Granite, Oregon Weather Forecast Discussion

293
FXUS65 KBOI 100904
AFDBOI
Area Forecast Discussion
National Weather Service Boise ID
304 AM MDT Wed Sep 10 2025
.SHORT TERM...Today through Friday night...A well-defined
closed low over northern California this morning will approach
the region today, bringing widespread showers and thunderstorms.
Conditions are favorable for heavy rainfall with stronger
embedded storms, especially across southeast Oregon, where flash
flooding and debris flows are possible on burn scars.
Satellite and radar show a large area of steady precipitation
over northwest Nevada early this morning ahead of the low
circulation. As the low shifts north-northeast, this area of
rain will move into Harney and Malheur Counties. Precipitable
water values of 0.75 to 0.85 inches will support locally heavy
rainfall, highlighted in WPCs Marginal Risk for Excessive
Rainfall. By afternoon, precipitation will lift north and west,
allowing for partial clearing and renewed thunderstorm
development aided by upper-level dynamics and modest surface
instability (CAPE 200 to 500 J/kg).
High-resolution guidance shows storms initiating along the
NevadaIdaho border around 2 PM MDT, then tracking north-
northwest through the Treasure Valley, western Magic Valley,
west-central Idaho mountains, and into Baker County, as well as
northern Malheur and Harney Counties. This second round of
precipitation could bring additional heavy rainfall to southeast
Oregon, further elevating the risk of flash flooding across
burn scars, especially the Durkee/Cow Valley and Falls scars. A
Flash Flood Watch is in effect for this area. Although locally
heavy rain is also possible across the west-central Idaho
mountains, conditions appear less favorable as the strongest
storms are more likely for southeast Oregon this evening. In
addition to heavy rain, small hail and outflow winds up to 50
mph are possible with bulk shear across the southern forecast
area approaching 50 kts.
The low center will drift across the region on Thursday,
maintaining showers and thunderstorms with the greatest focus
near the low center in southeast Oregon and over the mountains
of southwest Idaho. Precipitation chances will decrease Thursday
night with the loss of daytime heating. By Friday, scattered
showers will linger over higher terrain, mainly Baker County and
the west-central Idaho mountains, as the low exits the area.
Temperatures will be near normal today, with valley highs in the
low 80s, then cool to 5 to 10 degrees below normal Thursday and
Friday.
.LONG TERM...Saturday through Wednesday...An upper-level ridge
will briefly build over the area Saturday, bringing a break from
precipitation and allowing temperatures to rebound to near
normal by Sunday. Another upper-level low will move into the
Pacific Northwest late Sunday into Monday, resulting in a 30 to
50 percent chance of showers and a slight chance of
thunderstorms during that period. Precipitation chances will
decrease Tuesday as the low shifts east. Overall, this pattern
will keep temperatures near to slightly below normal through the
extended period.
&&
.AVIATION...VFR. Scattered showers and isolated thunderstorms
mainly focused in eastern Oregon this morning. Otherwise partly
cloudy. Showers and thunderstorms area-wide after 19Z
Wednesday. Some storms could contain wind gusts greater than 40
kt. SFC winds variable 5-15 kt. Winds aloft at 10kft MSL: SSW
5-15 kt.
KBOI...VFR. Partly Cloud this morning. Chance for showers and
thunderstorms between 23Z Wednesday and 06Z Thursday. Gusty
outflow winds (40% of 35 kts or greater), small hail and heavy
rain could bring brief MVFR conditions. Winds become SE less
than 10 kt, before turning to the northwest Wednesday afternoon.
&&
.BOI WATCHES/WARNINGS/ADVISORIES...
ID...None.
OR...Flash Flood Watch from noon MDT /11 AM PDT/ today through this
     evening ORZ061>064.
&&
$$
www.weather.gov/Boise
Interact with us via social media:
www.facebook.com/NWSBoise
www.x.com/NWSBoise
SHORT TERM...JDS
LONG TERM....JDS
AVIATION.....JDS

NWS BOI Office Area Forecast Discussion