Area Forecast Discussion
Issued by NWS Great Falls, MT

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FXUS65 KTFX 230411
AFDTFX

Area Forecast Discussion
National Weather Service Great Falls MT
1010 PM MDT Thu Jun 22 2017

...UPDATED AVIATION SECTION...

.UPDATE...

Evening update has been published. Short term models continue to
struggle with the current northwest flow regime over the region,
especially with regards to POPs and sky cover. Models have
generally been to moist throughout the day and evening in terms of
POPs and sky cover across North Central Montana and along the
Rocky Mountain Front. With this said, given the combination of
weak lift associated with an embedded shortwave diving southeast
and upslope northwest flow, inserted mention of sprinkles and
even flurries (for elevations above 5,000ft) across portions of
North Central Montana and along the Rocky Mountain Front for
tonight and early tomorrow morning. Some of the
sprinkles/flurries may materialize into a brief shower, however,
given the dry low/mid levels I only felt comfortable enough to go
with the previously mentioned pesky sprinkle/flurry. Otherwise,
clearing skies are expected across Southwestern Montana, where
overnight low temperatures may fall near or slightly below
freezing. Should freezing temperatures be realized over these
areas, delicate/sensitive vegetation would be at risk if not
covered or protected. - Moldan

&&

.SYNOPSIS...

A upper-level disturbance will lead to an increase in cloud cover
and spotty showers across northern and central Montana the rest of
this evening and into the day on Friday. However, clearing skies
over southwest Montana could cause temperatures to fall to near or
slightly below freezing tonight, so delicate plants there should be
covered or otherwise protected. There will then be a drying and
warming trend beginning this weekend and lasting through the early
part of next week. The next chance of showers and thunderstorms will
come with an approaching system from the west by late Monday and
into Tuesday.

&&

.AVIATION...
Updated 0410Z.

VFR conditions will continue at least through Friday evening. Clouds
and winds have decreased across the forecast area this evening with
the exit of a disturbance in the northwest flow. However, another
weak disturbance will move southeast through North Central and
Central Montana through 15Z, bringing widespread mid level
cloudiness with a chance for light showers. At this time, there only
some weak echoes on radars in southern Alberta, so am not expecting
showers to be significant enough to mention in the TAFs. There will
be brief clearing across this area again between 12Z and 18Z, but
scattered to broken cloudiness will redevelop after 18Z. Southwest
Montana will remain just partly cloudy through this period.
Coulston

&&

.PREV DISCUSSION...
/ISSUED 530 PM MDT Thu Jun 22 2017/
Tonight through Saturday...Cold front with light showers/sprinkles
continues to move southward through the region. With temperatures
falling into the 50s and a brisk north wind...it does fell
chilly. Overnight lows will fall into the 30s in Southwest
MT...thus sensitive plants might need to be covered. Any snow
should be confined to ridge tops...mainly above 8000 feet.
Otherwise...a few showers continue into Friday along with
comfortable temperatures. The northwesterly flow aloft continues
over the region on Saturday...resulting in a few isolated showers.
Afternoon temperatures will be a touch warmer than Friday. Brusda

Saturday through Wednesday...Area remains under a NW flow aloft
Saturday as the large scale upper level trough progresses east across
the N-central CONUS. Though models are pretty limited in terms of
precip/coverage on Saturday, opted for at least slight chance pops
Saturday as embedded shortwave and upper jet energy combined with
somewhat unstable and cyclonic NW flow aloft should support some
afternoon shower and isolated thunderstorm development. Heights rise
Sunday and Monday as an upper level ridge briefly amplifies and
shifts east across the Northern Rockies and MT ahead of the next
trough from the NE Pacific approaching the West Coast. Afternoon
temperatures still slightly below seasonal averages Saturday warm to
above average by Monday and Tuesday of next week. Still a fair
amount of variability among models with the progression of the
Pacific trough inland by the middle of next week. However in any
case the upper ridge looks to weaken or be replaced by a weak trough
with an influx at at least limited moisture and shortwave energy
from the west/southwest for an increase in cloud-cover and potential
for afternoon shower/thunderstorm development. Hoenisch

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  66  38  68  44 /  10  10  10  10
CTB  64  39  66  43 /  20  10  20  20
HLN  73  43  72  47 /   0  10   0   0
BZN  73  37  71  42 /   0   0   0   0
WEY  67  29  67  35 /   0   0   0   0
DLN  70  37  72  43 /   0   0   0   0
HVR  68  40  71  44 /  20  10  10  10
LWT  63  38  65  40 /  10  10  10  10

&&

.TFX WATCHES/WARNINGS/ADVISORIES...
None.
&&

$$

weather.gov/greatfalls



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