FXUS65 KBOI 080308
AFDBOI

Area Forecast Discussion
National Weather Service Boise ID
908 PM MDT Sat Sep 7 2024

.DISCUSSION...Interesting water vapor satellite imagery this
evening showing pair of mid-level lows over the Pac NW. The
closest to our area is centered over s-central Oregon and has
supported showers and an isolated thunderstorm across SE Oregon
and far SW Idaho this evening. This feature will lift northeast
overnight shifting the chance of showers from SE Oregon into SW
Idaho Sunday morning. While it's been unimpressive with
lightning activity this evening, there remains a low chance of
a thunderstorm overnight and into Sunday morning. The thickest
smoke remains across the central mtns of Idaho and southerly
flow aloft will transport it northward through Sunday though
will need to keep an eye on smoke from fires in Oregon. Current
forecast is on track for tonight.

&&

.AVIATION...Mostly VFR. Areas of low VFR to IFR as smoke reduces
visibility surface and aloft, mainly across the north. Mountain
obscuration in smoke. Isolated showers and thunderstorms across
SE Oregon overnight spreading into SW Idaho late tonight and
early Sunday morning. Showers and thunderstorms may produce
gusty erratic outflow winds. Surface winds variable 10 kts or
less becoming SE-SW 5-15kt by 18Z Sunday. Winds aloft at 10kft
MSL: S-SW 10-20kt.

KBOI...VFR-MVFR in smoke. Surface wind: E-SE 4-7kt. Low
probability (20%) of isolated showers and thunderstorms between
12z-18z Sunday.

&&

.PREV DISCUSSION...
SHORT TERM...Tonight through Monday night...A shortwave over
southwest Oregon and northern CA will slowly move inland
tonight, producing isolated thunderstorms in Harney and Malheur
Counties this evening. As the shortwave moves across eastern OR
early Sunday morning, it will produce scattered showers and
isolated thunderstorms as it tracks northeast into western MT.
As the system moves east, a dry slot will end the precipitation
threat for most of eastern OR and southwest Idaho Sunday
afternoon, with the exception of Baker County OR and the west
central ID mountains lasting into Sunday evening. Dry southwest
flow is expected on Monday, with temperatures remaining around
10 degrees above normal.

LONG TERM...Tuesday through Saturday...Southwest flow continues
into Wednesday as an upper level trough moves south along the
British Columbia coast. Then a major pattern change ensues as a
deep upper level trough moves over the area. As the trough
approaches and moves overhead, shower and thunderstorm chances
increase to 30-50 percent in the lower elevations below 5000
feet, and 60-80 percent in the central ID mountains on Thursday.
The highest peaks above 9000 feet will see light snow. There is
a 40-70 percent chance of exceeding 0.25 inch of precipitation
in the mountains, and a 20-40 percent chance of seeing greater
than 0.5 inch in the central ID mountains with this storm
system. Temperatures will be around 10 degrees above normal on
Tuesday, lowering around 10-15 degrees below normal as the
system moves overhead Thursday and Friday, before moderating on
Saturday.

&&

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

&&

$$

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DISCUSSION...DG
AVIATION.....TL
SHORT TERM...KA
LONG TERM....KA