533
FXUS65 KBOI 061550
AFDBOI

Area Forecast Discussion
National Weather Service Boise ID
950 AM MDT Thu Jun 6 2024

.DISCUSSION...Showers got going earlier than expected, and one
thunderstorm was able to put down some lightning in Harney
county. Forecast was updated to boost precipitation chances in
SE Oregon and near the ID-OR border. Still on track for an
active afternoon/evening in far SW Idaho and the ID-NV Border as
the environment in that region has the most conducive
thunderstorm elements. Storms and showers will generally
disorganize as they traverse into the Snake Plain, but showers
may continue along outflow boundaries. Outflow winds this
evening could be up to 40-50 mph, with the greatest chance in
the Magic Valley and along the Nevada border. Friday and
Saturday continue to see convection along the ID-NV border, and
the whole region continues to be hot with temperatures roughly
15-20 degrees above normal. While Saturday will be the hottest
day, the most active day is looking to be Sunday. An upper
trough moves inland, and even though it loses energy quickly
after landfall, it will bring enough to our area to get showers
and thunderstorms going throughout the day.

&&

.AVIATION...VFR with high clouds. Isolated to scattered
showers/thunderstorms south of KBNO-KONO-KSNT line, mainly after
Thu/18Z. Stronger storms may be capable of erratic outflow wind
gusts of 35-45 kt. Surface winds: variable 10 kt or less, except
gusty near storm outflows. Winds aloft at 10kft MSL: W to SW
10-15 kt.

KBOI...VFR. Isolated showers and thunderstorms mostly south and
east of the terminal between 20Z and Fri/04Z, but there is a
10-15% chance of thunderstorms within 5 miles even this morning.
Erratic outflow wind gusts are also possible from nearby
storms, otherwise surface winds remaining less than 10 kt.

Weekend Outlook...VFR outside of thunderstorms/showers.
Afternoon showers and thunderstorms Saturday mostly across SE
Oregon and higher terrain south of the Snake Plain in Idaho.
Greater coverage shower/storm coverage, including lower valleys
on Sunday. Gusty outflow winds will be possible from showers and
storms. Otherwise surface winds generally 5-15 kt. Winds aloft
variable to 15 kt on Saturday becoming westerly 15-25 kt on
Sunday.

&&

.PREV DISCUSSION...
SHORT TERM...Today through Saturday night...Heat will build
through Saturday as an upper ridge amplifies over the interior
NW. Highs today are 5-10 degrees warmer than Wednesday with 3-8
degrees of further warming through Saturday. This will put lower
valleys between 95 and 100 degrees on Saturday while mtn
valleys push into the lower 80s. An increase in mid-level
moisture today will support a high-based showers and
thunderstorms this afternoon/evening. The deepest moisture and
best chance of development will be across southern Harney and
Malheur Counties in Oregon into southwest Idaho, generally south
of a line from Caldwell to Stanley. Southwest flow aloft will
direct showers/storms into the portions of Snake Plain, but
confidence in storms holding together as they cross the Snake
Plain is low (10-20%). Gusty outflow winds to 40 mph are
possible with isolated stronger storms capable of 50 mph gusts.
Friday and Saturday will see further rounds of afternoon
showers and thunderstorms carrying the same gusty outflow
threat. Focus of development both days be across higher terrain
of SE Oregon and SW Idaho south of the Snake Plain.

LONG TERM...Sunday through Thursday...The heat pulls back some
on Sunday as an upper trough pushes into the West injecting
clouds and increasing the chance for precipitation. Lower
elevations will see a 15-25% chance of showers and thunderstorms
while mtns hold a slightly higher chance (25-40%) through
Sunday evening. Lower elevations will see dew points push above
50F and precipitable water values over an inch (95th-99th
percentile) making it feel humid and increasing the chance for
locally heavy rain from showers/storms. A drier westerly flow on
Monday will bring a few more degrees of cooling and limit any
lingering chance of showers to higher elevations of w-central
Idaho. There is good model agreement on a west- southeast flow
setting up Tuesday and remaining in place through the end of the
week. This will keep dry weather in place with temperatures
around 10 degrees above normal, or highs near 90 in the valleys.

&&

.BOI WATCHES/WARNINGS/ADVISORIES...
ID...None.
OR...None.

&&

$$

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DISCUSSION...JM
AVIATION.....JM
SHORT TERM...DG
LONG TERM....DG