628
FXUS65 KBOI 261626
AFDBOI

Area Forecast Discussion
National Weather Service Boise ID
1026 AM MDT Wed Jun 26 2024

.DISCUSSION...Scattered showers and isolated thunderstorms
continue this morning across the area, ahead of a cold front
that will move through tonight. Some partial clearing expected
midday before scattered showers and thunderstorms intensify
with the afternoon heating. 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"
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. Current forecast on track with no updates.

&&

.AVIATION...VFR with mid/high level clouds. Isolated to scattered
showers/thunderstorms across SE Oregon and SW Idaho, continuing
through the afternoon. Outflow gusts 30-45 kt possible. Meanwhile,
hot daytime temperatures will increase density altitude today.
Surface winds: SE to SW 5-15 kt, increasing to 10-20 kt with gusts
to 25-30 kt in E Oregon and near NV/ID border this afternoon. Winds
aloft at 10kft MSL: SW 15-30 kt.

KBOI...VFR with mid/high level clouds. A 40% chance of
showers/thunderstorms hitting terminal between 26/18Z and 27/00Z,
with outflow gusts of 30-45 kt possible. Surface winds outside of
storms: NE-SE 5-15 kt, transitioning to NW this evening. Hot daytime
temperatures will increase density altitude today.

&&

.PREV DISCUSSION...
SHORT TERM...Today through Friday night...Mid and high level
moisture has come in from the south with radar showing rain
echoes in the southern Owyhee Mountains and along the NV/OR
border at 3 AM MDT. Lightning has been detected near Denio/NV
along the NV/OR border. Latest models develop a swath of
showers this morning from southern Harney County through
central Malheur County, into the Lower Treasure Valley, Upper
Weiser River Valley, and Boise Mountains, with scattered lighter
showers elsewhere in our CWA.  Instability for thunderstorms
is forecast to stay south of 44N this morning.However,
isolated to scattered strong thunderstorms will develop this
afternoon on the Idaho side as instability rapidly increases,
with gusts up to 50 mph along with small hail. Greatest
instability is forecast in the Upper Treasure Valley, Boise
Mountains, and throughout south-central Idaho. Meanwhile, the
air mass in Oregon will become become relatively stable this
afternoon, but southwest winds will increase to 20 to 30 mph
with gusts to 35 mph in Harney and Malheur Counties. These
winds will be ahead of a cold front that will move through
eastern Oregon this evening and western Idaho tonight. This
will lead to significant cooling Thursday through Friday as
the associated upper trough moves through. High temps in the
80s to mid 90s today will be replaced by upper 60s and 70s
Thursday, and 70s to lower 80s Friday, along with lighter
winds and mostly sunny skies. Low temps will also be noticeably
cooler Friday morning, 40s to lower 50s in the valleys and mid
30s to mid 40s in the mountains. A slight chance of showers
and afternoon thunderstorms will linger in the northern-most
mountains of our CWA as the upper trough passes by,

LONG TERM...Saturday through Wednesday...The upper level flow
will transition to southwesterly on Saturday ahead of the next
Pacific trough. This will promote hotter temperatures, reaching
roughly 10 degrees above normal. Clouds will increase throughout
the day as a cold front arrives late Saturday into Sunday. This
front will initiate breezy winds, cooler temperatures, and a
15-35% chance of showers and thunderstorms on Sunday. Daytime
instability for thunderstorm development will become greatest
over southwest/central Idaho, especially for the higher terrain.
Dry conditions with breezy winds are forecast for Monday, along
with temperatures reaching near to 5 degrees above normal
Monday through Wednesday.


&&

.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...KA
AVIATION.....SP
SHORT TERM...LC
LONG TERM....SH