textproduct: Bismarck

KEY MESSAGES

- Dangerous heat continues across southern North Dakota today, with afternoon temperatures and heat index values as high as 105 degrees.

- Temperatures remain hot across southern North Dakota through Thursday. A slow but steady cooling trend is then favored this weekend into next week.

- Scattered thunderstorms could develop across northern North Dakota tonight. Severe weather is not expected, but a few stronger storms could produce small hail, gusty winds, and heavy rain.

UPDATE

Issued at 942 AM CDT Tue Jul 14 2026

Little updates needed this morning. Some low clouds and perhaps patchy fog continues to linger in west central portions. Overall this will either dissipate or push westward through the morning, although made some sky and patchy fog adjustments through this morning to account for this lingering low level moisture. Otherwise the forecast remains on track.

UPDATE Issued at 652 AM CDT Tue Jul 14 2026

An area of low clouds and fog is migrating westward into western North Dakota early this morning. Think this should scatter/lift quickly by mid morning. No significant changes are needed with this update. Current conditions and trends were blended into the forecast.

DISCUSSION

Issued at 444 AM CDT Tue Jul 14 2026

A very strong upper level ridge persists over the central CONUS early this morning, with high pressure over southern Minnesota and central Wisconsin pushing 500 mb heights to near 600 dam. Ensemble guidance shows high confidence in the upper ridge persisting through at least Thursday, although mid/upper level heights are forecast to gradually lower over time. A stationary surface boundary remains parked from northeast to southwest North Dakota early this morning. This boundary is forecast to reorient itself in a west-to-east fashion this afternoon, cutting through the state somewhere between Highway 200 and Interstate 94. A corridor of locally higher dewpoints in the upper 60s to lower 70s resides along the northwest side of the boundary where some patchy fog has developed, and HRRR/RAP guidance shows this plume of enhanced moisture continuing to hug the poleward side of the boundary through its latitudinal reorientation this afternoon. A surface high pressure sagging southeastward into the Canadian prairie provinces today will direct slightly cooler air into northern North Dakota, where the Extreme Heat Warning has expired. But it will still be seasonably warm to hot across the north today with highs in the mid 80s to lower 90s. Much of southern North Dakota is on track to see another day of high temperatures around 100 to 105. Areas north of I-94 are unlikely to reach a temperature of 100 today, but the aforementioned higher dewpoints combined with afternoon temperatures still well into the 90s could force heat indices into the 100 to 105 range as far north as the Highway 200 corridor. Supplemental heat forecasting tools, such as the maximum wet-bulb globe temperature (WBGT) risk, continue to show categorical values in the high to extreme range for what will be the 4th consecutive day.

An area of mid level frontogenesis is forecast to strengthen along the Canadian border tonight as low amplitude shortwave energy rounds the top of the ridge. A majority of CAMs initiate a west-to-east band of scattered thunderstorms in response to this increased synoptic scale forcing by around midnight, with a north-to-south ensemble spread from around Highway 2 to the Canadian border. Any storms that develop tonight should remain elevated, but could have access to 1000-2000 J/kg MUCAPE. Effective bulk shear does not appear to exceed 30 kts, but model soundings show some uncertainty in the height of the inflow layer. If parcels are able to be forced above the elevated LFC, there may be enough shear for a few storms to become strong. Think the main threat would be hail, but an onion- shaped lower thermal profile in model soundings indicates some potential for gusty winds as well. There is also a very low but non- zero risk for clusters of thunderstorms remaining nearly-stationary for a few hours and producing excessive rainfall over a small geographic area. Showers may linger across the far north into Wednesday morning, but thunderstorm probabilities greatly diminish after sunrise.

The Wednesday high temperature forecast takes another small step in the cooler direction, ranging from around 80 in the Turtle Mountains area to still around 100 in southwest North Dakota where drier air should keep maximum heat indices at or lower than the air temperature at any given time. On Thursday, the hottest afternoon temperatures of near 100 shift from southwest to south central North Dakota, with 80s across the far north and 90s elsewhere. Maximum forecast heat indices on Thursday are still around 100 or lower, but the maximum WBGT risk shows a greater areal coverage of both the High and Extreme categories on Thursday compared to Wednesday. There could be another round of scattered showers and thunderstorms across far northern parts of the state Wednesday evening into Thursday morning, but these would be more likely to move in from the west rather than develop overhead, and forecast CAPE is much weaker over this time period.

Ensemble support for broad ridging over the central CONUS continues into the weekend, but there are signs its amplitude and intensity could gradually wane, leading to increased probabilities for shortwaves being allowed to pass through the region. Then early next week, ensemble clusters are honing in on a transition to a northwest flow pattern over the Northern Plains as strong ridging shifts back westward over the Rockies. The NBM does indicate a gradual but persistent cooling trend through the middle of next week, with both high and low temperatures falling closer to late-July normal values.

AVIATION /12Z TAFS THROUGH 12Z WEDNESDAY/

Issued at 652 AM CDT Tue Jul 14 2026

An area of low clouds/fog with IFR/LIFR ceilings and patchy visibility reductions is migrating westward from central into western North Dakota early this morning. KDIK and KXWA could briefly be impacted, but the low clouds and fog are forecast to diminish through the morning. VFR conditions are otherwise expected to prevail. Scattered thunderstorms are likely to develop across northern North Dakota tonight. KXWA and KMOT could be near the southern edge of the storms, but confidence is not high enough to include a PROB30 mention with this set of TAFs. Winds will become easterly around 15-20 kts across northern North Dakota this afternoon, with gusts to around 25-30 kts. Southern North Dakota will see lighter east-southeast winds around 10-15 kts during the afternoon. Breezy conditions could persist through tonight.

BIS WATCHES/WARNINGS/ADVISORIES

Extreme Heat Warning until 10 PM CDT /9 PM MDT/ this evening for NDZ017>020-022-023-025-031>033-035>037-040>044-046>048-050- 051-057>062.