697
FXUS63 KMPX 290558
AFDMPX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN
1258 AM CDT SAT MAR 29 2025
KEY MESSAGES
- WIDESPREAD RAIN DEVELOPS MIDDAY SATURDAY, THEN TRANSITIONS TO
WINTRY MIX AND SNOW SATURDAY NIGHT INTO SUNDAY. SOME SNOW
ACCUMULATION AND ICE ACCRETION LOOKS LIKELY.
- BREEZY CONDITIONS EXPECTED TONIGHT THROUGH SUNDAY NIGHT.
- MUCH COOLER STARTING TOMORROW THROUGH NEXT WEEK, WITH ANOTHER
LARGE-SCALE SYSTEM LIKELY WEDNESDAY-THURSDAY WITH RAIN AND
SNOW.
DISCUSSION
ISSUED AT 345 PM CDT FRI MAR 28 2025
SURFACE ANALYSIS THIS AFTERNOON DEPICTS A COMPACT LOW PRESSURE
CENTER A LITTLE NORTH OF FSD, WITH NEARLY WEST-TO-EAST FRONTAL
ORIENTATION. THE WARM FRONT EXTENDS EAST OVER SOUTHERN MN INTO
FAR SOUTHWESTERN MN, ABLY NOTICED ON SURFACE CHARTS BY THE STARK
TEMPERATURE DIFFERENCE FROM NORTH TO SOUTH ACROSS THE WFO MPX
COVERAGE AREA. TEMPERATURES ARE STILL ONLY IN THE 40S/50S OVER
THE NORTHERN TWO OR SO TIERS OF COUNTIES, WHILE HIGHS HAVE
SURGED INTO THE 70S OVER MUCH OF THE SOUTHERN HALF OF OUR
COVERAGE AREA, WITH FAR SOUTHERN PORTIONS HAVE ALREADY REACHED
THE LOWER 80S. ALOFT, A BROAD RIDGE OVER AND EAST OF THE
MISSISSIPPI RIVER WILL SLIDE EASTWARD, ALLOWING A SHARP LONGWAVE
TROUGH OVER THE ROCKIES TO PUSH INTO THE PLAINS TONIGHT AND
ACROSS THE UPPER-MID MISSISSIPPI RIVER VALLEY REGIONS OVER THE
WEEKEND.
KMPX RADAR SHOWS WEAK RETURNS WELL AWAY FROM THE RADAR,
INDICATING MOISTURE ALOFT BEING PICKED UP BUT SURFACE
OBSERVATIONS ARE CONFIRMING A DEEP DRY LAYER PREVENTING THESE
RETURNS FROM REACHING THE SURFACE. HOWEVER, LOW LEVEL MOISTURE
HAS BEEN ADVECTING NORTHWARD, SOUTH OF THE FRONT, AS EVIDENCED
BY DEWPOINTS REACHING THE MID-UPPER 50S IN FAR SOUTHERN MN.
GOING INTO THE LATE AFTERNOON AND EVENING HOURS, THERE IS STILL
A SMALL CHANCE OF THUNDERSTORMS OVER FAR SOUTHERN MN INTO
WESTERN WI AS THAT LOW-LEVEL MOISTURE ADVECTION CONTINUES WITHIN
THE WARMEST AIR OVER OUR COVERAGE AREA. AS INDICATED
PREVIOUSLY, LAPSE RATES ARE RATHER STEEP, HELPING BUILD MUCAPE
VALUES TO AROUND 1000 J/KG, SUFFICIENT FOR THUNDERSTORM
DEVELOPMENT IN THIS ENVIRONMENT. THUNDERSTORMS THAT FORM IN THIS
REGIME ARE CAPABLE OF PRODUCING LARGE HAIL (1" OR GREATER), BUT
COVERAGE WOULD BE ISOLATED AT BEST. NEVERTHELESS, THE MARGINAL
RISK GOING INTO THIS EVENING IS VALID WITH THE CURRENT SETUP.
FOR TONIGHT, THE AFOREMENTIONED LOW WILL SLIDE ATOP THE TWIN
CITIES METRO AND OVER CENTRAL WI THROUGH THIS EVENING, THEN
INTO MI BY DAYBREAK SATURDAY. THE EXIT OF THIS LOW WILL BRING TO
AN END ANY THREAT FOR THUNDERSTORMS TONIGHT, AND RESULT IN
MAINLY DRY CONDITIONS OVERNIGHT. HOWEVER, THE COLD FRONT OF THIS
SYSTEM WILL BE THRUST TO THE SOUTH, ALLOWING FOR EFFICIENT COLD
AIR ADVECTION THIS EVENING THROUGH TONIGHT WHICH WILL DROP
TEMPERATURES PRETTY STRONGLY OVER MUCH OF THE COVERAGE AREA.
AFTER MUCH OF THE AREA SEES HIGHS TODAY IN THE 60S, 70S AND
LOWER 80S, LOWS TONIGHT WILL RANGE FROM THE LOWER 30S TO LOWER
40S. THESE LOWER TEMPERATURES WILL SET THE STAGE FOR THE COMPLEX
PRECIPITATION EVENT EXPECTED FOR THIS WEEKEND.
A MUCH STRONGER LOW PRESSURE CENTER DEVELOPING OVER THE ROCKIES
TODAY WILL PUSH AWAY FROM CO AND INTO WESTERN KS TONIGHT THROUGH
TOMORROW. A SIGNIFICANT UPTICK IN ISENTROPIC LIFT TO THE NORTH
OF THE ELONGATED STALLED FRONT IN ADVANCE OF THIS DEVELOPING LOW
WILL TAKE GOOD ADVANTAGE OF THE MOISTURE ADVECTED INTO THE
REGION, SPARKING OFF WIDESPREAD RAIN THAT WILL MOVE SOUTH-TO-
NORTH OVER THE REGION DURING THE DAY SATURDAY. THE TRACK OF THIS
LOW STILL LOOKS TO MOVE FROM KS INTO SOUTHERN NE AND ACROSS IA
SATURDAY THROUGH SUNDAY MORNING, KEEPING MN/WI WELL INTO THE
COLDER PORTION OF THIS SYSTEM. WITH HIGHS ONLY TOPPING OUT IN
THE UPPER 30S TO MID 40S, TEMPERATURES ARE EXPECTED TO DROP TO
AND UNDER THE FREEZING MARK SATURDAY EVENING THROUGH LATE
SATURDAY NIGHT. THIS WILL SUPPORT A TRANSITION PERIOD OF RAIN TO
FREEZING RAIN, MAINLY DUE TO THE SURFACE TEMPERATURES COOLING
OFF QUICKER THAN THE LAYERS OF AIR ALOFT WHICH WILL BE QUITE
SATURATED AND WILL COOL BELOW FREEZING AT A SLOWER RATE. THUS,
IT AMOUNTS TO THE DURATION OF SUB-FREEZING SURFACE TEMPERATURES
WHICH WILL DETERMINE THE EXACT AMOUNT OF ICING THAT ANY GIVEN
LOCATION RECEIVES. GIVEN THE FAIRLY CONSISTENT AXIS OF ICING
FROM SW MN TO NORTH OF THE TWIN CITIES AND TOWARDS THE RICE
LAKE-LADYSMITH AREAS, WHICH STILL LOOKS GOOD EVEN AFTER TODAY'S
MODEL RUNS TO HAVE THE HIGHEST ICING THREAT, THIS IS WHERE
AROUND A TENTH OF AN INCH OF ICE ACCRETION LOOKS TO OCCUR. THERE
MAY WELL BE SOME ISOLATED SPOTS THAT RECEIVE MORE THAN THAT,
POTENTIALLY 0.15"- 0.20" ICE, WHILE SOUTH OF THAT LINE MAY SEE
BETWEEN A TRACE AND A TENTH. ONCE THE PRECIPITATION CHANGES OVER
TO SNOW, MAINLY DURING THE EARLY MORNING HOURS SATURDAY THROUGH
THE DAY SUNDAY, AS TEMPERATURES WILL SLOWLY DROP FROM WEST TO
EAST, WET SNOW WILL PERSIST FOR MUCH OF THE DAY SUNDAY. SNOW
ACCUMULATIONS LOOK TO RANGE 2-4" FROM NEAR AND NORTH OF THE ST
CLOUD AREA, WITH UP TO 2" BETWEEN THERE AND THE US212 CORRIDOR,
THEN LESS THAN AN INCH SOUTH OF US212. MUCH OF THE ACCUMULATION
WILL LIKELY BE CONFINED TO GRASSY AREAS, AND ALSO WILL NOT STICK
AROUND DUE TO WARM GROUND TEMPERATURES IN ADVANCE OF THE
SNOWFALL AND HIGHS CLIMBING BACK TO THE UPPER 30S TO AROUND 40
ON MONDAY.
WITH ALL THAT SAID, A WINTER WEATHER ADVISORY HAS BEEN ISSUED
THIS AFTERNOON WHICH COVERS MUCH OF WESTERN, SOUTHWESTERN AND
CENTRAL MN INTO WESTERN WI DUE TO THE POTENTIAL TRAVEL IMPACTS
OF THIS SYSTEM. THERE STILL MAY BE SOME ADJUSTMENTS MADE TO THE
COUNTIES WITHIN THE ADVISORY AND TO THE EXACT AMOUNTS, BUT
CONFIDENCE IS HIGH THAT A STORM SYSTEM IN EARLY SPRING WILL
BRING WINTER WEATHER TRAVEL IMPACTS TO OUR COVERAGE AREA THIS
WEEKEND.
BEHIND THIS SYSTEM, NORTH-SOUTH ORIENTED HIGH PRESSURE WILL
SLIDE ACROSS THE AREA SUNDAY NIGHT THROUGH EARLY TUESDAY,
BRINGING A BRIEF REPRIEVE FROM PRECIPITATION BUT REINFORCING THE
COLD AIR IN PLACE. LOWS WILL STAY IN THE 20S WHILE HIGHS ONLY
RANGE FROM THE MID 30S TO LOWER 40S. ANOTHER POTENT STORM
SYSTEM, ALSO A COLORADO LOW, WILL DEVELOP MONDAY-TUESDAY THEN BE
PICKED UP BY ANOTHER SHARP LONGWAVE WESTERN CONUS TROUGH AND BE
PUSHED ACROSS THE CENTRAL STATES INTO THE UPPER MIDWEST
WEDNESDAY-THURSDAY. THIS SYSTEM ALSO LOOKS TO BE A WIDESPREAD
RAIN-SNOW PRODUCER BUT ONLY LACKING ANY THUNDERSTORM POTENTIAL
GIVEN THE MUCH LOWER TEMPERATURES AND, HENCE, LACK OF
INSTABILITY. BUT, WITH REMAINING ON THE COLD SIDE OF THIS TRACK
AS WELL, THERE IS THE LIKELIHOOD OF BOTH RAIN AND SNOW FOR
PRECIPITATION TYPES. CHANCES FOR ICING PRECIPITATION LOOK MUCH
LESS LIKELY WITH THIS MIDWEEK SYSTEM, SO P-TYPES ARE LIMITED TO
RAIN AND SNOW. BUT, CONSENSUS POPS ARE IN THE 80-90 PERCENT
RANGE SO THERE IS VERY LITTLE QUESTION THAT OUR AREA WILL SEE
MORE PROLONGED PRECIPITATION NEXT WEEK.
AVIATION /06Z TAFS THROUGH 06Z SUNDAY/
ISSUED AT 1244 AM CDT SAT MAR 29 2025
THE THUNDER THREAT IS NOW DONE AT ALL TERMINALS AND WE ARE
FIRMLY ENTRENCHED WITHIN THE COLD SIDE OF ANY FRONTS. GIVEN THE
COLD ADVECTION, WE'VE SEEN STRATUS OVERSPREAD THE AREA AND THIS
STRATUS IS GOING NOWHERE THIS PERIOD. IT WILL LOWER THROUGH THE
NIGHT, THOUGH MAY REBOUND SOME SATURDAY MORNING AHEAD OF THE
WIDESPREAD PRECIPITATION SHIELD THAT WILL OVERSPREAD THE ENTIRE
MPX AREA SATURDAY AFTERNOON. THE MAIN UNCERTAINTY WITH THIS
PRECIP DEALS WITH HOW LONG WILL A TRANSITION FROM RAIN TO SNOW
TAKE, WITH THAT TRANSITION PERIOD BETWEEN THE RAIN AND SNOW
FEATURING A MIX IF SLEET AND FREEZING RAIN. THERE'S LOTS OF
SPREAD IN THE MODELS WITH HOW LONG THIS TRANSITION TAKES, WITH
THE HRRR SHOWING A PRETTY NARROW WINDOW OF MIX BEFORE GOING TO
ALL SNOW, WHILE MODELS LIKE THE NAM SHOW SEVERAL HOURS OF
FZRA AND SLEET BEFORE SNOW BECOMES DOMINATE. FOR NOW, LEANED
HEAVILY ON A RAP TIMING FOR P-TYPE TRANSITIONS, THOUGH FURTHER
REFINEMENTS IN P-TYPE TIMING WILL FOR SURE HAPPEN OVER THE NEXT
COUPLE OF SETS OF TAFS.
KMSP...SOME LIGHT RAIN WILL BE POSSIBLE AS EARLY AS 16Z, THOUGH
WIDESPREAD AND STEADY PRECIP IS EXPECTED TO ENVELOPE MSP AROUND
20Z. AFTER THAT, THE NEXT DIFFICULTY WILL BE TRYING TIME P-TYPE
TRANSITIONS. THERE'S STILL QUITE A BIT OF UNCERTAINTY WITH
THAT, THOUGH MODEL CONSENSUS DOES POINT TO THE GREATEST ICE
THREAT REMAINING JUST NORTH OF MSP.
/OUTLOOK FOR KMSP/
SUN...MVFR/IFR. -SN LIKELY WIND N 10-15G25 KTS.
MON...VFR. WIND N TO NW 5-10 KTS.
TUE...VFR. RASN/MVFR/IFR LATE. WIND SE 10-15G25 KTS.
MPX WATCHES/WARNINGS/ADVISORIES
MN...WINTER WEATHER ADVISORY FROM 7 PM THIS EVENING TO 7 PM CDT
SUNDAY FOR ANOKA-BENTON-BROWN-CARVER-CHIPPEWA-CHISAGO-
DOUGLAS-HENNEPIN-ISANTI-KANABEC-KANDIYOHI-LAC QUI PARLE-
MARTIN-MCLEOD-MEEKER-MILLE LACS-MORRISON-NICOLLET-POPE-
RAMSEY-REDWOOD-RENVILLE-SHERBURNE-SIBLEY-STEARNS-STEVENS-
SWIFT-TODD-WASHINGTON-WATONWAN-WRIGHT-YELLOW MEDICINE.
WI...WINTER WEATHER ADVISORY FROM 7 PM THIS EVENING TO 7 PM CDT
SUNDAY FOR BARRON-POLK-RUSK-ST. CROIX.
DISCUSSION...JPC
AVIATION...MPG
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