239
FXUS65 KBOI 030311
AFDBOI

Area Forecast Discussion
National Weather Service Boise ID
911 PM MDT Wed Jul 2 2025

.DISCUSSION...Thunderstorms remain active across portions of the
region this evening, driven by an upper level shortwave moving
through the area. As of 8:30 PM MDT, a cluster of storms
extends from Malheur County through the Treasure Valley and into
the West Central Mountains of Idaho. These storms have generated
multiple outflow boundaries, producing wind gusts up to 45 MPH
along with areas of blowing dust.

While the strongest winds gusts were observed earlier in the
evening, gusty winds remain a concern as storms continue to move
through the region. LSRBOI as details of reported winds so far
for this event. With the loss of daytime heating, storm
intensity is expected to gradually decrease, and any additional
gusts should be in the 35-45 mph range. However, isolated
stronger gusts remain possible near collapsing storm cells or
along well-developed outflow boundaries.

The forecast has been updated this evening to reflect the
ongoing thunderstorm coverage across southwest Idaho. Showers
and thunderstorms activity will gradually diminish through the
late evening hours, but a few lingering storms may persist into
the overnight period, particularly in the West Central
Mountains of Idaho.

&&

.AVIATION...Mostly VFR. Scattered showers/thunderstorms through
03/06z tonight, creating erratic gusts to 30-45 kt, small hail,
and blowing dust. Numerous showers/thunderstorms with 30-45 kt
gusts return Thu afternoon through Fri. Mtn obscuration and
localized MVFR visibility with storms. Surface winds outside of
storms: SW-NW 5-15 kt with 20-30 kt gusts this eve, becoming
variable 5-15 kt overnight. Winds aloft at 10kft MSL: WSW 10-20
kt.

KBOI...VFR. Erratic outflow boundaries 25-35 kt tonight due to
surrounding showers/thunderstorms this eve, calming overnight.
Showers/thunderstorms returning Thu evening into Fri, with erratic
outflow winds 30-45 kt, lightning, reduced visibility in rain.
Surface winds outside of storms: NW-W 5-15 kt.

&&

.PREV DISCUSSION...
SHORT TERM...Tonight through Friday night...An upper-level
shortwave trough has made its way into SE Oregon this
afternoon. Thunderstorms are ongoing and forming across much of
SE Oregon and parts of SW Idaho. Satellite reveals widespread
cumulus development over the past two hours leading up to this
as well as continued robust development. A Red Flag Warning
remains in effect today for the likelihood of scattered
lightning over much of eastern Oregon. In addition, an Heat
Advisory is in effect for the Lower Treasure Valley of Oregon
through tonight. Although temperatures will be a few degrees
less hot compared to yesterday, the relative humidity will be
higher, resulting in similar heat risk. Mesoscale models have
decreased coverage over the past few runs, however, forecaster
confidence has remained. The primary threats are damaging wind
gusts, with gusts up to 40-50 kts possible, and small hail.
DCAPE values of near 1300 J/kg are becoming widespread as 20Z,
with local maxima of 1600 J/kg or greater being forecast. With
these values, strong wind gusts are certainly possible if storms
can capitalize on the CAPE values near 500 J/kg.

Thursday morning into afternoon will be quiet before a strong
upper-level shortwave trough moves into the area
evening/overnight Thursday into Friday. Precipitation chances
will increase as this moves in, with moisture values and
temperatures sufficient to threaten thunderstorms again for both
days. DCAPE values and temperatures will be lower on both days.
The threats are mainly focused close to the NV border Thursday
evening, increasing to become widespread Friday.Our current
thinking is that we may see significant storms late Thursday
night extending right on into Friday morning and through the day
Friday. The trough is notably stronger than the one we will see
today, but thermodynamic parameters will be weaker.

LONG TERM...Saturday through Wednesday...As the upper-level
trough that impacted the region Friday moves east, another
upper-level trough will stall out over the coast of California
over the long term period. As this happens, a strong upper-level
ridge will build in over the Desert Southwest and Great Basin.
Dry southwesterly flow will envelop SE Oregon and SW Idaho. This
will lead to a steady increase in temperatures Saturday through
Wednesday. Disagreement among long range models is high on how
the upper-level low off the coast of California will progress,
whether it rides the ridge or otherwise, however, the ridging
is well agreed upon. Temperatures will begin around 5 degrees
below normal Saturday, near normal Sunday, 5 degrees above
normal Monday, and around 10 degrees above normal Tuesday and
Wednesday. Lower elevation locations may experience 100 degrees
starting Monday (10-20% chance), with higher chances of reaching
100 degrees Tuesday and Wednesday (30-60% chance).

&&

.BOI WATCHES/WARNINGS/ADVISORIES...
ID...None.
OR...Red Flag Warning until midnight MDT /11 PM PDT/ tonight
     ORZ670-672>675.
     Red Flag Warning from 2 PM to 8 PM PDT Thursday ORZ670-672.

&&

$$

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DISCUSSION...JDS
AVIATION.....SH
SHORT TERM...CH
LONG TERM....CH