Area Forecast Discussion
Issued by NWS Cheyenne, WY

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724
FXUS65 KCYS 062333
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
533 PM MDT FRI MAY 6 2016

.SHORT TERM...(THIS EVENING THROUGH SATURDAY NIGHT)
ISSUED AT 526 PM MDT FRI MAY 6 2016

STRONG SPRING STORM STILL ON TRACK TO BRING THE POTENTIAL FOR
SEVERE THUNDERSTORMS...FLASH FLOODING...AND MOUNTAIN SNOWS TOMORROW.

FOR TODAY...A FEW STRONGER STORMS HAVE DEVELOPED ACROSS CARBON AND
ALBANY COUNTIES WITHIN OROGRAPHIC FORCING AND MODERATE...MOIST
SOUTHEAST FLOW. THE COLD FRONT LOOKS TO BE MAKING ITS WAY SOUTH
ACROSS WYOMING THIS AFTERNOON AND WILL AIDE IN DEVELOPING MORE
WIDESPREAD CONVECTION ACROSS THE EASTERN PLAINS THROUGH THIS EVENING
AS WELL. MODERATE INSTABILITY IN PLACE WILL ALLOW SOME STORMS TO
PRODUCE AT LEAST SMALL HAIL AND GUSTY WINDS...ALONG WITH MODERATE TO
HEAVY RAINFALL THROUGH THE EVENING. WOULD NOT BE SURPRISED TO SEE
SOME STORMS DROP AROUND 1 INCH OF QPF ESPECIALLY ACROSS THE EASTERN
PLAINS WHERE DEEP MOISTURE/ABOVE NORMAL PW`S WILL BE IN PLACE.

TURNING TO TOMORROW...MADE FEW CHANGES TO THE ONGOING FORECAST. THE
MAIN CHANGES WERE TO TIMING OF HEAVIEST RAINFALL...CHANGE-OVER TO
SNOW...AND OVERALL THREAT FOR SEVERE WEATHER. THINK THAT THE VORT
LOBE MOVING UP FROM COLORADO WILL BE A BIT QUICKER BASED ON 12Z
GUIDANCE...MEANING STRONGEST ACTIVITY AND HEAVIEST RAINFALL COULD
DEVELOP MORE MID-LATE AFTERNOON WITH A CHANGEOVER TO SNOW QUICKER VS
EVENING TIME FRAME. SNOW LEVELS STILL LOOK TO DROP TO ABOUT
8000FT IN THE LATE AFTERNOON THROUGH EVENING...AND PERHAPS EVEN TO
THE VALLEY FLOOR OVERNIGHT...WITH THE JUXTAPOSITION OF HIGHEST QPF
AND CHANGEOVER TO SNOW WILL BE SUCH THAT ACCUMULATIONS IN THE
HIGHER MOUNTAINS ARE MOST LIKELY TO REMAIN IN THE 6-10" RANGE WITH
LOCALLY HIGHER AMOUNTS.

INSTABILITY AND SHEAR PROGS CONTINUE TO LOOK FAVORABLE FOR SEVERE
WEATHER IN OUR SOUTHERN AND EASTERN COUNTIES TOMORROW AFTERNOON.
CONFIDENCE IS STEADILY INCREASING FOR THIS POTENTIAL. SOUNDINGS AND
HODOGRAPHS FROM CYS-SNY SHOW FAVORABLE TURNING IN THE LOW TO
MID LEVELS...WITH THE CAP STEADILY ERODING THROUGH THE MID-LATE
AFTERNOON...DEPENDING ON BURN OFF RATE OF TONIGHT`S NIGHT
STRATUS/FOG DEVELOPMENT IN UPSLOPE FLOW. SBCAPES COULD BE UPWARDS
OF 1500 J/KG...AND COMBINED WITH THE GOOD SHEAR PROFILE...STILL
THINK SUPERCELLS ARE A DISTINCT POSSIBILITY FROM LARAMIE COUNTY TO
SOUTHERN PLATTE AND GOSHEN COUNTIES...INTO THE SOUTHERN NEBRASKA
PANHANDLE. AGAIN CONFIDENCE IS INCREASING IN THE LIKELIHOOD OF THE
POSSIBILITY FOR LARGE HAIL...DAMAGING WINDS AND EVEN A TORNADO OR
TWO ACROSS THIS AREA TOMORROW AFTERNOON/EVENING.

ALONG WITH THE SEVERE POTENTIAL...TRAINING THUNDERSTORMS ALONG THE
LARAMIE RANGE AND VICINITY WITHIN DEEP MOIST UPSLOPE FLOW WILL
ENHANCE THE FLASH FLOOD THREAT ALONG THE LARAMIE RANGE...LARAMIE
VALLEY...AND NEARBY EASTERN PLAINS AS WELL. MODELS ARE IN FAIR
AGREEMENT WITH THIS PATTERN...SO ISSUED A FLASH FLOOD WATCH FOR THE
MORE FAVORABLE FLASH FLOOD POTENTIAL. WIDESPREAD 1 TO 2 INCHES WITH
LOCALLY HIGHER AMOUNTS ARE QUITE POSSIBLE LATE AFTERNOON THROUGH THE
EARLY OVERNIGHT PERIOD WHICH COULD CAUSE FLOODING PROBLEMS FOR SMALL
STREAMS AND RIVES...ANY BURN SCARS...STEEP TERRAIN...AND LOW LYING
AREAS.

.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 526 PM MDT FRI MAY 6 2016

THE OMEGA BLOCKING PATTERN THAT MUCH OF THE CONUS HAS SEEN OF LATE
WILL BEGIN BREAKING DOWN EARLY IN THE PERIOD AS THE NRN STREAM
BECOMES MORE ACTIVE. WILL HAVE TO DEAL WITH THIS PESKY UPPER LOW
WHICH WILL STILL BE SLOWLY PINWHEELING ACROSS THE INTERMOUNTAIN WEST
ON SUNDAY. CONTINUED PRECIPITATION AND COOL TEMPS CAN STILL BE
EXPECTED. THIS UPPER LOW FINALLY DEPARTS MONDAY AS IT PHASES WITH
THE ACTIVE NORTHWEST FLOW. THIS WILL REINFORCE THE COOL AIR MASS IN
PLACE THAT WILL PERSIST INTO THE FIRST HALF OF NEXT WEEK. SHOWERS
WILL STILL BE POSSIBLE MONDAY/TUESDAY...BUT COVERAGE WILL BE
SIGNIFICANTLY LESS THAN THIS WEEKEND. THE AIR MASS BEGINS TO DRY FOR
THE LATTER HALF OF NEXT WEEK AS THE NRN STREAM JET BEGINS TO SHIFT
OFF TO THE NORTHEAST. TEMPERATURES WILL LIKELY MODERATE AS
WELL...BACK TO MORE SEASONAL NORMS FOR THIS TIME OF YEAR.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SATURDAY EVENING)
ISSUED AT 529 PM MDT FRI MAY 6 2016

WYOMING TAFS...ISOLATED THUNDERSTORMS THIS EVENING PRODUCING
LOCALIZED MVFR...WITH AREAS OF IFR AND MVFR DEVELOPING LATE
TONIGHT. BECOMING MOSTLY VFR IN THE MORNING WITH SCATTERED SHOWERS
AND THUNDERSTORMS IN THE AFTERNOON PRODUCING LOCALIZED MVFR AND
WIND GUSTS TO 35 KNOTS.

NEBRASKA TAFS...VFR THIS EVENING...THEN BECOMING IFR AND MVFR
LATER TONIGHT WITH AREAS OF FOG. BECOMING VFR SATURDAY MORNING
WITH SCATTERED SHOWERS AND THUNDERSTORMS SATURDAY AFTERNOON
PRODUCING LOCALIZED MVFR AND WIND GUSTS TO 35 KNOTS.

&&

.FIRE WEATHER...
ISSUED AT 526 PM MDT FRI MAY 6 2016

A TREND TO COOLER AND WETTER CONDITIONS CAN BE EXPECTED THROUGH THE
WEEKEND AS A LOW PRESSURE SYSTEM MOVES IN FROM THE SOUTHWEST AND
THEN SLOWLY MOVES EAST ACROSS THE CENTRAL ROCKY MOUNTAIN REGION.
WETTING RAINS ARE LIKELY OVER MANY AREAS THIS AFTERNOON THROUGH
SATURDAY. SOME FLOODING IS POSSIBLE ACROSS THE AREA...PARTICULARLY
IN THE LARAMIE RANGE AND PLAINS OF SOUTHEAST WYOMING. SNOWS ARE
LIKELY OVER THE MOUNTAINS AS WELL SATURDAY NIGHT INTO SUNDAY.

&&

.CYS WATCHES/WARNINGS/ADVISORIES...
WY...FLASH FLOOD WATCH FROM SATURDAY AFTERNOON THROUGH LATE SATURDAY
     NIGHT FOR WYZ103-106>108-115>119.

NE...NONE.
&&

$$

SHORT TERM...RJM
LONG TERM...CAH
AVIATION...RUBIN
FIRE WEATHER...RJM



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