342
FXUS63 KBIS 130547
AFDBIS
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BISMARCK ND
1247 AM CDT THU AUG 13 2026
KEY MESSAGES
- SCATTERED SHOWERS AND A FEW THUNDERSTORMS OVERNIGHT, WITH
DAILY CHANCES FOR SHOWERS AND THUNDERSTORMS CONTINUING THROUGH
FRIDAY NIGHT.
- A COOLING TREND IS EXPECTED THROUGH FRIDAY, FOLLOWED BY A
WARMING TREND THROUGH THE WEEKEND AND INTO EARLY NEXT WEEK.
UPDATE
ISSUED AT 1216 AM CDT THU AUG 13 2026
SHOWERS AND ISOLATED THUNDERSTORMS CONTINUE ACROSS THE NORTH
AND THE FAR SOUTH CENTRAL INTO THE JAMES RIVER VALLEY. ACTIVITY
CONTINUES TO WANE SLOWLY AS JET ENERGY NORTH AND LLJ SOUTH ALSO
MOVE AWAY AND DISSIPATE. MADE SOME MINOR ADJUSTMENTS TO POPS
AND SKY COVER. OTHERWISE NO CHANGES TO THE GOING FORECAST.
UPDATE
ISSUED AT 930 PM CDT WED AUG 12 2026
THUNDERSTORM ACTIVITY HAS GREATLY DIMINISHED ACROSS WESTERN AND
CENTRAL NORTH DAKOTA AT THE TIME OF THIS MID TO LATE EVENING
UPDATE. SHOWERS AND A FEW ISOLATED STORMS CONTINUE ACROSS
GENERALLY ALONG AND SOUTH OF I-94 TO THE EAST OF DICKINSON, WITH
THE GREATEST ACTIVITY COLLOCATED WITH AN AXIS OF 300MB
DIVERGENCE ACROSS THE FAR SOUTHERN JAMES RIVER VALLEY INTO
NORTHEASTERN SOUTH DAKOTA AT THIS TIME. A FEW MORE ATTEMPTS AT
CONVECTION HAVE OCCURRED FURTHER TO THE NORTH BETWEEN WASHBURN
AND JAMESTOWN, THOUGH WITH CIN RAPIDLY INCREASING ACROSS THE
BOARD AND BEING DISPLACED FROM THE BETTER FORCING TO THE SOUTH,
NO MUCH MORE THAN AN ISOLATED RUMBLE OF THUNDER OR TWO HAS BEEN
FORTHCOMING. IN THE NORTHWEST, THE PREVIOUSLY MENTIONED SHOWERS
AND STORMS IN MONTANA HAVE STRUGGLED TO MAKE THEIR WAY
INTO OUR WEST WITH THE LIMITED CAPE (GENERALLY LESS THAN 500
J/KG) BECOMING INCREASINGLY UNBALANCED WITH THE STRONG BULK
SHEAR (AROUND 50 TO 55 KNOTS) IN THAT REGION. AT LEAST SOME
THUNDER IS EXPECTED TO CONTINUE INTO THE EARLY OVERNIGHT PERIOD,
THOUGH COVERAGE IS EXPECTED TO BECOME INCREASINGLY LIMITED.
FURTHER ALONG THE INTERNATIONAL BORDER, SCATTERED MODERATE
REFLECTIVITIES HAVE DEVELOPED ALONG THE RIGHT ENTRANCE REGIONS
OF A MID LEVEL JET DIPPING DOWN OUT OF CANADA. A NEAR
NONEXISTENT CONVECTIVE ENVIRONMENT IS EXPECTED TO KEEP THESE AS
MAINLY SHOWERS, THOUGH AGAIN SOME ISOLATED LIGHTNING IS NOT
IMPOSSIBLE ACROSS PORTIONS OF THE NORTH CENTRAL THROUGH THE
EARLY EVENING. WITH THIS UPDATE, HAVE EXTENDED LOW POPS FURTHER
ACROSS NORTH CENTRAL NORTH DAKOTA TO ACCOUNT FOR THE DEVELOPMENT
OF SHOWERS ALONG THIS MID LEVEL JET, AND TO ACCOUNT FOR THE
LATEST MODEL TRENDS. OTHERWISE, THE FORECAST REMAINS IN GOOD
SHAPE THIS EVENING.
UPDATE
ISSUED AT 700 PM CDT WED AUG 12 2026
SHOWERS AND THUNDERSTORMS HAVE LIFTED INTO PORTIONS OF WESTERN
AND SOUTH CENTRAL NORTH DAKOTA BY THE TIME OF THIS EARLY EVENING
UPDATE. A FAIRLY MARGINAL AND UNBALANCED CONVECTIVE ENVIRONMENT
IS FOUND OVER THE FORECAST AREA, WITH MESOANALYSIS REVEALING
SOMEWHAT MODEST MUCAPE VALUES AROUND 500 TO 1250 J/KG, BUT
FAIRLY STRONG 0-6KM BULK SHEAR VALUES AROUND 45 TO 55 KNOTS
ACROSS ALONG AND SOUTH OF HIGHWAY 200. THE CONVECTIVE
ENVIRONMENT REMAINS THE BEST ACROSS THE SOUTH CENTRAL, WHERE A
STRONG TO SEVERE STORMS HAVE DEVELOPED OVER THE COURSE OF THE
LAST FEW HOURS. HERE, THE HIGHEST MID LEVEL LAPSE RATES OF
6.0-6.5 C/KM HAVE BEEN MORE SUPPORTIVE OF LARGE HAIL PRODUCTION,
AND FAIRLY STRAIGHT LOW LEVEL HODOGRAPHS HAVE ALLOWED FOR THE
OCCASIONAL, SHORT- LIVED LEFT-SPLIT SUPER CELL (WHICH ARE
USUALLY MORE PROLIFIC HAIL PRODUCERS). WITH CONDITIONS FURTHER
EAST STARTING TO BECOME WORKED OVER BY EARLIER SHOWERS AND
STORMS, AND WHERE THE CONVECTIVE HAS ALREADY BEEN MORE MARGINAL
THROUGHOUT THE EVENING, MORE DISORGANIZED, CLUSTERED STORMS HAVE
BEEN FOUND. CELL MERGERS BETWEEN THESE STORMS OR INTERACTIONS
WITH A FEW OUTFLOW BOUNDARIES MOVING TO THE NORTHWEST HAVE
ALLOWED A FEW STRONGER STORMS TO DEVELOP, THOUGH EVEN THESE HAVE
BEEN FAIRLY SHORT LIVED. UPSTREAM IN MONTANA, ANOTHER ROUND OF
SHOWERS AND STORMS ARE SLOWLY MAKING THEIR WAY TOWARD OUT
WESTERN BORDER, ARRIVING SOME TIME WITHIN THE NEXT TWO HOURS OR
SO. HAVE TWEAKED POPS, WINDS, AND SKY COVER WITH THIS UPDATE TO
ACCOUNT FOR THE LATEST RADAR, MODEL, AND SATELLITE TRENDS.
DISCUSSION
ISSUED AT 225 PM CDT WED AUG 12 2026
CURRENTLY NEAR ZONAL FLOW EXIST OVER THE NORTHERN PLAINS WITH A
SLIGHT SOUTHWEST TILT OVER MONTANA. A TROUGH AND UPPER LOW DIGS
THROUGH WASHINGTON STATE AT THIS TIME. AT THE SURFACE A LOW
SITS IN EASTERN WYOMING WITH AN INVERTED TROUGH THROUGH EASTERN
MONTANA WITH SHOWERS AND THUNDERSTORMS AROUND THE LOW.
TODAY WE ARE IN ANOTHER SEVERE RISK, THIS TIME JUST A LEVEL 1
ACROSS THE SOUTHERN HALF OF THE STATE. GLOBAL MODELS HAVE 1000
TO 2000 J/KG OF MUCAPE WITH 45 TO 50KTS OF SHEAR. THE ACTUAL 18Z
SOUNDING FROM BISMARCK SHOWS 1900 J/KG OF CAPE FROM THE SURFACE
WITH VERY LITTLE CIN AND 53 KTS OF SHEAR. HAZARDS TODAY COULD
BE GOLF BALL SIZE HAIL WITH ALL THAT SHEAR AND 60 MPH WINDS. SO
FAR VERY LIGHT RAIN FROM THE LOW PRESSURE IS IN THE SOUTHWEST
WITH THUNDERSTORMS IN SOUTHEAST MONTANA. A FEW FAILING STORMS
ARE TRYING IN SOUTH CENTRAL NORTH DAKOTA. THE FORCING AND
INDICATOR FOR WHERE THE SEVERE STORMS WILL BE IS THE RIGHT
ENTRANCE REGION OF THE JET STREAK. CURRENTLY THAT AREA IS OVER
SOUTHEASTERN MONTANA, ENTERING INTO SOUTHWEST NORTH DAKOTA.
LOOKING AT RADAR NEW STORMS ARE QUICKLY GROWING IN SOUTHEAST
MONTANA. THAT JET STREAK IS FORECAST TO MOVE EAST WITH THE RIGHT
ENTRANCE REGION STAYING ALONG THE SOUTH DAKOTA BORDER. AFTER
00Z, MODELS WANT TO PULL MOST OF THE CAPE OUT OF THE STATE AND
INTO EASTERN SOUTH DAKOTA AS THE SURFACE LOW MOVES EAST. AFTER
THIS EVENING SHOWERS AND MAYBE A THUNDERSTORM ARE POSSIBLE
THROUGH THE NIGHT.
THE REST OF THIS WEEK THE FLOW WILL TURN SOUTHWEST AND THE
TROUGH CONTINUING TO DIG INTO THE WEST CONUS. THIS, IN TURN,
WILL PRODUCE DAILY CHANCES OF SHOWERS AND THUNDERSTORMS THROUGH
FRIDAY NIGHT, WITH THE HIGHEST CHANCES ACROSS THE WEST EVERYDAY.
TEMPERATURES WILL CONTINUE TO REMAIN AT OR BELOW NORMAL IN THE
70S AND LOWER 80S THROUGH SATURDAY. SLIGHT NORTHWEST FLOW
RETURNS THIS WEEKEND WITH A SLIGHT RIDGE TO START NEXT WEEK.
THEREFORE NORMAL TEMPERATURES IN THE 80S WILL RETURN.
AVIATION /06Z TAFS THROUGH 06Z FRIDAY/
ISSUED AT 1216 AM CDT THU AUG 13 2026
MAINLY VFR CONDITIONS EXPECTED TO BEGIN THE 06Z TAF PERIOD. HOWEVER,
KDIK WAS REPORTING SOME FOG. LOW STRATUS AND FOG WILL BE
POSSIBLE ACROSS THE AREA OVERNIGHT AND INTO THURSDAY MORNING,
ESPECIALLY IN THE SOUTHWEST AND SOUTH CENTRAL. INCLUDED A
PERIOD OF IFR-LIFR CIGS/VSBYS AT KDIK AROUND 12 UTC. ISOLATED
SHOWERS AND THUNDERSTORMS CONTINUE TO TRACK ACROSS NORTHERN ND
INCLUDING KXWA AND KDIK. HAVE INCLUDED A VCSH FOR KXWA AND A
VCTS FOR KMOT. AFTER THE OVERNIGHT SHOWER ACTIVITY MOST AREAS
SHOULD REMAIN DRY ON THURSDAY BUT WILL SEE INCREASING CHANCES
FOR SHOWERS AT KXWA, ESPECIALLY AFTER 00Z FRIDAY, WITH AREAS OF
MVFR CEILINGS AFTER 00Z AS WELL.
BIS WATCHES/WARNINGS/ADVISORIES
NONE.
UPDATE...TWH
DISCUSSION...SMITH
AVIATION...TWH
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