Area Forecast Discussion
Issued by NWS Cheyenne, WY

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FXUS65 KCYS 010414

Area Forecast Discussion
National Weather Service Cheyenne WY
1014 PM MDT TUE MAY 31 2016

Issued at 843 PM MDT Tue May 31 2016

Water vapor/upper air analysis showed a weak shortwave moving
into the central high plains this evening. Widely scattered
convection that developed mid-late afternoon over southeast WY
has dissipated. partly cloudy skies this evening will become
clear overnight. No changes to the zones or grids.


.SHORT TERM...(This evening through Thursday night)
Issued at 229 PM MDT Tue May 31 2016

Upper low evident on satellite over North Dakota with west-
northwesterly flow over the CWA on the periphery of this low.
Radar depicting just a few showers over far southeast Wyoming
near the Colorado border with bulk of activity to the south. These
should persist for the rest of the afternoon before dissipating
early this evening.

Similar weather expected for Weds under WNW flow aloft with temps
mild and winds generally on the light side. A few showers could
pop up over the mtns near the Colorado border again Weds afternoon
with some low instability present. On Thursday an upper high over
the desert SW should expand some into the area allowing for warmer
temps...about 10 degrees warmer for highs from Weds. Mainly dry
except for a bit of convection possible mainly over far western
parts of the CWA.

.LONG TERM...(Friday through Tuesday)
Issued at 229 PM MDT Tue May 31 2016

The main concern with this portion of the forecast package will
be how warm temperatures will be this weekend and early next
week. latest look at the various ensembles is showing a very
anomalous upper level ridge setting up over the northwest U.S..
This will set the stage for mostly dry and warm conditions this
weekend into early next week especially in the western half of the
forecast area. The main question will be the how the cutoff low in
Northern California tracks. The GFS appears to be the most
progressive in tracking this feature east through the southern
Rockies early next week. Meanwhile, the ECMWF is much slower in
tracking it eastward. The ensembles are showing quite a bit of
spread. With such a large spread, we are favoring more of the
ensemble mean which may bring some scattered showers/tstms into
our forecast area early next week.


.AVIATION...(For the 06Z TAFS through 06Z Wednesday night)
Issued at 1011 PM MDT Tue May 31 2016

VFR prevails with scattered to broken clouds from 7000 to 9000
feet AGL. Localized MVFR at Laramie in low clouds and fog from
09Z to 15Z. Isolated showers Wednesday afternoon and early
evening at Cheyenne, Laramie and Sidney.


Issued at 229 PM MDT Tue May 31 2016

Fire weather concerns expected to remain low for the rest of the
week as fuels remain non-critical. warmer afternoon temperatures
late in the week should result in minimum humidities around 20
percent over lower elevations.


Issued at 229 PM MDT Tue May 31 2016

Unseasonably warm temperatures later this week through the weekend
will induce rapid snowmelt runoff this weekend. Those living along
the Upper North Platte River including locations between Saratoga
and Sinclair WY should should be prepared for rising river levels,
which will approach or exceed flood stage late this weekend into
early next week. Meanwhile, the Laramie River will slowly rise,
while points between Fort Laramie WY and Minatare NE on the Lower
North Platte River will remain nearly steady or slowly recede.


.CYS Watches/Warnings/Advisories...


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