME SHOWERS DEVELOPING OVER THE NORTH  
LARAMIE RANGE THIS AFTERNOON. LAPRELLE CREEK AND WINDY PEAK  
SNOTELS SHOWING SOME PRETTY GOOD RAINFALL AMOUNTS IN THE NORTH  
LARAMIE RANGE. BUT OUTSIDE THIS AREA...IT STILL LOOKS LIKE ECHOES  
ARE ELEVATED. 1PM HUMIDITY AT CHEYENNE AT 19 PERCENT...DOUGLAS AT  
24 PERCENT...LARAMIE 21 PERCENT...SO THESE ECHOES ARE GOING TO  
TAKE QUITE A WHILE TO REACH THE GROUND. SO FOR THIS  
AFTERNOON...THINK MOST PLACES WILL REMAIN DRY UNTIL THE LATE  
AFTERNOON HOURS. LATEST SPC MESOANALYSIS SHOWING AROUND 500J/KG  
CAPE ACROSS SOUTHERN WYOMING. NIOBRARA COUNTY AND THE PANHANDLE  
JUST LOST THEIR CAP OUT THAT WAY WITH CAPE VALUES AROUND 1000J/KG.  
JUST NORTH OF THE PANHANDLE NEAR THE FRONT...SURFACE BASED CAPES  
OF 2500 TO 3500 J/KG EXISTS. LOOKS LIKE THE SLIGHT RISK AREA IS  
STILL HOLDING GOOD UP THAT WAY.  
 
LATEST HRRR SIMULATED RADAR SHOWS INCREASING AREA OF SHOWERS AND  
THUNDERSTORMS MOVING SOUTHEAST LATE THIS AFTERNOON THAT MOVE INTO  
THE PANHANDLE THROUGH THE EARLY EVENING HOURS. CONTINUE THE CHANCE  
POP FORECAST FOR THIS AFTERNOON WITH SMALL HAIL AND GUSTY WINDS.  
COULD SEE A COUPLE SEVERE STORMS MOVE INTO THE NORTHERN PANHANDLE  
FROM WESTERN SOUTH DAKOTA/NORTHEASTERN WYOMING. OVERALL  
THOUGH...DO THINK CHANCES WILL BE LOW.  
 
BETTER CHANCES APPEAR FOR WEDNESDAY AFTERNOON FOR LOCATIONS ALONG  
THE INTERSTATE 80 CORRIDOR AS THE FRONT STALLS ALONG THE LARAMIE  
RANGE. THIS IS DEPICTED ON THE ECMWF. GFS HAS FRONT FURTHER EAST  
IN NEBRASKA. DUE TO THE DIFFERENCES...DI NOT CHANGE POPS TOO MUCH  
FOR WEDNESDAY WITH CHANCE POPS.  
 
DID INCREASE POPS FOR THE PANHANDLE WEDNESDAY NIGHT INTO THURSDAY  
MORNING. ECMWF SHOWING FRONT LIFTING ENE INTO WESTERN NEBRASKA.  
NAM SOUNDINGS FOR THE PANHANDLE SHOWING PWATS ALMOST TO 1.3 INCHES  
WITH LONG/SKINNY CAPE PROFILES. GOOD NEWS IS FORECAST STORM  
MOTIONS ARE FAIRLY HIGH...SO DO THINK WE ARE OK FOR POSSIBLE HEAVY  
RAIN THREAT DURING THAT TIME.  
   
LONG TERM
 
(FRIDAY THROUGH TUESDAY)  
ISSUED AT 230 PM MDT TUE JUN 30 2015  
 
ELONGATED UPPER RIDGE WILL HOLD ACROSS THE SW CONUS THIS PERIOD  
WITH A GENERALLY NWLY FLOW ALOFT OVER THE CWA ON THE NORTHEAST  
PERIPHERY OF THE UPPER HIGH. MAINLY DRY CONDITIONS ARE EXPECTED  
FRIDAY THROUGH THE WEEKEND THOUGH BY SUNDAY INTO EARLY NEXT WEEK  
CONVECTION SHOULD INCREASE AS BETTER MOISTURE ADVECTS INTO THE  
REGION FROM THE SW. A COOL FRONT IS EXPECTED TO PASS ACROSS SUNDAY  
BRINGING A MODEST COOL DOWN INTO MONDAY BEFORE TEMPS REBOUND  
TUESDAY. POST FRONTAL UPSLOPE PATTERN SHOULD HELP PCPN CHANCES  
MONDAY WITH CHANCES FOR SHOWERS AND TSTMS CONTINUING TUESDAY.  
 

 
   
AVIATION
 
(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)  
ISSUED AT 1225 AM MDT WED JUL 1 2015  
 
ISOLATED TO WIDELY SCATTERED THUNDERSTORMS THROUGH 07Z FOR  
SIDNEY TAF SITES...OTHERWISE VFR OVERNIGHT. THUNDERSTORMS  
PRODUCING LOCALIZED WIND GUSTS TO 45 KNOTS...TURBULENCE AND MVFR.  
 
VFR ON WEDNESDAY WITH WIDELY SCATTERED AFTERNOON THUNDERSTORMS  
FOR THE WYOMING TAF SITES PRODUCING LOCALIZED WIND GUSTS TO  
35 KNOTS AND MVFR.  
 

 
   
FIRE WEATHER
 
 
ISSUED AT 230 PM MDT TUE JUN 30 2015  
 
NORTH LARAMIE RANGE SEEING WETTING RAINS EARLY THIS AFTERNOON WITH  
SHOWERS AND THUNDERSTORMS MOVING SOUTHEAST ALONG A FRONTAL  
BOUNDARY MOVING INTO THE AREA FROM THE NORTH. FOR AREAS EAST OF  
THE LARAMIE RANGE...IT WILL TAKE SOME TIME FOR SHOWERS TO REACH  
THE GROUND AS AFTERNOON HUMIDITIES QUITE LOW. EVENTUALLY  
THOUGH...MUCH OF SOUTHERN WYOMING AND SOUTHERN NEBRASKA PANHANDLE  
SHOULD SEE WETTING RAINS LATE AFTERNOON THROUGH EARLY EVENING.  
BETTER CHANCES WEDNESDAY AFTERNOON AS THE FRONT STALLS ALONG THE  
EAST SLOPES OF THE LARAMIE RANGE. NO FIRE WEATHER CONCERNS THROUGH  
THE WEEK AS AFTERNOON HUMIDITIES SHOULD REMAIN ABOVE CRITICAL  
LEVELS AND FUELS ARE GREEN.  
 

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

 
 

 
 
SHORT TERM...GCC  
LONG TERM...RE  
AVIATION...SAR  
FIRE WEATHER...GCC  
 
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