854
FXUS63 KMPX 090549
AFDMPX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN
1149 PM CST WED JAN 8 2025
KEY MESSAGES
- LIGHT SNOW WILL MOVE FROM WEST TO EAST ACROSS THE AREA
THURSDAY. MOST AREAS WILL SEE LESS THAN AN INCH OF SNOW,
HOWEVER SLICK SPOTS ARE POSSIBLE.
- CLIPPER SYSTEM TO BRING ANOTHER CHANCE FOR SNOW OVER THE
WEEKEND. CONFIDENCE IN INCREASING IN THE POTENTIAL FOR A FEW
INCHES OF ACCUMULATING SNOW, THOUGH TIMING IS STILL
UNCERTAIN.
DISCUSSION
ISSUED AT 219 PM CST WED JAN 8 2025
SUNSHINE AND TEMPERATURES IN THE TEENS ARE THE THEME ACROSS MOST OF
SOUTH CENTRAL MINNESOTA AND WESTERN WISCONSIN THIS AFTERNOON. THE
ONLY DIFFERENCE IN SKY COVER IS CAPTURED ON SATELLITE ACROSS CENTRAL
MINNESOTA, WHERE AN AREA OF STRATUS IS SLOWLY MEANDERING EAST FROM
ROUGHLY AXN TOWARDS STC (AND LOCATIONS TO THE NORTH). THE FORECAST
WILL REMAIN DRY TONIGHT, WITH THE UPPER RIDGE AXIS POSITIONED
ABOVE THE UPPER MIDWEST. WATER VAPOR IMAGERY SHOWS ASCENT
ACROSS SOUTHERN SASKATCHEWAN AND NORTHERN MONTANA, ASSOCIATED
WITH AN EASTWARD MOVING WAVE THAT WILL BRING THE CHANCE FOR
LIGHT SNOW ON THURSDAY. HIGH CLOUDS WILL BUILD AHEAD OF THIS
FEATURE, WHICH WILL COMBINE WITH LIGHT SOUTHERLY FLOW TO PREVENT
MOST AREAS FROM FALLING BELOW THE DOUBLE DIGITS TONIGHT.
THE AFOREMENTIONED WAVE IS PROGGED TO SLIDE EAST ACROSS THE DAKOTAS
TONIGHT AND WILL SEND A SURFACE COLD FRONT FROM WEST TO EAST ACROSS
MINNESOTA/WISCONSIN TOMORROW. WE ARE EXPECTING A "HIGH POP/LOW
QPF" PRECIPITATION SCENARIO, WHERE MAY LOCATIONS SEE SNOWFLAKES
FLY, HOWEVER POOR MOISTURE (A FEW HUNDREDTHS) AND STANDARD SLR'S
(~12:1) CAP SNOWFALL BELOW AN INCH FOR MOST COMMUNITIES. THE
HIGHEST AMOUNTS (SAY AN INCH AND A HALF IN ISOLATED SETTINGS)
APPEAR TO BE ALONG AND NORTH OF I-94 IN MINNESOTA, WHICH WILL BE
TIED TO BETTER FORCING ALOFT. NONETHELESS, FORECAST SOUNDINGS
DO CAPTURE A FEW HOURS OF DEEPER SATURATION IN TANDEM WITH
SUFFICIENT OMEGA FORCING TO PRODUCE LIGHT SNOW ACROSS MUCH OF
THE AREA. GIVEN HIGH CONFIDENCE LIGHT SNOW AND MINOR ACCUMULATIONS,
WE COLLABORATED WITH NEIGHBORING OFFICES TO BOOST POPS INTO THE
~60-80% RANGE ACROSS WEST CENTRAL MINNESOTA, WHERE HOURLY
PRECIPITATION >0.01" PROBABILITIES ARE THE HIGHEST PER THE 12Z
HREF. WHILE THIS WILL NOT BE A MAJOR SNOWFALL, THE INTRODUCTION
OF EVEN A HALF TO QUARTER INCH OF SNOW MAY BE ENOUGH TO PRODUCE
SLICK SPOTS THURSDAY AFTERNOON & EVENING. A FEW SNOWFLAKES MAY
LINGER AMID THE NORTHWEST FLOW ON FRIDAY MORNING, BEFORE THE
SOUTHWARD MOVEMENT OF 1020S CANADIAN HIGH PRESSURE RESULTS IN A
BRIEF PERIOD OF QUIET WEATHER FRIDAY AFTERNOON-SATURDAY
MORNING.
A POTENT CLIPPER, ORIGINATING ACROSS NORTHERN ALBERTA, IS PROGGED TO
DIVE SOUTHEAST ACROSS THE DAKOTAS SATURDAY MORNING. GUIDANCE DEPICTS
THE ~1002-1004MB LOW MOVING SOUTHEAST OUT OF THE DAKOTAS INTO
MINNESOTA/WISCONSIN SATURDAY EVENING THROUGH SUNDAY MORNING.
THE COMPACT CLIPPER IS SET TO PIVOT OVER SOUTHERN MN/NORTHERN
IA, BEFORE LIFTING TO THE NORTHEAST TOWARDS EASTERN WISCONSIN
(TOWARDS THE REGION OF WARM ADVECTION). THE TRACK OF THE
CLIPPER WILL FOLLOW THE THERMAL GRADIENT, SUCH THAT THERE WILL
LIKELY BE ADDITIONAL SUPPORT FOR PRECIPITATION FROM FRONTOGENIC
FORCING. LATEST GUIDANCE HAS TRENDED UPWARD WITH QPF, WITH
ENSEMBLE MEANS SUGGESTING A WIDE SWATH OF ~0.1" LIQUID
PRECIPITATION. A VARIETY OF INDIVIDUAL ENSEMBLE MEMBERS AND
DETERMINISTIC COUNTERPARTS HAVE TRENDED WETTER, WITH PERHAPS
UPWARDS OF ~0.2" OF QPF. THAT'S PLENTY OF MOISTURE TO WORK WITH
FOR THIS TIME OF YEAR, ESPECIALLY GIVEN THE EXPECTED HIGHER
RATIO NATURE OF THESE CLIPPER EVENTS (SLR'S BETWEEN 15-18:1 PER
THE LATEST NBM AND CONCEPTUALLY COULD BE HIGHER). FOR THIS
REASON, CONFIDENCE IS INCREASING IN WIDESPREAD ACCUMULATING SNOW
OVER THE WEEKEND. WE'LL HAVE TO FINE TUNE THE DETAILS OVER THE
COMING DAYS, AS TIMING AND DURATION OF SNOWFALL REMAIN IN FLUX,
BUT THE LARGE SCALE PIECES ARE POINTING IN A MORE LIKELY DIRECTION
FOR A FEW INCHES OF SNOW. FOR THIS REASON, WE COLLABORATED WITH
NEIGHBORING OFFICES TO BOOST QPF THROUGH 18Z SUNDAY, TO REFLECT
VALUES CLOSER TO THE ENSEMBLE MEAN REFERENCED ABOVE. ADDITIONALLY,
WE BOOSTED POPS SATURDAY NIGHT/SUNDAY MORNING, SO THE GRIDS NOW
FEATURE 40-50% POPS AT ALL FORECAST POINTS.
THE FORECAST DRIES OUT EARLY NEXT WEEK, FOLLOWING THE DEPARTING
LOW. COLD ADVECTION ACROSS THE UPPER MIDWEST WILL WORK TO DROP
TEMPERATURES INTO THE SINGLE DIGITS FOR HIGHS MONDAY/TUESDAY,
ALONG WITH THE POTENTIAL FOR SUB-ZERO LOWS. FACTOR IN WHAT MAY
END UP BEING A FRESH LAYER OF SNOW AND THESE VALUES COULD END UP
EVEN COLDER AS WE APPROACH THE END OF THE FORECAST PERIOD.
AVIATION /06Z TAFS THROUGH 06Z FRIDAY/
ISSUED AT 1141 PM CST WED JAN 8 2025
VFR CONDITIONS WITH SOUTHERLY WINDS WILL HOLD UNTIL ABOUT 12Z
AS A COLD FRONT APPROACHES FROM THE WEST. THIS FRONT WILL BRING
MVFR CIGS/VIS WITH A QUICK HIT OF LIGHT SNOW AND A WIND SHIFT TO
THE NORTHWEST THROUGH THE DAY. BRIEF BOUTS OF IFR CIGS/VIS ARE
POSSIBLE WITH HEAVIER SNOW SHOWERS. ONCE THE FRONT HAS PASSED,
MVFR CIGS WILL PERSIST. FORECAST SOUNDINGS SUGGEST THAT SOME
ADDITIONAL FLURRIES/LIGHT SNOW WILL BE POSSIBLE AFTER 00Z. WINDS
BEHIND THE FRONT COULD GUST TO AROUND 20KTS ACROSS WESTERN
MINNESOTA.
KMSP...TIMING FOR SNOW STILL LOOKS TO BE ON TRACK FROM ROUGHLY
19Z-22Z. AS MENTIONED ABOVE, SOME ADDITIONAL LIGHT SNOW IS
POSSIBLE AFTER 03Z, BUT CONDITIONS SHOULD REMAIN VFR.
/OUTLOOK FOR KMSP/
FRI...MVFR EARLY, THEN VFR. WIND NW 5-10KTS.
SAT...VFR. IFR/SN LIKELY OVERNIGHT. WIND S 5-10KTS.
SUN...MVFR/IFR/SN LIKELY IN MRNG. WIND NW 10-15G25KTS.
MPX WATCHES/WARNINGS/ADVISORIES
MN...NONE.
WI...NONE.
DISCUSSION...STRUS
AVIATION...DYE
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