413
FXUS63 KBIS 120915
AFDBIS
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BISMARCK ND
415 AM CDT WED AUG 12 2026
KEY MESSAGES
- SCATTERED THUNDERSTORMS TODAY AND THIS EVENING. ISOLATED
SEVERE STORMS ARE POSSIBLE ALONG AND SOUTH OF THE HIGHWAY 200
CORRIDOR.
- A COOLING TREND IS EXPECTED THROUGH FRIDAY, FOLLOWED BY A
WARMING TREND THROUGH THE WEEKEND AND INTO EARLY NEXT WEEK.
DISCUSSION
ISSUED AT 251 AM CDT WED AUG 12 2026
CURRENTLY, ISOLATED THUNDERSTORMS WERE LOCATED OVER SOUTH
CENTRAL ND. THIS IS WITHIN AN AREA OF 2000 J/KG OF INSTABILITY
ALOFT WITH MODERATE TO STRONG EFFECTIVE SHEAR. THE LATEST WV
IMAGERY AND UPPER LEVEL HEIGHTS SHOW AN UPPER LEVEL TROUGH OVER
THE PACIFIC NORTHWEST WITH A MEAN UPPER LEVEL RIDGE OVER CENTRAL
MONTANA. A SPEED MAX WAS LOCATED OVER EASTERN MONTANA WITH SOUTH
CENTRAL ND IN THE LEFT FRONT QUAD OF THE SHORTWAVE. THIS IS
ENOUGH FORCING TO CONTINUE TO DEVELOP ISOLATED TO SCATTERED
THUNDERSTORMS OVER SOUTH CENTRAL ND, WITH THE INSTABILITY ALOFT.
FOR TODAY, AS THIS SPEED MAX PUSHED EAST THROUGH THE STATE,
THINK THERE MAY BE A CONTINUED THREAT OF SHOWERS AND
THUNDERSTORMS THROUGH THE DAY. SPC HAS PLACED A MARGINAL RISK OF
SEVERE STORMS MAINLY ALONG AND SOUTH OF THE HIGHWAY 200
CORRIDOR TODAY. CAN'T REALLY ARGUE WITH THIS AS THE ONE THING
THAT SEEMS MOST CERTAIN THIS MORNING IS THE INSTABILITY TODAY IS
FORECAST TO BE MUCH LOWER NORTH OF THE HIGHWAY 200 CORRIDOR.
THERE MAY STILL BE SHOWERS OR A FEW THUNDERSTORMS, BUT RIGHT NOW
FORECAST SOUNDINGS DON'T SUPPORT SEVERE STORMS IN THE NORTH. AS
YOU GET SOUTH OF THE HIGHWAY 200 CORRIDOR, THINGS GET MUDDLED
PRETTY QUICKLY.
THE SOUTHWEST AND SOUTH CENTRAL LOOK TO BE THE MOST UNSTABLE
THIS AFTERNOON WITH 1500-3000 J/KG OF MUCAPE. SHEAR IS
SUFFICIENT AT AROUND 40 KNOTS, BUT INCREASES AS YOU GO NORTH
FROM SOUTHERN INTO CENTRAL AND NORTHERN ND. THERE ARE A FEW
LIMITING FACTORS. WITH THE AFOREMENTIONED SHORTWAVE THERE WILL
BE MORE CLOUDS AROUND TODAY. THE RAP ALSO INDICATES THE
POTENTIAL FOR SOME STRATUS TODAY OVER THE SOUTHERN HALF OF THE
CWA, WHICH COULD LIMIT INSTABILITY. IN GENERAL, THE INSTABILITY
MAY NOT BE AS GREAT AS YESTERDAY, WHEN WE HAD HIGHS IN THE UPPER
80S AND DEW POINTS IN THE MID AND UPPER 60S IN SOUTHWEST AND
SOUTH CENTRAL ND. TODAY WE ARE EXPECTING HIGHS IN THE LOWER TO
MID 80S WITH DEW POINT IN THE LOW TO MID 60S. HOWEVER,
INSTABILITY WILL BE SUFFICIENT AND WITH THE MODERATE TO STRONG
SHEAR, WE WILL HAVE THE POTENTIAL FOR STRONG TO SEVERE STORMS
THIS AFTERNOON INTO THIS EVENING. THE MAIN QUESTION IS WHERE AND
WHEN. WITH THE SHORTWAVE MOVING THROUGH WE SEE CONTINUED
CONVECTION OVER THE SOUTH CENTRAL EARLY THIS MORNING, AND THIS
MAY SPREAD NORTH AND EAST TODAY. THEN AS THE RRQ OF THE
SHORTWAVE MOVES ACROSS THE AREA LATER TODAY, THIS MAY PROVIDE
THE FORCING FOR ASCENT NEEDED TO INITIATE CONVECTION. THE
INTERFACE OF THE STRONG INSTABILITY TO THE SOUTH AND THE STRONG
SHEAR TO THE NORTH WOULD BE AN IDEAL AREA FOR SEVERE CONVECTION
TODAY. THE MAIN HAZARDS BEING LARGE HAIL TO GOLFBALL SIZE AND
WINDS TO 60 MPH, IF WE CAN GET A SUSTAINED UPDRAFT. THE FAR
SOUTHWEST WILL BE THE MOST UNSTABLE AND CONVECTION DEVELOPING
OVER SOUTHEAST MONTANA MAY MOVE INTO SOUTHWEST ND. THE
ENVIRONMENT WOULD BE FAVORABLE FOR QUICK DEVELOPMENT WITH STEEP
LAPSE RATES. WITH A BROAD SOUTHWEST UPPER FLOW, IT'S HARD TO SAY
WHERE AND WHEN CONVECTION MAY DEVELOP AND CAMS ARE BOUNCING
AROUND A BIT. NEVERTHELESS, THERE WILL BE A THREAT FOR STRONG TO
SEVERE STORMS TODAY.
ONCE CONVECTION ENDS TODAY/THIS EVENING, WE COOL DOWN A BIT FOR
THURSDAY AND ESPECIALLY FRIDAY. WE REMAIN IN A FAVORABLE
SOUTHWEST UPPER FLOW OVER THE FAR WEST ON THURSDAY, THEN
EVENTUALLY ACROSS THE AREA FRIDAY, BUT WITH LESS INSTABILITY,
THE THREAT FOR STRONG TO SEVERE STORMS WILL BE LOW. CURRENTLY
SPC HAS ONLY GENERAL THUNDERSTORMS FORECAST FOR THURSDAY AND
FRIDAY. AFTER FRIDAY WE BEGIN A SLOW WARMING TREND THROUGH THE
WEEKEND AND INTO NEXT WEEK. SATURDAY AND SUNDAY MAY END UP BEING
MOSTLY DRY BEFORE NEAR DAILY CHANCES FOR THUNDERSTORMS RETURN
EARLY NEXT WEEK.
AVIATION /06Z TAFS THROUGH 06Z THURSDAY/
ISSUED AT 1235 AM CDT WED AUG 12 2026
CONVECTION CURRENTLY OVER STUTSMAN COUNTY IS EXPECTED TO IMPACT
KJMS TAF AT 06Z-07Z, WITH MVFR-IFR VISIBILITIES AND MVFR
CEILINGS, ALONG WITH GUSTY AND ERRATIC WINDS. ELSEWHERE, VFR
CONDITIONS ARE EXPECTED TO BEGIN THE 06Z TAF PERIOD. LOW
STRATUS/FOG IS POSSIBLE EARLY WEDNESDAY MORNING. FOR THE TIME
BEING ONLY INCLUDED A TEMPO AT KBIS FOR LOW STRATUS, BUT
CERTAINLY CAN'T RULE OUT LOW STRATUS/FOG AT ANY TAF SITE, BUT
MAINLY THE SOUTHERN TAF SITES. ANOTHER ROUND OF THUNDERSTORMS IS
POSSIBLE AGAIN WEDNESDAY AFTERNOON AND EVENING.
BIS WATCHES/WARNINGS/ADVISORIES
NONE.
DISCUSSION...TWH
AVIATION...TWH
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