FXUS65 KPIH 240807
AFDPIH

Area Forecast Discussion
National Weather Service Pocatello ID
207 AM MDT Mon Aug 24 2026

.KEY MESSAGES...

- Southern two-thirds of forecast area under marginal forecast
  for severe thunderstorms today and tonight. 

- Thunderstorms continue with less coverage today compared to
  yesterday. Slight chance of thunderstorms each day through 
  Sunday.

- Weak warming trend through Thursday, then a cooling trend to
  Sunday.

&&

.DISCUSSION...
Issued at 140 AM MDT Mon Aug 24 2026

Today through Wed night...The upper level ridge centered over 
the desert southwest will strengthen over the next couple of 
days. This will put temperatures on a very weak warming trend, 
but it will not stop moist and unstable air rotating through the
upper level southwest flow into southern Idaho. SPC has once 
again put the southern 2/3 of the forecast area in an area of 
marginal severe thunderstorm threat. Fortunately, this marginal 
threat is only expected to last through this evening. Weaker 
thunderstorms with lessening threat continues Tue through Thu, 
then beyond this the threat falls off even more. Wind outside of
thunderstorms should return to being light. 

Thu through Sun...As mentioned above, the trend is for less and
less thunderstorm activity, barely rating mentioning during this
period. However, on Thu this upper level ridge breaks down as
the coastal upper level low pushes onshore in southern Canada.
This movement causes the airflow to be more westerly and drier,
and the incoming low increases the gradient aloft as it makes
its closest approach on Thu, Fri, and Sat afternoons, when the 
stronger wind gets a chance to mix down to the surface. The
approach of this low also produces a cooling trend that starts
Thu afternoon to the end of the forecast period. 

&&

.AVIATION /06Z TAFS THROUGH 06Z TUESDAY/...
Issued at 1041 PM MDT Sun Aug 23 2026

Expect virga showers to remain south of TAF sites overnight. 
Most likely looking at convection once again Monday afternoon 
with 30% chance of storms at TAF locations. Gusty winds and 
brief heavy downpours reducing visibilities are main impacts.

&&

.FIRE WEATHER...
Issued at 140 AM MDT Mon Aug 24 2026

Upper level high pressure has built back in, but moist and
unstable air from the south continues to flow in. Except for the
Salmon-Challis NF and northern end of the Eastern Idaho Dispatch
center has a marginal risk of severe thunderstorms.
Thunderstorms should be mainly dry, and are also becoming more
isolated than scattered. Thus through Wed expect warming and
drying, with continued poor recovery in the central Idaho
mountains especially. 

Wind will calm down from the Sunday wind event, and stay below
critical thresholds through Wed. A low passing to the north,
centered in southern Canada, will kick up the wind on Thu, Fri,
and Sat afternoons. It also brings in cooler air, so what
exactly happens to the humidity readings is up in the air, but
there could be critical fire weather conditions for this period. 

&&

.PIH WATCHES/WARNINGS/ADVISORIES...
None.

&&

$$

DISCUSSION...Messick
AVIATION...13
FIRE WEATHER...Messick