Scientific Forecaster Discussion
fxus65 kpih 072107
Area forecast discussion
National Weather Service Pocatello Idaho
207 PM MST Sat Dec 7 2019
no major changes to the forecast with the system moving through
the region. Snow began falling earlier this morning across the
central mountains and this will continue through the day and into
the first half of Sunday. Still expecting 4-10 inches of snow
across the central mntns west of Challis and MacKay (including The
Wood River Valley due to upslope enhancement), and similar values
across the upper snake Highlands, Teton valley, Caribou
Highlands, and Bear River Range.
Across the lower snake plain, as expected, seeing evidence of some
downsloping with temperatures pushing 50 degrees at pih and byi
while Ida remains in the upper 30s. Hi-res models continue to show
much of the snake plain dry for much of the afternoon and into the
evening hours. As far as precip type across the plain, models are a
touch warmer aloft compared to 24 hours ago so it appears that much
of the precip will be rain across the eastern Magic Valley over
towards Pocatello and Blackfoot. Across the Idaho Falls area perhaps
more of a rain/snow mix with snow the dominant precip type as you
head towards DuBois and Island Park and The Divide. This thinking
is supported by both global and hi-res model soundings. Towards
daybreak, it's not out of the question that some snowflakes may be
falling towards Pocatello but ground temps should be above
freezing limiting any significant impacts. Because of this
however, made sure to at least include mention of snow in the
forecast even though rain will be the more likely precip type.
Across the mountains no major changes to the ongoing forecast as we
still expect 4-10 inches of snow across the central mntns west of
Challis and MacKay (including The Wood River Valley due to upslope
enhancement), and similar values across the upper snake Highlands,
Teton valley, Caribou Highlands, and Bear River Range.
On Sunday, temps will warm into the upper 30s and lower 40s in the
valleys so will likely see continued rain or rain/snow mix across
the lower elevations into the early afternoon. As northwest flow begins to
filter into the region later in the afternoon Sunday, we may see a
convergence band of precip develop and with temps and snow levels
beginning to drop we could have a bit more of a chance for some
snowfall across lower elevations, if this scenario pans out.
As we move into the start of the work week, the remnants of the
upper trough stick around Mon over higher elevations east of I-15.
Lingering cloud cover seems likely and with light winds and fresh
snowpack for many areas, a return to what we saw for much of this
week with stagnant mist, fog, and low clouds seems likely across the
plains/valleys outside the central mntns. As we move late into the
week, models continue to show the potential for another storm system
to impact the area. It's still early but this one may be just a tad
colder allowing for greater snow potential across the valleys but
there are some indications this could be another mixed precip event
as well so for now the best advice is to stay tuned! Mckaughan
rain and snow will continue to increase into tonight and Sunday
morning. The concern is that outside of sun and dij, will there be
long stretches of poor flying conditions. Right now, we indeed are
forecasting that...but confidence isn't high at the moment.
Precipitation may end up being more showery or at least lasting
shorter periods than current tafs. If and when we do see
precipitation, expect drops to IFR (maybe even lifr). We do
expect long stretches of IFR/LIFR weather and more likely all
snow. Once we get later into Sunday, look for vcsh at sun and byi.
Northwest flow upslope may keep vcsh or snow showers and low
stratus going for pih, Ida and dij. Keyes
Winter Weather Advisory from 6 PM this evening to 11 PM MST
Sunday for idz060-062>066.
Winter Weather Advisory until 2 PM MST Sunday for idz071>075.