Area Forecast Discussion
Issued by NWS Cheyenne, WY

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FXUS65 KCYS 192315
AFDCYS

Area Forecast Discussion
National Weather Service Cheyenne WY
515 PM MDT Wed Jul 19 2017

.SHORT TERM...(This evening through Friday)
Issued at 306 PM MDT Wed Jul 19 2017

It is quite the scorcher out there today with many locations in the
90s and even 100s. Increasing cloud cover should help to curb
additional heating. Already, a few showers and thunderstorms have
developed out west and across our northern counties, and anticipate
this trend to continue through the evening. The main cold front
looks to be hung up along our northern counties, while a prefrontal
trough/dryline has moved east across the southeast Wyoming counties.
Winds in the wake of this trough have become more of a
north/northeast direction likely a result of some terrain forcing as
well. This should aide enhancement of current convective
development through the evening. Although llvls are quite dry
across southeast Wyoming, plentiful moisture aloft should help
produce light to moderate rain from this activity and not solely
virga. Warm temps aloft still may curtail thunderstorm intensity,
but enough forcing and moisture should redevelop at least garden
variety t- storms through the late afternoon and evening. The cold
front looks to push south and weaken overnight, but still may
initiate a few showers through the early morning hours.

East-southeasterly return flow in the wake of the front looks to
advect higher llvl moisture across our plains, with a patchy
stratus deck likely to develop tonight. Temperatures for tomorrow
will also be a bit cooler, but readings will still be hot.
Forecast soundings illustrate a moderately unstable environment
with a weak cap in place, so would imagine convection will develop
over the higher terrain by mid afternoon, and shift east across
the forecast area through the evening. Midlevel/upper level flow
is not strong by any means, but bulk shear values around 30 kts
could contribute to the development of a strong storm or two with
small hail and gusty winds. Moderate rainfall is a good bet as
well from this activity, but with dry antecedent conditions,
flooding potential will remain localized. Another front moving
through the forecast area on Friday will focus convection more
over western and southern locations.

.LONG TERM...(Friday night through Tuesday)
Issued at 306 PM MDT Wed Jul 19 2017

A drier airmass will push into the region by late Friday into
Saturday as the midlvl ridge shifts westward into Utah and
northwesterly flow aloft ensues.  The best coverage of storms on
Saturday aftn will likely be south into Colorado.  The ridge axis
should be overhead on Sunday with convection limited by the
subsidence aloft.  Tstm chances may be on the increase by early next
week as the ridge continues to move eastward and midlvl flow becomes
more southwesterly, transporting monsoonal moisture into the region.
 Winds will be rather light through the extended period with mostly
seasonal temps.

&&

.AVIATION...(For the 00Z TAFS through 00Z Thursday evening)
Issued at 515 PM MDT Wed Jul 19 2017

VFR conditions overall through the period. Scattered showers and
thunderstorms will be over parts of southeast WY and the southern
Panhandle through the evening. Gusty winds and brief heavy rain will
be the main threat with these storms with brief MVFR vsbys.

&&

.FIRE WEATHER...
Issued at 306 PM MDT Wed Jul 19 2017

Hot and dry conditions today are in place today across the
district, with occasional breezy west-northwest in shower and
thunderstorm activity. Humidities will be on the rise with a
general increase in moisture. Daily chances for
showers/thunderstorms will persist over the next few days,
especially over the higher elevations of southeast Wyo. Main
concerns with this activity will be lightning as well as gusty and
erratic outflow winds.

&&

.CYS WATCHES/WARNINGS/ADVISORIES...
WY...None.
NE...None.
&&

$$

SHORT TERM...RJM
LONG TERM...ZF
AVIATION...RE
FIRE WEATHER...RJM



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