880
FXUS63 KMPX 150506
AFDMPX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN
1206 AM CDT THU MAY 15 2025
KEY MESSAGES
- SLIGHT (LEVEL 2 OF 5) RISK FOR SEVERE WEATHER TONIGHT INTO
TOMORROW MORNING ACROSS SOUTHWEST MINNESOTA WITH LARGE HAIL
AND DAMAGING WINDS AS THE MAIN THREATS.
- ENHANCED (LEVEL 3 OF 5) RISK FOR SEVERE WEATHER FROM EASTERN
MINNESOTA ACROSS MOST OF WISCONSIN TOMORROW AFTERNOON INTO
EVENING WITH ALL THREATS POSSIBLE: LARGE HAIL, DAMAGING
WINDS, AND A FEW TORNADOES.
- BEHIND THIS PERIOD OF MORE ACTIVE WEATHER WE WILL ENTER INTO A
COOLER, BELOW NORMAL TEMPERATURES, AND WETTER PERIOD.
DISCUSSION
ISSUED AT 223 PM CDT WED MAY 14 2025
REST OF TODAY INTO TOMORROW MORNING... AFTERNOON SATELLITE
IMAGERY SHOWS WIDESPREAD FAIR WEATHER CUMULUS WITH A FEW
ISOLATED THUNDERSTORMS IN WESTERN WISCONSIN. BASED ON 0 HOUR CAM
SOUNDINGS THERE IS INSTABILITY PRESENT ACROSS THE BROADER
REGION. THE VERTICAL MOISTURE PROFILES ARE IN THREE MAIN AREAS
WESTERN MINNESOTA, EASTERN MINNESOTA, AND WESTERN WISCONSIN.
WESTERN MINNESOTA IS THE DRIEST PROFILE WITH LITTLE CHANCE FOR
ANYTHING OUTSIDE OF THE CURRENT CUMULUS DEVELOPMENT. WESTERN
WISCONSIN HAS THE HIGHEST DEW POINTS AND GREATEST MOISTURE
PRESENT WHICH HAS ALLOWED THE DEVELOPMENT OF THUNDERSTORMS.
EASTERN MINNESOTA IS IN BETWEEN THESE IN MOISTURE AND THEREFORE
HAS A CHANCE FOR AN ISOLATED THUNDERSTORM OR TWO. THESE ISOLATED
STORM CHANCES CONTINUE UNTIL THE EVENING WHEN THE SURFACE
STARTS TO COOL. AT THAT POINT ATTENTION TURNS TO THE WEST AS A
POTENTIAL MCS COULD BE MOVING INTO WESTERN MINNESOTA. THIS IS
WHAT THE SPC SLIGHT RISK WAS ISSUED FOR. ALONG AND AHEAD OF A
FRONTAL BOUNDARY ACROSS THE DAKOTAS INTO NEBRASKA STORMS WILL
FORM THIS EVENING. UPSCALE GROWTH IS EXPECTED AS THEY HEAD TO
THE EAST. BY THE TIME THEY REACH MINNESOTA IT MAY EVEN DEVELOP
INTO A FULL MCS. THERE ARE STILL TWO MAIN CAMPS IN THE CAMS: A
NORTH ROUTE AND A SOUTH ROUTE. THE NORTHERLY ROUTE TAKES IT INTO
CENTRAL MINNESOTA AND IS BASED MORE ON THE OVERALL ATMOSPHERIC
FLOW. THE SOUTHERLY OPTIONS REMAINS NEAR THE IOWA BORDER AND IS
ROOTED MORE ALONG THE CAPE GRADIENT. REGARDLESS OF THE PATH CAMS
ARE MAINTAINING IT AS THUNDERSTORMS ACROSS MINNESOTA. WHAT IS
LESS CERTAIN IS HOW SEVERE IT COULD BE. INSTABILITY LOOKS TO BE
STRONG FOR THE MORNING, BUT NOT HIGH. SHEAR LOOKS SUFFICIENT AS
WELL, SO THESE STORMS COULD MAINTAIN THEMSELVES WELL.
TOMORROW EVENING AND NIGHT... AS WE APPROACH LATE MORNING INTO
EARLY AFTERNOON THE NEXT ROUND OF STORM CHANCES WILL START, SO
THERE WILL BE LITTLE OR NO BREAK BETWEEN THESE ROUNDS ACROSS
MINNESOTA. THERE WILL BE A BREAK AT SPECIFIC LOCATIONS, SO THERE
SHOULD BE TIME FOR SOME ATMOSPHERIC RECOVERY. MOISTURE WILL
CONTINUE TO ADVECT INTO THE UPPER MIDWEST IN ADVANCE OF THE
FRONTAL PASSAGE BEHIND THIS NEXT ROUND OF STORMS. ALSO AS THIS
WILL BE AHEAD OF THE FRONTAL PASSAGE THIS WILL STILL BE IN THE
WARM SECTOR. SO PLENTY OF FRONTOGENESIS IN THIS SETUP FOR LIFT
WITH WARM, MOIST AIR OVER US AND COOLER AIR MOVING IN. THAT
COMBINED WITH A STACKED LOW THROUGHOUT THE TROPOSPHERE MEANS
THERE WILL BE NO SHORTAGE OF LIFT. THE WARM AND MOIST AIR AT THE
SURFACE AND LOW LEVELS OF THE ATMOSPHERE COMBINED WITH COOLER
AIR ALOFT WILL PROVIDE AMPLE INSTABILITY. FORECAST HODOGRAPHS
AND THE ASSOCIATED SHEAR ARE THE BIG DIFFERENTIATORS BETWEEN THE
DIFFERENT SPC RISK CATEGORIES FOR TOMORROW. FATHER EAST IN THE
ENHANCED, THERE IS MUCH MORE IMPRESSIVE LOW LEVEL SHEAR AND
THEREFORE A HIGHER TORNADO THREAT THAN TO THE WEST OVER THE
SLIGHT AND MARGINAL RISK AREAS. OVERALL WITH THE AVAILABLE
MOISTURE, STRONG FORCING, AND LOW LEVEL SHEAR THIS EVENT SEEMS
PRIMED FOR A SEVERE THREAT. WE ALWAYS HAVE TO ASK THOUGH WHAT
COULD MAKE THIS NOT HAPPEN? FOR THIS EVENT I'D SAY THE FIRST
ROUND IN THE MORNING IS A COMPLICATING FACTOR. IF THAT ROUND IS
STRONGER OR MORE WIDESPREAD THAN EXPECTED THAT COULD DEPLETE
SOME OF CAPE FOR LATER AND LIMIT THE LATER ENVIRONMENT. THIS IS
A CONCERN ANYTIME YOU HAVE TWO ROUNDS SO CLOSE TOGETHER. FOR
THIS REASON THE BEST CHANCES WILL BE IN WESTERN WISCONSIN AND
NEARBY PARTS OF EASTERN MINNESOTA, AS THEY ARE LESS LIKELY TO
SEE IMPACTS FROM THE FIRST ROUND OF STORMS. AS FOR SEVERE RISKS
ALL ARE POSSIBLE. STEEP LAPSE RATES, AMPLE INSTABILITY, STRONG
LOW LEVEL SHEAR, AND MOISTURE RICH FLOW MEANS THAT SUPERCELLS
ARE POSSIBLE. SUPERCELLS WOULD FAVOR ALL MODES OF SEVERE: WIND,
HAIL, AND TORNADO. HOWEVER WITH A LINEAR FORCING MECHANISM THESE
STORMS COULD GROW UPSCALE MAKING WIND MORE OF A FAVORED THREAT.
SPC IN THEIR 1230 PM DISCUSSION TODAY COMMENTED ON THIS STORM
MODE CONCERN MENTIONING THAT THE ORTHOGONAL LOW LEVEL FLOW WITH
RESPECT TO SURFACE BOUNDARIES FAVORS DISCRETE SUPERCELLS FOR
MODE. HOWEVER THEY DID ALSO NOTE TREND TOWARDS BOWING AND
UPSCALE GROWTH THAT COULD SHIFT TO MORE OF A WIND THREAT. IN
SUMMARY ALL SEVERE MODES ARE POSSIBLE TOMORROW, WITH HIGHER
CHANCES IN EAST CENTRAL MINNESOTA INTO WESTERN WISCONSIN.
FRIDAY INTO NEXT WEEK... THE LOW BEHIND ALL OF THE SEVERE ACTION
WILL BE OVERHEAD ON FRIDAY. THIS BRINGS WITH IT MORE RAIN
CHANCES AND COOLER TEMPERATURES WITH HIGHS IN THE MID 50S TO MID
60S. SATURDAY COULD SEE SOME REMAINING WRAP AROUND SHOWERS, BUT
OVERALL LOWER RAIN CHANCES. COOLER AS WELL ON SATURDAY WITH THE
COOLER FLOW BEHIND THE LOW PUTTING HIGHS IN THE MID TO UPPER
50S FOR MOST, OUTSIDE OF SOME LOWER 60S POSSIBLE IN PARTS OF
SOUTHERN MINNESOTA. SUNDAY WILL BE THE ONE DAY LARGELY DOMINATED
BY HIGH PRESSURE AND SEE SOME SUN. THIS WILL ALLOW FOR SOME
WARMING IN TEMPERATURES UP INTO THE 60S. ANOTHER DEEP LOW IS
FORECAST FOR EARLY TO MID NEXT WEEK. THERE REMAINS SIGNIFICANT
SPREAD NOT JUST IN THE ENSEMBLES, BUT THE GLOBAL DETERMINISTIC
MODELS ABOUT THE TIMING AND TRACK OF THE LOW. WHAT IS CONSISTENT
IS A LOW TRACKING ACROSS THE MIDWEST AND PROVIDING A CHANCE FOR
SUBSTANTIAL RAINFALL. AFTER OUR RECENT HOT AND DRY STRETCH,
THIS WOULD BE MUCH APPRECIATED RAIN TO HELP MAKE OUR FUELS LESS
VULNERABLE FOR FIRE WEATHER ON HOT AND DRY DAYS LATER THIS
SPRING INTO THE SUMMER.
AVIATION /06Z TAFS THROUGH 06Z FRIDAY/
ISSUED AT 1151 PM CDT WED MAY 14 2025
A VERY COMPLEX TAF PERIOD WEATHER-WISE IS UPCOMING, WITH TWO
ROUNDS OF STORMS EXPECTED, FOLLOWED BY STRONG WINDS BEHIND A
COLD FRONT THURSDAY AFTERNOON. OVERALL LITTLE CHANGE FROM THE
INHERITED 00Z TAFS, SO WILL MAINTAIN MUCH OF THE WORDING FROM
THE PREVIOUS AFD:
THE FIRST ROUND OF STORMS WILL EVOLVE OUT OF THE CONVECTION
BLOWING UP OVER CENTRAL NEBRASKA AT THE START OF THE PERIOD.
THE GENERAL TIMING OF THE FIRST LINE FROM THE HRRR AND RRFS
STILL LOOKS GOOD AND REASONABLE. WITH THIS FIRST ROUND WILL
ALSO COME THE THREAT FOR OCCASIONAL MVFR CIGS, WITH SOUTHEAST
WINDS/GUSTS RAMPING UP AS WELL IN RESPONSE TO THE LOW DEEPENING
OVER THE EASTERN DAKOTAS. THERE CONTINUES TO BE PLENTY OF
UNCERTAINTY WITH WHERE/WHEN ROUND 2 GETS GOING, BUT AS ROUND 1
IS DIMINISHING NEAR THE MN/WI BORDER BETWEEN 16Z AND 18Z, ROUND
2 WILL BE FIRING UP OVER SOUTHWEST MN ON A NORTHEASTWARD
ADVANCING OCCLUDED FRONT. ONE THING THAT CAN BE SAID IS THAT
RWF/MKT HAVE THE BEST CHANCE AT MISSING THIS SECOND ROUND,
WITH ALL OTHER TERMINALS LIKELY TO SEE THE THREAT OF STRONG TO
SEVERE STORMS IN THE AFTERNOON. FINALLY, BEHIND THE COLD FRONT,
THERE IS GROWING CONCERN OF SOME VERY STRONG WIND GUSTS. RAP
SOUNDINGS AT RWF/MKT CONTINUE TO INDICATE UPWARDS OF 50 KTS ON
THE GUSTS AND EVEN THE LAV, WHICH CAN UNDERPLAY WIND SPEED
POTENTIAL SOME ON WINDY DAYS HAS SOME REALLY QUITE STRONG SSW
WINDS ALREADY BEHIND THE FRONT. WE'LL ALSO SEE A GOOD SLUG OF
WRAP-AROUND MOISTURE COMING IN TO THE SOUTH OF THE LOW, THOUGH
THAT WON'T REALLY START COMING INTO WESTERN MN UNTIL THE TAIL
END OF THIS PERIOD.
KMSP...SHRA POTENTIAL NUMBER 1 CONTINUES TO LOOK HIGHEST
BETWEEN 13Z AND 15Z, THOUGH THERE IS STILL SOME WIGGLE ROOM AN
HOUR ONE WAY OR ANOTHER ON THAT. THE TSRA RISK WITH THIS ROUND
LOOKS LOW THUS HAVE OMITTED ITS MENTION FOR THURSDAY MORNING,
ALTHOUGH IT IS NOT ENTIRE ZERO CHANCE. ROUND 2 IS MORE
CONCERNING FROM THE SEVERE PERSPECTIVE AND 18Z TO 20Z IS THE
GREATEST THREAT FOR STORMS THEN. STORMS WILL ONLY LAST 30 TO 45
MINUTES, BUT WILL PACK QUITE THE PUNCH. AND THE FUN IS NOT DONE
AFTER THAT LINE OF STORMS. BEHIND THIS FRONT WE COULD SEE VERY
STRONG WINDS, THAT WILL BE MOSTLY CROSS FOR RUNWAY 12/30. MIX
DOWN PROCEDURES ON BUFKIT SOUNDINGS FROM THE RAP SHOWS POTENTIAL
FOR 40+ KT WIND GUSTS IN THIS POST FRONTAL ENVIRONMENT.
/OUTLOOK FOR KMSP/
SAT...MVFR MRNG CIGS LIKELY. WIND NW 10-15G20-25 KTS.
SUN...VFR. WIND NE 5-10 KTS.
MON...MAINLY VFR. CHANCE MVFR/SHRA. WIND ESE 10-15G25KTS.
MPX WATCHES/WARNINGS/ADVISORIES
MN...WIND ADVISORY FROM 2 PM TO 9 PM CDT THURSDAY FOR BLUE EARTH-
FARIBAULT-FREEBORN-MARTIN-STEELE-WASECA-WATONWAN.
WI...NONE.
DISCUSSION...NDC
AVIATION...MPG/JPC
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