297 
FXUS65 KRIW 290547
AFDRIW

Area Forecast Discussion
National Weather Service Riverton WY
1047 PM MST Mon Jan 28 2019

.SHORT TERM...(Tonight through Tuesday night)

Clouds and lingering flurries were diminishing across the I-25 
corridor and the southwest Big Horn Basin late this afternoon.
Cold, northwest flow will remain and gusty northwest 25 to 35 mph
will continue along the I-90 corridor through sunset. Although
areas of blowing snow will continue until sunset, believe impacts
are localized so the winter weather advisory will expire at 2 PM 
Monday. These wind speeds will decrease tonight but 12 to 25 mph 
winds are likely to prevail in northern Johnson County tonight. 
The clearing sky and fresh snow cover will allow for good 
radiational cooling, particularly in the basins and valleys where
winds will be calm. Therefore, temperatures will be below normal 
Monday night with most areas in the single digits above and below 
zero. Wind chill readings look to remain above highlight criteria 
with advisories not necessary. Nonetheless, wind chill readings 
will be below zero in northern Johnson County. Plenty of sunshine
in store for Tuesday but the cold start to the day will limit 
daytime temperature recovery. Maximum temperatures will be 10-15F 
below normal Tuesday. Following a cold day Tuesday with another 
clear sky overnight, temperatures Tuesday night will be as cold if
not colder than those of Monday night. The lingering brisk 
northwest wind over northern Johnson County will finally diminish 
Tuesday evening. Southwest surface wind will increase to 10 to 20 
mph late Tuesday night in the wind corridor from eastern 
Sweetwater to Natrona County with temperatures possibly climbing
in those areas toward sunrise Wednesday.

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

Conditions will be dry and cold over the forecast area, as NW flow 
aloft continues. Temperatures will begin to moderate over the 
forecast area by Thursday. The pattern will begin to shift Friday, 
as the ridge that was over the western CONUS shifts eastward over 
the Plains. This will turn the flow aloft more west-southwest. 
Conditions will remain dry through Friday, as moisture ahead of the 
next weather system begins to spread into western WY Friday night. 
Saturday and Sunday are going to be unsettled over the region. On 
Saturday, the best chance of snow will be in the west and southwest 
with dry conditions elsewhere. High temps will be slightly cooler, 
but still mild to begin February. Sunday and Sunday night look like 
a snowy period for the mountains, with scattered snow at the lower 
elevations as a weather system moves through the area. Guidance 
continues to evolve for Sunday, but it remains to look unsettled 
over the forecast area. As a result, high temps will be colder on 
Sunday. Next Monday is shaping up to be cold, with some snow for 
parts of the area. 

&&

.AVIATION...(For the 06Z TAFS through 06Z Tuesday night)
Issued at 1046 PM MST Mon Jan 28 2019

Patchy morning fog is possible in valleys and basins with the best 
shot across the Upper Green River Basin. Otherwise, VFR conditions 
are expected with SKC to some mid/high level clouds at times. There 
is a better fog signature for Tuesday night with a steep surface 
inversion along with a very dry layer just above the boundary layer. 
However will not include any fog for Tuesday night for now. The 
other concern could be marginal low-level wind shear at KCOD Tuesday 
night. 

&&

.FIRE WEATHER...

Lingering clouds and flurries across central Wyoming will come to an 
end early Monday evening with a mostly clear sky to follow. Cold, 
northwest flow aloft will remain across much of the region through 
Wednesday. Temperatures Tuesday and Wednesday will be below normal,
although temperatures will warm at least a few degrees Wednesday.
Gusty northwest surface wind of 15 to 30 mph will continue 
Tuesday along the I-90 corridor. The surface wind will switch to 
the southwest Wednesday favoring the wind corridor from eastern 
Sweetwater through Natrona County. A ridge of high pressure will 
then make its way across the region late in the week. Overall, 
conditions will remain dry through Friday before a better chance 
of precipitation this coming weekend. Smoke dispersal will be poor
to at best fair across most lower elevation locations, especially
the basins and western valleys.

&&

.RIW WATCHES/WARNINGS/ADVISORIES...NONE.

&&

$$

SHORT TERM...MH/CNJ
LONG TERM...TL
AVIATION...Murrell
FIRE WEATHER...CNJ