Area Forecast Discussion
Issued by NWS Great Falls, MT

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FXUS65 KTFX 232335
AFDTFX

Area Forecast Discussion
National Weather Service Great Falls MT
535 PM MDT Fri Jun 23 2017

...Aviation Section Updated...

.SYNOPSIS...

An upper level ridge of high pressure will gradually build over
the Northern Rockies over the weekend. As a result, expect a few
isolated showers over the region early this evening and again on
Saturday, while it will be mostly dry on Sunday. Afternoon
temperatures will gradually warm over the next several days, from
the mid 70s on Saturday to around 90 degrees by Monday.

&&

.DISCUSSION...

Tonight through Sunday...A northwesterly flow aloft continues to
reside over the region...resulting in a few light rain showers
along the divide. These showers will drift to the southeast this
evening...but should generally remain west of I-15. Otherwise
mostly clear skies will prevail...especially over Southwest MT.
Another cool/crisp night is expected, especially for the valleys
of the Southwest...thus some delicate/sensitive vegetation could
be at risk once again. On Saturday, the upper level ridge builds a
bit further north/east resulting in slightly warmer temperatures.
A few spotty light showers will once again be possible...mostly
over North Central MT. On Sunday, the upper level ridge continues
to drift further east, resulting in mostly dry and warm conditions
over the region. Brusda

Sunday Night through Thursday...The weekend warming trend peaks on
Monday as the upper level ridge axis passes over the region. Warm
temperatures Monday afternoon will produce adequate instability to
cause scattered afternoon and evening thunderstorms. Some of this
activity could persist late Monday evening, aided by a shortwave
trough approaching from the PacNW. A large scale trough
develops over western Canada on Tuesday, then drops into the high
plains through mid-week. Diverging model solutions provide little
useful guidance regarding the passage of shortwave features embedded
within the broadly NW flow aloft. Overall, temperatures trend cooler
Tuesday through Thursday, with slight chances for showers and
thunderstorms associated with the minor shortwave disturbances. PN

&&

.AVIATION...
Updated 2235Z.

Northwest flow aloft will remain in place over the Northern Rockies
and Northern High Plains through the 2400/2424 TAF period. VFR
conditions are expected through the entire TAF period, however,
lowering ceilings to around 5000ft AGL are possible at the KCTB,
KHVR, and KLWT terminals after 12z Saturday. Confidence in areal
coverage of these lower ceilings is low at this time, so only went
with prevailing SCT for these lowest ceilings over the
aforementioned terminals. - Moldan

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  44  72  47  81 /  10   0   0   0
CTB  42  71  45  80 /  10  10  10   0
HLN  47  76  50  84 /   0   0   0   0
BZN  42  74  44  82 /   0   0   0   0
WEY  35  70  36  77 /   0   0   0   0
DLN  43  74  45  81 /   0   0   0   0
HVR  45  74  47  82 /   0  10   0   0
LWT  41  68  43  77 /   0  10  10   0

&&

.TFX WATCHES/WARNINGS/ADVISORIES...

None.

&&

$$

weather.gov/greatfalls



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