Area Forecast Discussion
Issued by NWS Cheyenne, WY

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FXUS65 KCYS 250549

Area Forecast Discussion
National Weather Service Cheyenne WY
1149 PM MDT FRI JUN 24 2016

.SHORT TERM...(This evening through Sunday night)
Issued at 300 PM MDT Fri Jun 24 2016

Scattered showers and thunderstorms have developed across most of
the region...especially along and east of the I25 corridor late
this morning. Some strong thunderstorms have been reported...but
nothing severe as of yet. Would not be surprised to see one or two
severe thunderstorms across western Nebraska with marginal shear
and instability values. Dry air has struggled to move into the
forecast area due to the position and strength of the surface
trough still over NW Wyoming this afternoon. As the surface cold
front moves into the region tonight...showers and thunderstorms
are expected to redevelop along and ahead of this front as it
moves southeast. May see nocturnal convection linger after
midnight tonight...especially south and east between
Cheyenne...Scottsbluff and Sidney Nebraska. Do not expect fog to
develop but some low clouds may develop as the cold front moves
across the area. Low clouds will not linger for too long as winds
will increase behind the cold front early Saturday morning.

Expect cooler temperatures for this weekend...with highs ranging
between the mid 70`s to mid 80`s on Saturday and in the 80s to
near 90 on Sunday. It will be pleasant and breezy/very dry behind
the front on PW/s lower below one quarter of an
inch out west. Models show a slight potential of showers and
thunderstorms near the I80 Summit eastward along the Cheyenne
Ridge due to lingering moisture and some upslope flow. Kept a
slight chance of thundershowers for Saturday evening...but it will
be mostly dry with nothing more than a some fair weather cumulus
during the afternoon hours. Winds will then shift into the south
and southeast on Sunday as llvl moisture returns to the central
High Plains...resulting in a slightly higher chance for widely
scattered showers and thunderstorms southeast of a line from
Laramie to Chadron Nebraska.

.LONG TERM...(Monday through Thursday)
Issued at 300 PM MDT Fri Jun 24 2016

Northwesterly flow aloft will be in place early next week with the
mid level ridge centered near the Four Corners region. Good llvl
moisture in east to southeasterly winds will be present across the
plains, with both the GFS and ECMWF showing CAPE values of
1500-2000 j/kg over the Nebraska Panhandle. The storms that
develop should be discrete and have severe potential as bulk
shear is around 45-50 kts. Heights rise slightly on Tuesday. Will
have to watch for strong/severe storms once again, however it may
be more confined to the northern Nebraska Panhandle, closer to the
warm front across South Dakota. Highs will be slightly above
normal through Tuesday then cooling will occur on Wednesday behind
a cold front. The severe threat will be less on Wednesday with
less instability. The subtropical ridge that has been so strong
across the West begins to weaken by Thursday. Daily chances of
aftn/evening convection along with more normal temps will prevail.


.AVIATION...(For the 06Z TAFS through 06Z Saturday night)
Issued at 1149 PM MDT Fri Jun 24 2016

Shower activity has redeveloped across southeast Wyoming at 05Z,
likely with some embedded thunder as well especially near KLAR and
as this activity moves east towards KBFF. Kept this in the TAF
through 08-09Z, and includes KCYS. Will have to watch for MVFR
stratus behind the front as it slides south across the area
overnight, however current guidance keeps the terminals VFR. Gusty
northwest winds are still expected in the wake of the front across
the plains tomorrow, while winds will be more out of the west-
southwest across the high country. Gusts to 25 kts are likely.


Issued at 219 PM MDT Fri Jun 24 2016

Critical fire weather conditions are struggling to develop across
east central Wyoming early this afternoon due to light winds.
Humidities are generally around 15 percent with pretty warm
temperatures across the area. West winds are starting to increase
across far western Converse will keep the Red Flag
Warning going through this evening. Guidance has struggled with
low level moisture and wind speeds well as the speed
of the upper level Low moving across Montana tonight and
Saturday...therefore not a whole lot of confidence with critical
fire weather conditions for Saturday. After a brief dry period
this weekend...showers and thunderstorms will return to the region
by early next week.


.CYS Watches/Warnings/Advisories...
WY...Fire Weather Watch from 11 AM MDT Saturday through Saturday
     evening for WYZ301.



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