289
FXUS63 KBIS 170425
AFDBIS
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BISMARCK ND
1025 PM CST TUE DEC 16 2025
KEY MESSAGES
- A HIGH IMPACT WEATHER SYSTEM WILL MOVE THROUGH THE STATE
WEDNESDAY INTO THURSDAY, BRINGING VERY STRONG WINDS TO THE
ENTIRE AREA, AS WELL AS A MIX OF RAIN, FREEZING RAIN, AND
ACCUMULATING SNOW.
- ACCUMULATING SNOW ACROSS NORTHERN PARTS OF THE STATE COULD
COMBINE WITH THE WINDS TO PRODUCE BLIZZARD CONDITIONS
WEDNESDAY NIGHT. ANY LOCATION THAT SEES FALLING SNOW WITH THE
STRONG WINDS COULD EXPERIENCE A PERIOD OF NEAR BLIZZARD
CONDITIONS.
- COLDER ON THURSDAY, THEN WARMER ON FRIDAY AHEAD OF A WEAK
WEATHER SYSTEM MOVING THROUGH TO START THE WEEKEND.
UPDATE
ISSUED AT 1016 PM CST TUE DEC 16 2025
LEAD EMBEDDED WAVE GENERATING SOME ELEVATED RADAR RETURNS ACROSS
SOUTHEASTERN MONTANA, WITH THIS ACTIVITY MOVING EAST-SOUTHEAST
TOWARDS PARTS OF WESTERN NORTH DAKOTA. OPTED TO THROW IN SOME
SLIGHT CHANCE POPS, THOUGH WITH CLOUD BASES AT 10K FT AGL,
UNCERTAIN HOW MUCH IS REACHING THE SFC. ALSO MODIFIED POPS
OVERNIGHT, WITH MODELS NOT SHOWING MUCH OF ANYTHING ACROSS OUR
NORTH, SO SCALED BACK THERE ON THE FREEZING RAIN POTENTIAL. ALL
OTHER FORECAST ELEMENTS REMAIN ON TRACK FOR TONIGHT.
UPDATE
ISSUED AT 658 PM CST TUE DEC 16 2025
WEAKENING SURFACE GRADIENT AS SURFACE RIDGING HAS BUILT INTO
WESTERN/CENTRAL ND AND STABILIZING LOW LEVELS HAVE LED TO
DECREASING WINDS LATE IN THE AFTERNOON/EARLY EVENING AS FORECAST
THE WIND HAZARD PRODUCTS THAT WERE VALID THROUGH 00Z WERE
ALLOWED TO EXPIRE AS SCHEDULED EARLIER.
DISCUSSION
ISSUED AT 318 PM CST TUE DEC 16 2025
THIS AFTERNOON, BROADLY ZONAL FLOW DOMINATED THE SYNOPTIC
PATTERN ACROSS THE CONUS, WITH A DEEP SURFACE LOW ANALYZED OVER
ONTARIO. TO OUR WEST, HIGH PRESSURE WAS BUILDING OVER WESTERN
MONTANA, AND BEING BETWEEN THESE TWO FEATURES HAS LED TO A STOUT
PRESSURE GRADIENT AND SUBSEQUENT STRONG WINDS THROUGH THE DAY
TODAY. A FEW ISOLATED WIND GUSTS UP TO AROUND 60 MPH HAVE BEEN
OBSERVED, BUT THEY GENERALLY KEPT IN THE 50 TO 55 MPH RANGE.
THESE WINDS, ALONG WITH A PUSH OF LOW-LEVEL WARM AIR ADVECTION,
LED TO WIDESPREAD TEMPERATURES IN THE 40S EARLIER TODAY,
ALTHOUGH COLDER AIR IS STARTING TO FILTER INTO THE REGION AS
WINDS TURN MORE NORTHWESTERLY FROM A BACK DOOR COLD FRONT. THIS
FEATURE IS ALSO BRINGING IN SOME LOW CLOUDS TO OUR NORTH CENTRAL
COUNTIES, WITH ADDITIONAL HIGH CLOUDS ALONG THE SOUTHERN STATE
LINE. WINDS WILL DIMINISH THIS EVENING INTO THE OVERNIGHT HOURS.
A CLIMATOLOGICALLY ABNORMALLY DEEP LOW (PER NAEFS GUIDANCE) AND
ASSOCIATED UPPER WAVE IS PROGGED TO MOVE EAST ACROSS THE SOUTHERN
CANADIAN PRAIRIES ON WEDNESDAY, BEFORE BECOMING MORE STACKED AND
DROPPING SOUTH ACROSS THE NORTHERN PLAINS WEDNESDAY NIGHT INTO
THURSDAY. THIS WILL BRING A MYRIAD OF WEATHER TYPES AND HAZARDS
THROUGH LATE TONIGHT THROUGH - THURSDAY PERIOD, WITH
SIGNIFICANT IMPACTS POSSIBLE.
THERE IS NOT THE HIGHEST CONFIDENCE IN PRECIPITATION TIMING OR TYPE
TONIGHT. LATEST CAMS BRING A BAND OF MIXED PRECIPITATION ALONG THE
INTERNATIONAL BORDER GENERALLY FROM 06 TO 12 UTC TONIGHT, WITH NBM
PROBABILITIES PAINTING FREEZING RAIN AS THE DOMINANT P-TYPE.
HOWEVER, THIS FEATURE LOOKS PROGRESSIVE AND SHORT-LIVED AT ANY ONE
LOCATION, SOME HIGH-RES MODELS PUT THE BULK OF FREEZING RAIN NORTH
OF THE BORDER, AND SOME FORECAST SOUNDINGS KEEP SURFACE TEMPERATURES
ABOVE FREEZING WHEN PRECIPITATION IS EXPECTED, SO NOT A FOR SURE
THREAT COMPARED TO THE OTHER MIXED P-TYPE EVENTS WE'VE BEEN SEEING
LATELY.
AS THE SURFACE LOW BEGINS TO DEEPEN AS IT TRACKS ALONG THE
INTERNATIONAL BORDER, A SWATH OF RAIN WILL MOVE FROM WEST TO
EAST DURING THE DAY WEDNESDAY, WITH STRONG SOUTHERLY WINDS IN
THE WARM SECTOR OF THE SYSTEM. A RUMBLE OF THUNDER CANNOT BE
RULED OUT, WITH A FEW RUNS OF DETERMINISTIC GUIDANCE ADVERTISING
WEAK INSTABILITY FROM DAYTIME HEATING IN SOUTHWEST NORTH
DAKOTA. HIGH- RES AND BLENDED GUIDANCE ARE IN AGREEMENT ON A
MODEST BREAK IN PRECIPITATION BEHIND THE INITIAL WAVE OF RAIN
BEFORE THE FIRST PUSH OF COLD AIR ARRIVES AROUND 00 UTC
THURSDAY. SNOW QUICKLY MOVES IN WEDNESDAY EVENING AND SURGES
SOUTH AS THE CENTER OF THE LOW DROPS SOUTHEAST, WITH ADDITIONAL
PUSHES OF COLD AIR ADVECTION AND VERY STRONG WINDS. SNOW AMOUNTS
ARE RELATIVELY UNCHANGED FROM THE PREVIOUS FORECAST UPDATE,
WITH A GENERAL 1 TO 3 INCHES FROM DIVIDE AND WILLIAMS COUNTIES
TO WELLS AND FOSTER COUNTIES, AND SLIGHTLY HIGHER AMOUNTS OF 2
TO 4 INCHES IN THE ROLETTE COUNTY / TURTLE MOUNTAINS AREA, WHERE
THERE IS A MEDIUM CHANCE TO EXCEED 4 INCHES. LOWER SNOW AMOUNTS
ARE FORECAST TO THE SOUTH AND WEST. THERE ARE STILL SOME
QUESTIONS ON THE EXACT TRACK OF THE LOW, WITH THE ECMWF ENSEMBLE
FAVORING A TRACK ALONG THE INTERNATIONAL BORDER, WHILE THE GEFS
FOLLOWS THE HIGHWAY 2 CORRIDOR, WHICH COULD END UP INFLUENCING
HOW FAR SOUTH THE LIGHT SNOW ACCUMULATIONS GO.
DETERMINISTIC GUIDANCE, FORECAST SOUNDINGS, AND THE ECMWF EFI ARE
ALL IN STRONG AGREEMENT ON THIS BEING A VERY HIGH END WIND EVENT FOR
THE AREA. POTENT PRESSURE RISES AND COLD AIR ADVECTION WILL LEAD
TO A SIGNIFICANT PUSH OF WEST TO NORTHWEST WINDS. RIGHT NOW WE
HAVE VERY HIGH CONFIDENCE IN WIND GUSTS OF AT LEAST 60 MPH
ACROSS THE ENTIRE AREA, INCLUDING MODERATE POTENTIAL FOR WIND
GUSTS UP TO 70 MPH. IMPRESSIVELY, THE DETERMINISTIC NBM HAS
PROBABILITIES OF 10 TO 30 PERCENT FOR A WIND GUST OF AT LEAST 80
MPH OVER THE COURSE OF 24 HOURS ACROSS WESTERN NORTH DAKOTA.
FORECAST SOUNDINGS ARE STILL SHOWING A BRIEF PERIOD OF WINDS AT
THE TOP OF THE MIXED LAYER AROUND 75 KNOTS IN SOUTHWEST NORTH
DAKOTA, WHICH IS WHERE WE HAVE THE MOST CONCERN FOR POTENTIALLY
VERY HIGH END WINDS. THE 12Z EFI HAS THE SOUTHWEST HIGHLIGHTED
AT THE TOP OF CLIMATOLOGY PLUS A SHIFT OF TAILS, WHICH GETS OUR
ATTENTION FOR AN EXTREME EVENT. ELSEWHERE ACROSS THE FORECAST
AREA THESE MIXED LAYER WINDS TOP OUT AROUND 50 TO 60 KNOTS, SO
THE CEILING FOR THOSE VERY HIGH END WIND GUSTS IS A LITTLE
LOWER.
THE PERIOD OF MOST SIGNIFICANT IMPACTS IS LIKELY TO BE 00 TO 12
UTC THURSDAY (WEDNESDAY NIGHT). THIS IS WHEN THE MAJORITY OF
SNOW IS EXPECTED TO FALL, WHICH WILL BE NEEDED FOR BLOWING SNOW DUE
TO A LACK OF BLOWABLE SNOWPACK FROM THE SEASONABLY WARM
TEMPERATURES THE PAST FEW DAYS. NAM AND RAP GUIDANCE ARE STILL
ADVERTISING A VERY ELEVATED SNOW SQUALL PARAMETER DURING THIS
PERIOD AS WELL, HIGHEST IN SOUTHWEST NORTH DAKOTA, WHERE THE
HREF IS PRODUCING SIGNIFICANT VISIBILITY REDUCTIONS. THE
QUESTION WILL THEN BECOME HOW LONG-LIVED ARE THOSE REDUCTIONS
WHEN THINKING ABOUT A BLIZZARD COMPARED TO A SNOW SQUALL.
THESE TYPES OF EVENTS ARE VERY TRICKY FORECAST AND HEADLINE-WISE. WE
ARE EXTREMELY CONFIDENT IN THIS BEING A HIGH-END WIND EVENT FOR THE
FORECAST AREA, BUT HAVING LIGHT SNOW ACCUMULATIONS QUICKLY MAKES
THINGS MORE COMPLICATED DUE TO BLOWING SNOW AND ASSOCIATED IMPACTS.
THE HEADLINES/ALERTS AT OUR DISPOSAL TO POTENTIALLY USE WITH
THIS SYSTEM ARE THE WINTER STORM WATCH (WHICH WOULD BE UPGRADED
TO A BLIZZARD WARNING), WINTER WEATHER ADVISORY, AND SNOW SQUALL
WARNINGS. ALTHOUGH WE DID DISCUSS AN EXPANSION OF THE CURRENT
WINTER STORM WATCH ON THIS SHIFT, WE OPTED TO KEEP THINGS
SIMPLE UNTIL WE GOT A BETTER FEEL FOR THE AREA OF SNOW
ACCUMULATIONS, SINCE THE SIGNIFICANT VISIBILITY REDUCTIONS WILL
BE ENTIRELY DEPENDENT ON FALLING / FRESH SNOW. WE ALSO WANT TO
KEEP EMPHASIZING THAT CONDITIONS OUTSIDE OF THE WINTER STORM
WATCH WILL LIKELY BE QUITE HAZARDOUS, AND THERE IS ESPECIALLY
CONCERN IN THE SOUTHWEST WHERE THE STRONGEST WINDS ARE FAVORED,
WHICH COULD LEAD TO VERY IMPACTFUL WEATHER IF COMBINED WITH SNOW
SQUALLS / SNOW SHOWERS. OVERALL, WE DO NOT WANT TO STRICTLY
FOCUS ON WHAT HEADLINE IS IN EFFECT BECAUSE IT'S A MULTI-FACETED
STORM SYSTEM, AND INSTEAD FOCUS ON THE EXPECTED HAZARDS.
TEMPERATURES WILL DROP INTO THE SINGLE DIGITS BELOW ZERO ACROSS
THE NORTH WEDNESDAY NIGHT, AS THE COLDER ARCTIC AIR MASS PUSHES
INTO THE REGION. THE STACKED LOW QUICKLY EXITS THE AREA ON
THURSDAY, WITH WINDS DECREASING AND CONDITIONS IMPROVING FROM
WEST TO EAST THROUGH THE DAY, ALTHOUGH COLD TEMPERATURES ACROSS
CENTRAL NORTH DAKOTA WILL LEAD TO WIND CHILL VALUES IN THE 20
BELOW ZERO RANGE. TEMPERATURES START TO REBOUND ACROSS WESTERN
NORTH DAKOTA AS A SHALLOW RIDGE BUILDS IN, WHICH WILL LEAD TO A
WIDE RANGE OF TEMPERATURES ON FRIDAY: FROM THE MID 20S IN THE
TURTLE MOUNTAINS TO THE MID 40S SOUTHWEST. A RIDGE-RIDING WAVE
WILL ALSO MOVE THROUGH ON FRIDAY, WITH BROAD 30 TO 50 POPS EARLY
FRIDAY MORNING THROUGH THE DAY AND INTO THE EVENING. THE MOST
LIKELY SCENARIO IS AN INCH OR TWO OF NEW SNOW ACROSS THE NORTH,
AND LITTLE TO NO ACCUMULATION SOUTH. COOLER ON SATURDAY,
ESPECIALLY NORTH, WITH SOME SCATTERED LOW CHANCES OF LIGHT SNOW
THROUGH THE WEEKEND.
LOOKING AHEAD TO NEXT WEEK, THE BROAD SYNOPTIC PATTERN ADVERTISED
AMONG ENSEMBLE MEMBERS IS FOR TROUGHING WELL OFF THE WEST COAST,
LEADING TO THE RIDGE AXIS BEING PLACED GENERALLY ACROSS THE CENTRAL
CONUS. NBM PRECIPITATION PROBABILITIES ARE LOW BUT STEADY, GENERALLY
15 TO 20 PERCENT INTO MIDWEEK NEXT WEEK AS VARIOUS LOW AMPLITUDE
WAVES RIDE THE RIDGE AXIS. TEMPERATURE PERCENTILES CONTINUE TO HAVE
A LARGE SPREAD, SIGNALING LOW CONFIDENCE IN THE FORECAST, BUT
WOULD NOT BE SURPRISED TO HAVE A WIDE TEMPERATURE RANGE FROM
NORTH CENTRAL TO SOUTHWEST ACROSS THE FORECAST AREA DURING THIS
PERIOD.
AVIATION /06Z TAFS THROUGH 06Z THURSDAY/
ISSUED AT 1016 PM CST TUE DEC 16 2025
VFR CONDITIONS PREVAIL TONIGHT AND THROUGH THE MAJORITY OF THE
06Z PERIOD. WINDS SHIFT TO MORE SOUTH-SOUTHWEST LATER TONIGHT
IN RESPONSE TO LOW PRESSURE BUILDING UPSTREAM. LOW PRESSURE WILL
STRENGTHEN AND MOVE EAST INTO THE REGION WED AFT/EVE, BRINGING A
COLD FROPA INTO THE REGION, RESULTING IN INCREASING WESTERLY
WINDS WEST INTO CENTRAL WEDNESDAY AFTERNOON AND EVENING,
IMPACTING ALL TERMINALS (WIND GUSTS IN EXCESS OF 50 KNOTS
LIKELY). ALONG THE FRONTAL ZONE, A TRANSITION FROM RAIN TO SNOW
IS FORECAST, WITH THE STRONG WINDS AND FALLING SNOW POSSIBLY
REDUCING VISIBILITY WED EVENING. AHEAD OF THIS FRONTAL ZONE, A
SOUTHWEST ORIENTATED LLJ (45-55KT) DEVELOPS AND MAY BRING A
PERIOD OF LOW LEVEL WIND SHEAR TO LOCATIONS ACROSS WESTERN AND
CENTRAL ND.
BIS WATCHES/WARNINGS/ADVISORIES
HIGH WIND WATCH FROM WEDNESDAY AFTERNOON THROUGH THURSDAY
MORNING FOR NDZ001-009-010-017-018-031>033-040-041-043-044.
WINTER STORM WATCH FROM WEDNESDAY EVENING THROUGH THURSDAY
MORNING FOR NDZ002>005-011>013.
HIGH WIND WATCH FROM WEDNESDAY AFTERNOON THROUGH THURSDAY
AFTERNOON FOR NDZ019>023-025-034>037-042-045>048-050-051.
UPDATE...NH
DISCUSSION...JONES
AVIATION...NH
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page