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Area forecast discussion
National Weather Service Great Falls Montana
244 PM MDT Tue Mar 28 2017

Discussion...

Rest of today through Thursday night...the main focus during this
period is the storm system that will impact The Rockies/northern
High Plains Wednesday night through Thursday night. Prior to then,
an upper level ridge combined with high pressure at the surface
should keep most of the area dry. Windy conditions will be found
along the rocky mtn front through tonight and possibly again
Wednesday evening for a short time. Wind gusts of 40-55 mph are
likely there. Below are some main takeaways regarding the incoming
system that will drop southeast through the pac northwest and close off/deepen
over The Four Corners region.

* Rainfall: the setup with this system favors some decent liquid
precip amounts, potentially on the order of 0.15-0.30", especially
along/south of a Great Falls to Lewistown line. However, with this
system, there will likely be one or more bands of heavier precip
and it is simply too early to know where those bands will be. It
must be stressed here that confidence in precip amounts is
moderate at best. The heavier bands of precip could put down a
half inch, liquid, or more, while areas outside of the bands may
see much lower amounts.

* Snowfall: for most of the event, snow levels will likely hover
around 6000-7000 feet. However, any area that sees heavier precip
rates, especially by Thursday night, could see snow levels drop
all the way down to the valleys/plains for a time. Light to
moderate snowfall accumulations look likely above 6000 ft. Below
this level, snowfall accumulations will be highly dependent on
snowfall rates/temperatures and confidence in accumulating snow is
much lower there.

* Impacts: at this time, significant impacts from rain and/or snow
are not anticipated. However, there could be some travel impacts
over mtn passes, especially SW Montana passes. The impacts might be the
greatest Thursday night as temps fall and Road surfaces cool.
Regarding rainfall amounts, we are not expecting widespread
flooding concerns, but will monitor this closely during the event.

* Confidence: overall confidence in the event is moderate. And,
again, it must be stressed that quantitative precipitation forecast/snowfall amounts are very much
subject to change as details become clearer over the next couple
of days, and some details may not be ironed out until closer to
the event, itself.

Martin

Friday through Tuesday...fairly quiet weather will reside over the
region to begin the weekend. Showers will generally be ending on
Friday morning as the main storm system from the middle portion of
the week exits the region. By late in the weekend and into Monday,
significant difference develop between the ec and GFS. The National
blend is significantly higher for pops for this period with the main
area of low pressure developing over far southeast Montana. The ec has
very little precipitation as the main storm system develops over the
Central Plains. Thus blended the pops for now. Additionally,
temperatures look to be cooler during this period, with the GFS much
cooler. If the GFS does pan out, the airmass will be cold enough for
mostly snow, and a significant snow event would occur over the
region. Otherwise, seasonable temperatures are currently forecasted
through the period until some trend for early next week can be
determined from the models. Brusda

&&

Aviation...
updated 1750z.
VFR conditions will prevail over the region through the period.
Expect some passing mid/high level clouds through 18z Wed along with
breezy west winds at times. Some mountains could become obscured
after 12z Wed with a few showers developing over the western
rockies. Brusda

&&

Preliminary point temps/pops...
gtf 38 61 43 52 / 10 20 20 60
ctb 34 54 37 50 / 10 20 10 30
hln 35 61 41 46 / 10 20 40 70
bzn 29 58 39 48 / 10 20 40 70
wey 16 41 30 38 / 10 10 70 80
dln 27 56 37 45 / 10 10 50 80
hvr 33 62 39 56 / 10 10 10 30
lwt 33 59 40 50 / 10 10 20 70

&&

Tfx watches/warnings/advisories...
none.
&&

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