259
FXUS63 KBIS 241153
AFDBIS
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BISMARCK ND
653 AM CDT MON AUG 24 2026
KEY MESSAGES
- ISOLATED TO SCATTERED SEVERE THUNDERSTORMS COULD DEVELOP IN
CENTRAL AND EASTERN NORTH DAKOTA THIS AFTERNOON AND EVENING.
THERE ARE HIGHER CHANCES FOR STORMS DEVELOPING IN EASTERN
NORTH DAKOTA THAN CENTRAL.
- POTENTIAL HAZARDS FROM SEVERE STORMS THIS AFTERNOON AND
EVENING INCLUDE LARGE HAIL UP TO 2 INCHES IN DIAMETER AND
DAMAGING WINDS UP TO 70 MPH, WITH A TORNADO POSSIBLE IN THE
JAMES RIVER VALLEY EARLY THIS EVENING.
- NEAR-CRITICAL FIRE WEATHER CONDITIONS ARE EXPECTED ACROSS MUCH
OF WESTERN NORTH DAKOTA THIS AFTERNOON AND EARLY EVENING, AND
COULD RETURN TO FAR SOUTHWEST PARTS OF THE STATE ON TUESDAY.
- A LITTLE WARMER TODAY, THEN COOLER AND WINDY ON TUESDAY. NEAR
TO SLIGHTLY ABOVE AVERAGE TEMPERATURES ARE FAVORED FROM THE
MIDDLE OF THE WEEK THROUGH THE WEEKEND.
UPDATE
ISSUED AT 645 AM CDT MON AUG 24 2026
WIDELY SCATTERED SHOWERS AND THUNDERSTORMS CONTINUE TO MOVE
THROUGH THE STATE THIS MORNING, WITH CONCENTRATED AREAS BETWEEN
GARRISON AND MINOT, ROLLA AND RUGBY, AND CARRINGTON AND
COOPERSTOWN AS OF 645 AM CDT. THE RISK FOR SEVERE WEATHER IS
VERY LOW FOR THE REST OF THE MORNING.
DISCUSSION
ISSUED AT 520 AM CDT MON AUG 24 2026
A DEEP UPPER LOW IS SPINNING FROM SOUTHERN ALBERTA INTO
SOUTHERN SASKATCHEWAN EARLY THIS MORNING, WITH AN ATTENDANT
SURFACE TROUGH EXTENDING FROM THE SURFACE LOW OVER CENTRAL
SASKATCHEWAN THROUGH WESTERN NORTH DAKOTA. A PRECEDING LOWER-
AMPLITUDE SHORTWAVE IS TRAVELING ALONG THE NORTH DAKOTA-
MANITOBA BORDER AND HAS BEEN RESPONSIBLE FOR THUNDERSTORMS
PRODUCING EXCESSIVE RAINFALL, ESPECIALLY FROM AROUND BOTTINEAU
TO RUGBY. GROUND-TRUTH RAIN AMOUNTS AROUND 4 INCHES HAVE BEEN
REPORTED, AND MRMS IS ESTIMATING NEAR 6 INCHES LOCALLY. AS OF 5
AM CDT, THE THREAT FOR TORRENTIAL RAINFALL HAS EXITED OUR
FORECAST AREA. FARTHER UPSTREAM, ISOLATED SHOWERS AND STORMS
THAT ARE LIKELY BEING MAINTAINED BY A PLUME OF LOW LEVEL WARM
AIR ADVECTION ARE MOVING FROM NORTHWEST INTO NORTH CENTRAL
NORTH DAKOTA. THESE HAVE MOSTLY BEEN BENIGN AND WERE BEGINNING
TO RAPIDLY DIMINISH AS OF 5 AM CDT, BUT EARLIER IN THE NIGHT
THERE WAS A ROGUE 58 MPH WIND GUST AT AN NDAWN STATION NEAR
RAY. THE MAGNITUDE OF WARM AIR ADVECTION IS FORECAST TO
DECREASE LATER THIS MORNING, WHICH COULD ALLOW THIS ACTIVITY TO
CONTINUE TO DISSIPATE. A FEW CAMS HINT AT REDEVELOPMENT OF WEAK
ELEVATED CONVECTION IN NORTHWEST NORTH DAKOTA LATER THIS
MORNING, LIKELY IN RESPONSE TO HEIGHT FALLS FROM THE
SASKATCHEWAN LOW, BUT MORE RECENT CAMS HAVE BACKED OFF ON THIS
POTENTIAL.
STILL LOOKING AT A CONDITIONAL THREAT FOR SEVERE THUNDERSTORMS
IN CENTRAL AND EASTERN NORTH DAKOTA ALONG AND AHEAD OF THE
EASTWARD ADVANCING SURFACE TROUGH THIS AFTERNOON AND EVENING,
WITH UNCERTAINTY ROOTED IN WHETHER THERE WILL BE STRONG ENOUGH
FORCING TO OVERCOME CIN. THE MOST RECENT SUITE OF CAMS IS MORE
CONFIDENT THAT CONVECTIVE INITIATION WILL OCCUR AT SOME POINT
AND TIME, BUT IT MAY NOT BE UNTIL CLOSER TO EARLY EVENING WHEN
THE FRONTAL BOUNDARY REACHES THE JAMES RIVER VALLEY. THE SPC
HAS INTRODUCED A SLIGHT RISK (LEVEL 2 OUT OF 5) TO THE EASTERN
THIRD OF THE STATE, REACHING AS FAR WEST AS THE JAMES RIVER
VALLEY. A DISCRETE STORM MODE IS FAVORED, BUT SPLITTING
SUPERCELLS/STORM MERGERS COULD CONTRIBUTE TO UPSCALE GROWTH
AND/OR CLUSTERING OF STORMS. CAPE IN THE 2000-3000 J/KG RANGE
AND DEEP LAYER SHEAR AROUND 35-40 KTS WILL BE SUPPORTIVE OF
VERY LARGE HAIL TO AROUND 2 INCHES IN DIAMETER. THE AMOUNT OF
SHEAR AND HIGH FORECAST DCAPE ALSO LEAVES OUR MOST LIKELY
MAXIMUM WIND GUST FORECAST AT 70 MPH. DID ELECT TO BEGIN
MESSAGING A POSSIBLE TORNADO, WHICH WOULD MOST LIKELY BE
LIMITED TO THE JAMES RIVER VALLEY IN THE EARLY EVENING WHEN AND
WHERE THE COMBINATION OF STRONGER LOW LEVEL SHEAR/SRH AND
WEAKER MLCIN IS MAXIMIZED.
TODAY WILL BE SEASONABLY WARM, WITH HIGHS IN THE LOWER 80S TO
LOWER 90S. A MUCH DRIER AIR MASS AND GUSTY WEST-NORTHWEST WINDS
BEHIND THE SURFACE TROUGH WILL CREATE NEAR-CRITICAL FIRE
WEATHER CONDITIONS THIS AFTERNOON AND EARLY EVENING, ESPECIALLY
FROM NEAR WILLISTON TO BOWMAN. THE CANADIAN LOW WILL SPIN INTO
SOUTHERN MANITOBA ON TUESDAY BEFORE DIVING SOUTHEAST TOWARD THE
WESTERN GREAT LAKES. THIS WILL LEAVE COOLER TEMPERATURES AND
WINDY CONDITIONS OVER THE NORTHERN PLAINS ON TUESDAY, WITH
HIGHS IN THE MID 70S TO LOWER 80S AND NORTHWEST WINDS AROUND 20
TO 30 MPH, GUSTING AS HIGH AS 40 MPH. RH MAY FALL LOW ENOUGH IN
THE FAR SOUTHWEST FOR ANOTHER AFTERNOON OF NEAR-CRITICAL FIRE
WEATHER CONDITIONS ON TUESDAY. THERE COULD ALSO BE SOME
DIURNALLY-DRIVEN AFTERNOON SHOWERS IN THE CYCLONIC FLOW REGIME
ON TUESDAY. THE NBM LIMITS THIS POTENTIAL TO THE TURTLE
MOUNTAINS, BUT SOME RUNS OF THE HRRR HAVE BROUGHT ISOLATED
SHOWERS AS FAR SOUTH AS THE NORTHERN JAMES RIVER VALLEY.
BROAD SURFACE HIGH PRESSURE IS FORECAST OVER THE REGION ON
WEDNESDAY AS THE UPPER LEVEL RIDGE RE-AMPLIFIES OVER THE
ROCKIES. GUIDANCE THEN FAVORS THE RIDGE AXIS BEING SHOVED
EASTWARD ON THURSDAY AS A DEEPER TROUGH DIGS INTO THE PACIFIC
NORTHWEST. SHORTWAVE ENERGY EJECTING FROM THE BASE OF THAT
TROUGH BRINGS SHOWER AND THUNDERSTORM CHANCES BACK TO THE
REGION AS EARLY AS THURSDAY NIGHT, WITH NEAR-DAILY LOW TO
MEDIUM CHANCES CONTINUING THROUGH THE WEEKEND AS A MORE
PROGRESSIVE SYNOPTIC PATTERN EMERGES. TEMPERATURES ARE FAVORED
TO REMAIN NEAR AVERAGE OVERALL, BUT COULD TREND SLIGHTLY ABOVE
AVERAGE CLOSER TO THE END OF THE WEEK.
AVIATION /12Z TAFS THROUGH 12Z TUESDAY/
ISSUED AT 645 AM CDT MON AUG 24 2026
A FEW SHOWERS AND THUNDERSTORMS REMAIN POSSIBLE ACROSS NORTHERN,
CENTRAL, AND EASTERN NORTH DAKOTA THIS MORNING. LATER THIS
AFTERNOON AND EVENING, ISOLATED TO SCATTERED SEVERE
THUNDERSTORMS PRODUCING LARGE HAIL AND DAMAGING WINDS COULD
DEVELOP IN THE EASTERN HALF OF THE STATE. A PROB30 MENTION FOR
A SEVERE STORM HAS BEEN ADDED TO THE KJMS TAF THIS EVENING.
OUTSIDE OF SHOWERS AND THUNDERSTORMS, VFR CONDITIONS ARE
EXPECTED THROUGH THE FORECAST PERIOD. WINDS WILL BECOME WEST TO
NORTHWEST IN WESTERN NORTH DAKOTA THIS AFTERNOON AROUND 15-20
KTS, WITH GUSTS TO AROUND 30 KTS IN THE NORTHWEST. CENTRAL
NORTH DAKOTA SHOULD SEE SOUTHERLY TO WESTERLY WINDS REMAIN
CLOSER TO 10 KTS THROUGH THE DAY.
BIS WATCHES/WARNINGS/ADVISORIES
NONE.
UPDATE...HOLLAN
DISCUSSION...HOLLAN
AVIATION...HOLLAN
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