Area Forecast Discussion
Issued by NWS Boise, ID

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FXUS65 KBOI 250238
AFDBOI

Area Forecast Discussion
National Weather Service Boise ID
838 PM MDT Thu Sep 24 2020

.DISCUSSION...
Our CWA will stay dry through midday Friday.  A storm in the
Pacific near 45/135 is racing eastward under strong zonal flow
and will reach our CWA late Friday and especially Friday night.
This storm promises rain for most areas but especially in the
north where the Buck wildfire is. The fire and the rest of the
west-central Idaho mountains should receive about a half inch
of rain by early Saturday. After this storm exits late Saturday
the upper ridge will rebuild and last through the coming week
with another long period of warm, dry weather.  This is all
well-covered by the current forecast. The smoke has cleared but
the HRRR model brings a brief resurgence to southeast Oregon
Friday morning before the Pacific storm comes in. The storm
will then push all the smoke out at least through Sunday.

&&

.AVIATION...
Mainly VFR. Rain showers spreading into Baker County/Oregon and
the west central Idaho mountains Friday afternoon, then south
across southeast Oregon and the Snake River Valley Friday night.
Surface winds variable 10 kt or less, becoming west 10-20 kt
Friday afternoon and evening, with gusts to around 30 kt. Winds
aloft near 10k feet MSL 20-35 kt.

Weekend Outlook...Mainly VFR. Showers will continue on Saturday,
mainly in Baker County/Oregon and the west central Idaho mountains.
Snow levels 7k-8k feet MSL. Showers will end Saturday evening.
Expect breezy west to northwest winds through the Snake River
Valley Saturday afternoon and evening. Skies will be mostly clear
late Saturday night through Sunday.

&&

.PREV DISCUSSION...
SHORT TERM...Tonight through Saturday night...Clouds will remain
across the region tonight into Friday ahead of the next system for
Friday night/early Saturday. Breezy conditions this afternoon will
diminish after sunset. Next system will bring showers to our
northern zones Friday afternoon which will spread southward into
the Western Snake River Plain by early Saturday morning. The West
Central Mountains could see up to a half an inch of rain through
Saturday with the valleys seeing less than a tenth. Cold
northwesterly flow will keep temperatures below normal on
Saturday.

LONG TERM...Sunday through Thursday...Models have trended a
little farther west with the upper level pattern on Sunday, with
a strong upper ridge centered off the northern California coast
and an upper trough diving through the northern Rockies and into
the northern Plains. As a result, temperatures will remain about
5 degrees below normal on Sunday, but dry conditions are expected.
Models continue to show the upper ridge amplifying and shifting
over the West Coast early next week, pushing the jet stream north
into Alaska and northern Canada. Temperatures will climb back to
around 5-10 degrees above normal next week. Our location east of
the ridge axis as well as northwesterly flow aloft will help to
confine even warmer air associated with the ridge to our west.
Mostly clear skies will prevail with no chance of precipitation
through the week.

&&

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

&&

$$

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DISCUSSION...LC
AVIATION.....JT
PREV SHORT TERM...JDS
PREV LONG TERM....ST


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