Red Flag Warning 15, NWS Boise, ID

098 
WWUS85 KBOI 081910
RFWBOI

URGENT - FIRE WEATHER MESSAGE
National Weather Service Boise ID
110 PM MDT Wed Sep 8 2021

IDZ402-403-090300-
/O.CON.KBOI.FW.W.0015.000000T0000Z-210909T0300Z/
Eastern Payette National Forest-Northern Boise National Forest-
110 PM MDT Wed Sep 8 2021

...RED FLAG WARNING REMAINS IN EFFECT UNTIL 9 PM MDT THIS EVENING
FOR GUSTY WINDS AND LOW RELATIVE HUMIDITIES FOR EASTERN PAYETTE
NATIONAL FOREST AND NORTHERN BOISE NATIONAL FOREST...WHICH ARE
FIRE WEATHER ZONES 402 AND 403...

* WINDS...Gusts up to 30 mph.

* RELATIVE HUMIDITY...8 to 15 percent.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A Red Flag Warning means that critical fire weather conditions
are either occurring now, or will occur shortly.

&&

$$


W

187 
WWUS85 KBOI 090247
RFWBOI

URGENT - FIRE WEATHER MESSAGE
National Weather Service Boise ID
847 PM MDT Wed Sep 8 2021

...RED FLAG WARNING WILL EXPIRE AT 9PM MDT...


IDZ402-403-090400-
/O.EXP.KBOI.FW.W.0015.000000T0000Z-210909T0300Z/
Eastern Payette National Forest-Northern Boise National Forest-
847 PM MDT Wed Sep 8 2021

...RED FLAG WARNING WILL EXPIRE AT 9 PM MDT THIS EVENING FOR
GUSTY WINDS AND LOW RELATIVE HUMIDITIES FOR EASTERN PAYETTE
NATIONAL FOREST AND NORTHERN BOISE NATIONAL FOREST...WHICH ARE
FIRE WEATHER ZONES 402 AND 403...

With sunset, relative humidity values are increasing and wind
speeds are decreasing. Therefore, the warning will be allowed to
expire on schedule at 9 pm MDT.

$$


W

Area Forecast Discussion
National Weather Service Boise ID
922 AM MDT Tue Sep 7 2021

.DISCUSSION...Smoke is especially prominent this morning and HRRR
continues it through at least Wednesday night. Upper ridge over
the Great Basin this morning is forecast to drift slowly to the
Four Corners area Thursday. Smoke should begin to decrease from
the west Thursday and even more Friday when a Pacific trough comes
inland with a chance of showers and afternoon thunderstorms. Fire
weather concerns will increase Wednesday afternoon when west/
northwest winds increase, with low humidity. No updates at this
time.

&&

.AVIATION...Mostly VFR. Widespread smoke layers with periods of
MVFR visibility and terrain obscuration. Surface winds: mostly
light and variable, but with southwest 10-15 kts mainly near KBKE
21Z to 03Z, and west to northwest 10-15 kts crossing west to east
across Harney County/Oregon and KBNO area by Wednesday morning.
Winds aloft at 10k ft MSL: northwest 10-20 kts becoming southwest
10-20 kts early Wednesday morning.

&&

.PREV DISCUSSION...
SHORT TERM...Today through Thursday night...An upper ridge will
amplify over the area today warming temperatures several degrees
from yesterday. Southwest flow aloft will increase on Wednesday
returning gusty winds to the higher elevations Wednesday
afternoon. By Thursday some mid-upper level moisture will make its
way into the region and could pair up with an approaching short
wave trough to introduce a slight chance of precipitation late
Thursday. However, confidence on timing of the trough remains
low. Smoke will continue to funnel into the region on the west-
southwest winds aloft. This will limit heating potential through
the period, though temperatures will still be well above normal.

LONG TERM...Friday through Tuesday...Ensemble models in fairly
good agreement that a shortwave passing through the westerly
flow to the north of the forecast area will be able to support
showers, thunderstorms, and breezy conditions across the area on
Friday, and drop temperatures about 10 degrees. Some showers may
linger in the mountains on Saturday, as the flow turns more
northwesterly, rather than southwesterly, and which should help
to push some of the smoke and haze out of the area, and allow
temperatures through the weekend to get down to near normal.
Beyond the weekend, the ensembles have quite a variation in
solutions, but appears to be a bit more support for weak
troughiness and cooler temperatures for early next week, rather
than a return to a strong ridge.

&&

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

&&

www.weather.gov/Boise
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www.twitter.com/NWSBoise

DISCUSSION...LC
AVIATION.....JDS
PREV SHORT TERM...DG
PREV LONG TERM....TB