Area Forecast Discussion
Issued by NWS Cheyenne, WY

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FXUS65 KCYS 240527

Area Forecast Discussion
National Weather Service Cheyenne WY
1127 PM MDT Sun Oct 23 2016

Issued at 652 PM MDT Sun Oct 23 2016

A generally quiet night is in store for much of the area. The only
concern for the evening update is the potential for gusty winds in
the vicinity of the Pine Ridge overnight. The GFS and NAM are both
showing a 40-45 knot H85 jet developing over the western Panhandle
between 06z and 12z, slightly below a pronounced low-lvl inversion
already in place over the area. Increased wind (gusts) into the 40
to 50 MPH range after midnight. This should remain confined to the
higher terrain, so do not believe any highlights will be necessary
but will need to monitor trends to see if this is likely to spread
into lower elevations around CDR/AIA as well. The overall forecast
is in excellent shape this evening. Updates have been sent.


.SHORT TERM...(This evening through Tuesday night)
Issued at 207 PM MDT Sun Oct 23 2016

Mainly quiet weather looks to hold over the CWA through Tuesday
with no significant systems affecting the region. A weak surface
boundary banked up against the higher terrain will erode east
later tonight into Monday as a surface high centered over the
northern plains slips southeast and lee troughing develops over
the high plains. Varying amounts of high cloudiness will continue
to stream over the CWA through Monday ahead of a large upper
trough/low off the west coast.  Mild to warm temperatures will
continue across the CWA through Tuesday. A weak shortwave will
eject east across the central Rockys Monday night into Tuesday and
should bring some showers to mainly the higher mtns of southeast
Wyoming at that time.

.LONG TERM...(Wednesday through Sunday)
Issued at 207 PM MDT Sun Oct 23 2016

Models/ensembles are in good agreement in showing the upper level
ridge dominating the Rockies. This will allow for dry and
unseasonably mild conditions for this time of year. The fire
danger does not look to be much of an issue on Wednesday, but we
will have to keep an eye on Thursday for areas east of the Laramie
Range where humidities will be quite low and wind speeds may be a
bit gusty.

The main concern during this period will be the timing of the
shortwave moving through northern Rockies. The GFS appears to be
the fastest in moving this wave through the region late Thursday
night into Friday, while the GEM/UKMET/ECMWF/GEFS are about 12 to
24 hours slower and a bit more amplified. At this point, we are
favoring the slower solutions at this time, since the GFS tends to
be a bit too quick in ejecting shortwaves out of the Eastern
Pacific Trof. If this shortwave does comes through a little later
and slower this weekend, we may be faced with a little better
precipitation chances on Saturday along with higher wind speed
potential. Otherwise, it does appear things may cool off a bit on
Saturday, but upper level ridging should move back into the
picture on Sunday which allow for another mild day.


.AVIATION...(For the 06Z TAFS through 06Z Monday night)
Issued at 1124 PM MDT Sun Oct 23 2016

VFR conditions will prevail through the TAF period. Terminals over
the northern Panhandle (KAIA/KCDR) may experience a period of wind
gusts between 20 and 30 knots between 09z-12z, but it appears that
the strongest winds will remain over higher terrain along the Pine
Ridge. Otherwise, expect light winds tonight and a return of gusty
winds to areas along/west of the Laramie Range on Mon. Expect BKN-
OVC coverage of high clouds around 20k feet AGL.


Issued at 207 PM MDT Sun Oct 23 2016

No significant concerns seen through at least the early part of
the week as air moisture will be a little higher. There will be
some gusty winds in the afternoons over western areas but fuels
not critical and min rhs around 20% Monday. Even higher min RHs
Tuesday. A few showers possible mainly ovr Carbon county mainly
Monday night.




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