Red Flag Warning 19, NWS Great Falls, MT

629 
WWUS85 KTFX 100723
RFWTFX

URGENT - FIRE WEATHER MESSAGE
National Weather Service Great Falls MT
123 AM MDT Sat Oct 10 2020

MTZ113-115-117-118-110200-
/O.CON.KTFX.FW.W.0019.201010T1800Z-201011T0200Z/
Hill and Blaine Counties-Chouteau and Fergus Counties-
Central and Eastern Lewis and Clark National Forest Areas-
Helena and Townsend Ranger Districts of the Helena National Forest-
123 AM MDT Sat Oct 10 2020

...RED FLAG WARNING REMAINS IN EFFECT FROM NOON TODAY TO 8 PM MDT
THIS EVENING FOR GUSTY WINDS AND LOW RELATIVE HUMIDITY FOR FIRE
WEATHER ZONES 113, 115, 117, AND 118...

* AFFECTED AREA...Hill and Blaine Counties, Chouteau and Fergus 
  Counties, Central and Eastern Lewis and Clark National Forest 
  Areas and Helena and Townsend Ranger Districts of the Helena 
  National Forest.

* WINDS...Southwest 20 to 30 mph, with gusts up to 45 mph.

* RELATIVE HUMIDITY...As low as 10 percent.

* IMPACTS...New fire ignition in low elevation grasslands may be 
  difficult to contain due to the strong winds, warm temperatures 
  and low humidity, creating favorable conditions for rapid fire 
  spread. The winds and low relative humidity will also create 
  challenges for the Yogo Fire containment efforts in the Little 
  Belt Mountains of zone 117.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A Red Flag Warning means that critical fire weather conditions are
either occurring now, or will shortly.  A combination of strong
winds, low relative humidity, and warm temperatures can contribute
to extreme fire behavior.

Please advise the appropriate officials or fire crews in these
areas of this Red Flag Warning.

&&

Moldan

$$

http://www.weather.gov/greatfalls

332 
WWUS85 KTFX 110145
RFWTFX

URGENT - FIRE WEATHER MESSAGE
National Weather Service Great Falls MT
745 PM MDT Sat Oct 10 2020

MTZ113-115-117-118-110245-
/O.EXP.KTFX.FW.W.0019.000000T0000Z-201011T0200Z/
Hill and Blaine Counties-Chouteau and Fergus Counties-
Central and Eastern Lewis and Clark National Forest Areas-
Helena and Townsend Ranger Districts of the Helena National Forest-
745 PM MDT Sat Oct 10 2020

...RED FLAG WARNING WILL EXPIRE AT 8 PM MDT THIS EVENING FOR GUSTY
WINDS AND LOW RELATIVE HUMIDITY FOR FIRE WEATHER ZONES 113, 115,
117, AND 118...

Winds remain moderately gusty this evening, but relative humidity
has risen above 25 percent at most reporting stations in the
warning area. As such, the Red Flag Warning will be allowed to
expire at 7 PM MDT.

$$

http://www.weather.gov/greatfalls

580 
WWUS85 KTFX 110147 CCA
RFWTFX

URGENT - FIRE WEATHER MESSAGE...CORRECTED
National Weather Service Great Falls MT
747 PM MDT Sat Oct 10 2020

MTZ113-115-117-118-110245-
/O.COR.KTFX.FW.W.0019.000000T0000Z-201011T0200Z/
Hill and Blaine Counties-Chouteau and Fergus Counties-
Central and Eastern Lewis and Clark National Forest Areas-
Helena and Townsend Ranger Districts of the Helena National Forest-
747 PM MDT Sat Oct 10 2020

...CORRECTED EXPIRATION TIME IN TEXT...

...RED FLAG WARNING WILL EXPIRE AT 8 PM MDT THIS EVENING FOR 
GUSTY WINDS AND LOW RELATIVE HUMIDITY FOR FIRE WEATHER ZONES 113, 
115, 117, AND 118...

Winds remain moderately gusty this evening, but relative humidity
has risen above 25 percent at most reporting stations in the
warning area. As such, the Red Flag Warning will be allowed to
expire at 8 PM MDT.

$$

http://www.weather.gov/greatfalls

Area Forecast Discussion
National Weather Service Great Falls MT
1100 PM MDT Thu Oct 8 2020

...Aviation Section Updated...

.SYNOPSIS...

A weak cold front moves through the region this evening for
diminishing winds overnight with cooler temperatures expected for
Friday. On Saturday, strong winds return ahead of a Pacific
system that will bring cooler than normal temperatures and an
increased chance for precipitation Saturday night through Monday.

&&

.UPDATE...

Gusty westerly winds have diminished this evening and humidity is
slowly rising. As such, the Red Flag Warning was allowed to
expire at 7 PM MDT. Overall, the going forecast is in fairly good
shape. However, variable mid and high level clouds moving over the
region have been trending towards "mostly cloudy" rather than
"partly cloudy", especially over eastern portions of the Great
Falls forecast area. Have gone ahead and updated sky condition to
reflect the higher cloud coverage for the remainder of Thursday
night and into Friday using the early evening guidance update. No
further updates are anticipated this evening. mpj

&&

.AVIATION...
1100 PM MDT Thu Oct 8 2020 (09/06Z TAF Period)

VFR conditions are expected throughout the duration of the 0906/1006
TAF period; however, haze from wildfires burning across the Western
US and locally (Yogo Fire - impacting the KLWT terminal) may bring
reduced visibilities at times. A weak surface front pushing south
from Southern Canada will move across the Hi-Line before stalling.
This front will bring a wind shift to more of the north for the KCTB
and KHVR terminals. Low level wind shear is also possible over the
plains of Central and North Central Montana through the overnight
hours, mainly southeast of a KHVR to KGTF line.

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

&&

.FIRE WEATHER...

Winds are forecast to decrease overnight with the passage of a
weak Canadian cold front, and they will be somewhat less breezy on
Friday with slightly cooler (about 10 degrees) and less dry
(mostly above 20 percent humidity) conditions.

A strong cold frontal passage on Saturday will likely translate
strong westerly winds aloft to the surface once again, with
another round of widespread 30 to 40 mph gusts. However,
cooling temperatures and increasing relative humidity behind the
front could alleviate some fire weather concerns. At this time, a
Fire Weather Watch has been issued for Saturday afternoon and
evening.

&&

.PREV DISCUSSION...
/ISSUED 535 PM MDT Thu Oct 8 2020/

Winds will diminish this evening as a weak cool front pushes
through the region. Am expecting variable, mainly high, clouds
overnight giving way to mostly clear skies on Friday.
Additionally, Friday afternoon's high temperatures will be less
than those of today. mpj

Saturday through Monday... This period will signal a significant
change in the weather pattern. A low pressure trough over the Gulf
of Alaska on Friday will dive south into the Pacific Northwest on
Saturday. The initial impact will be to significantly increase
southwest winds aloft once again on Saturday as another surface
trough develops to the lee of the Rockies. As a result, westerly
surface will increase once again over the area. The surface
pressure gradient in the wake of the surface trough is forecast to
be stronger than that expected today, as there will be a stronger
Canadian cold front moving in from the north. Widespread wind
gusts on Saturday could again be at least into the 30 to 40 mph
range. There has been some variation in the timing of the frontal
passage from the forecast models, with the current forecast
pushing it through the area late Saturday afternoon through
Saturday evening. The low pressure trough also seems a bit more
shallow than previously forecast. This may result in more
westerly and downsloping mid-level winds, which would keep the
initial push of precipitation limited to the mountains.
Regardless, temperatures are still forecast to drop from just
above normal on Saturday to between 5 and 10 degrees below normal
for Sunday as snow levels fall to around 5000 feet by Sunday
morning. It appears that this will be a fast-moving system,
leaving the best chance for light measurable snowfall at or above
mountain pass level. The flow aloft will shift more northwesterly
in the wake of the trough Sunday into Monday, but there will be
less moisture and continued westerly downsloping surface winds, so
again light precipitation will be limited to the mountains as
temperatures remain below normal. Coulston

Tuesday through next Thursday... Weak high pressure ridging will
bring dry weather with slightly above normal temperatures on
Tuesday, but another weak low pressure trough will cool
temperatures below normal with mainly mountain precipitation for
Wednesday into Thursday.
Coulston

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  45  74  44  74 /   0   0   0  10
CTB  41  68  45  65 /   0   0   0  30
HLN  45  75  42  74 /   0   0   0  30
BZN  35  74  34  76 /   0   0   0  10
WYS  20  67  21  64 /   0   0   0  10
DLN  36  72  37  70 /   0   0   0  30
HVR  43  71  44  77 /   0   0   0  10
LWT  45  73  43  79 /   0   0   0   0

&&

.TFX WATCHES/WARNINGS/ADVISORIES...
Red Flag Warning until 9 PM MDT this evening Gallatin National
Forest.

Fire Weather Watch from Saturday afternoon through Saturday
evening Central and Eastern Lewis and Clark National Forest
Areas...Chouteau and Fergus Counties...Helena and Townsend
Ranger Districts of the Helena National Forest...Hill and Blaine
Counties.

&&

http://www.weather.gov/greatfalls