404
FXUS65 KTFX 120350
AFDTFX

Area Forecast Discussion
National Weather Service Great Falls MT
950 PM MDT Sun Aug 11 2024

.UPDATE...


&&

.SYNOPSIS...

Near normal temperatures will be around through much of this
week. Opportunities for showers and thunderstorms will be around
most days this week, with Tuesday looking to be the best day for
stronger thunderstorms across northeastern portions of the plains.

&&

.UPDATE...

No significant updates needed this evening. The cluster of
thunderstorms that moved through the Cut Bank area earlier this
evening will continue to weaken as it moves northeast along the
Canadian border through midnight. Have kept a slight chance of
showers and thunderstorms along the Northern Rocky Mountain Front
through around midnight or so, as there are a few lingering storms
west of the Continental Divide that may move over the Divide. Also
added mention of overnight fog over the plains along the Canadian
border where the showers and storms moved through and are
currently moving over. -Coulston

&&

.AVIATION...
11/18Z TAF Period

The primary concern this TAF period will be for at least isolated
showers and thunderstorms, primarily across Central and North-
central Montana this afternoon and early evening. A few overnight
showers and thunderstorms will be possible, especially late
tonight along the Idaho border. Areas that see precipitation today
and then clear out tonight will have an opportunity for a brief
instance of fog early tomorrow morning. -AM

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

&&

.PREV DISCUSSION...
/ISSUED 127 PM MDT Sun Aug 11 2024/

Through Monday...A brief period of weak upper level ridging is
building in for the afternoon and early evening across the
Northern Rockies. Although this is the case, ample daytime
heating will combine with lingering moisture to result in at
least isolated showers and thunderstorms through the evening
across Central and North-central Montana. Flow through the column
will largely be unidirectional, with limited speed shear. Hence,
showers and thunderstorms that do form today do not look to
become organized in nature. A brief gusty wind threat appears to
be the biggest concern this afternoon and evening with
thunderstorms. Slightly warmer temperatures aloft will inhibit
most, if not all chances for a shower or thunderstorm across
Southwest Montana this afternoon and evening.

As quickly as the upper level ridging builds in, southwesterly
flow aloft builds in tonight ahead of an approaching Pacific
Northwest trough. An embedded wave within this southwesterly flow
will pass across the region late tonight, providing enough
support for nocturnal showers and perhaps a thunderstorm or two,
primarily across Southwest Montana near the Idaho border.

Looking toward Monday, southwesterly flow persists, which will
help raise temperatures to near average across the region.
Additional showers and thunderstorms will be around Monday,
initially across Southwest Montana and along the Rocky Mountain
Front, shifting northeastward with time. Mixing looks to be a bit
deeper Monday, which will give a slightly higher risk of gusty
outflow winds from the stronger thunderstorms that do form.

A bit of a more robust shortwave will approach the region late
Monday night, yielding another opportunity for nocturnal showers
and thunderstorms, mostly near the Idaho border.

Tuesday... The aforementioned embedded wave within the persistent
southwesterly flow aloft will bring an increased opportunity for
showers and thunderstorms across the region Tuesday. The parameter
space from a shear perspective looks favorable for stronger
thunderstorms Tuesday, though uncertainty with respect to ongoing
showers and thunderstorms early Tuesday leaves a question as to
the thermodynamic favorability across the region. At this point,
areas with the best chances for stronger thunderstorms are across
eastern areas, where SPC has introduced a marginal risk for severe
thunderstorms.

Wednesday through the weekend... A bit of uncertainty begins to
sneak in later in the week timing additional systems tracking
eastward across the Northern Rockies. The takeaway at this point
is for temperatures near normal through the late week into the
weekend, with more or less daily low-end opportunities for showers
and thunderstorms, though some of these chances may come
overnight instead of the more typical afternoon and evening
variety of showers and thunderstorms. -AM

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  56  86  55  83 /   0  10  20  50
CTB  52  82  51  81 /  20  20  20  20
HLN  55  88  57  84 /   0  20  20  60
BZN  49  87  51  81 /   0  20  20  60
WYS  41  77  43  71 /  10  40  30  80
DLN  49  82  50  76 /  20  20  10  60
HVR  57  88  57  89 /  10  10  30  30
LWT  50  83  53  81 /   0  10  20  50

&&

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

$$

http://www.weather.gov/greatfalls