Area Forecast Discussion
Issued by NWS Cheyenne, WY

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FXUS65 KCYS 301807
AFDCYS

Area Forecast Discussion
National Weather Service Cheyenne WY
1207 PM MDT MON MAY 30 2016

.SHORT TERM...(Today through Wednesday)
Issued at 300 AM MDT Mon May 30 2016

An active/unsettled weather pattern will continue through today as
an upper-level shortwave moves east across Montana. Farther south,
a closed upper low will drift slowly into western Arizona. Surface
cyclogenesis will take place this afternoon w/lee troughing across
southeast Wyoming by 18z. This feature is expected to advance east
into the western Nebraska panhandle this afternoon, yielding focus
for convective development. Severe threat should be low today with
the strongest mid-level flow well to the north, giving way to very
modest vertical shear with 500 mb flow generally under 25 knots. A
threat for strong storms will still exist though with dewpoints in
the 40s and 50s aiding in around 500 J/kg SBCAPE along/east of the
Laramie Range. Small hail and gusty winds can be expected, but not
looking at an organized threat for severe weather. Temps today are
expected to be similar to Sunday, with 70s over the high plains of
southeast Wyoming and 80s over parts of the Panhandle. Showers and
thunderstorms should gradually diminish overnight with the loss of
diurnal instability, but there should be enough dynamic support to
keep at least isolated activity through early Tuesday. Much cooler
for Tuesday in the post-frontal air mass with 700 mb temps between
0-3 deg C. A few thunderstorms will be possible once again as mid-
level cyclonic flow remains intact, but they should be confined to
the higher terrain for the most part. The aforementioned shortwave
will move into the upper midwest on Wednesday, allowing a building
ridge over the CWA w/increasing deep subsidence as well as warming
thermal profiles. As such, convective potential should continue to
decrease.

.LONG TERM...(Wednesday night through Sunday)
Issued at 300 AM MDT Mon May 30 2016

Warmer and drier conditions as high pressure builds into the area.
700mb temperatures really begin to warm and by Friday are
approaching +12C. Should be seeing mid 80s in the Panhandle and
did go a little higher on temperatures than guidance suggests.

&&

.AVIATION...(For the 18Z TAFS through 18Z Tuesday afternoon)
Issued at 1156 AM MDT Mon May 30 2016

Latest water vapor loop was showing a very distinguished shortwave
anomaly moving through the central wyoming. This feature appears
to be the trigger for the convection that developed during the
last hour. Latest radar loop was showing a thunderstorm moving
south of Cheyenne with some reports of pea size hail. This
thunderstorm will continue to shift east during the afternoon and
will most likely continue its journey into the southern Nebraska
Panhandle. Other scattered storms are possible this afternoon with
the bulk of these storms shifting east into the panhandle. After
this shortwave moves through the flow is expected to turn north
which may cause some lower ceilings to develop towards daybreak.
However, at this point ceilings should generally remain above
MVFR. &&

.FIRE WEATHER...
Issued at 203 AM MDT Mon May 30 2016

Minimal fire weather concerns over the next several days with non-
critical fuels and humidities/winds generally remaining outside of
critical thresholds. A cold front will move across the area Monday
night, keeping temperatures mild through Tuesday. A warming/drying
trend will commence on Wednesday, and continue through the rest of
the week.

&&

.HYDROLOGY...
Issued at 241 PM MDT Sun May 29 2016

The North Platte and Laramie Rivers will continue to run high,
but remain steady or slowly recede over the next couple of days.
The exception will be areas that receive moderate rainfall today
which could produce short-term rises in river levels. Warmer
temperatures mid to late week will increase snowmelt once again.
Therefore, expect rises on area rivers, creeks and streams by next
weekend.

&&

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

$$

SHORT TERM...CLH
LONG TERM...GCC
AVIATION...REC
FIRE WEATHER...CLH
HYDROLOGY...RJM/CLH


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