276
FXUS65 KTFX 082048
AFDTFX

Area Forecast Discussion
National Weather Service Great Falls MT
248 PM MDT Wed May 8 2024

.SYNOPSIS...

Snow and rain will end from northeast to southwest by Thursday
morning. Across North-central and Central Montana patchy dense fog
is possible this evening through Thursday morning in areas where
skies clear. North-central, Central, and Southwestern Montana
will dry out and warm up Thursday afternoon through the weekend.
By the middle of next week the weather pattern could change.

&&

.DISCUSSION...

This afternoon through Thursday... Rain/snow will
continue through the evening along the Highway 200 Corridor and
south. Precipitation will end from northeast to southwest by
Thursday morning. There will also be isolated rain showers across
North-central Montana through this evening. Snow will continue
along the Southern Rocky Mountain front through this evening.
Patchy dense fog has formed in Northern and Central Fergus County
and will continue through Thursday morning. At times visibility
will be reduced to a quarter mile or less. Patchy dense fog could
form in other locations of Central and North-central Montana if
skies clear overnight due to all the moisture from this system. A
Winter Weather Advisory has been issued for the Madison River
Valley and Gallatin Valley until midnight due to snowfall reducing
visibility down to a half mile at times. The Blizzard Warning for
the Little Belts and Highwood Mountains has been downgraded to a
Winter Storm Warning due to the strong winds and wind gusts having
ended. The snow has ended for the Highwood Mountains. The Winter
Storm Warning along the Northern Rocky Mountain front has been
cancelled due to the snow having ended. The Winter Storm Warning
along the Southern Rocky Mountain Front has been downgraded to a
Winter Weather Advisory. For more details see the TFX
WATCHES/WARNINGS/ADVISORIES section below. On Thursday an upper-
level trough begins to move out of the area. This will begin to
warm up and dry out North-central, Central, and Southwestern
Montana.

Friday through Sunday... On Friday an upper-level ridge begins to
move over North-central, Central, and Southwestern Montana. This
will warm temperatures up to about seasonal averages across the
area. This upper-level ridge will stay in place above North-central,
Central, and Southwestern Montana through the weekend which will
keep temperatures dry and allow temperatures to warm up to above
seasonal averages across the area through the weekend. Isolated
locations of North-central and Central Montana and the Helena Valley
have a 50 - 65% chance for having temperatures of 80 degrees or
warmer.

Monday through next Wednesday... On Monday cluster analysis
indicates that there will be upper-level zonal flow over North-
central, Central, and Southwestern Montana. This will keep the
area`s weather about the same on Monday as Sunday. On Tuesday three
clusters (86% of ensemble members) have a week upper-level trough
over North-central, Central, and Southwestern Montana. One of the
clusters (14% of ensemble members) has an upper-level ridge over
North-central, Central, and Southwestern Montana. This indicates
that the weather pattern could change on Tuesday. Next Wednesday the
ensembles begin to diverge and so the weather over North-central,
Central, and Southwestern Montana is uncertain at this time. -IG

&&

.AVIATION...
1220 PM MDT Wed May 8 2024 (08/12Z TAF Period)

Widespread rain and snow will affect Central ad Southwest MT into
the evening hours. IFR or lower conditions will also occur.
Conditions slowly improve overnight, as the showers become more
scattered. However, with any clearing, there is the possibility that
some fog could develop. Overall, mostly VFR conditions are expected
by 18z Thu for most areas. Mountains/passes will be obscured through
late Thu morning. Brusda

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

&&

.HYDROLOGY...

The flood warning will continue for Clear Creek, as the creek has
risen into major stage earlier today.

Additional runoff from the Bears Paw Mountains will continue to
produce minor flood impacts from other small streams and creeks,
such as Big Sandy Creek and Beaver Creek. Areas of minor flooding
have been reported around Beaver Creek, along with locations around
Hays and Lodge Pole. Thus the areal flood advisory will continue for
portions of North Central MT until Thursday afternoon.

For areas further south and west, most of the higher elevations have
had just snowfall recently, thus runoff from the recent snowfall
will begin in a few days as warmer air moves back in. Since most
river levels are currently low, impacts should be minor from any new
flooding that develops. Brusda



&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  34  56  34  64 /  80  40   0   0
CTB  31  59  33  70 /  10   0   0   0
HLN  40  58  37  70 /  60  30   0   0
BZN  34  55  31  64 /  70  50  10   0
WYS  30  53  26  61 /  40  30   0   0
DLN  37  56  34  66 /  50  20   0   0
HVR  41  66  38  70 /  40  20   0   0
LWT  32  48  31  58 /  90  50  10   0

&&

.TFX WATCHES/WARNINGS/ADVISORIES...
Winter Weather Advisory until midnight MDT tonight for Southern
Rocky Mountain Front.

Winter Storm Warning until midnight MDT tonight for Big Belt,
Bridger and Castle Mountains-Gallatin and Madison County
Mountains and Centennial Mountains-Snowy and Judith Mountains.

Winter Weather Advisory until midnight MDT tonight for Gallatin
Valley-Madison River Valley.

Winter Storm Warning until midnight MDT tonight for Little Belt
and Highwood Mountains.

&&

$$

http://www.weather.gov/greatfalls