textproduct: Bismarck

KEY MESSAGES

- Isolated thunderstorms possible far south overnight. A stronger to possibly severe storm can not be completely ruled out.

- Low chances (20 to 30 percent) for thunderstorms Wednesday night through Thursday afternoon. Isolated strong to severe storms are possible in the west Wednesday night and over much of the west and central Thursday.

- Medium chances (40 to 70 percent) chances for showers and thunderstorms Thursday night through Friday night. A few thunderstorms could be strong to severe with locally heavy rainfall. Then low chances for showers and non-severe thunderstorms through the rest of the Holiday weekend.

- Warming trend Wednesday and Thursday, with increasing humidity and temperatures in the 90s. Then a cooling trend Friday through the rest of the weekend.

UPDATE

Issued at 1003 PM CDT Tue Jul 1 2025

Activity has held south of the border over the southern end of our area, but with a modest low level jet kicking in later tonight and some high-res models indicating some possible convection developing, will keep low chances in the forecast through the overnight.

UPDATE Issued at 645 PM CDT Tue Jul 1 2025

So far convective activity over the south has remained over northwest South Dakota, but as the evening goes on a few storms still could make their way into our area, especially later on with the increasing low level jet. Around the Turtle Mountains, again the convection has held out of our area and formed just to the east, though the potential remains for a few more hours of a storm moving through there.

DISCUSSION

Issued at 131 PM CDT Tue Jul 1 2025

Currently skies were sunny across western and central ND with temperatures mainly in the lower to middle 80s. A few clouds were noted from the Turtle Mountains into eastern ND. Farther west, clouds were noted from around Miles City west to Hysham in eastern Montana, with congested cu noted on Satellite. Current winds ranged from northwest over eastern ND to southerly over the west, and light and variable in between.

The congested cu over southeast is of some concern this afternoon and early evening. The atmosphere continues to destabilize over far southwest ND. MLCape values are 500-1000 J/KG with around 35 knots of effective shear. As you go west into Montana, the dewpoints drop into the lower 50s, but currently we are seeing some mid 50s from Dickinson to Hettinger, but still capped. CAMs have been consistent today in keeping any convection just west and south of the far southwest corner of the state. It's possible we could see a cell or two sneak into the state, but think convection for the most part, should stay south.

Later tonight, we see the low level jet strengthen over South Dakota and into far southern North Dakota. It's possible we could see a stronger or possibly even a marginally severe elevated thunderstorm along our far southern counties. Hail to the size of quarters would be the main hazard. Again, it appears that South Dakota would be favored for possible severe convection, over southern ND. Will need to monitor. Overall, severe chances late this afternoon and tonight appear to be very low.

Wednesday is expected to be dry with an increasing southerly flow, bringing increasing moisture into the forecast area. Highs should climb into the 80s area wide, with some lower 90s in the far west. Upper level ridging should be maximized over western ND Wednesday afternoon into Wednesday evening. However, southwest upper flow over western and central MT will probably fire convection that could push through eastern MT and possibly into western ND later Wednesday evening. SPC has a marginal risk (level 1 of 5) for severe storms in western ND. Gusty winds to 60 mph would be the most likely hazard with these storms if they were able to make it int western ND.

Thursday and Friday we remain within a broad southwest upper flow with a warm and moist airmass remaining over the region. Low pressure develops in the northern and central High Plains Thursday and pushes east into the Plains Friday. There will certainly be ingredients for strong to possibly severe storms, as well as for heavy rainfall. However there remains a lot of uncertainty in how things will play out. Currently, SPC has a marginal risk for severe thunderstorms (level 1 of 5) over western and much of central ND on Thursday. WPC is highlighting a good portion of western and central with a marginal risk of excessive rainfall 12Z Thursday through 12Z Friday as well. The threat for severe weather on Friday should slide farther east, with mainly eastern portions of the state favored for strong to severe storms. the CSU ML page is hinting at a marginal risk for severe storms over south central into eastern ND. This will also depend on how things evolve on Thursday as well. As we head through the weekend we see a a weak upper level flow with a couple of waves moving through the area. We should see temperatures trend a bit lower, with occasional showers and thunderstorms remaining in the forecast but with a low predictability of when or where they will occur.

AVIATION /00Z TAFS THROUGH 00Z THURSDAY/

Issued at 645 PM CDT Tue Jul 1 2025

Isolated thunderstorms possible along the South Dakota border and around the Turtle Mountains this evening into the overnight hours. Otherwise, VFR conditions will prevail.

BIS WATCHES/WARNINGS/ADVISORIES

None.