671
FXUS63 KBIS 081950
AFDBIS
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BISMARCK ND
250 PM CDT SAT AUG 8 2026
KEY MESSAGES
- VERY LOW HUMIDITY VALUES COMBINED WITH WINDS BECOMING
NORTHERLY AND GUSTY WILL RESULT IN NEAR CRITICAL FIRE WEATHER
CONDITIONS IN WESTERN AND ESPECIALLY SOUTHWESTERN PORTIONS
THROUGH THIS EVENING.
- ISOLATED THUNDERSTORMS POSSIBLE THIS EVENING OVER SOUTH
CENTRAL NORTH DAKOTA INTO THE JAMES RIVER VALLEY. A FEW STORMS COULD
BE SEVERE WITH GOLF BALL SIZE HAIL AND 60 MPH WIND GUSTS
BEING THE MAIN THREATS.
- LOW TO MEDIUM CHANCES (MAINLY 20 TO 50 PERCENT) FOR
PRECIPITATION SUNDAY INTO THE UPCOMING WORK WEEK. ISOLATED
STRONG TO SEVERE THUNDERSTORMS MAY RETURN TO SOUTHERN NORTH
DAKOTA LATE SUNDAY AFTERNOON THROUGH SUNDAY NIGHT.
- ABUNDANT WILDFIRE SMOKE ALOFT EXPECTED TO CONTINUE THROUGH THE
WEEKEND, WITH SOME PATCHY SMOKE AT THE SURFACE DURING THE DAY
AND EVENING HOURS.
DISCUSSION
ISSUED AT 250 PM CDT SAT AUG 8 2026
INVERTED SURFACE TROUGH WILL PUSH EASTWARD ACROSS THE SOUTHERN
HALF OF THE STATE TONIGHT. MEANWHILE A WEAK BACKDOOR FRONT WILL
PUSH ACROSS THE NORTH DURING THE SAME TIME, POSSIBLY INFLUENCING
THE SURFACE TROUGH AND ASSOCIATED WARM FRONT. TO START, AS THE
TROUGH MOVES EAST, INCREASED NORTHERLY WINDS WILL BE FOUND WITH
SOME VERY LOW RH VALUES IN THE TEENS ACROSS WESTERN PORTIONS. A
COUPLE HOURS OF NEAR CRITICAL FIRE WEATHER CONDITIONS ARE
POSSIBLE AS A RESULT THROUGH THIS EVENING, ESPECIALLY IN
SOUTHWESTERN PORTIONS. THIS FEATURE WILL MEET ABUNDANT CAPE AND
SHEAR IN SOUTH CENTRAL AND SOUTHEASTERN PORTIONS THIS EVENING,
WITH A SHEAR VECTOR FAVORING DISCRETE SUPERCELLS. THERE ARE
BRIEF PERIODS THE SURFACE AND MIX LAYERS ARE LIMITEDLY CAPPED,
ALTHOUGH FOR THE MOST PART MUCH OF THE INSTABILITY IS ELEVATED.
THERE IS ALSO A BRIEF PERIOD WHERE HODOGRAPHS WOULD SUPPORT
ROTATING SUPERCELLS VS SPLITTING CELLS WITH WEAK ROTATION. THUS
THERE REMAINS A CONDITIONAL RISK FOR ISOLATED SEVERE STORMS
THROUGH THIS EVENING. MAIN HAZARDS WILL BE HAIL TO GOLF BALL
SIZE GIVEN THE POSSIBILITY FOR DISCRETE CELLS COMBINED WITH
MODEST TO HIGH CAPE AND SHEAR, ALONG WITH WINDS TO 60 MPH. LCLS
LOOK TOO HIGH FOR A TORNADO THREAT DESPITE SOME LOW STP NUMBERS
THIS EVENING. THUNDERSTORMS WILL LIKELY NOT BE SURFACE BASED
WHICH ALSO LIMITS THE TORNADO THREAT THIS EVENING. THE MENTIONED
BACKDOOR FRONT SHOULD PUSH THE THUNDERSTORM ACTIVITY INTO SD
TONIGHT, ALTHOUGH LINGERING INSTABILITY WILL BRING ISOLATED
THUNDERSTORM CHANCES THROUGH THE NIGHT ACROSS THE SOUTHEAST.
LOWS TONIGHT WILL BE IN THE 50S. THERE ARE SOME IMPROVED RH
RECOVERIES TONIGHT, ALTHOUGH A STEADY NORTHEAST WIND SHOULD
LIMIT FOG FORMATION. ABUNDANT WILDFIRE SMOKE ALOFT WILL ALSO BE
FOUND THROUGH TONIGHT AND AGAIN ON SUNDAY. PATCHY SMOKE MAY MIX
TO THE SURFACE THROUGH THIS EVENING AND AGAIN SUNDAY THROUGH
SUNDAY EVENING.
SURFACE HIGH LINGERS ACROSS THE STATE SUNDAY MORNING, THEN GETS
NUDGE SLIGHTLY NORTHWARD. THE STALLED BOUNDARY TO OUR SOUTH ALSO
GETS NUDGE SLIGHTLY NORTHWARD AND TURNS INTO A WEAK WARM FRONT.
BY LATE SUNDAY AFTERNOON AND ESPECIALLY THROUGH SUNDAY NIGHT
MODEST CAPE AND SHEAR RETURN ALONG THIS BOUNDARY, WITH PERHAPS
ADDITIONAL HELP BY A MID LEVEL WAVE IN NORTHWEST FLOW. THIS
COULD BRING ANOTHER ROUND OF ISOLATED TO PERHAPS SCATTERED
SHOWERS AND THUNDERSTORMS. SPC HAS RETURNED AND EXPANDED A
MARGINAL RISK TO MUCH OF SOUTHERN ND FOR SUNDAY THROUGH SUNDAY
NIGHT. HAZARDS WILL BE SIMILAR TO TONIGHTS, WITH GOLF BALL SIZED
HAIL AND WINDS TO 60 MPH. STORM MODE MAY START OUT DISCRETE
THEN GO TO MORE OF A LINEAR MODE AS STORMS PROGRESS ALONG THE
BOUNDARY SUNDAY NIGHT. OTHERWISE LOOK FOR MORE SEASONABLE
TEMPERATURES SUNDAY AND SUNDAY NIGHT WITH A STEADY EAST WIND.
INCREASED HUMIDITY VALUES FROM SLIGHTLY COOLER TEMPERATURES
SHOULD ALSO IMPROVE THE FIRE WEATHER CONCERNS FOR SUNDAY.
ZONAL FLOW PATTERN WILL KEEP TEMPERATURES NEAR NORMAL TO START
NEXT WEEK. DISTURBANCES WITHIN THIS WESTERLY FLOW COULD ALSO
PROVIDE NEAR DAILY CHANCES FOR SHOWERS AND THUNDERSTORMS. THE
UNSTABLE BOUNDARY FOUND THIS WEEKEND COULD LINGER AS WELL
PERHAPS BRINGING ISOLATED STRONG TO SEVERE THUNDERSTORMS. SPC
HAS CLIPPED SOME SOUTH CENTRAL PORTIONS WITH A MARGINAL RISK ON
MONDAY AS A RESULT. CSU-MLP ALSO SHOWING THIS SIGNAL FOR MONDAY
AND AGAIN ON TUESDAY. OF NOTE IS WPC HAVING A MARGINAL RISK FOR
EXCESSIVE RAINFALL IN SOUTHERN AND SOME WESTERN AREAS MONDAY
THROUGH WEDNESDAY, WITH THE MOST WIDESPREAD COVERAGE ON TUESDAY.
PWATS ARE SLIGHTLY INCREASED ON THESE DAYS AND WILL ALSO DEPEND
ON THE AMOUNT OF THUNDERSTORMS THAT CAN DEVELOP IN ONE AREA
ALONG THIS BOUNDARY. CLUSTERS THEN INDICATE EITHER A CONTINUED
ZONAL FLOW PATTERN OR PERHAPS A SHIFT TO A WEAK BROAD TROUGH
PATTERN COULD RETURN MID TO LATE WEEK. THIS COULD RESULT IN
FURTHER COOLING OF TEMPERATURES, WITH CONTINUED NEAR DAILY
CHANCES FOR SHOWERS AND THUNDERSTORMS.
AVIATION /18Z TAFS THROUGH 18Z SUNDAY/
ISSUED AT 1232 PM CDT SAT AUG 8 2026
GENERALLY VFR CONDITIONS ARE EXPECTED THROUGH THE FORECAST
PERIOD. WILDFIRE SMOKE ALOFT COULD MIX TO THE SURFACE AND
PERHAPS BRING SOME MVFR VISIBILITY, ESPECIALLY IN SOUTHWEST AND
SOUTH CENTRAL PORTIONS THIS AFTERNOON AND EVENING. OVER PARTS OF
FAR SOUTH CENTRAL NORTH DAKOTA INTO THE JAMES RIVER VALLEY,
ISOLATED TO WILDLY SCATTERED THUNDERSTORMS WILL BE POSSIBLE THIS
EVENING. CONFIDENCE WAS ONLY HIGH ENOUGH TO INCLUDE A PROB30
GROUP IN THE KJMS TAF. OTHERWISE LOOK FOR DRY AND VFR CONDITIONS
TONIGHT INTO SUNDAY MORNING, WITH SMOKE LINGERING ALOFT. WINDS
WILL SHIFT TO AN EAST NORTHEAST WIND THROUGHOUT THE FORECAST
PERIOD.
BIS WATCHES/WARNINGS/ADVISORIES
NONE.
DISCUSSION...ANGLIN
AVIATION...ANGLIN
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