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KEY MESSAGES

- Critical fire weather conditions continue this evening across western and central ND, including the James River Valley. Critical fire weather conditions expected again on Tuesday across central North Dakota, including the James River Valley.

- Strong winds expected across central North Dakota Tuesday morning through the afternoon.

- Windy conditions and low humidity values through the rest of the upcoming week may lead to daily critical fire weather conditions.

UPDATE

Issued at 730 PM CDT Mon May 11 2026

The main change with this update was to include blowing dust in the forecast through this evening in western ND based on recent satellite, ASOS/AWOS trends, and web cameras. Notable amounts of blowing dust are being transported into the area on post- frontal northwest winds. Deep mixing to between 600 and 700 mb with low-level lapse rates around 10 C/km in parts of west central and northwestern ND, in a low-level cold air advection regime, and with a 100 kt jet streak aloft atop that deeply- mixed air mass is contributing to wind gusts of 40 to 50 mph in western ND as of early this evening. Given expected gradual decreases in mixing depth and related winds between 02z and 04z, and some variation spatially and temporally in the strongest winds, we have not issued a Wind Advisory given the short duration of the event. However, the winds and continued low humidity will continue to cause critical fire weather conditions the next few hours. The primary surface cold front is just east of the Highway 83 corridor in central ND as of 00z, and is expected to continue shifting eastward. High-based thunderstorms in north central and northeastern ND have formed ahead of the front in the Rugby area, and additional high-based showers and isolated storms are occurring in the cyclonic flow of the post- frontal regime in northwest/north central ND and southern Canada as well. Given the very dry boundary layer and strong flow aloft, strong, gusty, and erratic winds are possible with this activity before it diminishes by late evening, too.

DISCUSSION

Issued at 330 PM CDT Mon May 11 2026

Warm, dry, and windy conditions are expected across western and central North Dakota throughout much of the workweek. Fire weather concerns will remain the primary forecast challenge through this period, and will be discussed at length in the Fire Weather section below.

A shortwave trough is traversing the northern Plains today, with an associated surface low moving across the southern Canadian Prairies. With the strengthening surface gradient, and with very dry conditions allowing for much of the area to become fully mixed out to 500mb, strong southerly winds from 25 to 30 MPH and gusts up to 45 MPH are expected this afternoon. Late in the afternoon, winds are expected to start veering to the northwest as a cold front extending off the aforementioned surface low moves across the region, starting in the northwest and dropping to the southeast through the evening. A brief lull in winds can be anticipated ahead of this FROPA, but will then again strengthen along and behind the cold front as CAA increases. With the best alignment of the CAA and the best pressure rises found across the area late this evening and overnight, and with the development of moderately strong, 40 to 45 knot mid level jet across central North Dakota overnight, it is expected that at least breezy northwest winds will persist overnight into Tuesday morning across central North Dakota.

Also for today, much of western and central North Dakota will fall into the warm and somewhat "moist" sector of the surface low this afternoon, promoting the seasonable warm highs in the 70s to mid 80s. With this, CAMs continue to advertise model MUCAPE values around 750 - 1000 J/KG become available ahead of the FROPA this afternoon, which could allow for the development of isolated showers or thunderstorms through the early evening. With how dry the near surface layer will remain through this period, the little rain that does reach the ground is likely to be associated with convective processes. In any case, whether or not precpitation reaches the ground or it becomes virga, gusty and erratic winds can be anticipated where it occurs. Notably, a strong to marginally severe thunderstorm is not out of the question late this afternoon and evening as a fairly well sheared environment develops across central North Dakota, with model values around 45 to 55 knots. An interrogation of model soundings during this period indicates that the most unstable parcels will be found elevated over a fairly robust capping inversion through much of this period which, along with the skinny CAPE profile advertised by the CAMs, would suggest that greatest potential hazard for any strong to marginally severe storm would be strong winds approaching 60 MPH.

Another windy, dry day is on top for western and central North Dakota on Tuesday. Considering the LLJ across eastern North Dakota, the tight pressure gradient, and the well mix boundary layer, the gusty northwest winds that persisted overnight are expected to strengthen through the morning into the early afternoon, becoming strong from 25 to 35 MPH and gusting as high as 45 MPH for most areas east of Highway 83. These strongest winds are expected to diminish through the late afternoon and evening as LLJ exits to east, and as the surface gradient continues to relax. With this in mind, we have issued a Wind Advisory for much of central North Dakota from 7 AM to 7 PM CDT. Winds to the west of Highway 83 will be somewhat lighter, but still breezy to windy with sustained speeds around 15 to 20 MPH and gusts up to 30 MPH. By the early overnight period, fairly light and variable winds are expected across western and central North, Otherwise, for Tuesday, a slightly "cooler" highs in broadly in the 70s are anticipated in the post frontal environment.

Northwesterly flow is expected to be come reestablished over the forecast area on Wednesday as an upper level ridge shifts over the Great Plains. With this, another very warm day is expected for western and central North Dakota, with highs broadly forecast in the mid 70s to lower 80s central to the lower to mid 80s west. A close low is progged to again cut across the southern Canadian Prairies early Wednesday, with lee cyclogenesis set to produce another surface low to the west of the forecast area early Wednesday morning. With the tightening of the pressure gradient ahead of this low, winds are expected to reorganize out of the south southeast and strengthen through the afternoon, allowing for speeds around 25 to 30 MPH and gusts up to around 40 MPH in the west. Mainly dry conditions are expected on Wednesday, though some isolated rain showers are possible in the evening and overnight as the attendant warm front ahead of the low system lifts across the west.

Very windy conditions are then on tap on Thursday as the aforementioned low lofts a cold front across the forecast area. With the increased CAA along and behind the front, and with model soundings indicating mixing well up into 700-750mb, it can be anticipated that winds from a strong mid level jet will find their way down to the surface. In this scenario, much of western and central North Dakota could find itself easily within Wind Advisory criteria for Thursday, if not borderline High Wind Warning criteria across portions of the northwest. The EFI for winds during this period is approaching 0.9 across the north, with a notably shift of tails along the International Border. Some uncertainty remains however, with cluster analysis revealing a minority of model members (approximately 40 percent) advertising a much more diffuse and open way aloft, resulting in a weak LLJ and thus weak winds overall. Will need to monitor this period over the next few days.

Uncertainty continues to build into the forecast Friday into the weekend regarding the potential for both winds and rain. Ensemble members are fairly split between two scenarios, one where a transient upper level ridge passing through the region, promoting drier conditions with more limited winds, while the other favors a more zonal flow pattern which would allow chances for precpitation across much of the forecast area heading into the weekend. In either scenario, there is greater agreement in a transition into a more active precpitation pattern by the late weekend into early next week a more robust long wave trough is advertised by the ensemble to move across the Great Plains.

AVIATION /00Z TAFS THROUGH 00Z WEDNESDAY/

Issued at 730 PM CDT Mon May 11 2026

VFR conditions are expected across western and central ND for most of the 00z TAF cycle. However, blowing dust in western ND will produce localized MVFR conditions through about 06z. A cold front is moving through central ND early this evening. Northwest winds behind the front are gusting to around 40 kt, but will diminish overnight with gusts to around 25 kt across most of western and central ND through the night. Winds will increase again during the day Tuesday in central ND and the James River valley with gusts to around 40 kt.

Otherwise, isolated showers and thunderstorms in northwest and north central ND this evening are expected to diminish by 06z.

FIRE WEATHER

Issued at 730 PM CDT Mon May 11 2026

Critical fire weather conditions will continue through mid to late evening with a combination of low humidity, strong winds, and a cold frontal passage continuing through central North Dakota. The Red Flag Warning remains in effect for all of western and central ND until 10 PM CDT or 9 PM MDT, though we anticipate allowing it to expire on time as winds diminish a bit overnight.

Northwest winds will somewhat diminish late this evening and overnight. Winds are expected to remain elevated across central North Dakota however, as a moderately strong mid level jet develops on the backside of the upper level low. With this, sustained speeds around 15 to 20 MPH and gusts up to 30 MPH will remain possible through Tuesday morning. Relative humidity is expected to recover to a max of around 50 to 60 percent across the west and south central, and to a max of round 60 to 70 percent across the north central.

With the lingering low level jet and strong pressure gradient lingering across eastern North Dakota Wednesday morning, northwest winds expected to again strengthen through the afternoon, again becoming sustained from 25 to 35 MPH and gusting as high as 45 MPH by the late morning and through the afternoon. Winds will be a little more tame further to the west, though still elevated from 15 to 20 MPH gusting as high as 30 MPH. Though somewhat "cooler" in the afternoon, with highs more broadly in the 70s, conditions across the forecast area will remain very dry. Minimum relative humidity is expected to again drop as low as 15 to 20 percent west of Highway 83, from 20 to 25 percent along and south of I94, and from 25 to 30 percent north of I94. The greatest overlap of strong winds and low RHs is expected across much of central North Dakota into portions of western North Dakota, where critical fire weather conditions are again expected for Tuesday. Expansion of critical fire weather conditions further west is not out of the question if the winds overperform, but confidence in such a scenario is not currently high. Winds are expected to rapidly diminish through the early evening, becoming light and variable overnight, as the low exits further into the Great Lakes region, accompanied by the low level jet and allowing the surface gradient to relax.

Critical fire weather conditions remain likely across North Dakota Wednesday through the end of the week. Minimum relative humidity is expected to drop as low as 15 to 20 percent across the west Wednesday, and across the southwest and south central on Friday, while being only as high as 20 to 30 percent elsewhere each day. Breezy to windy conditions can be expected across the west on Wednesday, while windy to very windy conditions are possible across much of North Dakota on Thursday and Friday. At least some chances for precpitation begin to build into the forecast as we head into the weekend, with widespread low to medium chances for rain late Saturday through Sunday.

BIS WATCHES/WARNINGS/ADVISORIES

Red Flag Warning until 10 PM CDT /9 PM MDT/ this evening for NDZ001>005-009>013-017>023-025-031>037-040>048-050-051. Red Flag Warning from 11 AM to 9 PM CDT Tuesday for NDZ003>005- 011>013-021>023-025-035>037-046>048-050-051. Wind Advisory from 7 AM to 7 PM CDT Tuesday for NDZ005-012-013- 022-023-025-035>037-046>048-050-051.