278
FXUS63 KMPX 270823
AFDMPX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN
323 AM CDT THU MAR 27 2025
KEY MESSAGES
- 30+ DEGREE TEMPERATURE SPREAD FROM NORTH TO SOUTH FRIDAY AFTERNOON.
HIGHS WILL RANGE BETWEEN THE 40S IN CENTRAL MINNESOTA TO THE
MID 80S IN SOUTHERN MINNESOTA.
- MARGINAL RISK (LEVEL 1/5) FOR SEVERE THUNDERSTORMS FRIDAY EVENING.
LARGE HAIL IS THE PRIMARY THREAT.
- WIDESPREAD PRECIPITATION ARRIVES SATURDAY. RAIN WILL BE THE DOMINANT
P-TYPE, HOWEVER A TRANSITION TO SNOW IS LIKELY. SLUSHY SNOW
ACCUMULATIONS POSSIBLE, ESPECIALLY ACROSS CENTRAL MINNESOTA.
DISCUSSION
ISSUED AT 311 AM CDT THU MAR 27 2025
TODAY...SCATTERED RAIN SHOWERS ARE DEPARTING TO THE SOUTHEAST EARLY
THIS MORNING. IT'S SETTING UP TO BE A NICE THURSDAY, WITH
FILTERED SUNSHINE AND HIGHS IN THE UPPER 50S TO MID 60S.
FORECAST SOUNDINGS INDICATE MIXING THROUGH THE LOWEST ~5K FEET
OF THE COLUMN, WHICH IF REALIZED WILL PROMOTE HIGHS IN THE MID
60S ACROSS MUCH OF SOUTHERN MN. SPEAKING OF WHICH, WILL NEED TO
KEEP AN EYE ON THE AFOREMENTIONED MIXING ACROSS THE EASTERN HALF
OF THE AREA DUE TO LOWERING RH VALUES. OUR LATEST FORECAST
FEATURES MINIMUM RH'S BETWEEN 30 TO 40 PERCENT, BUT ANY OVERACHIEVEMENT
ON THE HIGHS COULD ELEVATE FIRE WEATHER CONCERNS. WITH THAT SAID,
FIRE WEATHER CONDITIONS SHOULD REMAIN RELATIVELY LIMITED DUE TO
OUR FORECAST WINDS OF 5-10 KTS ACROSS THE REGION OF LOWEST
RH'S.
SYNOPSIS...SURFACE LOW PRESSURE IS FORECAST TO DEVELOP OVER THE
DAKOTAS TONIGHT, WITH AN ASSOCIATED WARM FRONT EXTENDING SOUTHEAST
THROUGH IA AND INTO IL. THE NORTHWARD ADVANCE OF THE WARM FRONT
AND SOUTHEASTWARD APPROACH OF THE SURFACE LOW WILL SERVE AS THE
FOCUS FOR TWO ROUNDS OF THUNDERSTORMS, FIRST LATE TONIGHT INTO
EARLY FRIDAY AND THEN AGAIN LATE FRIDAY INTO EARLY SATURDAY. THE
LATTER OF OF THE TWO WHICH FEATURES THE CHANCE FOR STRONG TO
SEVERE THUNDERSTORMS. A NOTABLE TEMPERATURE SCENARIO WILL
DEVELOP BETWEEN THE ROUNDS OF CONVECTIVE ACTIVITY, WITH HIGHS IN
THE 80S POSSIBLE ACROSS SOUTHERN MINNESOTA. LET'S BREAK IT DOWN
BY TIME PERIOD:
TONIGHT - FRIDAY MORNING...GUIDANCE DEPICTS A 45+ KNOT LOW-LEVEL JET
SPANNING THE WARM SECTOR FROM NEBRASKA TO CENTRAL IOWA. THE EAST-
NORTHEAST ORIENTATION OF THE LLJ WILL WORK TO ADVANCE THE WARM FRONT
NORTHWARD TO THE MN/IA STATE BORDER BY DAYBREAK FRIDAY. RAP
ILLUSTRATES A FEW HUNDRED JOULES OF MLCAPE ALONG WITH 7.5-8C/KM
LAPSE RATES ACROSS SOUTHERN MN/WESTERN WI. WHILE CAM GUIDANCE IS NOT
OVERLY EXCITED ABOUT THE AREAL COVERAGE OF THUNDERSTORMS, THESE
NOCTURNAL LLJ SETUPS ARE NOTORIOUS FOR PRODUCING ELEVATED
CONVECTION. WITH THIS IN MIND, WE HAVE INCLUDED 30-40% POPS FOR
THUNDERSTORMS ACROSS SOUTHEASTERN MN/WESTERN WI AFTER MIDNIGHT
THROUGH ABOUT 8 AM OR SO. WOULD NOT ANTICIPATE MUCH IN THE WAY OF A
SEVERE WEATHER RISK, THOUGH HAIL IS PLAUSIBLE GIVEN THE STEEP LAPSE
RATES.
FRIDAY AFTERNOON...BY MIDDAY TOMORROW, ~995MB SURFACE LOW IS
FORECAST TO BE LOCATED NEAR THE SD/MN BORDER. STRONG MID-LEVEL FLOW
WILL AID IN THE ADVANCEMENT OF A HUMID AIRMASS, CHARACTERIZED BY DEW
POINTS IN THE MID TO UPPER 50S SOUTH OF THE WARM FRONT. THE EASTWARD
PROGRESSION OF THE SURFACE LOW WILL CREATE A STRONG BAROCLINIC ZONE
ACROSS SOUTH CENTRAL MN. THE TEMPERATURE SPREAD ACROSS OUR FORECAST
AREA WILL BE VERY IMPRESSIVE, FROM THE 40S IN CENTRAL MINNESOTA TO
THE MID 80S IN SOUTHERN MINNESOTA. THE BIG FORECAST CHALLENGE IS
IDENTIFYING JUST HOW FAR NORTH THE WARM FRONT WILL LIFT. THE NBM HAS
CONTINUED TO "TIGHTEN UP" THE THERMAL GRADIENT NOW THAT WE'RE
ENTERING THE RANGE OF THE HI-RES MODELS. AS A RESULT, WE ARE
ANTICIPATING A SCENARIO THAT FEATURES A 15 TO 20 DEGREE TEMPERATURE
SPREAD FROM NORTH TO SOUTH ACROSS ONE TIER OF COUNTIES. LATEST NBM
PLACES THE GRADIENT THROUGH SWIFT - ANOKA - CHIPPEWA (WI). THIS
SOLUTION PUTS MOST OF THE TWIN CITIES METRO SOUTH OF THE WARM FRONT,
THUS WITH HIGHS IN THE UPPER 70S. IT'S INEVITABLE THAT THE FORECAST
IS GOING TO "BUST" IN SOME FASHION FOR A TIER OF COUNTIES ON EITHER
SIDE OF THE FRONT, SO THE GOAL WILL BE TO LOCK DOWN THE NORTHWARD
EXTENT OF THE WARM FRONT OVER THE NEXT FEW FORECAST CYCLES.
FRIDAY NIGHT - EARLY SATURDAY...THE FORECAST SHOULD TREND FAIRLY DRY
FOR MOST OF THE REGION DURING THE DAY ON FRIDAY, DUE TO A CAPPING
CAPTURED ON FORECAST SOUNDINGS. THE EXCEPTION WILL BE ACROSS CENTRAL
MN, NORTH OF THE WARM FRONT, WHERE SHOWERS WILL REMAIN
POSSIBLE. LOCATIONS SOUTH OF THE FRONT THAT WILL BE THE FOCUS
FOR A ROUND OF STRONG, TO POTENTIALLY SEVERE THUNDERSTORMS AHEAD
OF A THE PASSING COLD FRONT FRIDAY EVENING. FORECAST SOUNDINGS
SHOW THE PRESENCE OF AN EML, CHARACTERIZED BY 8.5-9C/KM LAPSE
RATES, ALONG WITH 500-1000+ J/KG OF MLCAPE. THE SEVERE WEATHER
SETUP IS SOMEWHAT CONDITIONAL DUE TO THE CAPPING INVERSION
REFERENCED ABOVE, HOWEVER SUFFICIENT SHEAR AND INSTABILITY WILL
BRING THE THREAT FOR A FEW STRONG TO SEVERE THUNDERSTORMS. THE
SPC HAS MAINTAINED A MARGINAL RISK (LEVEL 1/5) IN THE NEW DAY 2
SWO FOR SOUTH/SOUTHEAST MN AND WESTERN WI. THIS INCLUDES THE TC
METRO. ISOLATED INSTANCES OF LARGE HAIL (1.0"+) AND DAMAGING
WIND (60+ MPH) WILL BE THE PRIMARY THREATS. CAMS SHOW THE
CONVECTION DEVELOPING INTO A LINE WEST OF I-35 FRIDAY EVENING
AND MARCHING EAST BEFORE GRADUALLY DISSIPATING IN WI/IA EARLY
SATURDAY.
WEEKEND WET/SNOWY WEATHER...THE NEXT INSTALLMENT IN OUR BUSY
FORECAST INVOLVES THE EASTWARD PROGRESSION OF A TROUGH OVER THE
GREAT PLAINS AND ASSOCIATED SURFACE LOW PRESSURE OVER KS, WHICH
IS PROGGED TO MOVE NORTHEAST ALONG THE BAROCLINIC ZONE INTO IA
AND CONTINUE INTO WI. THIS STORM TRACK PLACES SOUTHERN MN/WESTERN
WI NORTHWEST OF THE SURFACE LOW, IN THE REGION WHERE THE HEAVIEST
PRECIPITATION IS EXPECTED. THE PACIFIC MOISTURE INFLUENCED STORM
SYSTEM IS FORECAST TO PRODUCE LIQUID PRECIPITATION AMOUNTS
BETWEEN 0.5-1.5" AREAWIDE, WITH THE HEAVIEST AMOUNTS ACROSS
SOUTHEAST MN/WESTERN WI AND THE LOWEST AMOUNTS ACROSS CENTRAL
MN. GUIDANCE SUGGESTS THERE MAY BE A DRY PERIOD SATURDAY
MORNING, BEFORE THE SURFACE LOW APPROACHES. HOWEVER, ONCE RAIN
BEGINS IT WILL LIKELY PERSIST THROUGH THE REMAINDER OF SATURDAY
AND INTO EARLY SUNDAY MORNING. COLD AIR WRAPPING INTO THE SYSTEM
WILL ALLOW FOR A TRANSITION TO SNOW ACROSS CENTRAL MN SATURDAY
EVENING. MAJORITY OF DETERMINISTIC SOLUTIONS HAVE CONVERGED ON
CENTRAL MN AS HAVING THE BEST CHANCE FOR ACCUMULATING SNOW. THE
USUAL CHALLENGES RELATED TO SNOW FORECASTING IN LATE MARCH ARE
PRESENT (P-TYPE TRANSITION, DIURNAL TIMING, QPF/P-TYPE), THOUGH
IT DOES SEEM LIKELY THAT COMMUNITIES ACROSS CENTRAL MN WILL
OBSERVE POSITIVE SNOW DEPTH CHANGE ON THE ORDER OF AT LEAST A
FEW INCHES BY SUNDAY MORNING.
A LOOK AHEAD...COOLER AND DRIER TO CLOSE THE WEEKEND AND OPEN THE
UPCOMING WORK WEEK. AS PREVIOUSLY DISCUSSED, THE NEXT STORM SYSTEM
TO WATCH AIMS TO MOVE INTO THE UPPER MIDWEST DURING THE MIDDLE
PORTION OF NEXT WEEK. PREDICTABILITY IN SPECIFICS IS LOW, AS THE ONE
CAN FIND JUST ABOUT ANY P-TYPE SOLUTION THEY PREFER ACROSS THE
GUIDANCE SUITE (HEAVY SNOW ON THE 00Z GFS TO THUNDERSTORMS ON THE
00Z EURO). WE'LL LEAN ON ENSEMBLE GUIDANCE TO BETTER DEFINE THE
FORECAST OVER THE COMING DAYS. GLOBAL GUIDANCE SUGGESTS THAT
THE ACTIVE STORM TRACK STICKS AROUND THROUGH THE FIRST WEEK OR
SO OF APRIL.
AVIATION /06Z TAFS THROUGH 06Z FRIDAY/
ISSUED AT 1225 AM CDT THU MAR 27 2025
BANDS OF SHOWERS ARE MOVING SOUTHEAST ACROSS MINNESOTA AND
WESTERN WISCONSIN EARLY THIS MORNING. THE SHOWERS ARE ASSOCIATED
WITH VFR CIGS BETWEEN 5 TO 10K FEET. GIVEN THAT THE BAND OF
SHOWERS IS RELATIVELY NARROW, OPTED TO KEEP PROB30S AT MKT &
RNH, WHILE PREVAILING WITH -SHRA AT MSP AS UPSTREAM OBS SUGGEST
ANOTHER HOUR OR TWO OF SHOWER POTENTIAL. HAVE TRENDED
AXN/RWF/EAU DRY FOR THE 6Z TAF PERIOD. LIGHT AND AND VARIABLE
WINDS BECOME EASTERLY BY MIDDAY AND WILL SUSTAIN AROUND 10 KTS.
KMSP...CONVERTED THE PROB30 FOR 6SM -SHRA TO PREVAILING OVER
THE FIRST FEW HOURS OF THE TAF WINDOW. VFR THROUGH THE PERIOD,
WITH WINDS INCREASING OUT OF THE EAST THIS AFTERNOON.
/OUTLOOK FOR KMSP/
FRI...VFR, CHC MVFR/-RA LATE. WIND SE BCMG N 10-15 KTS.
SAT...MVFR/RA, CHC IFR. WIND NE 10-15G25 KTS.
SUN...MVFR/RASN BCMG -SN, CHC IFR. WIND NE 10-15G25 KTS.
MPX WATCHES/WARNINGS/ADVISORIES
MN...NONE.
WI...NONE.
DISCUSSION...STRUS
AVIATION...STRUS
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