mt discuss
Office: TFX
FXUS65 KTFX 281108
AFDTFX
Area Forecast Discussion
National Weather Service Great Falls MT
508 AM MDT Sun Apr 28 2024
Updated Aviation Discussion
.SYNOPSIS...
Drier and breezy conditions are expected today under a westerly
flow aloft. The unsettled weather pattern resumes on Monday as a
cold front crosses the region with gusty winds, showers a few
thunderstorms. A potentially colder and wetter system moves
through the area Tuesday night Wednesday with an overall unsettled
weather pattern persisting through the upcoming week.
&&
.DISCUSSION...
Early morning satellite imagery shows an unseasonably deep trough
in the Gulf of AK with upper level jet to its south approaching the
west coast. Flow splits downstream with a weaker shortwave lifting
out across MT while the rest of the energy tracks across the SW US
into an upper level system lifting out into the central US plains.
Showers associated with the northern disturbance have largely moved
east of the area with generally dry conditions expected across the
area today as westerly flow overspreads the area. Still, there is
enough residual moisture in the flow and weak instability to maintain
some isolated to widely scattered showers across the mountains of
western and southwest MT. Some patchy fog has developed this morning
across portions of north-central MT including Havre, Ft Benton
and Lewistown and this should dissipate fairly quickly after
sunrise as westerly winds surface across the plains this morning.
The incoming upper jet and initial shortwave moving out of the
Gulf of AK trough reach the Northern Rockies Monday with a cold
front shifting east across most of the area by Monday evening.
Larger scale ascent and some modest instability should support a
fairly widespread coverage of showers and a few thunderstorms
Monday afternoon across areas roughly along and southeast of a
line from Lincoln to Great Falls and Havre. Precipitation amounts
of 0.25" or more are most likely (50-70% probability) across
eastern portions of central/SW MT (Judith Basin, Fergus, Meagher
and Gallatin counties) where probabilities for thunderstorms are
also around 50-70%. These areas could also see some stronger wind
gusts (35-45 mph) with any storms that develop due to the more
favorably timed late afternoon frontal passage. Gusty west to
northwest winds spread across most of the area behind the front
Monday night and continue through Tuesday as surface low pressure
develops in southern Saskatchewan to the north of a mid level
circulation tracking east along the international border.
The Tuesday night through Wednesday period continues to hold some
potential for winter weather impacts as another shortwave moves
through the trough and pivots an area precipitation west and
southwestward from southern Saskatchewan and Alberta. This
initially affects areas near Glacier NP by Tuesday night with most
model ensemble members (80%) eventually wrapping some of this
precipitation southward through much of north-central MT
Wednesday. Probabilities for snowfall accumulation in excess of 4
inches are greatest across western portions of Glacier county
(50-60%) while probabilities for 2" or greater snowfall
accumulation now range from 50-60% across many of the central and
southwest MT mountain ranges with a 30% chance of snow
accumulation exceeding one inch for areas from Cut Bank to Great
Falls and Lewistown. In addition to the potential for wet
snowfall, daytime temperatures will be much colder (30s to around
40) with gusty northwest winds also likely through early
Wednesday. The overall active weather pattern is likely to persist
into next weekend with a break and some warming on Thursday
before the next round of unsettled weather moves in late this week
into the weekend. Hoenisch
&&
.AVIATION...
508 AM MDT Sun Apr 28 2024 (28/12Z TAF Period)
Lower clouds and a few light showers as well as some patchy fog
linger through early this morning near KEKS and KBZN where mainly
MVFR conditions are expected before conditions improve to VFR after
15z. Some fog also remains in the KHVR area this morning with
improvement by 15z. Otherwise, mainly VFR conditions prevail across
the remainder of north-central and southwest MT with breezy westerly
winds developing by this afternoon at most terminals. Hoenisch
Refer to weather.gov/zlc for more detailed regional aviation weather
and hazard information.
&&
.PRELIMINARY POINT TEMPS/POPS...
GTF 60 39 54 34 / 0 10 70 20
CTB 57 35 53 31 / 0 0 10 10
HLN 61 38 55 32 / 0 20 90 20
BZN 60 35 58 24 / 40 20 100 70
WYS 49 28 48 18 / 80 30 90 70
DLN 56 35 55 24 / 20 10 90 30
HVR 65 38 62 34 / 0 0 30 30
LWT 58 37 55 28 / 10 20 100 70
&&
.TFX WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
http://www.weather.gov/greatfalls
Office: MSO
FXUS65 KMSO 280809
AFDMSO
Area Forecast Discussion
National Weather Service Missoula MT
209 AM MDT Sun Apr 28 2024
.DISCUSSION...Low pressure spinning over the Gulf of Alaska is
pushing Pacific moisture into the northwestern U.S. this morning
while another low departs the Rocky Mountain West and enters the
Great Plains. The Northern Rockies will be between these systems
for a short period of time today. Southwest Montana and Lemhi
County will get a short break in precipitation while the Pacific
system moves closer. In the meantime, northwest Montana, along
with Clearwater and Idaho Counties, will see continued
precipitation in the form of lower elevation rain and high
elevation (above about 5000 ft) snow today. A cold front
associated with this system will bring some increasing westerly or
southwesterly winds this afternoon ahead of the frontal passage.
By Monday, the low will arrive in the Pacific Northwest.
Continued frontal dynamics, along with Pacific moisture and a
favorable position of the upper level jet will result in moderate
precipitation focused on north-central Idaho and the southern
Bitterroot Valley. Snow levels will lower to around 3800-4500 feet
in these locations. Locations like Elk City, Dixie, Lolo Pass, and
Lost Trail Pass could receive 1 to 3 inches of wet snow, while
higher elevations of the Clearwater, Bitterroot, Anaconda, and
Pintler Mountains could receive 6 to 12 inches of snow.
The unsettled and cool pattern continues through the first week
of May. Tuesday through Wednesday, a back door cold front will
affect the Continental Divide as a closed low forms on the east
side. Wraparound moisture from this system will be conducive to a
spring snow event for the Glacier Park region and the Divide to
include Marias Pass, where there is about a 50% chance of seeing 4
or more inches of snow by Wednesday evening.
&&
.AVIATION...A break in shower activity this morning will make fog
a good possibility at KMSO. Otherwise, expect a mostly overcast
day with decreasing shower activity and increasing westerly or
southwesterly winds with gust to about 20 kts this afternoon.
Showers will become more widespread again tonight, especially over
the terrain along the Idaho-Montana border.
&&
.MSO WATCHES/WARNINGS/ADVISORIES...
MT...None.
ID...None.
&&
$$
Office: BYZ
FXUS65 KBYZ 280825
AFDBYZ
Area Forecast Discussion
National Weather Service Billings MT
225 AM MDT Sun Apr 28 2024
.DISCUSSION...
Today through Monday...
Satellite imagery shows a dynamic low in the central plains and a
zonal flow moving thru the PacNW and northern Rockies. There are a
couple of embedded weak shortwaves. The first is helping to
produce scattered light showers over western areas currently, and
is also associated with a shift to westerly winds. The other wave
moving from WA/OR into ID will provide very modest ascent for
shower activity later today. As surface winds turn to the NW over
the next several hours, focus of showers from late morning til
evening will evolve to our southern upslope areas. None of this
precip will be heavy, and diurnal instability is too marginal for
a mention of thunderstorms today. Mountains will pick up a little
snow, on the order of a half inch to 2 inches. The probability of
exceeding 2" over the next 24 hours is only 30% over the
Beartooths. Temps today will again be seasonable with highs in the
upper 50s to mid 60s.
Before moving to Monday, we should point out there is advection of
stratus approaching far southeast MT from western SD. Look for a
fog/stratus combo in Carter County over the coming hours, and
boundary layer moisture may even be deep enough to produce pockets
of upslope drizzle over the hills. Something to watch if you're
traveling in the Alzada and Ekalaka areas thru maybe 15z this
morning.
Downslope/pre-frontal warming will exist on Monday ahead of a
stronger Pacific shortwave, and SW winds will become breezy (gusts
30-40 mph expected along western foothills). High temps should
range from 60-70F, warmest over central and east parts. A few
showers may spread over our western mountains/foothills in the
morning, but the much better chances of showers (50-90%) will be
in the afternoon as large scale ascent increases from the west.
Dew points in the low-mid 30s will limit instability but sbcapes
should reach 100-300 j/kg, so we may see a few weak thunderstorms
near the cold front, which isn't expected to reach our west until
close to 00z. The cold front/convection combo has the potential to
produce gusty winds (up to 45 mph) by late in the day, starting
in our west of course. Something to watch if you have outdoor
plans late Monday afternoon & evening.
JKL
Monday evening through Saturday...
An unsettled pattern with several shortwaves and troughing is
in store for much of the week. Chances for precipitation are
ubiquitous, the highest chances will be see on Monday as a cold
front moves through Montana. The best chances for precipitation
through Tuesday will be west of a Miles City to Sheridan line.
Locations west of this line have a 50-80% chance of at least 0.1"
of QPF in this period. The western mountains will have the highest
precip probabilities through the extended forecast, with a few
inches of snowfall expected. While precipitation for lower
elevations will be mostly rain, snow levels are going to drop to
around 3000ft Monday night bringing chances for some light snow
accumulations. Locations such as Red Lodge have up to a 15% of an
inch of snow, while the mountains will have a 50-80% chance of at
least 2 inches.
Models depict another wave pushing across the region Wednesday
night, with some slightly increased moisture chances, 20-50% for
lower elevations and 50-70% in the mountains. For the rest of the
week, PoPs of 20-40% are in the forecast. From Monday night
through Thursday night, the mountains have a 40-70% chance of
picking up 6 inches of snow.
With the passing cold front, breezy winds of 20-40 mph will be
felt across the area through Tuesday. The highest gusts in the
30s-40s mph will be in the far east, along the Dakota borders.
Highs in the 50s to low 60s through Friday, before potential 70s
on Saturday.
Matos
&&
.AVIATION...
Scattered light showers will impact areas west of KMLS-K00F today
and tonight. VFR will be dominant, but local MVFR is possible
especially near the foothills. Mountains will be frequently
obscured in snow showers. There is also a moderate risk (50%
chance) of fog/stratus in far southeast MT (KBHK-K97M) thru 15z
this morning. Local MVFR-IFR is expected in this area. JKL
&&
.PRELIMINARY POINT TEMP/POPS...
Tdy Mon Tue Wed Thu Fri Sat
-------------------------------------------------------
BIL 063 043/067 038/056 036/056 036/057 037/059 037/064
2/W 25/T 72/W 24/W 35/W 24/W 32/W
LVM 059 039/061 029/049 028/049 030/054 033/055 034/061
5/W 29/T 84/J 35/W 34/W 25/T 32/W
HDN 066 039/070 037/059 034/058 035/057 035/062 037/065
2/W 23/W 92/W 24/W 45/W 24/W 32/W
MLS 065 039/068 040/057 036/056 036/055 036/060 038/061
1/B 01/B 81/N 13/W 23/W 23/W 32/W
4BQ 064 038/068 040/057 035/058 036/053 035/059 037/061
1/B 01/B 41/N 12/W 34/W 23/W 32/W
BHK 058 033/068 037/057 033/056 033/053 032/057 034/058
0/B 00/U 61/N 13/W 24/W 23/W 32/W
SHR 062 037/068 034/057 029/056 031/052 030/057 033/061
3/W 22/W 82/W 23/W 55/W 34/W 42/W
&&
.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...None.
WY...None.
&&
$$
weather.gov/billings
Office: GGW
FXUS65 KGGW 280901
AFDGGW
Area Forecast Discussion
National Weather Service Glasgow MT
301 AM MDT Sun Apr 28 2024
.DISCUSSION...
KEY MESSAGES:
1) For the 24-hour period ending at 6 AM Tuesday, there is a
80-90% chance of a wetting rain (at least 0.1 in) for most of
northeast Montana. The chance for at least 0.25 in and 0.5 inches
of rainfall for the same period maxes out at 50-70% and 20-40%
chance, respectively.
2) Winds pick on Tuesday, with gusts as high as 45 to 50 mph
possible.
3) Tuesday and Wednesday, area of precipitation moves north of the
Missouri River as high pressure builds across southern Montana in
the wake of the surface low pressure system passage.
WEATHER PATTERN OVERVIEW:
A shortwave trough moving through this morning will provide
chances for precipitation in our western zones, but diminish as
this area moves west through the day. Then, an upper level trough
moves in across the areas, bringing chances for precipitation
through at least Tuesday for northeast Tuesday, as described
probabilistically above.
From Tuesday, a shortwave ridge aloft builds and moves across
southeast MT, resulting in surface high pressure moving areas of
precipitation generally north of MT Hwy 200. As the high pressure
builds to the south, a tight pressure gradient develops from
northwest MT into eastern Montana. This increases winds speed,
mainly south of the Missouri River, with a medium to high chance
for at least 40 mph gusts, but low chance (<20%) for gusts in
excess of 55 mph. Given this, not issuing any wind headlines at
this moment, but will discuss with the next shift as we could
likely issue the Lake Wind Advisory on their shift. Discussion
regarding fire weather headlines is provided in the Fire Weather
Forecast. Chances for precipitation shifts north thanks to this
surface high pressure influence from the south. The chances for at
least 0.25 inches for the period from Tuesday through Wednesday
ranges from 30 to 50% for areas north of the Hi-Line.
From Thursday, the trough fills and moves into the Great Plains,
placing the region in northwest flow aloft, resulting in chances
for daily afternoon showers.
CONFIDENCE AND POTENTIAL DEVIATIONS FROM BASE FORECAST:
NBM has tended to underestimate the last few wind events across
the region, so will have to monitor the next run to see if the
winds for Tuesday increase. This will dictate headline decisions.
-Enriquez
&&
.AVIATION...
LAST UPDATED: 0900Z
FLIGHT CAT RANGE: VFR (MVFR in isolated shower) today. MVFR from
Monday morning
DISCUSSION: Morning showers along the island ranges of central and
eastern Montana will move east this morning, diminishing as they
do so. Monday, rain showers move in from south central Montana
moving northeastward through the day.
-Enriquez
&&
.GGW WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
weather.gov/glasgow
