954
FXUS65 KTFX 011740
AFDTFX

Area Forecast Discussion
National Weather Service Great Falls MT
1140 AM MDT Tue Oct 1 2024

...Aviation Section Updated...

.SYNOPSIS...

Breezy winds will be around today in most areas as temperatures
climb back above average. Temperatures cool slightly each day
Wednesday and Thursday before climbing well above average for
Friday. Chances for another breezy to windy period are increasing
for the late Friday through Saturday timeframe.

&&

.DISCUSSION...

Through tomorrow... A weakly anti-cyclonic northwesterly flow
aloft will become increasingly zonal through the day today. At the
surface, a pressure gradient is already developing this morning,
with relatively high pressure west of the Continental Divide
allowing areas in lee of terrain to develop a light downslope
wind. This has resulted in these areas seeing their overnight lows
just after sunset yesterday evening, with temperatures slowly
climbing through the overnight hours. The increasingly zonal flow
aloft will allow the gradient to increase further through the
morning and early afternoon, which will result in increasing south
to west winds across most of the region today. The strongest
winds aloft hold off until around or just after sunset and are
largely confined to the Northern Rocky Mountain Front and adjacent
plains. Forecast soundings show winds in excess of 50kts getting
within a few thousand feet of the surface around Cut Bank this
evening, but with a lack of daytime mixing to help, confidence is
not high that these stronger gusts will be observed at the
surface. The chance for a gust of 55 mph at Cut Bank late today
into the evening is 50%. Given the lack of strong confidence that
strong wind gusts will be realized at the surface on the plains
adjacent to the Rocky Mountain Front, no High Wind Warnings have
been issued at this time. Trends will need to be monitored in this
area today.

Zonal flow aloft trends back toward northwesterly for tomorrow
and becomes ever so slightly cyclonic in nature as a weak
disturbance ripples through the flow. The result will be for
temperatures taking a step back closer to normal, with a slight
chance for rain near the Canadian border through the day and
evening. Winds decrease compare to today, but will still be a bit
breezy at times over the western plains.


Thursday through Saturday... Upper level ridging builds in Thursday
into Friday morning, allowing benign conditions to settle in.
Temperatures trend a touch cooler for Thursday before the full
effects of the ridging are felt Friday, when temperatures will rise
much above average again. This period of nice weather will quickly
come to an end however as a quick moving upper level trough and
attendant cold front breaks down the ridging Friday afternoon into
Saturday. Forecast soundings show impressive winds aloft with this
system, easily in excess of 50 kts at 700 mb. The Friday evening
into Saturday timeframe will need to be monitored for strong winds
and gusts. At this time, the chance for a 55 mph gust is roughly 50%
at Cut Bank over this timeframe, with the chance for a 65 mph gust
around 35%.

Sunday into the middle of next week... Model ensembles are nearly
unanimous that an upper level ridge will build in Sunday into the
early portions of next week. Deterministic guidance does feature a
weak embedded wave passing through Sunday night. Hence, above
average and dry conditions are strongly favored, with a breezy
period not out of the question Sunday into Monday. -AM

&&

.AVIATION...
01/18Z TAF Period

VFR conditions prevail through the TAF period, with some mid to
level high level clouds through the period. Breezy southwest to west
surface winds pick up this afternoon and continue into early
Wednesday morning, especially over terminals along the North-Central
MT plains (KCTB, KHVR, KGTF, KLWT). Wind gusts of 30-40kts will be
possible during this time frame for those terminals. Additionally,
periods of mountain wave turbulence and low level wind shear (mostly
during the night past 02/06z) will be a concern due to stronger mid-
level winds aloft. -Wilson

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

&&

.FIRE WEATHER...

Elevated fire weather concerns will be in place today across the
plains as breezy winds overlap with relative humidity dropping into
the teens. While meteorological variables support a stronger fire
weather threat over grasslands, recent precipitation will put a
tamper on just how anomalous the threat will be. That said, be weary
of any activities that may be able to produce a fire start, as a
start may be difficult to contain in locally drier areas. -AM

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  74  52  65  34 /   0   0   0   0
CTB  69  38  59  31 /   0  10  20  10
HLN  78  50  71  36 /   0   0   0   0
BZN  77  42  74  31 /   0   0   0   0
WYS  64  28  67  24 /   0   0   0   0
DLN  76  42  71  30 /   0   0   0   0
HVR  77  44  62  35 /   0  10  10  20
LWT  75  50  63  32 /   0   0   0   0

&&

.TFX WATCHES/WARNINGS/ADVISORIES...
&&

$$

http://www.weather.gov/greatfalls