Marine Weather and Tide Forecast for South Hills, MT

UPDATE
/Issued 1017 AM MDT Wed Jun 18 2025/

Morning update has been published, with the primary change being the addition of a Winter Storm Watch for the East Glacier Park Region from Saturday afternoon through Sunday afternoon. Otherwise the near-term forecast remain on track, with minimal changes made.
- Moldan

DISCUSSION
/Issued 1017 AM MDT Wed Jun 18 2025/

- Meteorological Overview: A shortwave upper level ridge will build over the CWA today, resulting in quiet but warm conditions.

On Thursday...the flow aloft becomes more southwest by the afternoon, as upper level disturbances approach the CWA from the Southwest. This will lead to scattered showers/thunderstorms developing over Southwest and eventually Central MT by the late afternoon hours. There will be enough instability for an isolated severe storm.

For Friday...expect the southwest flow aloft to continue as the main upper level low approaches from the west. There is the potential for severe storms on Friday across the entire CWA
However, cloud cover and morning precipitation could lower the threat for severe storms over the western portions of North Central MT a bit. Additionally, a cooling trend will begin on Friday, with afternoon temperatures not quite as warm. The moisture in the airmass will also increase to over one inch. This will allow for the potential for some storms to produce heavy rainfall, with the areas along the Highway 2 corridor from Browning to Havre the most favored area at this time for heavy rainfall.

For Saturday and Sunday...it will be officially summer by this time, so a summer storm that is likely to produce winter conditions is expected to affect the CWA during this period. Snow levels will lower Saturday and Saturday night across the CWA, with Sunday morning likely being the coldest period. Snow levels could lower to around 5000 feet over the northern portions of the CWA
Snowfall amounts could be impactful along the Rocky Mountain Front, especially in Glacier Park. Overall, temperatures will be well below normal across the entire CWA during this period.

For Monday through Wednesday, expect a nice warming trend with the chances for precipitation becoming more isolated during this period.

- Forecast Confidence & Scenarios:

Low humidity, warm temperatures and breezy winds will create some areas of elevated fire weather conditions today and Thursday.
However, conditions do not look widespread or last long enough for a fire weather highlight at this time.

Some storms could produce strong wind gusts or large hail Thursday and Friday. However, some of the higher resolution models are not showing the wind gusts quite as strong as earlier thought.
Additionally, cloud cover on Friday could limit the area that could be impacted by any severe storms.

Additionally, with precipitable water on the high side Friday, some storms could produce heavy rainfall, or possible flash flood conditions. Thus portions of the hi-line are in a marginal risk at this time.

Snowfall for Saturday and Sunday is looking impactful in Glacier Park. There is a 60 percent chance snowfall could exceed 6 inches of snow for elevations above 6000 feet. Winter statements for this event are looking more likely, and could be issued as early as later today.

AVIATION
18/18Z TAF Period

VFR conditions will prevail across all terminals during this TAF period with scattered to few high-level clouds around. At all but the KBZN terminal there will be gusty winds around during at least a portion of this TAF period. Across North-central Montana during the beginning of this TAF period there will isolated instances of low-level wind shear and mountain wave turbulence.

The one exception to VFR conditions will be for areas near Helena because of the Jericho wildfire, which is about 10 miles due west of the Helena airport. This wildfire could produce columns of smoke at times that could impact the Helena airport on short notice. IG/Brusda

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

PRELIMINARY POINT TEMPS/POPS
GTF 84 50 85 54 / 0 0 10 60 CTB 81 49 79 50 / 0 0 0 30 HLN 86 52 85 55 / 0 0 20 50 BZN 85 47 88 52 / 0 0 20 40 WYS 74 37 82 42 / 0 0 10 30 DLN 82 45 86 50 / 0 0 20 30 HVR 85 54 85 55 / 0 0 0 40 LWT 77 49 80 52 / 0 0 10 70

TFX WATCHES/WARNINGS/ADVISORIES
Winter Storm Watch from Saturday afternoon through Sunday morning for East Glacier Park Region.