503
FXUS63 KMPX 270643
AFDMPX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN
143 AM CDT SAT JUN 27 2026
KEY MESSAGES
- LONG DURATION PERIOD OF HEAT AND HUMIDITY BEGINS SUNDAY,
PERSISTING THROUGH THE WEEK. MONDAY WILL BE THE HOTTEST DAY,
BUT HEAT IMPACTS TO BE FELT ALL WEEK WITH LITTLE OVERNIGHT
RELIEF AND THEREFORE A BUILDING HEAT STRESS.
- CONDITIONAL CHANCES FOR THUNDERSTORMS EXIST SUNDAY THROUGH
NEXT WEEK. STORMS WILL BE CAPABLE OF SEVERE WEATHER &
TORRENTIAL RAIN, IF THEY ARE ABLE TO FORM.
DISCUSSION
ISSUED AT 203 PM CDT FRI JUN 26 2026
ANOTHER 36 HOURS OF SEASONABLE WEATHER IS EXPECTED AHEAD OF THE HEAT
AND HUMIDITY. RADAR DEPICTS A FEW RETURNS ACROSS SOUTHERN MINNESOTA
THIS AFTERNOON, BUT NOTHING IS REACHING THE GROUND. HIGHS IN THE
UPPER 70S TODAY AND MID 80S TOMORROW WILL BE MET WITH OVERNIGHT LOWS
IN THE LOW 60S AND MID 60S RESPECTIVELY. LITTLE CHANCES IN THE WAY
OF PRECIPITATION THROUGH SATURDAY EVENING GIVEN THE LARGE CAP THAT
IS FORECAST TO BE IN PLACE. STORMS WILL DEVELOP IN THE DAKOTAS LATER
ON SATURDAY AND PROGRESS INTO WESTERN MINNESOTA OVERNIGHT INTO
SUNDAY MORNING. SCATTERED STORMS ARE MOST LIKELY AFTER SUNRISE ON
SUNDAY FOR MOST, BUT THE CLUSTER OF STORMS THAT ORIGINATED IN THE
DAKOTAS COULD CLIP CENTRAL MINNESOTA PRE-DAWN. FOR THE MOST PART,
THAT EARLIER ACTIVITY SHOULD STAY TO THE NORTH, WITH MORE SCATTERED
STORMS TO FOLLOW BETWEEN 5AM-12PM.
SUNDAY AFTERNOON IS WHEN THE HEAT BEGINS TO BUILD WITH AN AMPLIFYING
RIDGE. HIGHS WILL BE IN THE LOW 80S (WEST WI, CENTRAL AND EAST MN)
TO LOW 90S (SOUTH AND SOUTHWEST MN), BUT HEAT INDICES WILL BE 5
TO 10 DEGREES WARMER THAN THAT DUE TO AN INFLUX OF MOISTURE AND
THUS HIGHER DEWPOINTS. AGAIN, STRONG CAPPING SHOULD PREVENT ANY
THUNDERSTORMS FROM DEVELOPING OVER MUCH OF OUR AREA, BUT
MONITORING WILL BE NECESSARY. THE CURRENT FORECAST GENERALLY
KEEPS SUNDAY EVENING STORMS TO THE NORTH, WITH AREAS ALONG A
LINE FROM MORA TO ST.CROIX FALLS TO EAU CLAIRE ON THE SOUTHERN
EDGE OF WHERE ACTIVITY WOULD BE MOST LIKELY. ALTHOUGH CHANCES
ARE ON THE LOWER END, WE CONTINUE TO REMAIN ALERT TO THE THREAT
FOR SEVERE THUNDERSTORMS AND HEAVY RAIN ACROSS CENTRAL AND
EASTERN MN/WESTERN WI SUNDAY NIGHT.
WITH AREAWIDE MAX HEAT INDICES AT OR GREATER THAN 105, MONDAY
IS CERTAINLY THE DAY WITH ATTENTION GRABBING NUMBERS. JUST HOW
HIGH TEMPERATURES/THE HEAT INDEX GO WILL DEPEND ON CLOUD COVER
AND POTENTIAL PRECIPITATION, BUT WE WILL WITHOUT A DOUBT BE
APPROACHING/AT DANGEROUS HEAT RISKS. AIR TEMPERATURES SHOULD
GENERALLY REMAIN IN THE 90S, WITH HOTTEST VALUES IN WESTERN MN
POTENTIALLY OVER 100. THEREFORE, RECORD-BREAKING TEMPERATURES
ARE NOT LIKELY (STC/MSP/EAU ALL HAVE RECORD HIGHS GREATER THAN
OR EQUAL TO 100 FOR THE LATE JUNE/EARLY JULY TIMEFRAME). WHAT
MAKES THIS HEAT DANGEROUS IS THE WARM OVERNIGHT LOWS AND HIGH
DEWPOINTS LEADING TO HIGH HEAT INDICES. THIS LEVEL OF HEAT WILL
ESPECIALLY BE DANGEROUS FOR ANYONE WITHOUT RELIABLE AIR
CONDITIONING, THOSE WORKING OUTDOORS, YOUNG CHILDREN, OLDER
ADULTS, AND PEOPLE WITH CHRONIC HEALTH CONDITIONS.
MONDAY WILL HAVE THE HIGHEST TEMPERATURES, BUT THE HEAT IMPACTS WILL
CONTINUE, IF NOT WORSEN, WELL INTO THE WEEK. OVERNIGHT TEMPERATURES
(LOWS IN THE UPPER 60S AND LOW 70S) AND OPPRESSIVE DEWPOINTS
(60-70+) WILL CONTRIBUTE TO A LONG DURATION HEAT RISK WITH
LITTLE OVERNIGHT RECOVERY. THIS WILL BUILD THE HEAT STRESS,
POTENTIALLY LASTING INTO THE HOLIDAY WEEKEND. HEAT HEADLINES ARE
INEVITABLE AT SOME POINT IN THE NEAR FUTURE.
NOW TO PIVOT TO THE THUNDERSTORM AND HEAVY RAIN THREAT THROUGH THE
PERIOD. THE AIFS ENS IS FORECASTING PWATS ANYWHERE FROM 120-160% FOR
MUCH OF THE WEEK, LEADING TO AN INCREASED THREAT FOR TORRENTIAL
RAINFALL ANYWHERE STORMS ARE ABLE TO FORM. AS ONE COULD IMAGINE WITH
AMPLE HEAT AND MOISTURE, THERE WILL BE GOBS OF INSTABILITY
AVAILABLE. THE ECMWF IS FORECASTING MUCAPE VALUES GREATER THAN 1500
J/KG SUNDAY THROUGH THE 4TH, PEAKING AS HIGH AS 5000-6000 J/KG. TAKE
THIS INFORMATION WITH A GRAIN OF SALT GIVEN THE LARGE CAP THAT WILL
LIKELY BE IN PLACE. ANOTHER THING TO CONSIDER RELATING THE STORM TO
HEAT THREAT IS THAT IF STORMS DO OCCUR AT A GIVEN LOCATION, THAT
WILL BRING AT LEAST TEMPORARY RELIEF TO THE HEAT RISK.
TO SUMMARIZE, A CONDITIONAL SEVERE WEATHER THREAT IS PRESENT MOST
(ALL?) DAYS NEXT WEEK. THE KEY WILL BE TO KEEP A CLOSE EYE ON
POTENTIAL FORCING TO SEE WHAT STORMS MAY COME TO FRUITION. IF WE TAP
INTO INSTABILITY, THINGS WILL GET INTERESTING STORM WISE GIVEN THE
HIGHLY PRIMED ENVIRONMENT. IF STORMS GO, THEY'LL GO. IT ISN'T
WORTH THE TIME TO TRY AND PINPOINT SPECIFICS AT STAGE. ONCE CAMS
ARE AVAILABLE, THE THREAT COULD BE MORE REFINED.
AVIATION /06Z TAFS THROUGH 12Z SUNDAY/
ISSUED AT 141 AM CDT SAT JUN 27 2026
VFR THROUGH THE PERIOD WITH SCT/BKN MID-LEVEL CLOUDS. SOUTHEAST
WINDS THROUGH THE PERIOD INCREASING TO 10-15 KTS BY LATE
MORNING, ALONG WITH WIND GUSTS OF 20-25 KTS.
KMSP...NO ADDITIONAL CONCERNS.
/OUTLOOK FOR KMSP/
SUN...MVFR CIGS/TSRA POSSIBLE EARLY. WIND SE 20G30 KTS.
MON...VFR. CHC PM TSRA. WIND S 15-20G30 KTS.
TUE...VFR. WIND SW 15-20G30 KTS.
MPX WATCHES/WARNINGS/ADVISORIES
MN...NONE.
WI...NONE.
DISCUSSION...PV
AVIATION...ETA
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