940
FXUS63 KMPX 271055
AFDMPX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN
555 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.
- 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 217 AM CDT SAT JUN 27 2026
OVERALL, NOT A LOT OF CHANGES IN THE FORECAST FROM PREVIOUS FORECAST
PACKAGES. A LONG DURATION PERIOD OF HOT AND HUMID CONDITIONS BEGINS
ON SUNDAY, LASTING THROUGH NEXT WEEK. CHANCES OF THUNDERSTORMS WILL
EXIST THROUGH THE PERIOD. AS OF NOW, CONFIDENCE IN EXACT TIMING AND
SOME OF THE FINER DETAILS REMAINS LOW.
THIS WEEKEND
OVER THE PAST SEVERAL DAYS, THE UPPER LEVEL REGIME HAS PREDOMINATELY
FEATURED ZONAL TO NORTHWESTERLY FLOW AS UPPER LEVEL RIDGING
DOMINATED THE FLOW OVER THE INTERMOUNTAIN WEST. THE INITIAL
STAGES OF PATTERN CHANGE WILL BEGIN TAKING SHAPE TODAY AS UPPER
LEVEL RIDGE BUILDS IN OVER THE REGION IN RESPONSE TO LONGWAVE
TROUGHING OVER THE NORTHERN ROCKIES AND PACNW. LOCALLY, LOW
LEVEL FLOW WILL RESPOND, BECOMING SOUTH/SOUTHEASTERLY THROUGH
THE DAY. THIS WILL ALLOW TEMPERATURES TO TREND UPWARDS, WARMING
3-7 DEGREES FROM YESTERDAY WITH HIGHS BACK INTO THE LOW TO
MIDDLE 80S ACROSS THE FORECAST AREA. THE AFOREMENTIONED INCREASE
IN LOW LEVEL SOUTHERLY FLOW WILL ALSO PROMOTE SUFFICIENT
WARMING AT 850-700MB. THIS WARMING IN THE LOW TO MID LEVELS WILL
PROMOTE CAPPING (SHOWN IN FORECAST MODEL SOUNDINGS), INHIBITING
ANY CONVECTION DURING THE AFTERNOON/EARLY EVENING HOURS.
A LOBE OF ENERGY EMBEDDED WITHIN THE LONGWAVE TROUGH OVER THE
NORTHERN ROCKIES WILL SWING ACROSS THE DAKOTAS DURING THE DAY.
THIS AND THE ASSOCIATED CONVECTION THAT FORMS IN RESPONSE WILL
MOVE INTO WESTERN MN OVERNIGHT SATURDAY AND INTO EARLY SUNDAY
MORNING. THAT SAID, SHOWER/THUNDERSTORM ACTIVITY WILL BE
SCATTERED TO NUMEROUS IN NATURE DURING THE PRE-DAWN HOURS SUNDAY
MORNING. HIGH RES MODEL GUIDANCE SHOWS THIS ACTIVITY
PROGRESSING EASTWARD ACROSS MN AFTER SUNRISE THROUGH MIDDAY
TIMEFRAME. HOWEVER, THERE STILL REMAINS SOME MINOR UNCERTAINTIES
WITH REGARD TO THIS ACTIVITY AS IT PROGRESSES EASTWARD ACROSS
MN. THAT SAID, PROBABILITY OF PRECIP/THUNDERSTORMS DECREASE THE
FURTHER EAST YOU GO IN CENTRAL AND EASTERN MN DURING THAT
TIMEFRAME WITH CHANCE (25-54%) OF RAIN/STORMS IN THE FORECAST
GRIDS.
MORNING ACTIVITY WILL DISSIPATE AS IT PROGRESSES EASTWARD INTO WI BY
THE EARLY AFTERNOON TIMEFRAME ON SUNDAY. THE AFOREMENTIONED UPPER
LEVEL RIDGE OVERHEAD WILL CONTINUE TO AMPLIFY. THIS WILL PROMOTE
FURTHER WARMING DURING THE AFTERNOON ON SUNDAY, WITH HIGH
TEMPERATURES IN THE MIDDLE TO UPPER 80S ALONG AND SOUTH OF I-94
CORRIDOR. TEMPS ACROSS SOUTHERN MN AND THE MINNESOTA RIVER VALLEY
FROM MANKATO TO REDWOOD FALLS WILL TOP OUT IN THE LOW 90S. THE MORE
NOTICEABLE CHANGE IN SENSIBLE WEATHER CONDITIONS WILL BE THE
MOISTURE AND DEW POINT TEMPERATURES. DP TEMPERATURES WILL SURGE BACK
TO AROUND 70 DEGREES THROUGH THE DAY. CORRESPONDING HEAT INDICES
WILL BE 5-10 DEGREES WARMER THAN THE AIR TEMPS. AGAIN, LIKE
SATURDAY, WARMING 850-700MB TEMPS WILL PROMOTE CAPPING ACROSS
THE MAJORITY OF THE FORECAST AREA, INHIBITING ANY AFTERNOON
CONVECTION. CHANCES (25-50%) OF STORMS REMAIN IN THE FORECAST
FOR PORTIONS OF WI AND EASTERN MN (MILLE LACS, KANABEC, CHISAGO,
ISANTI COUNTIES) DURING THE EVENING HOURS ON SUNDAY. WITH ANY
CONVECTION THAT DOES OCCUR OVER OUR WI COUNTIES, SOME OF THE
STORMS COULD BECOME STRONG TO SEVERE.
NEXT WEEK
ON MONDAY, THE WELL ADVERTISED UPPER LEVEL RIDGE WILL BE FIRMLY
ESTABLISHED OVER THE REGION. IN RESPONSE, HEAT AND HUMIDITY
WILL CONTINUE TO BUILD IN ACROSS THE REGION, WITH AREAWIDE HIGH
TEMPERATURES WELL INTO THE 90S AND DP TEMPS IN THE 70S. THAT
SAID, THERE DOES REMAIN A DEGREE OF UNCERTAINTY WITH REGARD TO
HOW POTENTIAL CLOUD COVERAGE/PRECIP WILL IMPACT MONDAY
TEMPERATURES. BUT AS OF NOW, WE ARE GOING TO CONTINUE MESSAGING
THE DANGEROUS HEAT RISKS MONDAY POSES. FORECAST HIGH
TEMPERATURES ON MONDAY WILL TOP OUT IN THE MIDDLE 90S ACROSS
MUCH OF THE AREA, SLIGHTLY COOLER ACROSS NORTHERN PORTIONS OF
THE CWA, WITH HOTTEST VALUES ACROSS WESTERN MN THAT WILL
APPROACH THE UPPER 90S. GLOBAL DETERMINISTIC MODELS AND THEIR
RESPECTED ENSEMBLE/AI ENSEMBLE SUITES CONTINUE TO SHOW MEDIUM TO
HIGH CONFIDENCE IN TEMPERATURES BEING GREATER THAN 90 DEGREES
(60-95%). THE HOT AFTERNOON TEMPERATURES COUPLED WITH DP TEMPS
IN THE 70S WILL LEAD TO DANGEROUS HEAT INDEX VALUES. THIS LEVEL
OF HEAT WILL BE DANGEROUS FOR ANYONE WITHOUT RELIABLE AC, THOSE
WORKING AND DOING STRENUOUS ACTIVITIES OUTSIDE, YOUNG CHILDREN,
OLDER ADULTS, AND PEOPLE WITH CHRONIC HEALTH CONDITIONS.
THE HOT AND HUMID CONDITIONS WILL CONTINUE THROUGH THE WORK
WEEK WITH DAILY HIGH TEMPS AROUND 90 DEGREES. WHAT MAKES THIS
LONG DURATION PERIOD OF HEAT SO IMPACTFUL, IS THE LACK OF
RECOVERY IN OVERNIGHT TEMPERATURES. OVERNIGHT TEMPERATURES
THROUGH THE WEEK WILL BE IN THE UPPER 60S AND LOW 70S ACROSS THE
AREA. THIS WILL FURTHER BUILD THE HEAT STRESS THAT COULD
POTENTIALLY LAST INTO THE HOLIDAY WEEKEND. WITH ALL THAT BEING
SAID, THE OVERNIGHT FORECAST PACKAGE WILL NOT ISSUE ANY HEAT
RELATED HEADLINES, ALLOWING THE DAYTIME CREW TO ASSESS FRESH
12Z DATA. BUT LIKE MENTIONED IN THE PREVIOUS DISCUSSION, HEAT
HEADLINES ARE INEVITABLE AT SOME IN THE NEXT 24-36 HOURS.
WITH AMPLE HEAT, MOISTURE, AND INSTABILITY IN PLACE ALL OF NEXT
WEEK, THE THREAT FOR THUNDERSTORMS AND HEAVY RAIN WILL BE AT
PLAY. INCREASING MOISTURE THROUGHOUT THE COLUMN WITH PROMOTE
PWAT VALUES 120-170 PERCENT OF NORMAL, SHOWN BY THE GLOBAL AND
GLOBAL AI ENSEMBLE SUITES. HENCE THE THREAT FOR HEAVY RAIN
ANYWHERE STORMS ARE ABLE TO FORM. LIKE MENTIONED ABOVE, WITH
AMPLE HEAT AND INSTABILITY IN PLACE, ANYWHERE CONVECTION OCCURS,
IT WILL BE RATHER ROBUST WITH DAILY CAPE VALUES AT OR ABOVE 1500
J/KG EACH AFTERNOON. HOWEVER, GIVEN THAT EACH DAY WILL FEATURE
SOME SORT OF CAPPING, CONFIDENCE IS LOW WITH REGARDS TO TIMING
AND IMPACTS ON WHEN CONVECTION WILL OCCUR.
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 /12Z TAFS THROUGH 18Z SUNDAY/
ISSUED AT 551 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. CEILINGS DROP EARLY
TOMORROW MORNING WITH MVFR CONDITIONS LIKELY ACROSS WESTERN &
CENTRAL MINNESOTA. SHOWERS & THUNDERSTORMS APPROACH AXN & RWF
AROUND THE END OF THE PERIOD TOMORROW MORNING.
KMSP...DECAYING SHOWERS & THUNDERSTORMS ARE EXPECTED TO MOVE
EASTWARDS ACROSS MINNESOTA THROUGH SUNDAY MORNING. IT'S STILL
UNCERTAIN JUST HOW WIDESPREAD THESE SHOWERS MAY BE BY THE TIME
THEY REACH THE METRO LATE-MORNING, & WHETHER THEY WILL BE
ROBUST ENOUGH TO CONTAIN LIGHTNING
/OUTLOOK FOR KMSP/
SUN PM...VFR. 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...LPR
AVIATION...ETA
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