Special Weather Statement, NWS Cheyenne, WY

Area Forecast Discussion
National Weather Service Cheyenne WY
1122 AM MDT FRI JUL 22 2016

.SHORT TERM...(Today thru Sunday)
Issued at 249 AM MDT Fri Jul 22 2016

Today-Tonight:
Latest water vapor loop was showing the tropical plume across
southeast Wyoming. This plume of moisture has produced some thick
cloud cover overnight which has really kept up temperatures.
Latest IR loop was showing these clouds finally starting to lift
northeast which should allow for temperatures to dip towards
daybreak. Water vapor loop was also showing a potential vorticity
anomaly moving through western Wyoming. This feature is progged to
skirt east through central Wyoming this afternoon and help trigger
convection along the Laramie Range this afternoon. Instability
will be somewhat limited with surface based capes generally
ranging from 800-1200 j/kg based on the NAM/RAP soundings and
effective shear values around 25kts. Best instability appears to
be in the panhandle so I Would not be surprised to see a few
strong storms this afternoon with the storm motion generally
northeast at 10 to 15kts. HRRR/Local WRF solutions are showing a
fairly organized cluster of storms pushing through areas east of
the Laramie Range this afternoon with the best coverage mainly
east of a Cheyenne to Wheatland line. This cluster of convection
should push east of the area shortly after 9 pm, and should bring
about clearing skies afterwards.

Saturday-Sunday:
Saturday should be a fairly quiet day as the upper level trof
along the U.S./Canadian border skirts east and drags a frontal
boundary through areas east of the Laramie Range on Saturday
morning. This should tend to dry us out for a short while with
slightly cooler temperatures. The models are trying to hint at
some convection developing along the CO/WY border during the
evening due to the return flow setting up. Went ahead and
introduced pops near Cheyenne Saturday evening, but confidence is
still rather low. Another weak shortwave in Montana is expected to
move through Northern Wyoming on Sunday which may help trigger
some convection east of the Laramie Range. This wave appears to
subtle according to various models solutions, but we will have to
see how this pans out before making large adjustments to precip.
chances.

.LONG TERM...(Sunday night through Thursday)
Issued at 249 AM MDT Fri Jul 22 2016

Subtropical ridge center will be located over Colorado for Monday
with heights aloft rising through the day.  The GFS shows more
convection breaking out across the plains during the aftn/evening
than the ECMWF, with better llvl moisture and instability.  Kept
tstms mostly isolated with the ridging aloft.  The midlvl ridge
center will shift westward toward Utah and the Great Basin by
Wed/Thurs.  It appears that convective chances could increase
especially to the east of the Laramie Range by the middle of next
week as weak shortwaves in northwesterly flow aloft move overhead.
Bulk shear in this pattern is decent (30-40 kts) as are CAPE values,
thus can not rule a strong or svr storm.  Temps through the extended
are expected to be around seasonal norms.

&&

.AVIATION...(For the 18Z TAFS through 18Z Saturday afternoon)
Issued at 1117 AM MDT Fri Jul 22 2016

VFR. Isolated to scattered showers and thunderstorms will develop
over southeast Wyoming this afternoon and move northeast into the
Nebraska Panhandle by this evening. Winds will be southwesterly
10-20 kt. Brief MVFR visibility in moderate to heavy rainfall and
gusty/erratic winds will be possible with some of the thunderstorms.
The convection will end later this evening, with winds becoming
westerly 5-10 kt late tonight.

&&

.FIRE WEATHER...
Issued at 249 AM MDT Fri Jul 22 2016

No major concerns for fire weather today due to better recovery of
the relative humidities and limited wind speeds. The only factor
could be the potential for thunderstorms this afternoon which may
produce some lightning on dry fuels in the Wyoming and Nebraska
Plains. Critical Fire weather conditions will be more favorable
over areas west of the Laramie Range on Saturday due to stronger
winds near 25 to 30 mph and low relative humidity values. However,
most of the fuels are not favorable for rapid fire growth.

&&

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

SHORT TERM...REC
LONG TERM...ZF
AVIATION...MAJ
FIRE WEATHER...REC

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE CHEYENNE WY
1132 AM MDT FRI JUL 22 2016

WYZ101>119-231745-
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-GOSHEN 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-
CENTRAL LARAMIE COUNTY-EAST LARAMIE COUNTY-
1132 AM MDT FRI JUL 22 2016

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

.DAY ONE...THIS AFTERNOON AND TONIGHT

WIDELY SCATTERED SHOWERS AND THUNDERSTORMS WILL DEVELOP THIS
AFTERNOON AND CONTINUE THROUGH EARLY EVENING. THE SEVERE STORM
THREAT WILL BE LOW...HOWEVER THE STRONGER STORMS COULD PRODUCE
BRIEF MODERATE TO HEAVY RAINFALL AND GUSTY WINDS...MAINLY EAST
OF THE LARAMIE RANGE.

.DAYS TWO THROUGH SEVEN...SATURDAY THROUGH THURSDAY

ISOLATED AFTERNOON AND EVENING THUNDERSTORMS WILL DEVELOP
MONDAY THROUGH THURSDAY. SEVERE WEATHER IS NOT EXPECTED.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION WILL NOT BE REQUIRED.

NEZ002-003-019>021-054-055-095-096-231745-
DAWES-BOX BUTTE-SCOTTS BLUFF-BANNER-MORRILL-KIMBALL-CHEYENNE-
NORTH SIOUX-SOUTH SIOUX-
1132 AM MDT FRI JUL 22 2016

THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF WESTERN
NEBRASKA.

.DAY ONE...THIS AFTERNOON AND TONIGHT

WIDELY SCATTERED SHOWERS AND THUNDERSTORMS WILL DEVELOP LATE
THIS AFTERNOON AND CONTINUE THROUGH LATE EVENING. THE SEVERE
STORM THREAT WILL BE LOW...HOWEVER THE STRONGER STORMS COULD
PRODUCE BRIEF MODERATE TO HEAVY RAINFALL AND GUSTY WINDS.

.DAYS TWO THROUGH SEVEN...SATURDAY THROUGH THURSDAY

ISOLATED AFTERNOON AND EVENING THUNDERSTORMS WILL DEVELOP
MONDAY THROUGH THURSDAY. SEVERE WEATHER IS NOT EXPECTED.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION WILL NOT BE REQUIRED.

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE CHEYENNE WY
116 PM MDT FRI JUL 22 2016

WYZ102-222000-
NIOBRARA COUNTY WY-
116 PM MDT FRI JUL 22 2016

...SIGNIFICANT WEATHER ADVISORY FOR NORTHEASTERN NIOBRARA COUNTY
UNTIL 200 PM MDT...

AT 115 PM MDT...DOPPLER RADAR WAS TRACKING A STRONG THUNDERSTORM 12
MILES SOUTH OF REDBIRD...OR 21 MILES NORTH OF LUSK...MOVING NORTHEAST
AT 15 MPH.

HALF INCH HAIL AND WINDS IN EXCESS OF 40 MPH WILL BE POSSIBLE WITH
THIS STORM.

LOCATIONS IMPACTED INCLUDE...
REDBIRD.

LAT...LON 4319 10405 4316 10405 4298 10423 4301 10442
      4331 10428
TIME...MOT...LOC 1915Z 217DEG 14KT 4305 10429

RE

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE CHEYENNE WY
137 PM MDT FRI JUL 22 2016

NEZ002-222015-
DAWES NE-
137 PM MDT FRI JUL 22 2016

...SIGNIFICANT WEATHER ADVISORY FOR SOUTHWESTERN DAWES COUNTY UNTIL
215 PM MDT...

AT 136 PM MDT...DOPPLER RADAR WAS TRACKING A STRONG THUNDERSTORM 11
MILES SOUTH OF CRAWFORD...OR 30 MILES SOUTHWEST OF CHADRON...MOVING
NORTHEAST AT 15 MPH.

DIME SIZE HAIL WILL BE POSSIBLE WITH THIS STORM.

THIS STORM WILL REMAIN OVER MAINLY RURAL AREAS OF SOUTHWESTERN DAWES
COUNTY.

LAT...LON 4245 10338 4251 10348 4268 10345 4264 10317
TIME...MOT...LOC 1936Z 212DEG 13KT 4252 10342

RE

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE CHEYENNE WY
207 PM MDT FRI JUL 22 2016

NEZ002-095-222045-
NORTH SIOUX NE-DAWES NE-
207 PM MDT FRI JUL 22 2016

...SIGNIFICANT WEATHER ADVISORY FOR NORTHEASTERN SIOUX AND DAWES
COUNTIES UNTIL 245 PM MDT...

AT 207 PM MDT...DOPPLER RADAR WAS TRACKING A LINE OF STRONG
THUNDERSTORMS ALONG A LINE EXTENDING FROM NEAR MONTROSE TO NEAR
CRAWFORD TO 7 MILES NORTHWEST OF BOX BUTTE CAMPGROUND...AND MOVING
NORTHEAST AT 20 MPH.

DIME SIZE HAIL AND WIND GUSTS UP TO 50 MPH WILL BE POSSIBLE WITH
THESE STORMS.

LOCATIONS IMPACTED INCLUDE...
CHADRON...CRAWFORD...WHITNEY LAKE...RED CLOUD CAMPGROUND...CHADRON
AIRPORT...FORT ROBINSON CAMPGROUND...CHADRON CAMPGROUND...MONTROSE...
WHITNEY...CHADRON ST PARK AND FORT ROBINSON.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

TO REPORT SEVERE WEATHER...CONTACT YOUR NEAREST LAW ENFORCEMENT
AGENCY. THEY WILL RELAY YOUR REPORT TO THE NATIONAL WEATHER SERVICE
OFFICE IN CHEYENNE.

&&

LAT...LON 4246 10334 4296 10381 4300 10375 4300 10293
      4254 10278
TIME...MOT...LOC 2007Z 236DEG 19KT 4295 10368 4273 10336 4250 10324

HAMMER

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE CHEYENNE WY
212 PM MDT FRI JUL 22 2016

NEZ019-021-222100-
MORRILL NE-SCOTTS BLUFF NE-
212 PM MDT FRI JUL 22 2016

...SIGNIFICANT WEATHER ADVISORY FOR NORTHWESTERN MORRILL AND
NORTHEASTERN SCOTTS BLUFF COUNTIES UNTIL 300 PM MDT...

AT 212 PM MDT...DOPPLER RADAR WAS TRACKING A STRONG THUNDERSTORM NEAR
MINATARE...OR 11 MILES EAST OF SCOTTSBLUFF...MOVING NORTHEAST AT 10
MPH.

HALF INCH HAIL AND WIND GUSTS UP TO 50 MPH WILL BE POSSIBLE WITH THIS
STORM.

LOCATIONS IMPACTED INCLUDE...
MINATARE...MOOMAWS CORNER...LAKE MINATARE...
LAKE MINATARE CAMPGROUND AND MCGREW.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

TO REPORT SEVERE WEATHER...CONTACT YOUR NEAREST LAW ENFORCEMENT
AGENCY. THEY WILL RELAY YOUR REPORT TO THE NATIONAL WEATHER SERVICE
OFFICE IN CHEYENNE.

&&

LAT...LON 4174 10346 4187 10359 4200 10359 4200 10319
      4182 10321
TIME...MOT...LOC 2012Z 229DEG 7KT 4186 10345

HAMMER