Area Forecast Discussion
Issued by NWS Cheyenne, WY

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068
FXUS65 KCYS 231714
AFDCYS

Area Forecast Discussion
National Weather Service Cheyenne WY
1114 AM MDT MON MAY 23 2016

.UPDATE...
Issued at 1018 AM MDT Mon May 23 2016

Scattered showers and thunderstorms are expected to develop across
much of southeast WY and the western NE panhandle by mid/late this
afternoon. The greatest coverage should be along the I-80 corridor
between Laramie and Sidney as a weak H25 jet lifts across northern
CO. High-resolution models are in agreement with this thinking, so
the main change to the inherited forecast was to bump up PoPs into
the scattered category over those areas. Also adjusted temperature
and cloud trends through the late morning/early afternoon based on
recent observations.

&&

.SHORT TERM...(Today through Wednesday)
Issued at 300 AM MDT Mon May 23 2016

Today...Shortwave moves across our counties near peak heating with a
weak low level convergence boundary across southeast Wyoming. With a
low and mid level theta-e ridge axis over southeast Wyoming, expect
isolated thunderstorms to develop this afternoon south of a Rawlins
to Douglas line. Instability and shear will be limited so expect
garden variety type storms.

Tonight...Thunderstorms dissipating in the evening with loss of
daytime heating, then clearing skies after midnight.

Tuesday...More active pattern as deeper low level moisture streams
northward into our Nebraska panhandle counties and a well
established dryline develops along the Wyoming and Nebraska state
line in the afternoon. Based on shear and instability parameters, a
few storms over the southern Nebraska panhandle may become severe
along with the Storm Prediction Center slight risk outlook. Isolated
to scattered less strong storms expected elsewhere.

Tuesday night...Decent chance for evening thunderstorms across
western Nebraska, then clearing skies after midnight with a few
showers possible over western Nebraska.

Wednesday...Low level winds becoming southwest with drier low level
air invading our counties. Will have enough mid level moisture to
generate isolated high based afternoon thunderstorms, with limited
rainfall at the ground due to fairly dry low levels.

.LONG TERM...(Wednesday night through Sunday)
Issued at 330 AM MDT Mon May 23 2016

Latest medium range model guidance continues to depict an active
and unsettled weather pattern for our CWA as a long wave upper
trough dominates the Rockies and Great Plains. Convective coverage
will vary from day to day, with the greatest coverage of showers
and thunderstorms Thursday through Friday as a upper low slowly
moves across Colorado and northern New Mexico. Winds for the most
part will be light with a fairly weak pressure pattern across the
region. Temperatures will average near to slightly below seasonal
normals. For the valleys and plains, high temperatures will range
from the 60s to mid 70s, with low temperatures in the 40s. For
the high terrain, high temperatures will range from 45 to 55
degrees, with low temperatures from 25 to 35 degrees.

&&

.AVIATION...(For the 18Z TAFS through 18Z Tuesday afternoon)
Issued at 1108 AM MDT Mon May 23 2016

Another round of convection expected this afternoon...mainly along
and east of the Laramie Range. Looks like the convection today
will be confined to areas along and southeast of a line from
Alliance to Cheyenne. Did go with VCTS wording in the 18Z TAFs for
airports in this area this afternoon through sunset.

&&

.FIRE WEATHER...
Issued at 300 AM MDT Mon May 23 2016

No fire weather concerns based on projected winds and humidities.


&&

.HYDROLOGY...
Issued at 300 AM MDT Mon May 23 2016

Cooler temperatures for elevations above 9000 feet where there is
still abundant snowpack will reduce mountain snowmelt rates this
week. The Upper North Platte River at Saratoga and Sinclair,
Wyoming responded with slower rises. The Laramie River at Laramie
is forecast to rise to moderate flood stage this week. Minor to
moderate flooding will continue along the Lower North Platte River
near Fort Laramie, Wyoming, and Henry, Mitchell and Minatare,
Nebraska. Widely scattered showers and thunderstorms will
generally produce light to moderate rainfall. Locally heavier
rainfall will be possible for the plains on Tuesday and Thursday.

&&

.CYS Watches/Warnings/Advisories...
WY...None.
NE...None.
&&

$$

UPDATE...Hammer
SHORT TERM...Rubin
LONG TERM...Jamski
AVIATION...GCC
FIRE WEATHER...Rubin
HYDROLOGY...Jamski



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