537
FXUS63 KBIS 170857
AFDBIS
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BISMARCK ND
357 AM CDT MON AUG 17 2026
KEY MESSAGES
- LOW CHANCES (20-30%) FOR SHOWERS AND THUNDERSTORMS TODAY.
ISOLATED SEVERE STORMS (LEVEL 1 OUT OF 5) ARE POSSIBLE IN THE
SOUTHERN JAMES RIVER VALLEY THIS AFTERNOON.
- LOW TO MEDIUM CHANCES (20-40%) FOR SHOWERS AND ISOLATED
THUNDERSTORMS TONIGHT. SEVERE WEATHER IS NOT EXPECTED.
- LOW TO MEDIUM CHANCES (20-40%) FOR HIT AND MISS SHOWERS AND
THUNDERSTORMS CONTINUE TUESDAY THROUGH WEDNESDAY, THEN ONLY
LOW CHANCES (20%) LATE IN THE WORK WEEK.
- SEASONABLE TEMPERATURES ARE EXPECTED THIS WEEK.
DISCUSSION
ISSUED AT 221 AM CDT MON AUG 17 2026
CURRENTLY, WEAK LOW PRESSURE WAS LOCATED OVER THE AREA, AHEAD OF
AN APPROACHING COLD FRONT DROPPING SOUTH FROM CANADA. SKIES WERE
PARTLY CLOUDY AND LAST NIGHTS EVENING CONVECTION HAS MOSTLY
DISSIPATED EXCEPT FOR AN ISOLATED SHOWER OVER NORTHWEST ND. WE
REMAIN WITHIN A NORTHWEST UPPER LEVEL FLOW. ALTHOUGH MODEST AT
BEST, ELEVATED INSTABILITY REMAINS OVER THE AREA WITH MODEST
SHEAR AS WELL. SHORT TERM GUIDANCE HAS BEEN OVERDOING THE
OVERNIGHT CONVECTION AND CONTINUES SO. MAY TAKE A LOOK AND SEE
HOW THE NORTHWEST CONVECTION IS GOING IN A BIT AND IF NOT MUCH
HAS CHANGED, DROP FROM CHANCE TO SLIGHT CHANCE EARLY THIS
MORNING. WITH THAT SAID, THINK THERE IS A CHANCE OF SHOWERS AND
ISOLATED THUNDERSTORMS YET THIS MORNING, BUT PROBABLY MORE LIKE
MID TO LATE MORNING AS ELEVATED INSTABILITY AND BULK SHEAR ALOFT
CONTINUE TO INCREASE. FORECAST NAM SOUNDINGS FROM DICKINSON TO
BISMARCK AND JAMESTOWN INDICATE 1000-1500 J/KG OF SBCAPE WITH
30-40KTS OF BULK SHEAR AND LITTLE CIN, LATE THIS MORNING, THEN
INSTABILITY DROP PRETTY QUICK THIS AFTERNOON. IF YOU GO DOWN TO
ASHLEY, INSTABILITY INCREASES TO AROUND 2000 J/KG WITH 35 TO 40
KNOTS OF SHEAR LATE MORNING, BEFORE ALSO LOSING INSTABILITY AS
DRIER AIR MOVES IN THIS AFTERNOON. SPC HAS PULLED THE MARGINAL
RISK OF SEVERE STORMS (THAT WAS EAST OF THE FORECAST AREA) BACK
WEST INTO THE FAR SOUTHERN JAMES RIVER VALLEY. THINK THERE IS A
SMALL WINDOW LATE MORNING INTO THE EARLY AFTERNOON FOR A
STRONGER TO POSSIBLY SEVERE STORM HERE. THE MAIN HAZARDS WOULD
BE QUARTER SIZED HAIL AND 60 MPH WINDS.
AFTER EARLY THIS AFTERNOON, THE THREAT FOR SEVERE STORMS LOOKS
TO BE OVER FOR A WHILE. AT THE SURFACE HIGH PRESSURE BUILDS OVER
THE AREA TONIGHT, BUT JET ENERGY OVER THE AREA MAY PROVIDE
ENOUGH FORCING FOR SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS
TONIGHT INTO TUESDAY, WITH ANOTHER WAVE BRINGING LOW CHANCES FOR
SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS ON WEDNESDAY.
SEVERE STORMS ARE NOT EXPECTED AT THIS TIME TUESDAY THROUGH
WEDNESDAY.
UPPER LEVEL RIDGING OVER THE WESTERN U.S WEST AMPLIFIES AND
PUSHES EAST WEDNESDAY THROUGH FRIDAY. NORTHWEST FLOW REMAINS
OVER THE AREA SO A LOW THREAT FOR A HIT OR MISS THUNDERSTORM
WILL REMAIN, BUT OVERALL, PRECIPITATION CHANCES WILL REMAIN LOW
FOR THE SECOND HALF OF THE WORK WEEK.
TEMPERATURES REMAIN SEASONABLE THROUGH THE FORECAST PERIOD.
HIGH TEMPERATURES WILL GENERALLY RANGE FROM THE MID 70S TO MID
80S. A LITTLE COOLER ON TUESDAY AND A LITTLE WARMER ON THURSDAY.
FORECAST LOWS ARE EXPECTED TO RANGE FROM THE MID 40S TO MID
50S. AGAIN, A LITTLE COOLER ON TUESDAY, AND WITH SOME UPPER 50S
TO LOWER 60S LATER IN THE WEEK.
AVIATION /06Z TAFS THROUGH 06Z TUESDAY/
ISSUED AT 1156 PM CDT SUN AUG 16 2026
A WEAK LOW PRESSURE SYSTEM WILL TRACK EAST ACROSS THE FORECAST
AREA BRINGING ISOLATED SHOWERS AND POSSIBLY A THUNDERSTORM LATE
TONIGHT INTO MONDAY MORNING. LIGHT SOUTH WINDS WILL SHIFT
SOUTHWEST 5 TO 10 MPH LATE TONIGHT. A COLD FRONT WILL DROP
SOUTHEAST THROUGH THE AREA TOMORROW. WINDS WILL SHIFT TO THE
NORTHWEST 10 TO 20 MPH BEHIND THE COLD FRONT, WITH A SLIGHT
CHANCE OF A SHOWER OR THUNDERSTORM MAINLY THE SOUTHERN TAF SITES
MONDAY AFTERNOON. CURRENTLY CONVECTION TOO ISOLATED IN NATURE TO
INCLUDE IN ANY TAF, BUT ANY THUNDERSTORMS WOULD PRODUCE LOCALLY
GUSTY AND ERRATIC WINDS AND BRIEF HEAVY DOWNPOURS.
BIS WATCHES/WARNINGS/ADVISORIES
NONE.
DISCUSSION...TWH
AVIATION...TWH
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