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000
FXUS65 KCYS 130439
AFDCYS

Area Forecast Discussion
National Weather Service Cheyenne WY
1039 PM MDT Fri Apr 12 2024

.KEY MESSAGES...

- Above normal temperatures expected across much of the region
  Friday and through the weekend. Afternoon highs in the upper
  60s and 70s across the area.

- Elevated to locally critical fire weather conditions possible
  in the afternoon Friday through Sunday.

- Potential for a storm system to impact the region next week,
  but confidence on any expected impacts are low at this time.

&&

.UPDATE...
Issued at 324 PM MDT Fri Apr 12 2024

Fuels personnel just updated fuels to NO across western Carbon
County...which prompted the cancellation of the Fire Weather
Watches for Saturday and Sunday. Updates have been sent.

&&

.SHORT TERM /THROUGH SUNDAY/...
Issued at 240 PM MDT Fri Apr 12 2024

Stationary leeside front runs from roughly Sidney...north to
Guernsey to Gillette this afternoon. West of this
front...dewpoints in the upper teens and low 20s being reported.
East of the front...dewpoints in the low 30s are being observed.
Pretty quiet day ongoing so far. Elevated fire weather
conditions out near Rawlins this afternoon with humidity right
around 15 percent and wind gusts in the mid 30mph range. Held
off on any fire headlines for today as Rawlins is the only
station reporting critical fire weather conditions at this time.
Next Pacific low pressure system off the coast of northern
California at this time. This feature may come into play for
critical fire weather conditions over the weekend.

Upper 700mb ridge axis passes into the Cheyenne CWA this evening
and into western Nebraska Saturday morning. GFS 700 and 750mb
winds increase overnight tonight up near 30kts that continue
through 18Z Saturday. Given what happened at Rawlins
today...decided to issue a Fire Weather Watch for FWZs 422 and
423 for Saturday afternoon. Local fire headline guidance showing
some moderate to high critical fire weather conditions out by
Rawlins Saturday afternoon. Not totally convinced yet on Red
Flag Conditions and will let the evening and overnight crews
take another look before issuing a warning.

California low moves onshore across central California Saturday
afternoon and into southern Utah/Nevada Saturday evening. Upper
ridge builds back over the CWA. GFS soundings for Carbon County
showing winds off the surface up to 35-40kts mixing down to the
surface. Better chances for critical fire weather conditions
Sunday for Carbon County. As for Laramie County...GFS showing a
narrow ribbon of stronger 800mb southeasterly wins during the
afternoon at 20-25kts. Decided to add FWZs 430 and 431 in a
Fire Weather Watch to be on the safe side for Sunday. Continued
warm and dry through the sort term otherwise.

&&

.LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/...
Issued at 240 PM MDT Fri Apr 12 2024

A benign weather pattern turns cooler, wetter, and more unsettled
starting Monday and continuing through at least mid-week.

Monday a trough drops into Four Corners region and begins to wrap
moisture into southeast Wyoming and turn flow easterly. As
temperatures are still forecast to be in the 60s to 70s ahead of the
cold front, with the increased moisture, easterly upslope flow, and
a few hundred J/kg of CAPE, a few thunderstorms across the High
Plains is not out of question. Current long range model runs are
showing this low rapidly developing and closing off in southeast
Colorado Monday night/Tuesday morning and ejecting eastward,
followed by a very brief ridging ahead of the next low pressure
system dropping out of Canada. Tuesday as the low ejects eastward
there is still the potential for rain showers in the plains, but the
thunderstorm chance is lower. Wednesday is where models diverge
quite drastically in their solutions. Overall, long range models
seem to keep southeast Wyoming and western Nebraska in the warmer
temperatures for longer, decreasing the total snow amounts, but
keeping the rain chances around until Wednesday night, then
transitioning to snow. This transition is nearly 24 hours later than
what models were showing yesterday. Both the ECMWF and GFS have
continued to waffle back and forth in terms of both precipitation
amounts and warmer/colder temperatures. That being said, cluster
analysis is actually in somewhat close agreement more toward the
warmer temperatures, but total QPF amounts still vary by nearly
0.20+ inches across southeast Wyoming and western Nebraska. This
means, confidence is still low in terms of how cold temperatures
will drop, how much precipitation people will receive, and if that
precipitation will be rain or snow and when that transition will
happen. However, confidence is increasing that precipitation will be
mainly rain or a rain/snow mix until Wednesday.

&&

.AVIATION /00Z TAFS THROUGH 00Z SUNDAY/...
Issued at 1033 PM MDT Fri Apr 12 2024

VFR for TAFs through the forecast period. Winds will be mostly
VRB overnight for terminals, before rapidly picking up midday Saturday
morning. Wind gusts of 20-30 knots will be expected after 16z
for all terminals.

&&

.CYS WATCHES/WARNINGS/ADVISORIES...
WY...Fire Weather Watch from Sunday afternoon through Sunday
     evening for WYZ430-431.
NE...None.

&&

$$

UPDATE...GCC
SHORT TERM...GCC
LONG TERM...LEG
AVIATION...BW