773
FXUS63 KMPX 211127
AFDMPX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN
527 AM CST SUN DEC 21 2025
KEY MESSAGES
- CHANCE OF WINTRY MIX LATE THIS EVENING INTO MONDAY MORNING.
MINOR ICE AND SNOW ACCUMULATIONS ARE POSSIBLE.
- MILD TEMPERATURES AND WEAK DISTURBANCES WITH LOW
PREDICTABILITY ARE IN STORE OVER THE NEXT 7 DAYS.
DISCUSSION
ISSUED AT 329 AM CST SUN DEC 21 2025
IT'S A COLD START TODAY AS WE WELCOME THE FIRST DAY OF THE WINTER
SOLSTICE. THE GOOD NEWS IS THAT WE'LL BEGIN TO GAIN DAYLIGHT FOR THE
NEXT 6 MONTHS! CURRENT TEMPERATURES ARE IN THE SINGLE DIGITS GIVEN
LIGHT WINDS AND MOSTLY CLEAR SKIES. A BAND OF STRATUS HAS MOVED INTO
CENTRAL MINNESOTA AND THAT HAS ALLOWED TEMPERATURES TO "RECOVER"
FROM THE SUB-ZERO VALUES A FEW HOURS EARLIER. THIS HIGH PRESSURE
WILL SHIFT EAST TO THE SOUTHERN GREAT LAKES TODAY WITH RETURN FLOW
USHERING IN WARMER AIR THAT'LL BE HERE TO STAY THROUGH THE CHRISTMAS
HOLIDAY. CLOUD COVER WILL INCREASE LATE THIS AFTERNOON AND EVENING
AS A LOW PRESSURE MOVES INTO THE ROCKIES. THE WARM AIR ADVECTION
WILL RAMP UP ACROSS THE PLAINS INTO THE UPPER MIDWEST THIS EVENING
AND WILL TRIGGER PRECIPITATION TO DEVELOP ACROSS E SD & SW MN. THE
PRIMARY FORCING MECHANISM FOR THIS PRECIPITATION WILL BE THE
ISENTROPIC UPGLIDE MENTIONED ABOVE. THIS PROCESS IS WHEN WARM/MOIST
IS FORCED TO RISE AS IT TRAVELS ALONG A SLOPING SURFACE OF POTENTIAL
TEMPERATURE OVER THE COLDER SURFACE AND RESULTS IN PRECIPITATION.
WHILE PRECIPITATION LIKELY BEGINS WITHIN THE NEXT 18 TO 24 HOURS,
THERE REMAINS A FEW AREAS OF UNCERTAINTY IN THE FORECAST. FIRST
THERE IS A VARYING AMOUNT OF ISENTROPIC LIFT ACROSS VARIOUS WEATHER
MODELS THAT GO FROM A VERY LIGHT PRECIPITATION EVENT WITH QPF OF A
FEW HUNDREDTHS AT BEST TO OVER A HALF INCH OF QPF IN THE
NAM/NAMNEST. THERE IS STILL A SPREAD BETWEEN 0.02" TO 0.20" EVEN IF
YOU REMOVE THE NAM SUITE. THAT COULD BE THE DIFFERENCE BETWEEN A NON-
EVENT AND AN IMPACTFUL WINTER SYSTEM. THE NEXT UNCERTAINTY IS THE
PRECIPITATION TYPE. THIS BROAD WARM AIR ADVECTION WILL RESULT IN A
WARM NOSE BETWEEN THE DGZ & SURFACE. GUIDANCE VARIES ON HOW WARM
THAT LAYER WILL BE THAT COULD BE THE DIFFERENCE BETWEEN
PREDOMINANTLY SNOW VERSUS FREEZING RAIN. IT ALSO VARIES ON HOW DRY
THAT LAYER IS PRIOR TO SATURATION. DRIER LAYER WOULD LEAD TO COOLER
TEMPERATURES IN THE COLUMN, BUT WE'D LIKELY LOSE SOME QPF POTENTIAL
GIVEN MORE OF IT WOULD BE SACRIFICED TO EVAPORATION ALOFT. WE HAVE
OPTED TO MAINTAIN THE GENERAL IDEA FROM THE PREVIOUS FORECAST.
SURFACE TEMPERATURES SHOULD BE ABOVE FREEZING ACROSS SW MN THAT WILL
RESULT IN PRIMARILY RAIN. AS THE PRECIPITATION MOVES EAST IT WILL
ENCOUNTER COOLER & DRIER AIR THAT WILL RESULT IN ADDITIONAL COOLING
AS TEMPERATURES GO TOWARDS THE WETBULB TEMP. THERE IS A GOOD
POSSIBILITY OF THE COLUMN REMAINING AT OR BELOW FREEZING AND RESULT
IN MOSTLY SNOW ACROSS EASTERN MINNESOTA. THE WAA WILL CAUSE OUR P-
TYPE TO SHIFT TO A WINTRY MIX WITH FREEZING RAIN AND/OR SLEET MIXING
IN ON THE BACK SIDE OF THE PRECIPITATION SHIELD ACROSS EASTERN &
CENTRAL MN. SNOW SHOULD BE THE DOMINANT P-TYPE AS PRECIP MOVES INTO
WESTERN WISCONSIN SO THERE IS HIGHER CONFIDENCE ON THE P-
TYPE FOR W WI.
FOR MINNESOTA: QPF WILL BE GENERALLY A FEW HUNDREDTHS TO A TENTH OF
AN INCH. THIS WILL SUPPORT A HALF INCH TO AN INCH OF SNOW ACROSS
PORTIONS OF CENTRAL & EASTERN MN. SNOW TO LIQUID RATIOS WILL NOT BE
PARTICULARLY IMPRESSIVE AT OR BELOW 10:1. IT'S IMPORTANT TO NOTE
THAT WE'VE OPTED FOR A CONSSHORT HEAVY BLEND AS THE NBM VALUES ARE
FAR TOO LOW (3:1 OR LESS) AND THAT DOESN'T MAKE SENSE CONCEPTUALLY.
LIGHT FREEZING RAIN & SLEET MAY LEAD TO A GLAZE OF ICE AS WELL.
FOR WESTERN WISCONSIN: QPF WILL BE AROUND A TENTH OF AN INCH AND
LEAD TO AROUND AN INCH OF NEW SNOW... BUT IF A STRONGER FORCED
SOLUTION VERIFIES, WE COULD SEE QPF VALUES INCREASE UP TO TWO TENTHS
TO A QUARTER OF AN INCH. SNOW TOTALS WOULD INCREASE AS WELL WITH 1
TO 3" ON THE TABLE AS THE HIGH-END POTENTIAL SOLUTION.
THIS SYSTEM SHOULD NOT BE A PARTICULARLY HIGH IMPACT EVENT, BUT ANY
WINTRY PRECIPITATION FALLING AHEAD OF A MONDAY MORNING COMMUTE CAN
LEAD TO POTENTIAL TRAVEL DELAYS SO PLEASE PLAN AHEAD!
THE WEEK AHEAD WILL BE DOMINATED BY AN IMPRESSIVE MID LEVEL RIDGE
THAT BUILDS IN OVER THE NORTHERN GULF COAST. THIS PATTERN LIKELY
HAS SOME STAYING POWER THROUGH THE END OF THE MONTH. THE RIDGE
WILL LEAD TO MILD AND DRY CONDITIONS ACROSS MUCH OF THE CENTER
OF THE COUNTRY THIS WEEK. OUR THAW PEAKS ON CHRISTMAS DAY ACROSS
THE UPPER MIDWEST. THERE IS UNCERTAINTY OF HOW WARM IT ACTUALLY
GETS AT THE SURFACE ON CHRISTMAS DAY GIVEN THE SIGNIFICANT WARM
ANOMALY AT 850 MB. ANY LINGERING SNOW WOULD HELP MODERATE HOW
MUCH WE CAN WARM AT THE SURFACE. I WOULD EXPECT HIGHS IN THE 40S
UNLESS WE'RE ABLE TO HANG ONTO SOME SNOWPACK THROUGH CHRISTMAS
DAY. LOCATIONS WITHOUT ANY SNOWPACK WILL LIKELY SEE HIGHS IN THE
UPPER 40S AND MAYBE LOW 50S. THIS WILL MARK A THIRD CONSECUTIVE
CHRISTMAS WITH TEMPERATURES WELL ABOVE NORMAL - NOT VERY FESTIVE
IS IT? OTHERWISE, THE PATTERN IS CONTROLLED BY THE MID LEVEL
RIDGE WITH THE EXCEPTION OF WEAK DISTURBANCES EMBEDDED IN THE
FLOW ACROSS THE NORTHERN CONUS. WHY ARE THESE IMPORTANT? WELL
THESE FEATURES AREN'T HANDLED WELL BY NWP UNTIL WE'RE ABLE TO
SAMPLE THEM UPSTREAM. IF ONE OF THESE COME IN STRONGER, IT COULD
LEAD TO BETTER CHANCE OF PRECIPITATION & POSSIBLY A BRIEF
COOLDOWN SIMILAR TO WHAT HAPPENED YESTERDAY. THAT'S WHY THERE
IS LESS CONFIDENCE IN THE LONG RANGE FORECAST THAN NORMAL...
HAPPY WINTER SOLSTICE EVERYBODY.
AVIATION /12Z TAFS THROUGH 12Z MONDAY/
ISSUED AT 527 AM CST SUN DEC 21 2025
VFR WITH LIGHT TO CALM WINDS TO START THIS PERIOD. WINDS WILL
PICK UP FROM THE SOUTH TODAY IN THE 5 TO 10 KNOT RANGE WITH
INCREASING COVERAGE LEADING TO CEILING FORMING. THESE CEILINGS
WILL MOST LIKELY REMAIN VFR. LATE TONIGHT SNOW WILL MOVE IN, BUT
WITH UNCERTAIN COVERAGE. SO KEPT MOSTLY PROB GROUPS IN TAFS FOR
NOW. MINNESOTA TERMINALS COULD ALSO SEE SOME FREEZING RAIN MIX
IN, BUT THE PRIMARY PRECIPITATION TYPE RIGHT NOW LOOKS LIKE IT
WILL BE SNOW. FOR WISCONSIN TERMINALS IT SHOULD REMAIN SNOW
THROUGHOUT AND CONFIDENCE IN MORE WIDESPREAD SNOW IS HIGHER.
KMSP...VFR AND LIGHT WINDS OVERALL THIS PERIOD, BUT STILL
SEEING A CHANCE FOR SOME LIGHT WINTRY PRECIPITATION TONIGHT. FOR
MSP IT LOOKS LIKE IT WOULD FALL BEFORE THE MORNING RUSH AND
WOULD BE LIGHT WITH OUR CURRENT FORECAST CALLING FOR 0.1" OF
SNOW ACCUMULATION. RECENT TRENDS HAVE BEEN TRENDING LATER
THOUGH, SO THIS COULD SLIP INTO THE EARLY PART OF THE MORNING
RUSH.
/OUTLOOK FOR KMSP/
MON PM...VFR. WIND S 5-10KTS.
TUE...VFR. WIND NW 5-10KTS.
WED...VFR. WIND SE 5-10KTS.
MPX WATCHES/WARNINGS/ADVISORIES
MN...NONE.
WI...NONE.
DISCUSSION...BPH
AVIATION...NDC
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