202
FXUS65 KTFX 292359
AFDTFX

Area Forecast Discussion
National Weather Service Great Falls MT
600 PM MDT Wed May 29 2024

Aviation Section Updated

.SYNOPSIS...

After a few showers and thunderstorms across Southwestern Montana
this afternoon and evening, drier weather is expected to push into
North Central and Southwestern Montana for the rest of the week.
Expect highs to generally be seasonable across the area, with
most lower elevations seeing highs gradually warm from near 60 on
Thursday to the low to mid 70s for the weekend.

&&

.DISCUSSION...

Key Points:

-A few thunderstorms are expected across Southwestern Montana
this afternoon and early evening, some of which may bring gusty
winds and a heavy downpour

-Cooler and drier through the weekend

Short Term (through Thursday)... A cold front continues to push
through Southwestern Montana this afternoon, which has been the
focal point for showers and even a few strong thunderstorms this
afternoon that have brought some localized accumulating hail.
Further north across the Plains, cooler and drier air have
continued to work into the area, which has resulted in most areas
seeing highs some 15-20 degrees cooler than they were yesterday.
For the rest of the day today, expect showers and thunderstorms to
continue across Southwestern Montana as they gradually shift off
to the east, bringing briefly heavy rain, gusty winds, and small
hail as they move eastward, while the plains will see skies
gradually clear.

Thursday will be a fairly quiet weather day, with just a few rain
showers across the Hi Line along with some breezy winds as the
cool and dry air continues to push in from the north and west. We
will have to watch for some rises on streams and creeks across
Southwestern Montana as todays rainfall makes its way downstream,
but widespread flooding is not expected at this time. Ludwig

Friday through next Wednesday... A weak high pressure ridge is
forecast to move into the area on Friday, bringing at least one
day of drier conditions, lighter winds, and a return to near
normal temperatures. Model clusters indicate that a more
progressive westerly flow pattern will develop for the weekend
into the middle of next week, but there is some disagreement on
when the disturbances will move through the area. As a result, the
NBM keeps the area slightly warmer than normal with a chance for
showers and thunderstorms each day, especially over the mountain
areas of Central and Southwest Montana. -Coulston

&&

.AVIATION...

30/00Z TAF Period

Showers and thunderstorms will begin to wind down over the next few
hours across Central/Southwest MT. Satellite has been showing
occasional lightning strikes with showers, so I have kept the TEMPO
thunderstorm group for a few more hours. However, chances for
remaining thunderstorms remains low. As a result, there will be
lower VFR/MVFR conditions with precipitation. As showers move out of
the region, it will transition to VFR through the TAF period.
Beginning Thursday morning, KHVR will have low chances for some
isolated light showers passing through. Across Central MT and the
Rocky Mountain Front, breezy west winds persists overnight. One
thing to monitor is the potential for fog to develop in KWYS
Thursday morning due to low winds, clearer skies and if they receive
moisture from showers this evening. However, the probability was too
low to include in the TAFs. Mountain obscuration will persist
through the TAF period as well. -Wilson

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

&&

.HYDROLOGY...

A disturbance will move through the area through this evening,
with the focus for potentially heavy downpours from thunderstorms
being over the area along and east of a line from Dillon to White
Sulphur Springs to Lewistown. The main concern is that the rain
will fall on warm mountain snowpack, causing rapid runoff. Most
rivers should handle the extra water, as river levels are not
exceptionally high, but some creeks and streams will run high and
possibly out of their banks in some spots especially out of the
Madison, Gallatin, Little Belt, and Big and Little Snowy mountain
ranges. We are not anticipating widespread issues, but will
monitor the situation closely for possible localized flooding.
-Coulston

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  41  61  38  68 /  10  10   0   0
CTB  38  59  37  65 /  10  20   0   0
HLN  42  63  39  70 /  20  10   0   0
BZN  34  59  33  67 /  50  10   0   0
WYS  30  53  29  62 /  70  10   0   0
DLN  34  59  33  69 /  10   0   0   0
HVR  42  63  41  67 /  10  50  10  10
LWT  37  57  34  63 /  40  20   0   0

&&

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

$$

http://www.weather.gov/greatfalls