Area Forecast Discussion
Issued by NWS Cheyenne, WY

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FXUS65 KCYS 222044

Area Forecast Discussion
National Weather Service Cheyenne WY
244 PM MDT Sat Oct 22 2016

.SHORT TERM...(This evening through Monday night)
Issued at 224 PM MDT Sat Oct 22 2016

The warm and dry weather looks to hold across the CWA for the
most part through Monday as an upper ridge passes across Sunday
and Sunday night. Some breezy conditions again Sunday afternoon
over the western valleys but nothing too strong. Skies expected to
be mostly clear through Sunday with just some high clouds at
times. Small changes begin on Monday as the departing upper ridge
leaves a southwesterly flow in its wake. Moisture will begin
increasing over the area Monday ahead of an upper trough that will
move into the western CONUS. Some showers look to spread into
mainly Carbon county Monday afternoon and continue into Monday
evening as weak impulses begin lifting northeast over that area.

.LONG TERM...(Tuesday through Saturday)
Issued at 224 PM MDT Sat Oct 22 2016

The main concern with this portion of the forecast is the timing
of the shortwave features moving ahead of the Eastern Pacific
trof next week.

Tuesday-Tuesday night:
The models are in pretty good agreement with bringing the initial
shortwave through the forecast area on Tuesday into Tuesday
evening. This system appears to bring some moisture along with it,
but it appears like the bulk of the moisture will impact the
mountains. However, it does not look like a snow maker due to this
wave tracking to the north of the area leaving us on the warm side
of the shortwave. It may become a bit breezy after this shortwave
passes through on Tuesday, but we are not looking at any high
impact winds at this time.

Another period of nice weather is setting up during the remainder
of the week in response to a strong upper level ridge building over
the area. The fire danger may be a bit on Thursday due to strong
subsidence along with some gusty winds mainly west of the Laramie
Range. Otherwise, the next shortwave of concern will be on Friday
night or Saturday. Once again, the bulk of the shortwave energy
should stay to our north which will limit any big cool down. The
best chance of precipitation should be across the mountains and
the higher elevations in Wyoming.


.AVIATION...(For the 18Z TAFS through 18Z Sunday afternoon)
Issued at 1129 AM MDT Sat Oct 22 2016

The main concern with this taf issuance is the timing of the weak
frontal boundary moving through the area tonight.

Latest water vapor loop was showing a shortwave moving through
northern Montana. Latest surface analysis was showing low
pressure in northeast Wyoming with an associated frontal boundary
near the Wyoming/Montana border. As this shortwave scoots across
towards the northern plains, we should see this frontal boundary
push southeast this evening. At this point, it appears like this
boundary will move through KCDR around 02z, KAIA around 04z, and
KCYS around 08z. Not seeing much wind behind this boundary.
However, we will have to keep an eye on how this boundary evolves
this evening. Otherwise, the wind will be gusty this afternoon
across most sites except for KBFF where they may take a little
while to mix out.


Issued at 224 PM MDT Sat Oct 22 2016

Fire weather concerns will decrease once the current critical
conditions come to an end by this evening. A trend towards a
little cooler temperatures and increased moisture is expected
Sunday into early next week. Some showers are expected Monday
night into Tuesday in association with a passing disturbance.


WY...Red Flag Warning until 6 PM MDT this evening for WYZ301-302-309-

NE...Red Flag Warning until 6 PM MDT this evening for NEZ311>313.



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