Area Forecast Discussion
Issued by NWS Riverton, WY

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000
FXUS65 KRIW 202019
AFDRIW

Area Forecast Discussion
National Weather Service Riverton WY
219 PM MDT TUE SEP 20 2016

.Short Term...tonight Through Wednesday

Breezy to windy conditions will increase tonight and Wednesday
as a large Pacific low pressure trough moves inland.  Moisture
will increase in the flow Wednesday with scattered showers and
isolated thunderstorms developing over the west by the afternoon.
Temperatures will fall in the west and north through the day.

.Long Term...Wednesday Night Through Tuesday

Showers will become widespread with embedded thunderstorms
Wednesday night through Thursday as temperatures fall rapidly.
A colder wetter period will continue through Friday. Snowfall is
expected to be limited to the mountains above 9500 feet. Friday
night the closed upper level low is expected to move northeast
from southwest Wyoming into central Wyoming which is not the most
favorable location for much of the area. Precipitation is shifted
north and east with decreasing precipitation central and south.
Precipitation will be spottier on Saturday with the cold pool
centered over the area. North flow will develop Saturday night and
Sunday with drying. Cold high pressure will be over the area
Sunday night and Monday then a warming trend will occur through
Tuesday.

&&

.Aviation.../00Z Issuance/

Conditions will be VFR through 00Z/Thursday. West to southwest wind
of 10-20kts this afternoon will diminish by 02Z/Wed leaving winds
less than 10kts overnight. The exceptions will be KCPR where
southwest wind will stay around 10kts through the night, and at KRIW
where northwest downvalley wind will blow around 12kts into early
Wednesday morning. Upper-level flow will back more to the southwest
on Wednesday. Moisture associated with Tropical Storm Paine will
remain to our south, but moisture ahead of a trough in the Pacific
Northwest will push into western Wyoming by 00Z/Thu. Have included
VCSH Wednesday afternoon at KJAC and KBPI. East of the Divide, a
cold front will push into the northern Big Horn Basin during the
morning with a stronger push during the afternoon. Gusty north wind
at KCOD during the afternoon, as a result, along with developing
VCSH. Cold frontal passage will also switch the wind to the
northwest at KWRL late in the afternoon. Pressure gradient will keep
wind out of the south or southeast across central and southern
terminals Wednesday afternoon.

&&

.Fire Weather...

Breezy to windy conditions will increase tonight and Wednesday
as a large Pacific low pressure trough moves inland.  Moisture
will increase in the flow Wednesday with scattered showers and
isolated thunderstorms developing over the west by the
afternoon. Showers will become widespread with embedded
thunderstorms through Thursday as temperatures fall rapidly. A
colder wetter period will continue through Friday.

&&

.RIW Watches/Warnings/Advisories...
Red Flag Warning until 8 PM MDT this evening for WYZ280-289.

&&

$$

SHORT TERM...C.Baker
LONG TERM...C.Baker
AVIATION...CNJ
FIRE WEATHER...C.Baker



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