


Area Forecast Discussion
Issued by NWS Bismarck, ND
Issued by NWS Bismarck, ND
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019 FXUS63 KBIS 081951 AFDBIS Area Forecast Discussion National Weather Service Bismarck ND 251 PM CDT Tue Jul 8 2025 .KEY MESSAGES... - Widespread high temperatures in the 90s are expected on Wedneday. - Isolated to scattered severe thunderstorms are possible late Wednesday afternoon and evening. Isolated severe thunderstorms are then possible late Thursday afternoon and evening. - Temperatures cool down for the end of the workweek, before warming back up through the weekend. && .DISCUSSION... Issued at 250 PM CDT Tue Jul 8 2025 Near northwesterly flow over the northern Plains this afternoon is expected to turn increasingly zonal through the evening as a mid to upper level ridge slides in from the west. Generally clear and calm conditions are expected across the forecast area through the remainder of the day today as high pressure continues to move in from the southern Canadian Prairies. With this, highs today are broadly forecast from the mid 70s in north central North Dakota up to the upper 80s in the far southwest. Later this evening and tonight, a weak shortwave topping over the ridge and the redevelopment of a LLJ overnight will allow for a increase in precipitation chances in the far southwest. Overall chances for showers are low (10 to 15 percent), but you could get few isolated rumbles of thunder. Otherwise, low temperatures overnight are forecast from the mid 50s east to the mid 60s west. With prevailing clear skies and the better penetration of the thermal axis associated with the upper level ridge on Wednesday, high temperatures are expected to fall broadly into the 90s across western and central North Dakota. It would not take much to tip portions of far western North Dakota into the lower 100s. Regarding the potential for heat headlines tomorrow, conditions across the west, where highs are forecast in the upper 90s, are expected to be dry, with dewpoints peaking only into the 40s and 50s. In central North Dakota, where higher dewpoints in the mid to upper 60s are anticipated, surface temperatures are "only" forecast in the lower to mid 90s. Thus, apparent temperatures across western and central North Dakota are expected to remain below 100 F at the time of this forecast, mainly in the lower to mid 90s. That being said, somewhat weak winds west of Highway 83 will make conditions feel very muggy. Now onto the severe weather potential Wednesday. Dewpoints across central North Dakota are expected to rise in mid to upper 60s by late tomorrow afternoon. With ample near surface moisture, an explosively unstable environment with model MUCAPE values exceeding 3000 to 4000+ J/KG, high low to mid level lapse rates exceeding 8 C/km, sfc temperatures approaching convective temps, and a weak surface trough / warm front progressing eastward through the afternoon and evening, CI is anticipated by the late afternoon, early evening. What remains in question is the quality of the sheared environment. CAMs are reticent to advertise much more than 30 to 35 knots of 0-6 KM of bulk shear ahead of the boundary, which may keep any supercellular storms that do develop fairly transient in nature. Thus, despite the high CAPE values, we have opted to keep the potential hail size up to around golf balls. Of note is the high DCAPE values advertised by CAMs at this time, with a distinct inverted V sounding evident on BUFKIT. With this, strong wind gusts up to 70 MPH are also expected. Otherwise, there may also be an isolated tornado threat initially in the late afternoon, early evening period, driven less by near surface SRH as opposed to to the exceedingly unstable environment taping into vorticity along the wind shift. At it stands, SPC has place portions of south central North Dakota into a Slight (level 2 of 5) Risk for scattered severe storms tomorrow afternoon, with a Marginal (level 1 of 5) Risk for isolated severe storms essentially everywhere else. High PWATs around 1.6 inches are also advertised which could promote periods of heavy rainfall in some localized areas, though storms are anticipated to be moving fairly quickly. Storms are expected to move across the James River and into eastern North Dakota by the late evening, early overnight period. On to Thursday. Like Wednesday, and explosively unstable informant with MUCAPE values well above 4000+ J/KG cape is modeled over central North Dakota. Dewpoint values Thursday afternoon are also expected to peak into the upper 60s to lower 70s by the late afternoon, early evening period, highest across the southern James River Valley. Along with high lapse rates exceeding 8-9 C/KM in the low to mid layers, CI is possible ahead of a cold front passing from northwest to southwest in the early evening. However, marginal bulk shear continues to plague these potential storms. Current model trends keeps shear relatively low, sub 30 knots, through much of the afternoon and evening, though shear then increases on the backside of the cold front. Additionally, a moderately strong cap across much of central North Dakota may help keep CI just on the eastern edge of the forecast area through the late afternoon and evening, meaning that any thunderstorms that do develop would quickly exit into eastern North Dakota. With that in mind, we are continue to advertise hail up to the size of ping-pong balls and wind gusts up to 60 MPH. As of the current forecast cycle, SPC places essentially all of western and central North Dakota in a Marginal (level 1 of 5) Risk for isolated severe thunderstorms on Thursday. Additionally, high PWATs exceeding 1.7" plus across central North Dakota again hint at potentially high rainfall rates with any thunderstorm that does develop, though storms are not anticipated to remained park over any given location for long. Otherwise, for Thursday, high temperatures broadly in the 80s and lower 90s are anticipated. On the backside of the cold front, cooler highs mainly in the 70s are forecast for Friday. With an upper level trough closing off over the northern Plains, chance for showers and a few thunderstorms will linger through the morning and early afternoon on Friday (20 to 40 percent chances, highest across the west). Aloft, the return of northwesterly flow ahead of building upper level is anticipated to promote another warming trend that brings the forecast area back into the 80 and lower 90s this weekend into early next week. With this northwesterly flow, near daily chances for showers and afternoon thunderstorms will continue through much of this period. && .AVIATION /18Z TAFS THROUGH 18Z WEDNESDAY/... Issued at 250 PM CDT Tue Jul 8 2025 VFR ceilings and visibility are anticipated at all terminals throughout the 18Z TAF period. Tonight through tomorrow morning, LLWS is expected at KXWA from 06z to 10Z. Winds will generally organize out of the southeast overnight, becoming breezy with speeds up to 15 knots and gusts up to 25 knots in the northwest. Winds then turn southerly through the morning, the gusty winds move over central North Dakota. && .BIS WATCHES/WARNINGS/ADVISORIES... None. && $$ DISCUSSION...Adam AVIATION...Adam