621
FXUS63 KBIS 161512
AFDBIS
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BISMARCK ND
912 AM CST TUE DEC 16 2025
KEY MESSAGES
- TEMPERATURES WILL REMAIN ABOVE NORMAL THROUGH WEDNESDAY, WITH
WINDY CONDITIONS BOTH TUESDAY AND WEDNESDAY. A WIND ADVISORY
REMAINS IN EFFECT THROUGH THIS AFTERNOON FOR WIND GUSTS UP 55
MPH.
- HIGH WIND WATCH HAS BEEN ISSUED FOR WINDS UP TO 70 MPH
WEDNESDAY AFTERNOON THROUGH THURSDAY MORNING. A WINTER STORM
WATCH HAS ALSO BEEN ISSUED FOR THE NORTH CENTRAL FOR POSSIBLE
BLIZZARD CONDITIONS STARTING WEDNESDAY NIGHT.
- A TREND BACK TO COLDER TEMPERATURES IS EXPECTED FOR THE
LATTER HALF OF THE WEEK. HOWEVER, BOTH HIGHS AND LOWS WILL
VARY GREATLY FROM NORTHEAST (COOLER) TO SOUTHWEST (WARMER).
UPDATE
ISSUED AT 912 AM CST TUE DEC 16 2025
THE FORECAST AREA IS SANDWICHED BETWEEN A SURFACE LOW ANALYZED
IN EAST-CENTRAL MANITOBA AND A SURFACE HIGH BUILDING OVER
WESTERN MONTANA. A WIND ADVISORY REMAINS IN EFFECT THROUGH THIS
AFTERNOON DUE TO STRONG WINDS FROM THIS INCREASED PRESSURE
GRADIENT AND STRONG PRESSURE RISES, WITH CURRENT OBSERVED WIND
GUSTS GENERALLY AROUND 45 MPH. BLENDED IN LATEST OBS BUT NO
MAJOR CHANGES TO THE FORECAST WITH THIS UPDATE.
UPDATE
ISSUED AT 555 AM CST TUE DEC 16 2025
WINDS ARE JUST NOW STARTING TO INCREASE ACROSS THE WEST TO NEAR
ADVISORY LEVEL. THE WIND ADVISORY CONTINUES AS PLANNED TODAY BUT
IT WAS UPDATED TO 55 MPH WINDS INSTEAD OF 45 MPH.
DISCUSSION
ISSUED AT 440 AM CST TUE DEC 16 2025
CURRENTLY ZONAL FLOW STRAIGHT FROM THE PACIFIC OCEAN IS PRESENT
ACROSS THE NORTHERN PLAINS. THIS, ALONG WITH A WARM FRONT IS
KEEPING TEMPERATURES VERY MILD OVERNIGHT. AT THE SURFACE A
ALBERTA CLIPPER IS PASSING BY THE STATE, STAYING IN SOUTHERN
CANADA. A TRAILING COLD FRONT OFF THIS LOW WILL MOVE THROUGH
NORTH DAKOTA THIS MORNING. BEHIND IT, STRONG PRESSURE RISES AND
COLD AIR ADVECTION (CAA) WILL MOVE IN, CREATING STRONG WEST
WINDS. THESE WINDS WILL GUST UP TO 55 MPH THIS MORNING AND
AFTERNOON. THIS IS WHAT THE ON GOING WIND ADVISORY IS FOR. THE
ADVISORY HAS BEEN UPDATED TO INCLUDED THE 55 MPH WORDING AS THE
PRESSURE RISES ARE STRONGER THAN BEFORE.
AFTER TODAY, OUR ATTENTION THEN MOVES TO THE POSSIBLE DECEMBER RECORD
BREAKING LOW PRESSURE SYSTEM WEDNESDAY THROUGH THURSDAY. A VERY
STRONG LOW WILL FORM IN SOUTHERN CANADA AGAIN, AIMED AT NORTH
DAKOTA. MODELS ARE ACTUALLY IN DISAGREEMENT WHERE THE CENTER OF
THE LOW WILL GO. MANY HAVE IT MOVING THROUGH THE STATE, BUT SOME
OF THE HI-RES MODELS HAVE THE CENTER STAYING IN SOUTHERN
CANADA, THEN DIPPING INTO NORTHERN MINNESOTA.
WINDS:
WINDS WILL START SOUTHERNLY IN THE WARM SECTOR OF THE SURFACE
LOW, THEN TURN NORTHWEST AS THE FIRST PUSH OF WINDS START. THIS
IS WHEN THE COLD FRONT SWEEPS INTO THE WEST SOMETIME BETWEEN 21Z
AND 00Z WEDNESDAY EVENING. THIS WEAKER PUSH WITH SOME PRESSURE
RISES ON THE BACKSIDE OF THE FRONT, WILL CREATE WIND GUSTS
AROUND 55 MPH TO START. THIS PUSH WILL MOVE WEST TO EAST
THROUGH THE STATE IN THE EVENING. AROUND MIDNIGHT THE BACKSIDE
OF THE LOW WILL HIT WESTERN NORTH DAKOTA LIKE A FREIGHT TRAIN.
VERY COLD AIR WITH EXTREME PRESSURE RISES AND A VERY TIGHT
PRESSURE GRADIENT FORCE WILL SURGE WINDS UP TO 65-70 MPH. THE
HIGHEST WINDS LOOK TO BE IN THE WEST AND SOUTHWEST RIGHT NOW.
SOME MODELS SOUNDINGS HAVE THE TOP OF THE MIXING LAYER REACHING
NEAR 80KTS OF WIND TO MIX DOWN IN THE SOUTHWEST PART OF THE
STATE. THAT SEEMS A LITTLE EXTREME BUT IT IS SOMETHING TO WATCH,
AND SORT OF FITS THE "POSSIBLE DECEMBER RECORD LOW PRESSURE"
VIBE. THE EFI WIND GUST VALUES ARE AT A CLIMATOLOGICALLY MAX
WITH VALUES OF 0.95 TO 1.00. THIS IS A VERY RARE EVENT ACCORDING
TO THAT, AND IF THE LOW DOES SET THE DECEMBER LOW PRESSURE
RECORD, THEN THAT MAKES SENSE. THE HIGHER PRESSURE ON THE
BACKSIDE OF THE SYSTEM WILL CALM WINDS ACROSS THE STATE AFTER
21Z THURSDAY. A HIGH WIND WATCH IS IN EFFECT FOR THIS TIMEFRAME,
AND WILL BE UPGRADED TO A WARNING WHEN WE GET CLOSER.
PRECIPITATION:
FREEZING RAIN WILL BE THE MAIN P-TYPE WEDNESDAY MORNING IN THE
NORTHWEST. THE WARM AIR ALOFT FROM THE ZONAL FLOW, BUT SURFACE
TEMPERATURES BELOW ZERO TO START, WILL CREATE AREAS OF FREEZING
RAIN. LATE WEDNESDAY MORNING THE SURFACE TEMPERATURES SHOULD
WARM ENOUGH TO CHANGE THIS TO RAIN. RAIN ACROSS MOST OF THE
STATE WILL BE LIKELY (60%) BY NOON CST. STARTING AROUND 21Z
THAT COLD FRONT WILL START TO SWITCH THE RAIN TO SNOW WEST TO
EAST ACROSS THE STATE. THE NORTH CENTRAL WILL HAVE THE LONGEST
RESIDENCE TIME IN THE SNOW. OUR CURRENT FORECAST THERE HAS 2 TO
4 INCHES, AND LESS THAN 1 INCH ELSEWHERE. THE NBM PROBABILITIES
OF 4 INCHES IN THE NORTH ARE AROUND 30 PERCENT, BUT FOR 2 INCHES
THAT INCREASES TO 50 TO 70 PERCENT. AS YOU WOULD IMAGINE
FALLING SNOW WITH VERY STRONG WINDS WILL LIKELY CREATE BLIZZARD
CONDITIONS. WE HAVE ISSUED A WINTER STORM WATCH FOR BLIZZARD
CONDITIONS IN THE NORTH CENTRAL FROM WEDNESDAY EVENING THROUGH
THURSDAY MORNING. SNOW SQUALLS ARE ALSO POSSIBLE. THE PARAMETER
CONTINUES TO PEG THE SOUTHWEST CORNER FOR THE HIGHEST CHANCE WEDNESDAY
EVENING WITH THE WRAP AROUND PUSH OF SNOW.
TEMPERATURES:
TEMPERATURES THROUGH THIS EVENT WILL CHANGE A LOT. AHEAD OF THE
SYSTEM WEDNESDAY'S HIGHS WILL BE THE UPPER 30S TO UPPER 40S.
THEN VERY COLD ARCTIC AIR ON THE BACKSIDE OF THE LOW WILL
QUICKLY PLUMMET TEMPS AFTER MIDNIGHT. LOWS THURSDAY MORNING
ACROSS THE NORTH WILL BE 10 BELOW ZERO WITH DANGEROUS WIND
CHILLS NEARING 35 BELOW. TEMPERATURES THURSDAY WILL ONLY RECOVER
TO AROUND ZERO IN THE NORTH, AND 10 ABOVE ELSEWHERE. THE
SOUTHWEST WILL OF COURSE BE WARMER IN THE 20S WITH CHINOOK
WINDS BACK WITH ZONAL FLOW.
THE REST OF THE WEEK ZONAL FLOW WITH ANOTHER CLIPPER IS
FORECAST. THIS CLIPPER WOULD BRING MORE SNOW FRIDAY INTO
SATURDAY AND KEEP TEMPERATURES COLDER THAN NORMAL. BREEZY WINDS
ARE ALSO POSSIBLE WITH THIS CLIPPER TOO. AS OF NOW, THE ONLY
SNOW ACCUMULATIONS WOULD BE AROUND 1 INCH IN THE NORTH CENTRAL.
THROUGH THE WEEKEND AND INTO EARLY NEXT WEEK A LARGE WEAK RIDGE
COULD DEVELOP AND MAINTAIN NEAR NORMAL TEMPERATURES.
TEMPERATURES SPREADS ARE VERY LARGE IN THE NBM TO REFLECT
UNCERTAINTY IN THE MODELS.
AVIATION /12Z TAFS THROUGH 12Z WEDNESDAY/
ISSUED AT 555 AM CST TUE DEC 16 2025
VFR CIGS AND VIS THROUGH THE PERIOD WITH STRONG WIND SHEAR THIS
MORNING. THIS AFTERNOON WEST WINDS WILL GUST NEAR 45KTS BUT THE
WIND SHEAR WILL STOP. AFTER SUNSET WINDS WILL CALM DOWN TO 10KTS
FROM THE SOUTH.
BIS WATCHES/WARNINGS/ADVISORIES
WIND ADVISORY UNTIL 6 PM CST /5 PM MST/ THIS EVENING FOR
NDZ001>005-009>013-017>023-025-035>037-047-048-050-051.
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...JONES
DISCUSSION...SMITH
AVIATION...SMITH
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