990
FXUS65 KTFX 100204
AFDTFX

Area Forecast Discussion
National Weather Service Great Falls MT
804 PM MDT Tue Jul 9 2024

.SYNOPSIS...
Heat and mostly dry weather persists into next week, with the
hottest days on Wednesday and Thursday. During the late week,
there are low end chances for a few isolated light showers and
thunderstorms, particularly across Southwest Montana.

&&

.UPDATE...

Only made a minor adjustment to this evening`s forecast. A few
weak thunderstorms developed over the mountains of Southwest
Montana along and south of Interstate 90 late this afternoon, and
they continue to move southeast over the area. With relative
humidities previously in the teens and currently in the 20s and
30s, little if any rain is reaching the ground; however, a few
lightning strikes did develop earlier between Big Sky and West
Yellowstone. Decreasing vertically integrated ice over the last
couple of hours has led to fewer lightning flashes and no new
lightning strikes, so am expecting any thunderstorm activity to
diminish through 10 pm. Otherwise, overnight low temperatures
should remain mild (mid 50s to lower 60s at lower elevations) with
generally light winds. -Coulston

&&

.AVIATION...
10/02Z TAF Period

VFR conditions will prevail over the CWA through the period.
However, isolated high based evening thunderstorms will occur
through about 03z between Big Sky and West Yellowstone. Do expect
surface winds to increase a bit on Wednesday afternoon.
Additionally, wildfire smoke is starting to move southward from
Canada into the CWA, along with a new wildfire east of Helena.
Thus some distant mountain ranges will be obscured by smoke
through the period. Brusda

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

&&

.FIRE WEATHER...

Building heat and dryness will accelerate the drying of fuels
over the next several days and increase fire danger indices. In
addition, overnight moisture recovery will worsen through
Thursday, particularly at mid-higher elevations. Winds are
relatively light through Wednesday with some increase in
afternoon breeziness Thursday through the weekend. This, in
addition to the risk for isolated lightning late this week into
the weekend will add to the overall increase in fire weather
concerns with continued heat and dryness likely to continue into
next week. Hoenisch

&&

.CLIMATE...

Temperatures Wednesday and Thursday are expected to reach near or
at record temperatures. The following table below shows the
forecasted temperatures with the records for that day at our
climate sites.

Record temperatures for July 10th:

Location  Forecast     Record Warm   Record Warm
            (High/Low)     High(Year)    Low(Year)
Bozeman        96/57       100 (1973)    60 (1970)
Cut Bank       95/58       101 (1973)    62 (1968)
Dillon         93/56        95 (1973)    60 (1966)
Great Falls    97/60       105 (1973)    67 (1985)
Havre          98/60       105 (1973)    68 (1968)
Helena        100/64       102 (1973)    69 (2001)
Lewistown      92/58       100 (1939)    63 (2014)

Record temperatures for July 11th:

Location  Forecast     Record Warm   Record Warm
            (High/Low)     High(Year)    Low(Year)
Bozeman        97/58        97 (2002)    59 (1973)
Cut Bank       96/60        95 (1917)    65 (1917)
Dillon         94/57        99 (2002)    57 (1953)
Great Falls    97/63        99 (2002)    70 (1957)
Havre          99/63       105 (1886)    65 (1976)
Helena        101/66       100 (2002)    69 (1985)
Lewistown      91/61        92 (1925)    64 (2013)

&&

.PREV DISCUSSION...
/ISSUED 740 PM MDT Tue Jul 9 2024/
The heat will continue to build in through mid week as the strong
upper ridge axis over the NW continues to slide east. Temperatures
this afternoon will reach into low to mid 90s across most lower
elevation locations. Wednesday and Thursday look to be the hottest
days as that upper level ridge axis build in overhead. Temperatures
will range between mid to upper 90s across lower elevations. Some
locations (especially the Helena area) may reach 100F. A shortwave
trough moving through the area on Thursday will bring a low chance
of an isolated shower/thunderstorm during the evening (<20%).
Moisture will be low however, with the 75th percentile of the NBM
showing less than 0.05" with precipitation.
-Wilson

This weekend temperatures look to be higher than average in the
mid to upper 90s as the ridge flattens and moves in from the
west. Overnight lows remain in the 60s, bringing some relief from
the hot temperatures. The rounding out of the ridge in Southwest
Montana brings the possibility of thunderstorms, although chances
of showers are low. The chance of locations receiving 0.10 of
precipitation is 10-20%. There is an increase in fire weather
concerns as the heat causes the fuels to dry out faster, and a
slight chance of drier thunderstorms during the weekend. The high
temperatures will likely remain very warm into next week.
- Kiffe/Wilson

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  60  97  63  97 /   0   0   0  10
CTB  59  95  61  95 /   0   0   0   0
HLN  64 100  66 101 /   0   0   0   0
BZN  57  96  58  97 /   0   0   0   0
WYS  44  87  46  89 /  10   0   0  10
DLN  55  93  57  93 /  10   0   0   0
HVR  60  98  63  99 /   0   0   0   0
LWT  58  92  61  91 /   0   0   0  10

&&

.TFX WATCHES/WARNINGS/ADVISORIES...
None.
&&

$$

http://www.weather.gov/greatfalls