017
FXUS65 KBOI 080233
AFDBOI

Area Forecast Discussion
National Weather Service Boise ID
832 PM MDT Mon Jul 7 2025

.DISCUSSION...No changes to forecast.  Upper level high over
the swrn US will build northward through the eastern Great
Basin Tuesday as a Pacific upper low moves toward the California
coast. This setup will increase southerly flow aloft and bring
hot weather to our area Tuesday, supporting our Heat Advisory
issued earlier today. On Wednesday the off-California low will
come inland bringing slight cooling. A surface cold front will
bring further cooling Thursday along with breezy winds. The
upper low will also bring mid-level moisture and increased
instability due to greater cooling aloft, leading to isolated
thunderstorms in our northern and western zones Tuesday
afternoon/evening, and then in our central and southern zones
(except along the NV border) Wednesday afternoon/evening. A
Fire Weather Watch has been posted for lightning Wednesday
afternoon and evening in eastern Oregon.

&&

.AVIATION...VFR under mostly clear skies. Isolated showers and
thunderstorms developing Tuesday afternoon across SE Oregon and the
west-central Idaho mountains. Gusts up to 40 kt near thunderstorms.
High density altitude due to hot temperatures on Tuesday. Surface
winds: variable less than 10 kt, becoming SE-SW 5-15 kt Tuesday
afternoon. Winds aloft at 10kft MSL: W 5-15 kt, becoming SE-SW
after Tue/12Z.

KBOI...VFR. High density altitude due to hot temperatures on
Tuesday. Surface winds: SE 5-10 kt, becoming variable less than
10 kt Tuesday afternoon.

&&

.PREV DISCUSSION...
SHORT TERM...Tonight through Wednesday night...High pressure
will continue to build into the region today, bringing very hot
temperatures and dry conditions Tuesday. Tuesday`s highs at
102-103F in the Boise metro area will be near record for this
time of year (104F), with locations near Emmett, ID reaching
nearly 106F. Despite relatively good overnight cooling, have
opted to add a heat advisory for Tuesday afternoon and evening
for the Treasure Valley zones.

A weak shortwave trough stemming from a closed low moving into
California will bring sufficient instability (400-700 J/kg of
MUCAPE) to southeast Oregon tomorrow afternoon and evening.
There`s a small risk of showers and thunderstorms with this
trough passage Tuesday afternoon and again Wednesday evening.
A weaker cold frontal passage will occur on Wednesday evening,
so have opted to expand shower and thunderstorm chances across
the region, with most locations seeing a 15-25% chance of
thunderstorms. With both sets of showers and thunderstorms
these days, dry surface air will limit precipitation and create
optimal conditions for gusty and erratic outflow winds. Some
hi-res models are showing gusts up to 40-50 mph with stronger
showers. Because of the threat of lightning in drier
thunderstorms and the higher confidence in coverage on
Wednesday, we`ve added a fire weather watch over southeast
Oregon zones for Wednesday afternoon and evening. Winds will
continue to stay elevated on Wednesday evening, with slight
improvement in humidity and much cooler temperatures thanks
to the cold frontal passage.

LONG TERM...Thursday through Monday...An upper trough moving
through the northern Rockies will send a dry cold front across
SE Oregon and SW Idaho on Thursday. The post-frontal winds are
expected to be gusty in the afternoon, especially in s-central
Idaho with gusts to 35 mph. Cooler temperatures arrive with the
passage of the front with valley highs in the 80s, which is
around 5 degrees below normal. A dry northwest flow aloft
follows for the end of the week and into early next week.
Temperatures begin to climb back up to slightly above normal by
Saturday and remain at least a few degrees above normal through
Monday.

&&

.BOI WATCHES/WARNINGS/ADVISORIES...
ID...Heat Advisory from noon to 9 PM MDT Tuesday IDZ012-014.
OR...Heat Advisory from noon MDT /11 AM PDT/ to 9 PM MDT /8 PM PDT/
     Tuesday ORZ064.
     Fire Weather Watch from Wednesday afternoon through Wednesday
     evening ORZ670-672>674.

&&

$$

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DISCUSSION...LC
AVIATION.....ST
SHORT TERM...SA
LONG TERM....BW