Area Forecast Discussion
Issued by NWS Billings, MT
Issued by NWS Billings, MT
432 FXUS65 KBYZ 301920 AFDBYZ Area Forecast Discussion National Weather Service Billings MT 120 PM MDT Mon Jun 30 2025 .KEY MESSAGES... - Turning quite warm this week with many locations in the 90s Tuesday through Thursday. - Dry conditions today, then chance of thunderstorms gradually increases through the middle of the week. && .DISCUSSION... Today through Tuesday night... Currently, ridging is allowing for warmer and dryer air to dominate. Highs today are expected to be in the 80s. For Tuesday, weak energy in the low levels and monsoonal moisture beginning to advect in from the southwest will allow for afternoon scattered showers and thunderstorms mainly for the mountains and foothills. With the expectation of these showers and thunderstorms being high based, the main concern will be gusty winds. There is also a small chance (10-20%) for showers and thunderstorms late Tuesday afternoon for southeast MT, although there is some uncertainty amongst hi-res models on where or if these will form. There is decent forcing with a weak 500 mb jet overhead, along with 30-40 kts of shear and near 1000 J/kg of MUCAPE for southeast MT. With that, if any thunderstorms do form, they will be strong with gusty winds associated with them. Highs Tuesday will be in the upper 80s to mid 90s. TS Wednesday through Sunday... Ridge will be over the area Wednesday helping to boost temperatures into the mid to upper 90s, and can`t rule out some triple digits from Billings east toward Miles City. Despite the ridge being in place there will be mid level moisture advection from the southwest (Monsoon), and low level moisture advection from the southeast due to the thermal induced surface trof to the west of the area resulting in southeasterly low level winds. So, its going to get hot and muggy (PWATs ~1.0 inches) with 20 to 40 percent chances for afternoon/evening showers and thunderstorms across the forecast area Wednesday. Ridge axis gets pushed eastward a bit on Thursday allowing heights aloft to drop some. This combined with more afternoon/evening cloud cover with late day convection will drop temperatures 5 to 8 degrees from Wednesdays highs, a bit cooler than previous forecasts hinted at. With continued influx of low to mid level moisture, and with a lack of persistent low level winds to move/dry out the previous days precipitation, the atmosphere will continue to moisten up (PWATs 1-1.5inches) resulting in higher precipitation chances (40 to 60 percent) along with heavier precipitation amounts where showers and thunderstorms do develop. A more substantial Pacific trof moves in from the northwest on Friday knocking temperatures back into the low to mid 80s, near seasonal levels in many areas. The cold front and cooler mid level air will increase instability and lift over the area keeping a good chance (30-60 percent)for showers and thunderstorms going, but the northerly low level flow will lower PWATs compared to Thursdays values reducing the heavier precipitation potential. Seasonal temperatures and continue afternoon and evening shower and thunderstorm chances continue through the weekend. Regarding the mid week heat: While temperatures will be well into the 90s with even a few triple digits, the forecast temperatures are not unusual for this time of year, which is generally the warmest time of year for the northern Rockies. The latest Extreme Forecast Index is not showing high temperatures over the 60th percentile for our area Wednesday which will be the warmest day of the forecast period. Lows will get into the 60-70th percentile, but still not extreme (mid 60s to low 70s F). That said the combination of heat and humidity is starting to register on the HeatRisk forecast for Wednesday and to a lesser extent Thursday. If trends continue may need some heat advisory products for areas east of Billings Wednesday. Those with outdoor activities (recreation or work) should be thinking about heat safety precautions as the warmest temperatures (and heat indices) of the season arrive this week. Chambers && .AVIATION... VFR conditions will prevail through the period. Expect scattered showers and thunderstorms to develop mainly over the mountains and foothills (KLVM, KSHR) Tuesday afternoon. Isolated showers and thunderstorms are also possible (10-20% chance) for southeast MT (KBHK) late Tuesday afternoon. TS && .PRELIMINARY POINT TEMP/POPS... Tue Wed Thu Fri Sat Sun Mon ----------------------------------------------------------- BIL 057/093 062/095 063/090 062/082 059/082 057/086 059/089 00/U 11/B 22/T 44/T 44/T 32/T 21/U LVM 052/093 055/090 056/085 053/080 050/079 050/084 052/086 01/U 23/T 34/T 55/T 54/T 32/T 22/W HDN 056/095 060/098 063/091 062/083 058/083 055/087 058/091 00/U 11/B 32/T 44/T 44/T 31/U 21/U MLS 057/096 063/099 068/096 066/087 060/083 058/086 060/090 00/U 10/U 31/B 43/T 43/T 31/U 21/U 4BQ 057/093 062/096 068/093 065/083 060/081 058/084 060/089 00/U 10/U 31/B 53/T 33/T 31/U 21/U BHK 053/091 060/093 065/094 062/084 057/080 055/083 057/085 00/U 10/U 31/B 43/T 33/T 32/T 21/U SHR 053/092 057/094 060/088 057/079 052/080 051/084 054/087 01/U 11/B 23/T 55/T 44/T 32/T 21/U && .BYZ WATCHES/WARNINGS/ADVISORIES... MT...None. WY...None. && $$ weather.gov/billings