509
FXUS63 KBIS 011455
AFDBIS
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BISMARCK ND
955 AM CDT SAT AUG 1 2026
KEY MESSAGES
- VERY HOT THIS WEEKEND, WITH HIGH TEMPERATURES AROUND 100 IN
SOUTHWEST NORTH DAKOTA TODAY AND SOUTH CENTRAL NORTH DAKOTA
ON SUNDAY.
- WINDY SUNDAY AND MONDAY, WITH NEAR-CRITICAL FIRE WEATHER
CONDITIONS EXPECTED ACROSS MUCH OF THE WESTERN HALF OF THE
STATE.
- THE FIRST HALF OF THE UPCOMING WORK WEEK SHOULD BE MUCH
COOLER, WITH HIGHS IN THE 70S AND 80S.
- LOW TO MEDIUM CHANCES FOR SHOWERS AND THUNDERSTORMS LATE
SUNDAY NIGHT THROUGH MONDAY AFTERNOON. A FEW STORMS COULD BE
SEVERE IN CENTRAL AND EASTERN PARTS OF THE STATE.
UPDATE
ISSUED AT 955 AM CDT SAT AUG 1 2026
LITTLE NEEDING UPDATING THIS MORNING. RGB GEOCOLOR SATELLITE
IMAGERY SHOWING SOME SMOKE ALOFT, ALTHOUGH SURFACE OBSERVATIONS
HAVE NOT REPORTED IN RESTRICTIONS YET. OTHERWISE EXPECT HOTTER
TEMPERATURES TODAY ALONG WITH MAINLY DRY CONDITIONS. OVERALL THE
FORECAST REMAINS ON TRACK.
UPDATE
ISSUED AT 646 AM CDT SAT AUG 1 2026
PATCHY SHALLOW FOG HAS DEVELOPED IN THE JAMES RIVER VALLEY. THE
FOG SHOULD NOT LAST BEYOND 8-9 AM CDT AND SHOULD REMAIN LIMITED
TO LOW-LYING AREAS. FARTHER NORTH, SCATTERED LIGHT SHOWERS
CONTINUE TO STREAM OVER THE TURTLE MOUNTAINS EARLY THIS MORNING.
THIS ACTIVITY SHOULD DISSIPATE OR SHIFT OFF TO THE EAST BY
AROUND 8 AM CDT. OTHER THAN THESE TWO FEATURES, AN UNEVENTFUL
AND SUNNY BUT HOT DAY IS EXPECTED, WITH INCREASING SOUTHERLY
WINDS IN CENTRAL NORTH DAKOTA.
DISCUSSION
ISSUED AT 430 AM CDT SAT AUG 1 2026
ANTICYCLONIC NORTHWEST FLOW LIES OVER THE NORTHERN PLAINS EARLY
THIS MORNING, WITH A TRADITIONAL RIDGE AXIS FROM THE GREAT SALT
LAKE TO ALONG THE ALBERTA/SASKATCHEWAN BORDER AND AN EAST-
NORTHEAST POINTING AXIS FROM SOUTHERN NORTH DAKOTA TO LAKE
SUPERIOR. THERE IS A 700 MB SHORTWAVE TRAVERSING SOUTHERN
SASKATCHEWAN UNDERNEATH THE BROAD UPPER RIDGE, WITH LOW LEVEL
JET INDUCED WARM AIR ADVECTION IN SOUTHEAST SASKATCHEWAN AND
SOUTHWEST MANITOBA. THIS HAS INITIATED A SMALL CLUSTER OF
SHOWERS AND THUNDERSTORMS THAT HAS CROSSED INTO FAR NORTH
CENTRAL NORTH DAKOTA AS OF 4 AM CDT. CONFIDENCE ON MAINTENANCE
OF THIS CONVECTION REMAINS LOW, AS FORCING IS FORECAST TO WEAKEN
AND DOWNSTREAM MUCAPE IS ANALYZED TO BE ONLY 100-200 J/KG.
AFTER THIS ACTIVITY DISSIPATES OR DEPARTS TO THE EAST, QUIET
WEATHER IS EXPECTED TO PREVAIL THROUGH THE REST OF THE DAY, WITH
INCREASING SOUTHERLY RETURN FLOW OVER CENTRAL NORTH DAKOTA
BETWEEN A DOWNSTREAM SURFACE RIDGE AND UPSTREAM LEE TROUGHING.
TEMPERATURES ARE PROJECTED TO REACH AROUND 100 DEGREES IN
SOUTHWEST PARTS OF THE STATE THIS AFTERNOON, WITH 90S NORTHWEST
AND CENTRAL AND MID TO UPPER 80S FROM THE TURTLE MOUNTAINS
THROUGH THE JAMES RIVER VALLEY. DEWPOINTS IN THE MID 40 TO MID
50S SHOULD KEEP HEAT INDICES BELOW 100 IN SOUTHWEST NORTH DAKOTA
THIS AFTERNOON, AND THE PROBABILITY OF WIDESPREAD TEMPERATURES
AT OR ABOVE 100 IS NOT HIGH ENOUGH TO ISSUE A HEAT ADVISORY. BUT
IT WILL STILL BE A VERY HOT DAY, AND PRECAUTIONS SHOULD STILL
BE TAKEN TO AVOID OVER-EXPOSURE TO THE HEAT. VERY FEW, IF ANY
CLOUDS ARE EXPECTED TODAY, BUT SMOKE ALOFT COULD PRODUCE A HAZY
SKY.
FROM THIS EVENING INTO SUNDAY MORNING, THE MAIN UPPER RIDGE
AXIS WILL BE TILTED IN A POSITIVE DIRECTION AS A WELL-ADVERTISED
UPPER LOW CROSSES THE CANADIAN ROCKIES. AN OVERNIGHT SOUTHERLY
BREEZE AROUND 10 TO 15 MPH SHOULD KEEP LOW TEMPERATURES IN THE
60S TO LOWER 70S. SOUTHERLY WINDS WILL THEN STRENGTHEN OVER
CENTRAL NORTH DAKOTA BY SUNDAY AFTERNOON, AND MAY APPROACH
ADVISORY CRITERIA OF SUSTAINED WINDS NEAR 30 MPH AND GUSTS NEAR
45 MPH. THIS WILL TAKE PLACE AHEAD OF A COLD FRONT BEING DRIVEN
IN BY THE CANADIAN LOW. BY MID AFTERNOON, THE COLD FRONT IS
PROJECTED TO BE ROUGHLY LOCATED FROM THE TURTLE MOUNTAINS TO
STANDING ROCK RESERVATION. HIGH TEMPERATURES ALONG THE FRONTAL
INTERFACE IN THE SOUTHERN HALF OF THE STATE COULD EASILY REACH
100 DEGREES, AND FEW LOCATIONS COULD APPROACH 105 ON ACCOUNT OF
COMPRESSIONAL HEATING. MOISTURE RETURN IN THE DOWNSTREAM
SOUTHERLY FLOW COULD BRING MID 50S TO MID 60S DEWPOINTS BACK
INTO CENTRAL NORTH DAKOTA, WHICH INTRODUCES A HIGHER PROBABILITY
OF HEAT INDICES REACHING 100 SUNDAY AFTERNOON. THE LATEST NBM
GUIDANCE HIGHLIGHTS THIS IN A CORRIDOR FROM BISMARCK THROUGH
EASTERN GRANT AND WESTERN SIOUX COUNTIES, AND THE MAXIMUM WET-
BULB GLOBE TEMPERATURE RISK ALSO REACHES THE EXTREME CATEGORY IN
THIS AREA. ELSEWHERE ON SUNDAY, EXPECTING HIGHS IN THE 90S
SURROUNDING THE AFOREMENTIONED CORRIDOR, WITH MID TO UPPER 80S
IN BOTH THE FAR NORTHWEST AND SOUTHERN JAMES RIVER VALLEY. WINDS
BEHIND THE COLD FRONT ARE NOT PROJECTED TO BE OVERLY STRONG,
BUT COULD STILL GUST TO NEAR 30 MPH IN FAR WESTERN NORTH DAKOTA
SUNDAY AFTERNOON. WITH HUMIDITY FALLING INTO THE 15 TO 25
PERCENT RANGE ACROSS THE WESTERN HALF OF THE STATE, AND PERHAPS
CLOSER TO 10 PERCENT IN THE FAR SOUTHWEST, AT LEAST NEAR-
CRITICAL FIRE WEATHER CONDITIONS ARE EXPECTED. THERE ARE
CURRENTLY TWO SEPARATE AREAS WITH THE HIGHEST PROBABILITIES FOR
MEETING RED FLAG WARNING CRITERIA ON SUNDAY: ONE ACROSS GOLDEN
VALLEY, SLOPE, AND BOWMAN COUNTIES AND ANOTHER IN EASTERN SIOUX,
WESTERN EMMONS, AND SOUTHERN BURLEIGH COUNTIES. BUT THESE
PROBABILITIES ARE STILL NOT QUITE HIGH ENOUGH FOR A FIRE WEATHER
WATCH, AND THE DISJOINTED AREAS OF HIGHEST PROBABILITIES LOWERS
CONFIDENCE IN SPATIAL COVERAGE. FURTHER COMPLICATING MATTERS IS
THAT EACH OF THE 2 AREAS OF CONCERN OCCUR AT DIFFERENT TIMES OF
DAY (EARLY AFTERNOON FAR SOUTHWEST AND MID TO LATE AFTERNOON
SOUTH CENTRAL). A FINAL NOTE ABOUT SUNDAY IS THAT HRRR/RAP
GUIDANCE PROJECTS A SIGNIFICANT INCREASE IN NEAR-SURFACE SMOKE
CONCENTRATIONS WITH THE ARRIVAL OF THE COLD FRONT, WHICH IS A
REGIME THE MODELING HAS PROVEN TO PERFORM WELL IN.
THE COLD FRONT IS FORECAST TO STALL FROM NORTHEAST TO SOUTH
CENTRAL NORTH DAKOTA SUNDAY EVENING AS ITS PARENT CYCLONE BEGINS
TO OCCLUDE OVER CENTRAL SASKATCHEWAN. IT IS VERY DOUBTFUL THAT
THE COLD FRONT WILL BE ABLE TO INITIATE ANY CONVECTION ON ITS
OWN PRIOR TO SUNSET SUNDAY EVENING, WITH STRONG CAPPING IN PLACE
AND STRONGER MID/UPPER LEVEL ASCENT LAGGING BEHIND. HEADING
INTO SUNDAY NIGHT THOUGH, SHORTWAVE ENERGY EMBEDDED IN SOUTHWEST
FLOW ALOFT COULD BEGIN TRAVERSING THE REGION AS THE RATE OF MID
LEVEL HEIGHT FALLS INCREASES, AND NORTHEASTWARD MOISTURE
TRANSPORT FROM THE NOCTURNAL LOW LEVEL JET IS ALSO FORECAST TO
STRENGTHEN. THIS INCREASES PROBABILITIES FOR ELEVATED CONVECTION
DEVELOPING OVER SOUTHERN AND EASTERN NORTH DAKOTA LATE SUNDAY
NIGHT INTO EARLY MONDAY MORNING. THE CHALLENGE WITH ELEVATED
CONVECTION IS DETERMINING THE CAPE/SHEAR PARAMETER SPACE OF ITS
ELEVATED INFLOW LAYER, WHICH ITSELF CARRIES LOW PREDICTABILITY.
NAM SOUNDINGS WOULD SUGGEST AN INFLOW LAYER WITH LITTLE TO NO
INHIBITION OF AT LEAST 3 KM AGL, AND THE ASSOCIATED HODOGRAPHS
DO SHOW SOME LENGTH AND CURVATURE FROM 3-11 KM (GFS SOUNDINGS
WERE BRIEFLY EXAMINED, BUT THINK ITS LOW-LEVEL MOISTURE DRY BIAS
IS INTERFERING). THE COUPLE OF CAMS THAT REACH THIS FORECAST
TIME RANGE DO SHOW SHOWERS AND STORMS DEVELOPING SUNDAY NIGHT,
BUT WITH VARYING COVERAGE AND INTENSITY.
ON MONDAY, THE STALLED FRONTAL BOUNDARY IS PROGGED TO SLOWLY
SHIFT EASTWARD AS A SEPARATE SHORTWAVE EJECTS OFF THE NORTHERN
ROCKIES. THIS SHORTWAVE WILL BRING A SECONDARY PUSH OF COOLER
AIR INTO THE REGION, WITH DAYTIME NORTH TO NORTHWEST WINDS
AROUND 25 MPH. THE HIGH TEMPERATURE FORECAST CONTINUES TO TREND
COOLER, NOW AT ONLY AROUND 70 IN THE FAR NORTHWEST TO AROUND 80
TO 85 SOUTH. BUT THE DEWPOINT FORECAST IS ALSO TRENDING LOWER,
KEEPING MINIMUM RH AS LOW AS 20-25 PERCENT IN THE SOUTHWEST.
EVEN THOUGH FIRE WEATHER CONCERNS WILL NOT BE AS WIDESPREAD ON
MONDAY COMPARED TO SUNDAY, THERE IS ACTUALLY A HIGHER
PROBABILITY OF MEETING RED FLAG CRITERIA IN SLOPE AND BOWMAN
COUNTIES. THE OTHER CONCERN FOR MONDAY IS WHETHER SEVERE STORMS
WILL DEVELOP WITHIN OUR FORECAST AREA OR REMAIN OFF TO THE EAST
(OR PERHAPS NOT DEVELOP AT ALL). IT SEEMS THAT THE MOST LIKELY
OUTCOME IS FOR SEVERE CONVECTION TO STAY JUST TO OUR EAST, AND
MORNING CONVECTION COULD EXERT INFLUENCE ON THE AFTERNOON
ENVIRONMENT. BUT THE NBM DOES SHOW LOW TO MEDIUM PROBABILITIES
FOR CAPE EXCEEDING 1000 J/KG IN THE SOUTHERN JAMES RIVER VALLEY,
WHICH WOULD EASILY BE SUFFICIENT FOR SEVERE STORMS GIVEN AROUND
50 KTS OF DEEP LAYER SHEAR. AND THE MENTIONED PROBABILITIES
WOULD ACTUALLY BE HIGHER AND EXTEND FARTHER BACK TO THE NORTH
AND WEST IF GEFS MEMBERS WERE EXCLUDED ON ACCOUNT OF THEIR LOW
CAPE BIASES.
CONFIDENCE REMAINS HIGH THAT TUESDAY WILL BE THE COOLEST DAY OF
THE WEEK WITH BELOW NORMAL HIGH TEMPERATURES IN THE 70S AS
SURFACE HIGH PRESSURE SLIDES IN UNDER LONGWAVE TROUGHING. A
QUICK RETURN TO NEAR OR ABOVE NORMAL TEMPERATURES IS THEN
FAVORED BY THE NBM THROUGH THE END OF THE WEEK. ENSEMBLE
CLUSTERS REMAIN UNDECIDED WHETHER THE NORTHERN PLAINS WILL BE
CLOSER TO THE RADIUS OF INFLUENCE OF A HUDSON BAY LOW OR ROCKIES
RIDGE. DESPITE THIS, MEAN 850 MB TEMPERATURES OF EACH CLUSTER
SHOW LITTLE DIFFERENCE THROUGH FRIDAY. ASIDE FROM THE SUNDAY
NIGHT/MONDAY TIME PERIOD, CHANCES FOR RAIN REMAIN VERY LOW. THIS
COULD CHANGE IF THE HUDSON BAY LOW ENDS UP DEEPER AND AUGMENTED
FARTHER WEST, BUT EVEN THEN THERE ARE NO SIGNS OF ANY
SIGNIFICANT RAIN-MAKERS ON THE HORIZON.
AVIATION /12Z TAFS THROUGH 12Z SUNDAY/
ISSUED AT 646 AM CDT SAT AUG 1 2026
PATCHY FOG HAS DEVELOPED AT KJMS, AND WAS REDUCING VISIBILITY
TO 1/4SM TO START THE FORECAST PERIOD. THE FOG SHOULD CLEAR BY
13-14Z. VFR CONDITIONS ARE OTHERWISE EXPECTED THROUGH THE
FORECAST PERIOD. SMOKE FROM DISTANT WILDFIRES MAY PERSIST ALOFT,
BUT IT IS UNLIKELY TO RESTRICT SURFACE VISIBILITY UNTIL SUNDAY
AFTERNOON. WINDS WILL BECOME SOUTHERLY AND INCREASE TO AROUND 15
KTS ACROSS SOUTHWEST AND CENTRAL NORTH DAKOTA LATER TODAY, WITH
LIGHTER SOUTHWESTERLY WINDS IN THE NORTHWEST AND SOUTHEASTERLY
WINDS AT KJMS. THEN THIS EVENING THROUGH TONIGHT, ALL TERMINALS
CAN EXPECT SOUTH-SOUTHEAST WINDS AROUND 15 KTS, WITH SOME HIGHER
GUSTS POSSIBLE.
BIS WATCHES/WARNINGS/ADVISORIES
NONE.
UPDATE...ANGLIN
DISCUSSION...HOLLAN
AVIATION...HOLLAN
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page