663
FXUS63 KMPX 180546
AFDMPX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN
1246 AM CDT FRI SEP 18 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 /06Z TAFS THROUGH 12Z SATURDAY/
ISSUED AT 1237 AM CDT FRI SEP 18 2026
RAIN IS WORKING ITS WAY INTO SOUTHWESTERN MINNESOTA EARLY THIS
MORNING WITH MVFR CIGS ENCROACHING ON KMKT AND KRWF. RAIN
SHOULD BEGIN AT OUR WESTERN/SOUTHERN SITES BEFORE 12Z WITH
KSTC/KMSP FOLLOWING BY 14Z AND FINALLY OUR WISCONSIN TERMINALS
BY MID/LATE MORNING. MAINTAINED THE -TSRA MENTION FOR KMKT AND
ADDED KRWF FOR A FEW HOURS LATER THIS MORNING. PREVAILING LOW
END MVFR/IFR SEEMS PRETTY LIKELY THROUGH MUCH OF THE TAF PERIOD.
EAST WINDS MAY GUST TO AROUND 20-25KTS DURING THE AFTERNOON
BEFORE DIMINISHING AFTER 00Z. ONCE THE BULK OF THE RAIN COMES TO
AN END, IFR CIGS/VIS WILL PERSIST WITH FOG/DRIZZLE THROUGH THE
END OF THE FORECAST PERIOD.
KMSP...NO BIG CHANGES FROM THE PREVIOUS FORECAST. LEFT THUNDER
OUT AS THE BETTER ENVIRONMENT REMAINS TO THE SOUTH AND WEST.
/OUTLOOK FOR KMSP/
SAT...MVFR. CHC IFR. WIND NE 10-20 KTS.
SUN...VFR. WIND NE 10-20 KTS.
MON...VFR. WIND E 5-10G15 KTS.
MPX WATCHES/WARNINGS/ADVISORIES
MN...FLOOD WATCH FROM THIS EVENING THROUGH SATURDAY MORNING FOR
FREEBORN.
WI...NONE.
DISCUSSION...BORGHOFF/JRB
AVIATION...DYE
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