586
FXUS65 KCYS 170409
AFDCYS

Area Forecast Discussion
National Weather Service Cheyenne WY
1009 PM MDT Thu May 16 2024

.KEY MESSAGES...

- Warm & dry conditions prevail through Saturday. Daytime highs
  on Friday may reach the lower to middle 80s for areas along
  and east of I-25.

- Windy on Friday as a strong disturbance tracks across the
  northern high plains. A couple brief gusts in excess of 60
  MPH cannot be ruled out.

&&

.SHORT TERM /THROUGH SATURDAY NIGHT/...
Issued at 315 PM MDT Thu May 16 2024

Warm and dry weather is expected through most of Saturday as a
warming trend continues through Friday. Current observations
across the area show scattered mid to high clouds with
temperatures well into the 70s for most locations, with mid to
upper 60s west of I-25. Expect temperatures to trend warmer over
the next 24 hours as a flattened ridge axis quickly moves east
across the Front Range tonight. Overnight low temperatures
tonight will be milder compared to last night as the thermal
ridge axis at 700mb begins to extend northeast into southeast
Wyoming and far western Nebraska. Overnight lows should bottom
out in the mid 40s to low 50s tonight with the high valleys
closer to the mid to upper 30s.

A warm and pleasant day expected on Friday with highs in the mid
70s to mid 80s as 700mb temperatures climb above 10 degrees. A
few locations across western Nebraska may approach 90 degrees.
Winds aloft will increase through the day along with surface
pressure gradients near a surface cold front to the west, so
expected breezy conditions along and east of the I-25 corridor,
with windy conditions for Rawlins, Laramie, and Elk Mountain and
vicinity. Will have to watch for locally higher gusts around 55
MPH from mid Friday afternoon through Friday night as 700mb
flow peaks at 45-50 knots. Models have trended a little higher
with these winds compared to the last several runs, so will have
to monitor this trend for High Wind headlines. As of right now,
looks like a low end event with probability of wind gusts over
48 knots of 25 percent or less for most of southeast Wyoming.

Temperatures will be a little cooler on Saturday behind the weak
cold front. Models in better agreement with this initial cold
front compared to earlier this week, showing the bulk of the
cold air remaining well to the north across northern Wyoming and
Montana. Therefore, only a slight decrease in temperatures is
expected with highs in the low to mid 70s with breezy conditions
and west to southwest winds gusting up to 35 MPH at times west
of I-25. As the cold front stalls across Colorado and weakens, a
few showers and thunderstorms may form in the afternoon and push
northeast towards the I-80 corridor through the evening hours.
Kept POP between 15 to 25 percent for widely scattered showers
and thunderstorms...mainly south of the North Platte River
valley.

&&

.LONG TERM /SUNDAY THROUGH THURSDAY/...
Issued at 242 PM MDT Thu May 16 2024

The medium range to long term forecast includes an active weather
pattern and near to slightly below normal temperatures. Multiple
shortwave disturbances will eject out of the Pacific northwest over
the course of the next. Unfortunately, there will be a couple of
strong cold fronts on the horizon, so the potential for snow showers
in the higher terrain still remains for the third week of May.

A positively tilted upper level trough will swing out of the
Canadian Rockies toward the Great Basin early Sunday. We will have
enough diurnal heating, moisture, and lift for isolated showers and
thunderstorms to increase in coverage by late Sunday afternoon.
Daytime highs in the 70s to low 80s for areas east of the Laramie
Range, and slightly cooler west of the Laramie Range can be
expected.

Models are progged to bring a cold front through the region on
Monday, with the GFS being the most aggressive. Have nudged daytime
highs down a degree or two in response to this, with the potential
to continue the trend if model consistency proves true for the
coming days. Have gone against the deterministic forecast for the
GFS, which would bring temperatures down into the 30s for our
western zones by sunset of Monday evening. This would bring an
uptick in the chance of snow showers for those western forecast
areas.

Tuesday through Thursday brings additional chances of showers and
thunderstorms, but model consistency with respect to location
remains low. Daytime highs will slowly rebound for most areas
between Tuesday and Thursday, but the persistent cloud cover and the
chance of rain and thunderstorms will limit daytime sunshine. Expect
daytime highs in the 50s for Tuesday, with 60s to mid 70s becoming
more widespread for Wednesday and Thursday.

&&

.AVIATION /06Z TAFS THROUGH 06Z SATURDAY/...
Issued at 1003 PM MDT Thu May 16 2024

Northwest flow aloft this evening will become west Friday, and
continue through the period. A cold front will enter southeast
Wyoming Friday evening. Scattered clouds around 15000 feet will
prevail. Winds will gust to 28 knots at Rawlins until 08Z, and
from 22 to 38 knots at all terminals from 14Z to 01Z.

&&

.CYS WATCHES/WARNINGS/ADVISORIES...
WY...None.
NE...None.

&&

$$

SHORT TERM...TJT
LONG TERM...BW
AVIATION...RUBIN