383
FXUS63 KBIS 092026
AFDBIS
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BISMARCK ND
326 PM CDT SAT MAY 9 2026
KEY MESSAGES
- CRITICAL FIRE WEATHER CONDITIONS CONTINUE NORTHWEST AND NORTH
CENTRAL NORTH DAKOTA WITH NEAR-CRITICAL CONDITIONS ELSEWHERE.
- FRIGID LOW TEMPERATURES TONIGHT, THUS FREEZE WARNINGS AND
FROST ADVISORIES ARE IN EFFECT THROUGH EARLY SUNDAY MORNING.
- DAILY WINDY CONDITIONS AND LOW HUMIDITY VALUES THROUGH THE
UPCOMING WORK WEEK MAY LEAD TO DAILY CRITICAL FIRE WEATHER
CONDITIONS FOR PARTS OF THE AREA.
DISCUSSION
ISSUED AT 156 PM CDT SAT MAY 9 2026
CURRENT SURFACE ANALYSIS PLACES LOW OVER SOUTHEAST ONTARIO WITH
HIGH SETTLING THROUGH SASKATCHEWAN INTO EASTERN MONTANA. UPPER
LEVEL ANALYSIS PLACES LOW OVER NORTHERN ONTARIO, WITH RIDGE
OVER THE WESTERN CONUS. SLIGHTLY CYCLONIC NORTH-NORTHWESTERLY
FLOW REMAINS OVER OUR AREA RESULTING IN SOME CLOUD DEVELOPMENT
OVER OUR EASTERN AREAS. OTHERWISE, DRY CONDITIONS CONTINUE WITH
TEMPERATURES ABOUT 5 TO 10 DEGREES BELOW AVERAGE.
FOR THE REST OF TODAY INTO TONIGHT, DRY CONDITIONS REMAIN
RESULTING IN HUMIDITY VALUES DIPPING INTO THE MID TEENS TO MID
20S OVER MOST OF THE AREA, WITH THE OVERLAP OF THE HIGHER WINDS
WITH THE LOWEST HUMIDITY VALUES REMAINING OVER PARTS OF
NORTHWEST/NORTH CENTRAL NORTH DAKOTA WHERE A RED FLAG WARNING
REMAINS IN PLACE. SEE FIRE WEATHER DISCUSSION BELOW FOR MORE
DETAILS. AS WE GET INTO TONIGHT WINDS WILL DIMINISH AS
AFOREMENTIONED SURFACE HIGH PUSHES OVER. WITH THE DRY
ATMOSPHERE IN PLACES, MAINLY CLEAR SKIES, AND LIGHT WINDS,
EXPECT TEMPERATURES TO DROP BELOW NBM GUIDANCE. MOST LOCATIONS
SHOULD DIP INTO THE MID 20S TO LOWER 30S, BUT SOME CLOUDS
LOITERING OVER THE SOUTHWEST MAY KEEP THAT AREA A BIT WARMER.
THEREFORE, HAVE ISSUED A FREEZE WARNING FOR ALL AREAS EXCEPT
PARTS OF THE SOUTHWEST WHERE A FROST ADVISORY IS IN PLACE.
ON SUNDAY, HIGH PRESSURE MEANDERS TO THE EAST KEEPING WINDS
GENERALLY LIGHT OVER THE AREA. TEMPERATURES WARM A BIT BEHIND
THE HIGH AS UPPER RIDGE NUDGES INTO THE NORTHERN PLAINS.
THEREFORE, HIGHS WILL PUSH ABOVE AVERAGE OVER THE WEST, BUT
STILL MAY STAY A BIT ON THE COOLER SIDE OVER OUR EASTERN
LOCATIONS. SURFACE TROUGH DEEPENS TO THE LEE OF THE
CANADIAN/NORTHERN ROCKIES OVERNIGHT AS SURFACE HIGH PUSHES
EAST. THIS WILL ALLOW SOUTHERLY WINDS TO START INCREASING
OVERNIGHT.
MONDAY WILL SEE AFOREMENTIONED LEE SIDE TROUGH CLOSE OFF AND
MOVE EASTERLY THROUGH THE SOUTHERN PRAIRIE PROVINCES, AS A
POTENT SHORT WAVE TROUGH BUSTS THROUGH THE RIDGE INTO THE
NORTHERN PLAINS. SOUTHERLY WINDS WILL BE ON THE INCREASE
BRINGING A VERY WARM DAY TO PARTS OF THE AREA, WITH HIGHS IN THE
80S OVER OUR WEST. SURFACE TROUGH FOLLOWED BY A COLD FRONT
SLIDE THROUGH WITH THE PASSING LOW, WITH WINDS SHIFTING WEST
THEN NORTHWEST AND REMAINING GUSTY. THIS WILL COMBINE WITH A DRY
LOWER ATMOSPHERE TO CAUSE ANOTHER DAY OF FIRE WEATHER PROBLEMS,
ESPECIALLY OVER THE WEST (AGAIN SEE FIRE DISCUSSION BELOW). TO
THE EAST, HUMIDITY MAY BE A BIT HIGHER DEPENDING ON TIMING OF
THE AFOREMENTIONED SYSTEM. GUIDANCE IS SUGGESTING AN AREA OF
INSTABILITY DEVELOPING. ALTHOUGH THIS MAY ONLY BE CAPE VALUES OF
200-500 J/KG, QUITE HIGH FORECAST DEEP LAYER SHEAR (50-60 KTS
EFFECTIVE BULK) IS NOTED, THUS THE POTENTIAL FOR A DAMAGING
WIND THREAT. THEREFORE HAVE PAINTED IN LOW THUNDERSTORM CHANCES
IN THE AFTERNOON/EVENING HOURS OVER PARTS OF OUR EAST.
ON TUESDAY HIGHLIGHT WILL BE THE POTENTIAL FOR HIGHER WINDS
OVER EASTERN PORTIONS OF OUR AREA IN THE WAKE OF THE
AFOREMENTIONED COLD FRONT. WITH THAT SAID, THE AIRMASS BEHIND
THE COLD FRONT WILL ACTUALLY BE QUITE MILD, SO EXPECT HIGHS TO
PUSH INTO THE UPPER 60S TO MID 70S.
WARM AND DRY CONDITIONS CONTINUE THROUGH AT LEAST MID-WEEK.
TOWARDS THE END OF THE WEEK A FEW DISTURBANCES MIGHT MOVE
THROUGH, BUT GUIDANCE REMAINS LEAN WITH PRODUCING PRECIPITATION
WITH THIS. TEMPERATURES REMAIN MILD, WITH EVEN THE NBM 25TH
PERCENTILE OF TEMPERATURE SPREADS REMAIN NOTABLY ABOVE
AVERAGE THROUGH SATURDAY.
AVIATION /12Z TAFS THROUGH 12Z SUNDAY/
ISSUED AT 1150 AM CDT SAT MAY 9 2026
VFR CONDITIONS WILL PREVAIL THROUGH THE FORECAST PERIOD.
FIRE WEATHER
ISSUED AT 525 AM CDT SAT MAY 9 2026
CRITICAL FIRE WEATHER CONDITIONS WILL CONTINUE THIS AFTERNOON
INTO THIS EVENING, MAINLY ALONG AND NORTH OF HIGHWAY 2 AND ALONG
AND WEST OF HIGHWAY 83. WINDS WILL BE NORTHWEST AROUND 20 MPH WITH
GUSTS NEAR 30 MPH, WHILE MINIMUM RELATIVE HUMIDITY VALUES DROP AS
LOW AS 15 PERCENT. NEAR CRITICAL FIRE WEATHER CONDITIONS WILL
CONTINUE ELSEWHERE WITH MINIMUM HUMIDITY VALUES IN THE MID TEENS
TO MID 20S.
FIRE WEATHER CONCERNS ARE RELATIVELY LOWEST ON SUNDAY, WITH
FORECAST MINIMUM RH AROUND 20 TO 30 PERCENT AND AFTERNOON WINDS
RANGING FROM NORTHERLY AROUND 10 MPH IN THE JAMES RIVER VALLEY
TO VARIABLE AROUND 5 MPH OR LESS ACROSS THE REST OF WESTERN AND
CENTRAL NORTH DAKOTA.
THE MOST CONCERNING PERIOD FOR FIRE WEATHER THIS COMING WEEK IS
MONDAY THROUGH TUESDAY. BY MIDDAY MONDAY, SOUTHERLY WINDS ARE
FORECAST TO INCREASE TO AROUND 20 TO 30 MPH, STRONGEST BETWEEN
THE MISSOURI AND JAMES RIVER VALLEYS WHERE GUSTS COULD APPROACH
45 MPH. EVEN THOUGH SOUTHERLY WINDS WILL BE RELATIVELY LIGHTER
IN WESTERN NORTH DAKOTA TO START THE DAY, A COLD FRONT IS
SCHEDULED TO ARRIVE FROM THE WEST BY MID AFTERNOON. THIS COLD
FRONT WILL SHIFT WINDS TO THE NORTHWEST AND COULD INCREASE
SPEEDS AS HIGH AS 30 MPH, WITH GUSTS TO 45 MPH. THIS WIND SHIFT
COULD OCCUR CLOSE TO THE TIMING OF LOWEST DIURNAL HUMIDITY,
WHICH COULD BE UNDER 20 PERCENT IN SOME AREAS. THERE IS HIGH
CONFIDENCE IN MINIMUM RH AROUND 20 PERCENT WEST TO 30 PERCENT
CENTRAL ON MONDAY. BUT EVEN WITH THE SLIGHTLY HIGHER RH IN
CENTRAL NORTH DAKOTA, THE SOUTHERLY WINDS COULD STILL BE STRONG
ENOUGH TO APPROACH CRITICAL FIRE WEATHER CONDITIONS.
THE COLD FRONT WILL CONTINUE TO PROGRESS EASTWARD ACROSS THE
STATE MONDAY EVENING, SHIFTING WINDS TO THE NORTHWEST. THE
STRENGTH OF GUSTS TRAILING THE FRONT BECOMES LESS CERTAIN WITH
THE LOSS OF DIURNAL HEATING, BUT DETERMINISTIC GUIDANCE DOES
SHOW MODEST VALUES OF COLD AIR ADVECTION AND PRESSURE RISES
PAIRED WITH AN INCREASING LOW LEVEL WRAP-AROUND JET. ENSEMBLES
CONTINUE TO TREND WINDIER FOR TUESDAY, WITH BROAD MEDIUM CHANCES
FOR NORTHWEST WINDS GUSTING IN EXCESS OF 50 MPH ACROSS THE
EASTERN HALF OF THE STATE. THE SUSTAINED WINDS OF 35 TO 40 MPH
PROJECTED BY THE LATEST ITERATION OF THE NBM MAY BE TOO HIGH,
BUT STILL RESEMBLE A REASONABLE WORST-CASE SCENARIO. THE MINIMUM
HUMIDITY FORECAST FOR TUESDAY IS AROUND 20 PERCENT FOR THE
WESTERN HALF OF THE STATE, WITH EVEN LOWER POCKETS IN THE FAR
WEST. FROM THE TURTLE MOUNTAINS THROUGH THE NORTHERN JAMES RIVER
VALLEY, MINIMUM RH IS CLOSER TO 30 PERCENT. EVEN THOUGH THE
STRONGEST WINDS MAY NOT OVERLAP WITH THE LOWEST RH ON TUESDAY,
THERE IS STILL POTENTIAL FOR CRITICAL FIRE WEATHER CONDITIONS
ACROSS ALL OF WESTERN AND CENTRAL NORTH DAKOTA. AREAS OF
GREATEST CONCERN ON TUESDAY INCLUDE NORTHWEST PARTS OF THE
STATE ALONG AND NORTH OF THE MISSOURI RIVER, ALL OF CENTRAL
NORTH DAKOTA, AND ESPECIALLY AREAS FROM EAST OF LAKE OAHE TO
THE SOUTHERN JAMES RIVER VALLEY WHERE A STRONGER WIND OUTCOME
COULD PLACE THE ENTIRE AFTERNOON AND EARLY EVENING IN NON-STOP
CRITICAL CONDITIONS.
ON WEDNESDAY, LATEST FORECAST GUIDANCE PLACES THE HIGHEST FIRE
WEATHER CONCERNS BACK OVER WESTERN NORTH DAKOTA, WITH SOUTHERLY
WINDS PROJECTED TO INCREASE TO AROUND 25 MPH AND MINIMUM RH
AROUND 20 PERCENT. FORECAST DETAILS BECOME LESS CERTAIN TO END
THE WEEK, BUT EVERY DAY THROUGH AT LEAST SATURDAY HAS A
POTENTIAL FOR WARM TEMPERATURES, LOW RH, AND GUSTY WINDS.
BIS WATCHES/WARNINGS/ADVISORIES
RED FLAG WARNING UNTIL 9 PM CDT THIS EVENING FOR NDZ001>003-
009>011.
FREEZE WARNING FROM 1 AM CDT /MIDNIGHT MDT/ TO 9 AM CDT /8 AM
MDT/ SUNDAY FOR NDZ001>005-009-010-012-013-017>020-022-023-025-
033-035>037-046>048-050-051-055>060.
FROST ADVISORY FROM 1 AM CDT /MIDNIGHT MDT/ TO 9 AM CDT /8 AM
MDT/ SUNDAY FOR NDZ031-032-040>044-061-062.
DISCUSSION...JJS
AVIATION...JJS
FIRE WEATHER...HOLLAN/JJS
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