059
FXUS63 KBIS 241525
AFDBIS
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BISMARCK ND
925 AM CST WED DEC 24 2025
KEY MESSAGES
- FOG MAY RETURN AGAIN THIS EVENING THROUGH CHRISTMAS MORNING.
- A LARGE TEMPERATURE GRADIENT REMAINS ACROSS THE AREA WITH
HIGHS THROUGH FRIDAY GENERALLY NEAR TO BELOW AVERAGE NORTH AND
EAST OF THE MISSOURI RIVER (TEENS AND 20S) TO ABOVE AVERAGE
SOUTH AND WEST OF THE RIVER (30S AND 40S).
- 20 TO 30 PERCENT CHANCE OF LIGHT MIXED PRECIPITATION ON
CHRISTMAS DAY, MAINLY NORTH AND EAST.
UPDATE
ISSUED AT 921 AM CST WED DEC 24 2025
SKY COVER WAS MODIFIED TO BETTER REFLECT CURRENT SATELLITE
IMAGERY AND TRENDS THIS MORNING. OTHERWISE, THE FORECAST REMAINS
IN GOOD SHAPE FOR TODAY.
QUASI-ZONAL FLOW ALOFT WITH BROAD UPPER LEVEL RIDGING ACROSS THE
US. THIS RESULTS IN QUIET WEATHER FOR TODAY, WITH HIGHS SIMILAR
TO SLIGHTLY WARMER TODAY COMPARED TO YESTERDAY.
UPDATE
ISSUED AT 559 AM CST WED DEC 24 2025
PATCHY FOG REMAINS ACROSS MOST OF THE FORECAST AREA. HOWEVER, IT
HAS BEEN UNABLE TO MATERIALIZE INTO ANYTHING IMPACTFUL WITH
VISIBILITY AT ALL SITES PRESENTLY 6 SM OR GREATER. WIDESPREAD
HIGH CLOUDS AND OTHER FACTORS MENTIONED IN THE FULL DISCUSSION
MAY LIMIT FURTHER DETERIORATION ACROSS THE FORECAST AREA THIS
MORNING. HOWEVER, IT WILL BE INTERESTING TO SEE IF MORE
IMPACTFUL FOG DEVELOPS AS THE SUN RISES, ESPECIALLY IN AREAS
WITH CLEAR SKIES.
DISCUSSION
ISSUED AT 323 AM CST WED DEC 24 2025
THERE ARE TWO MAIN FORECAST CHALLENGES FOR TODAY THROUGH
CHRISTMAS NIGHT. THE FIRST IS THE POTENTIAL FOR WIDESPREAD DENSE
FOG. THE SECOND IS FOR LIGHT MIXED PRECIPITATION ON CHRISTMAS
DAY. THE BOTTOM LINES UP FRONT TO THE NEXT FEW PARAGRAPHS OF
THIS DISCUSSION ARE THAT NO MAJOR WINTER WEATHER SYSTEMS ARE
EXPECTED FOR THE CHRISTMAS HOLIDAY. HOWEVER, THERE IS A GREATER
THAN ZERO CHANCE OF AT LEAST SOME IMPACTFUL WEATHER AT TIMES.
IN REGARD TO FOG, VARIOUS LOCATIONS ARE CURRENTLY REPORTING
REDUCED VISIBILITY, THOUGH STILL MOSTLY IN EXCESS OF 5 SM.
OVERALL, HI-RES MODELS HAVE GREATLY BACKED OFF ON DENSE FOG FOR
THIS MORNING AND TODAY COMPARED TO YESTERDAY. THIS ISN'T TOO
SURPRISING AS THE SET-UP DIDN'T SEEM OVERLY FAVORABLE. FOR ONE,
NEAR-SURFACE WINDS ARE PROGGED TO REMAIN IN EXCESS OF 20 KTS
THROUGH MOST OF THE EARLY MORNING, THOUGH PERHAPS WEAKENING
TOWARDS MID-MORNING. SECOND, CLOUD COVER IS PRESENT ACROSS MOST
OF THE STATE. THIRD, DESPITE SOUTHEASTERLY FLOW ACROSS PARTS OF
THE AREA EARLY THIS MORNING, WINDS ARE SHIFTING TO A MORE
NORTHERLY (AND UNFAVORABLE) DIRECTION. FINALLY, DESPITE MOISTURE
ADVECTION IN THE LOWER LEVELS, THERE HASN'T BEEN ANY IMPACTFUL
SNOWMELT TO HELP SATURATE THE SURFACE LAYER. IN AREAS WHERE
TEMPERATURES REACHED THE MID 30S TO LOW 40S YESTERDAY, THERE IS
NO SNOW. IN AREAS WHERE SNOW IS PRESENT, TEMPERATURES DIDN'T GET
ABOVE FREEZING.
IN REGARD TO TONIGHT THROUGH CHRISTMAS DAY, SOME HI-RES MODELS
REMAIN QUITE AGGRESSIVE IN FOG DEVELOPMENT. HOWEVER, THERE
REMAIN INHIBITORS HERE AS WELL. FIRST, MODELS ARE A BIT SLOWER
IN HIGH PRESSURE PROPAGATING ACROSS SOUTHERN CANADA THAN THEY
HAD BEEN. THIS MEANING THAT SOUTHEASTERLY FLOW AT THE SURFACE
ISN'T PROGGED TO RETURN UNTIL LATER TONIGHT FOR MUCH OF THE
AREA. BUT EVEN WHEN IT DOES, SUSTAINED WINDS ARE MOSTLY AROUND
10 TO 15 KTS WITH GUSTS UP TO 20 KTS. WITHOUT SIGNIFICANT
SNOWPACK MELTING, SUCH AS YOU'D EXPECT MORE IN THE SPRINGTIME,
THESE WINDS SEEM A LITTLE STRONG TO PRODUCE WIDESPREAD ADVECTION
FOG, EVEN WITH SATURATION IN THE LOWER LEVELS. FURTHERMORE,
ONCE AGAIN, NEAR-SURFACE WINDS REMAIN ELEVATED AND GENERALLY IN
EXCESS OF 20 KTS WITH DIRECTIONAL SHEAR. ALL OF THIS FAVORS
LOW-LEVEL STRATUS, PERHAPS WITH AREAS OF 3 TO 5 SM VISIBILITY
REDUCTIONS FROM FOG, OVER WIDESPREAD DENSE FOG. HOWEVER, BOTH
OUTCOMES ARE PLAUSIBLE DEPENDING ON THE ATMOSPHERIC REALITY WHEN
ALL IS SAID AND DONE.
OF NOTE, AS MENTIONED, THERE IS A LOT OF LOW LEVEL MOISTURE
AVAILABLE OFF THE SURFACE. DETERMINISTIC FORECAST SOUNDINGS
FAVOR A SATURATED LAYER THAT APPROACHES, BUT GENERALLY REMAINS
JUST UNDER 1 KM IN DEPTH. THESE SOUNDINGS ALSO SUGGEST
SATURATION MAY APPROACH THE DGZ, ESPECIALLY ALONG AND EAST OF
THE MISSOURI RIVER, AND IN THE NORTH. AS SUCH, SHOULD ANY
PRECIPITATION BE SQUEEZED OUT OF A THEORETICAL LOW-LEVEL STRATUS
DECK, THE EXACT P-TYPE REMAINS IN QUESTION. IT COULD WIND UP IN
THE FORM OF LIGHT FREEZING DRIZZLE, LIGHT SNOW/FLURRIES, OR
SLEET. PERHAPS PERIODS OF A TRUE WINTRY MIX AS WELL. OF NOTE,
NBM POPS HAVE REALLY PULLED BACK IN REGARD TO CHRISTMAS DAY WITH
MOST MENTIONABLE POPS NOW IN THE EVENING FOR THE EASTERN HALF
OF THE STATE, AND MOSTLY NON-MENTIONABLE POPS DURING THE DAY IN
ALL BUT THE SOUTHWEST. THOUGH 20 PERCENT POCKETS REMAIN IN THE
NORTH. OF NOTE, EVEN IF ANY FREEZING RAIN OR DRIZZLE DOES OCCUR
ICE ACCUMULATION PROBABILITIES ARE LOW WITH THE NBM MAINTAINING
10 TO 20 PERCENT CHANCE OF .01 INCH OVER A 24 HOUR PERIOD
(CLOSER TO 10 PERCENT FOR ANY SIX HOUR PERIOD) AND THE HREF FRAM
ENSEMBLE MEAN ONLY PRODUCING VERY ISOLATED POCKETS OF .01 INCH
OF ICE ACCUMULATION.
BEYOND THE HOLIDAY, SHORTWAVE ENERGY COULD BRING LIGHT
PRECIPITATION MAINLY TO NORTHERN NORTH DAKOTA TO FINISH OUT THE
WEEK. AS OF NOW, THIS IS FAVORED TO MOSTLY BE IN THE FORM OF
SNOW. AFTER WHICH, MOSTLY DRY CONDITIONS ARE FAVORED FOR SUNDAY
AND MONDAY WITH LOW CHANCES RETURNING DURING THE MIDDLE OF NEXT
WEEK.
IN REGARD TO TEMPERATURES, THE PATTERN OF COOLER TEMPERATURES
NORTHEAST TO WARMER TEMPERATURES SOUTHWEST IS FAVORED TO
CONTINUE THROUGH THE REMAINDER OF THE WEEK. THE EXCEPTION IS
SATURDAY WHERE THE GRADIENT MAY BE MORE NORTH TO SOUTH. VERY
COLD TEMPERATURES ARE PROGGED TO RETURN ON SUNDAY WITH HIGHS
MOSTLY IN THE SINGLE DIGITS ON EITHER SIDE OF ZERO, EXCEPT A
BIT WARMER AND IN THE LOW TEENS SOUTHWEST. COMBINED WITH WINDY
CONDITIONS, COLD WEATHER HEADLINES MAY WIND UP BEING NECESSARY
WHEN ALL IS SAID AND DONE. OF NOTE, MODELS REALLY HAVE NO IDEA
OF WHAT IS GOING TO HAPPEN NEXT WEEK. FOR EXAMPLE, THERE IS AN
INSANE NBM ENSEMBLE 25TH/75TH TEMPERATURE SPREAD ON NEW YEAR'S
EVE. CURRENTLY IT IS A 40 DEGREE SPREAD FOR HIGH TEMPERATURES IN
BISMARCK FROM 5 BELOW ZERO TO 35 ABOVE ZERO. IN OTHER WORDS, BE
ON THE LOOKOUT FOR THE POSSIBILITY OF A LARGE CHANGE IN THE
DETERMINISTIC FORECAST BEYOND SUNDAY, AND ESPECIALLY ON NEW
YEAR'S EVE.
AVIATION /12Z TAFS THROUGH 12Z THURSDAY/
ISSUED AT 559 AM CST WED DEC 24 2025
PATCHY FOG IS PRESENT ACROSS MUCH OF WESTERN THROUGH CENTRAL ND
THIS MORNING. HOWEVER, VISIBILITY REMAINS AT 6 SM OR GREATER AT
ALL OBSERVATION SITES. FURTHER DETERIORATION IS POSSIBLE THIS
MORNING, ESPECIALLY AS THE SUN BEGINS TO RISE, AND ESPECIALLY
IN AREAS WITH CLEAR SKIES. THAT SAID, MODELS HAVE NOT HANDLED
THIS WELL SO FAR THUS MAINTAINED VFR CONDITIONS IN THE TAFS AT
ALL TERMINALS, EXCEPT KJMS, FOR THIS MORNING. WIDESPREAD FOG
DEVELOPMENT IS POSSIBLE AGAIN TONIGHT, ALTHOUGH ONCE AGAIN THERE
WILL BE LIMITING FACTORS THAT MAY PREVENT IFR/LIFR VISIBILITY
REDUCTIONS. ONE IMPORTANT POINT THOUGH IS THAT UNLIKE THIS
MORNING, EVEN IF IMPACTFUL FOG DOESN'T DEVELOP, IFR/LIFR
CEILINGS ARE LIKELY TO DEVELOP ACROSS ALL OF WESTERN THROUGH
CENTRAL ND TONIGHT AND INTO CHRISTMAS MORNING. OF NOTE, A WINTRY
MIX COULD FALL FROM THIS LOW-LEVEL STRATUS LATE TONIGHT.
HOWEVER, DUE TO A RELATIVELY SHALLOW SATURATED LAYER, CONFIDENCE
IS VERY LOW SO LEFT OUT OF THE FORECAST FOR NOW.
BIS WATCHES/WARNINGS/ADVISORIES
NONE.
UPDATE...NH
DISCUSSION...TELKEN
AVIATION...TELKEN
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