424
FXUS65 KRIW 071031
AFDRIW

Area Forecast Discussion
National Weather Service Riverton WY
431 AM MDT Fri Jun 7 2024

.KEY MESSAGES...

- Above normal temperatures will continue the threat of rising
  rivers and minor flooding today.

- Isolated thunderstorms are possible today and Saturday, with a
  better chance of storms for Sunday and Monday.

- Drier and warmer weather is likely to return for the middle of
  next week.

&&

.DISCUSSION...
Issued at 242 AM MDT Fri Jun 7 2024

We have two main concerns with the weather this morning. The first
is the potential for convection and the second is for flooding
concerns. I will address the flooding in a separate hydrology
section.

Radar currently shows a few light showers across southwestern
Wyoming early this morning. These should not cause too much
impact. An approaching cold front, although a weak one, will
bring a chance for convection this afternoon and evening. There
is not a ton of moisture to work with, so coverage should be
fairly sparse and largely confined to the mountains (the chance
is less than 1 out of 4 in most locations). There is a concern
though with the threats. The Storm Prediction Center has put
southwestern portions of our area under a Marginal risk of
severe weather. With soundings showing the inverted V signature,
there could be strong wind gusts with any thunderstorm or even
an innocent looking shower, those infamous little green blobs.
This looks largely like a diurnal event, but a few showers could
linger in eastern Sweetwater County late tonight with some
upper level divergence from a weak right rear / left front jet
couplet. Otherwise, it looks like another warm to hot day with
our warmer spots likely taking another run at 90 degrees. Wind
will also be breezier than yesterday with the approaching front,
but high wind is not expected.

Saturday looks to be a slightly cooler day. There will be a few
showers and storms around again. Most guidance is focusing the
best coverage on southern portions of the area with a small jet
stream moving through the flow. The best chance of showers and
storms looks to be Sunday and Monday, as a deeper trough
approaches the area with more moisture. Placement of heaviest
precipitation is still in flux though. With more cloud cover,
temperatures look near to below normal through the these two
days.

Following that, most guidance of the deterministic and ensemble
varieties shows the ridge building back northward, bringing a
return of above normal temperatures and lesser chances of
precipitation. There could be a chance of a shortwave moving
through from time to time, but there is little model agreement
on this. The best chance would be across the north, but even
here most areas should stay dry on any given day. We made few
changes to continuity as a result.

&&

.AVIATION /12Z TAFS THROUGH 12Z SATURDAY/...
Issued at 430 AM MDT Fri Jun 7 2024

VFR conditions expected through the TAF period. Isolated
thunderstorms will be possible between 20Z and 02Z, with
northwestern and far southern portions having the better
chances. KJAC could be impacted between 00Z and 02Z. Winds with
gusts around 25 kt will increase between 16Z and 18Z across the
forecast area, decreasing between 02Z and 04Z. Higher winds due
to outflow boundaries could occur. A weak frontal boundary will
push southward across areas east of the Divide through the
afternoon, crossing the Divide and washing out by 04Z.

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

&&

.HYDROLOGY...
Issued at 242 AM MDT Fri Jun 7 2024

Another day of temperatures averaging 10 degrees above normal will
continue high elevation snowmelt will continue the trend of rising
rivers and minor flooding. We will continue the Flood
Advisories for Medicine Lodge Creek, Ten Sleep Creek and the
Popo Agie Rivers. Larger main stream rivers, especially the Wind
and Little Wind Rivers, are seeing rises and will have to be
monitored for possible rises today and into the weekend.

&&

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

&&

$$

DISCUSSION...Hattings
AVIATION...LaVoie
HYDROLOGY...Hattings