408
FXUS65 KBOI 080240
AFDBOI

Area Forecast Discussion
National Weather Service Boise ID
840 PM MDT Fri Jun 7 2024

.DISCUSSION...At 8 PM MDT thunderstorms were decreasing in
southeastern Owyhee County but a new cluster was moving across
southern Malheur County into western Owyhee County. Hi-res
models were not tracking the new storms well but the eastward
movement should keep them well south of the Snake Basin if
they hold together. Otherwise, current forecast is in good
shape with Saturday 1-3 degrees hotter than today, then 3-8
degrees cooler Sunday as a north Pacific trough comes inland,
with the greater cooling in Oregon. A 10-15 percent chance of
thunderstorms is indicated again along the ID/NV border late
Saturday,  but also in western Harney County. The trough will
increase the chance of afternoon/evening showers and
thunderstorms Sunday to 20-40 percent area-wide. Yesterday we
noted that models were forecasting a drastic cooldown next
weekend. Today`s models have backed away. Latest ECMWF still
has a cooling trough from the Gulf of Alaska but not as deep or
as far south as yesterday. The GFS has backed way off, now
leaving the upper low out in the Pacific near 140W whereas
yesterday it put the trough inland over our area. So it does
look cooler late next week, but not nearly as cool as models
showed yesterday.

&&

.AVIATION...Isolated showers and thunderstorms in southeast
Oregon near KBNO/KREO will end by Sat/06Z. Isolated to
scattered showers and thunderstorms will develop Saturday
afternoon and night across southeast Oregon and near the
Idaho/Nevada border. Gusty and erratic outflow winds to 40 kt
possible from storms as well as IFR/MVFR conditions due to heavy
rain. VFR conditions outside of thunderstorms. Surface winds:
variable 5-15 kt, except gusty near storms. Winds at 10k ft MSL:
W-SW 10-20 kt.

KBOI...VFR. Surface winds variable 6 kt or less overnight,
becoming NW 6-12 kt Saturday afternoon.

Sunday Outlook...Isolated to scattered showers and thunderstorms,
with the most coverage across the higher terrain. Stronger
showers and thunderstorms will produce brief IFR/MVFR conditions
with heavy rain and gusty winds. Outside of thunderstorms, VFR
conditions expected. Surface winds generally W-NW 5-15 kt.

&&

.PREV DISCUSSION...
SHORT TERM...Tonight through Sunday night...A weak wave in
Nevada will bring unsettled conditions to far SE Oregon and the
ID-NV border. Thunderstorms will develop around noon today and
last until around sunset. Storms may produce heavy rain and
gusty outflow winds, with the highest confidence for outflow
winds along the ID-NV border and southern Twin Falls county.
Outflow gusts will generally range from 40-50 mph, but there is
a 5% chance for a gust up to 60 mph. After sunset, isolated
showers will continue to impact SE Oregon, especially Harney
county. High temps today of 10 degrees above normal warm to 15
degrees above normal on Saturday. Saturday night through Sunday
night will be the most active precipitation day coming up as an
upper trough moves through. Precipitation chances throughout
the day range from 15-35%, with pockets of 40-50% chances in
the Boise Mtns, West Central Mtns, and southern Twin falls.
Thunderstorms will be possible throughout the area Sunday
afternoon/evening. The strongest storms are expected south of
Twin Falls, where the SPC has a Marginal Risk for severe
weather. Temps will drop with the upper low on Sunday back to
10 degrees above normal and hold steady there for the long
term.

LONG TERM...Monday through Friday...The long term is mostly
warm and dry as a low amplitude ridge develops. The flow is
mostly westerly, with brief periods of west-southwesterly flow.
This will keep temps around 10 degrees above normal each day.
A southwesterly flow dominates Thursday through Friday as a
deep upper low moves down from the Gulf of Alaska. As it moves
into the area, a closed low south of California may interact
with the Alaskan low to bring some moisture and favorable
dynamics. However, the current forecast shows a much drier
interaction, with chances of precip below 10%.

&&

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

&&

$$

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DISCUSSION...LC
AVIATION.....ST
SHORT TERM...JM
LONG TERM....JM