460
FXUS63 KBIS 111940
AFDBIS
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BISMARCK ND
240 PM CDT TUE AUG 11 2026
KEY MESSAGES
- LOW TO MEDIUM CHANCES (30 TO 60 PERCENT) FOR THUNDERSTORMS
THROUGH TONIGHT. ISOLATED TO SCATTERED SEVERE STORMS ARE
POSSIBLE, MAINLY IN THE SOUTH.
- SHOWERS AND THUNDERSTORMS RETURN THROUGH THE WEEK. ISOLATED
SEVERE STORMS ARE POSSIBLE IN THE SOUTH AGAIN WEDNESDAY.
- NEAR AVERAGE TEMPERATURES TODAY, WITH A COOLING TREND THEN
EXPECTED THROUGH FRIDAY, FOLLOWED BY A WARMING TREND THROUGH
THE WEEKEND AND INTO EARLY NEXT WEEK.
DISCUSSION
ISSUED AT 240 PM CDT TUE AUG 11 2026
CURRENTLY QUASI-ZONAL FLOW IS OVER THE NORTHERN PLAINS, WITH A
BROAD RIDGE OVER THE SOUTHERN PLAINS. THE SEVERE STORMS IN THE
JAMES RIVER VALLEY THIS MORNING HAVE MOSTLY MOVED INTO SOUTH
DAKOTA. AT THE SURFACE WEAK HIGH PRESSURE IS IN THE REGION.
THE SEVERE STORM RISK TODAY LOOKS VERY CONDITIONAL. THERE IS
PLENTY OF CAPE WITH DEW POINTS IN THE 60S AND 70S ACROSS THE
SOUTH, HOWEVER THE BISMARCK 18Z SOUNDING SHOWS A STRONG CAP. SO
THE MAJORITY OF THE CAPE (2727 J/KG) IS ELEVATED. WHAT MIGHT
START THE EVENT BEFORE SUNSET IS THE CONVECTIVE TEMPERATURE IS
84, HOWEVER THERE IS PLENTY WILDFIRE SMOKE ALOFT THAT MIGHT
PROHIBIT THAT. SHEAR ACROSS THE AREA IS AROUND 50KTS SO
ORGANIZED. MOST OF THE CAMS KEEP CONVECTION HAPPENING UNTIL
CLOSE TO SUNSET WHEN MAYBE THE JET STREAM SPEED MAX CONNECTS
WITH THEM. THERE IS SOME STORMS STARTING TO FIRE ON THE BLACK
HILLS, BUT THAT IS NEAR THE STATIONARY FRONT. WHATEVER BOUNDARY
KICKED OFF STORMS IN OUR EAST IS STILL THERE AND HAS SOME
CUMULUS TRYING BUT CURRENTLY HITTING THE CAP. IF OR WHEN STORMS
GO THE HAZARDS ARE 2 INCH HAIL AND 70MPH WINDS. THUNDERSTORMS
ARE POSSIBLE THROUGH TONIGHT AND INTO THE MORNING, ESPECIALLY IN
THE SOUTH CENTRAL.
THE REST OF THIS WEEK WILL BE MUCH COOLER, BELOW AVERAGE IN
FACT, IN THE 70S. THE UPPER PATTERN WILL TURN NORTHWEST
WEDNESDAY, BEFORE TURNING TO THE SOUTHWEST THURSDAY. DAILY
CHANCES OF SHOWERS AND THUNDERSTORMS ARE POSSIBLE, INCLUDING
OVERNIGHT THROUGH SATURDAY MORNING IN THE ACTIVE SOUTHWEST FLOW.
THERE IS CURRENTLY A LEVEL 1 RISK OF SEVERE STORMS AGAIN
WEDNESDAY IN THE SOUTH, WITH CURRENT HAZARDS BEING GOLF BALLS
AND 70MPH WINDS. IT IS POSSIBLE THAT OVER AN INCH OF RAIN COULD
FALL BETWEEN TODAY AND SATURDAY MORNING ACROSS OUR FORECAST
AREA. THURSDAY AND FRIDAY LOOK VERY BREEZY FROM A PRESSURE
GRADIENT, NEAR ADVISORY LEVEL. THIS WEEKEND LOOKS WARMER IN
THE LOWER 80S, THEN MAYBE BACK TO AVERAGE EARLY NEXT WEEK.
AVIATION /18Z TAFS THROUGH 18Z WEDNESDAY/
ISSUED AT 240 PM CDT TUE AUG 11 2026
VFR THROUGH THE PERIOD WITH POSSIBLE THUNDERSTORMS LATE THIS
EVENING THROUGH WEDNESDAY MORNING. STRONG ERRATIC WINDS AND
LARGE HAIL IS POSSIBLE WITH THESE STORMS. A PROB30 WAS USED
UNTIL CONFIDENCE INCREASES.
BIS WATCHES/WARNINGS/ADVISORIES
NONE.
DISCUSSION...SMITH
AVIATION...SMITH
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