Area Forecast Discussion
Issued by NWS Great Falls, MT

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FXUS65 KTFX 242241
AFDTFX

Area Forecast Discussion
National Weather Service Great Falls MT
430 PM MDT Sat Jun 24 2017

.SYNOPSIS...

A northwesterly flow aloft will reside over the region
tonight...resulting in a few isolated light rain showers over North
Central MT this evening...while mostly clear skies prevail over
Southwest MT. On Sunday...an upper level ridge of high pressure will
build over the region...resulting in dry and warm conditions across
the region. It turns very warm on Monday...with afternoon highs
ranging from the upper 80s to mid 90s...with thunderstorms possible
Monday night.

&&

.DISCUSSION...

This evening through Monday night...Expect mostly dry isolated
showers over north-central Montana to diminish with the loss of
daytime heating and with the associated disturbances continuing to
move south and east away from the area. By late tonight the upper
ridge axis will begin to shift eastward bringing mostly clear
skies along with dry and warm conditions on Sunday. Temperatures
continue to increase on Monday as the thermal ridge shifts into
the state leading to hot conditions. However, as the ridge
continues to shift eastward, flow aloft over the state becomes
southwesterly late Monday with an increasing chance for showers
and thunderstorms as unstable air advects into the
region. A sharpening surface lee trough over our far eastern
plains counties will allow for gusty winds in the afternoon along
with dry conditions, allowing for an increased threat of critical
fire weather conditions. A cold front passes associated with a
surface low over central Alberta will combine with a mid-level
disturbance and allow for some showers and possibly thunderstorms
to develop Monday evening through early Tuesday. cc/mpj

Tuesday through Friday...A large and closed upper level low
develops over western Canada on Tuesday, then drops into the high
plains through the end of the week. This change to a generally
northwest flow aloft will maintain slightly cooler than average
temperatures, with periods of rain showers and afternoon
thunderstorms. PN

&&

.AVIATION...
Updated 1702z.

Northwest flow aloft will remain in place over the region today
through early Sunday morning. VFR conditions will prevail across the
forecast area but variable mid level clouds with a lone weak shower
or two will persist over north-central Montana. Some mountain
obscurations are possible along the Northern Rocky Mountain Front
but conditions should improve after 00Z Sunday. Winds will remain
generally light and variable. mpj/cc

&&

.FIRE WEATHER...

There is increasing concern for the potential of critical fire
weather conditions occurring Monday afternoon through early
evening ahead of a lee-side surface trough over Blaine and
possibly northeastern Fergus County. Gusty southeast winds are
expected ahead of this feature along with minimum afternoon
humidity levels dropping below 20 percent. With fuels rapidly
drying due to ongoing drought in these areas, we have opted to
issue a Fire Weather Watch for Blaine County in Fire Weather Zone
113 for Monday afternoon and early evening with this afternoon`s
forecast package. cc



&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  45  81  54  92 /  10   0   0  10
CTB  46  80  51  90 /  10   0   0  10
HLN  47  86  55  93 /   0   0   0  20
BZN  42  82  49  90 /   0   0   0  10
WEY  34  75  39  79 /   0   0   0   0
DLN  43  84  52  88 /   0   0   0  10
HVR  45  80  53  94 /  10   0   0   0
LWT  43  75  50  86 /  10   0   0   0

&&

.TFX WATCHES/WARNINGS/ADVISORIES...

Fire Weather Watch from Monday afternoon through Monday evening
for Blaine County.

&&

$$

weather.gov/greatfalls


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