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000
FXUS65 KTFX 290215
AFDTFX

Area Forecast Discussion
National Weather Service Great Falls MT
815 PM MDT Sun May 28 2023

.SYNOPSIS...
Scattered showers and isolated thunderstorms will continue
through the afternoon today. Expect a few additional showers and
thunderstorms on Memorial Day, but most of the area will remain
dry for the holiday.

&&

.UPDATE...
Updated forecast is out. The only change this evening was to
extend the chances of thunderstorms over Central / Southwest MT
until a few hours after Midnight. Thunderstorms continue to rotate
around the upper level low to our west. Otherwise, the rest of the
forecast is on track. Brusda

&&

.AVIATION...
800 PM MDT Sun May 28 2023 (29/00Z TAF Period)

Main concern is isolated thunderstorms this evening. Most storms
will diminish over Central/Southwest MT by 09z Mon. Expect storms
to redevelop over far southwest MT mostly after 17z on Mon. Other
than some sort MVFR conditions in/near storms, generally VFR
conditions will prevail through the period. Brusda

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

&&

.PREV DISCUSSION...
/ISSUED 159 PM MDT Sun May 28 2023/

The final piece of a broad upper level trough that has been stuck
over the NW CONUS for the last week or so will finally move
through the area over the next two days. This is resulting in
widely scattered showers and thunderstorms across the area,
particularly south of a line from Great Falls to Lewistown. These
showers and storms will continue to slowly push eastward through
the day, and could bring up to a quarter inch or so of additional
rainfall through around 7 this evening, with showers and storms
dying out shortly thereafter.

As the base of the upper level trough pushes to our east on
Tuesday, our upper level flow will turn more westerly, allowing
for a bit of a reprieve, save for a few isolated showers that are
able to pop up during the afternoon heating. Wednesday will be
similar as westerly flow aloft continues, with isolated to
scattered showers and thunderstorms across the Southwestern
Mountains. -Ludwig

Thursday into the weekend... Ensemble and cluster guidance are in
pretty good agreement through the work week, with a ridge of high
pressure developing across the midsection of CONUS/Canada with a
trough developing across the western CONUS. Resulting flow aloft
in this pattern is south to southwesterly, which points towards
more rounds of showers and thunderstorms each afternoon and
evening through Friday. Deterministic guidance suggests better
moisture will sneak into the region Thursday into Friday from the
east. 48-hour probabilities for 1 inch of rain from Thursday
morning through Saturday morning are generally in the 20-40% range
for North-central Montana, and 10% or less across Southwest
Montana.

Uncertainty develops in the pattern heading into next weekend, but
most solutions favor some component of southerly flow aloft, which
would continue chances for showers and thunderstorms. -AM

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  50  75  49  78 /  20  20  10  10
CTB  50  76  47  79 /  20  20   0   0
HLN  51  78  52  81 /  20  30  10  20
BZN  44  74  46  77 /  50  30  20  50
WYS  36  64  34  68 /  50  60  40  70
DLN  43  72  45  74 /  40  20  20  50
HVR  52  80  52  81 /  10  20  10   0
LWT  47  72  49  74 /  50  30  10  30

&&

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

&&

$$

http://www.weather.gov/greatfalls