Mc Grew, Nebraska Weather Forecast Discussion

259
FXUS65 KCYS 042052
AFDCYS
Area Forecast Discussion
National Weather Service Cheyenne WY
252 PM MDT Sat Oct 4 2025
.KEY MESSAGES...
- There is a Slight Risk (Level 2 of 5) for severe weather
  across southeast Wyoming and western Nebraska today.
- Strong winds possible around Arlington late Saturday night.
  Gusts over 50 MPH possible.
- Precipitation chances continue into Sunday with temperatures
  10 to 20 degrees cooler than Saturday.
&&
.SHORT TERM /THROUGH SUNDAY NIGHT/...
Issued at 247 PM MDT Sat Oct 4 2025
With the upper-level trough moving into the CWA this afternoon,
cloud cover and precipitation coverage have increased across the
western portion of the CWA. Current radar shows fairly widespread
coverage of showers and storms west of the Laramie Range, with
observations and webcams confirming this. Based on observations,
the cold front associated with this strong trough appears to be
through Carbon County, with temperatures behind the front in the
40s. Ahead of the front, much of the CWA sits in the warm
sector with temperatures in the 60s and 70s, with some isolated
80s in the Nebraska panhandle. As the front pushes through,
warm, moist air in the warm sector will be lifted, supporting
multiple rounds of precipitation this afternoon and evening.
Instability will also be present in the warm sector, allowing
for thunderstorms to develop. Instability looks marginal at this
time, however, Hi-Res guidance suggests a few linear/bowing
segments developing across the area which could produce a few
severe wind gusts and small hail. Coverage of precipitation will
be widespread, with most locations in the CWA likely to see
some rain accumulations. Most models have the cold front across
the CWA by late evening, at which point most of the precipitation
will also be out of the CWA.
Heading into Saturday night, lingering stratiform precipitation
can be expected in the mountains and in Converse, Niobrara and
northern Carbon and Albany Counties. Wrap around moisture from
the surface low in central Wyoming could support precipitation
in these areas overnight. Precipitation overnight in the
mountains will also lead to some light snow accumulations in the
Snowy and Sierra Madre Ranges above 9000 feet. Flakes are
unlikely to make it down to the surface in the adjacent high
valleys, but also cannot be fully ruled out as overnight lows
fall into the 30s. Besides precipitation, winds will also pick
up in the usual southeast Wyoming wind prones overnight. As the
surface low tracks to the northeast, MSLP gradients over and
west of the Laramie Range will increase slightly around
midnight, increasing winds aloft to about 55 kts. Decent
subsidence will also exist which could help get some of these
stronger winds down to the surface. However, other parameters
like 850 and 700 mb heights do not favor high winds. Even MSLP
gradients do not look strong enough to support high winds.
Regardless, did decide to increase winds over the wind prones,
especially the Arlington zone, as this would be the most likely
area to see 60 MPH wind gusts. Held off on issuing any high wind
headlines at this time as confidence is low and the window for
high winds will be short. By early Sunday morning, winds will
already be weakening.
Much cooler temperatures are expected Sunday behind the front. 700
mb temperatures will be hovering below zero, leading to highs mostly
in the 40s and 50s. These highs will be about 10 to 20 degrees
below average for early October. A weak shortwave will impact
the CWA Sunday evening as the main trough still sits over much
of the northern Rockies. This shortwave will lead to scattered
light showers throughout the day, that will then turn into
stratiform precipitation overnight. While showers will be
possible over most of the CWA during the day, the stratiform
precipitation will mostly be confined to the Snowy and Laramie
Ranges and Interstate 25 corridor. Given the cold temperatures
overnight, the South Laramie Range could see a dusting of snow
while the Snowys will likely pick up an inch or two above 8000
feet. Given the cold temperatures during the day, overnight lows
Sunday night will also be pretty cold. Will have to monitor
areas west of the Laramie Range for freezing temperatures early
Monday morning.
&&
.LONG TERM /MONDAY THROUGH FRIDAY/...
Issued at 247 PM MDT Sat Oct 4 2025
Monday, the upper level trough starts to exit the
Intermountain West and enter the Northern Plains. The cooler air
behind the trough looks to stay for a couple of days with 700mb
temperatures between -1 and -3C. This will keep our high
temperatures for Monday and Tuesday into the 50`s and 60`s. A ridge
starts to build into the intermountain West Tuesday into Wednesday.
This ridge will increase 700mb temperatures into the 5 to 7C range
which will translate our high temperatures raising into the 60`s and
70`s. There is a weak shortwave that pushes through the
Intermountain West however it looks like the stronger vorticity
stream will just be to north of the Southeast Wyoming area. So our
region looks to stay dry Wednesday. The ridge strengthens behind the
weak shortwave so Thursday and Friday will remain in the 60`s and
70`s. Overnight temperatures look to remain in the 30`s and 40`s for
the long term period a clear signal that winter will be here soon.
&&
.AVIATION /18Z TAFS THROUGH 18Z SUNDAY/...
Issued at 1147 AM MDT Sat Oct 4 2025
Active weather expected at all terminals today as a large scale
storm system moves across the forecast area. A strong cold front
will push across the area, bringing widespread precipitation.
Showers and thunderstorms are expected, with some storms having the
capability of producing strong wind gusts. Moderate to heavy rain
can also be expected, which will likely cause visibility drops below
VFR criteria at times. Coverage of precipitation will lessen later
this evening, however a few lingering scattered showers and
storms will be possible. Behind the cold front, low CIGs will
start to build in, mainly affecting areas west of the Laramie
Range overnight. More precipitation and low stratus will move in
on Sunday.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...None.
NE...None.
&&
$$
SHORT TERM...SF
LONG TERM...MM
AVIATION...SF

NWS CYS Office Area Forecast Discussion