000
FXUS65 KRIW 120754
AFDRIW

Area Forecast Discussion
National Weather Service Riverton WY
154 AM MDT Fri Apr 12 2024

.KEY MESSAGES...

- Warm temperatures are expected across the state today with
  some areas seeing near record highs.

- Breezy conditions develop today and continue through the
  weekend with parts of Fremont, Natrona, and Sweetwater County
  seeing the strongest of winds.

- Isolated showers and a few thunderstorms are possible this afternoon/evening
  with the best chance being in NW WY.

- A return to below normal temperatures and unsettled weather is
  looking possible for next week.

&&

.DISCUSSION...
Issued at 153 AM MDT Fri Apr 12 2024

The rollercoaster of spring weather continues across the Cowboy
State. An example of this can be seen by looking at last weekends
weather, which was unsettled with below normal temperatures. This
weekend looks to be nearly opposite of that, with well above normal
temperatures and dry conditions. A potent ridge of high pressure
built in over the western CONUS yesterday and will continue to
gradually move eastward today. This ridge will be responsible for
the pleasant and mostly quiet weather over the next few days.

The next few days will remain mostly dry due to this ridging, with
the only exception being this afternoon/evening. A weak shortwave
will attempt to cut across the ridging during the afternoon and
evening. This quick moving and weak shortwave will allow for very
isolated showers and possibly thunderstorms to develop across the
CWA. The best chance (10-20%) for thunderstorms will be across NW WY
with the remainder of the state being around 5%. The atmosphere is
going to be very dry, which may lead to mainly virga showers and
isolated strong outflow winds.

Overall, the weather will remain analogous for the next few days
with some components worth discussing. The first is temperatures,
which look to be nearly 15 to 20 degrees above normal, with some
areas nearing record highs especially east of the Divide. Highs for
today are forecast to be in the mid 50s to mid 60s west of the
Divide and in the low to mid 70s east of the Divide. These warm
temperatures continue through the weekend, with cooler but still
above normal temperatures expected by Monday. Winds look to become
breezy over the next few days, with much of the state seeing light
10 to 20 mph winds. Natrona and Sweetwater Counties have a better
chance (40-60%) of seeing stronger gusts near 30 mph for Friday and
Saturday. The strongest winds arrive Sunday, as gradients tighten
and southwesterly flow increases due to a nearing Pacific
disturbance moving south of the CWA. Southwesterly flow favored
areas in parts of Natrona, Fremont, and Sweetwater Counties likely
(30-60%) see the strongest winds, with gusts of 40+ mph at times.
Other parts of the state have a good chance (50-80%) of seeing some
breezy conditions Sunday, with gusts of 20 to 30 mph. The last
component to note will be the dry RH values that look to stagnate
across parts of Sweetwater, Natrona, and Fremont Counties. RH values
are currently forecast to remain rather dry, ranging from 15-20%
Friday through Sunday. The reason this may be of concern, is with
the combination of warm temperatures and breezy winds elevated fire
weather conditions will be possible over these areas for the next
few days. Sunday looks to be the worst day, with gusts near 40 mph
for these areas, its very possible near critical fire weather
conditions may develop.

As mentioned earlier, spring weather is like a rollercoaster and
after a pleasant and warm weekend, change is inevitable. Next week
is still up in the air, with a lot of uncertainty regarding the
forecast. There looks to be two main disturbances that move through
the region over the course of the week. The first is the afore
mentioned Pacific disturbance that looks stay mainly to the south.
Impacts from this system look to remain minimal, with scattered
showers possible Monday afternoon through Tuesday morning. By
Tuesday morning this system will quickly slingshot towards the Great
Plains, as a potent Canadian disturbance barrels south from western
Canada. This second system has the best chance of bringing
widespread precipitation and below normal temperatures to the
region. However, what happens between these two systems is still
highly uncertain. There are two scenarios that models are showing,
one with widespread impacts to the CWA and the other having little
to no impacts. The first scenario has the Canadian system move south
into the Rockies with little to no interaction with the Pacific
system. This would bring widespread precipitation and below normal
temperatures to the region, along with chance for accumulating snow.
The other scenario has the Canadian system remain to the north and
absorb the Pacific system, creating a large potent upper-level low
over the Northern Plains. This would bring very minimal impacts to
the state, with any precipitation being limited to the northern part
of the CWA. Overall, a return to below normal temperatures and the
development of an unsettled pattern look possible but even being
less than a week away, uncertainty remains high.

&&

.AVIATION /06Z TAFS THROUGH 06Z SATURDAY/...
Issued at 853 PM MDT Thu Apr 11 2024

VFR conditions expected throughout the period for all TAF sites
under the influence of northwest flow aloft and surface high
pressure to the west. Light winds less than 10kts overnight into
early Friday morning under mainly clear skies. Increasing winds
after 16-19Z due to daytime heating and mixing to the surface.
Increasing high clouds throughout the afternoon with a subtle
shortwave passing later Friday evening. Winds will decrease
towards sunset after about 00-01Z becoming less than 10kts once
again. No impacts to any TAF sites with no other weather
elements expected at this time.


Please see the Aviation Weather Center and/or CWSU ZDV and ZLC for
the latest information on icing and turbulence forecasts.

&&

.RIW WATCHES/WARNINGS/ADVISORIES...
None.

&&

$$

DISCUSSION...Dziewaltowski
AVIATION...Lowe