980
FXUS63 KBIS 261957
AFDBIS
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BISMARCK ND
257 PM CDT SAT JUL 26 2025
KEY MESSAGES
- HOT AND HUMID THIS AFTERNOON AND EARLY EVENING, WITH
AFTERNOON HEAT INDICES AROUND 100 IN SOUTH CENTRAL NORTH
DAKOTA AND THE JAMES RIVER VALLEY.
- ISOLATED TO SCATTERED SEVERE THUNDERSTORMS ARE ONCE AGAIN
POSSIBLE ACROSS WESTERN AND CENTRAL NORTH DAKOTA TONIGHT.
EXPECTED HAZARDS INCLUDE HAIL UP TO THE SIZE OF GOLF BALLS AND
WIND GUSTS UP TO 70 MPH.
- PERIODIC SHOWERS AND THUNDERSTORMS ARE EXPECTED TO CONTINUE
SUNDAY THROUGH THE FIRST HALF OF NEXT WEEK. ISOLATED SEVERE
THUNDERSTORMS ARE POSSIBLE OVER THIS TIME PERIOD.
- TEMPERATURES EXPECTED TO FALL BELOW AVERAGE BY THE MIDDLE OF
NEXT WEEK.
DISCUSSION
ISSUED AT 148 PM CDT SAT JUL 26 2025
CURRENTLY, IT WAS MOSTLY SUNNY ACROSS MUCH OF WESTERN AND
CENTRAL ND. SCATTERED THUNDERSTORMS CONTINUED ALONG THE
INTERNATIONAL BORDER AND ALSO IN THE SOUTHERN JAMES RIVER
VALLEY. THIS ACTIVITY MAY LINGER ALONG THE BORDERS, BUT IS NOT
EXPECTED TO BE SEVERE. OTHERWISE DRY THROUGH THE REST OF THE
AFTERNOON. HEAT INDICES WERE CURRENTLY IN THE 90S ACROSS THE
SOUTH CENTRAL AND INTO THE JAMES RIVER VALLEY. STILL A WAYS TO
GO FOR REACHING HIGHS. WILL CONTINUE THE HEAT ADVISORY.
THE MAIN FORECAST ISSUE FOR TONIGHT WILL BE THUNDERSTORMS.
CURRENTLY, THERE LOOKS TO BE A WEAK IMPULSE TRACKING THROUGH
CENTRAL ND. THE FAR NORTH MAY BE UNDER THE INFLUENCE OF THE
RIGHT ENTRANCE REGION OF AN UPPER JET OVER SOUTHERN CANADA.
OTHERWISE IT LOOKS LIKE BUILDING UPPER HEIGHTS AND LITTLE IN THE
WAY OF ANY FORCING MECHANISM TODAY. IT WILL BE, HOWEVER, QUITE
UNSTABLE THIS AFTERNOON. MLCAPES ARE ALREADY IN THE 1500-3000
J/KG ACROSS THE FORECAST AREA. FORECAST SOUNDINGS DO SHOW A BIT
OF DRY AIR IN THE LOWER LEVELS AND CURRENT CINS ARE RATHER
STOUT. EFFECTIVE SHEAR HAS BEEN INCREASING THROUGH THE DAY AND
CURRENTLY RANGES FROM 30-35KT SOUTH TO 45 KTS NORTHWEST.
NEEDLESS TO SAY, IF WE COULD SEE SOME CONVECTION TODAY IT WOULD
LIKELY BECOME SEVERE QUICKLY BUT IT'S HIGHLY CONDITIONAL UPON IF
WE CAN OVERCOME THE NEGATIVE EFFECTS OF THE LOWER LEVEL CAPPING
AND UPPER LEVEL RIDGING.
LATER ON, MOST LIKELY NOT UNTIL TONIGHT, WE DO SEE A STRONGER
IMPULSE LIFTING FROM NORTHERN COLORADO INTO EASTERN WYOMING.
THIS WILL LIKELY PROVIDE THE FORCING FOR ASCENT NEEDED TO
INITIATE CONVECTION TONIGHT. THERE MAY ALSO BE ANOTHER WAVE
OVER EASTERN IDAHO WHICH COULD AID IN CONVECTION OVER NORTHERN
WY AND SOUTHEAST MT. CONVECTION IS ALREADY FIRING OFF THE
BIGHORNS AND SOUTHWARD THROUGH EASTERN WYOMING. CAMS HAVE BEEN
PRETTY CONSISTENT IN LIFTING CONVECTION SOUTHWEST TO NORTHEAST
ACROSS THE FORECAST AREA THIS EVENING AND INTO THE EARLY
OVERNIGHT HOURS. THE MAIN THREAT APPEARS TO BE WINDS. WITH DCAPE
WELL IN EXCESS OF 1000 J/KG ACROSS THE SOUTHERN TWO THIRDS OF
THE FORECAST AREA AND A STRONG WAVE LIFTING INTO THE LOCAL AREA,
OUR CURRENTLY POSTED WINDS HAZARDS OF 70 MPH LOOK REASONABLE
FOR NOW. IF THERE WERE TO BE AN EARLY EVENING THUNDERSTORM IT'S
POSSIBLE WE COULD SEE A PERIOD OF LARGE HAIL TO GOLF BALL SIZE,
BUT ONCE WE GET INTO THE MID-EVENING HOURS, WINDS LOOK TO BE THE
MAIN THREAT.
ON SUNDAY SPC HAS PARED BACK THE MARGINAL THREAT OVER THE
EASTERN PORTION OF THE CWA, KEEPING ONLY THE FAR NORTH CENTRAL
IN THE MARGINAL RISK FOR SEVERE STORMS. NOT QUITE SURE ABOUT
THIS. COLD FRONT LOOKS TO DROP SOUTH THROUGH THE AREA BUT WE
REMAIN PRETTY WARM AND THERE LOOKS TO BE SOME PRETTY GOOD SPEED
SHEAR NORTH OF THE BOUNDARY. THERE IS SOME RATHER STRONG MID
LEVEL HEIGHT RISES, WHICH WOULD BE A LIMITING FACTOR FOR
CONVECTION. WE'LL SEE HOW THINGS PLAY OUT AND OVERALL PROBABLY
OKAY LEAVING JUST GENERAL THUNDER FOR MUCH OF THE FORECAST AREA.
THE SEVERE THREAT ON MONDAY REMAINS MARGINAL ACROSS THE FAR
SOUTH AND WE ACTUALLY SEE SOME HEIGHT FALLS TRAVERSE THE
FORECAST AREA. HOWEVER THERE MAY ALSO BE SOME CAPPING ISSUES
MONDAY AS WELL.
WE FINALLY BEGIN TO COOL OFF WITH DIMINISHING THUNDERSTORM
CHANCES AS WE HEAD INTO MID WEEK.
AVIATION /18Z TAFS THROUGH 18Z SUNDAY/
ISSUED AT 1227 PM CDT SAT JUL 26 2025
VFR CONDITIONS TO BEGIN THE 18Z TAF PERIOD. ISOLATED
SHOWER/THUNDERSHOWER ACTIVITY FAR NORTH AND FAR SOUTH THIS
AFTERNOON. LATER TONIGHT WIDESPREAD SHOWERS AND THUNDERSTORMS
ARE EXPECTED TO DEVELOP AND OR MOVE INTO SOUTHERN NORTH DAKOTA
AND MOVE NORTHEAST THROUGH THE NIGHT. ERRATIC AND STRONG WIND
GUSTS, HAIL, AND BRIEF PERIODS OF IFR/LIFR VISIBILITY
RESTRICTIONS FROM HEAVY RAIN ARE POSSIBLE WITH THE STRONGEST
STORMS. OUTSIDE OF THUNDERSTORMS, VFR CONDITIONS AND LIGHT WINDS
ARE EXPECTED.
BIS WATCHES/WARNINGS/ADVISORIES
HEAT ADVISORY UNTIL 8 PM CDT /7 PM MDT/ THIS EVENING FOR
NDZ023-025-034>037-042-045>048-050-051.
DISCUSSION...TWH
AVIATION...TWH
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