013
FXUS63 KMPX 271823
AFDMPX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN
123 PM CDT SUN APR 27 2025
KEY MESSAGES UPDATED AT 125PM CDT
- LEVEL 4/5 (MODERATE) RISK FOR MULTIPLE ROUNDS OF SEVERE
THUNDERSTORMS LATE TONIGHT THROUGH MONDAY EVENING. PLEASE HAVE
MULTIPLE WAYS TO RECEIVE WARNINGS SO YOU CAN TAKE SHELTER IF
NEEDED.
- TONIGHT INTO MONDAY MORNING THUNDERSTORMS DEVELOP, AND A FEW
MAY BE SEVERE WITH LARGE HAIL AS PRIMARY THREAT. LOCALIZED
DAMAGING WIND GUSTS ARE POSSIBLE.
- MONDAY AFTERNOON / EVENING, IS THE MOST DANGEROUS PERIOD WITH
STRONG TORNADO POTENTIAL IF STORMS DEVELOP. SCATTERED LARGE TO
VERY LARGE HAIL AND DAMAGING WINDS ARE LIKELY AS WELL.
DISCUSSION
ISSUED AT 347 AM CDT SUN APR 27 2025
NUMEROUS SHOWERS HAVE DEVELOPED ACROSS SOUTHERN AND WESTERN
MINNESOTA EARLY THIS MORNING. THE SHOWERS ARE TIED TO A
MOISTURE GRADIENT THAT WILL CONTINUE EASTWARD DURING THE NEXT
SEVERAL HOURS. DRY BOUNDARY LAYER AIR HAS KEPT AMOUNTS VERY
LIGHT AND POOR LAPSE RATES HAVE KEPT THE CHANCE FOR THUNDER LOW.
BY MID MORNING, MOST OF THE ACTIVITY WILL HAVE DISSIPATED, BUT
EXTENSIVE CLOUD COVER EXTENDING ACROSS ALMOST THE ENTIRETY OF
THE PLAINS SHOULD REMAIN FOR THE REST OF THE DAY UNDERNEATH A
MOIST INVERSION.
A DEEP TROUGH OVER THE SOUTHWESTERN U.S WILL BEGIN TO EMERGE
OVER THE WESTERN PLAINS TONIGHT AND SPAWN AN AREA OF LOW
PRESSURE OVER THE CENTRAL PLAINS TONIGHT. THE 850 MB JET WILL
STRENGTHEN MARKEDLY OVER THE CENTRAL AND SOUTHERN PLAINS TO 55
TO 60 KTS EARLY THIS EVENING. THE NOSE OF THAT JET WILL REACH
SOUTHWESTERN MINNESOTA AROUND MIDNIGHT WHICH WILL BE THE IMPETUS
FOR THUNDERSTORM INITIATION FROM WEST CENTRAL TO SOUTH CENTRAL
MINNESOTA. FORECAST SOUNDINGS ARE LESS CAPPED ABOVE 850 MB THAN
IN EARLIER FORECASTS AND THE ECMWF LIGHTNING FLASH DENSITY
PRODUCT SHOWS FAIRLY ROBUST GROWTH THROUGH THE REST OF THE
NIGHT ACROSS CENTRAL MINNESOTA AND PARTS OF WESTERN WISCONSIN.
ADDITIONAL CLUSTERS OF THUNDERSTORMS FROM THE DAKOTAS MAY ALSO
REACH WESTERN MINNESOTA TOWARD DAWN. ACTIVITY WILL BUILD NORTH
WITH TIME AS THE NOSE OF THE LOW LEVEL JET CONTINUES TO LIFT
NORTH INTO NORTHERN MINNESOTA. IN ADDITION, A STOUT EML WILL
ALSO BE BUILDING IN FROM THE SOUTHWEST, LEADING TO A
STRENGTHENING CAP MONDAY MORNING. THE STRONGEST STORMS ARE
LIKELY TO OCCUR ALONG THE LEADING EDGE OF THE EML WHERE ELEVATED
CAPE IS MAXIMIZED AND CINH IS STILL MINIMAL. THOSE STORMS MAY
CONTAIN LARGE HAIL.
THE WARM FRONT WILL LIFT NORTH MONDAY MORNING AND THERE SHOULD
BE A BREAK IN CONVECTION UNTIL ABOUT MIDDAY. THE EML/CAP WILL
RELAX AROUND THAT TIME AS A DRYLINE BEGINS TO REACH THE WESTERN
MINNESOTA BORDER. NUMEROUS THUNDERSTORMS WILL DEVELOP ALONG IT
AND COULD BRING A HEIGHTENED TORNADO RISK INITIALLY IF STORMS
CAN REMAIN SOMEWHAT DISCRETE. THIS WINDOW MAY NOT LAST LONG
THOUGH AS A SQUALL LINE SHOULD FILL IN RELATIVELY QUICKLY.
DESPITE THAT, ALL HAZARDS ARE POSSIBLE WITH IT, INCLUDING LARGE
HAIL, DAMAGING WINDS, AND TORNADOES. A SECOND LINE OF STORMS
COULD FIRE ALONG THE COLD FRONT WEST OF THE FIRST LINE AN HOUR
OR TWO LATER. THE LINE(S) WILL TRACK EASTWARD ACROSS MINNESOTA
THROUGH THE AFTERNOON AND REACH WESTERN WISCONSIN BY EARLY
EVENING.
SOME UNCERTAINTY REMAINS WHETHER DISCRETE SUPERCELLS CAN FORM
IN AN UNDISTURBED WARM SECTOR AHEAD OF THE LINE(S) OF STORMS.
CAMS ARE NOT TOO OPTIMISTIC, BUT THIS COULD BE A FUNCTION OF THE
PHYSICS OF THE MODELS AND ALSO THE LACK OF A SPARKING MECHANISM
LIKE A FRONT. THE FACT IS, MID LEVEL HEIGHT FALLS WILL
OVERSPREAD THE WARM SECTOR IN A VERY UNSTABLE, HIGHLY SHEARED
ENVIRONMENT WHICH SHOULD RESULT IN AT LEAST A FEW DISCRETE
SUPERCELLS DEVELOPING ACROSS SOUTHERN AND EASTERN MINNESOTA
DURING THE MID TO LATE AFTERNOON. THESE CELLS WOULD POSE THE
GREATEST RISK FOR STRONG TORNADOES (EF2+) AND VERY LARGE HAIL.
THE TORNADO THREAT WILL MAXIMIZE DURING THE EARLY EVENING AS THE
LLJ STRENGTHENS FROM 50 KTS TO 60 KTS, ELONGATING LOW LEVEL
HODOGRAPHS FURTHER.
IT IS WORTH REPEATING - MONDAY IS LIKELY TO BE A DANGEROUS
WEATHER DAY. IT IS IMPORTANT TO HAVE SEVERE WEATHER SAFETY
PLANS IN PLACE NOW SO QUICK AND DECISIVE ACTION CAN BE TAKEN
WHEN STORMS APPROACH AND WARNINGS ARE ISSUED.
AVIATION /18Z TAFS THROUGH 18Z MONDAY/
ISSUED AT 100 PM CDT SUN APR 27 2025
MVFR CLOUDS ARE MOVING IN FROM FROM THE SOUTH, AND SHOULD SPREAD
ACROSS THE REGION LATER THIS AFTERNOON AND EVENING. OVERNIGHT
SHOWERS AND THUNDERSTORMS ARE EXPECTED TO DEVELOP. THESE STORMS
WILL EVENTUALLY LIFT NORTHEAST BY MID-MORNING. A FEW STORMS
COULD PRODUCE LARGE HAIL.
KMSP...
MVFR CEILINGS ARE DEVELOPING A BIT EARLIER, SO HAVE MOVED UP THE
TIMING IN THE MSP TAF TO 00Z. SCATTERED THUNDERSTORMS ARE
EXPECTED TO DEVELOP AFTER MIDNIGHT, WITH THE MOSTLY LIKELY TIME
FRAME NEAR THE MONDAY MORNING RUSH. ANOTHER ROUND OF STORMS IS
EXPECTED MONDAY EVENING, BUT THIS IS BEYOND THE CURRENT TAF
PERIOD. WINDS WILL BE SOUTHEAST THROUGHOUT.
/OUTLOOK FOR KMSP/
TUE...CHC MVFR CIGS IN THE MORNING. WIND NW 10-20 KTS.
WED...VFR, CHC MVFR/-SHRA LATE. WIND SSE 10-15 KTS.
THU...MVFR, CHC -SHRA. WIND NW 15G20 KTS.
MPX WATCHES/WARNINGS/ADVISORIES
MN...NONE.
WI...NONE.
DISCUSSION...BORGHOFF
AVIATION...JRB
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