Area Forecast Discussion
Issued by NWS Cheyenne, WY

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FXUS65 KCYS 142240

Area Forecast Discussion
National Weather Service Cheyenne WY
340 PM MST Tue Feb 14 2017

.SHORT TERM...(Tonight - Thursday Night)
Issued at 314 PM MST Tue Feb 14 2017

No major forecast concerns over the next few days. A strong upper-
level ridge will remain intact over the central Rockies through at
least Thursday afternoon. A significant warming trend is likely in
the next 48 hours as H7 temperatures soar to +5 to +7 deg C across
much of the CWA by 18z Thursday. The models continue to show a dry
column which suggests plentiful sunshine and little/no chances for
precipitation through the period. On Wednesday, lee troughing will
result in a rapidly increasing surface pressure gradient along the
spine of the Laramie Range. The GFS shows an ARL-BRX MSLP gradient
peaking at 4 mb around 15z-21z Wednesday w/ 40 knots flow at H8. A
few wind gusts of 50-60 MPH are likely, but prefer to see stronger
flow aloft to justify high wind headlines. The only other concerns
involve elevated fire weather conditions on Wed/Thu afternoon with
widespread 60s and even 70s for highs along/E of the Laramie Range
pushing RH values down near 10 percent at CYS. Winds will be gusty
in some locations as well, so meteorological conditions could very
well exceed Red Flag Warning criteria. However, opted against fire
weather headlines given generally marginal conditions and the fact
that it is still very early in the season with fuels not conducive
for large fire growth.

.LONG TERM...(Friday - Tuesday)
Issued at 314 PM MST Tue Feb 14 2017

Upper level ridge will shift eastward on Friday as a shortwave
trough lifts northeastward from WY into eastern MT.  There will a
brief period on Friday morning where gusts to 50 mph will be
possible at Bordeaux before the gradient weakens.  The weather over
the weekend will be very nice with weak southerly low to midlvl flow
and highs around 15 degrees above normal.   A strong shortwave is
progged to move over WY on Monday with widespread breezy to windy
conditions and slightly cooler temps.  The ECMWF does show
orographic snows returning to the Sierra Madre and Snowy Ranges by
Sunday night into Monday morning, however amounts would be limited
overall by the progressive nature of the system.


.AVIATION...(For the 18Z TAFS through 18Z Wednesday afternoon)
Issued at 946 AM MST Tue Feb 14 2017

VFR conditions through the taf period under mostly clear skies.
Northerly winds will gust to 15-25 kts at CYS/SNY through the


Issued at 230 AM MST Tue Feb 14 2017

High pressure to remain in control of the weather across southeast
Wyoming and Nebraska Panhandle through the remainder of the week.
Warmer temperatures and drier air will combine with increasing
west to southwest winds Wednesday and Thursday to create elevated
fire weather conditions for areas east of the Laramie Range during
the afternoon hours. Afternoon humidities look to be critical both
Wednesday and Thursday with low teens humidity and winds gusting
in excess of 25 MPH. Fast moving grass fires are a possibility as
snow pack is pretty much gone in these areas. Since Fuels are
reported not ready though, fire weather concerns are low.




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