393
FXUS63 KMPX 171906
AFDMPX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN
206 PM CDT THU SEP 17 2026
KEY MESSAGES
- WIDESPREAD STEADY SOAKING RAIN IS EXPECTED FRIDAY INTO EARLY
SATURDAY.
- THE HIGHEST AMOUNTS WILL BE NEAR I-90, WHERE HEAVY RAIN
AND FLOODING ARE POSSIBLE, MAINLY FRIDAY EVENING.
- LOOKING AHEAD INTO NEXT WEEK, TEMPERATURE REMAIN NEAR TO
SLIGHTLY BELOW NORMAL, WITH A FEW SMALL CHANCES FOR RAIN.
DISCUSSION
ISSUED AT 157 PM CDT THU SEP 17 2026
TONIGHT THROUGH FRIDAY NIGHT...THE MAIN CONCERN IS THE
POTENTIAL FOR HEAVY RAIN AND FLOODING ACROSS SOUTHERN MINNESOTA.
LATEST GUIDANCE SUPPORTS THE GREATEST RISK FOR THUNDERSTORMS
FRIDAY EVENING ALONG AND NEAR I-90. THESE STORMS WILL HAVE
ABUNDANT MOISTURE, AND COULD BE SLOW MOVING AND/OR BACK
BUILDING. HOURLY RAINFALL RATES OF 2 TO 3 INCHES WOULD BE
POSSIBLE, SO ANY AREAS THAT SEE A COUPLE HOURS OF STORMS HAVE A
POTENTIAL FOR RAINFALL TOTALS OF 4, 5, 6 INCHES, OR MORE. NO
FLOOD WATCHES HAVE BEEN ISSUED, BUT THESE WOULD BE NEEDED LATER
IF THE TRENDS CONTINUE TO HIGHLIGHT SOUTHEAST MINNESOTA.
GENERALLY IN THE AREA OF OWATONNA AND ALBERT LEA AND POINTS
EAST.
ELSEWHERE, WIDESPREAD, SOAKING RAIN IS STILL EXPECTED, BUT THE
RAINFALL RATES WILL BE MUCH LESS GIVEN THE LACK OF INSTABILITY.
FORECAST SOUNDINGS OFF THE RRFS AND HRRR FOR MSP ONLY HAVE
ABOUT 0.25 INCHES IN ANY GIVEN HOUR, SO EVEN THOUGH TOTAL
AMOUNTS OF 1 TO 2 INCHES OF RAIN SEEMS LIKELY BY THE TIME THE
RAIN ENDS FRIDAY NIGHT, THE RISK FOR FLOODING ACROSS CENTRAL MN
AND WEST CENTRAL MN IS PRETTY LOW, ESPECIALLY CONSIDERING THE
DRY ANTECEDENT CONDITIONS.
THE SET UP FOR ALL OF THIS TIES BACK TO A SHORTWAVE THAT WILL LIFT
UP FROM THE SOUTHWEST LATER TONIGHT. A STATIONARY BOUNDARY THAT WAS
LAID OUT WEST-TO-EAST ALONG THE I-80 CORRIDOR WILL LIFT NORTHWARD AS
A WARM FRONT. PRECIPITABLE WATER VALUES ARE IN EXCESS OF 2 INCHES
ALONG THIS WARM FRONT, AND STRONG SOUTHEAST WINDS ALONG THE FRONT
WILL LEAD TO WIDESPREAD RAIN AND STORMS IN THE DAKOTAS OVERNIGHT.
THESE WILL MOVE EASTWARD INTO MINNESOTA AND WISCONSIN ON FRIDAY, BUT
WEAKEN AS THEY RUN OUT OF INSTABILITY. THIS WILL LEAD TO LOWER
RAINFALL RATES, GENERALLY AROUND 0.25 INCHES PER HOUR. THE LONE
EXCEPTION COULD BE AN ENHANCEMENT OF FGEN/RAIN ALONG AN ELEVATED
FRONT, BUT EVEN THEN IT WOULD BE TOUGH TO GET RATES OVER AN INCH PER
HOUR GIVEN THE LACK OF INSTABILITY.
FARTHER SOUTH HOWEVER IS A DIFFERENT STORY. FORECAST SOUNDINGS SHOW
ELEVATED INSTABILITY BUILDING NEAR I-90, AND SOME HIRES
GUIDANCE SHOW THUNDERSTORMS DEVELOPING FRIDAY EVENING. THIS IS
THE MAIN AREA OF CONCERN FOR FLOODING, GENERALLY AFTER 6PM, AND
ENDING BY MIDNIGHT.
SATURDAY, SUNDAY AND NEXT WEEK...RAIN WILL EXIT THE REGION FRIDAY
NIGHT AS THE WARM FRONT PUSHES SOUTH, LEAVING LOW CLOUDS BEHIND. A
FEW SHOWERS COULD REDEVELOP ON SATURDAY, MAIN TO THE SOUTH ALONG I-
90 AGAIN. GIVEN THE CLOUDS, NORTHEAST WINDS, AND COOLER AIRMASS,
AFTERNOON HIGHS WILL BE IN THE MID 60S, GIVING A FALL-LIKE FEEL TO
THE WEEKEND.
LOOKING AHEAD, THE AFOREMENTIONED WARM FRONT WILL STALL OUT ACROSS
IOWA AND ILLINOIS, KEEPING THE RAIN CHANCES TO THE SOUTH. THERE ARE
A FEW SMALL CHANCES FOR RAIN (10 TO 20 PERCENT) AT TIMES, BUT
OVERALL DRIER ENSEMBLE GUIDANCE SHOWS DRIER WEATHER FOR NEXT
WEEK.
AVIATION /18Z TAFS THROUGH 00Z SATURDAY/
ISSUED AT 1240 PM CDT THU SEP 17 2026
IFR TO MVFR CIGS CONTINUE OVER THE NEXT FEW HOURS. HOWEVER, WE
ARE STARTING TO SEE MOVE SCT TO BKN CU MOVING NE TO SW ACROSS
THE REGION WITH CIGS INCREASING BACK TO VFR BY 19-20Z. WINDS
WILL BE LIGHT OUT OF THE NE/E THROUGH THE AFTERNOON AND EVENING.
BKN TO OVC RETURN TO THE REGION TONIGHT AS THE NEXT STORM SYSTEM
BRINGS WIDESPREAD LIGHT TO MODERATE SHOWERS THROUGH MOST OF
FRIDAY. TIMING FOR ONSET OF LIGHT SHRA IS BETWEEN 11-13Z WITH
CIGS AND VIS LOWERING SHORTLY AFTER FROM SW TO NE THROUGH THE
MORNING HOURS. MODERATE SHRA EXPECTED TO BEGIN AROUND 17-19Z
WITH FURTHER LOWERING OF CIGS AND VIS TO MVFR AND IFR
CATEGORIES. TEMPO GROUPS HAVE BEEN ADDED TO THIS TAF ISSUANCE,
INDICATING THE REDUCTIONS IN CIGS AND VIS. THREAT FOR TS IS VERY
LOW AS CONVECTIVE PARAMETERS DON'T SUPPORT MUCH IN TERMS OF
CONVECTION AND LIGHTNING. THAT SAID, EVEN THOUGH THE THREAT FOR
TS IS LOW, IT'S NOT ZERO. BUT FOR NOW, WITH LOW CONFIDENCE,
THERE'S NO MENTION IN TAF.
KMSP...MVFR CIGS WILL IMPROVE TO VFR BY 20Z WITH LIGHT E/NE
WINDS PREVAILING THROUGH THE EVENING AND OVERNIGHT. CLOUD
COVERAGE WILL INCREASE DURING THE OVERNIGHT BECOMING BKN TO
EVENTUALLY OVC AS THE NEXT STORM SYSTEM BRINGS WIDESPREAD LIGHT
TO MODERATE SHOWERS ON FRIDAY. ONSET OF LIGHT SHRA IS AROUND 12Z
WITH CIGS BEGINNING TO LOWER AND MINOR REDUCTIONS TO VIS.
MODERATE SHRA EXPECTED DURING THE LATE MORNING AND EARLY
AFTERNOON HOURS WITH MVFR TO IFR CIGS AND VIS LOOKING LIKELY,
ILLUSTRATED IN 18Z TAF. THREAT FOR TS IS VERY LOW AS CONVECTIVE
PARAMETERS DON'T SUPPORT MUCH IN TERMS OF CONVECTION AND
LIGHTNING. THAT SAID, EVEN THOUGH THE THREAT FOR TS IS LOW, IT'S
NOT ZERO. BUT FOR NOW, WITH LOW CONFIDENCE, THERE'S NO MENTION
OF TS IN TAF.
/OUTLOOK FOR KMSP/
SAT...VFR. WIND NE 5-10G20KTS.
SUN...VFR. WIND NE 5-10G20KTS.
MON...VFR. WIND E 5-10G15KTS.
MPX WATCHES/WARNINGS/ADVISORIES
MN...NONE.
WI...NONE.
DISCUSSION...JRB
AVIATION...LPR
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