Area Forecast Discussion
Issued by NWS Cheyenne, WY

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000
FXUS65 KCYS 110535
AFDCYS

Area Forecast Discussion
National Weather Service Cheyenne WY
1135 PM MDT Thu Aug 10 2017

.SHORT TERM...(This evening through Saturday night)
Issued at 300 PM MDT Thu Aug 10 2017

Unsettled weather to continue with daily chances of showers and
thunderstorms as disturbances move through the persistent
northwest flow.

Currently...Cold front bisects the CWFA across Albany County this
afternoon. Temperatures have been quite cool with low to mid 60s
across the east and upper 60s and low 70s out by Rawlins and
southwest/central Wyoming. Was an area of showers that moved
across our northern zones through the morning that is exiting off
into Nebraska this afternoon. More robust convection being
observed across northern Colorado this afternoon. Looks like
Cheyenne will get hit by the northern edge of these thunderstorms
over the next couple hours. Water vapor imagery showing upper
shortwave associated with the front is moving into the area, which
may fill in the showers activity before pushing the front further
south this evening.

Still looks good for fog tonight as precip comes to an end and
winds shift easterly to southeasterly, especially in areas that
received rainfall today. Continued the area of fog in the forecast
for east of the Laramie Range overnight. Fog could persist east of
the Laramie Range pretty much all morning Friday before lifting
around noon time.

ECMWF shows another shortwave for Saturday moving south out of the
Dakotas and eastern Montana that will bring another round of
widespread rain Saturday night.

.LONG TERM...(Sunday through Thursday)
Issued at 300 PM MDT Thu Aug 10 2017

Sunday...Northwest flow aloft prevails and with a possible shortwave
trough aloft passage and upslope southeast winds, believe we will
see isolated to scattered afternoon and evening showers and
thunderstorms, mainly east of a Laramie to Lusk line. Mild
temperatures continue.

Monday...Decent warming trend expected as the ridge aloft builds
overhead. Showers and thunderstorms will be more isolated due to
warmer temperatures aloft, with the best areal coverage over the
mountains.

Tuesday...Continued warm based on projected 700 mb temperatures.
Enough low and mid level moisture and instability for isolated to
scattered afternoon and evening showers and thunderstorms.

Wednesday...With zonal flow aloft, the atmosphere dries out somewhat,
making for a mostly dry day along with even warmer temperatures due
to less cloud cover and fewer showers and thunderstorms to limit
heating.

Thursday...Continued quite warm with airmass modification and zonal
flow aloft. Another mostly dry day due to limited low and mid level
moisture.

&&

.AVIATION...(For the 06Z TAFS through 06Z Friday night)
Issued at 1127 PM MDT Thu Aug 10 2017

Satellite imagery shows low clouds beginning to expand northward
along the South Laramie Range as of 0530Z. Still expect MVFR
ceilings with some IFR visibility in fog to affect KCYS, KBFF, and
KSNY through 15Z. Low clouds may take some time to burn off Friday
so afternoon convection will likely be later in the day. Expect
scattered thunderstorms to develop by 19Z over the higher terrain
of SE WY and spread east and southeast into the Panhandle through
the early evening hours. Strong wind gusts and hail are possible
with the strongest storms.

&&

.FIRE WEATHER...
Issued at 300 PM MDT Thu Aug 10 2017

Minimal fire weather concerns as a cool and moist airmass remains
in place across southeast Wyoming and Nebraska Panhandle. Upper
ridge over the northern Rockies will keep a northwest flow over
the area with disturbances moving across our area from the
northwest on a daily basis. Rainshowers and thunderstorms look to
occur on a daily basis with these disturbances, so most areas
should see measurable rainfall at least through the middle of next
week.

&&

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

$$

SHORT TERM...GCC
LONG TERM...RUBIN
AVIATION...DEL
FIRE WEATHER...GCC



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