343
FXUS63 KMPX 260903
AFDMPX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN
403 AM CDT FRI JUN 26 2026
KEY MESSAGES
- LONG DURATION HEAT WAVE BEGINS SUNDAY & PERSISTS THROUGH NEXT
WEEK. MONDAY WILL BE THE HOTTEST DAY.
- PERIODIC CHANCES FOR THUNDERSTORMS SUNDAY THROUGH NEXT WEEK.
A FEW THUNDERSTORM COMPLEXES CAPABLE OF SEVERE WEATHER & HEAVY
RAIN ARE POSSIBLE.
DISCUSSION
ISSUED AT 329 AM CDT FRI JUN 26 2026
ANOTHER QUIET & SEASONALLY COOL DAY TODAY, BUT WE'LL SEE A MAJOR
PATTERN CHANGE TO SUMMER DEVELOP THIS WEEKEND & REALLY PEAK
THROUGH NEXT WEEK. WE'LL ALREADY SEE THE START OF WARM ADVECTION
& INCREASING DEW POINTS THROUGH THE DAY TODAY, ALTHOUGH
TEMPERATURES WILL LIKELY TOP OUT IN THE UPPER 70S MOST PLACES.
ISOLATED RAIN SHOWERS & POSSIBLE LATE THIS AFTERNOON & INTO THIS
EVENING AS THE FORCING FROM THE LOW-LEVEL JET RAMPS UP. THE
GREATEST COVERAGE OF THESE SHOWERS LOOKS TO BE ACROSS CENTRAL
MINNESOTA & WESTERN WISCONSIN. THE WARM ADVECTION CONTINUES TO
INCREASE INTO SATURDAY WITH OUR FIRST-ABOVE NORMAL DAY IN TWO
WEEKS EXPECTED AS HIGHS WARM INTO THE MID 80S & DEW POINTS
CONTINUE TO INCREASE INTO THE 60S. THUNDERSTORMS ARE LIKELY TO
DEVELOP SATURDAY AFTERNOON ACROSS THE DAKOTAS AS THE FIRST OF A
SERIES OF IMPULSES RIDES ALONG THE STRENGTHENING RIDGING ALOFT
OVER THE UPPER MIDWEST. THESE STORMS SATURDAY NIGHT SHOULD
FOLLOW THE UPPER LEVEL FORCING & REMAIN OFF TO OUR NORTH & WEST
THROUGH THE NIGHT.
SUNDAY IS WHEN THE HEAT AND HUMIDITY REALLY BEGIN TO TAKE HOLD
AS THE RIDGING ALOFT CONTINUES TO AMPLIFY OVER THE UPPER
MIDWEST. HIGHS ARE EXPECTED TO REACH THE 90S ACROSS MUCH OF
MINNESOTA AND WISCONSIN, WITH DEW POINTS RISING INTO THE UPPER
60S AND 70S. THAT COMBINATION WILL MAKE IT FEEL CLOSER TO 100
DEGREES IN MANY LOCATIONS BY SUNDAY AFTERNOON. ANY MORNING
STORMS OR CLOUDS COULD SLOW THE TEMPERATURE RISE IN SOME AREAS,
BUT THE OVERALL TREND IS TOWARD A VERY WARM AND HUMID DAY.
TEMPERATURES WILL ALSO BE WARMING ALOFT, WITH 700 MB
TEMPERATURES FORECAST TO REACH 15 C OVER THE AREA. THIS VERY
STRONG CAPPING SHOULD PREVENT ANY THUNDERSTORMS FROM DEVELOPING
OVER MUCH OF OUR AREA, BUT WE'LL HAVE TO MONITOR THE GRADIENT
OF HOW MUCH THESE TEMPERATURES COOL OFF TO THE NORTH ACROSS
CENTRAL MINNESOTA & NORTHWEST WI. THE CURRENT MODEL CONSENSUS
GENERALLY KEEPS ANY THUNDERSTORMS SUNDAY EVENING OFF TO OUR
NORTH ACROSS NORTHERN MINNESOTA, BUT THERE IS STILL ENOUGH
UNCERTAINTY TO CONTINUE TO MENTION A THREAT FOR SEVERE
THUNDERSTORMS & HEAVY RAIN ACROSS CENTRAL MN/WESTERN WI SUNDAY
NIGHT.
MONDAY CONTINUES TO LOOK LIKE THE MOST CONCERNING DAY OF THE
FORECAST PERIOD. TEMPERATURES ARE EXPECTED TO CLIMB WELL INTO THE
90S, IF NOT APPROACH 100, WITH TROPICAL DEW POINTS WELL INTO THE
70S EXPECTED. JUST HOW HOT WE GET & HOW HIGH HEAT INDICES CAN
REACH WILL DEPEND GREATLY ON ANY REMNANT PRECIPITATION OR CLOUD
COVER FROM THE POSSIBLE STORMS SUNDAY NIGHT. IF WE REMAIN CLEAR
& DAYTIME HEATING IS MAXIMIZED, WIDESPREAD DANGEROUS HEAT INDEX
VALUES OF 105 TO 110 ARE LIKELY WITH LITTLE COOLING RELIEF
EXPECTED OVERNIGHT OR OVER THE NEXT FEW DAYS. THIS LEVEL OF
HEAT CAN BECOME DANGEROUS QUICKLY, ESPECIALLY FOR ANYONE WITHOUT
RELIABLE AIR CONDITIONING, THOSE WORKING OUTDOORS, YOUNG
CHILDREN, OLDER ADULTS, AND PEOPLE WITH CHRONIC HEALTH
CONDITIONS.
IN ADDITION TO THE HEAT, MONDAY BRINGS A CONDITIONAL BUT
POTENTIALLY SIGNIFICANT SEVERE THUNDERSTORM THREAT. CAPE VALUES
WILL EASILY RISE ABOVE 5000 J/KG GIVEN THE EXTREME HEAT &
HUMIDITY, WHILE SEASONABLY STRONG SHEAR VALUES WILL ALSO BE
PRESENT FROM A DEVELOPING JETSTREAK TO OUR WEST. HOWEVER, THE
CAP WILL BE VERY STRONG, LIKELY EVEN STRONGER THAN SUNDAY'S,
WHICH MAY PREVENT ANY THUNDERSTORM DEVELOPMENT AT ALL. WE'LL
LIKELY HAVE TO MONITOR ANY RESIDUAL OUTFLOW BOUNDARIES FROM THE
PREVIOUS NIGHT'S THUNDERSTORMS BECAUSE EVEN THE SLIGHTEST SOURCE
OF LIFT MAY BE ENOUGH TO SET OFF INTENSE THUNDERSTORMS LATE
MONDAY AFTERNOON & EVENING. IF ANY THUNDERSTORMS ARE ABLE TO
FORM, THEY WILL LIKELY HAVE THE POTENTIAL; FOR SIGNIFICANT
SEVERE WEATHER ALONG WITH TORRENTIAL RAINFALL. AI THUNDERSTORM
OUTLOOK GUIDANCE MAINLY HIGHLIGHTS THE GREATEST SEVERE THREAT
ACROSS NORTHERN MINNESOTA WHERE THE CAP IS WEAKER, BUT STILL
SHOW RATHER HIGH SEVERE PROBABILITIES ACROSS OUR AREA GIVEN THE
HIGH-END ENVIRONMENT IN PLACE.
WE KNOW IT WILL CONTINUE TO BE HOT & HUMID TUESDAY THROUGH THE
REST OF THE WEEK, BUT THE DETAILS BECOME LESS CLEAR GIVEN THE
CHANCES FOR DAILY ROUNDS OF THUNDERSTORMS & PRECIPITATION/CLOUD
COVER POTENTIALLY LIMITING HOW WARM TEMPERATURES CAN REACH
DURING THE AFTERNOON. WHILE TEMPERATURES ARE EXPECTED TO PEAK
ON MONDAY, EXCESSIVE HEAT LOOKS LIKELY TO CONTINUE THROUGH MOST
OF THE WEEK WITH HIGHS IN THE 90S & MUGGY DEW POINTS CREATING
SEVERE DAYS IN A ROW OF HEAT INDEX VALUES AT OR ABOVE 100
DEGREES. THE LONG DURATION OF THIS HEAT & LACK OF ANY
SIGNIFICANCE COOL RELIEF AT NIGHT WILL EXACERBATE THE THREAT TO
HEALTH, ESPECIALLY AMONG AT-RISK & VULNERABLE GROUPS.
THE MAIN TAKEAWAY IS THAT WE ARE HEADING INTO A HIGHER IMPACT
SUMMER PATTERN. THE HEAT BEGINNING SUNDAY AND ESPECIALLY MONDAY
WILL BE DANGEROUS, AND THE SEVERE THUNDERSTORM THREAT SUNDAY
NIGHT INTO MONDAY COULD BECOME SIGNIFICANT IF STORMS ARE ABLE TO
DEVELOP. NOW IS THE TIME TO PLAN FOR SEVERAL DAYS OF HEAT, CHECK
ON PEOPLE WHO ARE MORE VULNERABLE, AND STAY UPDATED ON THE LATEST
FORECAST AS THUNDERSTORM DETAILS BECOME CLEARER.
AVIATION /06Z TAFS THROUGH 12Z SATURDAY/
ISSUED AT 1227 AM CDT FRI JUN 26 2026
VFR CONDITIONS EXPECTED THROUGH THE PERIOD. SKIES CURRENTLY SKC
TO FEW AT 25 KFT WILL CONTINUE OVER THE NEXT FEW HOURS. CLOUDS
WILL INCREASE FROM WEST TO EAST THROUGH THE EARLY MORNING HOURS
WILL ALL TERMINALS AT BKN-OVC AT 20-25 KFT BY SUNRISE. BY LATE
MORNING AND AFTERNOON, FEW-SCT CU DEVELOPMENT WILL OCCUR AT 5-8
KFT WITH HIGHER SCT-BKN CIGS AT 20 KFT. WINDS LIGHT AND VRB OR
OUT OF THE NE THROUGH THE MORNING HOURS, BECOMING E/SE AT 5-10
KNOTS DURING THE LATE MORNING AND AFTERNOON HOURS.
KMSP...NO ADDITIONAL CONCERNS.
/OUTLOOK FOR KMSP/
SAT...VFR. WIND SE AT 10-15 KTS, GUSTS TO 20-25 KTS.
SUN...MVFR CIGS LIKELY AM. CHC OF AM TSRA. WIND 10-17G30 KTS.
MON...VFR. WIND S AT 15-20 KTS, GUSTS TO 30 KTS.
MPX WATCHES/WARNINGS/ADVISORIES
MN...NONE.
WI...NONE.
DISCUSSION...ETA
AVIATION...LPR
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