Area Forecast Discussion
Issued by NWS Cheyenne, WY

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000
FXUS65 KCYS 010001
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
600 PM MDT THU APR 30 2015

.SHORT TERM...(THIS EVENING THROUGH SATURDAY NIGHT)
ISSUED AT 345 PM MDT THU APR 30 2015

SHOWERS AND ISOLATED THUNDERSTORMS HAVE DEVELOPED OVER THE HIGHER
ELEVATIONS OF SOUTHEAST WYOMING THIS AFTERNOON. THIS ACTIVITY WILL
CONTINUE THROUGH THE AFTERNOON AND INTO THE EVENING HOURS. AN
UPPER LEVEL JET AND MIDLEVEL SHORTWAVE ENERGY WILL AID IN SHOWER
AND THUNDERSTORM DEVELOP INTO THIS EVENING...BUT BY LATE THIS
EVENING MOST ACTIVITY WILL DIE OFF AS THE BOUNDARY LAYER
STABILIZES. THREAT OF SEVERE STORMS IS ON THE LOW SIDE TODAY. A
FEW STORMS WILL PRODUCE SMALL HAIL AND GUSTY WINDS. A DEEPER
INVERSION WILL MAKE IT DIFFICULT FOR STORMS TO FORM ACROSS THE FAR
NORTHERN PORTIONS OF THE FORECAST AREA TODAY/TONIGHT WITH MOST
ACTIVITY ROUGHLY ALONG AND SOUTH OF A LINE FROM GLENDO WY TO
CRAWFORD NE.

THERE IS ANOTHER CHANCE FOR SHOWERS AND THUNDERSTORMS AGAIN ON
FRIDAY BUT OVER A MORE CONFINED AREA. MAIN CHANCES WILL BE IN THE
AFTERNOON OVER ALBANY...CARBON...AND LARAMIE COUNTY. ISENTROPIC
FORCING ALONG A MID LEVEL BOUNDARY WILL BE THE MAIN FOCUSING
FEATURE. SHEAR VALUES WILL BE A BIT STRONGER TOMORROW BUT CAPE
VALUES WILL BE ON THE LOWER END...SO AGAIN THE THREAT FOR SEVERE
THUNDERSTORMS WILL BE ON THE LOWER SIDE. ISOLATED TO SCATTERED
SHOWERS AND THUNDERSTORMS LOOK LIKE A GOOD BET AGAIN SATURDAY
AFTERNOON AND EVENING AS WEAK SHORTWAVE ENERGY MOVES OVER THE
AREA. WEAK UPPER LEVEL SUPPORT WILL COMBINED WITH STEEP LOW LEVEL
LAPSE RATES TO PRODUCE CONVECTION. AGAIN THE OVERALL THREAT OF
SEVERE WEATHER LOOKS TO BE ON THE LOW SIDE.

.LONG TERM...(SUNDAY THROUGH THURSDAY)
ISSUED AT 330 PM MDT THU APR 30 2015

A VERY UNSETTLED WEATHER PATTERN APPEARS LIKELY THROUGH THE EXTENDED
PERIOD. A WEAK SURFACE BOUNDARY DRAPED FROM NORTH TO SOUTH ALONG THE
LARAMIE RANGE WILL SERVE AS THE FOCUS FOR SCATTERED SHOWERS AS WELL
AS A FEW TSTMS WITH WEAK SBCAPE PROGGED BY THE GFS. THERMAL PROFILES
REMAIN WARM INTO EARLY NEXT WEEK...WITH H7 TEMPS AVERAGING +3 TO +5
DEG C THROUGH MON. WIDESPREAD CLOUD COVER AND LOW-LEVEL UPSLOPE WILL
MOST LIKELY KEEP TEMPERATURES OUT OF THE 70S THOUGH. BY WED...GFS/EC
BOTH SUGGEST A VIGOROUS UPPER-LEVEL LOW TRACKING ACROSS THE PACIFIC
NORTHWEST. THIS COULD SERVE AS A KICKER SYSTEM FOR A SECOND...WEAKER
DISTURBANCE OVER SOUTHERN AZ/NM ON TUE. INCREASING GULF MOISTURE AND
LARGER SCALE DYNAMIC FORCING WILL MOST LIKELY YIELD DAILY CONVECTION
WHICH COULD CARRY OVER WELL AFTER DARK. KEPT THUNDER CONFINED TO THE
DAYTIME HOURS AS MODEST (500-1000 J/KG) CAPES DROP TO NEAR NIL AFTER
DARK PER THE GFS. THE MODELS SHOW GENERALLY WEAK FLOW ALOFT THROUGH
THE PERIOD WITH LESS THAN 30 KTS AT H5. AS SUCH...DO NOT EXPECT ANY
ORGANIZED SEVERE WEATHER DAYS ATTM WITH MEAGER VERTICAL SHEAR.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH FRIDAY AFTERNOON)

VFR CONDITIONS EXPECTED OUTSIDE OF THUNDERSTORMS. ISOLATED TO WIDELY
SCATTERED SHOWERS AND STORMS WILL CONTINUE ACROSS MAINLY SOUTHEAST
WYOMING THIS EVENING...WITH SHOWERS BECOMING MORE WIDESPREAD OVER
THE WESTERN PANHANDLE DURING THE EVENING AND OVERNIGHT. ANY SHOWERS
AND THUNDERSTORMS COULD BE ACCOMPANIED BY GUSTY/ERRATIC WINDS AND
BRIEF MVFR VSBYS. ANOTHER ROUND OF SHOWERS AND TSTORMS ARE EXPECTED
BY FRIDAY AFTERNOON AS WELL.

&&

.FIRE WEATHER...
ISSUED AT 326 PM MDT THU APR 30 2015

AN ACTIVE WEATHER PATTERN WILL SETTLE INTO THE FORECAST AREA OVER
THE NEXT SEVERAL DAYS. A BROAD TROUGH WILL MOVE INTO THE WESTERN
CONUS BY EARLY NEXT WEEK AND REMAIN IN PLACE THROUGH THE WEEK.
THIS MEANS CHANCES FOR SHOWERS AND THUNDERSTORMS EVERY DAYS WITH
THE MAIN CHANCES IN THE AFTERNOON AND EVENING. SHOWER ACTIVITY
WILL CONTINUE TO SUPPORT GREEN UP ACROSS THE AREA WITH NO CONCERNS
OF CRITICAL FIRE CONDITIONS IN THE FORESEEABLE FUTURE.


&&

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

&&

$$

SHORT TERM...SML
LONG TERM...CLH
AVIATION...CLH/TJT
FIRE WEATHER...SML


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