Area Forecast Discussion
Issued by NWS Cheyenne, WY

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000
FXUS65 KCYS 242129
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
329 PM MDT SUN APR 24 2016

.SHORT TERM...(THIS EVENING THROUGH TUESDAY NIGHT)
ISSUED AT 234 PM MDT SUN APR 24 2016

STRONG UPPER LOW IS CURRENTLY LOCATED OVER EXTREME SOUTHWESTERN
SOUTH DAKOTA.  IR IMAGERY SHOWS CLOUD TOPS WARMING ACROSS SOUTHEAST
WYOMING AND THE SOUTHERN NEBRASKA PANHANDLE.  WENT AHEAD AND
CANCELLED THE WINTER WEATHER ADVISORY OVER SOUTHEAST WYOMING WITH
SNOW BEGINNING TO WIND DOWN.  THE MODELS SHOW LITTLE QPF AFTER 00Z.
HIGH WINDS HAVE FAILED TO MATERIALIZE OVER SOUTHEAST WYOMING THIS
AFTN WITH THE CLOUD COVER INHIBITING MIXING.  A FEW GUSTS OF 50-55
MPH HAVE OCCURRED IN THE ARLINGTON AREA AND SOUTHERN LARAMIE RANGE
OVER THE PAST FEW HOURS. THE VAD WIND PROFILE AT CYS SHOWS 45-50
KTS AT 3000 FT AGL. IT HAS JUST BEEN DIFFICULT TO TAP INTO THESE
STRONGER WINDS ALOFT DUE TO THE POOR LLVL LAPSE RATES. WILL DROP
THE HIGH WIND HIGHLIGHTS AS THE GRADIENT AND WINDS ALOFT ONLY
DECREASE THROUGH 00Z.

WILL BE BETWEEN SYSTEMS FOR MUCH OF THE DAY ON MONDAY.  TEMPS WILL
BE AROUND 10 DEGREES WARMER THAN TODAY.  NEXT UPPER TROUGH WILL
QUICKLY DIG INTO UTAH BY THE AFTN...CAUSING EAST TO SOUTHEAST WINDS
TO DEVELOP AT THE SFC.  MODEL CONSENSUS HAS THE CLOSED LOW LIFTING
NORTHEASTWARD TOWARD THE WY-NE BORDER BY TUESDAY.  WIDESPREAD PRECIP
WILL DEVELOP OVER THE REGION BY MON NIGHT AS LARGE SCALE ASCENT
INCREASES.  BOTH THE GFS AND ECMWF SHOW WET BULB ZERO HEIGHTS
REMAINING ALOFT FOR AREAS TO THE EAST OF THE LARAMIE RANGE THROUGH
00Z WED.  THUS CURRENT THINKING IS THAT SNOW WILL BE LIMITED ACROSS
THE PLAINS.  OF COURSE ALONG AND WEST OF THE LARAMIE RANGE SNOW
ACCUMULATIONS WILL BE TRICKIER.  THE BEST CHANCE OF WARNING
ACCUMULATIONS MAY BE OVER THE NORTHERN LARAMIE RANGE AND NORTHERN
CARBON/ALBANY COUNTIES.  WILL LET FUTURE SHIFTS DECIDE ON WINTER
WEATHER HIGHLIGHTS OVER SOUTHEAST WY.

.LONG TERM...(WEDNESDAY THROUGH SUNDAY)
ISSUED AT 234 PM MDT SUN APR 24 2016

A COOL AND UNSETTLED WEATHER PATTERN IS STILL ON TRACK THROUGH THE
LONG TERM FORECAST PERIOD. LINGERING RAIN AND SNOW SHOWERS ARE
STILL POSSIBLE WEDNESDAY AS A SLOW MOVING UPPER LEVEL LOW SHIFTS
INTO THE PLAIN. AS THE FIRST UPPER LOW DEPARTS...THE NEXT UPPER
LOW WILL BEGIN TO MOVE INTO THE REGION. MORE SHOWERS ARE POSSIBLE
BY THURSDAY AND STRAIGHT THROUGH THE WEEKEND AS A BROAD TROUGH
WILL BE IN PLACE ACROSS THE WESTERN CONUS. THE MAIN FORECAST
UNCERTAINTY WILL BE TIMING...PLACEMENT...AND STRENGTH OF AN GIVEN
PIECE OF UPPER LEVEL ENERGY...ALL OF WHICH CAN MAKE FOR BIG
DIFFERENCES IN TEMPERATURES AND PRECIPITATION CHANCES ON ANY GIVEN
DAY.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 234 PM MDT SUN APR 24 2016

AN UPPER LEVEL LOW OVER SOUTHEAST WYOMING AS OF 18Z WILL QUICKLY
MOVE INTO THE NORTHERN PLAINS BY THIS EVENING. WIDESPREAD RAIN AND
SNOW OVER SOUTHEAST WYOMING WILL END THIS EVENING WITH ONLY A FEW
LINGERING RAIN AND SNOW SHOWERS BETWEEN 00Z AND 06Z THIS EVENING.

CURRENTLY SNOW IS PRODUCING IFR CIGS AND VISIBILITY ACROSS THE
MOUNTAINS OF SOUTHEAST WYOMING AND ADJACENT AREAS. ALSO WINDS
UPWARDS OF 50 MPH ARE FURTHER REDUCING VISIBILITIES. WINDS WILL
ALSO SUBSIDE THIS EVENING WITH WINDS BECOMING LIGHT AFTER 06Z.

&&

.FIRE WEATHER...
ISSUED AT 234 PM MDT SUN APR 24 2016

NO FIRE WEATHER CONCERNS THROUGH NEXT WEEK.  BELOW NORMAL
TEMPERATURES AND A MOIST AIRMASS WILL KEEP MINIMUM AFTERNOON
HUMIDITY VALUES MOSTLY ABOVE 40 PERCENT.  WIDESPREAD PRECIPITATION
WILL FALL MONDAY NIGHT THROUGH WEDNESDAY MORNING ACROSS THE REGION.

&&

.CYS WATCHES/WARNINGS/ADVISORIES...

WY...NONE.

NE...NONE.

&&

$$

SHORT TERM...ZF
LONG TERM...SML
AVIATION...SML
FIRE WEATHER...ZF



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