Area Forecast Discussion
Issued by NWS Cheyenne, WY

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FXUS65 KCYS 230451
AFDCYS

Area Forecast Discussion
National Weather Service Cheyenne WY
1051 PM MDT WED JUN 22 2016

.SHORT TERM...(This evening through Friday night)
Issued at 300 PM MDT Wed Jun 22 2016

Pretty quiet weather today and tonight across Wyoming and western
Nebraska with warm temperatures and only a marginal chance for
thunderstorms near the Colorado border. Surface frontal boundary
has pushed westward and is currently across central Carbon county
extending southeast towards southern Albany county. This area will
likely be the only focus for showers and thunderstorm activity
late this afternoon and this evening...so kept low POP around 20
percent across the mountains and areas south of the I80 corridor.
This boundary will begin to move eastward by early Thursday
morning as winds shift into the southwest...so there may be some
shower activity along the I25 corridor by daybreak.
Otherwise...quiet weather conditions should persist through
Thursday morning.

The primary concern in the short range forecast will be on
Thursday as the frontal boundary will move east into the high
plains. This feature...along with the timing...will be the main
forcing mechanism Thursday afternoon/evening to trigger strong
thunderstorms. The most favorable location for strong storms will
be southeast of a line from Cheyenne to Torrington. Can not rule
out a few severe thunderstorms will large hail...heavy
rainfall...and strong winds as well with models showing 0-6km
shear around 40 to 45 knots across the southern panhandle of
Nebraska along with LI/s below -5c and CAPE values between 1500 to
2000 j/kg. High temperatures for Thursday will be a tricky
in these areas since it may cloud up pretty early...but still
expect high temperatures in the 80`s to low/mid 90`s across the
Nebraska panhandle. Depending on the amount or coverage of
precipitation late on Thursday...may need to add low clouds and
patchy fog along and east of Interstate 25 as well. Friday will
be similar with a lower chance of strong thunderstorms due to the
lack of shear...but temperatures will likely be a few degrees
higher in the afternoon. A strong cold front for this time of the
year will then push through Wyoming and Nebraska Friday
night...resulting in cooler temperatures and drier conditions.

.LONG TERM...(Saturday through Tuesday)
Issued at 300 PM MDT Wed Jun 22 2016

Fropa is still fcsted to occur Saturday morning associated with the
upper trough moving across eastern Mountain and the Dakotas.  It
will be around 10 degrees cooler and also breezy, with soundings
showing 25-30 kts at the top of the mixed layer.  Despite the cooler
airmass, min rh values will still drop to 10-20 percent, so may have
to consider a fire weather headlines at some point for the zones
where fuels are ready.  No tstms are expected through Sunday with
CAPE near zero.  With a sfc high building into the northern plains
by Monday, good llvl moisture will be transported into the Nebraska
Panhandle.  Could see isolated convection develop by the
aftn/evening in the Panhandle.  More widespread tstms will be
possible over the plains by Tuesday as a shortwave moves overhead in
the northwesterly flow aloft.  Both the GFS/ECMWF show good bulk
shear (40-50 kts), along with CAPE values 1500-2500 j/kg by early
next week. Thus, would not be surprised to see some strong or severe
storms.

&&

.AVIATION...(For the 06Z TAFS through 06Z Thursday night)
Issued at 1049 PM MDT Wed Jun 22 2016

VFR conditions through the overnight hours. Better chances for
thunderstorms Thursday afternoon for our Nebraska Panhandle
airports and around the Laramie Range. VCTS wording in TAFs as its
still a little too far out for predominant conditions.

&&

.FIRE WEATHER...
Issued at 209 PM MDT Wed Jun 22 2016

Low fire weather concerns over the next 36 hours based on forecast
humidities and winds...but then elevated concerns for east central
Wyoming on Friday as west to southwest winds increase during the
afternoon with daytime humidities around 15 percent. Cooler
temperatures and higher humidities are expected for later this
weekend and early next week after a cold front moves across the
area late Friday night.

&&

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

$$

SHORT TERM...TJT
LONG TERM...ZF
AVIATION...GCC
FIRE WEATHER...TJT



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