542
FXUS63 KBIS 191108
AFDBIS
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BISMARCK ND
508 AM CST FRI DEC 19 2025
KEY MESSAGES
- LIGHT MIXED PRECIPITATION WILL MOVE FROM WEST TO EAST ACROSS
THE STATE THIS MORNING AND EARLY AFTERNOON. THE HIGHEST
CHANCES FOR ACCUMULATING ICE ARE WEST OF HIGHWAY 83.
- A PERIOD OF SNOW AND BLOWING SNOW WILL IMPACT AREAS FROM
AROUND THE TURTLE MOUNTAINS TO NORTHERN JAMES RIVER VALLEY
THIS MORNING AND EARLY AFTERNOON.
- STRONG WEST WINDS GUSTING AS HIGH AS 55 MPH ARE EXPECTED
ACROSS NORTHERN NORTH DAKOTA THIS AFTERNOON AND EVENING.
- HIGHS ABOVE FREEZING IN THE WESTERN HALF OF THE STATE TODAY.
THEN AFTER A COOLER SATURDAY, TEMPERATURES ARE FAVORED TO WARM
BACK TO NEAR OR ABOVE AVERAGE THROUGH CHRISTMAS DAY. A LARGE
TEMPERATURE SPREAD FROM NORTHEAST (COLDEST) TO SOUTHWEST
(WARMEST) CAN BE EXPECTED MOST DAYS.
DISCUSSION
ISSUED AT 507 AM CST FRI DEC 19 2025
ANOTHER CLIPPER SYSTEM WILL IMPACT THE REGION TODAY, BUT TO A MUCH
LESSER EXTENT THAN THE ONE WEDNESDAY NIGHT/YESTERDAY. THIS SYSTEM IS
NOT NEARLY AS POWERFUL, BUT STILL FEATURES SEVERAL DIFFERENT
COMPONENTS THAT WILL BRING DIFFERENT HAZARDS TO DIFFERENT AREAS AT
DIFFERENT TIMES.
FIRST UP THIS MORNING IS THE LEADING WARM FRONT/MID LEVEL SHORTWAVE
THAT IS FORECAST TO BRING A MERIDIONAL BAND OF MIXED PRECIPITATION
ACROSS THE STATE FROM WEST TO EAST THIS MORNING AND EARLY AFTERNOON.
AS OF 5 AM CST, THE PRECIPITATION HAD ALREADY CROSSED INTO NORTHWEST
NORTH DAKOTA WITH SNOW REPORTED AT WILLISTON, BUT AN UPSTREAM
AUTOMATED OBSERVATION AT PLENTYWOOD, MT DID REPORT AN UNKNOWN
PRECIPITATION TYPE IN THE PREVIOUS 1-2 HOURS. THE FORCING
RESPONSIBLE FOR THIS PRECIPITATION DOES EXTEND SOUTHWARD THROUGH THE
SOUTH DAKOTA STATELINE, BUT THERE IS DRIER AIR TO WORK THROUGH OVER
SOUTHERN NORTH DAKOTA, SO IT MAY TAKE A LITTLE WHILE LONGER UNTIL WE
STARTING SEEING PRECIPITATION REACH THE SURFACE THERE. CONFIDENCE IS
HIGH IN A TRADITIONAL SNOW-TO-SLEET-TO-FREEZING RAIN TRANSITION AS
MAXIMUM TEMPERATURES ALOFT STEADILY RISE TO ABOVE FREEZING. THIS
DOES INCLUDE A CORRIDOR OF HIGHER THAN NORMAL PROBABILITIES FOR
SLEET AS A DOMINANT PRECIPITATION TYPE. IN SOUTHERN NORTH DAKOTA,
TYPES WILL BE MORE DEPENDENT ON COLUMN SATURATION, AND COULD GO
STRAIGHT TO SLEET OR FREEZING RAIN AT THE ONSET. AN AREA ENCLOSED BY
HIGHWAY 83 AND THE STATE BORDERS HAS CONSISTENTLY BEEN SHOWN AS
HAVING THE HIGHEST PROBABILITIES FOR ACCUMULATING ICE THROUGH THIS
MORNING. THEREFORE, WE HAVE ISSUED A WINTER WEATHER ADVISORY FOR
COUNTIES WEST OF (BUT NOT INCLUDING) HIGHWAY 83. AN EASTWARD
EXPANSION OF THE ADVISORY MAY BE NEEDED LATER THIS MORNING, BUT
THERE IS GREATER UNCERTAINTY IN DOMINANT PRECIPITATION TYPES MOVING
EASTWARD, AND LIGHT FREEZING RAIN DOES TEND TO BE LESS IMPACTFUL
DURING PEAK SOLAR HEATING. BUT THERE ARE STILL MEDIUM CHANCES FOR
MIXED PRECIPITATION EAST OF HIGHWAY 83 AND SOUTH OF HIGHWAY 200
DURING THE LATE MORNING AND EARLY AFTERNOON.
A SEPARATE, BUT YET RELATED SET OF HAZARDS IS POISED TO IMPACT PARTS
OF NORTH CENTRAL NORTH DAKOTA THIS MORNING AND AFTERNOON,
SPECIFICALLY AREAS FROM AROUND THE TURTLE MOUNTAINS, THROUGH THE
DEVILS LAKE BASIN, AND INTO THE NORTHERN JAMES RIVER VALLEY.
CONFIDENCE IN A LONGER DURATION OF SNOW FROM THE WARM FRONTAL BAND
IS HIGHEST IN THIS PART OF OUR FORECAST AREA, AND THE CHANCE OF
TRANSITIONING TO SLEET OR FREEZING RAIN BEFORE PRECIPITATION DEPARTS
IS LOWER HERE. THE NBM SHOWS MEDIUM TO HIGH CHANCES FOR AT LEAST 1
INCH OF SNOW IN THIS PART OF THE STATE, AND MEDIUM CHANCES FOR AT
LEAST 2 INCHES ALONG THE SOUTHERN SLOPES OF THE TURTLE MOUNTAINS
WHERE STRONG SOUTHERLY LOW LEVEL FLOW COULD PROVIDE OROGRAPHIC
ENHANCEMENT. THE SOUTHERLY SURFACE WINDS, WHICH COULD REACH
SUSTAINED SPEEDS AROUND 20 TO 30 MPH AND GUST AS HIGH AS 40 MPH
DURING THE SNOWFALL, ARE MODELED TO PRODUCE IMPACTFUL BLOWING SNOW
ACROSS THIS AREA, PROMPTING THE ISSUANCE OF A WINTER WEATHER
ADVISORY.
TRAILING THE PRECIPITATION, TEMPERATURES ARE FORECAST TO RISE ABOVE
FREEZING ACROSS THE WESTERN HALF OF THE STATE THIS AFTERNOON, AND
COULD APPROACH 50 IN THE SOUTHWEST. WE BLENDED IN WARMER NBM
PERCENTILES WHERE CONFIDENCE IS HIGHEST IN A WESTERLY COMPONENT OF
NEAR-SURFACE LEVEL WINDS PRIOR TO THE CONCLUSION OF PEAK DIURNAL
HEATING. BUT ALSO DURING THE AFTERNOON, THE COLD FRONT ATTENDANT TO
THE CLIPPER IS FORECAST TO BEGIN DROPPING DOWN FROM CANADA, PUSHING
SOUTHEASTWARD THROUGH THE EARLY EVENING. AGAIN, THIS SYSTEM DOES NOT
CONTAIN NEARLY AS STRONG KINEMATICS AS THE PREVIOUS ONE. HOWEVER,
THERE ARE STILL SIGNALS FOR STRONG COLD AIR ADVECTION AND MODEST
PRESSURE RISES WITH MEAN 900-800 MB WINDS AS HIGH AS 50-55 KTS. BUT
THERE ARE TWO FACTORS SHOWING UP IN MODEL SOUNDINGS THAT COULD LIMIT
MOMENTUM TRANSFER TO THE SURFACE. FIRST, THE POST-FRONTAL BOUNDARY
LAYER IS FORECAST TO BE SHALLOW, WITH MIXING HEIGHTS BARLEY REACHING
850 MB. SECOND, NUMEROUS MODEL SOUNDINGS DO NOT SHOW A FULLY MIXED
NEAR SURFACE LAYER, LIKELY ON ACCOUNT OF SNOW COVER INHERITED FROM
MODEL INITIAL CONDITIONS. WHILE THERE CERTAINLY IS SNOW ON THE
GROUND, WE QUESTION WHETHER IT IS SUFFICIENT TO PREVENT FULL
MOMENTUM TRANSFER POTENTIAL AT THE SURFACE. IN NORTHERN PARTS OF THE
STATE, FROM THE MONTANA BORDER TO AROUND HIGHWAY 83, THERE IS HIGHER
CONFIDENCE IN STRONGER MOMENTUM TRANSFER OF 45 TO 55 MPH GUSTS TO
THE SURFACE. A WIND ADVISORY HAS THEREFORE BEEN ISSUED THERE FOR
THIS AFTERNOON AND EVENING. THE CORE OF THE MAXIMUM WINDS ALOFT IS
FORECAST TO REMAIN DRAPED ALONG THE CANADIAN BORDER THIS EVENING
OVER SUSTAINED COLD AIR ADVECTION AND PRESSURE RISES. THE WIND
ADVISORY MAY EVENTUALLY REQUIRE AN EASTWARD EXPANSION. BUT IF WINDS
THAT STRONG ARE REALIZED EAST OF HIGHWAY 83, THERE MAY ACTUALLY BE A
NEED FOR ANOTHER WINTER WEATHER ADVISORY FOR BLOWING SNOW IMPACTS
LATER TODAY. THERE IS ENOUGH FORECAST CONFIDENCE IN A FEW HOURS OF A
BREAK BETWEEN THE MORNING/EARLY AFTERNOON IMPACTS AND POTENTIAL LATE
AFTERNOON/EVENING IMPACTS TO REFRAIN FROM ISSUING FURTHER HEADLINES
IN THIS PART OF THE STATE, THOUGH IT SEEMS MORE LIKELY THAN NOT THAT
AREAS EAST OF THE WIND ADVISORY WILL NEED SOME SORT OF HEADLINE THIS
EVENING.
WINDS ALOFT ARE NOT FORECAST TO BE AS STRONG BEHIND THE COLD FRONTAL
PASSAGE ACROSS SOUTHERN NORTH DAKOTA, BUT IT WILL STILL BE BREEZY.
THERE IS ALSO ENSEMBLE SUPPORT FOR MID LEVEL FRONTOGENESIS TRAILING
THE COLD FRONT PRODUCING LIGHT MIXED PRECIPITATION ALONG AND SOUTH
OF I-94 LATE THIS AFTERNOON AND EVENING. CAMS GENERALLY IMPLY A
MESSY LIQUID TO SNOW TRANSITION, WITH RAIN VS. FREEZING RAIN DEFINED
BY SURFACE TEMPERATURE. CHANCES FOR ACCUMULATING ICE IN THIS PART OF
THE STATE AT THIS TIME OF DAY ARE MUCH LOWER THAN THEY ARE THIS
MORNING, BUT STILL NOT ZERO.
BY EARLY SATURDAY MORNING, TEMPERATURES ARE FORECAST TO FALL INTO
THE SINGLE DIGITS BELOW ZERO NORTH AND SINGLE DIGITS TO LOWER TEENS
ABOVE SOUTH. A FEW AREAS ALONG THE CANADIAN BORDER COULD ONCE AGAIN
TOUCH ON COLD WEATHER ADVISORY CRITERIA WIND CHILLS AS LOW AS 30
BELOW. SATURDAY AFTERNOON FEATURES THE COLDEST HIGH TEMPERATURE
FORECAST FOR THE SEVEN-DAY PERIOD, RANGING FROM AROUND ZERO FAR
NORTH TO NEAR 30 FAR SOUTHWEST. A PERIOD OF ANTICYCLONIC NORTHWEST
FLOW TRANSITIONING TO BROAD UPPER LEVEL RIDGING OVER THE CENTRAL
CONUS IS FAVORED BY LONG-RANGE ENSEMBLE GUIDANCE SUNDAY THROUGH
CHRISTMAS EVE. THE SYNOPTIC PATTERN THEN BECOMES MUCH MORE UNCERTAIN
FOR CHRISTMAS DAY AS ENSEMBLE CLUSTER ANALYSIS PROVIDES A VARIETY OF
OUTCOMES. THE FAVORED PATTERN FROM SUNDAY THROUGH CHRISTMAS EVE
SUPPORTS NEAR TO ABOVE NORMAL TEMPERATURES, AND THE NBM STILL SHOWS
A DAILY STRONG CONTRAST IN HIGHS FROM COOLEST NORTHEAST TO WARMEST
SOUTHWEST. DETERMINISTIC GUIDANCE DOES SHOW THAT A SHORTWAVE OR TWO
COULD STILL CUT THROUGH THE BUILDING RIDGE OVER THIS TIME PERIOD,
BUT PREDICTABILITY IS NOT HIGH ENOUGH TO INCLUDE MENTIONABLE CHANCES
FOR PRECIPITATION IN THE FORECAST AT THIS TIME.
AVIATION /06Z TAFS THROUGH 06Z SATURDAY/
ISSUED AT 1150 PM CST THU DEC 18 2025
VFR CONDITIONS ALL TERMINALS EARLY IN THE 06Z PERIOD, WITH
INCREASING MID TO UPPER LEVEL CLOUDS WEST TO EAST. WINDS WILL
TRANSITION TO SOUTHERLY, AND INCREASE THROUGH THE NIGHT AS AN AREA
OF SURFACE LOW PRESSURE APPROACHES. AFTER 09Z, AN AREA OF SNOW MIXED
WITH FREEZING RAIN AND SLEET IS FORECAST TO MOVE FROM WEST TO EAST
ACROSS THE STATE THROUGH FRIDAY MORNING, MAYBE LINGERING INTO EARLY
AFTERNOON FOR KJMS. THIS COULD BRING MVFR TO IFR CONDITIONS, THOUGH
CONFIDENCE OF THIS OCCURRING AT ANY GIVEN TERMINAL IS LOW. WINDS
BECOME MORE WESTERLY AS WE PROGRESS THROUGH THE DAY FRIDAY, PERHAPS
LEADING TO SOME BLOWING SNOW AND LOW LEVEL WIND SHEAR ISSUES.
BIS WATCHES/WARNINGS/ADVISORIES
WINTER WEATHER ADVISORY UNTIL NOON CST /11 AM MST/ TODAY FOR
NDZ001-002-009-010-017>020-031>034-040>045.
WIND ADVISORY FROM NOON TODAY TO MIDNIGHT CST TONIGHT FOR
NDZ001>003-009>011.
COLD WEATHER ADVISORY UNTIL NOON CST TODAY FOR NDZ004-005-012-
013.
WINTER WEATHER ADVISORY UNTIL 2 PM CST THIS AFTERNOON FOR
NDZ004-005-012-013-023-025.
DISCUSSION...HOLLAN
AVIATION...NH
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