Heavy Rain in Oregon, June 11 to 12, 2022

Area Forecast Discussion
National Weather Service Boise ID
900 AM MDT Sat Jun 11 2022

.DISCUSSION...Showers are moving through Baker County this
morning, and this activity is expected to increase in intensity
and area coverage as it continues there and moves/develops east
into the West Central Mountains this afternoon. Thunderstorms are
most likely today and tonight north of a line from Burns to Boise
to Atlanta. Heavy rain will be likely with the stronger storms,
and they will also be capable of small hail and gusty winds. The
chance for thunderstorms increases Sunday and spreads south to the
NV border. Heavy precipitation is even more likely tomorrow. A
flood watch will be in effect in the northern higher terrain from
noon to midnight, with mudslides, especially near burn scars, the
main threat. Severe storms (hail to 1 inch in diameter or larger,
wind gusts to 50 kts or stronger) are possible tomorrow, and SPC
has kept the area in a marginal risk for severe storms. All this
is handled well in the current forecast and no update is planned
for this morning.

&&

.AVIATION...Mainly VFR. Showers in Baker County Oregon and the west
central Idaho mountains this morning spreading south to KBNO, KEUL,
and KBOI this afternoon. Isolated to scattered thunderstorms with
gusty winds, small hail, and locally heavy rain this afternoon and
tonight. Surface winds: variable up to 10 kt, then 5-15 kt with
gusts 20-30 kt after 17z. Winds aloft at 10kft MSL: SW 20-35 kt.

Sunday Outlook...Widespread showers. Isolated thunderstorms in the
morning becoming more numerous in the afternoon, with gusty winds,
small hail, and locally heavy rain. MVFR to LIFR conditions in rain
and low clouds. Mountains obscured. Surface winds: variable to 10 kt
becoming SW-NW 10-20 kt in the afternoon with gusts over 40 kt near
thunderstorms.

&&

.PREV DISCUSSION...
SHORT TERM...Today through Monday night...A very moist Pacific
flow remains just to the north of our area early this morning. The
plume of moisture will shift southward today as showers will
develop by late morning across northern areas, mainly from Baker
County to the West Central Mountains. In addition to the showers,
instability parameters are supportive of thunderstorms this
afternoon. Some of the thunderstorms may be strong - accompanied
by gusty winds, small hail, and heavy rain. The convection will
continue through this evening. The strength and coverage will
decrease overnight, although scattered showers will continue along
with a slight chance of thunderstorms.

On Sunday, there are two concerns with the thunderstorms. The
first is a threat of excessive rainfall rates with some of the
stronger storms. The main threat areas are the higher elevations
of Baker County and central Idaho where heavy rain on steep
terrain may cause mud/rock slides and localized flooding in flood-
prone locations. The other concern is the marginal threat of
severe thunderstorms per latest outlook from the Storm Prediction
Center across all of southeast Oregon and southwest Idaho. The
presence of strong winds aloft combined with moderate instability
will support organized isolated thunderstorms capable of producing
large hail and damaging winds.

Showers will persist through Sunday night as an upper trough moves
through the region. A cold front will move through ahead of the
disturbance, accompanied by gusty winds. Snow levels will fall to
around 5000-6000 feet on Monday with light snow accumulations
possible in the northern mountains above 6000 feet. Showers will
linger across the north through Monday night as an upper trough
settles into the Pacific Northwest. Temperatures will trend much
cooler each day.

LONG TERM...Tuesday through Saturday...Fair skies, slightly
cooler with breezy West winds are the expected conditions across
most of the region on Tuesday with the exception the Boise and
West Central Mountains where showery conditions are anticipated.
Look for rain showers along the most lower elevations (of those
areas) with snow showers in the higher mountainous terrains until
later that evening. These showery conditions will diminish and
eventually dissipate as the dominating, well developed (defined)
low and its associated moisture are pushed eastward. Fair skies
and lighter winds will move in behind and spread across the entire
region lasting through Friday morning as drier ridging takes
over. This will allow for area high temperatures to increase from
the low to mid 60's up to the mid 70's on/by Wednesday and carry
on to peak out around the 80's and 90's starting Thursday.
Increasing clouds and chances for showers will start to invade the
western sections of the region starting late Friday as the
effects of another strong, North Pacific low pressure system
nears. Expect these chances for showers to spread across the
entire region by late Saturday. Winds speeds should also increase
to breezy levels.

&&

.BOI WATCHES/WARNINGS/ADVISORIES...
ID...Flood Watch from Sunday afternoon through Sunday evening
     IDZ011-013-028-033.
OR...Flood Watch from Sunday morning through Sunday evening ORZ062.

&&

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DISCUSSION...SP
AVIATION.....JT
PREV SHORT TERM...BW
PREV LONG TERM....WH