Special Weather Statement, NWS Cheyenne, WY

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
421 PM MDT WED MAY 7 2014

.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 400 PM MDT WED MAY 7 2014

WATER VAPOR IMAGERY SHOWED CLOSED UPPER LOW SPINNING JUST SOUTH OF
SLC. DIFFLUENCE ALOFT AND ENERGY LIFTING NORTHEAST ACROSS CO AND
WY PROVIDING SUBSTANTIAL LIFT FOR CLUSTERS OF INTENSE CONVECTION
FROM SOUTHEAST WY INTO NORTHERN CO. BULK SHEAR PARAMETERS OF 50-60
KT AND SBCAPES OF 1500-2000 J/KG ADEQUATE FOR LARGE HAIL AND EVEN
A FEW TORNADOES...ESPECIALLY ALONG A SURFACE BOUNDARY DRAPED NEAR
THE CO-WY BORDER. THE FOCUS FOR THE CONVECTION WILL SHIFT EAST AND
SOUTH THIS EVENING AS THE UPPER AND SURFACE LOW CENTERS MOVE FROM
THE CENTRAL ROCKIES INTO NEBRASKA TONIGHT. LOCALLY HEAVY RAINFALL
OVER ALREADY SATURATED GROUNDS FROM EAST LARAMIE COUNTY INTO THE
SOUTHERN NE PANHANDLE WILL MAINTAIN A FLASH FLOOD THREAT THROUGH
TONIGHT.

AFTER THE SEVERE THREAT ENDS...THE NEXT CONCERN WILL BE ACCUMULATING
SNOW LATER TONIGHT AND THURSDAY MORNING AS THE COLDER AIR INFILTRATES
INTO THE CWA WITH THE PASSAGE OF THE UPPER TROUGH. GFS QG PROGS DEPICT
THE STRONGEST UPWARD VERTICAL MOTION LIFTING NORTHEAST ACROSS EASTERN
WY PLAINS AND NEBRASKA PANHANDLE BETWEEN 06Z AND 12Z THURSDAY. SHOWERS
WILL CHANGE TO SNOW BETWEEN 3 AM AND 6 AM AS TEMPERATURES FALL TO
INTO THE LOWER AND MID 30S. POTENTIAL IS THERE FOR HEAVY WET SNOWFALL
FROM EXTREME EAST CENTRAL WY INTO THE NORTHERN NE PANHANDLE EARLY
THURSDAY MORNING BEFORE TAPERING OFF. GENERALLY LOOKING AT 3 TO 6
INCHES...HIGHEST ALONG THE PINE RIDGE. OVER THE MOUNTAINS...2 TO 4
INCHES WITH HIGHER AMOUNTS ABOVE 8000 FT...WITH 1 TO 2 INCHES OVER
THE SOUTHEAST WY PLAINS INCLUDING CHEYENNE. ISSUED A WINTER WEATHER
ADVISORY FOR NIOBRARA...SIOUX...DAWES AND BOX BUTTE COUNTIES FROM
3 AM THROUGH 11 AM THURSDAY. IT WILL BE BRISK ACROSS THE PLAINS
WITH NORTHWEST WINDS 15 TO 25 MPG AND GUSTY.

THE SNOW CHANGES TO RAIN BY THURSDAY AFTERNOON AS TEMPERATURES RISE
INTO THE UPPER 30S AND LOWER 40S. FAVORED THE COOLER METMOS FOR
HIGH TEMPERATURES WITH LOWER THICKNESSES AND 700MB TEMPERATURES
AROUND -5C. THE SHOWERS END THURSDAY EVENING WITH THE PASSAGE OF A
SHORTWAVE RIDGE...BUT RETURNS TO MOST OF SOUTH CENTRAL AND SOUTHEAST
WY FRIDAY AFTERNOON WITH THE APPROACH OF THE NEXT PACIFIC TROUGH.
COULD SEE ISOLATED TSTORMS WEST OF THE LARAMIE RANGE. FRIDAY WILL
BE MUCH WARMER WITH 700MB TEMPERATURES NEAR 0C. IT WILL BECOME
BREEZY IN THE AFTERNOON AS WEST-SOUTHWEST WINDS INCREASE TO 25 TO
35 MPH ALONG AND WEST OF THE LARAMIE RANGE.

.LONG TERM...(FRIDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 315 PM MDT WED MAY 7 2014

SHOWER ACTIVITY WILL DECREASE FRIDAY EVENING WITH PASSAGE OF UPPER
IMPULSE LEAVING A MILD AND MAINLY DRY PATTERN OVER THE CWA SATURDAY.
MEANWHILE NEXT UPPER LOW DROP SE OVER THE WESTERN PART OF THE COUNTRY
WITH A SWLY UPPER FLOW OVER THE CWA AHEAD OF IT. NEXT PUSH OF COOLER
AIR DROPS OUT OF CANADA ACROSS THE AREA AS WELL SETTING UP ANOTHER
WET PATTERN SATURDAY NIGHT THROUGH SUNDAY NIGHT. RAIN WILL BE LIKELY
OVER THE CWA WITH SOME SNOW AS WELL OVER HIGHER ELEVATIONS. HAVE
UNDERCUT GUIDANCE TEMPS FOR SUNDAY GIVEN THE EXPECTED CLOUDS...PCPN
AND LOW THICKNESSES. CLEARING OUT MONDAY WITH THE PASSAGE OF THE UPPER
TROUGH AXIS WITH WARMING TEMPS THRU WEDS. A FAST MOVING SHORTWAVE MAY
BRING A FEW SHOWERS TO NORTHERN PARTS OF THE CWA TUESDAY NIGHT.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z THURSDAY EVENING)
ISSUED AT 315 PM MDT WED MAY 7 2014

SCTD TO NUMEROUS SHOWERS AND TSTRMS WILL MOVE OVER THE MTNS AND EASTERN
PLAINS INTO EARLY THIS EVENING WITH ASSOCIATED MVFR/IFR CIGS AND VSBYS.
WIDESPREAD MVFR/IFR CONDITIONS DEVELOPING THIS EVENING AS UPSLOPE FLOW
INCREASES WITH RAIN AND SNOW INCREASING AS WELL...CONTINUING INTO
THURSDAY MORNING.

&&

.FIRE WEATHER...
ISSUED AT 242 PM MDT WED MAY 7 2014

A POTENT SPRING STORM SYSTEM WILL BRING A WIDE VARIETY OF WEATHER TO
THE DISTRICTS TONIGHT AND THURSDAY...WITH THUNDERSTORMS OVER PARTS
OF THE PLAINS THIS EVENING...THEN RAIN AND SNOW LATE TONIGHT AND
THURSDAY. COOL TO MILD TEMPERATURES WILL SETTLE ACROSS THE AREA
INTO THE WEEKEND WITH MAINLY DRY WEATHER THEN THE NEXT LOW PRESSURE
SYSTEM TO AFFECT THE AREA WILL ARRIVE BY SUNDAY BRINGING MORE RAIN
AND SNOW TO MUCH OF THE AREA.

&&

.CYS WATCHES/WARNINGS/ADVISORIES...
WY...WINTER WEATHER ADVISORY FROM 3 AM TO 11 AM MDT THURSDAY FOR
     WYZ102.

     FLASH FLOOD WATCH THROUGH LATE TONIGHT FOR WYZ119.

     FLOOD WATCH FROM THURSDAY EVENING THROUGH LATE SATURDAY NIGHT
     FOR WYZ115.

NE...WINTER WEATHER ADVISORY FROM 3 AM TO 11 AM MDT THURSDAY FOR
     NEZ002-003-095-096.

     FLASH FLOOD WATCH THROUGH LATE TONIGHT FOR NEZ020-021-054-055.

&&

SHORT TERM...JAMSKI
LONG TERM...RE
AVIATION...RE
FIRE WEATHER...JAMSKI

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE CHEYENNE WY
442 PM MDT WED MAY 7 2014

WYZ101>107-109>116-082245-
CONVERSE COUNTY LOWER ELEVATIONS-NIOBRARA COUNTY-
NORTH LARAMIE RANGE-FERRIS/SEMINOE/SHIRLEY MOUNTAINS-
SHIRLEY BASIN-CENTRAL LARAMIE RANGE AND SOUTHWEST PLATTE COUNTY-
EAST PLATTE COUNTY-CENTRAL CARBON COUNTY-
NORTH SNOWY RANGE FOOTHILLS-SOUTHWEST CARBON COUNTY-
SIERRA MADRE RANGE-UPPER NORTH PLATTE RIVER BASIN-SNOWY RANGE-
LARAMIE VALLEY-SOUTH LARAMIE RANGE-
442 PM MDT WED MAY 7 2014

THIS HAZARDOUS WEATHER OUTLOOK IS FOR EAST CENTRAL WYOMING...
SOUTH CENTRAL WYOMING AND SOUTHEAST WYOMING.

.DAY ONE...TONIGHT

SHOWERS AND ISOLATED THUNDERSTORMS WILL PERSIST OVER PORTIONS
OF SOUTH CENTRAL AND SOUTHEAST WYOMING THIS EVENING. BRIEF HEAVY
RAIN...SMALL HAIL AND GUSTY WINDS WILL BE POSSIBLE WITH SOME OF
THE THUNDERSTORMS.

AS POTENT LOW PRESSURE SYSTEM MOVES OUT OF THE CENTRAL ROCKIES
AND INTO NEBRASKA TONIGHT...ACCUMULATING SNOW IS LIKELY LATER
TONIGHT AND THURSDAY MORNING. AT THIS TIME...ACCUMULATIONS WILL
RANGE FROM 2 TO 6 INCHES OVER THE MOUNTAINS...WITH 1 TO 2 INCHES
FOR THE PLAINS.

.DAYS TWO THROUGH SEVEN...THURSDAY THROUGH TUESDAY

THE SNOW WILL MIX WITH OR CHANGE TO RAIN THURSDAY AFTERNOON.
ANOTHER PACIFIC TROUGH WILL BRING SCATTERED SHOWERS AND ISOLATED
THUNDERSTORMS FRIDAY AFTERNOON AND EVENING.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION WILL NOT BE NEEDED TONIGHT.

&&

THIS PRODUCT...ALONG WITH OTHER WEATHER...HYDROLOGIC...AND
CLIMATE INFORMATION IS AVAILABLE ON THE WEB AT...
HTTP://WEATHER.GOV/CHEYENNE

NEZ002-003-019>021-054-055-095-096-WYZ108-117>119-082245-
DAWES-BOX BUTTE-SCOTTS BLUFF-BANNER-MORRILL-KIMBALL-CHEYENNE-
NORTH SIOUX-SOUTH SIOUX-GOSHEN COUNTY-
SOUTH LARAMIE RANGE FOOTHILLS-CENTRAL LARAMIE COUNTY-
EAST LARAMIE COUNTY-
442 PM MDT WED MAY 7 2014

THIS HAZARDOUS WEATHER OUTLOOK IS FOR THE WESTERN NEBRASKA
PANHANDLE...SOUTHEAST WYOMING.

.DAY ONE...TONIGHT

NUMEROUS SHOWERS AND SCATTERED THUNDERSTORMS DEVELOPING LATE
THIS AFTERNOON WILL CONTINUE THIS EVENING. SOME OF THE STORMS
WILL BE SEVERE EARLY THIS EVENING WITH LARGE HAIL TO TWO INCHES
IN DIAMETER...DAMAGING WINDS TO 60 MPH...AND POSSIBLY A FEW
TORNADOES. TORRENTIAL RAIN FALLING OVER ALREADY SATURATED
GROUNDS IN EXTREME SOUTHEAST WYOMING AND SOUTHERN NEBRASKA
PANHANDLE WILL INCREASE THE THREAT FOR FLASH FLOODING.

LATER TONIGHT...THE SHOWERS WILL CHANGE OVER TO WET SNOW AS
COLDER AIR OVERSPREADS THE AREA WITH THE PASSAGE OF THE UPPER
LEVEL TROUGH. THE SNOW WILL BE HEAVY OVER THE NORTHERN NEBRASKA
PANHANDLE INCLUDING THE PINE RIDGE WHERE AS MUCH AS SIX INCHES
IS LIKELY.

.DAYS TWO THROUGH SEVEN...THURSDAY THROUGH TUESDAY

THE SNOW WILL MIX WITH OR CHANGE TO RAIN THURSDAY AFTERNOON.

A MORE POTENT STORM SYSTEM WILL PRODUCE WIDESPREAD RAIN AND SNOW
SATURDAY NIGHT AND SUNDAY. ACCUMULATING SNOW APPEARS LIKELY FOR
ELEVATIONS ABOVE 5000 FEET.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION IS LIKELY THIS AFTERNOON AND EARLY THIS EVENING
FOR EXTREME SOUTHEAST WYOMING AND THE SOUTHERN NEBRASKA PANHANDLE.

&&

THIS PRODUCT...ALONG WITH OTHER WEATHER...HYDROLOGIC...AND
CLIMATE INFORMATION IS AVAILABLE ON THE WEB AT...
HTTP://WEATHER.GOV/CHEYENNE

JAMSKI

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE CHEYENNE WY
443 PM MDT WED MAY 07 2014

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0442 PM     HAIL             3 N MORRILL             42.01N 103.92W
05/07/2014  E0.25 INCH       SIOUX              NE   TRAINED SPOTTER

            HAIL COVERS THE ROAD

&&

BCHAPMAN

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE CHEYENNE WY
451 PM MDT WED MAY 7 2014

NEZ020-072330-
BANNER NE-
451 PM MDT WED MAY 7 2014

...SIGNIFICANT WEATHER ADVISORY FOR CENTRAL BANNER COUNTY UNTIL 530
PM MDT...

AT 445 PM MDT...NATIONAL WEATHER SERVICE DOPPLER RADAR WAS TRACKING
STRONG THUNDERSTORMS ALONG A LINE EXTENDING THROUGH CENTRAL BANNER
COUNTY. THESE STORMS WERE MOVING NORTH AT 25 MPH.

VERY HEAVY RAIN AND HAIL UP TO ONE HALF INCH IN DIAMETER ARE
EXPECTED WITH THESE STORMS.

LOCATIONS NEAR THE PATH OF THIS STORM INCLUDE...
  HARRISBURG...
  THE INTERSECTION OF HIGHWAY 88 AND WRIGHTS GAP ROAD...

IF THREATENING WEATHER APPROACHES YOUR AREA...TAKE SHELTER IN A
STURDY BUILDING.

TORRENTIAL RAIN...WHICH MAY FLOOD LOW LYING AREAS SUCH AS DITCHES AND
UNDERPASSES...IS ALSO LIKELY. DO NOT DRIVE YOUR VEHICLE ON A FLOODED
ROADWAY.

&&

LAT...LON 4170 10379 4170 10348 4140 10350 4140 10386
TIME...MOT...LOC 2249Z 189DEG 21KT 4152 10373

HAMMER

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE CHEYENNE WY
453 PM MDT WED MAY 07 2014

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0450 PM     HAIL             BUSHNELL                41.23N 103.89W
05/07/2014  E1.00 INCH       KIMBALL            NE   TRAINED SPOTTER

0448 PM     HAIL             3 W BUSHNELL            41.23N 103.95W
05/07/2014  E0.25 INCH       KIMBALL            NE   TRAINED SPOTTER

            SEEMED TO BE SOFT BUT LOTS OF IT

&&

BCHAPMAN

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