185
FXUS63 KMPX 020601
AFDMPX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN
101 AM CDT WED SEP 2 2026
KEY MESSAGES
- MULTIPLE CLUSTERS OF STORMS ARE EXPECTED ACROSS SOUTHERN MN
TONIGHT TO THE NORTH OF A WARM FRONT. THERE IS A LEVEL 2 OF 5
RISK OF SEVERE WEATHER, WITH DAMAGING WINDS BEING THE HIGHEST
RISK.
- A LOW CONFIDENCE PRECIPITATION FORECAST THROUGH LABOR DAY
WEEKEND, WITH MULTIPLE LOW CHANCES FOR RAIN.
- SUMMER-LIKE TEMPERATURES AND HUMIDITY CONTINUE THROUGH LABOR
DAY WEEKEND.
UPDATE
ISSUED AT 836 PM CDT TUE SEP 1 2026
REGIONAL RADAR AND SATELLITE IMAGERY SHOWS THE INCOMING CLUSTER
OF SHOWERS AND STORMS FOCUSED PRIMARILY OVER THE MONSTER
SUPERCELL THUNDERSTORM ONGOING OVER THE SOUTHEAST SOUTH
DAKOTA/NORTHEAST NEBRASKA BORDER. THE TRAJECTORY OF THIS
INDIVIDUAL STORM LOOKS TO TAKE IT EASTWARDS INTO IOWA AND SHOULD
REMAIN SOUTH OF OUR AREA FOR NOW, HOWEVER WE WILL KEEP A CLOSE
EYE ON SOME FURTHER DEVELOPMENT OUT AHEAD OF IT OVER NORTH-
CENTRAL IOWA THAT IS MOVING NORTHEAST TOWARDS OUR SOUTHERNMOST
COUNTIES ALONG I-90. THE EXPECTATION AS THE NIGHT CONTINUES TO
PROGRESS IS FOR THIS CLUSTER OF SHOWERS AND STORMS TO FOCUS
ALONG THE LEADING EDGE OF A DEVELOPING LOW LEVEL JET, WHICH YOU
CAN SEE VIA THE SPC MESOANALYSIS PAGE WITHIN THE MLCAPE GRADIENT
FOCUSED OVER SOUTHERN MINNESOTA, AND THIS GRADIENT IS WHERE WE
EXPECT ANY POTENTIAL STRONGER STORMS OR MCS/BOWING LINE SEGMENT
TO FAVOR MOVING ACROSS. THIS WOULD PLACE THE AREA FROM ROUGHLY
REDWOOD FALLS THROUGH MANKATO AND SOUTHWARDS WITHIN THE MOST
LIKELY AREA TO SEE A STRONGER THUNDERSTORM WITH THE POTENTIAL
FOR SEVERE LEVEL WIND GUSTS, ESPECIALLY IF IT TAKES ON THE
CLASSIC BOWING SHAPE INDICATIVE OF STRONGER WINDS. THE CAM
GUIDANCE HAS BEEN WAFFLING ON THE PACING OF THE STORMS SINCE THE
AFTERNOON, WITH EACH RUN EITHER SPEEDING OR SLOWING THE PACE OF
THE LINE SEGMENT AS IT MOVES THROUGH. AT SLOWEST, IT IS STILL
MOVING EASTWARDS AT AROUND 40-50MPH, SO SOME SEVERE LEVEL WINDS
UP TO 60MPH ARE POSSIBLE DESPITE LOWER LEVEL INVERSION BUILDING
UNDERNEATH THE LOW LEVEL JET, WITH EVEN HIGHER GUSTS POSSIBLE
MAINLY WITHIN ANY POTENTIAL BOWING SEGMENT. THE MORE RECENT HRRR
RUNS HAVE FAVORED THE BOWING SHAPE TO OCCUR AS IT PASSES THROUGH
MANKATO AND APPROACH ROCHESTER IN SOUTHEASTERN MN, WHICH MIMICS
THE LOCATION OF THE MLCAPE GRADIENT AS OF 0130Z. WITH THE TWIN
CITIES AT LEAST 2 TIERS OF COUNTIES NORTH OF THE GRADIENT, IT IS
LOOKING LESS FAVORABLE TO SEE THE STRONGER PORTION OF THE
STORMS, HOWEVER THERE IS STILL AT LEAST SOME ACTIVITY EXPECTED
NORTH OF GRADIENT IN THE FORM OF SOME SCATTERED RAIN SHOWERS.
THESE SHOWERS LOOK TO PERSIST INTO THE MID MORNING TOMORROW
BEFORE DISSIPATING, AND COULD CONTAIN SOME INTERMITTENT
LIGHTNING BUT ARE NOT EXPECTED TO BE STRONG WHATSOEVER. FOR NOW,
WE KEEP A WATCHFUL EYE ON THE RADAR AND SATELLITE AS WE AWAIT
WHATEVER STORMS REACH US LATER TONIGHT AND INTO THE MORNING.
DISCUSSION
ISSUED AT 112 PM CDT TUE SEP 1 2026
WATER VAPOR IMAGERY THIS AFTERNOON SHOWS A SUBTROPICAL RIDGE
CENTERED OVER THE BOOTHEEL OF MO, WITH A MONSOON SHORTWAVE COMING
OUT OF WYOMING THAT WILL RUN AROUND THE NORTH SIDE OF THE RIDGE
THROUGH THE NIGHT. AT THE SURFACE, THERE'S A STATIONARY FRONT A
LITTLE NORTH OF THE I-80 CORRIDOR IN IOWA, WITH DEWPOINTS POOLING UP
INTO THE UPPER 70S ALONG IT. AS WE GO THROUGH THE NIGHT, THE WY
SHORTWAVE AND IA WARM FRONT WILL WORK TOGETHER TO SUPPORT AN
OVERRUNNING CONVECTIVE EVENT OVER SOUTHERN MN. CURRENT EXPECTATIONS
ARE THAT STORMS WILL DEVELOP THIS AFTERNOON IN THE DAKOTAS
ASSOCIATED WITH THE SHORTWAVE, WITH ELEVATED STORMS DEVELOPING NORTH
OF THE WARM FRONT NEAR THE MN/IA BORDER SHORTLY AFTER SUNSET AS THE
LLJ OVER IA STARTS TO RAMP UP (EVENTUALLY GETTING UP INTO THE 35-40
KT RANGE). WE'RE SEEING THE IDEA FROM THE HRRR AND OTHER CAMS THAT
WE COULD SEE MULTIPLE CLUSTERS OF STORMS DEVELOP ON THE NOSE OF THE
LLJ, WITH THE CONVECTION IN THE DAKOTAS THAT DEVELOPS THIS AFTERNOON
EVENTUALLY SWEEPING UP ANY CLUSTERS AHEAD OF IT LATE TONIGHT. THE
FAVORED ZONE FOR HEAVY RAIN AND SEVERE POTENTIAL WILL BE ON THE NOSE
OF THE LLJ AND ALONG THE MUCAPE GRADIENT. THE HREF/REFS CONTINUE TO
SHOW THESE TWO FEATURES LINING UP ALONG THE MN/IA, WITH THE SOUTHERN
TWO OR THREE TIERS OF COUNTIES IN MN BEING MOST AT RISK FOR STORMS,
HEAVY RAIN, AND SEVERE WEATHER TONIGHT, WHICH MATCHES UP WELL WITH
THE DAY 1 SLIGHT RISK FROM THE SPC. FROM THE SEVERE WEATHER
PERSPECTIVE, INSTABILITY (MUCAPE > 3000 J/KG) AND DEEP SHEAR (OVER
40 KTS) ARE CERTAINLY FAVORABLE FOR SEVERE WEATHER, BUT WEAK MID-
LEVEL LAPSE RATES AND OVERNIGHT TIMING/NOCTURNAL STABILIZATION WILL
BE LIMITING FACTORS THAT WILL PUT A CEILING ON THIS BEING A
SIGNIFICANT SEVERE WEATHER SETUP.
FOR THE REST OF WEDNESDAY, WE'RE EXPECTED TO BE DRY AS THE
ATMOSPHERE RECOVERS FROM THE EARLY MORNING CONVECTION. WE'LL HAVE
HEIGHT RISES THROUGH THE DAY, WITH EASTERLY LOW LEVEL WINDS, SO WE
MAY HAVE TO BATTLE SOME MORNING STRATUS AS THE LOW LEVEL MOISTURE
GETS TRAPPED BENEATH A BUILDING INVERSION. THOSE EASTERLY WINDS AND
POTENTIAL FOR MORNING CLOUDS WILL RESULT IN WEDNESDAY BEING THE
"COOLEST" DAY OF THE WORK WEEK, WITH HIGHS GENERALLY IN THE LOW TO
MID 80S, WITH EVER INCREASING DEWPOINTS, AS TROPICAL DEWPOINTS IN
THE 70S BEGIN SPREADING BACK NORTH ACROSS SOUTHERN AND SOUTHWEST MN.
GOING INTO WEDNESDAY NIGHT, WE'LL BEGIN TO SEE THE STATIONARY/WARM
FRONT LIFTING BACK NORTH ACROSS THE AREA. THE LLJ WILL NOT BE AS
STRONG AS WHAT WE SEE TUESDAY NIGHT, BUT WAA WILL STILL BE PRESENT.
HREF SHOWS OVER 2000 J/KG OF MUCAPE COMING UP WITH THAT WARM FRONT
AND THE PRESENCE OF THE WEAK WAA WILL GIVE US A CHANCE OF STORMS,
BUT IT'S HIGHLY UNCERTAIN IF WE'LL GET STORMS TO FIRE WITH OUR
SUBSIDENCE AND BUILDING CAP. THIS UNCERTAINTY IS WHY WE ENDED UP
WITH PRETTY BROAD 20-40 POPS ACROSS THE AREA WEDNESDAY NIGHT AS WE
AWAIT SOME HOPEFULLY BETTER CLARITY ON WHERE MESOSCALE FEATURES WILL
BE.
ANSWERING THE QUESTION OF WHERE MESOSCALE FEATURES WILL BE WILL
CONTINUE TO BE A HEADACHE AS WE GO THROUGH LABOR DAY WEEKEND. WE'LL
SEE A RIDGE AXIS CENTERED OVER US BY SATURDAY, THAT SHIFTS TO OUR
WEST SUNDAY INTO EARLY NEXT WEEK. THAT RIDGE WILL COME WITH STRONG
CAPPING, ALONG WITH A RATHER UNCOMFORTABLE AIRMASS, AS WE SEE HIGHS
NEAR 90 FRIDAY AND SATURDAY, WITH DEWPOINTS IN THE LOW TO MID 70S
SENDING HEAT INDEX VALUES BOTH DAYS UP INTO THE MID TO UPPER 90S,
WELCOME TO AUGTEMBER! THAT RIDGING WILL ALSO RESULT IN CAPPING.
HOWEVER, GIVEN HOW UNSTABLE THE ATMOSPHERE IS, IT'S NOT TAKING MUCH
FOR CONVECTIVE PARAMETERIZATION SCHEMES IN THE DETERMINISTIC MODELS
TO START FIRING OFF CONVECTION. THERE IS LOTS OF SPREAD WITH QPF IN
THE ENSEMBLES, SO THE ON/OFF, MOSTLY LOW CHANCES FOR POPS MAKES
SENSE. AGAIN, WHERE ANY WEAK SHORTWAVES HAPPEN TO MEETUP WITH A
SURFACE BOUNDARY, CHAOS COULD ENSUE, BUT WHERE THAT MAY HAPPEN IS
STILL UNCERTAIN GIVEN THE CAPPING AND WEAK FORCING.
FOR SUNDAY INTO EARLY NEXT WEEK, THE RIDGE AXIS SHIFTS TO OUR WEST,
WITH MN/WI TRANSITIONING INTO NORTHWEST FLOW. THIS IS WHY YOU'LL
NOTICE TEMPERATURES IN THE FORECAST TAKING A STEP BACK AFTER
SATURDAY. WE'LL STILL BE PLACED WITHIN THE NORTHERN STREAM AND
SUSCEPTIBLE TO MESOSCALE SHENANIGANS THOUGH. AT THE MOMENT, IT LOOKS
LIKE SUNDAY NIGHT THROUGH MONDAY NIGHT WOULD BE A PERIOD WITH
INCREASED STORM POTENTIAL, BUT THERE'S STILL TIME FOR THIS TO CHANGE
IN THE COMING DAYS.
AVIATION /06Z TAFS THROUGH 12Z THURSDAY/
ISSUED AT 1258 AM CDT WED SEP 2 2026
THE STRONGEST RAIN AND STORMS HAVE NOW CLEARED ALL OF OUR TAF SITES.
SOME VCTS WILL BE POSSIBLE FOR MKT OVER THE NEXT COUPLE OF
HOURS AS STORMS CONTINUE EASTWARD. -SHRA IS EXPECTED TO CLEAR
ALL SITES AROUND SUNRISE WITH A POTENTIAL FOR A BRIEF PERIOD OF
MVFR CIGS/VSBY AT MKT AND RWF. OTHERWISE LOW TO MID-LEVEL VFR
CIGS WILL IMPROVE THROUGH THIS MORNING BECOMING UPPER-LEVEL SCATTERED
TO FEW BY THE AFTERNOON. LIGHT AND VARIABLE WINDS WILL BECOME
EASTERLY AT ABOUT 5KTS THIS AFTERNOON.
KMSP...-SHRA IS EXPECTED TO WRAP UP WITHIN THE NEXT FEW HOURS. DID
KEEP THE -TSRA MENTION IN THE PROB30 BUT THE THREAT FOR ANY
LIGHTNING IS RAPIDLY DIMINISHING AND STAYING WELL SOUTH OF THE
FIELD. CIGS WILL GRADUALLY CLEAR BY MID-MORNING REDUCING TO A
FEW HIGH CLOUDS BY THE AFTERNOON. WINDS WILL BE LIGHT AND
VARIABLE EARLY AND THEN SHIFT EASTERLY TO ABOUT 5KTS FOR THE
REST OF THE PERIOD
/OUTLOOK FOR KMSP/
THU...VFR, EARLY MVFR/-SHRA POSSIBLE. WIND SE 5-10 KTS.
FRI...VFR. SL CHC -TSRA. WIND S 5-10 KTS.
SAT...VFR. WIND SE 5-10 KTS.
MPX WATCHES/WARNINGS/ADVISORIES
MN...NONE.
WI...NONE.
UPDATE...TDH
DISCUSSION...MPG
AVIATION...DUNLEAVY
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