Area Forecast Discussion
Issued by NWS Cheyenne, WY

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111
FXUS65 KCYS 261805
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
1205 PM MDT TUE APR 26 2016

.UPDATE...
ISSUED AT 1131 AM MDT TUE APR 26 2016

SNOW IS BEGINNING TO LET UP IN INTENSITY IN LARAMIE/ALBANY
COUNTIES AS THE BEST LIFT SHIFTS NORTHWARD. THE MODELS CONTINUE TO
SHOW QPF DROPPING OFF OVER SOUTHEAST WY BY LATE THIS AFTN. CURRENT
HIGHLIGHTS ON TRACK AND WILL NOT MAKE ANY CHANGES WITH THE MORNING
PACKAGE. WEBCAMS SHOW SNOW NOT REALLY STICKING TO THE ROADS. LOWERED
HIGHS MORE IN LINE WITH THE CONSSHORT.

&&

.SHORT TERM...(TODAY THROUGH WEDNESDAY NIGHT)
ISSUED AT 320 AM MDT TUE APR 26 2016

PRETTY ACTIVE NIGHT ACROSS THE AREA WITH WIDESPREAD THUNDERSTORMS
OVER THE SOUTHERN NEBRASKA PANHANDLE AND FAR SOUTHEAST WYOMING...A
STRONG SQUALL LINE PUSHING ACROSS I25 FROM CHUGWATER TO
CHEYENNE...AND MODERATE TO HEAVY SNOWFALL TO THE WEST. LAPS
SURFACE ANALYSIS SHOWS AN INTENSIFYING AREA OF LOW PRESSURE ACROSS
NORTHEAST COLORADO WITH ALL MODELS SHOWING STRONG UPPER LEVEL
DIFFLUENCE AHEAD OF A POTENT UPPER LEVEL LOW CURRENTLY MOVING INTO
WESTERN COLORADO AT THIS HOUR. BASED ON THE CURRENT IR WATER VAPOR
LOOP...THIS LOW SEEMS TO HAVE STALLED EARLY THIS MORNING PRODUCING
WIDESPREAD PRECIPITATION ACROSS MOST OF THE AREA. RAIN IS CHANGING
TO SNOW AS FAR EAST AS THE I25 CORRIDOR WITH SNOW NOW MIXING IN
WITH RAIN/GRAUPEL IN CHEYENNE AT THIS HOUR. EXTENDED THE WINTER
STORM WARNING TO INCLUDE THE ARLINGTON/ELK MOUNTAIN AREA WITH
HEAVY SNOW BEING REPORTED IN THOSE LOCATIONS WITH VISIBILITIES
AROUND ONE HALF MILE AND SNOW COVERED ROADS. ISSUED A WINTER
WEATHER ADVISORY FOR THE LOWER ELEVATIONS OF CARBON
COUNTY...INCLUDING RAWLINS AND SARATOGA. WILL NEED TO CLOSELY
MONITOR THE LARAMIE VALLEY FOR A POSSIBLE ADVISORY OR WARNING WITH
MODERATE SNOW AND 32 DEGREES REPORTED AT LARAMIE...BUT CURRENT
RADAR SHOWS INTENSITY OF PRECIP LOWERING OVER THE NEXT FEW HOURS
AS DOWNSLOPE WINDS DEVELOP ACROSS THE LARAMIE VALLEY.
OTHERWISE...CURRENT HEADLINES LOOK GOOD AT THIS TIME AND WILL JUST
NEED TO CLOSELY MONITOR SNOWFALL RATES AND SNOWLEVELS THIS
MORNING.

UPPER LEVEL LOW IS FORECAST TO SLOWLY LIFT NORTH BY THIS
AFTERNOON...WITH PRECIPITATION RATES GRADUALLY LOWERING THROUGH
THE AFTERNOON. WITH SNOWFALL RATES DECREASING...MAY NEED TO CANCEL
WINTER WEATHER HEADLINES EARLY SINCE SNOW WILL STRUGGLE TO
ACCUMULATE ON ROADWAYS...ESPECIALLY THE LOWER ELEVATIONS. THE NEXT
FORECAST CHALLENGE WILL BE WHAT HAPPENS TO THE UPPER LEVEL LOW AS
IT REDEVELOPS TO THE SOUTHEAST LATE TONIGHT AND INTO WEDNESDAY
MORNING. MODELS SHOW ANOTHER ROUND OF PRECIPITATION ACROSS THE
EASTERN HIGH PLAINS ON WEDNESDAY...WITH SNOW POSSIBLE ACROSS THE
WESTERN NEBRASKA PANHANDLE AS SOME COLDER AIR FROM SOUTHERN CANADA
ATTEMPTS TO PUSH SOUTHWARD INTO THE AREA. HOWEVER...SNOW WILL
STRUGGLE TO ACCUMULATE DURING THE DAY SO EXPECT ANY ACCUMULATION
TO STAY ON ELEVATED AND GRASSY SURFACES. BY LATE
WEDNESDAY...MODELS SHOW THIS STUBBORN LOW FINALLY DRIFTING EAST
AND WEAKENING. HOWEVER...THE NEXT STORM SYSTEM WILL BE QUICK TO
FOLLOW AND WILL ALREADY BE DEVELOPING ACROSS THE SOUTHERN GREAT
BASIN REGION LATE WEDNESDAY NIGHT.

.LONG TERM...(THURSDAY THROUGH MONDAY)
ISSUED AT 330 AM MDT TUE APR 26 2016

COOL AND MOIST CONDITION WILL CONTINUE ACROSS THE CWA THURSDAY
THROUGH THE WEEKEND. SHOWERS SHOULD BEGIN SPREADING ACROSS THE
AREA THURSDAY AS YET ANOTHER UPPER LOW DROPS INTO THE DESERT SW
THURSDAY THEN MOVES SLOWLY EAST AND NORTHEAST INTO THE CENTRAL
HIGH PLAINS BY SATURDAY MORNING. GFS A BIT FARTHER SOUTH THAN THE
EC NOT CRITICALLY DIFFERENT. THICKNESSES WILL CONTINUE TO FAVOR
PERIODS OF SNOW OVER THE MTNS WITH MAINLY RAIN ACROSS LOWER
ELEVATIONS. UPPER SYSTEM LOOKS TO STALL OVER THE CENTRAL PLAINS
SATURDAY THROUGH SUNDAY WITH WRAP-AROUND PCPN CONTINUING ACROSS
MUCH OF THE CWA. SYSTEM SHOULD FINALLY BEGIN TO MOVE AWAY MONDAY
WITH SHOWERS GRADUALLY COMING TO AN END. WILL CONTINUE TO
UNDERCUT GUIDANCE TEMPS MAINLY FOR MAX TEMPERATURES GIVEN PLENTY
OF CLOUD COVER AND PCPN.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 1205 PM MDT TUE APR 26 2016

WYOMING TAFS...IMPROVING TO MVFR THIS AFTERNOON...THEN BECOMING IFR
AGAIN OVERNIGHT IN FOG...AND IMPROVING AGAIN TO MVFR AND VFR AFTER
15Z ON WEDNESDAY.

NEBRASKA TAFS...MOSTLY IFR PREVAILING THIS AFTERNOON WITH IFR
OVERNIGHT...IMPROVING TO MVFR AFTER 15Z WEDNESDAY.

&&

.FIRE WEATHER...
ISSUED AT 251 AM MDT TUE APR 26 2016

NO FIRE WEATHER CONCERNS THROUGH THE WEEK AND INTO NEXT WEEKEND. AN
ACTIVE WEATHER PATTERN WILL RESULT IN WIDESPREAD RAINFALL AND MOUNTAIN
SNOW THROUGH THE WEEK AND INTO NEXT WEEKEND. COOLER THAN NORMAL
TEMPERATURES AND HIGH HUMIDITIES ARE EXPECTED THROUGH SUNDAY.

&&

.CYS WATCHES/WARNINGS/ADVISORIES...
WY...WINTER STORM WARNING UNTIL MIDNIGHT MDT TONIGHT FOR WYZ101-
     103>105-110-112-114-116.

     WINTER WEATHER ADVISORY UNTIL 3 PM MDT THIS AFTERNOON FOR WYZ102-
     106-107-109-113-117-118.

     WINTER STORM WARNING UNTIL 3 PM MDT THIS AFTERNOON FOR WYZ115.

NE...NONE.
&&

$$

UPDATE...ZF
SHORT TERM...TJT
LONG TERM...RE
AVIATION...RUBIN
FIRE WEATHER...TJT



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