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Area forecast discussion
National Weather Service Cheyenne Wyoming
1116 am MDT Wed Jun 20 2018

Short term...(today and tonight)
issued at 311 am MDT Wed Jun 20 2018

An upper level vorticity Max continues to rotate to the north of
the region, bringing light rain and low cloud cover to Niobrara
County, as well as the northwestern-most counties along the
Nebraska Panhandle. The possibility of light showers in these
areas will continue through about daybreak. Patchy fog will be
noted where the highest rainfall amounts were measured over the
course of yesterday's storms. Any fog that forms overnight will
dissipate as the sun rises.

A weak cold front will pass from the northwest to the southeast
today bringing a slight chance of showers and afternoon
thunderstorms to the area. Maximum daytime temperatures will
continue to be cool, sitting around the mid-60s. Skies will clear
behind the frontal passage as a dry northwest flow aloft sets up
over the area.

Long term...(thursday through tuesday)
issued at 311 am MDT Wed Jun 20 2018

Thursday could be the next interesting day this week as a
shortwave passes through the flow aloft, accompanied by a strong surface
cold front, which will move through the region from west to east.
0-6 km shear values indicate that rotating storms are possible
and MUCAPE values will approach about 1500 j/kg. As these storms
look to be high-based, the threat for the day will be strong winds
and large hail associated with any storms that develop in the
afternoon and evening.

Shower and thunderstorm activity continue through Friday as a
shortwave trough passes quickly through the region. By Saturday,
a wet pattern will set in once again and continue through the
weekend and into the beginning of the week as an upper level
closed low passes directly over the region. Closed lows generally
indicate the development of an unstable environment with
distinctly cold temperatures aloft capable to supporting
strong thunderstorms. With this kind of set-up, severe weather
may be a factor come Sunday.

&&

Aviation...(for the 18z tafs through 18z Thursday morning)
issued at 1116 am MDT Wed Jun 20 2018

VFR prevailing though there may be some patchy MVFR cigs affecting
kcdr and kaia early this afternoon with showers in those areas as
well. Other wdly sctd showers and a few storms this afternoon into
early this evening across the Panhandle. Clearing this evening.

&&

Fire weather...
issued at 311 am MDT Wed Jun 20 2018

Fire concerns remain minimal for the near-term as a cool and wet
pattern persists into the weekend. Minimum relative humidity values will be about
25 % or more across the higher terrain today and winds generally
light. Wind gusts to 25 kts will be reached this afternoon as a
weak cold front passes through the region. Another round of
showers and afternoon thunderstorms is expected with a strong cold
frontal passage Thursday. Friday looks to be the driest day this
week before more showers and afternoon thunderstorms develop over
the weekend.

&&

Hydrology...
issued at 311 am MDT Wed Jun 20 2018

The previous Flash Flood Watch was cancelled earlier this morning
as the threat of heavy rain has subsided. Although periods of
light to moderate rainfall will continue today, rainfall rates are
no longer expected to pose a significant threat of widespread
flash flooding.

&&

Cys watches/warnings/advisories...
Wyoming...none.
NE...none.
&&

$$

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