Hail in Idaho, June 23, 2021

Area Forecast Discussion
National Weather Service Pocatello ID
220 PM MDT Wed Jun 23 2021

.SHORT TERM...Tonight through Friday night. Upper ridge continues
to deteriorate ahead of moisture surging north around low off
California coast. Cloud cover over eastern half of forecast area
through early afternoon has put a damper on development of
instability. Elsewhere and where clearing is starting to be
realized, satellite is showing convective buildups. Radar has a
few storms forming over northern Nevada, which should be the
beginning of the activity expected in East Idaho for the rest of
today. Moving into Thursday, precipitable waters are on the
increase as additional moisture continues to surge into the
region. Thunderstorm chances spread across more of the region, and
better coverage is expected even though shear profiles are
relatively unimpressive this time of year. Friday, convective
potential is limited to eastern highlands, with isolated coverage
for other higher elevation areas. This should be the last gasp of
precipitation potential before we start to see the heat effects of
the building high pressure for next week. DMH

.LONG TERM...Saturday through next Wednesday. Very anomalous high
pressure settling into the Pacific NW will build into the area. With
high as strong as it is, the period is expected to be precipitation
free. But the big story continues to be the excessive heat
associated with the high. Models remain consistent with each other
and with previous runs in their depiction of this potentially historic
heat wave. Some daily max temp records are sure to fall Monday
through Wednesday, but some all time records will probably be
broken as well. Temperatures will remain well above normal through
the end of next week and into the Independence Day weekend. Heat
advisories and excessive heat watches/warnings will likely be
needed Monday through Wednesday. Crawford

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.AVIATION...Cloud cover over SE Idaho has slowed down
destabilization there. Because of this, I took VCTS out of the
eastern TAFs. There is still an outside chance of convection
developing to the point of isolated CBs there, but better chances
are farther west...especially south and west of the TAFS. Left the
mentions in BYI and SUN. CAMs show better chances of scattered
convection in the central mountains tomorrow than today, so included
the VCTS both today and tomorrow for SUN.
Crawford

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.FIRE WEATHER...Cloud cover through the early half of the day has
limited thunderstorm development so far for southeast Idaho.
Satellite and radar is starting to show some development in
northern Nevada, indicating better potential this afternoon and
evening for the southern Sawtooth. Will let the Red Flag Warning
stand as is for now, with the caveat that the coverage may be more
isolated for 413 than previously expected. As moisture continues
to pool in the Great Basin and works north tomorrow, thunderstorm
coverage increases. Another Red Flag Warning may be necessary for
thunderstorm coverage for Thursday. These storms should
transition toward producing wetting rains. Isolated storms
continue most higher elevations Friday, with best chances along
the Wyoming border. Beyond that, expect temperatures to trend
hotter through the weekend into next week. Humidities drop as well
as we trend into an exceptionally hot pattern that could threaten
record heat for many areas of East Idaho. DMH

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.PIH WATCHES/WARNINGS/ADVISORIES...
Red Flag Warning until 9 PM MDT this evening for IDZ413-427.

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