Area Forecast Discussion Issued by NWS Boise, ID
000
FXUS65 KBOI 112044
AFDBOI
Area Forecast Discussion
National Weather Service Boise ID
244 PM MDT Thu Apr 11 2024
.SHORT TERM...Tonight through Saturday night...Upper low near
48/138W this afternoon is forecast to move SSE to 37/130W off
the California coast by Friday afternoon. Westerly flow aloft
will turn southwesterly and increasingly moist Friday.
Instability will increase in our CWA Friday afternoon with
steepening lapse rates, leading to numerous showers and
thunderstorms, strongest and most numerous (30 percent coverage)
Friday evening. SPC depicts a marginal risk of large hail and
strong outflow winds at that time. Upper flow will become
southerly Saturday and southeasterly Sunday when the low tracks
inland across the Great Basin. Warm again Saturday with more
showers (60 to 80 percent chance) and afternoon thunderstorms
(15 to 25 percent chance) Saturday afternoon in eastern Oregon,
while western Idaho is drier, then Saturday night again in
eastern Oregon and spreading into Owyhee County/ID.
High temperatures Friday and Saturday will be the warmest yet
this year with widespread 70s in the valleys and upper 50s and
60s in the mountains. Saturday looks like the warmer day by
about two degrees. Boise has about a 30 percent chance of
reaching 80F on Saturday.
.LONG TERM...Sunday through Thursday...A trough will move across
the NV on Sunday with a chance of showers and thunderstorms,
highest along the NV border. A trough digging south over British
Columbia will draw some of the moisture from the NV trough over
the area on Monday, keeping a threat of showers and thunderstorms.
As the cold front moves south into the Pacific NW, cooler air
will arrive from the north, with limited moisture. Temperatures
Tuesday and Wednesday lower to around 10-15 degrees below
normal. Showers will generally be focused over the higher
terrain during the afternoons as the trough remains overhead
through Wednesday. Forecast confidence is low beyond Wednesday.
&&
.AVIATION...VFR. Increasing clouds with isolated showers this
evening north of KBNO-KBOI. Surface winds: SW-SE 5-15kt. Winds
aloft at 10kft MSL: W-SW 15-25kt becoming 20-35kt by 09z/Fri.
KBOI...VFR. Isolated showers should stay north of terminal
tonight. Surface winds: SE 5-10kt.
Weekend Outlook...Generally VFR on Saturday, isolated
thunderstorms in central OR Saturday afternoon, surface winds
E-SE 10-20kt during afternoon. Areas of mountain obscuration
with MVFR to IFR in showers and thunderstorms on Sunday.
Variable surface winds 10-20kt Sunday.
&&
.HYDROLOGY...The Owyhee River below Owyhee Dam is expected to
remain above flood stage through Friday afternoon, then decrease
below flood stage late Friday evening.
&&
.BOI WATCHES/WARNINGS/ADVISORIES...
ID...None.
OR...None.
&&
$$
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SHORT TERM...LC
LONG TERM....KA
AVIATION.....KA
HYDROLOGY....LC