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000
FXUS65 KCYS 251713
AFDCYS

Area Forecast Discussion
National Weather Service Cheyenne WY
1113 AM MDT Thu Apr 25 2019

.SHORT TERM...(Today through Saturday)
Issued at 355 AM MDT Thu Apr 25 2019

Current KCYS radar loop across the region shows the bands of
locally heavy showers and thunderstorms dissipating or moving
east of the area into central Nebraska early this morning. Expect
a few sprinkles or flurries as we approach sunrise, otherwise
cloudcover will begin to dissipate. Today will be a little nicer
than previously expected, although it will be a little cooler than
yesterday. Expect skies to clear this morning before clouds and
shower redevelop this afternoon. Thankfully, coverage will be much
less and confined to mainly the mountains and perhaps the far
northern NE panhandle in the vicinity of the Black Hills of South
Dakota. High res models show widely scattered showers and even a
few thunderstorms across the Snowy Range, Laramie Range and near
the Pine Ridge where terrain enhanced convergence and localized
llvl instability will produce some light activity into this
evening. Otherwise, it will be noticeably cooler with highs in
the upper 50s to mid 60s across southeast Wyoming and western
Nebraska.

Models show another Pacific upper level trough quickly moving
across Wyoming late Friday. This system looks similar to the one
which moved across the area last night with the trough axis
a bit further north in comparison. With the highest pressure
gradients aloft and a branch of the jet stream over the area late
Friday and Friday night, this system may be more of a wind
producer across the area as 700mb winds over 50 knots and 6 hour
pressure falls approach 8mb to 12mb across the plains. Increased
winds quite a bit through Friday night with good 850 to 700mb
subsidence over the area. Other models are not quite as bullish
with wind speeds, but expect at least windy conditions Friday
night with wind gusts around 35 to 45 mph over much of the area.
Will need to monitor the timing of the highest winds across
southeast Wyoming in the event High Wind headlines may be
warranted. Expect another good chance of showers and thunderstorms
late friday afternoon through the late evening hours due to
marginal instability but good jet dynamics as another cold front
moves across the area late Friday/early Saturday morning.

Models indicate a pleasant day Saturday with highs generally in
the 60s, but near 70 below elevations of 5000 feet. Winds will
gradually decrease through the morning hours as the frontal system
quickly moves east of the region. Expect dry conditions with
mostly sunny skies for weekend outdoor activities.

.LONG TERM...(Saturday night through Wednesday)
Issued at 217 AM MDT Thu Apr 25 2019

Saturday night/Sunday...The next shortwave trough aloft moves
eastward across eastern Montana and eastern Wyoming with some low
and mid level moisture moving across southern Wyoming, where there
is a chance of showers Sunday afternoon south of a Rawlins to
Scottsbluff line. Continued relatively mild on Sunday in the warm
sector.

Monday...Considerably cooler in the wake of a passing cold front
with temperatures mainly in the 40s. Scattered to numerous showers
expected, mainly over our southern counties with a bulk of moisture
ahead of an approaching shortwave trough aloft over Arizona.

Tuesday...Scattered showers continue as the shortwave trough aloft
moves over northern Colorado and cool and moist upslope continues
over our counties. Temperatures still cool with plenty of cloud
cover and precipitation.

Wednesday...The cool temperatures continue as the next trough aloft
moves over Wyoming producing cold air advection and north to
northwest winds at the surface. Enough low and mid level moisture
for at least scattered showers and isolated thunderstorms under the
cyclonic flow aloft.

&&

.AVIATION...(For the 18Z TAFS through 18Z Friday morning)
Issued at 1113 AM MDT Thu Apr 25 2019

VFR expected at all terminals through the period with a few showers
possible vcnty mtns this afternoon and evening.  Some gusty northerly
winds over the Neb Panhandle this afternoon.

&&

.FIRE WEATHER...
Issued at 303 AM MDT Thu Apr 25 2019

Minimal Fire Weather concerns Today and Friday due to recent
precipitation and high daytime humidities. However, concerns will
likely increase Friday night and Saturday as windy conditions are
expected with daytime humidities lowering into the teens on
Saturday. Any concerns should be short-lived however, as the next
cold front moves into the region late this weekend.

&&

.HYDROLOGY...
Issued at 303 AM MDT Thu Apr 25 2019

Above average temperatures over southeast Wyoming resulting in
increasing snowmelt across the mountains. River and stream gauges
show rises across the area, but most areas are still not
observing bankfull flow. Will continue to keep an eye on mountain
streams and creek levels into this weekend due to snowmelt and
some rainfall, but flooding looks unlikely over the next several
days. Another cold front is expected to push across the area
early next week resulting in much cooler temperatures for the high
elevations, which will limit snowmelt.

&&

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

$$

SHORT TERM...TJT
LONG TERM...RUBIN
AVIATION...RE
FIRE WEATHER...TJT
HYDROLOGY...TJT