FXUS65 KBOI 012042
AFDBOI

Area Forecast Discussion
National Weather Service Boise ID
242 PM MDT Sat Jun 1 2024

.SHORT TERM...Tonight through Monday night...A weak trough is
approaching today, bringing some mild unsettled conditions.
Upper level clouds today are limiting shower development, but
isolated showers and scattered virga is evident over the higher
terrain this afternoon. There is still a 10-20% chance of
thunder over the West Central Mountains this evening. The trough
brings a weak cold front though this evening that will cause
keep winds a little breezy overnight with gusts to 25 mph. The
front will also bring cooler/drier air for early Sunday.

An atmospheric river in the Pacific will transport up to 1" of
PWat Sunday evening through Monday night. The enhanced moisture
flow is supporting precipitation chances of 70-90% for most of
the area, with chances of 90-100% over mountains. Rainfall
totals in the West Central Mountains and Boise Mountains are
around 1" in Valleys to 2" on ridges, with a few summits
forecast to receive even more. The significant mountain rain,
lows on Monday morning above freezing, and lingering snowpack
are creating some concern for small stream flooding in the
mountains. There is also some convective potential Monday
afternoon that could see some terrain driven storms forming.
This raises concern for rapid onset flooding, but convective
potential may be limited in the cloud cover and steady rain.
Even a little concern for convection on saturated soil and
snowpack was enough to warrant an increase to slight risk in the
WPC ERO. Overall, confidence in flood potential is a little too
low for a Flood Watch at this time as river, but a Hydrologic
Outlook has been issued. Elsewhere this event still looks like a
soaker, with portions of eastern Oregon in a marginal risk for
excessive rain. Storm total QPFs in the Snake Plain range from
0.2" along the southwestern edges and 0.5" along the
northeastern edges and foothills. Winds will gust to 20-30 mph
Sunday afternoon/evening ahead of the moisture.

.LONG TERM...Tuesday through Saturday...Zonal flow is forecast over
the area Tuesday with dry conditions. Ensemble forecasts continue to
show a strong upper level ridge developing over the region the
second half of next week resulting in hot/mostly dry conditions.
Temperatures will warm from around normal on Tuesday to 15-20
degrees above normal Thursday through Saturday. Models are showing
increasing moisture in southerly flow aloft late next week resulting
in a slight chance of showers (generally less than 20 percent) near
the Nevada border Thursday afternoon. The chance of showers
increases to 15-30 percent Friday and Saturday generally across
the entire forecast area.

&&

.AVIATION...VFR with mid and high level clouds spreading across the
area late this afternoon and evening. A slight chance of showers
until about 02/06Z, but low confidence (less than 20 percent) in any
of the showers reaching terminals. Slight chance (less than 20
percent) of thunderstorms in the West Central Mountains (including
KMYL). Gusts up to 30 kt near showers and thunderstorms. Surface
winds: W-NW 5-15 kt. 10k ft MSL winds: W 10-20 kt.

KBOI...VFR. NW winds 10 kt or less. Low confidence (less than 20
percent) of a shower after 02/00Z.

Sunday Outlook...VFR through Sunday afternoon with showers
developing in KBKE area. High confidence of MVFR conditions
developing across the north (KBKE-KMYL) associated with widespread
rain Sunday night. SW-NW winds 5-15 kt with local gusts to 25
kt.

&&

.HYDROLOGY...We're watching the northern mountains as an atmospheric
river will bring widespread rain Sunday night and Monday. Widespread
rainfall totals of 1.00 to 1.50 inches with locally higher amounts
are expected in these areas. Rain combined with high elevation
snowmelt will result in rising water levels in rivers, creeks, and
streams. Mainstem rivers currently are not forecast to reach flood
stage but some smaller tributary creeks and streams could reach or
exceed bankfull resulting in minor flooding. Mud and rock slides
could be an issue in steep terrain as well. There is a Hydrologic
Outlook in effect providing details as well.

&&

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

&&

$$

www.weather.gov/Boise

Interact with us via social media:
www.facebook.com/NWSBoise
www.twitter.com/NWSBoise

SHORT TERM...JM
LONG TERM....TL
AVIATION.....TL
HYDROLOGY....TL