868
FXUS63 KMPX 312110
AFDMPX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN
410 PM CDT MON AUG 31 2026
KEY MESSAGES
- BEST CHANCE OF RAIN COMES LATE TUESDAY NIGHT, FOLLOWED BY A
LOW CONFIDENCE PRECIPITATION FORECAST WITH MULTIPLE LOW
CHANCES FOR RAIN THROUGH LABOR DAY WEEKEND.
- SUMMER-LIKE TEMPERATURES AND HUMIDITY CONTINUE THROUGH LABOR
DAY WEEKEND.
DISCUSSION
ISSUED AT 409 PM CDT MON AUG 31 2026
THERE'S AN IMPRESSIVE BOWLING BALL UPPER LOW OVER SOUTHERN
SASKATCHEWAN AND MANITOBA THIS AFTERNOON, WHICH IS DRIVING A COLD
ACROSS WESTERN WI AND FAR SOUTHEAST MN. OUR POSITION SOUTH OF THIS
UPPER LOW PUTS US IN ITS ZONE OF SUBSIDENCE AND MID-LEVEL DRY AIR,
WHICH MEANS WE GET YET ANOTHER DRY COLD FRONT, WHICH SEEMS PAR FOR
THE COURSE FOR AN AUGUST THAT WILL SEE MSP FINISH THE MONTH WITH
JUST 0.46" OF RAIN (WE AVERAGE 4.34"), WHICH IS THE 4TH DRIEST
AUGUST ON RECORD AND JUST THE 8TH OUT OF 156 YEARS WHERE THE TWIN
CITIES FAILED TO GET AT LEAST 1" OF RAIN IN THE MONTH OF AUGUST.
WITH THAT SAID, WE CAN'T COMPLETELY RULE OUT RAIN IN THE MPX AREA
THIS EVENING, BUT THAT CHANCE IS IN EAU CLAIRE AND CHIPPEWA
COUNTIES, TO THE EAST OF CHIPPEWA FALLS AND EAU CLAIRE. EAST OF THE
COLD FRONT, IT'S OPPRESSIVE FOR THE LAST DAY OF AUGUST, WITH
TEMPERATURES IN THE UPPER 80S, DEWPOINTS IN THE MID 70S, AND HEAT
INDEX VALUES IN THE MID 90S. ALL OF THIS HEAT AND HUMIDITY IS
TRANSLATING INTO INSTABILITY, WITH A POOL OF 3000+ J/KG OF MLCAPE
FORECAST DEVELOP AHEAD OF THE FRONT. ALTHOUGH ISOLATED STORM CHANCES
LOOK BETTER EAST OF THE MPX AREA, THE HRRR HAS BEEN INITIATING
STORMS IN EASTERN EAU CLAIRE COUNTY AROUND 23Z FROM THE 15Z RUN
THROUGH ITS MOST CURRENT RUN (19Z), SO WE WILL HAVE TO KEEP AN EYE
ON THE STORM POTENTIAL OUT AROUND STANLEY AND AUGUSTA. AFTER THAT,
THE REST OF THE NIGHT WILL BE QUIET, WITH DRIER AIR MOVING IN
LIMITING THE FOG POTENTIAL IN MN (WHERE DEWPOINTS ARE IN THE MID 50S
ACROSS CENTRAL MN). WI WILL STILL HAVE RADIATIONAL FOG POTENTIAL AS
THEY WILL HOLD ON TO DEWPOINTS IN THE 60S THROUGH THE NIGHT.
THIS DRIER AIRMASS MOVING IN TODAY WILL STAY WITH US THROUGH THE DAY
ON TUESDAY, WITH DEWPOINTS IN THE UPPER 40S TO LOWER 60S MAKING
HIGHS TUESDAY IN THE 80S MORE TOLERABLE.
TUESDAY NIGHT IS WHEN THINGS START TO TURN MORE ACTIVE AS A
SHORTWAVE COMING OUT OF THE SOUTHWEST MONSOON TRAVELS ACROSS
SOUTHERN MN. MOST GUIDANCE SHOWS STORMS DEVELOPING ON THE NOSE OF
THE LLJ AND RIDING THE ELEVATED CAPE GRADIENT EAST TUESDAY NIGHT.
LOOKING AT THE HREF/REFS, THE POOL OF HIGH MUCAPE (OVER 3000 J/KG)
WILL REMAIN NEAR/NORTH OF THE I-80 CORRIDOR IN IOWA, WITH THE LLJ
NOSING UP INTO NORTHERN IOWA. THIS ALL POINTS TO THE MN/IA BORDER
BEING THE ZONE MOST CONDUCIVE TO SEEING THUNDERSTORMS/HEAVY RAIN,
WITH A LIGHTER OVERRUNNING PRECIPITATION AREA GETTING ABOUT AS FAR
NORTH AS THE TWIN CITIES METRO, WHICH WILL LIKELY MEAN CENTRAL MN
INTO NORTHWEST WI MISSES OUT ON THIS ONE. BASED ON WHERE THE LARGE
SCALE FORCING IS FORECAST TO BE, THE NBM THIS MORNING LOOKED TO HAVE
DISPLACED IT'S HIGHER POPS/QPF A BIT TOO FAR NORTH, SO DID NUDGE
POPS A BIT SOUTH TUESDAY NIGHT TO GET CLOSER TO WHERE THE FORCING
IS.
WEDNESDAY THROUGH LABOR DAY BEGINS A PERIOD OF HIGH CONFIDENCE IN
SUMMER-LIKE WARMTH AND HUMIDITY FOR THE FIRST WEEK OF METEOROLOGICAL
FALL, BUT LOW CONFIDENCE ON PRECIPITATION. FIGURING OUT SEVERE
WEATHER POTENTIAL COMES DOWN TO FIGURING OUT WHERE MOISTURE (FOR
SAID STORMS), FORCING (SOMETHING TO PROVIDE LARGE SCALE ASCENT FOR
THAT MOIST AIR), INSTABILITY (SO THAT THE ASCENDING MOIST AIR GOES
UP IN A CONVECTIVE UPDRAFT), AND WIND SHEAR (LET'S ORGANIZE THOSE
STORMS!) ALL COME TOGETHER. THE LARGE SCALE WEATHER PATTERN THROUGH
THE WEEKEND WILL BECOME AMPLIFIED AS A TROUGH DIGS INTO THE PAC NW.
AS IT DIGS INTO THE PAC NW, WE SEE THE RIDGE OVER THE CENTRAL CONUS
AMPLIFY, WITH A WESTERLY TO SOUTHWEST FLOW DEVELOPING ALOFT LOCALLY.
THIS SETUP WILL PUMP DEEP MOISTURE INTO OUR REGION FROM THE GULF AND
SOUTHWEST MONSOON. LOOKING AT THE 4 INGREDIENTS, WE'LL HAVE PLENTY
OF MOISTURE (MEAN EPS PWATS ARE 150% TO 200% OF NORMAL THROUGH THE
WEEKEND), GIVEN THE HEAT AND HUMIDITY, INSTABILITY WILL BE AMPLE,
AND WITH THE UPPER JET ALWAYS OVERHEAD/NEARBY, WE'LL HAVE AMPLE WIND
SHEAR AS WELL. THE BIG UNCERTAINTY THROUGH THE WEEKEND IS THE
FORCING VARIABLE. WITH THE BUILDING UPPER RIDGE, FORCING LOOKS
SUBTLE, WITH PRECIPITATION CHANCES TIED TO WHERE THE WARM FRONT IS
ON A DAILY BASIS AND WHERE ANY WEAK WAVES MOVE THROUGH IN THE UPPER
FLOW. IN OTHER WORDS, IT'S MESOSCALE FEATURES THAT WILL BE DRIVING
OUR PRECIPITATIONS, WHICH IS HARD TO PARSE OUT MORE THAN 48 HOURS IN
ADVANCE. THE RESULT IS WHAT YOU GET WITH THIS FORECAST, NUMEROUS LOW
CHANCES FOR PRECIPITATION THROUGH THE HOLIDAY WEEKEND. AT THIS
POINT, ABOUT THE BEST WE CAN SAY IS WHATEVER WE GET, IT LOOKS TO BE
PREDOMINATELY NOCTURNAL IN NATURE. WILL WE MANAGE TO FINALLY CASH IN
ON A POTENTIAL ACTIVE WEATHER PATTERN? MAYBE, BUT WHEN IT COMES TO
FORECASTING PRECIPITATION IN A DROUGHT, I LIKE TO LIVE BE THE MAXIM
OF WHEN IN DROUGHT, LEAVE IT OUT.
AVIATION /18Z TAFS THROUGH 00Z WEDNESDAY/
ISSUED AT 1226 PM CDT MON AUG 31 2026
A COLD FRONT WAS JUST PUSHING EAST OF I-35 AT THE START OF THIS
PERIOD, BUT WITH THE PARENT UPPER LOW FORCING IT WAY UP IN
SOUTHERN CANADA, THIS WILL BE YET ANOTHER DRY FRONTAL PASSAGE IN
THIS DRY AUGUST. DRIER AIR COMING IN BEHIND THE FRONT WILL
GREATLY LIMIT FOG POTENTIAL TONIGHT, WITH EAU LOOKING TO BE THE
ONLY SITE THAT COULD SEE SOME RADIATIONAL FOG AS THEY WILL HAVE
THE HIGHEST LINGERING DEWPOINTS. NO ISSUES WITH THE WEATHER
THROUGH 18Z TUESDAY, WITH LIGHT SW TO W WINDS AND CLEAR SKIES.
KMSP...WIND DIRECTION MAY START OUT TUESDAY MORNING AROUND 200
DEGREES BEFORE BECOMING ESTABLISHED OUT OF THE WEST BY LATE
MORNING. HOWEVER, SPEEDS FOR ANY MORE SOUTHERLY WINDS TUESDAY
MORNING WILL BE UNDER 5 KTS.
/OUTLOOK FOR KMSP/
TUE EVE...SHRA/TSRA LIKELY. WIND LGT AND VRB OUTSIDE OF TSRA.
WED...VFR. CHC TSRA LATE NIGHT. WIND SE 5 KTS.
THU...VFR. CHC TSRA OVERNIGHT. WIND SE 5-10 KTS.
FRI...VFR. WIND S 5-10 KTS.
MPX WATCHES/WARNINGS/ADVISORIES
MN...NONE.
WI...NONE.
DISCUSSION...MPG
AVIATION...MPG
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