193
FXUS63 KBIS 030001
AFDBIS
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BISMARCK ND
701 PM CDT TUE JUN 2 2026
KEY MESSAGES
- ISOLATED TO SCATTERED SEVERE THUNDERSTORMS EXPECTED OVER MUCH
OF WESTERN AND CENTRAL NORTH DAKOTA THROUGH THIS EVENING.
- ISOLATED TO SCATTERED SEVERE THUNDERSTORMS POSSIBLE OVER
CENTRAL INTO EASTERN NORTH DAKOTA ON WEDNESDAY.
- LOW TO MEDIUM CHANCES OF SHOWERS AND THUNDERSTORMS THURSDAY
THROUGH THE REMAINDER OF THE WEEK.
- HIGHS IN THE 70S AND 80S THROUGH THE WORKWEEK, WARMING INTO
THE 80S AND LOWER 90S FOR THE WEEKEND.
UPDATE
ISSUED AT 700 PM CDT TUE JUN 2 2026
** MESOSCALE DISCUSSION **
THUNDERSTORMS HAVE FORMED ALONG THE PRE-FRONTAL WIND SHIFT/
DIFFERENTIAL MIXING BOUNDARY FROM NEAR FESSENDEN SOUTHWARD
TO THE PETTIBONE, TAPPEN, NAPOLEON, WISHEK, AND ASHLEY AREAS.
IN THIS AREA, CAPPING HAS BEEN ERODED IN THE ABSENCE OF THE HIGH
CLOUDS THAT HAVE RESULTED IN MORE MLCIN FURTHER WEST. THERE IS
LARGE BOUYANCY WITH MLCAPE AROUND 2000 J/KG, BUT EFFECTIVE SHEAR
IS GENERALLY LESS THAN 30 KT, AND THOSE VECTORS ARE ORIENTED
PARALLEL TO THE WIND SHIFT. THIS MEANS THAT WE HAVE SEEN AND
WILL CONTINUE TO EXPECT MULTICELL, PULSE-TYPE STORMS ALONG THIS
AXIS, WITH A MARGINAL RISK OF HAIL TO AROUND HALF DOLLAR SIZE
AND DAMAGING WIND GUSTS UP TO 60 MPH. NOTE THAT GIVEN THE WEAK
SHEAR ENVIRONMENT, HAIL DIAGNOSTIC TOOLS SUCH AS MRMS AND
SINGLE-RADAR MESH WILL TEND TO OVERESTIMATE HAIL SIZES WITH
THESE STORMS.
FURTHER WEST, STORMS ALONG/AHEAD OF THE COLD FRONT, E.G., IN
SIOUX COUNTY, HAVE STRUGGLED TO BECOME ESTABLISHED IN THE FACE
OF LARGER MLCIN. SIMILARLY, POST-FRONTAL CONVECTION, SUCH AS
THAT NEAR GLEN ULLIN AND CENTER AS OF 00 UTC, HAS ALSO BEEN
STRUGGLING TO INTENSIFY. THESE AREAS OF CONVECTION REPRESENT
ONLY A LOW RISK OF INTENSIFICATION AND SEVERE-STORM RISK FOR
THE REMAINDER OF THE EVENING. AS OBSERVATIONAL TRENDS ALLOW,
WE WILL CANCEL WESTERN AND NORTHERN PORTIONS OF THE SEVERE
THUNDERSTORM WATCH EARLY IN COLLABORATION WITH SPC.
CJS
UPDATE
ISSUED AT 410 PM CDT TUE JUN 2 2026
** MESOSCALE DISCUSSION **
A SEVERE HAIL AND WIND RISK WILL CONTINUE ACROSS CENTRAL ND THE
NEXT SEVERAL HOURS, WITH ONLY A LOW TORNADO RISK. IN THIS
SCENARIO, THE MAIN HAZARDS WILL BE FROM LARGE HAIL AND DAMAGING
WINDS, WHICH IS WHY A SEVERE THUNDERSTORM WATCH HAS BEEN ISSUED.
TECHNICAL DISCUSSION: AS OF 21Z, THUNDERSTORMS INCLUDING SOME
PREVIOUS MARGINAL SUPERCELL STRUCTURES ARE FOCUSED IN THE
MCHENRY, PIERCE, AND SHERIDAN COUNTY AREAS. THIS IS ALONG A PRE-
FRONTAL TROUGH, AND POSSIBLY WHERE THE COLD FRONTAL ZONE HAS
BEGUN TO MERGE WITH THAT TROUGH, RESULTING IN ADDITIONAL LOW-
LEVEL CONVERGENCE. MLCAPE ON THE ORDER OF 2000 J/KG AND
EFFECTIVE-LAYER SHEAR ON THE ORDER OF 35-40 KT IN THAT ZONE
FAVOR THE MARGINAL SUPERCELL STRUCTURES WITH AN ATTENDANT LARGE
HAIL AND DAMAGING WIND RISK. HOWEVER, ANVIL-LEVEL FLOW DOES
WEAKEN WITH NORTHWARD EXTENT, AND THE ORIENTATION OF DEEP-LAYER
SHEAR VECTORS TO THE SURFACE BOUNDARIES SUGGESTS GRADUAL UPSCALE
GROWTH WILL OCCUR IN THIS AREA IF OR WHEN ADDITIONAL INITIATION
OCCURS.
FURTHER SOUTHWEST, THE PREFRONTAL SURFACE TROUGH IS SEEN ON
RADAR FINE-LINE FROM NEAR MERCER TO PRICE, CROWN BUTTE LAKE,
AND CARSON. THE 18Z KBIS RAOB SAMPLED RESIDUAL CAPPING WITH
MLCIN AROUND -50 J/KG. AS SURFACE TEMPERATURES REACH THE MID
80S F, THAT CAPPING BECOMES MINIMIZED, BUT HIGH-LEVEL CLOUDS
SPREADING ACROSS GRANT, MORTON, AND INTO BURLEIGH COUNTIES
CASTS SOME DOUBT ON THE TIMING OF CONVECTIVE INITIATION. WE
BELIEVE THAT EVENTUALLY ADDITIONAL DEVELOPMENT WILL OCCUR
IN SOUTH CENTRAL ND, BUT ROBUST DEVELOPMENT MAY TAKE SOME
TIME AND ADDITIONAL FRONTAL LIFT TO OVERCOME THE RESIDUAL
CAPPING LAYER. THE HIGHEST PROBABILITY OF DEVELOPMENT MAY
INITIALLY BE OVER SIOUX AND SOUTHERN GRANT COUNTIES, WHERE
SATELLITE TRENDS SUGGEST MORE ROBUST UPSTREAM DEVELOPMENT
OCCURRING IN AN AREA WHERE DOWNSTREAM HIGH-CLOUD SHADING IS
LESS PREVALENT.
THERE IS ALSO A LOW TO MEDIUM PROBABILITY THAT THE LINE OF
CUMULUS FROM KIDDER SOUTH INTO EMMONS COUNTIES, ON THE EDGE OF
RICHER LOW-LEVEL MOISTURE REPRESENTING A DIFFERENTIAL HEATING
BOUNDARY, COULD RESULT IN PRE-FRONTAL INITIATION. HOWEVER, DEEP-
LAYER SHEAR IS WEAKER THERE AND WOULD RESULT IN MORE MARGINAL,
MULTICELLULAR TYPE OF STORMS.
GENERALLY-SPEAKING, LOW-LEVEL HODOGRAPHS ARE RELATIVELY SMALL,
AND ACCORDINGLY, LOW-LEVEL SRH AHEAD OF THE FRONT IN THE BUOYANT
SECTOR IS 100 M2/S2 OR LESS. DEEP-LAYER SHEAR VECTORS ARE ALSO
ORIENTED PARALLEL TO THE FRONT, FAVORING UPSCALE-GROWING AND
MESSY MODES. THIS ALL SUGGESTS THAT THE TORNADO RISK IS LOW
OVERALL.
CJS
DISCUSSION
ISSUED AT 151 PM CDT TUE JUN 2 2026
RELATIVELY WELL STACKED LOW PRESSURE IS PRESENT OVER SOUTHERN
SASKATCHEWAN. THIS LOW WILL VERY GRADUALLY SLIDE EASTWARD OVER THE
NEXT COUPLE DAYS. DURING THIS TIMEFRAME, AN ASSOCIATED VERY
SLOW MOVING COLD FRONTAL BOUNDARY CURRENTLY DRAPED NORTH TO
SOUTH OVER WESTERN NORTH DAKOTA WILL SLIDE EASTWARD. THIS
FRONTAL BOUNDARY WILL LIKELY BECOME QUASISTATIONARY, AND
POSSIBLY RETROGRADE, AT TIMES. SHOWERS AND THUNDERSTORMS ARE
PRESENT AND WILL CONTINUE TO FREQUENTLY DEVELOP ALONG AND AHEAD
OF THIS FRONTAL BOUNDARY.
HIGH PRESSURE OVER THE GREAT LAKES REGION WILL CONTINUE ADVECTING
MOISTURE FROM THE GULF OF AMERICA INTO THE NORTHERN PLAINS. THIS
ADDED MOISTURE, WITH BOUNDARY LAYER DEWPOINTS IN THE MID 50S TO LOW
60S WILL HELP PRODUCE A BUOYANT ATMOSPHERE. IN ADDITION, DEEP
LAYER SHEAR ALONG AND AHEAD OF THE FRONT IS GENERALLY PROGGED AT
AROUND 35 TO 45 KTS WITH A SOUTHWESTERLY COMPONENT. COMBINED,
THIS SHOULD PRODUCE THE CONDITIONS FOR ISOLATED TO SCATTERED
SEVERE THUNDERSTORMS THIS AFTERNOON AND EVENING. WITH THE
SOUTHWESTERLY COMPONENT OF THE 0 TO 6 KM BULK SHEAR VECTORS AND
A NORTH TO SOUTH FRONTAL BOUNDARY, SUSPECT CLUSTERS ARE THE MOST
LIKELY THUNDERSTORM MODE ALONG MOST OF THE FRONT. CONSIDERING
THERE IS ALREADY A CLUSTERISH LINE OF SHOWERS AND THUNDERSTORMS
ALONG THE FRONTAL BOUNDARY, SUSPECT A LIMITED TIMEFRAME FOR ANY
DISCRETE CELLS TO DEVELOP THIS AFTERNOON. THOUGH ONE HAS
ALREADY DEVELOPED NEAR THE TURTLE MOUNTAINS AS OF THIS WRITING.
THIS MEANS THAT WHILE THERE MAY BE A WINDOW FOR GOLF BALL SIZE
HAIL AND AN ISOLATED TORNADO THREAT, THIS MAY WIND UP BEING A
CASE WHERE WIDESPREAD MARGINAL SEVERE THUNDERSTORMS PREVAIL
OVERALL. IN ADDITION, SLOW MOVING STORM MOTIONS WITH THE
POTENTIAL FOR TRAINING COULD LEAD TO HEAVY RAIN AND A LOCALIZED
FLOODING EVENT.
OF NOTE, A MESOANALYST WILL PRODUCE A MESOANALYSIS DISCUSSION
WITHIN THE NEXT HOUR OR TWO. THIS WILL PROVIDE EVEN FURTHER
DETAILS IN REGARD TO THE SEVERE WEATHER THREAT BASED ON THE
EVOLVING SEVERE WEATHER ENVIRONMENT. DEPENDING ON HOW THE
ENVIRONMENT EVOLVES, CHANGES TO THE ABOVE THREAT EXPECTATIONS
ARE NOT OUT OF THE QUESTION.
WHILE THERE MAY BE INITIAL LLJ DEVELOPMENT THIS EVENING MAINLY
OVER THE EASTERN HALF OF THE STATE, IT DOES NOT LOOK TO PERSIST
THROUGH THE NIGHT. THEREFORE, WHILE ISOLATED TO SCATTERED
SHOWERS AND THUNDERSTORMS ARE LIKELY TO PERSIST THROUGH AT LEAST
PARTS OF THE AREA THROUGH TONIGHT, THE SEVERE THREAT WILL
LIKELY WANE RAPIDLY AS THE SUN SETS, INSTABILITY DECREASES, AND
CAPPING INCREASES. STILL, A FEW STRONG STORMS ARE NOT ENTIRELY
OUT OF THE QUESTION OVERNIGHT.
FOR WEDNESDAY, THE AFOREMENTIONED FRONTAL BOUNDARY WILL CONTINUE TO
GRADUALLY SHIFT EASTWARD AND AS SUCH, SO WILL THE SEVERE THREAT.
THEREFORE, CONCUR WITH SPC THAT THE HIGHEST SEVERE POTENTIAL FOR
WEDNESDAY WILL BE IN THE SOUTH CENTRAL (MAINLY EAST OF HWY 83)
AND IN EASTERN NORTH DAKOTA. THE BIGGEST THREATS WILL REMAIN
STRONG WINDS AND LARGE HAIL, THOUGH AN ISOLATED TORNADO THREAT
COULD RETURN MAINLY IN THE FAR SOUTHEAST, INCLUDING THE SOUTHERN
JAMES RIVER VALLEY OF ND.
GULF MOISTURE WILL BE, AT LEAST TEMPORARILY, CUT OFF BEHIND THE
FRONTAL BOUNDARY. HOWEVER, A DEEPENING LOW PRESSURE OVER THE
CENTRAL PLAINS COULD BRING THE RETURN OF SHOWERS AND
THUNDERSTORMS MAINLY TO SOUTHERN NORTH DAKOTA THURSDAY THROUGH
FRIDAY. THE SEVERE THREAT IS FAVORED TO REMAIN SOUTH FOR THE
MOST PART AT THIS TIME, THOUGH WILL KEEP AN EYE ON THAT OVER THE
NEXT COUPLE DAYS. SATURDAY IS FAVORED TO REMAIN MOSTLY DRY,
AFTER WHICH PERIODIC SHOWERS AND THUNDERSTORMS ARE POSSIBLE TO
START NEXT WEEK. CSU MACHINE LEARNING SUGGESTS AT LEAST LOW
SEVERE WEATHER POTENTIAL MOST DAYS TO START NEXT WEEK.
SLIGHTLY ABOVE AVERAGE TEMPERATURES WITH HIGHS IN THE MID 70S TO
LOW 80S ARE EXPECTED TO CONTINUE THROUGH FRIDAY. WELL ABOVE
AVERAGE TEMPERATURES ARE THEN EXPECTED TO RETURN THIS WEEKEND
AND ARE FAVORED TO CONTINUE INTO THE MIDDLE OF NEXT WEEK. LOWS
WILL START OUT MOSTLY IN THE MID 40S TO LOW 50S BEFORE
INCREASING TO THE 50S TO LOW 60S NEXT WEEK.
AVIATION /00Z TAFS THROUGH 00Z THURSDAY/
ISSUED AT 641 PM CDT TUE JUN 2 2026
SHOWERS AND THUNDERSTORMS CONTINUE ALONG A COLD FRONTAL BOUNDARY
THAT IS DRAPED ACROSS CENTRAL NORTH DAKOTA FROM JUST EAST OF
KBIS NORTHEASTWARD TO JUST EAST OF LANGDON. NEAR THIS FRONT,
EXPECT THE POTENTIAL FOR ADDITIONAL SHRAS/TSRAS...SOME OF WHICH
COULD BE SEVERE...TO IMPACT POTENTIALLY KJMS AMD KBIS OVER THE
NEXT FEW HOURS WITH MVFR OF LOWER CIGS/VSBYS. SHRA/TSRA ACTIVITY
IS THEN EXPECTED TO SHIFT EAST WITH THE COLD FRONT AS IT
EXPANDS IN COVERAGE THROUGH AROUND 03/06Z...WITH ADDITIONAL
SHRAS/TSRAS ROTATING AROUND THE UPPER LEVEL LOW ACROSS SOUTHERN
SASKATCHEWAN IMPACTING THE WESTERN TERMINALS OVERNIGHT AND
WORKING ITS WAY EASTWARD DURING THE DAYTIME HOURS WEDNESDAY.
OVERALL, AN UNSETTLED PERIOD WITH LOW CONFIDENCE IN TIMING OF
TSRA ACTIVITY AND THEREFORE LIMITED LOWER CIGS/VSBYS TO MAINLY
PROB30 GROUPS.
BIS WATCHES/WARNINGS/ADVISORIES
NONE.
UPDATE...CJS
DISCUSSION...TELKEN
AVIATION...ROSSI
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