438
FXUS65 KBOI 270247
AFDBOI

Area Forecast Discussion
National Weather Service Boise ID
847 PM MDT Wed Jun 26 2024

.DISCUSSION...
Active convective episode is winding down across southwest Idaho
this evening with the loss of diurnal heating. A near record
amount of moisture for the date was observed in the BOI 00Z
sounding, which is also evidenced by the low-mid 60s dewpoints
throughout the Treasure Valley. In southeast Oregon, dry and
windy conditions are resulting in a near-critical fire weather
threat. A cold front is entering eastern Oregon and will bring
much drier air and cooler temperatures later this evening.
Thunderstorms may continue to develop along the front into the
west-central Mountains through the late evening. Otherwise, a
much quieter overnight period is expected as the dry air mass
overspreads the entire region into tomorrow.

&&

.AVIATION...Mostly VFR with mid/high level clouds, with isolated IFR
in thunderstorms across Idaho. Outflow gusts 30-50 kt, blowing dust
and hail possible. Storms will dissipate by Thu/06Z. Haze is
possible in SE Oregon due to smoke from wildfires. Surface winds:
Becoming W-NW 15-25 kt. Winds aloft at 10kft MSL: W-SW 15-30 kt.

KBOI...Mostly VFR with mid/high level clouds. Surface winds SE 5-15
kt, transitioning to NW later this evening. Cooler temps on Thursday
reduce high density altitude concerns.

&&

.PREV DISCUSSION...
SHORT TERM...Tonight through Friday night...Scattered showers
and thunderstorms continue to intensify with the afternoon
heating. A severe storm near Nyssa has caused significant wind
damage already and radar indicated 2" hail in the core of the
storm. Similar storms expected to form this afternoon, with the
peak heating of the day. With high temperatures in the mid 90s
in the lower valleys today, CAPE values reach 1000-1500 j/kg
this afternoon along with sufficient effective bulk shear
(30-40kts) for strong and organized thunderstorms. High
resolution guidance also shows storms with rotating updrafts
capable of up to 1-2" hail this afternoon. Main threat will be
wind gusts up to 50-60kts with significant DCAPE of 1500 j/kg,
and heavy rain. Some storms may produce ponding of water, as
storm motions will be 10-20kts. Severe storm threat will slowly
wind down this evening, but thunderstorm threat will continue
into the night over the central ID mountains. Drier air will
move in from the west by Thursday morning, with about 15 degrees
of cooling on Thursday afternoon compared to today`s highs.
Cool northwest flow will continue into Friday with temperatures
around 5 degrees below normal.

LONG TERM...Saturday through Wednesday...A shortwave ridge will
move over the area on Saturday, with temperatures rising back
into the mid 90s in the lower valleys. A trough off the Pacific
NW coast enhance the threat of showers and thunderstorms on
Saturday and Sunday. Westerly flow thereafter will keep
temperatures at or slightly above normal.

&&

.BOI WATCHES/WARNINGS/ADVISORIES...
ID...Red Flag Warning until 9 PM MDT this evening IDZ401-402.
OR...Red Flag Warning until 9 PM MDT /8 PM PDT/ this evening
     ORZ636-637.

&&

$$

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DISCUSSION...JR
AVIATION.....JM
SHORT TERM...KA
LONG TERM....KA