994
FXUS65 KTFX 300925
AFDTFX

Area Forecast Discussion
National Weather Service Great Falls MT
325 AM MDT Mon Sep 30 2024

.SYNOPSIS...

Below normal temperatures today will warm back above normal for
the day on Tuesday as southwest to west surface winds increase.
Dry conditions are generally expected through the upcoming work.

&&

.DISCUSSION...

Today through Tuesday...below normal temperatures and overall lighter
winds are expected across Southwest through North Central Montana
today in wake of a cold front; however, breezy and gusty winds will
still be experienced through the afternoon hours across eastern
portions of Central and North Central Montana (generally east of a
Havre to Stanford line). By tonight, increasing cross barrier flow
and a strengthening surface pressure gradient along the Rocky
Mountain Front and Central Montana mountains will lead to increasing
southwest to west surface winds at these locations, with breezy and
gusty winds then overspreading all of Southwest through North
Central Montana on Tuesday as a warm front lifts northeast and over
the region. These breezy and gusty winds on Tuesday will help
temperatures to warm into the 70s across lower elevations, which
will be some 5 to 10 degrees above normal. While high winds are not
currently expected on Tuesday, most of the plains of Central and
North Central Montana have a 50% or great chance of exceeding 40 mph
(gusts); with even a 50-70% chance of exceeding 55 mph along the
immediate Rocky Mountain.

Wednesday through next Monday...ensemble clusters are in good
agreement through Thursday; with zonal flow over the Northern
Rockies on Wednesday transitioning to northwesterly flow by Thursday
as ridging amplifies over the Pacific Northwest. This upper level
pattern combined with a weak, surface cold front dropping south from
Canada through Wednesday morning and then high pressure settling in
across the Northern Rockies for the day on Thursday will lead to
near normal temperatures and overall dry conditions for the days of
Wednesday and Thursday. Ensemble clusters begin to diverge further
and further each day from Friday through early next work week, with
some ensemble clusters suggesting upper level ridging amplifying and
persisting over the Western CONUS while others back to more of a
zonal pattern. Should upper level ridging amplify and persist over
the Western CONUS through this timeframe then above normal
temperatures and continued dry conditions would be favored; while
near normal temperatures and overall dry conditions (outside of the
Continental Divide where light precipitation would be possible at
times) would be favored within the zonal pattern. - Moldan

&&

.AVIATION...
30/06Z TAF Period

VFR conditions prevail this TAF period. The initial concern will be
for gusty winds across northern and eastern portions of the region
through much of the remainder of the night. A boundary dropping
south from Canada will result in a wind shift to a more northerly to
northwesterly direction for KCTB and KHVR, with limited confidence
in this shift occurring at KGTF and KLWT. Otherwise looking ahead to
daylight hours Monday, VFR conditions continue to prevail, with
breezy northwesterly winds persisting at KHVR and KLWT through the
day, while winds are lighter elsewhere. -AM

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

&&

.FIRE WEATHER...

Elevated fire weather concerns return to the plains of Central and
North Central Montana on Tuesday, especially across the grasslands,
as breezy and gusty downsloping winds help to push temperature above
normal as afternoon relative humidity values fall into the teens to
20s percent. While Hot, Dry, and Windy (HDWI) Indices look to
largely remain within the 75th to 90th Percentile of climatology on
Tuesday, portions of Fire Weather Zones 113 and 115 will eclipse the
95th Percentile. Given that these zones have seen well above normal
precipitation from rain events during the month of September we will
forgo a Fire Weather Watch at this time, but elevated concerns will
exist none-the-less. - Moldan

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  60  37  74  52 /  10   0  10   0
CTB  57  35  69  41 /  10   0  10  10
HLN  61  34  76  49 /   0   0   0   0
BZN  59  29  76  42 /   0   0   0   0
WYS  55  20  64  29 /   0   0   0   0
DLN  58  29  75  41 /   0   0   0   0
HVR  59  36  76  45 /  20   0   0  10
LWT  54  35  74  51 /  10   0   0   0

&&

.TFX WATCHES/WARNINGS/ADVISORIES...
High Wind Warning until 6 AM MDT early this morning for Bears
Paw Mountains and Southern Blaine-Fergus County below 4500ft-
Hill County-Judith Basin County and Judith Gap-Northern Blaine
County-Snowy and Judith Mountains.

&&

$$

http://www.weather.gov/greatfalls