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723
FXUS65 KTFX 182047
AFDTFX

Area Forecast Discussion
National Weather Service Great Falls MT
247 PM MDT Tue Jun 18 2024

.SYNOPSIS...

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Although the remainder of the week will largely be unsettled,
temperatures will be on the warming trend. Mostly dry and warm
conditions this weekend will trend cooler early next week as breezy
westerly winds develop.
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&&

.DISCUSSION...

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Through Friday... Strong upper level ridging across the eastern
CONUS will allow for upper level troughing to persist across the
western CONUS this week. Embedded waves within this troughing will
bring the best chances for mainly afternoon and evening showers and
thunderstorms this afternoon and Friday afternoon, but will be
around Wednesday and Thursday as well. Temperatures will be on a
warming trend this week, though overnight lows tonight will
largely be in the 30`s F, with elevated valleys dropping into the
20`s. Temperatures tonight will challenge record lows for the date
in many locations.

One thing to keep an eye on will be for an opportunity for more
organized thunderstorms Friday afternoon. If the present timing
holds, the combination of the passing shortwave, ample instability,
and sufficient shear will result in a respectable environment for
stronger storms.

Saturday into next week... Flow across the eastern CONUS finally
becomes more zonal, allowing systems to begin tracking eastward
again. As troughing from this work-week shifts eastward, another
will begin moving eastward across the northern Pacific, setting up
near the Canadian coastline by Friday night. This will result in a
brief period of upper level ridging across the northern Rockies. Dry
conditions are forecast Saturday through at least early Sunday, with
temperatures Sunday climbing to the warmest of the forecast period.

The next round of troughing will begin building in by Sunday
afternoon. There is a fair bit of uncertainty at this range with
respect to timing and depth/strength of this troughing, which leads
to decreased confidence on potential impacts. A more benign scenario
would result in just a period of breezy westerly winds in the
afternoon Sunday, primarily across the plains, while a more
impactful scenario would bring showers and perhaps a few
thunderstorms as well later in the day. As of now the more benign
scenario is favored, but trends will need to be monitored for
timing changes with this system.

Regardless, temperatures trend closer to normal for Monday, with
breezy winds looking to continue over the plains into early next
week. Small opportunities for showers and thunderstorms will be
around early next week, but specifics are murky at this point. -AM
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&&

.AVIATION...
18/18Z TAF Period

The primary concern this TAF period will be for lingering low
clouds, as well as numerous showers and scattered thunderstorms
developing this afternoon and early evening. Confidence in
timing/location of any thunderstorms was too low to warrant a
thunderstorm mention in TAFs at this time, but will be monitored
through the afternoon for amendments. The greatest uncertainty this
forecast period will be for fog development around daybreak
tomorrow. Clearing skies and recent precipitation will be favorable
for fog, but the length of clear skies prior to daybreak will
ultimately determine who does and who does not get fog. Mountains
are likely to be obscured through the evening. -AM

Refer to weather.gov/zlc for more detailed regional aviation
weather and hazard information.

&&

.PRELIMINARY POINT TEMPS/POPS...
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GTF  37  67  41  75 /  70  20   0  10
CTB  33  64  38  73 /  40  30   0  20
HLN  40  72  45  80 /  40  20   0  10
BZN  33  69  39  77 /  50   0   0  10
WYS  26  63  33  72 /  20   0   0  10
DLN  32  67  38  73 /  50   0   0   0
HVR  40  70  44  79 /  70  30  10  20
LWT  34  65  41  71 /  40  50   0  20
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&&

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

$$

http://www.weather.gov/greatfalls