128
FXUS65 KTFX 192326
AFDTFX

Area Forecast Discussion
National Weather Service Great Falls MT
525 PM MDT Wed Jun 19 2024

Aviation Section Updated

.SYNOPSIS...

This afternoon and evening and Thursday afternoon and
evening there will be isolated showers and thunderstorms primarily
across North-central and Central Montana. On Friday afternoon and
evening a strong shortwave trough will move through the area which
will bring strong to severe storms to North-central and Central
Montana. Saturday and Sunday it will warm up over the area. For
Monday through the middle of next week there is uncertainty in the
weather pattern at this time.

&&

.DISCUSSION...

This afternoon through Thursday... This afternoon there
will be isolated showers and thunderstorms across North-central and
Central Montana and the northern portion of Southwestern Montana due
to a shortwave that is moving through the zonal upper-level flow.
North-central and Central Montana have a 10 - 40% chance for a tenth
of an inch of rain or greater this afternoon and evening. Thursday
morning portions of North-central and Central Montana that receive
rain have a low chance for patchy fog. On Thursday an upper-level
ridge begins to move over North-central, Central, and Southwestern
Montana. This will bring warmer temperatures to the area on
Thursday. On Thursday an upper-level shortwave moves through the
upper-level ridge which will produce isolated showers and
thunderstorms over North-central and Central Montana. On Thursday
there is a 10 - 20% chance for 5 hundreths of an inch of rain or
greater across North-central and Central Montana.

Friday... On Friday the upper-level ridge remains over North-
central, Central, and Southwestern Montana. This will keep about
seasonal average temperatures across the area. During Friday
afternoon and evening a strong shortwave trough moves through the
area which will bring strong to severe storms to North-central and
Central Montana. There will be heavy rain with some of these storms
in addition to hail and strong wind gusts. On Friday in Hill,
Blaine, Eastern Choteau, and Fergus Counties there is a 20 - 50%
chance for half an inch of rain or greater. On Friday across the
rest of North-central and Central Montana there is a 20 - 50%
chance for a quarter inch of rain or greater. On Friday across
Southwestern Montana there is 10 - 20% chance for a tenth of an
inch of rain or greater. Continue to monitor the forecast for
details.

Saturday and Sunday... On Saturday an upper-level ridge begins to
move back over North-central, Central, and Southwestern Montana.
This will warm up temperatures and bring dry weather to the area. On
Sunday the upper-level ridge will remain over North-central,
central, and Southwestern Montana. This will continue to warm up
temperatures. On Sunday Central Montana and the lower-elevations
of Southwestern Montana have a 50 - 90% chance of temperatures of
90 or greater. On Sunday it will be dry across North-central,
Central, and Southwestern Montana.

Monday through next Wednesday... On Monday clusters indicate that an
upper-level ridge is over Eastern Montana with southwest flow
aloft over North-central, Central, and Southwestern Montana. The
strength and exact positioning of this ridge differ between
clusters. On Tuesday two of the clusters (44% of ensemble
members) have an upper-level ridge over North-central, Central,
and Southwestern Montana. The other two clusters (56% of ensemble
members) have an upper-level trough moving over the area. On next
Wednesday the clusters are very similar to Tuesday over North-
central, Central, and Southwestern Montana. This indicates that
for Monday through next Wednesday the weather pattern could be
warm and dry or cooler and wetter. -IG

&&

.AVIATION...
20/00Z TAF Period

Scattered rain showers across North Central and Central Montana
airfields continue through at least 2z this evening, primarily being
vicinity showers but a few could reach the KHLN, KGTF, and KLWT
airports during the beginning of the TAF period. A few scattered
showers have had embedded thunder with them and primary concerns
with them have been lightning and a brief heavy downpour with low
ceilings. After 2z, shower activity begins to decrease for the
evening. KGTF has low probability (10%) of developing fog tomorrow
morning so forecast confidence is low to include in the TAFs this
forecast period, but southwest Montana valleys could develop some
isolated patchy fog in the early morning hours bringing a brief
reduction in visibility to less than 6 miles. Webb

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

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  40  74  50  77 /  10  10  10  60
CTB  37  72  45  73 /  20  20  10  70
HLN  44  79  53  83 /  20  10  10  40
BZN  38  76  47  80 /   0  10  10  30
WYS  29  71  38  75 /   0  10   0  20
DLN  37  74  44  81 /   0   0   0  10
HVR  43  78  52  77 /  10  10  20  80
LWT  40  71  48  73 /  20  30  20  80

&&

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

$$

http://www.weather.gov/greatfalls