283
FXUS63 KBIS 301829
AFDBIS
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BISMARCK ND
129 PM CDT SUN AUG 30 2026
KEY MESSAGES
- SCATTERED SEVERE STORMS ARE POSSIBLE LATER THIS AFTERNOON INTO
TONIGHT. MAIN HAZARDS WILL BE UP TO GOLFBALL SIZE HAIL, UP TO
75 MPH WIND GUSTS, AND MAYBE A TORNADO OR TWO. LOCALLY HEAVY
RAINFALL IS ALSO POSSIBLE.
- DRY AND WINDY CONDITIONS ARE FORECAST FOR MONDAY. LOCATIONS
ALONG AND NORTH OF US-2 MAY EXPERIENCE WIND GUSTS BETWEEN 45
AND 55 MPH. ADDITIONALLY, NEAR CRITICAL TO CRITICAL FIRE
WEATHER CONDITIONS ARE POSSIBLE ACROSS PORTIONS OF WESTERN
NORTH DAKOTA.
- ADDITIONAL PERIODIC CHANCES FOR SHOWERS AND THUNDERSTORMS
REMAINS IN THE FORECAST FROM TUESDAY EVENING INTO NEXT
WEEKEND. BEST CHANCES FOR SHOWERS AND STORMS WILL BE WEDNESDAY
NIGHT INTO THURSDAY MORNING.
UPDATE
ISSUED AT 1232 PM CDT SUN AUG 30 2026
MUCH OF WESTERN NORTH DAKOTA HAS CLEARED OUT FROM THE LOW STRATUS
AND FOG FROM THIS MORNING, AND DESTABILIZATION IS OCCURRING THANKS
TO AMPLE DIURNAL HEATING. A COUPLE OF ISOLATED THUNDERSTORMS HAVE
DEVELOPED IN THE FAR NORTHWEST CORNER OF NORTH DAKOTA, BUT THIS
ACTIVITY REMAINS SUB-SEVERE, AND IS PROGRESSING NORTHWARD INTO
CANADA. MEANWHILE, THE COLD FRONT IS CONTINUING EASTWARD ACROSS
MONTANA HAVING RECENTLY PASSED THROUGH THE BILLINGS AREA. ASSOCIATED
SHOWERS AND STORMS ARE CURRENTLY PRODUCING WIND GUSTS BETWEEN 35 AND
50 MPH. THE EXPECTATION CONTINUES TO BE THAT THUNDERSTORMS WILL
ORGANIZE INTO A LINE ALONG THIS FRONTAL BOUNDARY AS IT PROGRESSES
EASTWARD INTO A MUCH MORE UNSTABLE AIR MASS. THE MAIN CONCERN FOR
THIS AFTERNOON INTO TONIGHT WILL BE DAMAGING WINDS UP TO 75 MPH;
HOWEVER, ANY STORMS THAT CAN BE SEMI-DISCRETE COULD POSE A LARGE
HAIL THREAT. A BRIEF TORNADO OR TWO CANNOT BE RULED OUT AS WELL.
DISCUSSION
ISSUED AT 128 PM CDT SUN AUG 30 2026
ALL EYES ARE ON THE APPROACHING VIGOROUS UPPER LOW/TROUGH LOCATED
OVER SOUTHERN ALBERTA/NORTHERN MONTANA EARLY THIS AFTERNOON. A SHARP
TROUGH AXIS IS ROUNDING THE SOUTHERN PERIPHERY OF THIS UPPER LOW,
AND THE ATTENDANT UPPER JET MAX WILL ARRIVE OVER EASTERN
MONTANA/WESTERN NORTH DAKOTA LATER THIS AFTERNOON. AT THE SURFACE, A
SHARP FRONTAL BOUNDARY IS SWEEPING EASTWARD ACROSS MONTANA, AND
THUNDERSTORM DEVELOPMENT HAS ALREADY ONGOING ALONG THIS FRONTAL
BOUNDARY AS OF 18Z. CLEARING OF LOW STRATUS AND PATCHY FOG,
ALONG WITH LIMITED COVERAGE OF HIGH CLOUDS, HAS ALLOWED FOR
DESTABILIZATION OF THE ATMOSPHERE ACROSS MUCH OF NORTH DAKOTA.
AS OF 18Z SPC MESOANALYSIS SUGGESTS 1500-2000 J/KG MLCAPE EXISTS
ACROSS THE NORTHERN AND WESTERN PORTIONS OF THE STATE EAST OF A
PSEUDO- DRYLINE THAT IS GENERALLY IN THE VICINITY OF THE MT/ND
STATELINE. ADDITIONALLY, A WARM FRONT IS DRAPED FROM NORTHWEST
TO SOUTHEAST ACROSS THE STATE WITH BACKED EASTERLY/SOUTHEASTERLY
LOW-LEVEL FLOW ALONG IT. AS THE COLD FRONT AND ACCOMPANYING
LINE OF SHOWERS AND STORMS CONTINUES EASTWARD, IT WILL RUN INTO
THIS UNSTABLE AIRMASS AND LIKELY BECOME SEVERE (IF IT'S NOT
ALREADY). GENERALLY SPEAKING, THE ENVIRONMENT ACROSS THE WESTERN
2/3RDS OF THE STATE WILL SUPPORT WIND GUSTS UP TO 75 MPH. IN
ADDITION, WITH EFFECTIVE SHEAR EXPECTED TO BE IN THE
NEIGHBORHOOD OF 30 KNOTS, ANY STORM THAT CAN BECOME SEMI-
DISCRETE MAY POSE A LARGE HAIL THREAT WITH UP TO GOLFBALL SIZE
HAIL POSSIBLE. LASTLY, BACKED LOW-LEVEL FLOW ALONG THE WARM
FRONT WILL MODESTLY ENLARGE LOW-LEVEL HODOGRAPHS POSING AN
ISOLATED TORNADO THREAT AS THE LINE OF STORMS SWEEPS ACROSS THE
STATE. ONE QUIRK IN TODAY'S FORECAST IS THAT A VERY TIGHT
PRESSURE GRADIENT WILL ACCOMPANY THIS COLD FRONT. THEREFORE, IT
MAY BE POSSIBLE SOME LOCATIONS SEE VERY LITTLE RAINFALL WHILE
EXPERIENCING A BRIEF PERIOD OF STRONG WINDS, ESPECIALLY ACROSS
WESTERN NORTH DAKOTA WHERE THE AIRMASS IS EXPECTED TO BE MUCH
DRIER THAN THE REST OF THE STATE.
THE SURFACE LOW AND UPPER LOW ARE STILL FORECAST TO BECOME
VERTICALLY STACKED OVER SASKATCHEWAN AND WILL STRENGTHEN MONDAY
MORNING. A RESULTING TIGHT PRESSURE GRADIENT WILL RESIDE ALONG THE
INTERNATIONAL BORDER AND INTO MUCH OF NORTH DAKOTA MONDAY MORNING
INTO EARLY MONDAY AFTERNOON. THE LATEST EFI, ALONG WITH
DETERMINISTIC GUIDANCE, CONTINUES TO TREND UPWARDS WITH THE
POTENTIAL FOR STRONG WIND GUSTS ACROSS FAR NORTHERN PORTIONS OF THE
STATE. AMPLE DIURNAL HEATING SHOULD ALLOW FOR A DEEPLY MIXED
BOUNDARY LAYER, AND UNIFORM FLOW IN SAID BOUNDARY LAYER SHOULD ALLOW
FOR STRONG WINDS ALOFT TO BE EFFICIENTLY TRANSFERRED TO THE SURFACE.
GUIDANCE CONTINUES TO SHOW 850 MB WINDS IN THE 45 TO 55-KNOT RANGE.
ASSUMING OPTIMAL CONDITIONS, 45 TO 55 MPH WIND GUSTS APPEAR LIKELY
ACROSS NORTHERN NORTH DAKOTA DURING THE DAY ON MONDAY. A WIND
ADVISORY HAS BEEN HOISTED FOR THIS POTENTIAL ACROSS NORTHERN
PORTIONS OF THE STATE. LATE AFTERNOON INTO EARLY EVENING, THE
PRESSURE GRADIENT IS FORECAST TO RELAX, AND WIND SPEEDS AND GUSTS
SHOULD GRADUALLY WEAKEN THROUGH THE EVENING AND NIGHTTIME HOURS. IN
ADDITION TO THE WINDY CONDITIONS, A MUCH DRIER POST-FRONTAL AIRMASS
IS EXPECTED TO OVERSPREAD MUCH OF THE NORTHERN PLAINS. LOCATIONS
ACROSS WESTERN NORTH DAKOTA COULD SEE MINIMUM RH VALUES AROUND 20-
25% DURING THE DAY ON MONDAY. AS A RESULT OF THESE DRY AND WINDY
CONDITIONS, NEAR-CRITICAL TO CRITICAL FIRE WEATHER CONDITIONS ARE
APPEARING INCREASINGLY LIKELY ACROSS WESTERN NORTH DAKOTA. THE MAIN
CAVEAT TO POTENTIAL FIRE WEATHER CONCERNS IS THAT RECENT RAINFALL
WILL LIKELY MITIGATE THE VOLATILITY OF FUELS SOMEWHAT,
THEREFORE, A RED FLAG WARNING IS NOT ANTICIPATED AT THIS TIME.
PERIODIC CHANCES FOR SHOWERS AND STORMS REMAINS IN THE FORECAST FROM
TUESDAY THROUGH THE END OF NEXT WEEK. MID TO LONG RANGE GUIDANCE
CONTINUES TO BE ON BOARD WITH A SERIES OF SYSTEMS TRAVERSING THE
NORTHERN PLAINS AROUND MID/UPPER RIDGING REMAINING OVER THE CENTRAL
AND SOUTHERN PLAINS. THE BEST CHANCES FOR SHOWERS AND STORMS NEXT
WEEK WILL LIKELY BE WEDNESDAY NIGHT INTO THURSDAY MORNING AS A STOUT
UPPER TROUGH IS FORECAST TO EJECT INTO THE NORTHERN PLAINS. A BRIEF
BREAK IS POSSIBLE HEADING INTO THE WEEKEND, WITH ONLY LOW (UNDER
20%) CHANCES RETURNING BY LATE SATURDAY INTO EARLY SUNDAY. AT THIS
TIME, SEVERE WEATHER IS NOT EXPECTED FOR DURING THESE PERIODS.
AVIATION /18Z TAFS THROUGH 18Z MONDAY/
ISSUED AT 1232 PM CDT SUN AUG 30 2026
STRATUS CONTINUES TO LIFT ACROSS MUCH OF NORTHWEST AND CENTRAL ND TO
BEGIN THE 18Z TAF PERIOD. KDIK HAS CLEARED, WITH MVFR STRATUS
LIFTING AND DISSIPATING BUT STILL LINGERING AROUND THE REMAINING TAF
SITES. EXPECT THE STRATUS TO LIFT/DISSIPATE AT ALL SITES BY 20 UTC.
SOUTHEAST SURFACE FLOW ALSO REMAINS AT ALL TAF SITES TO BEGIN THE
PERIOD, BUT A LOW PRESSURE SYSTEM ALONG THE ND/MT BORDER WILL PUSH
EAST AND SHIFT WINDS WESTERLY THIS AFTERNOON THROUGH THIS EVENING.
WINDS HAVE JUST SHIFTED WESTERLY IN FAR WESTERN ND. IN ADDITION TO
THE WIND SHIFT, THUNDERSTORMS ARE EXPECTED TO INCREASE IN COVERAGE
AND INTENSITY OVER EASTERN MT AND WESTERN ND THIS AFTERNOON, AND
SPREADING EAST ACROSS WESTERN AND CENTRAL ND THIS EVENING. SOME OF
THESE STORMS WILL BE STRONG TO SEVERE WITH DAMAGING WINDS AND LARGE
HAIL POSSIBLE. ANY STORM WILL ALSO HAVE THE POTENTIAL TO PRODUCE
MVFR CEILINGS AND IFR-MVFR VISIBILITIES. THE LINE IS EXPECTED TO
MOVE PRETTY QUICKLY EAST LATE THIS AFTERNOON AND THIS EVENING, SO
THE DURATION OF THUNDERSTORMS AT ANY ONE SITE WILL BE RATHER SHORT.
ON MONDAY LOOK FOR INCREASING SOUTHWEST TO WESTERLY WINDS BY MID TO
LATE MORNING, STRONGEST ACROSS THE NORTHERN TAF SITES OF KXWA AND
KMOT, ESPECIALLY AFTER THE 18Z TAF PERIOD
BIS WATCHES/WARNINGS/ADVISORIES
WIND ADVISORY FROM 10 AM CDT /9 AM MDT/ TO 7 PM CDT /6 PM MDT/
MONDAY FOR NDZ001>005-009-010-012-013-017-055-056.
UPDATE...JC
DISCUSSION...JC
AVIATION...TWH
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