592
FXUS63 KBIS 061659
AFDBIS
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BISMARCK ND
1159 AM CDT TUE OCT 6 2026
KEY MESSAGES
- DRY WEATHER AND NEAR TO ABOVE NORMAL TEMPERATURES ARE EXPECTED
THROUGH THE WORK WEEK, POSSIBLY LASTING INTO SATURDAY.
- MUCH COLDER TEMPERATURES WITH MEDIUM CHANCES FOR PRECIPITATION
ARRIVE FOR THE SECOND HALF OF THE WEEKEND INTO EARLY NEXT
WEEK.
UPDATE
ISSUED AT 1152 AM CDT TUE OCT 6 2026
CURRENT FORECAST REMAINS ON TRACK. NO UPDATES NEEDED AT THIS
TIME.
UPDATE
ISSUED AT 929 AM CDT TUE OCT 6 2026
A FEW HIGH CLOUDS STREAMING BY THIS MORNING, OTHERWISE QUIET
WEATHER IS IN STORE TODAY. MADE A FEW ADJUSTMENTS TO SKY COVER
BASED ON LATEST SATELLITE IMAGERY, OTHERWISE NO CHANGES NEEDED
TO THE GOING FORECAST.
UPDATE
ISSUED AT 643 AM CDT TUE OCT 6 2026
THE EARLY MORNING FORECAST REMAINS IN GOOD SHAPE. CURRENT
CONDITIONS AND TRENDS WERE BLENDED IN FOR THIS UPDATE. DESPITE
SOME HIGHER CLOUDS, EARLY MORNING TEMPERATURES HAVE FALLEN AS
LOW AS THE MID 30S ON AN ISOLATED BASIS ACROSS LOW-LYING AREAS
OF WESTERN NORTH DAKOTA.
DISCUSSION
ISSUED AT 357 AM CDT TUE OCT 6 2026
A NORTHWEST UPPER FLOW PATTERN IS FORECAST TO PERSIST OVER THE
NORTHERN PLAINS TODAY THROUGH THURSDAY. A PROGRESSIVE SHORTWAVE
MOVING THROUGH MANITOBA AND ONTARIO WILL PUSH A COOLER AIR MASS
INTO THE STATE FROM NORTH TO SOUTH LATER TODAY THROUGH TONIGHT.
HIGH TEMPERATURES TODAY ARE FORECAST TO RANGE FROM THE UPPER 60S
NORTH TO UPPER 70S SOUTH. SURFACE HIGH PRESSURE BUILDING OFF
THE NORTHERN ROCKIES BEHIND A WARM FRONT EXITING THE RED RIVER
VALLEY THIS MORNING WILL PRODUCE NORTHWEST WINDS AROUND 15 TO 20
MPH THIS AFTERNOON, STRONGEST IN THE FAR SOUTHWEST WHERE RH AS
LOW AS 20 PERCENT COULD YIELD NEAR-CRITICAL FIRE WEATHER
CONDITIONS. SURFACE WINDS RELAX TONIGHT AS THE HIGH PRESSURE
CONTINUES TO BUILD EASTWARD, BUT MID TO HIGH CLOUDS MAY PREVENT
OVERNIGHT TEMPERATURES FROM TANKING TO NEAR-FREEZING. CAMS SHOW
THAT A BAND OF LOWER TO MID LEVEL FRONTOGENESIS MAY PRODUCE SOME
LIGHT RAIN SHOWERS FROM NORTH CENTRAL INTO NORTHEAST NORTH
DAKOTA LATE TONIGHT INTO WEDNESDAY MORNING, BUT A DRY LOW LEVEL
LAYER OF AIR WILL LIKELY PREVENT MEASURABLE PRECIPITATION AT THE
SURFACE.
WEDNESDAY WILL BE COOLER, BUT STILL SEASONABLE WITH HIGHS IN
THE LOWER 60S TO LOWER 70S. A SECONDARY PUSH OF COOLER AND DRIER
AIR WILL REORIENT THE SURFACE RIDGE AXIS FROM CENTRAL ALBERTA
TO SOUTHWEST NORTH DAKOTA, RESULTING IN A BREEZY AFTERNOON FOR
THE EASTERN HALF OF THE STATE. THE BROAD SURFACE RIDGE THEN
FOCUSES MORE SQUARELY OVER THE REGION WEDNESDAY NIGHT, BUT MID
TO HIGH CLOUDS COULD ONCE AGAIN PREVENT TEMPERATURES FROM
FALLING BELOW FREEZING. IT IS LIKELY TO BE COOLER WEDNESDAY
NIGHT THAN TONIGHT THOUGH, WITH LOWS MOSTLY IN THE MID 30S TO
LOWER 40S. THURSDAY LOOKS TO BE LESS BREEZY WITH A SIMILAR HIGH
TEMPERATURE FORECAST IN THE LOWER 60S TO LOWER 70S AS THE BROAD
SURFACE RIDGE LINGERS OVER THE REGION.
A POTENT TROUGH DIGGING INTO BRITISH COLUMBIA AND THE PACIFIC
NORTHWEST ON FRIDAY WILL FORCE LOW AMPLITUDE RIDGING OVER THE
NORTHERN PLAINS, QUICKLY TRANSITIONING TO SOUTHWEST FLOW ALOFT
AS THE LONGWAVE TROUGH CONTINUES DEEPENING ALONG THE PACIFIC
COAST. ENSEMBLE GUIDANCE IS IN GOOD AGREEMENT ON THE PHASING OF
SYNOPTIC SCALE FEATURES THROUGH FRIDAY NIGHT, WHEN THE HEART OF
THE LOW LEVEL THERMAL RIDGE IS FORECAST TO PASS THROUGH THE
REGION. WARM AIR ADVECTION COMMENCES IN TIME TO BRING FRIDAY'S
HIGH TEMPERATURE FORECAST NEAR 80 IN FAR SOUTHWEST NORTH DAKOTA,
WITH 70S FAVORED FOR MOST OTHER PARTS OF THE FORECAST AREA.
THERE IS HIGH CONFIDENCE THAT A MUCH COLDER AIR MASS WILL ENTER
THE REGION SOMETIME OVER THE WEEKEND, BUT THE TIMING OF THE COLD
FRONTAL PASSAGE THROUGH CENTRAL NORTH DAKOTA RANGES FROM AS
EARLY AS DURING THE DAY SATURDAY (HEAVILY FAVORED BY THE GEFS)
TO AS LATE AS DURING THE DAY SUNDAY (AN ENSEMBLE CLUSTER WITH 37
PERCENT OF THE TOTAL MEMBERSHIP). THIS LENDS TO LARGE SPREADS
IN THE NBM HIGH TEMPERATURE DISTRIBUTION ON SATURDAY, WITH THE
50TH PERCENTILE MAINTAINING AROUND 60 DEGREES NORTHWEST TO NEAR
80 SOUTHEAST. THAT DRASTICALLY CHANGES ON SUNDAY, WHEN THERE IS
SMALLER ENSEMBLE SPREAD AND HIGHER CONFIDENCE IN DAYTIME MAXIMUM
TEMPERATURES ONLY IN THE 40S WEST AND NORTH TO 50S SOUTH
CENTRAL AND SOUTHEAST. HIGH TEMPERATURES SIMILAR TO THESE REMAIN
IN THE FORECAST THROUGH MONDAY, WITH ONLY A SLIGHT WARMING
TREND THEREAFTER. THERE WILL ALSO BE A POTENTIAL FOR WIDESPREAD
SUB- FREEZING TEMPERATURES BOTH SUNDAY AND MONDAY NIGHTS.
THE NBM INCREASES PRECIPITATION CHANCES TO AROUND 30 TO 60
PERCENT ACROSS MUCH OF THE AREA FROM LATE SATURDAY THROUGH
SUNDAY AND INTO MONDAY. THIS LINES UP WELL WITH RAW GLOBAL
ENSEMBLE QPF PROBABILITIES. BOTH SETS OF GUIDANCE FAVOR LIGHT
QPF, WITH ONLY LOW TO MEDIUM CHANCES FOR EXCEEDING 0.25" OVER
ANY GIVEN 24-HOUR PERIOD. THIS CORRESPONDS WELL TO THE EVIDENT
UNCERTAINTY IN THE EVOLUTION OF THE WESTERN CONUS TROUGH AND
WHAT DOWNSTREAM FORCING MECHANISMS COULD LINE UP TO PRODUCE
APPRECIABLE PRECIPITATION. A COUPLE ENSEMBLE CLUSTERS DO HINT AT
A NORTHERN STREAM SHORTWAVE CUTTING OFF FROM THE WESTERN
TROUGH, AND THIS OUTCOME IS LIKELY THE MOST CONTRIBUTIVE TO THE
AFOREMENTIONED 30 TO 60 PERCENT POPS SUNDAY INTO MONDAY. NBM LOW
TEMPERATURES IN THE LOWER TO MID 30S SUNDAY NIGHT HAS ALLOWED A
RAIN/SNOW MIX TO ENTER THE FORECAST, AND THAT ACTUALLY
CORRESPONDS WELL TO LOW NBM PROBABILITIES FOR MEASURABLE SNOW
THAT ARE NO GREATER THAN 20 PERCENT IN THE SOUTHWEST, AND NO
GREATER THAN 10 PERCENT ELSEWHERE.
TWO ENSEMBLE CLUSTERS CONSTITUTING 60 PERCENT OF THE TOTAL
MEMBERSHIP KEEP THE BASE OF THE LONGWAVE TROUGH OVER THE DESERT
SOUTHWEST THROUGH TUESDAY, AND A SINGULAR CLUSTER WITH 40
PERCENT MEMBERSHIP FAVORS THE TROUGH KICKING INTO THE NORTHERN
AND CENTRAL PLAINS AROUND MID WEEK, AKIN TO THE 00Z
DETERMINISTIC GFS AND ECMWF. THIS OUTCOME COULD PRODUCE A SYSTEM
WITH A HIGHER PRECIPITATION CEILING, BUT ONLY FOR SOME PARTS OF
THE REGION AND WITH VERY HIGH PROBABILITIES FOR ONLY RAIN AS A
PRECIPITATION TYPE.
AVIATION /18Z TAFS THROUGH 18Z WEDNESDAY/
ISSUED AT 1152 AM CDT TUE OCT 6 2026
VFR CONDITIONS ARE EXPECTED THROUGH THE 18Z TAF PERIOD. EXPECT
MAINLY NORTHWEST TO NORTH WINDS 10-15KTS THIS AFTERNOON WITH A
FEW GUSTS TO AROUND 20 KTS. WINDS DIMINISH THIS EVENING AND
THEN PICK UP AGAIN 5 TO 15 KTS WEDNESDAY MORNING FROM THE WEST
TO NORTHWEST.
BIS WATCHES/WARNINGS/ADVISORIES
NONE.
UPDATE...TWH
DISCUSSION...HOLLAN
AVIATION...TWH
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