569
FXUS63 KMPX 171753
AFDMPX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN
1253 PM CDT SUN MAY 17 2026
KEY MESSAGES
- SEVERE THUNDERSTORMS LIKELY TONIGHT WITH DAMAGING WIND GUSTS
THE PRIMARY HAZARD. THE HIGHEST THREAT IS ACROSS SOUTHERN
MINNESOTA.
- ANOTHER ROUND OF THUNDERSTORMS IS LIKELY MONDAY NIGHT. SEVERE
THUNDERSTORMS ARE POSSIBLE ACROSS SOUTHEAST MINNESOTA &
WESTERN WISCONSIN.
DISCUSSION
ISSUED AT 257 AM CDT SUN MAY 17 2026
ISOLATED RAIN SHOWERS HAVE DEVELOPED ON CUE OVERNIGHT, DRIVEN BY
FORCING ON THE NOSE OF STRONG LOW & MID-LEVEL WARM ADVECTION
FROM THE LOW-LEVEL JET. THESE SHOWERS ARE EXPECTED TO DISSIPATE
AFTER SUNRISE AS THE LOW-LEVEL JET WANES IN INTENSITY, BUT
ANOTHER REGION OF SHOWERS & THUNDERSTORMS IS LIKELY TO CONTINUE
OVER SOUTHEASTERN MINNESOTA & WEST-CENTRAL MINNESOTA AS A MCV
FROM OVERNIGHT CONVECTION ACROSS IOWA MOVES THROUGH THE AREA.
THE MAIN TREND TO WATCH THIS MORNING & AFTERNOON WILL BE HOW
OUR TEMPERATURES & DEWPOINTS RESPOND THROUGH THE DAY. WE ARE
CURRENTLY SITTING UNDER STRONG NORTHEASTERLY FLOW, & WILL
REMAIN COOL & DRY UNTIL WINDS BECOME MORE SOUTHEASTERLY & ALLOW
FOR DEWPOINTS TO RISE INTO THE UPPER 50S & 60S. CONFIDENCE IS
HIGH THAT WE'LL SEE THESE MORE UNSTABLE CONDITIONS DEVELOP
ACROSS SOUTHERN MINNESOTA, BUT IT'S MORE UNCERTAIN HOW FAR NORTH
INTO CENTRAL MINNESOTA & WESTERN WISCONSIN WE'LL SEE
TEMPERATURES IN THE 70S & DEW POINTS NEAR 60 EXTEND BY LATE
AFTERNOON. WIDESPREAD CLOUD COVER THROUGH THE DAY WILL PUT A
LIMIT ON THE EXTENT OF SOLAR HEATING THIS AFTERNOON, SO WATCHING
WHERE WINDS BECOME SOUTHEASTERLY THIS AFTERNOON WILL BE KEY ON
IDENTIFYING WHERE THE ENVIRONMENT FOR SEVERE WEATHER EXISTS
LATER THIS EVENING.
THUNDERSTORMS ARE EXPECTED TO DEVELOP LATE THIS AFTERNOON
ACROSS THE ASTERN DAKOTAS, NEAR THE TRIPLE POINT OF A LOW
FORECAST TO TRACK NORTHEASTWARDS FROM THE CENTRAL PLAINS INTO
MINNESOTA & WISCONSIN. THESE STORMS WILL LIKELY BECOME
SUPERCELLULAR GIVEN THE IMPRESSIVE ENVIRONMENT FOR SEVERE
WEATHER OVER THE DAKOTAS & CENTRAL PLAINS, BUT WILL LIKELY
MERGE INTO A LINEAR MCS AND/OR MULTIPLE LINE SEGMENTS AS THEY
MOVE INTO WESTERN MINNESOTA AROUND 7-9 PM THIS EVENING. ALL
MODES OF SEVERE WEATHER WILL BE POSSIBLE WITH THESE INITIAL
SUPERCELLULAR STORMS, WITH VERY LARGE HAIL (2-3" IN DIAMETER) &
A FEW TORNADOES ACCOMPANYING A DAMAGING WIND THREAT. AS THE
DISCRETE STORMS TRANSITION TO A MCS OR LINE SEGMENTS, DAMAGING
WIND GUSTS WILL BECOMING THE PREDOMINANT SEVERE THREAT, ALTHOUGH
A FEW QLCS TORNADOES ARE ALSO POSSIBLE GIVEN THE SOUTHEASTERLY
FLOW AHEAD OF THE STORMS GENERATING IMPRESSIVE LOW-LEVEL WIND
SHEAR & HELICITY. AS MENTIONED ABOVE, WHERE SOUTHEASTERLY WIND
DEVELOP & ALLOW MORE INSTABILITY IS GOING TO BE KEY FOR
DETERMINING WHERE THE SEVERE THREAT FROM THESE THUNDERSTORMS IS
GOING TO CONTINUE INTO THE EVENING AS STORMS MOVE EASTWARDS
ACROSS MINNESOTA & WISCONSIN. HIGH-RESOLUTION ENSEMBLE GUIDANCE
REALLY HIGHLIGHTS SOUTHERN MINNESOTA FOR THE GREATEST SEVERE
ENVIRONMENT, UP TO THE LATITUDE OF MARSHALL/MANKATO/RED WING,
WHERE WE SEE THE POTENTIAL FOR SURFACE-BASED CAPE VALUES
APPROACHING 1000 J/KG. HOWEVER, WE COULD STILL SEE A LOW
CAPE/HIGH-SHEAR ENVIRONMENT EXTEND NORTHWARDS INTO CENTRAL
MINNESOTA & WESTERN WISCONSIN AS LONG AS STORMS ARE STILL ABLE
TO TAP INTO SOME SORT OF SURFACE- BASED INSTABILITY. VARIOUS
HIGH-RESOLUTON MODEL SOLUTIONS TEND TO DEPICT THE HIGHEST
CONCENTRATION OF DAMAGING WIND GUSTS & QLCS TORNADO POTENTIAL
MAINLY OCCURRING ACROSS THIS REGION OF SOUTHERN MINNESOTA, BUT
SOME POTENTIAL STILL EXISTS FARTHER TO THE NORTH & EAST.
TIMING- WISE, HIGH-RESOLUTION MODELS ARE GENERALLY IN AGREEMENT
WITH MOVING THE THUNDERSTORM COMPLEX REACHING WESTERN MN THROUGH
7-9 PM, CENTRAL MN & THE METRO BETWEEN 9-11 PM, & WESTERN WI
BETWEEN 11 PM - 1 AM.
THE THUNDERSTORMS WILL BEGIN WEAKENING AROUND MIDNIGHT AS
INSTABILITY WANES, LIKELY REDUCING THE THREAT FOR SEVERE
WEATHER ACROSS WESTERN WISCONSIN. SHOWERS & THUNDERSTORMS WILL
STILL BE ONGOING INTO THE OVERNIGHT HOURS, WITH THE
PRECIPITATION MOSTLY OVER ACROSS OUR AREA BY SUNRISE. FOR
MONDAY, WE WILL LIKELY BE DRY THROUGH THE DAY BUT WILL HAVE TO
MONITOR WHERE ANY OUTFLOW BOUNDARIES OR REMNANT FROM MCVS FROM
THE OVERNIGHT STORMS SET UP DURING THE DAY. ANOTHER ROUND OF
SHOWERS & THUNDERSTORMS IS LIKELY MONDAY NIGHT, BUT WE WILL
LIKELY REMAIN NORTH OF THE BEST SYNOPTIC ENVIRONMENT FOR SEVERE
WEATHER ACROSS IOWA & SOUTHERN WISCONSIN. CAN'T RULE OUT
SOMETHING INTERESTING HAPPENING IF WE GET A MESOSCALE BOUNDARY
TO SET UP ACROSS OUR AREA MONDAY EVENING, BUT OTHERWISE WE'RE
LOOKING AT MOSTLY A RAIN EVENT. RAINFALL-WISE, WE'LL SEE OUR
FIRST SOAKING RAINFALL OF THE MONTH WITH MOST OF THE AREA
EXPECTED TO SEE AT LEAST 1-2" BETWEEN THE THUNDERSTORMS TONIGHT
& MONDAY NIGHT. LOCALIZED AMOUNTS OF 3-4" LOOK POSSIBLE BASED
ON INDIVIDUAL HIGH- RESOLUTION MODEL RUNS, DEPENDING ON WHICH
AREAS GET THE SLOWEST- MOVING THUNDERSTORMS.
BY TUESDAY, SEASONABLY COOL & DRY WEATHER RETURNS AS THE UPPER
MIDWEST RETURNS TO A PATTERN OF TROUGHING ALOFT. THE NEXT ROUND
OF DISTURBANCES & PRECIPITATION ARRIVES FRIDAY, WITH ADDITIONAL
CHANCES FOR SHOWERS & THUNDERSTORMS LATER ON THE MEMORIAL DAY
WEEKEND
AVIATION /18Z TAFS THROUGH 18Z MONDAY/
ISSUED AT 1233 PM CDT SUN MAY 17 2026
BROKEN SKY COVER THANKS TO A MID-LEVEL DECK TO START THE
PERIOD. WE'LL SEE CEILINGS STEADILY DECREASE AND HIT MVFR BY
LATE AFTERNOON/EARLY EVENING. I HAVE DELAYED THE ARRIVAL OF MVFR
& IFR CIGS VS THE 12Z TAFS BASED ON LATEST TRENDS AND FORECAST
SOUNDINGS.
ATTENTION TURNS TO THE AFTERNOON TS THAT WILL DEVELOP AFTER 20Z
ACROSS EASTERN SD. THIS SHOULD CONGEAL INTO A LINE OF TS BY THIS
EVENING BEFORE TRACKING EASTWARD ACROSS THE AREA. TIMING OF THE
TS LINE MAY NEED ADJUSTED. TS MOVES INTO SW MN AROUND 00Z AND
TRACKS NORTHEAST THROUGH 06Z WHERE IT BEGINS TO WEAKEN OVER W
WI.THERE IS STILL A SIGNAL FOR STRONG WARM ADVECTION EAST ACROSS
S MN/W WI THAT MAY RESULT IN SHOWERS DEVELOPING THIS EVENING
AHEAD OF THE TS COMING OUT OF SD. ANOTHER CHANGE WAS TO SWAP
OUT PROB30 FOR TEMPO AT ALL SITES BUT AXN & EAU. THESE TWO
LOCATIONS HAVE SOME UNCERTAINTY IF WE'LL SEE TS VS SHRA, BUT CAN
AMD LATER. TSRA ENDS AFTER 06Z AND SHRA BY 08Z AS THE COMPLEX
EXITS OUR AREA. MVFR AND IFR CIGS LINGER THROUGH THE END OF THE
TAF. SITES SHOULD REMAIN DRY AFTER DAYBREAK MONDAY THROUGH END
OF TAF.
KMSP... EAST WINDS WILL GRADUALLY SHIFT TO ESE WINDS THIS
AFTERNOON. SPORADIC GUSTS AROUND 25KTS ARE LIKELY THROUGH EARLY
EVENING. THERE IS SOME UNCERTAINTY REGARDING THE ARRIVAL &
INTENSITY OF ANY TS THIS EVENING. OPTED FOR A TEMPO AND WILL AMD
TO TWEAK TIMING AS NECESSARY. WINDS SHIFT TO THE WEST-NORTHWEST
BY DAYBREAK MONDAY. I HAVE OPTED TO LEAVE OUT ANY MENTION OF
SHRA OR TS MONDAY AFTERNOON. BEST SIGNAL FOR ANY PRECIPITATION
WILL BE JUST AFTER END OF TAF MONDAY EVENING.
/OUTLOOK FOR KMSP/
TUE...MVFR. WIND NW 10-15G25KTS.
WED...VFR. WIND NNW 5-10KTS.
THU...VFR. WIND S 10-15G25KTS.
MPX WATCHES/WARNINGS/ADVISORIES
MN...NONE.
WI...NONE.
DISCUSSION...ETA
AVIATION...BPH
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