Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Boise Idaho
233 PM MST Monday Feb 8 2016
Short term...tonight through Wednesday...
very quiet weather outside of the Snake River Valley through middle
week. Biggest problem is the extent of low clouds with patchy fog.
Think the airmass has finally started to prime itself with the
inverted conditions as easterly winds bring a cool moist flow down
the valley from eastern Idaho tonight through Wednesday. Last two
mornings the stratus pushes further west...by Tuesday morning it
should finally push into the lower Treasure valley. This should
bring an end to the above normal temperatures the valley has seen
last few days. Otherwise the upper ridge is expected to remain
stationary through Wednesday then weaken slightly. The inversion
will stregnthen as 700mb temperatures increase overnight. Outside
of the lower valleys...above normal temperatures will continue.
Long term...Wednesday night through Monday...valley inversions
will still be in place Wednesday night through Friday...but
thinking that valley fog and stratus may be limited due to an
increasing east to southeast flow over the region ahead of the
next weather system. Did not make any changes to the temperatures
as still some uncertainty as to when the inversion will break and
allow temperatures to warm. Models slowing down the timing of the
next weather system to move into the region so looks like dry
conditions will continue across the area Friday with precipitation
increasing at least over northern zones late Friday night and
Saturday. Models showing a ridge will rebuild over the area on
Sunday and remain over the region for Monday...but this ridge will
not be as strong as the current ridge and models also hinting that
flow aloft will be more zonal...therefore will keep a mention of
at least slight chance probability of precipitation over northern zones for Sunday and
Monday and dry everywhere else. Temperatures for Sunday and Monday
will be several degrees above normal.
Aviation...mainly VFR. Surface based temperature inversion will
persist for the next several days due to high pressure over the
region. Expect widespread IFR/LIFR fog and low stratus in the Snake
River Valley during the night and through early afternoon...with
patchy valley fog in the kbno...kbke and kmyl areas. Daytime heating
will provide enough mixing to dissipate some of the fog and stratus
late in the afternoon...but will redevelop again in the evening.
Surface winds variable 10 kts or less. Winds aloft northwest 10-20
knots up through 10k feet mean sea level.
warmer air is expected to push into the middle levels of the airmass
helping to stregnthen the inversion across the region. Low clouds
with patchy fog can be expected from the lower Treasure valley
through the Magic Valley...along with the Long Valley and Baker. Mixing
heights around 1000 feet are expected with transport winds from
the northeast through southeast around 10 to 15 miles per hour. Conditions
expected to persist through at least midweek.