KCYS issues Area Forecast Discussion (AFD) valid 2019-12-06T10:01:00Z    

144

FXUS65 KCYS 061001

AFDCYS



Area Forecast Discussion

National Weather Service Cheyenne WY

301 AM MST Fri Dec 6 2019



.SHORT TERM...(Today through Sunday) 

Issued at 250 AM MST Fri Dec 6 2019



Pretty quiet weather expected today as a flattened upper level

ridge axis moves across Wyoming later in the day and into tonight.

The main story will be the fairly widespread fog east of

Interstate 25 this morning, mainly impacting far eastern Wyoming

and the western Nebraska panhandle. Visibility has been around one

half mile for most areas, but a few have observed locally dense

fog. Will continue a Special Weather Statement for these areas

into the early morning hours. Otherwise, expect daytime high

temperatures in the 40s for most locations.



Main forecast concern this weekend will be the potential for

strong winds as two Pacific troughs merge across the Front Range

as they push eastward this weekend. In-house models not quite as

favorable for a widespread high wind event, mainly due to the fact

that 00z models have trended lower with winds aloft, showing

700-600mb winds briefly around 50 to 55 knots. Low to midlevel

subsidence is still strong across the wind prone areas with some

strong winds possibly across the eastern High Plains. Kept the

High Wind Watch out for now, mainly due to low confidence in

timing since models have backed off quite a bit for late tonight

and early Saturday morning. The Pacific cold front, which is

forecast to push into the area on Sunday, will likely end the high

wind threat by noon on Sunday. Increased POP across the mountains

and areas north of I-80 for snow, or a rain/snow mix across the

lower elevations. 





.LONG TERM...(Sunday night through Thursday)

Issued at 230 AM MST Fri Dec 6 2019



Progressive upper trough passes across the CWA Sunday night/early

Monday bringing some snow showers and a cold front with it. Chilly 

Monday and Tuesday under nwly upper flow with a reinforcing surge

of cooler air dropping down the plains Tuesday with some flurries

possible with it. Milder Weds and Thursday but still on the cool 

side with a weak impulse passing by to the south early Thursday 

but looking to bring just an increase in clouds with it. 



&&



.AVIATION...(For the 12Z TAFS through 12Z Saturday morning)

Issued at 230 AM MST Fri Dec 6 2019



Areas of IFR/LIFR conditions due to low cigs and fog mainly over 

the Neb Panhandle will improve to VFR during the morning hours

with mainly VFR over the se Wy terminals, though patchy MVFR

conditions at KRWL. VFR then expected areawide this afternoon

and tonight with some gusty winds around the mtns tonight. 



&&



.FIRE WEATHER...

Issued at 219 AM MST Fri Dec 6 2019



No fire weather concerns through this weekend and into next week 

with recent widespread heavy snow and minimum daytime humidity 

values above 30-40 percent. Windy conditions are expected across

most of southeast Wyoming this weekend with locally strong winds

possible. 



&&



.CYS WATCHES/WARNINGS/ADVISORIES...



WY...High Wind Watch from this evening through Sunday morning for 

     WYZ106-110-116-117.



NE...None.

&&



$$



SHORT TERM...TJT

LONG TERM...RE

AVIATION...RE

FIRE WEATHER...TJT