486
FXUS65 KRIW 111122
AFDRIW

Area Forecast Discussion
National Weather Service Riverton WY
522 AM MDT Thu Jul 11 2024

.KEY MESSAGES...

- Temperatures rise again today. Hot conditions will be widespread
  this afternoon.

- A few showers may bring strong outflow winds today with the best
  chances east of the Continental Divide.

- Temperatures remain hot through the weekend, then cool
  slightly for early next week.

&&

.DISCUSSION...
Issued at 412 AM MDT Thu Jul 11 2024

Heat will continue to be the leading concern through the upcoming
weekend. The strong ridge remains in place, currently centered over
the southern Great Basin. This will help 700mb temperatures reach
into the 18 to 21C range today. Accordingly, we`ll be even warmer
this afternoon than the previous few days, with highs in the upper
90s to low 100s east of the Divide and low to mid 90s west. That`s
good for around 10 degrees warmer than normal for this time of year.
Other than the heat, we`ll still likely see some cumulus buildup and
a few showers again today owing to weak divergence aloft rotating
through as well as decent moisture availability east of the Divide.
Like yesterday, most of the activity will be in the form of virga
showers, and the main concern will be strong outflow winds given the
deeply mixed boundary layer.

There will not be much change in the pattern for the next few days.
The center of high pressure will very slowly shift eastward, still
keeping 700mb temperatures around 18 to 21C. This will keep the heat
going across the area, with continued low shower chances mainly east
of the Divide. Given the warm and overall dry conditions at the
surface, fire weather concerns will be heightened, though mitigated
by wind remaining on the lighter side. Still, there are some
indications of wind increasing enough Friday and Saturday afternoon
that we may soon need to consider fire weather highlights if trends
hold.

Models are still hinting at some sort of shortwave approaching on
Sunday, though the timing of this feature will determine whether or
not this will break the heat or not Sunday afternoon. Currently,
Sunday is looking just as hot, with the forecast instead reflecting
better shower coverage during the afternoon and evening. By early
next week the ridge does appear to break down somewhat according to
most solutions. This would bring highs down to near normal, and also
introduce more convection as a couple of waves move through the now
weaker ridging.

Further out, ensemble cluster guidance favors continued anomalously
high 500mb heights over Wyoming through next week. This would keep
temperatures on the warm side and precipitation chances generally
low.

&&

.AVIATION /12Z TAFS THROUGH 12Z FRIDAY/...
Issued at 516 AM MDT Thu Jul 11 2024

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

Prevailing VFR conditions persist through the TAF period. Wind will
increase by about mid-afternoon today and decrease around sunset.
Wind will be sustained in the low teens, with gusts around 20 knots.
Skies will remain mostly clear, although mid-level scattered cumulus
will develop in the afternoon. Thermals will be quite strong
Thursday afternoon.

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

Prevailing VFR conditions persist through the TAF period. Wind will
increase by about mid-afternoon Thursday and decrease around sunset.
Wind will be sustained in the low teens, with gusts around 20 knots.
Another afternoon of isolated convection will occur Thursday on the
periphery of the ridge as it takes its sweet time moving north and
east. Lingering showers are possible (30%) into Thursday evening
around KCPR and KCOD. Similar to Wednesday, numerous outflow
boundaries are likely (70%) in the afternoon as downdrafts from
convection develop. This will lead to gusty erratic wind at times
through Thursday afternoon/into the evening hours. Thermals will be
quite strong Thursday afternoon.

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

&&

.RIW WATCHES/WARNINGS/ADVISORIES...
Heat Advisory from noon today to 10 PM MDT Sunday for
WYZ004>006-010-011-017-018-020.

&&

$$

DISCUSSION...Myers
AVIATION...Rowe/Swanson