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Area Forecast Discussion (AFD)

Issued by Cheyenne, WY (CYS)

FXUS65 KCYS 130443

Area Forecast Discussion
National Weather Service Cheyenne WY
1043 PM MDT Thu Sep 12 2019

Issued at 718 PM MDT Thu Sep 12 2019

Looking at the 18Z model suite...looks like a windy day Saturday
with 700mb winds 30-35kts. We were close to critical fire weather
conditions with lower wind speeds already...but with these higher
winds...thinking critical fire weather conditions are going to be
almost certain. Decided to issue a Fire Weather Watch for much of
southeast Wyoming Saturday. Updates have been sent.


.SHORT TERM...(This evening through Friday night)
Issued at 235 PM MDT Thu Sep 12 2019

The low pressure system that was associated with yesterday's cold
front continues to spin over central South Dakota as seen on
satellite imagery bringing cloud cover to northern portions of 
the CWA, especially across Dawes County, NE. A few light rain 
showers are possible this afternoon across these areas before the 
low pushes farther toward the east. Additionally, gusty winds out
of the northwest will continue across the region until early 
evening Thursday as the surface low continues to move out of the 
region. Most areas east of the Laramie Range are recording wind 
gusts around 35 mph while the northern Nebraska Panhandle has seen
a few gusts 45 to 55 mph.

Skies will continue to clear up into overnight Thursday as a zonal
flow pattern begins to settle in. Overnight lows across the plains
will be in the 40s while the mountains could dip into the 30s.
Highest peaks, especially in the Snowys, could see temperatures
below freezing. A warming trend will begin Friday headed into the
weekend as our drying pattern continues. Afternoon temperatures
will be in the mid-70s, the climatological normal for mid-
September across our area. 

.LONG TERM...(Saturday through Thursday) 
Issued at 235 PM MDT Thu Sep 12 2019

Saturday and Sunday will be the driest days over the next stretch.
700 mb temperatures will warm up reaching 10 to 15 C this weekend
resulting in RH values down into the teens both days across much 
of Carbon and Albany Counties in Wyoming. Winds gusts will be 
right at or just below Red Flag criteria. Will need to monitor 
future model trends to determine if fire weather headlines will be
needed this weekend. 

The next best chance for precipitation across the region will be
Tuesday and Wednesday of next week. A deep upper level trough will
move ashore pushing a few disturbances through the region. There
is still some disagreement between the 12Z GFS and Euro on the
timing and progression of this upper level trough. However,
showers and thunderstorms will still be possible early- to mid-


.AVIATION...(For the 06Z TAFS through 06Z Friday night)
Issued at 1042 PM MDT Thu Sep 12 2019

VFR conditions through the next 24 hours and beyond. Gusty winds 
return Friday...though less than what we experienced Thursday.


Issued at 235 PM MDT Thu Sep 12 2019

Windy conditions will continue across much of the region, 
especially across the northern Nebraska Panhandle through early 
evening Thursday. Most locations east of the Laramie Range are 
gusting to 35 mph with gusts in Dawes County, NE near 55 mph. 
However, cooler temperatures and some cloud cover has kept RH 
values higher in the wake of yesterday's cold front. Temperatures 
will begin to warm up heading into the weekend along with lower 
humidities. Saturday and Sunday could be a concern for Red Flag 
conditions as RH values drop into the teens west of the Laramie 
Range and wind gusts will be approaching Red Flag criteria. 
Relatively dry conditions will continue ahead of our next best 
chance for wetting rains on Tuesday and Wednesday.


WY...Fire Weather Watch from Saturday morning through Saturday 
     evening for WYZ301-303-304-306-308>310.