Area Forecast Discussion
Issued by NWS Great Falls, MT

Home | Current Version | Previous Version | Text Only | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
FXUS65 KTFX 180459

Area Forecast Discussion
National Weather Service Great Falls MT
1059 PM MDT Thu Aug 17 2017



The Red Flag warning in effect for this evening has been
cancelled. Winds are light and humidity is rising above 20
percent. Minor adjustments were applied to bring hourly
observations in line with observed trends for the rest of this

Shortwave ridging on Friday will bump temperatures a few
degrees warmer than today, and push minimum relative humidity
lower. Boundary layer mixing will add gusty winds through the
afternoon. Surface low pressure developing over southern Alberta
Friday night will help maintain gusty winds, which in turn will
inhibit overnight recovery of relative humidity. Hence, the Red
Flag Warning remains in effect for Friday and Friday night. PN


Mostly dry and warm conditions can be expected over the entire
region tonight, continuing through the weekend. Afternoon highs
will generally be in the 80s to near 90. Areas of smoke will
affect the region as well through the upcoming weekend.


Updated 0600z.

VFR conditions will again prevail over the region through the
period...except for areas of smoke...which could create some MVFR
conditions. The smoke will affect areas from just north of KGTF
southward to KHLN and KBZN. Visibility could be reduced from 4 to
6 miles at times...perhaps bringing some MVFR conditions.
Confidence is low that vis may reduce to MVFR have
mainly left out mention of smoke at this time. Will have to
continue to monitor for its addition through the forecast period.
Distant mountains could be obscured at times. Otherwise expect VFR
conditions with a few mid to upper level clouds across most sites
tonight. Mainly clear skies and some increased westerly winds are
then expected for Friday. Anglin


Widespread critical fire weather conditions are expected Friday
and Friday Night due to low humidity and gusty winds. Winds are
likely to remain strong Friday night with poor overnight recovery
of relative humidity. Fires could remain active throughout the
night on Friday.

Additionally fire weather highlights are possible Saturday through
the early portions of next it will remain warm and dry
with low humidity.


/ISSUED 536 PM MDT Thu Aug 17 2017/

Tonight through next Thursday...Overall very little change in the
forecast for the next few days. Above normal temperatures with low
humidity and breezy afternoon/evening winds expected in most
areas. Little to no precipitation is expected through much of the
period. The only changes I made from the national blend models was
to add a slight chance of storms on Monday, mainly over the
central mountains as a weak upper level disturbance moves
southward through the flow aloft. On Wednesday afternoon/evening I
also increased pops a bit as the GFS model progs an upper level
disturbance moving northward into southwest MT.

I did add areas of smoke for tonight through Friday morning along
the divide and then along the I-90 corridor area from Boulder to
Bozeman...but this will continue to be updated as necessary.


GTF  55  91  54  84 /   0   0   0   0
CTB  53  85  51  78 /   0   0   0   0
HLN  55  90  56  88 /   0   0   0   0
BZN  49  87  50  87 /   0   0   0   0
WEY  40  76  39  77 /   0   0   0   0
DLN  48  85  49  85 /   0   0   0   0
HVR  52  92  53  82 /   0   0   0   0
LWT  50  88  53  82 /   0   0   0   0


Red Flag Warning from noon Friday to 6 AM MDT Saturday Central
and Eastern Lewis and Clark National Forest Areas...Chouteau and
Fergus Counties...Deerlodge/Western Beaverhead National Forest...
Eastern Glacier/Toole/Central/Eastern Pondera/Liberty...Helena
and Townsend Ranger Districts of the Helena National Forest...
Hill and Blaine Counties...Lewis and Clark National Forest Rocky
Mountain District-Rocky Mountain Front...Lincoln Ranger District
of the Helena National Forest.


$$ is the U.S. government's official web portal to all federal, state and local government web resources and services.