798
FXUS63 KBIS 010003
AFDBIS
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BISMARCK ND
703 PM CDT THU JUL 31 2025
KEY MESSAGES
- AREAS OF SMOKE WILL CONTINUE THROUGH AT LEAST FRIDAY AFTERNOON
ACROSS PORTIONS OF WESTERN AND CENTRAL NORTH DAKOTA,
POTENTIALLY LIMITING VISIBILITY AND IMPACTING AIR QUALITY AT
TIMES.
- BELOW AVERAGE TEMPERATURES ARE EXPECTED THROUGH THE WEEKEND,
WITH HIGHS MAINLY IN THE LOWER 70S TO LOWER 80S AND LOWS IN
THE LOWER 50S TO LOWER 60S.
- PERIODIC LOW TO MEDIUM CHANCES OF SHOWERS AND THUNDERSTORMS
(20 TO 60 PERCENT) ARE POSSIBLE THROUGH THE REMAINDER OF THE
WEEK AND INTO EARLY NEXT WEEK.
UPDATE
ISSUED AT 701 PM CDT THU JUL 31 2025
ONLY MINIMAL FORECAST CHANGES WERE NEEDED FOR THIS UPDATE, MAINLY TO
BETTER ALIGN WITH CURRENT OBSERVATIONS AND TRENDS. SOME WEAK
CONVECTION WAS TRYING TO FORM FROM BETWEEN MOTT AND ELGIN TO BETWEEN
HETTINGER AND MCINTOSH, SD A COUPLE HOURS AGO, BUT IT WAS UNABLE TO
SUSTAIN.
DISCUSSION
ISSUED AT 323 PM CDT THU JUL 31 2025
THIS AFTERNOON, RIDGING ALOFT OVER THE NORTHERN ROCKIES
EXTENDED INTO THE CANADIAN PRAIRIES, WITH TROUGHING ACROSS BOTH
THE NORTHEASTERN CONUS AND OFF THE WEST COAST. SURFACE HIGH
PRESSURE WAS CENTERED OVER NORTHERN MINNESOTA, WITH A MODEST
PRESSURE GRADIENT ACROSS WESTERN NORTH DAKOTA LEADING TO BREEZY
SOUTHEAST WINDS. MAIN FORECAST CONCERN THROUGH THE DAY HAS BEEN
NEAR- SURFACE WILDFIRE SMOKE, WHICH HAS KEPT VISIBILITIES IN THE
5 TO 6 MILE RANGE, MOST CONSISTENTLY ACROSS THE EAST AND PARTS
OF THE NORTH CENTRAL. SCATTERED CLOUDS HAVE BEEN PERSISTENT
ACROSS MOST OF THE FORECAST AREA, AND WHERE THERE AREN'T CLOUDS,
SMOKE IS KEEPING SKIES HAZY.
WE ARE CARRYING LOW TO MEDIUM CHANCES FOR SHOWERS AND
THUNDERSTORMS THROUGH THIS AFTERNOON AND TONIGHT ACROSS WESTERN
AND SOUTH CENTRAL NORTH DAKOTA, AS EMBEDDED IMPULSES RIDE
THROUGH THE RIDGE ACROSS MONTANA. MLCAPE IS MARGINAL AT BEST,
GENERALLY UP TO 1000 J/KG (ALTHOUGH HIGHER LOOKING INTO EASTERN
MONTANA), WHILE BULK SHEAR IS LACKING AT ONLY 20 TO MAYBE 30
KNOTS. THE ONLY PARAMETER THAT SPC MESOANALYSIS IS ADVERTISING
AS MODERATELY HIGH IS LOW- LEVEL LAPSE RATES, BUT OTHERWISE THE
ENVIRONMENT IS NOT SUPPORTIVE OF SEVERE THUNDERSTORMS. CAN'T
RULE OUT GETTING A STRONGER STORM WITH INITIAL DEVELOPMENT DUE
TO THE LAPSE RATES AND BIT OF BUOYANCY, BUT THE LACK OF SHEAR
SIGNALS STORMS WON'T BE LONG- LIVED IF THEY DO BECOME STRONG.
THE SLOW STORM MOTION WILL ALSO BE SOMETHING TO WATCH, WITH
POTENTIAL FOR VERY LOCALIZED HIGHER RAIN AMOUNTS. WE ARE ALREADY
SEEING ONE CELL DEVELOP IN EASTERN MONTANA, ALTHOUGH LATEST
CAMS KEEP CONVECTION QUITE LIMITED UNTIL LATER THIS EVENING.
MORE OF THE SAME ON FRIDAY, WITH NEAR-SURFACE SMOKE FOCUSED
ACROSS THE CENTRAL AND EASTERN PARTS OF THE STATE. ALTHOUGH IT
DOESN'T LOOK LIKE TRUE SPLIT FLOW, THERE ARE SOME ENSEMBLE
MEMBERS FAVORING A MORE ZONAL SOUTHERN STREAM ACROSS THE DAKOTAS
THIS WEEKEND, ALLOWING SHORTWAVES TO CROSS THE SUBREGION.
CURRENT BLENDED POPS HAVE THE HIGHEST PROBABILITIES FOR SHOWERS
AND THUNDERSTORMS ACROSS THE SOUTHWEST AND FAR SOUTH CENTRAL
FRIDAY AND FRIDAY NIGHT. THE CHANCE FOR SEVERE WEATHER IS
OVERALL LOW, ALTHOUGH THERE ARE SOME PRETTY LARGE DIFFERENCES
AMONG DETERMINISTIC GUIDANCE REGARDING THE FORECAST AMOUNT OF
0-6KM SHEAR, AND CSU MACHINE LEARNING DOES HAVE LOW
PROBABILITIES FOR SEVERE HAIL EXTENDING ACROSS THE SOUTHWEST AND
SOUTH CENTRAL. HIGH TEMPS ON FRIDAY WILL BE IN THE LOWER 70S TO
LOWER 80S.
THERE ARE WIDESPREAD LOW CHANCES FOR SHOWERS AND THUNDERSTORMS
DURING THE DAY SATURDAY, INCREASING TO A BROAD 35 TO 50 PERCENT
CHANCE SATURDAY NIGHT THROUGH SUNDAY NIGHT. COULD BE SOME
POTENTIAL FOR A FEW STRONGER STORMS ACROSS THE SOUTH ON
SATURDAY, DEPENDING ON THE PLACEMENT OF THE WAVE AND HOW HIGH
BOUYANCY ENDS UP. HIGHS WILL BE IN THE 70S ON SATURDAY AND
SUNDAY.
RIDGING BUILDS AND SHIFTS EAST FOR NEXT WORK WEEK, LEADING TO A
SLIGHT WARMING TREND TO BRING TEMPERATURES BACK CLOSER TO
NORMAL. DAILY CHANCES FOR SHOWERS AND THUNDERSTORMS PERSIST
THROUGH MUCH OF THE WORK WEEK, WITH NSSL AND CSU MACHINE
LEARNING SEVERE WEATHER PROBABILITIES STILL LOW BUT A BIT MORE
WIDESPREAD BY THE MIDDLE OF THE WEEK.
AVIATION /00Z TAFS THROUGH 00Z SATURDAY/
ISSUED AT 701 PM CDT THU JUL 31 2025
NEAR-SURFACE SMOKE WILL CONTINUE TO REDUCE VISIBILITY ACROSS CENTRAL
AND EASTERN NORTH DAKOTA THROUGH THE FORECAST PERIOD, AND AT TIMES
IN WESTERN PARTS OF THE STATE. PREVAILING VISIBILITIES ARE
MOSTLY EXPECTED AROUND 5-7 MILES, BUT SOME PERIODS OF LOWER
VISIBILITY CANNOT BE RULED OUT. MVFR CEILINGS ARE LIKELY TO
DEVELOP ACROSS SOUTHWEST NORTH DAKOTA FRIDAY MORNING, POSSIBLY
LASTING INTO THE AFTERNOON. THERE IS A LOW CHANCE OF SHOWERS AND
THUNDERSTORMS ACROSS MUCH OF WESTERN AND SOUTH CENTRAL NORTH
DAKOTA THROUGHOUT THE FORECAST PERIOD. PROB30 MENTIONS WERE
ADDED WHERE AND WHEN FORECAST CONFIDENCE IS SLIGHTLY ELEVATED.
WINDS WILL REMAIN SOUTHEASTERLY AROUND 10-15 KTS THROUGH THE
FORECAST PERIOD, BECOMING GUSTY FRIDAY AFTERNOON.
BIS WATCHES/WARNINGS/ADVISORIES
NONE.
UPDATE...HOLLAN
DISCUSSION...JONES
AVIATION...HOLLAN
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