National Weather Service Weather Forecast Office

• Home
• Site Map
• News
• Organization
• Search for: NWS All NOAA 

000
FXUS65 KCYS 150508
AFDCYS

Area Forecast Discussion
National Weather Service Cheyenne WY
1108 PM MDT Thu Sep 14 2017

.UPDATE...
Issued at 1024 PM MDT Thu Sep 14 2017

Area of showers and embedded thunderstorms currently expanding
across the Panhandle in a zone of weak elevated CAPE and warm
advection ahead of the shortwave over western CO. This activity
should continue to lift north and be primarily elevated over the
low level frontal zone through the late evening hours. Increased
POP to likely over the Panhandle to account for recent radar
trends.

&&

.SHORT TERM...(This evening through Saturday)
Issued at 245 PM MDT Thu Sep 14 2017

Shortwave currently across southern Nevada is still progged to lift
rapidly northeastward through the night and be located over
northeast Wyoming by midday Friday.  Increasing ascent ahead of it
will keep scattered to numerous showers and isolated tstms going
through much of the night.  Cannot rule out an isolated storm with
small hail, however the threat looks rather small with limited
instability.  The coverage of showers will generally decrease into
sunrise Friday in the subsidence behind the shortwave trough.  West
winds will become breezy for areas near and west of the Laramie
Range by Friday morning at the 850mb CAG-CPR gradient increases to
around 40 meters.

There will be an overall lull in precip during the day on Friday,
except across far northwestern zones.  Main upper trough will move
across Wyoming on Saturday, with the associated sfc fropa on Friday
aftn/evening.  Upper level divergence will be on the increase by
late Friday evening into Friday night, with higher PoPs spreading
over the plains.  Snow levels will drop to around 10000 ft by
Saturday morning, so could see 1-3 inches in the higher peaks of the
Sierra Madre and Snowy Ranges. Saturday`s highs will be some of the
coolest we have seen in quite a while, with most locations
struggling to get above the mid 60s.  Shower chances will decrease
after 18Z Saturday in the wake of the upper trough.

.LONG TERM...(Saturday night through Thursday)
Issued at 245 PM MDT Thu Sep 14 2017

Warmer temperatures seen for the CWA Sunday and Monday as the area
will be in between systems with the next upper trough digging into
the Pacific northwest by late Monday. One shortwave may bring some
showers to the plains Sunday evening otherwise dry weather expected.
Cooler and wetter conditions then arrive across the CWA in the
Tuesday through Thursday time period as the upper trough amplifies
over the western CONUS and a cold front pushes across the CWA late
Tuesday. Most widespread rain should be later Weds into Thursday
as a shortwave lifts across the region.

&&

.AVIATION...(For the 06Z TAFS through 06Z Friday night)
Issued at 1105 PM MDT Thu Sep 14 2017

Main concern tonight continues to be IFR/LIFR possibilities
across the northern Panhandle over into east/central Wyoming.
Latest HRRR showing a northeast cold front dropping into this area
after 06Z with upsloping northeasterly winds. Did bring KCDR and
KAIA down to IFR with it extending over to KLSK and maybe KDGW.
KBFF is being shown as down on latest HRRR, but not a favorable
wind direction, so kept MVFR. Then windy most of the day Friday.

&&

.FIRE WEATHER...
Issued at 245 PM MDT Thu Sep 14 2017

No fire weather concerns through the weekend.  Cooler temperatures
will occur on Friday and Saturday with minimum afternoon humidity
values remaining above 25 percent.  There will be a good chance of
showers across much of the region from this evening through Saturday
morning.

&&

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

$$

UPDATE...DEL
SHORT TERM...ZF
LONG TERM...RE
AVIATION...GCC
FIRE WEATHER...ZF