Area Forecast Discussion
Issued by NWS Cheyenne, WY

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000
FXUS65 KCYS 150143
AFDCYS

Area Forecast Discussion
National Weather Service Cheyenne WY
743 PM MDT Thu Mar 14 2024

.KEY MESSAGES...

1) Light to moderate snowfall accumulations will be likely
across the lower elevations along and east of the Laramie Range,
with the higher totals occurring over the mountains.

2) Normal temperatures at the end of the weekend will giveaway
to well above normal temperatures to begin next week.

3) Elevated fire weather may return by early next week.

&&

.UPDATE...
Issued at 733 PM MDT Thu Mar 14 2024

Snow showers continue across portions of southeast Wyoming this
evening, with 1-2 inches of additional accumulation possible
through the evening. The Winter Weather Advisory for the Sierra
Madre Range was allowed to expire on time at 6 PM MDT. Only
major changes made for this update was to add Patchy Fog for
Laramie County. As the snow comes to an end tonight, light winds
and low dew point depressions may lead to some fog development for
much of Laramie County along I-80. Additionally, northeasterly
winds will begin to turn more easterly overnight leading to
light upslope flow along I-80 between Pine Bluffs and Cheyenne.
Some fog may develop in the Laramie Valley overnight as well,
but did not include fog for that location for now. Will not be
doing any fog headlines at this time and will let the overnight
crew take another look at the fog potential.

&&

.SHORT TERM /THROUGH FRIDAY NIGHT/...
Issued at 102 PM MDT Thu Mar 14 2024

Round two of the snow storm began ahead of schedule with the
first snow beginning around 10am for areas south of the North
Platte River Valley. Hard to determine how much snow has fallen
given much of the area has seen a steady blustery wind in the
range of 20-25 mph with gusts up to 35 mph, this has created
instances of blowing and drifting snow across the region. Radar
trends over the past several hours show a steady stream of
precipitation moving east to west across SE Wyoming and the
western Nebraska Panhandle. Winds have stayed out of the east to
northeast and as long as this continues with the upslope flow we
will continue to see light to moderate snow continue into the
overnight hours.

There is a chance for a window of steady moderate snow during
the evening with the arrival of the upper level jet dynamics,
although latest models have it a bit more south than previous
runs but still in close proximity that some moderate snow may
still be possible for portions of the I-25 corridor from
Cheyenne to Wheatland and the I-80 corridor from the Summit to
Pine Bluff. Precipitation should be coming to end heading into
Friday but skies should stay mostly cloudy which will keep the
diurnal curve pretty low with minimal deviation from daytime
high and low temperatures. There could be a chance for some low
level clouds to hang on and or transition to patchy areas of fog
to develop. With temperatures below freezing this may create
some hazardous conditions Friday night.

&&

.LONG TERM /SATURDAY THROUGH THURSDAY/...
Issued at 102 PM MDT Thu Mar 14 2024

By Saturday, southeast Wyoming and western Nebraska come under the
influence of the high pressure side of a Rex Block. This pattern
will bring warmer temperatures with highs near 5 degrees above-
average. Temperatures Sunday are forecast to be a few degrees cooler
than they were Saturday, especially in the northern panhandle and
east-central Wyoming where a weak backdoor cold front pushes through
from the northeast. Overall this is expected to be a dry cold front,
mainly turning winds to the east/northeast with wind gusts 30 to 40
mph possible. The high pressure side of the Rex Block then shifts
back east and takes back over with much warmer temperatures, dry
conditions, and generally light west winds. Long range models
finally show the Rex Block breaking down Tuesday into Wednesday as a
trough in the PACNW and strong low pressure system in central Canada
drop southward into the CONUS. The breakdown of the ridge will lead
to temperatures a few degrees cooler, but overall still well-above-
normal temperatures and dry conditions.

&&

.AVIATION /00Z TAFS THROUGH 00Z SATURDAY/...
Issued at 544 PM MDT Thu Mar 14 2024

Look for snow to slowly come to an end across southeast Wyoming
this evening. Still...IFR conditions can be expected at KCYS and
KLAR through this evening before the snow ends. Some concern
about dense fog at KCYS Friday morning with abundant low level
moisture from recent snow and continuing upslope wins. Will try
to get a better handle on this fog with the 06Z TAFs.

&&

.CYS WATCHES/WARNINGS/ADVISORIES...
WY...Winter Weather Advisory until 6 AM MDT Friday for WYZ104-106-
     109-115-117>119.
     Winter Storm Warning until 6 AM MDT Friday for WYZ110-114-116.
NE...None.

&&

$$

UPDATE...AM
SHORT TERM...AW
LONG TERM...LEG
AVIATION...GCC


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