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afdtfx

Area forecast discussion
National Weather Service Great Falls Montana
500 PM MDT Thu Mar 23 2017

Updated aviation

Discussion...

Tonight through Saturday...large upper low continues to bring
widespread precip to our south and east...leaving US under mainly
dry ridging. Still can't rule out a few rain and mountain snow
showers across the west and south...with just some fair weather
cumulus clouds elsewhere. A weak wave does skirt the hi-line this
evening...perhaps producing a very isolated shower. Confidence was
not high enough to include this in the forecast. Overnight
tonight into Friday morning...the dry air in Idaho moves into our
region bringing mainly clear and dry conditions. Dry conditions
and breezy southerly winds are expected to be the story for
Friday. With relative humidity values expected to be in the 20s and wind gusts
generally 20 to 30+ miles per hour...those trying to get a start on Spring ag
burning should use caution or delay burning operations. Ridge
pushes out of the region Friday evening...bringing increasingly
moist SW flow. This combined with a weak cold front may produce a
few rain showers...with snow showers above 5000 feet Friday
evening through Friday night. Broadscale trough could then bring
chances for rain and snow showers across western...southern...and
some central portions of the County Warning Area. Snow levels could remain around
5000 to 6000 feet for Saturday...with little snow accumulations
expected. Winds may again be breezy on Saturday...mainly across
northern portions...which could once again elevate fire weather
concerns. Friday will see temps return into the 60s...with Friday
night's front bringing a slight cool down...but still above
average...temperatures on Saturday. Anglin

Saturday night through Thursday...remaining areas of rain or snow
clear to the east Saturday night with a departing upper level
trough. Ridging aloft will maintain fair weather Sunday and Sunday
night. The next Pacific system advances moisture up to the
Continental Divide by Monday afternoon. This longwave trough splits
while crossing the intermountain west, producing the highest chances
for precipitation Monday night across southwest Montana. Snow levels
remain uncertain, but currently suggest snow or mixed rain/snow
could occur overnight down into the southwest valleys Monday night.
Conditions improve later Tuesday through Thursday morning aside from
scattered, mainly mountain showers. Temperatures remain slightly
above average through the period. Pn

&&

Aviation...
updated 2300z.

VFR will prevail at all terminals through the taf period, while
westerly flow aloft backs to southwesterly after 12z/Fri due to an
approaching weather disturbance. After 18z/Fri, periods of mountain
obscuration due to cloud cover and snow showers are possible along
the Continental Divide.
Jaszka

&&

Hydrology...
300 PM update.

Water levels on the milk river and its tributaries in Blaine/Hill
counties remain elevated but are mostly below flood stage and
continuing to gradually decrease. Lodge creek near the Canadian
border remains near minor flood stage but is anticipated to decrease
further tonight with gauges upstream all showing decreasing water
levels. No flood warnings are currently in effect but we will
continue to closely monitor river conditions in these areas. Hoenisch

&&

Preliminary point temps/pops...
gtf 28 62 38 58 / 0 0 20 20
ctb 24 55 34 52 / 0 10 10 10
hln 30 61 37 55 / 0 10 30 20
bzn 24 56 36 52 / 0 0 30 30
wey 16 42 29 40 / 10 10 50 50
dln 27 54 33 51 / 0 10 30 20
hvr 27 62 37 59 / 10 0 20 0
lwt 27 58 36 53 / 0 0 10 20

&&

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

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