High Wind Watch 1, NWS Boise, ID

Area Forecast Discussion
National Weather Service Boise ID
925 AM MDT Tue Mar 28 2017

.DISCUSSION...After dry wx today and tonight some of the new
12Z guidance shows rain beginning Wednesday earlier than our
current forecast, i.e.,  Wednesday afternoon vs Wednesday
evening.  No update at this time but faster timing may be
included in the afternoon package.  Otherwise, current forecast
is on track with mostly sunny wx today and increasing clouds
late tonight through Wednesday.  Warming trend as well through
Wednesday.

&&

.AVIATION...VFR. Increase in low-mid level cloud cover this
evening. Showers begin pushing into the northwest portions of the
CWA near KBNO, KBKE, and KMYL by early Wednesday morning and
afternoon. Surface winds, variable 10-20 kts. Winds aloft to 10k
feet MSL, northwest 10-15 kts becoming westerly 20-30 kts by
12z Wednesday.

&&

.PREV DISCUSSION...
SHORT TERM...Today through Wednesday...Dry and mild conditions
expected today as high pressure builds aloft. Areas of high
clouds will limit the development of fog before sunrise, but
may still see some development in the more sheltered mountain
valleys in Idaho.  Breezy conditions again today in areas of
southwest Idaho, south and east of Mountain Home; winds will
diminish after sunset.  Southwest flow aloft Wednesday as the
next Pacific system moves into the region. The cloud deck will
increase and light showers will develop from the northwest to
the southeast through the course of the day. Temperatures will
increase 3 to 8 degrees, from about normal today to above normal
Wednesday.

LONG TERM...Wednesday night through Monday...Warm and moist
southwesterly flow aloft is still on track to take aim on the
region Wednesday night through Thursday ahead of an approaching
trough out of the Gulf of Alaska. Snow levels during the period
of heaviest precipitation (Wednesday night through Thursday
morning) will average 8500 feet, thus snowfall will be limited
to the highest mountain peaks at first. Precipitation amounts
are impressive with this system, as the center of the upper
level trough passes by overhead, with the mountains easily
receiving 1.0 to 1.5 inches of liquid equivalent. This trough
will become a closed upper low in Nevada/Utah on Thursday, and
some valley locations could see upward of an inch of
precipitation. The exact track of the low will determine the
amount and extent of QPF. Snow levels fall to around 4000 feet
MSL Thursday night with accumulating snows likely at higher
elevations. A good chance that wrap-around moisture will
produce moderate snow accumulations along the NV/ID border
late Thursday night into Friday. Windy conditions will develop
Thursday afternoon which will persist into Friday as the upper
level low shifts toward the Four Corners region. An upper ridge
builds into the Pacific NW on Saturday for dry weather, mild
temperatures, and light winds. Next Pacific system brings a
chance of showers and cooler temperatures Sunday and Monday,
although forecast confidence is low on the timing and details
of these systems.

&&

.HYDROLOGY...Minor flooding still expected for the Boise River at
Glenwood for the next several days, with the flow remaining at
8100 cfs. Flood advisory continues for the near future in Camas
and northern Elmore Counties with flow still high on the Camas
Creek. Otherwise, rivers and streams are expected to remain below
flood stage, but will have to be monitored as the next system
moves in and new QPF and snowmelt increase flood potential once
more at the end of the week.

&&

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

&&

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DISCUSSION...LC
AVIATION.....JC
PREV SHORT TERM...AB
PREV LONG TERM....KA
HYDROLOGY....AB