000
FXUS65 KRIW 192006
AFDRIW

Area Forecast Discussion
National Weather Service Riverton WY
206 PM MDT Fri Apr 19 2024

.KEY MESSAGES...

- Below normal temperatures continue through tomorrow, although
  there will be more sunshine.

- Sunday looks substantially warmer with possible elevated fire
  weather.

- Although there will be a few chances for showers, no major
  storms are expected for the next 7 days.

&&

.DISCUSSION...
Issued at 203 PM MDT Fri Apr 19 2024

All in all today, looks like a carbon copy of yesterday. (For all
you young people out there, this is something we used for forms back
in the dark ages before computers were widespread. Wow I`m getting
old). Anyway, the main factor today is north to northeasterly flow
around an area of high pressure over southwestern Saskatchewan. With
some residual moisture and a bit of instability, we again had the
self destructive sunshine we talked about yesterday, with the a
stratocumulus deck developing in the mainly of the northeasterly
upslope locations and expanding outward. With this flow continuing
tonight, clouds may linger through the night. Otherwise, things are
tranquil with only a few snow showers in the favored areas with
little accumulation.

We should begin to transition into a more springlike pattern as
ridging begins to build into the area. Sunshine should be more
widespread on Saturday and this should allow temperatures to
moderate somewhat. It will still be on average 10 degrees cooler
than average, but at least the sunshine and light wind should make
it feel warmer. Sunday will be the significantly warmer day as we
go to the backside of the ridge and flow turns southwest, pushing
temperatures around 20 degrees warmer in most places. This will also
increase wind in the favored southwest flow locations, but mid level
wind does not look sufficient for high wind. It could bring elevated
fire weather to some locations Sunday afternoon though. Later in the
day, a trough and cold front will slide through the area and bring a
chance for showers, mainly to northwestern Wyoming. A few may linger
into Monday as well. The system is moisture starved though, so any
precipitation amounts would remain light, with less than 1 in 5
chance of a tenth of an inch in any location. The front will knock
temperatures down a bit on Monday, but only back to near seasonal
normals.

Flat ridging should then control the weather Tuesday through at
least Thursday, bringing near to above normal temperatures and
breezy conditions in some locations. A couple of shortwaves may
bring a few showers, but guidance is uncertain on the details. A
more complicated and more substantial scenario may be on tap for
next Friday into next weekend as a pair of upper level lows, one
moving across the United States-Canadian border and another moving
out of California into the Great Basin. How these would interact is
highly uncertain at this time, but there is greater than a 1 in 2
chance that Friday or next weekend looks unsettled and cooler.


&&

.AVIATION /18Z TAFS THROUGH 18Z SATURDAY/...
Issued at 1120 AM MDT Fri Apr 19 2024

West of the Divide...KBPI/KJAC/KPNA/KRKS Terminals.

VFR to prevail through the period. Gusty east-northeast surface wind
at KRKS slows for the afternoon and then increases to 15-25kts
tonight as surface high pressure slides south tightening the
pressure gradient. These speeds diminish just prior to sunrise
Saturday.

East of the Divide...KCOD/KCPR/KLND/KRIW/KWRL Terminals.

Lingering moisture in combination with jet dynamics has allowed for
low-end VFR and mid-cloud decks to persist across the Wind River and
Bighorn Basins late this morning. While ceilings rise this
afternoon, cloud cover is likely to remain through at least this
evening. Clouds dissipate around 12Z/Saturday as the moisture and
jet energy push east ahead of a shortwave in northwest flow aloft.
North to northeast surface wind will predominate for much of the
period. Mountain tops frequently obscured above 11K feet MSL.

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...Hattings
AVIATION...Jones