380
FXUS65 KBOI 060224
AFDBOI

Area Forecast Discussion
National Weather Service Boise ID
824 PM MDT Fri Jul 5 2024

.DISCUSSION...Breezier conditions than forecasted are being
experienced this evening from Mountain Home through the Western
Magic Valley, with gusts up to 33 MPH reported so far. The winds
are expected to diminish by sunset. However, surface winds will
increase again on Saturday as a shortwave and jet max move
through the northwesterly flow, primarily affecting areas
northeast of the forecast region. This will bring wind gusts up
to 40 MPH across much of the area. Temperatures are anticipated
to reach the upper 90s, with some lower valleys potentially
hitting 100 degrees on Saturday.

A persistent upper-level trough over the northern plains looks
to keep the heat, with the upper-level ridge, primarily west of
the forecast area through at least Sunday. This will delay the
onset of the hottest temperatures until Tuesday across southeast
Oregon, expanding into southwest Idaho by Wednesday.
Nonetheless, temperatures across southeast Oregon and the lower
Treasure Valley are expected to be high enough to warrant heat
advisories through the weekend.

Overall, guidance has lowered temperature projections and 500 mb
heights significantly from previous runs. Maximum temperatures
are still expected to exceed 100 degrees in the lower valleys
from Monday through at least Thursday. However, ensemble
forecasts for max temperatures have dropped by 2-4 degrees for
Tuesday through Thursday, along with reduced probabilities of
exceeding 110 degrees. Wednesday now shows the highest
probability at around 20%, with the remaining days below 10% in
Boise. Monsoonal moisture from the southeast Wednesday through
Friday could further limit maximum temperatures. Despite this,
conditions are still favorable for a prolonged heat event, which
could be dangerous if not properly prepared for exposure to the
heat. An update on winds for tonight and Saturday will be
provided shortly.

&&

.AVIATION...VFR and clear. High density altitude due to hot daytime
temperatures will continue through next week. Surface winds:
variable less than 10 kt overnight, then W to NW 10-20 kt with 20-30
kt gusts Saturday afternoon. Winds aloft at 10kft MSL: NW 15-25 kt.

KBOI...VFR and clear. Surface winds: variable 3-6 kt overnight,
becoming NW 8-15 kt with gusts around 20-25 kt after Sat/18Z. High
density altitude due to hot daytime temperatures will through next
week.

Sunday Outlook...VFR and clear. High density altitude. Variable
winds 10 kt or less in the morning, then NW 5-15 kt with gusts of 15-
25 kt in the afternoon.

&&

.PREV DISCUSSION...
SHORT TERM...Tonight through Sunday night...A strong upper
level ridge will bring increasingly hot temperatures to the area
through the weekend as it drifts slowly east. Initially
off the coast, it will move inland by Sunday night. The
Excessive Heat Watch has been changed to a Heat Advisory for
Harney and Malheur counties, along with the lower Treasure
Valley of Oregon, for Saturday and Sunday. Temps will warm up
even more going into the long term, and the Watch continues for
most areas through next week.

Winds will increase tomorrow afternoon/evening, especially in
far SE Oregon and from near Mountain Home south and east, with
gusts 20-30 mph. Winds will be considerably weaker Sunday.

LONG TERM...Monday through Friday...I know it is starting to
sound like a broken record, but temps will continue to rise
going into next week. The upper level ridge will continue to
move slowly east, and will be centered over our area Tuesday
and Wednesday. An Excessive Heat Watch continues for most of the
area Monday through Friday, with Wed currently forecast to be
the hottest day. Numerous daily records will be set, and several
all-time-high records may be reached. It`s going to be a
dangerous time for those without air-conditioning, and for
those working outside. The watch will almost certainly be
upgraded to a warning as we get closer in time.

Multiple consecutive days of high heat take a cumulative toll
on the body that can seriously endanger life. This is
especially true for those with pre-existing health conditions,
BUT AFFECTS EVEN FOR THOSE IN PERFECT HEALTH, if reasonable
precautions are not taken.

&&

.BOI WATCHES/WARNINGS/ADVISORIES...
ID...Excessive Heat Watch from Tuesday afternoon through Friday
     evening IDZ011-013-028.
     Excessive Heat Watch from Monday afternoon through Friday
     evening IDZ012-014>016-029-030-033.
     Red Flag Warning from 3 PM to 9 PM MDT Saturday IDZ424-426.
OR...Excessive Heat Watch from Monday afternoon through Friday
     evening ORZ061>064.
     Red Flag Warning from 3 PM MDT /2 PM PDT/ to 9 PM MDT /8 PM
     PDT/ Saturday ORZ636-637.
     Heat Advisory from noon MDT /11 AM PDT/ Saturday to noon MDT
     /11 AM PDT/ Monday ORZ061-063-064.

&&

$$

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DISCUSSION...JDS
AVIATION.....SH
SHORT TERM...SP
LONG TERM....SP