-- Discussion containing changed information from previous version are highlighted. --
876
FXUS65 KTFX 230525
AFDTFX

Area Forecast Discussion
National Weather Service Great Falls MT
1125 PM MDT Sat Jun 22 2024

UPDATED AVIATION SECTION

.SYNOPSIS...
Drier and warmer conditions will continue to move into the area
overnight tonight. On Sunday, temperatures will be hot over
portions of Central MT, with afternoon temperatures in the mid
90s. A few storms could develop on Sunday afternoon, mainly east
of a line from Havre to Lewistown. It will not be as hot for the
early part of the work week, with the chances for thunderstorms
increasing once again for Wednesday and Thursday.

&&

.UPDATE...

Given benign conditions forecast for the overnight into early
Sunday, no mentionable changes were needed this evening. -AM

&&

.AVIATION...
-- Changed Discussion --
23/06Z TAF Period

VFR conditions are generally forecast to continue through at least
24/06Z across North Central (KCTB, KHVR), Central (KLWT, KGTF,
KHLN), and Southwest (KBZN, KEKS, KWYS) Montana, unless otherwise
mentioned.

A shortwave low pressure trough will gradually move across the
Pacific Northwest through the period, causing the southwesterly flow
aloft to increase. The main concern for aviation from this will be
an increasing threat for mountain wave turbulence after 18Z,
especially over North Central and Central Montana, as well as an
increasing threat for low-level wind shear after 00Z on the Rocky
Mountain Front and across the Hi-Line as winds start to decouple.
Also, with temperatures warming into the mid 80s to lower 90s for
most lower elevations, density altitude issues are possible.

Otherwise, areas of high- and mid-level cloudiness will mainly pass
overhead. However, a few strong thunderstorms could develop between
20Z and 04Z east of a KGTF to KHVR line, including the KLWT area,
likely causing strong erratic wind gusts and possibly causing brief
heavy downpours and hail, which may cause brief periods of MVFR
conditions. -Coulston

Refer to weather.gov/zlc for more detailed regional aviation
weather and hazard information.
-- End Changed Discussion --

&&

.PREV DISCUSSION...
/ISSUED 500 PM MDT Sat Jun 22 2024/
Tonight through Sunday...The main concern for the rest of this
afternoon is the potential for an isolated thunderstorm on the
east side of the Bears Paw Mountains and then south of Grass
Range. If any storms develop in these areas, they should move off
into eastern/southeastern MT rather quickly by the evening hours.
Otherwise, just expect some passing clouds overnight. On Sunday,
hot temperatures will develop over Central/Southwest MT, with a
few locations near record high. Additionally, gusty west winds
will develop by Sunday afternoon along the Rocky Mountain Front
and in the Cut Bank area. There is only a 10 percent chance for
high winds over the Plains on Sunday afternoon, thus no high wind
statement will be issued at this time. With fuels starting to dry
out, there is some concern for potential fire statements, but
since about half the area is still fairly green, no fire
statements will be issued at this time either. By Sunday
afternoon, a weak upper level disturbance will once again move
through the eastern portions of Central MT. This could result in a
few strong storms, mainly east of a line from Havre to Stanford
during the afternoon and evening hours.

Monday through Tuesday...An upper level ridge will try to build
over MT during this period. This should result in mostly dry
conditions, along with slightly above normal temperatures.

Wednesday through Saturday...The upper level ridge will start to
break down on Wednesday, with a few storms developing by late in
the day over Central/North Central MT. On Thursday, there is the
potential for a more widespread thunderstorm activity, with the
potential for some storms to be on the strong side. The unsettled
weather conditions continue into Friday. It does start to turn
cooler by late in the week, with some locations over North Central
MT having afternoon temperatures close to 10 degrees below normal
on Thursday. The cooler temperatures and shower activity will be
short lived, as drier and warmer will start to move back into
Central MT on Saturday. Brusda

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  55  91  54  83 /   0   0   0   0
CTB  50  84  49  76 /   0   0   0   0
HLN  58  94  58  87 /   0  10   0   0
BZN  53  94  54  88 /   0  10   0  10
WYS  45  83  47  81 /   0   0   0  10
DLN  51  90  53  87 /   0   0   0   0
HVR  57  94  55  82 /   0  10   0   0
LWT  54  89  53  79 /   0  20  10   0

&&

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

$$

http://www.weather.gov/greatfalls