FXUS65 KBOI 030208
AFDBOI

Area Forecast Discussion
National Weather Service Boise ID
808 PM MDT Wed Oct 2 2024

.DISCUSSION...Slightly cooler tonight and Thursday behind today's
dry cold front. The supporting flat upper trough will exit east
Thursday followed by a more amplified upper air pattern consisting
of a ridge in the Great Basin and a trough approaching from the
Gulf of Alaska. This pattern will bring warmer air Friday, with
increasing southwest wind in eastern Oregon and the southwest
Idaho highlands, before a north Pacific cold front comes rapidly
inland late Friday. Wind speeds will approach advisory criteria
in our southern and western zones and support a Fire Weather
Watch due to low humidity Friday afternoon and early evening.
The cold front late Friday will support a 30-50 percent chance
of rain showers in our northern zones, and also a 5-15 percent
chance of thunderstorms there. Current forecast has all this.
No updates.

&&

.AVIATION...VFR. Patchy smoke, mainly in central ID Mountain
valleys. Surface winds: NW 5-15 kt, becoming variable less than
10 kt by 03/06Z. Winds at 10kft MSL: NW 20-30 kt.

KBOI...VFR. NW winds around 5 kt becoming variable less than
5 kt by 03/06Z.

&&

.PREV DISCUSSION...
SHORT TERM...Tonight through Friday night...The weak cold
front passed through the region earlier today has moved east,
which will allow for cooler temperatures tomorrow. High
pressure off the coast of northern California will extend into
our area, allowing for mostly clear skies, warm temperatures,
and stable conditions around the region through Friday morning.

Forecast has changed slightly since the morning, with the NAM
and ECMWF backing off on precipitation extent into our region
on Friday afternoon. The cold front will still move through the
region later on Friday, with extensive warming early on Friday
afternoon. This will allow for instability to bring about a
5-15% chance of thunderstorms to the Central ID Mountains. Winds
will be high as well, especially in southeast Oregon near the
Nevada border and on ridgetops in the Central ID Mountains.
Sustained speeds will be around 20-30 mph with gusts anywhere
from 40-50 mph by the later afternoon. Precipitation chances
from showers will be limited across the region, with modeled
precipitable water values low, around the 30-40th percentile at
0.40"-0.50" anticipated on Friday evening. The best chance will
be in the Central ID Mountains with around a 30-40% chance of a
trace to 0.01" of rain on Friday evening-Saturday morning.

LONG TERM...Saturday through Wednesday...The ridge will begin
to build back in on Saturday morning, bringing a return to
warming and drying conditions, with near record daytime highs,
through Monday. Winds will be light and follow a diurnal trend
each day. Models are hinting at a very low chance of
precipitation from a weak trough passage to our south on Monday
evening into Tuesday morning. Confidence is low in accumulation
or location of precipitation. Better agreement exists by later
in the week amongst deterministic models on southwest flow ahead
of a deep upper level trough passage later in the work week.
This will likely only lead to increased cloud cover and cooler
temperatures by later in the week.

&&

.BOI WATCHES/WARNINGS/ADVISORIES...
ID...Fire Weather Watch from Friday afternoon through Friday
     evening IDZ421-423-426.
OR...Fire Weather Watch from Friday afternoon through Friday
     evening ORZ636-637.

&&

$$

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DISCUSSION...LC
AVIATION.....SP
SHORT TERM...SA
LONG TERM....SA