426
FXUS63 KMPX 172341
AFDMPX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN
641 PM CDT WED SEP 17 2025
KEY MESSAGES
- CHANCES FOR THUNDERSTORMS INCREASE THIS AFTERNOON, WHICH WILL BEGIN
A PERIOD OF UNSETTLED WEATHER EXPECTED TO LAST THROUGH THE
WEEKEND.
- SLOW MOVING STORMS AND HIGH ATMOSPHERIC MOISTURE CONTENT WILL
LIKELY LEAD TO AREAS OF HEAVY RAIN TOTALS EACH OF THE NEXT FEW
DAYS.
DISCUSSION
ISSUED AT 223 PM CDT WED SEP 17 2025
WATER VAPOR IMAGERY THIS AFTERNOON SHOWS BROAD TROUGHING THAT
EXTENDS FROM INTERIOR PACNORTHWEST DOWN TO THE 4-CORNERS REGION THEN
UP TO THE GREAT LAKES. FEATURED WITHIN THIS TROUGHING PATTERN, H700
LOW PRESSURE ROTATES NEAR THE SD/NE BORDER. CLOSER TO HOME, A
STATIONARY BOUNDARY CURRENTLY RESIDES FROM LAKE SUPERIOR DOWN ACROSS
SOUTHWESTERN MN. CLOUDIER SKIES EXIST ACROSS MUCH OF MN, THUS HAVE
DECIDED TO LOWER MAXT VALUES THIS AFTERNOON A COUPLE OF DEGREES
USING A BLEND OF NBM AND HIRES GUIDANCE. THE PREVIOUSLY MENTIONED
SURFACE BOUNDARY WILL CONTINUE TO SERVE AS THE PRIMARY SOURCE OF
CONVECTION FOR THE REST OF TODAY. LATEST RAP GUIDANCE INDICATES THAT
INCREASED MOISTURE WILL ADVECT FROM THE SOUTH THROUGHOUT THE COURSE
OF THIS AFTERNOON AND EVENING. MODERATE MIXED-LAYER INSTABILITY
RANGES BETWEEN 1000 TO 1500 J/KG AND PWATS EXCEED 1.5 INCHES, WHICH
SHOULD MAINTAIN THE RISK OF SCATTERED SHOWERS AND THUNDERSTORMS. THE
WIND FIELD CONTINUES TO APPEAR WEAK, THUS STORMS WILL BE SLOW MOVING
OR MEANDER ON OUTFLOW BOUNDARIES. GIVEN THIS SLOW STORM MOTION
SETUP, IT IS POSSIBLE THAT AREAS THAT DO OBSERVE HEAVIER PERIODS OF
RAINFALL COULD SEE LOCALIZED PONDING/FLOODING. AS OF THE 12Z HREF
QPF LPMM, A NARROW CORRIDOR EXTENDS NEAR GRANITE FALLS OVER TO THE
TWIN CITIES THAT COULD SEE LOCALIZED RAINFALL AMOUNTS BETWEEN 2 TO
2.5 INCHES.
AS WE TRANSITION INTO THE LATTER HALF OF THIS WEEK INTO EARLY NEXT
WEEK, HIGH PRESSURE BUILDING IN OVER SOUTH-CENTRAL CANADA WILL SERVE
AS A REX BLOCK TO OUR CURRENT TROUGHING PATTERN, MEANING OUR POPS
WILL CONTINUE TO REMAIN ELEVATED THROUGH FRIDAY INTO MUCH OF THIS
WEEKEND. IT IS LIKELY THAT DAILY POPS WILL CONTINUE TO INCREASE AS
WE GET CLOSER TO THE WEEKEND. PRECIP ACTIVITY LOOKS TO SIMMER DOWN
EARLY NEXT WEEK ONCE RIDGING OVER THE CENTRAL CONUS DEVELOPS. AS FOR
TEMPERATURES, VALUES WILL RETURN TO THE 70S WITH LOWS IN THE
MID 50S LOWER 60S.
AVIATION /00Z TAFS THROUGH 00Z FRIDAY/
ISSUED AT 639 PM CDT WED SEP 17 2025
INITIAL ROUND OF THUNDERSTORMS HAS MOVED NORTH OF THE TERMINALS
TO OPEN THE 00Z TAF PERIOD. BEST CHANCE FOR -SHRA IN THE SHORT
TERM WILL BE AT RWF/AXN, THOUGH RECENT RADAR TRENDS CONTINUE TO
SHOW A DOWNWARD TREND IN SHOWERS. REGIONAL VIEW SHOWS THE UPPER
LOW SLOWLY SPINNING OVER THE DAKOTAS TO THE WEST. WE DO NOT
EXPECT MUCH EASTWARD MOVEMENT OVER THE NEXT 24-HOURS, WHICH
KEEPS THE TERMINALS IN A REGION OF SOUTHWESTERLY FLOW THAT WILL
FEED ADDITIONAL SHOWER CHANCES. CONFIDENCE IS QUITE LOW IN EXACT
PRECIPITATION WINDOWS AND THE LATEST GUIDANCE HAS TRENDED MUCH
DRIER THROUGH THE NIGHT. GIVEN THE DRY SLOT OVER IOWA, OPTED TO
LEAN THE TAFS IN A DRY DIRECTION THROUGH THE NIGHT IN MOST
CASES. WILL MONITOR LATEST TRENDS AND AMD AS NEEDED. MVFR OR
LOWER STRATUS LOOKS TO BE A FOCUS FOR CIG HEIGHTS LATE
TONIGHT/NEAR DAYBREAK AND WILL MOST LIKELY IMPACT AXN/RWF/STC
AND POSSIBLY MKT. CIGS IMPROVE TO VFR BY LATE MORNING AND WINDS
SUSTAIN 5-10KTS TOMORROW.
KMSP...REMOVED THUNDER FROM THE TAF AS THE MAIN FORCING
MECHANISM FOR THUNDERSTORMS IS A BOUNDARY THAT IS NOW LOCATED
NORTH OF THE TERMINAL. FORECAST REMAINS ONE OF LOWER CONFIDENCE
HEADING INTO TONIGHT AS LATEST GUIDANCE HAS TRENDED DRIER WITH
RESPECT TO SHOWER CHANCES IN THE NEAR TERM. OPTED TO RUN WITH A
DRY 00Z TAF THROUGH 21Z THURSDAY, BUT IT REMAINS POSSIBLE THAT
WE'LL NEED AMD'S FOR WHAT WILL LIKELY BE VFR -SHRA THROUGH THE
NIGHT.
/OUTLOOK FOR KMSP/
FRI...MVFR. -SHRA LIKELY, CHC -TSRA. WIND SE 5-10 KTS.
SAT...CHC MVFR/-TSRA. WIND S 5-10 KTS.
SUN...CHC MVFR/-TSRA. WIND SW 5-10 KTS.
MPX WATCHES/WARNINGS/ADVISORIES
MN...NONE.
WI...NONE.
DISCUSSION...DUNLEAVY
AVIATION...STRUS
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page