Flash Flood Watch 2, NWS Cheyenne, WY

064 
WGUS65 KCYS 140159
FFACYS

FLOOD WATCH
NATIONAL WEATHER SERVICE CHEYENNE WY
759 PM MDT MON JUN 13 2016

...FLASH FLOOD WATCH CANCELLED...

.THE THREAT FOR WIDESPREAD HEAVY RAIN HAS ENDED...SO THE FLASH
FLOOD WATCH HAS BEEN CANCELLED.

NEZ019-020-054-WYZ108-118-119-140300-
/O.CAN.KCYS.FF.A.0002.000000T0000Z-160614T0500Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
SCOTTS BLUFF-BANNER-KIMBALL-GOSHEN COUNTY-CENTRAL LARAMIE COUNTY-
EAST LARAMIE COUNTY-
INCLUDING THE CITIES OF...SCOTTSBLUFF...GERING...HARRISBURG...
KIMBALL...TORRINGTON...CHEYENNE...PINE BLUFFS
759 PM MDT MON JUN 13 2016

...FLASH FLOOD WATCH IS CANCELLED...

THE FLASH FLOOD WATCH FOR PORTIONS OF PANHANDLE NEBRASKA AND
SOUTHEAST WYOMING HAS BEEN CANCELLED. 

ALTHOUGH ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS WILL BE
POSSIBLE THIS EVENING...THE THREAT OF FLASH FLOODING HAS ENDED.

$$

RUBIN

Area Forecast Discussion
National Weather Service Cheyenne WY
356 AM MDT MON JUN 13 2016

.SHORT TERM...(Today through Wednesday)
Issued at 340 AM MDT Mon Jun 13 2016

Forecast for today and tonight appear on track with several
threats over the next 24 hours. Will be a rather busy day with
severe thunderstorms expected and the potential for flash
flooding. Enhanced risk for severe thunderstorms has been extended
northward to include the high plains of SE Wyoming east of a line
from Cheyenne to Douglas...and most of the western NE panhandle
this afternoon and into tonight. Instability and shear parameters
look good with models consistently showing 1500 to 2500 J/KG of
CAPE...30 to 45 KTS of 0-6 KM shear...and LI/s below -5c. In
addition...strong upper level divergence will be present as a
potent upper level trough currently over Nevada and srn California
moves east into Utah and Colorado. Model soundings indicate
impressive lapse rates between 0c and -20c heights where the
primary hail growth zone is located...so there is moderate
confidence that hail sizes may reach 2 to 3 inches in diameter in
a few locations. Large or very large hail will be the main threat
early...and then transition to a tornado and damaging straight
line wind threat as the afternoon progresses. EHI is now peaking
between 2 to 4 across portions of the panhandle late this
afternoon...so there is a threat of tornadoes east of the Laramie
Range and especially across the panhandle of Nebraska.

The other threat is FLASH FLOODING. There have been some
impressive rainfall totals last night and yesterday evening as a
slowly propagating MCS moved across the plains...mainly impacting
areas from Cheyenne to Torrington...and eventually eastward into
Kimball County and Scotts bluff County. There were numerous
reports of 1.5 to 3 inches of rainfall with even a few 4 inch
amounts. There were several reports of flash flooding and/or
street flooding in these areas as well. Contemplated issuing a
Flash Flood Watch for areas east of a line from Cheyenne to
Wheatland into the southern NE panhandle...but decided against it
early this morning after a few hours of analysis. The main problem
working against larger areas of flash flooding is the forecast
storm motion today and the potential for discrete supercells to
form. Current indications are storm motions may be as high as 30
to 35 MPH to the northeast or east...which will only result in
brief very heavy rainfall rates in addition to lots of hail due to
lower 0c and -20c levels. The other issue is the expected LLVL
wind direction which will mainly be out of the southeast and then
eventually veer into the south and southwest. Yesterday...LLVL
winds were out of the east up to 4000 feet AGL...which supported
slow east to northeast propagating lines of convection. Flash
flood threat appears to be higher further south and east with
a greater potential of south or southeast propagating squall
lines and bow echoes. Some flash flooding is still expected but
the area of impact and coverage is still uncertain. Will continue
to monitor this situation and will brief the day shift
accordingly...but the primary threat at this point appears to be
large hail...damaging winds...and isolated tornadoes.

For Tuesday and Wednesday...conditions are expected to improve
from west to east as the upper level trough moves overhead and
east of the forecast area by Tuesday afternoon. Can not rule out
an isolated thundershower across the eastern plains.
Otherwise...temperatures will begin to moderate as an upper level
ridge builds over the rockys and drier air moves into the forecast
area.

.LONG TERM...(Wednesday night through Sunday)
Issued at 230 AM MDT Mon Jun 13 2016

00Z medium range model guidance indicates that 1000-500mb heights
and thicknesses will be increasing throughout most of the forecast
period as a large upper high pressure ridge expands across the
central and southern Rockies and Great Plains. Large scale
subsidence and warm temperatures aloft will suppress convection,
even over the higher terrain. Above normal temperatures will
prevail with daytime highs Thursday through Saturday in the 70s
and 80s, with low to mid 90s east of the Laramie Range. A weak
frontal passage Sunday will lower high temperatures into the 80s
for the plains.

&&

.AVIATION...(For the 12Z TAFS through 12Z Tuesday morning)
Issued at 230 AM MDT Mon Jun 13 2016

Patchy MVFR visibilities and ceilings in fog and low clouds
will exist until 15Z this morning for most airfields east of
the Laramie Range. Scattered to numerous thunderstorms will
redevelop along and east of the Laramie Range this afternoon
and evening producing MVFR conditions in heavy rain...wind
gusts to 50 kt...hail and moderate to severe turbulence.

&&

.FIRE WEATHER...
Issued at 302 AM MDT Mon Jun 13 2016

NO FIRE WEATHER CONCERNS THIS WEEK DUE TO GREEN FUELS AND A HIGH
CHANCE FOR WETTING RAINS TODAY AND TONIGHT. NUMEROUS SHOWERS AND
THUNDERSTORMS EXPECTED OVER MUCH OF SOUTHEAST WYOMING AND WESTERN
NEBRASKA PANHANDLE THIS AFTERNOON THROUGH THIS EVENING AS A
DISTURBANCE MOVES ACROSS THE AREA. DRIER BUT COOL CONDITIONS
EXPECTED ON TUESDAY BEFORE TEMPERATURES BEGIN TO INCREASE BY
WEDNESDAY AND THURSDAY. RELATIVE HUMIDITIES ARE EXPECTED TO TREND
LOWER BY THE END OF THE WEEK...RANGING BETWEEN 15 TO 25 PERCENT
BY THURSDAY.

&&

.HYDROLOGY...

Issued at 230 AM MDT Mon Jun 13 2016

Heavy rainfall from thunderstorms Sunday evening produced short
term rises at Henry, Minatare, and Mitchell, Nebraska. This will
be the case again this afternoon and evening as the threat for
more heavy rainfall from thunderstorms exists. Much of the
mountain snow pack below 10000 feet has melted, with another one
to three feet remaining to melt. With cooler temperatures early
this week, snowmelt will be reduced, but increase somewhat later
this week with warmer temperatures. Therefore, minor flooding will
likely continue most of this week at Laramie and Saratoga, Wyoming.

&&

.CYS Watches/Warnings/Advisories...
WY...None.
NE...None.
&&

SHORT TERM...TJT
LONG TERM...MJ
AVIATION...MJ
FIRE WEATHER...TJT
HYDROLOGY...MJ

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE CHEYENNE WY
417 AM MDT MON JUN 13 2016

WYZ103>106-109>117-141030-
NORTH LARAMIE RANGE-FERRIS/SEMINOE/SHIRLEY MOUNTAINS-
SHIRLEY BASIN-CENTRAL LARAMIE RANGE AND SOUTHWEST 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-SOUTH LARAMIE RANGE FOOTHILLS-
417 AM MDT MON JUN 13 2016

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

.DAY ONE...TODAY AND TONIGHT

SCATTERED THUNDERSTORMS WILL DEVELOP BEGINNING LATE THIS MORNING...
AND CONTINUE THROUGH EARLY THIS EVENING. SOME OF THE STORMS MAY
BE STRONG WITH SMALL HAIL...BRIEF HEAVY RAIN AND WIND GUSTS TO 50
MPH.

.DAYS TWO THROUGH SEVEN...TUESDAY THROUGH SUNDAY

THE THREAT FOR WIDESPREAD HAZARDOUS WEATHER WILL BE LOW.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION WILL NOT BE REQUIRED TODAY OR TONIGHT.

NEZ002-003-019>021-054-055-095-096-WYZ101-102-107-108-118-119-
141030-
DAWES-BOX BUTTE-SCOTTS BLUFF-BANNER-MORRILL-KIMBALL-CHEYENNE-
NORTH SIOUX-SOUTH SIOUX-CONVERSE COUNTY LOWER ELEVATIONS-
NIOBRARA COUNTY-EAST PLATTE COUNTY-GOSHEN COUNTY-
CENTRAL LARAMIE COUNTY-EAST LARAMIE COUNTY-
417 AM MDT MON JUN 13 2016

THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF PANHANDLE
NEBRASKA...EAST CENTRAL WYOMING AND SOUTHEAST WYOMING.

.DAY ONE...TODAY AND TONIGHT

SCATTERED THUNDERSTORMS WILL DEVELOP ALONG THE LARAMIE RANGE
LATE THIS MORNING...AND BECOME MORE NUMEROUS THIS AFTERNOON
ACROSS THE HIGH PLAINS. SOME OF THE STORMS ALONG AND EAST OF
THE INTERSTATE 25 CORRIDOR WILL BECOME SEVERE AND PRODUCE VERY
LARGE HAIL...DAMAGING WINDS...VERY HEAVY RAIN THAT CAN CAUSE
FLASH FLOODING...AND ISOLATED TORNADOES. THE THREAT FOR SEVERE
THUNDERSTORMS WILL CONTINUE ACROSS THE WESTERN NEBRASKA PANHANDLE
UNTIL LATE THIS EVENING.

.DAYS TWO THROUGH SEVEN...TUESDAY THROUGH SUNDAY

ISOLATED THUNDERSTORMS WILL BE POSSIBLE ACROSS THE WESTERN
NEBRASKA PANHANDLE TUESDAY. OTHERWISE...THE THREAT FOR WIDESPREAD
HAZARDOUS WEATHER WILL BE LOW.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION WILL LIKELY BE REQUIRED THIS AFTERNOON AND
EVENING FOR AREAS ALONG AND EAST OF THE INTERSTATE 25 CORRIDOR.