Area Forecast Discussion
Issued by NWS Cheyenne, WY

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816
FXUS65 KCYS 051805
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
1205 PM MDT THU MAY 5 2016

.SHORT TERM...(TODAY THROUGH SATURDAY NIGHT)
ISSUED AT 258 AM MDT THU MAY 5 2016

ANOTHER NICE DAY IN STORE WITH CONDITIONS VERY SIMILAR TO YESTERDAY.
THE UPPER RIDGE AXIS WILL BE OVERHEAD WITH WEAK WINDS.  HIGHS WILL
BE A FEW DAYS WARMER THAN WEDNESDAY.  THE GFS SHOWS LI VALUES OF 0C
TO -2C OVER AREAS ALONG AND WEST OF THE LARAMIE RANGE...SO COULD SEE
AN ISOLATED SHOWER/TSTM NEAR THE HIGHER TERRAIN DURING THE AFTN. THE
PATTERN BEGINS TO CHANGE ON FRIDAY AS THE CLOSED UPPER LOW OVER THE
SOUTHWESTERN U.S. BEGINS TO INFLUENCE OUR WEATHER.  INSTABILITY IS
BETTER ON FRIDAY AFTN/EVENING AND WITH INCREASING UPPER LEVEL
DIFFLUENCE...WILL SEE SCATTERED CONVECTION DEVELOP OVER SOUTHEAST
WY.  THE STORMS COULD VERY WELL CONTINUE INTO THE EARLY NIGHT WITH
LLVL MOISTURE ADVECTION AND FORCING FROM A WEAK SHORTWAVE.

LLVL EASTERLY WINDS WILL OCCUR THROUGH SATURDAY WITH WIDESPREAD LOW
CLOUDS TO THE EAST OF THE LARAMIE RANGE.  THE PERSISTENT UPSLOPE AND
CLOUDINESS WILL MEAN TEMPS WILL BE 15-20 DEGREES COOLER.  THE MODELS
CONTINUE TO SHOW A STRONG SHORTWAVE LIFTING NORTHWARD FROM COLORADO
INTO OUR CWA BY SATURDAY EVENING.  WIDESPREAD STRATIFORM RAIN WITH
ISOLATED TSTMS WILL OCCUR ON LATE SATURDAY AFTN AND SATURDAY EVENING
OVER THE SOUTHERN HALF OF THE CWA.  RAISED POPS INTO THE 70-80
PERCENT RANGE.  THE RAIN WILL BE MODERATE TO LOCALLY HEAVY WITH GOOD
DEEP LAYER ASCENT.  WET BULB ZERO HEIGHTS DO FALL TO 8500-9000 FT BY
06Z SUNDAY...SO WILL LIKELY SEE A CHANGEOVER TO SNOW IN THE SIERRA
MADRE AND SNOWY RANGES.  HOWEVER NOT EXPECTING SIGNIFICANT
ACCUMULATIONS AS PRECIP WILL BE DECREASING IN INTENSITY BY LATE
SATURDAY NIGHT.

.LONG TERM...(SUNDAY THROUGH WEDNESDAY)
ISSUED AT 258 AM MDT THU MAY 5 2016

AN UNSETTLED WEATHER PATTERN IS LIKELY TO PERSIST THROUGH THE MIDDLE
OF NEXT WEEK WITH LARGE SCALE TROUGHING IN PLACE. WRAP-AROUND PRECIP
CAN BE EXPECTED ACROSS MUCH OF THE CWA ON SUN WITH LOW-LEVEL UPSLOPE
REMAINING INTACT OVER THE PLAINS AND DECENT MID-LEVEL PVA ASSOCIATED
WITH THE UPPER LOW. THAT SYSTEM MEANDERS SLOWLY EASTWARD ON MON WITH
ANOTHER PACIFIC SHORTWAVE QUICKLY ON ITS HEELS. THE GFS/ECMWF ARE IN
GOOD AGREEMENT WITH THE OVERALL PATTERN...SO WE EXPECT AT LEAST ISO/
SCT SHOWERS TO CONTINUE FOR TUE/WED. TEMPERATURES SHOULD BE SOMEWHAT
STEADY THROUGH THE PERIOD...GENERALLY IN THE 50S AND LOW 60S OUTSIDE
OF THE MOUNTAINS.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 1205 PM MDT THU MAY 5 2016

VFR CONDITIONS WILL PREVAIL THROUGH THE PERIOD WITH A STEADY
STREAM OF HIGH CIRRUS MOVING OVERHEAD FROM THE SOUTHWEST. SOME
GUSTY WEST-SOUTHWEST WINDS ARE POSSIBLE AT TIMES THIS
AFTERNOON...WITH WINDS BECOMING SOUTHERLY AND GUSTY ACROSS THE
PANHANDLE TONIGHT. RAIN SHOWERS WITH A FEW T-STORMS WILL BEGIN TO
SPREAD FROM SOUTHWEST TO NORTHEAST FRIDAY LATE MORNING.

&&

.FIRE WEATHER...
ISSUED AT 258 AM MDT THU MAY 5 2016

NO FIRE WEATHER CONCERNS THROUGH THE END OF THE WEEK. TEMPERATURES
WILL BE ABOVE NORMAL THROUGH FRIDAY.  MINIMUM HUMIDITY VALUES WILL
DROP TO AROUND 20 PERCENT THIS AFTERNOON...HOWEVER WINDS WILL BE
LIGHT. A GOOD CHANCE OF WIDESPREAD WETTING RAIN WILL OCCUR SATURDAY
AFTERNOON INTO SUNDAY MORNING.  TEMPERATURES WILL BE COOLER OVER THE
WEEKEND WITH INCREASING RELATIVE HUMIDITY.

&&

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

$$

SHORT TERM...ZF
LONG TERM...CLH
AVIATION...RJM
FIRE WEATHER...ZF



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