mt discuss
Office: TFX
FXUS65 KTFX 172059
AFDTFX
Area Forecast Discussion
National Weather Service Great Falls MT
259 PM MDT Wed Jul 17 2024
.SYNOPSIS...
Isolated thunderstorms are expected this evening, mostly south of
a line from Great Falls to Lewistown. On Thursday, expect a few
more thunderstorms during the afternoon and evening hours,
especially in the Havre and Lewistown areas. Otherwise, above
normal temperatures will continue through the upcoming weekend and
into next week.
&&
.DISCUSSION...
Tonight through Thursday...Isolated thunderstorms are expected
through this evening, with a redevelopment of scattered
thunderstorms on Thursday. Some of the stronger storms will
produce gusty winds, hail and frequent lightning. An isolated
severe storm is also possible. Otherwise above normal temperatures
will continue.
For Friday through Wednesday, expect the trend of above normal
temperatures to continue. Overall, most lower elevation locations
will have afternoon highs ranging from the lower to upper 90s.
Little to no precipitation is expected for much of the early
portions of next week, as an upper level ridge will reside over
the CWA into the middle portion of next week. Brusda
&&
&&
.AVIATION...
17/18Z TAF Period
Mainly VFR conditions are expected across North Central and
Southwestern Montana today as warm and mostly dry conditions
persist. Watch for a few isolated SHRA/TSRA over the higher terrain,
along with some smoke from KHLN south. Warm temperatures will
result in high density altitude for some. Ludwig
Refer to weather.gov/zlc for more detailed regional aviation
weather and hazard information.
&&
.FIRE WEATHER...
Isolated thunderstorms are expected this evening, while scattered
thunderstorms are expected on Thursday. Expect a mix of dry and
wet thunderstorms. The main concern from any storms will be gusty
outflow winds and lightning that occurs away from the parent
storms. Brusda
&&
.PRELIMINARY POINT TEMPS/POPS...
GTF 63 93 60 93 / 0 20 10 0
CTB 60 89 55 92 / 10 20 10 0
HLN 64 98 62 97 / 10 20 10 10
BZN 58 95 57 93 / 0 20 10 10
WYS 45 84 44 84 / 10 30 10 20
DLN 56 91 54 89 / 20 10 0 10
HVR 63 94 59 94 / 0 20 50 10
LWT 59 90 55 87 / 20 30 30 10
&&
.TFX WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
http://www.weather.gov/greatfalls
Office: MSO
FXUS65 KMSO 171841
AFDMSO
Area Forecast Discussion
National Weather Service Missoula MT
1241 PM MDT Wed Jul 17 2024
.DISCUSSION...Moisture circulating around a low pressure system
in Oregon and Washington will shift into Idaho and western Montana
today. So far, lightning has been observed in eastern Oregon and
eastern Washington, with the potential for lightning to occur as
it moves inland this afternoon. That being said, the amount of
high-based (vertically integrated) wildfire smoke, and near-
surface wildfire smoke, will present a challenge and could inhibit
convective development. If it does so, that would mean less of a
potential for lightning throughout the day today as smoke
stabilizes the atmosphere. The one area with less smoke in the
air is northwest Montana, which is where instability will be
greatest as we head into the evening and overnight hours. Because
of this, northwest Montana stands a much better chance of
receiving thunderstorms with little precipitation, and an
increased chance for lighting, overnight tonight as the low moves
through. Gusty winds will accompany thunderstorm and shower
activity, with widespread gusty winds of 20 to 25 mph expected
throughout the day Thursday.
Keeping the regional smoke in mind, forecast models show additional
high-based smoke ushering into the Northern Rockies from the west
and southwest Thursday through the weekend. With the
reamplification of the high pressure ridge expected Friday through
Sunday, it is likely the smoke will remain in the forecast and
have an impact on how hot temperatures become over the weekend.
There are two scenarios that could play out regarding this
weekend's heat:
Scenario 1: Smoke will thin enough to allow for maximum heating
potential across central Idaho and western Montana. If this
happens, we could see some of the hottest daytime temperatures of
the season so far for many valley locations of both central Idaho
and western Montana. And in some cases, all time record highs
could be in jeopardy.
Scenario 2: Smoke continues to thicken, or remains thick enough,
to inhibit the full heating potential across the region. This
would cause temperatures to be about 10 to 20 degrees cooler than
the maximum potential in the forecast.
We'll be keeping a very close eye on this. In the meantime,
continue to take care of yourself and others, especially those
with sensitivity to extreme heat.
By mid next week, the high pressure ridge looks to break down,
allowing for more unsettled weather in the form of thunderstorms
and possible showers, along with lightning and gusty winds. Cooler
temperatures are also likely to follow.
&&
.AVIATION...Smoke from regional and local wildfires will create
hazy skies and localized visibility reductions. A spoke of energy
ahead of the low-pressure center off the Oregon coast is forecast
to pass through the region later today, bringing the threat of
gusty winds and lightning through tonight. The main focus for
storms overnight will be in northwest Montana. Smoke will continue
to impact visibility through the day Thursday, with breezy west
winds of 20 knots to persist after 18/1800Z.
&&
.MSO WATCHES/WARNINGS/ADVISORIES...
MT...None.
ID...None.
&&
$$
Office: BYZ
FXUS65 KBYZ 171930
AFDBYZ
Area Forecast Discussion
National Weather Service Billings MT
130 PM MDT Wed Jul 17 2024
.DISCUSSION...
Through Thursday Night...
Satellite imagery shows a ridge axis over central MT and an
upstream weak low over western WA/OR. As expected, we are
beginning to see convection develop over the mountains with
lightning noted south of Cooke City and Sheridan as of 1pm. There
is nothing yet over the Crazies or Snowies, but as the ridge axis
migrates to the east and the air mass moistens a bit more this
should begin to happen over the next few hours (especially given
upslope SE winds from the surface to 700mb). Overall, convection
between now and about 10pm will be weak but may produce erratic
surface winds to about 40 mph. Greatest potential is near the
mountains/foothills but some activity may spread eastward to
include Roundup & Billings this evening. High res models have been
fairly consistent in this regard.
Late tonight and Thursday morning will be dry, then by afternoon
we begin to see the effects of the approaching Pacific low. The
low will crest the ridge and not induce height falls, and flow
aloft will remain quite weak, but the ascent along with a bit
moister air mass (pwats ~0.90") will result in a much greater
potential (30-50% probability) for thunderstorms tomorrow
afternoon and evening across the region. HREF shows only a modest
signal for convective winds, but forecast soundings are somewhat
indicative of wet microbursts and so gusty outflow winds will need
to be watched. Wind shear will be too low and mid levels too warm
for a risk of anything but wind and localized downpours. As the
PV anomaly tracks from north central thru southeast MT, the chance
of showers & thunderstorms will persist over our east thru
tomorrow night.
Regarding fire weather, the increased lightning activity on
Thursday may be problematic given our drying fuels, but the storms
will be wet and there is a reasonable expectation of localized
wetting rains...including during the nighttime hours in southeast
MT.
Temps of course will remain warmer than normal. Look for highs
Thursday in the 90s most places but a few notorious hot spots
could touch 100F as 700mb temps rise to near +14C.
JKL
Friday through Wednesday...
Upper ridge axis will be over W. MT on Friday, while NW flow
brings shortwave energy SSE through the eastern part of the
forecast area. In addition...other shortwaves will move through
the remainder of the area, while monsoonal moisture continues over
the region. PWAT's will be just over an inch in the far E. Thus
there is a 20% chance of showers and thunderstorms in the morning
from KMLS E and SE. Chances for showers and thunderstorms will
increase from Rosebud County E in the afternoon with highest
chances on the MT/Dakotas border at 40 to 50%. Southern mountains
will have 30-40% PoPs and there will be slight chances (20%) over
KSHR and over areas near the western mountains. Low PoPs linger in
the evening over the SW mountains and far SE MT. The best chances
for 0.25 inches or higher of rainfall through Fri. evening will be
E and SE of KMLS in the teens to around 20%.
Region will be under upper ridging Saturday through Tuesday with
continued monsoonal moisture over the area. Expect 20-30% chances
for showers and thunderstorms over the SW mountains and the NE
Bighorns for the weekend each afternoon. Low afternoon/evening
chances continue over the SW mountains through Tuesday. Models
showed a trough approaching the area from the W on Wednesday with
low PoPs over the western mountains spreading into adjacent areas
including KLVM, K6S0 and Judith Gap. Mean 700 mb temp was 16 degs
C which could cap lower elevation convection, but this was way out
in time in the forecast period, so will continue to watch model
trends.
As for temperatures, highs will be in the upper 80s to low/mid 90s
Fri. through Monday, then in the 90s on Tuesday and in the 90s to
around 100 on Wednesday. There was a 30-50% chance of reaching 100
degrees in the river valleys on Wed. and this area included KBIL,
KMLS and KSHR. KMLS will be close to record temps if this scenario
plays out. Arthur
&&
.AVIATION...
VFR conditions will prevail over the next 24 hours, though slant
range visibility will be reduced at times due to the numerous
wildfires over the western U.S. Isold/Sct thunderstorms expected
mainly over and near mountains thru 04Z this evening.
Thunderstorms have a 10-20% chance of impacting KLVM-KSHR, and a
<10% chance at KBIL. Storms have the potential to produce briefly
erratic surface winds. There is a greater risk of thunderstorms
(plus erratic surface winds and local MVFR) Thursday afternoon &
evening, and all TAF sites may be impacted. JKL
&&
.PRELIMINARY POINT TEMP/POPS...
Thu Fri Sat Sun Mon Tue Wed
-----------------------------------------------------------
BIL 063/097 064/094 065/093 063/091 062/093 063/095 064/099
22/T 41/U 11/U 01/U 00/U 00/U 01/U
LVM 056/094 054/094 057/093 055/091 055/091 054/095 057/097
23/T 22/T 11/U 01/U 01/U 01/U 12/T
HDN 060/099 062/095 062/093 060/092 059/093 059/097 060/100
22/T 41/U 11/U 11/U 00/U 00/U 00/U
MLS 064/096 068/091 063/090 064/089 064/090 064/094 066/097
00/U 43/T 11/U 11/U 00/U 00/U 00/U
4BQ 063/097 066/092 063/089 061/087 061/090 063/094 064/097
00/U 33/T 10/U 01/U 00/U 00/U 00/U
BHK 060/094 063/088 060/087 058/086 059/088 059/092 060/094
00/U 44/T 11/U 11/U 10/U 00/U 00/U
SHR 056/098 059/093 057/090 056/087 055/090 056/093 058/095
22/T 22/T 11/U 11/U 01/U 00/U 01/U
&&
.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...None.
WY...None.
&&
$$
weather.gov/billings
Office: GGW
FXUS65 KGGW 171919
AFDGGW
Area Forecast Discussion
National Weather Service Glasgow MT
119 PM MDT Wed Jul 17 2024
.DISCUSSION...
KEY MESSAGES:
- Mostly dry conditions with above average temperatures will
continue.
- Isolated thunderstorms tonight in Garfield and Petroleum
counties, then scattered thunderstorms Thursday evening for
northeast Montana.
- Scattered haze from Canadian wildfires is expected to sneak
into the area the next couple days.
WEATHER PATTERN OVERVIEW:
A surface stationary front will hang over central Montana through
Friday, which will aid in a thunderstorm initiation off the high
terrain of the Big Snowies this evening as well as tomorrow. Very
little support exists for thunderstorm maintenance in Petroleum
county, but may produce a brief wind gust to 40 mph. Then
tomorrow, a shortwave trough will help sustain longer-lived
thunderstorms. With rather warm temps and dewpoints mainly in the
40s, high based tstorms are expected to initiate in the late
afternoon and move into northeast MT after 6 PM Thursday. Inverted
V profiles and steep lapse may help mix down wind gusts to near
severe limits, especially when the storms begin to die out.
Friday and Saturday are expected to feature isolated thunderstorms
each afternoon as the stationary front shifts eastward. Very
little wind shear (below 30 knots bulk shear from 0 to 6 km) will
support these storms, but a well mixed atmosphere and enough
surface moisture, especially closer to the ND border, will be
enough of a forcing to get small storms to initiate.
The GFS ensemble and climate prediction center are both suggesting
temperatures to remain above normal for the remainder of the
long-distance forecast. Any precipitation that does occur will be
isolated and associated with shortwave troughs. However,
confidence on precipitation occurring at all is low at this time.
FORECAST CONFIDENCE & DEVIATIONS:
High confidence of the ridge intensifying to bring temperatures
back up to above normal over the next few days. Medium confidence
on thunderstorm chances Wednesday evening and late Thursday
afternoon into early Friday morning. Low confidence on
precipitation amounts due to the spotty and scattered nature of
the thunderstorms.
-Bernhart/Stoinskers
&&
.AVIATION...
FLIGHT CONDITION: VFR, then possible MVFR after 00Z Friday
DISCUSSION: Dry conditions will continue through tomorrow
afternoon. There will be scattered hazy conditions caused by
residual wildfire smoke filtering in from Canada though. Late
Thursday evening will feature scattered showers and thunderstorms,
which may bring erratic, gusty winds with them.
WINDS: East at 5 to 10 knots.
&&
.GGW WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
weather.gov/glasgow
