783
FNUS75 KTFX 291745
FWSTFX

Spot Forecast for Big Sky...Gallatin County
National Weather Service Great Falls MT
1145 AM MDT Tue Jul 29 2025

Forecast is based on forecast start time of 1200 MDT on July 29.
If conditions become unrepresentative...contact the National Weather
Service.

.DISCUSSION...

There is a marginal risk for severe weather this afternoon and
evening in Big Sky which means there is a 5-10% chance of severe
weather (wind gusts > 58 mph and/or hail with a diameter of 1
inch or greater) within 25 miles of a point. There is 55% chance
for thunderstorms in Big Sky this afternoon and evening. Today the
greatest risk for thunderstorms is between 400 PM MDT and 800 PM
MDT. Tomorrow after 1200 PM MDT, there will be another round of
showers and thunderstorms.

.REST OF TODAY...

Sky/weather.........Partly sunny (55-65 percent). Showers likely
                    and chance of thunderstorms.
Chance of pcpn......60 percent.
Chance of lightning.55 percent.
Max temperature.....70-75.
Min humidity........28-33 percent.
Surface winds (mph).Northeast winds around 5 mph shifting to the
                    northwest early in the afternoon, then shifting
                    to the east late in the afternoon shifting to
                    the northwest with gusts to around 20 mph late
                    in the afternoon.
Pcpn amount.........0.04 inches.
Snowfall amount.....0.0 inches.
Visibility..........10 decreasing to 6 late in the afternoon, then
                    increasing to 10 late in the afternoon
                    decreasing to 6 late in the afternoon.

TIME (MDT)      12P 1PM 2PM 3PM 4PM 5PM
Sky (%).........48  53  57  76  67  74
Weather cov.....SCH CHC CHC LKY CHC LKY
Weather type....RW  RW  RW  RW  RW  RW
Tstm cov........SCH CHC CHC CHC CHC CHC
Chc of pcpn (%).20  30  40  60  50  60
Chc of ltng (%).20  30  40  50  60  50
Temp............72  72  72  70  69  68
RH..............36  35  34  35  35  39
Surface wnd dir.NE  N   NW  NW  E   NW
Surface wnd spd.5   5   5   10  10  5
Surface wnd gst.15  15  15  15  15  20
Visibility (sm).10  10  10  6   10  6

.TONIGHT...

Sky/weather.........Mostly cloudy (70-80 percent) then becoming
                    partly cloudy (40-50 percent) then becoming
                    mostly cloudy (45-55 percent). Chance of
                    showers and thunderstorms early in the evening,
                    then slight chance of showers and thunderstorms
                    early in the evening.
Chance of pcpn......40 percent.
Chance of lightning.27 percent.
Min temperature.....45-50.
Max humidity........95-100 percent.
Surface winds (mph).North winds around 5 mph early in the evening
                    shifting to the east, then shifting to the
                    south late in the evening shifting to the east
                    shifting to the northeast overnight becoming
                    light.
Pcpn amount.........0.01 inches.
Snowfall amount.....0.0 inches.
Visibility..........10.

TIME (MDT)      6PM 7PM 8PM 9PM 10P 11P MID 1AM 2AM 3AM 4AM 5AM
Sky (%).........74  78  80  66  38  41  41  42  48  44  50  51
Weather cov.....CHC CHC SCH SCH SCH SCH
Weather type....RW  RW  RW  RW  RW  RW
Tstm cov........CHC CHC SCH SCH SCH SCH
Chc of pcpn (%).40  30  20  20  20  20  10  0   0   0   0   0
Chc of ltng (%).30  30  30  30  30  30  0   0   0   0   0   0
Temp............63  63  62  59  57  55  54  53  52  51  49  48
RH..............48  52  55  67  73  77  78  82  86  89  90  96
Surface wnd dir.NW  N   N   N   E   S   E   NE  NE  N   N   N
Surface wnd spd.5   5   5   5   5   5   5   5   5   0   0   0
Surface wnd gst.15  15  15  15  15  10  10  10      5   5   5
Visibility (sm).10  10  10  10  10  10  10  10  10  10  10  10

.WEDNESDAY...

Sky/weather.........Mostly sunny (45-55 percent). Chance of showers
                    and thunderstorms in the afternoon.
Chance of pcpn......50 percent.
Chance of lightning.42 percent.
Max temperature.....68-73.
Min humidity........35-40 percent.
Surface winds (mph).Light winds becoming northeast around 5 mph
                    early in the afternoon, then shifting to the
                    north late in the afternoon.
Pcpn amount.........0.06 inches.
Snowfall amount.....0.0 inches.
Visibility..........10.

TIME (MDT)      6AM 7AM 8AM 9AM 10A 11A 12P 1PM 2PM 3PM 4PM 5PM
Sky (%).........53  56  40  33  38  34  65  65  65  65  65  65
Weather cov.....                        CHC CHC CHC CHC CHC CHC
Weather type....                        RW  RW  RW  RW  RW  RW
Tstm cov........                        CHC CHC CHC CHC CHC CHC
Chc of pcpn (%).0   0   0   0   0   0   50  50  50  50  50  50
Chc of ltng (%).0   0   0   0   0   0   40  40  40  40  40  40
Temp............48  47  49  52  58  64  67  68  70  70  69  68
RH..............100 99  96  90  71  57  49  45  40  40  40  42
Surface wnd dir.NE  E   SE  E   E   E   E   NE  N   N   N   N
Surface wnd spd.0   0   0   0   0   0   5   5   5   5   5   5
Surface wnd gst.5   5   5   5   10  10  10  15  15  15  15  15
Visibility (sm).10  10  10  10  10  10  10  10  10  10  10  10

$$
Forecaster...Gesell
Requested by...Kevin Larsen
Type of request...OTHER
.TAG 2518584.4/TFX
.DELDT 07/29/25
.FormatterVersion 2.0.0
.EMAIL kevin@readygallatin.com,matt.boxmeyer@gallatin.mt.gov, tfx.ops@noaa.gov