040
FXUS63 KDLH 142022
AFDDLH
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DULUTH MN
322 PM CDT THU AUG 14 2025
KEY MESSAGES
- STRONG TO SEVERE THUNDERSTORMS WILL BE POSSIBLE IN FAR NORTH-CENTRAL
MINNESOTA THIS EVENING INTO TONIGHT, WITH LARGE HAIL TO 1"
BEING THE PRIMARY HAZARD.
- ANOTHER ROUND OF SEVERE THUNDERSTORMS WILL BE CONDITIONALLY POSSIBLE
LATE FRIDAY, MOST LIKELY IN NORTHWEST WISCONSIN. LARGE HAIL
TO 1.5" AND DAMAGING WINDS TO 70 MPH ARE POTENTIAL HAZARDS.
- AN ACTIVE PATTERN PERSISTS THROUGH THE WEEKEND WITH MULTIPLE
ROUNDS FOR RAIN BEFORE DRIER WEATHER RETURNS ON TUESDAY INTO
WEDNESDAY.
DISCUSSION
ISSUED AT 322 PM CDT THU AUG 14 2025
AN ACTIVE PATTERN IS EXPECTED OVER THE NEXT SEVERAL DAYS AS
VERTICALLY-STACKED LOW PRESSURE, CURRENTLY LOCATED OVER NORTHERN
MANITOBA, SLOWLY PROPAGATES EASTWARD AND A SERIES OF SHORTWAVE
TROUGHS AT 500MB MOVE THROUGH. WIDELY SCATTERED SHOWERS AND ISOLATED
THUNDERSTORMS HAVE BEEN OBSERVED THIS AFTERNOON ACROSS THE
NORTHLAND, BEING FORCED FROM A WEAK AMPLITUDE SHORTWAVE AND
ISENTROPIC ASCENT AHEAD OF A WARM FRONT LIFTING TOWARDS THE CWA.
OVERALL IMPACTS THIS AFTERNOON WILL BE MINIMAL WITH SEVERE
THUNDERSTORMS NOT EXPECTED.
A COLD FRONT ASSOCIATED WITH THE VERTICALLY-STACKED LOW PRESSURE
WILL BEGIN TO ENTER THE FAR NORTHWESTERN CWA THIS EVENING INTO
TONIGHT. A LINE OF THUNDERSTORMS CURRENTLY DEVELOPING ALONG THIS
COLD FRONT IN CENTRAL NORTH DAKOTA AND SOUTH-CENTRAL MANITOBA WILL
MOVE EASTWARD THIS AFTERNOON AND EVENING TOWARDS NORTH-CENTRAL
MINNESOTA. THE EXPECTATION IS THAT THESE THUNDERSTORMS WILL BE
DECAYING BY THE TIME THEY REACH THE CWA, AS THE BEST
THERMODYNAMIC ENVIRONMENT WILL BE FOUND FARTHER SOUTH AND WEST
OF OUR AREA. HOWEVER, LINGERING MUCAPE VALUES OF 1000-2000 J/KG
COMBINED WITH MARGINALLY FAVORABLE 0-6KM BULK SHEAR OF 20-25
KNOTS WILL POTENTIALLY BE ENOUGH TO SUSTAIN STRONG TO SEVERE
THUNDERSTORMS THIS EVENING INTO TONIGHT. ANY SEVERE CONVECTION
TODAY INTO TONIGHT WILL BE MOST LIKELY IN KOOCHICHING COUNTY,
WITH THE POTENTIAL RAPIDLY DECREASING FARTHER EAST. THE PRIMARY
CONCERN IS LARGE HAIL UP TO 1", WITH DAMAGING WINDS BEING A
LESSER CONCERN DUE TO THESE NOCTURNAL STORMS LIKELY BEING
ELEVATED. EXPECT SEVERE POTENTIAL FOR DIMINISH LATE TONIGHT INTO
EARLY FRIDAY MORNING.
AS THE COLD FRONT CONTINUES TO ENTER THE CWA, IT WILL BEGIN STALLING
AND TURNING INTO A STATIONARY FRONT ACROSS THE SOUTHERN HALF OF THE
CWA. AMPLE MOISTURE ADVECTION ON FRIDAY FROM SOUTHERLY WINDS
ALOFT ARE EXPECTED TO INCREASE SFC DEWPOINTS INTO THE 70S ALONG
AND SOUTH OF THE IRON RANGE. THESE MUGGY DEWPOINTS, WHEN
COMBINED WITH MODERATELY STEEP MID-LEVEL LAPSE RATES OF 7-8
DEGC/KM, HAVE THE POTENTIAL TO BUILD AN IMPRESSIVE AMOUNT OF
MUCAPE OF 2000-3000+ J/KG. THE MOST FAVORABLE THERMODYNAMIC
CONDITIONS TOMORROW ARE EXPECTED TO BE OVER NORTHWEST WI,
ESPECIALLY ALONG AND SOUTH OF WI STATE HIGHWAY 77.
WHILE INSTABILITY WILL POTENTIALLY BE VERY FAVORABLE, IT IS
WORTH NOTING THAT THE AVAILABILITY OF THIS CAPE WILL BE HEAVILY
DEPENDENT ON THE AMOUNT OF CLEARING THAT CAN OCCUR. CAM MODEL
SOUNDINGS SHOW A WARM NOSE AROUND THE 850-750MB LAYER, WHICH COULD
RESULT IN CONVECTION EITHER LARGELY BEING ELEVATED OR CAPPED
ENTIRELY IF CLOUD COVER BECOMES PERSISTENT. MEAN CLOUD COVER FROM
THE 12Z HREF SHOWS THAT SOME CLEARING IS POSSIBLE, BUT UNCERTAINTY
REMAINS HIGH. PROVIDED THAT THE CAP CAN BE OVERCOME, WIND SHEAR IS
FAVORABLE WITH 40-50 KNOTS OF 0-6KM BULK SHEAR, WHICH WILL HELP
PROVIDE ORGANIZATION TO A POTENTIAL MCS MOVING ACROSS NORTHERN WI.
THE STORM PREDICTION CENTER UPGRADED PORTIONS OF THE WI CWA TO A
SLIGHT RISK FOR TOMORROW DUE TO THIS POTENTIAL FOR AN MCS.
HOWEVER, UNCERTAINTY STILL EXISTS DEPENDING ON HOW MUCH CLEARING
CAN OCCUR. IN ADDITION, THE 500MB SHORTWAVE TROUGH THAT WILL BE
HELPING TO PROVIDE SYNOPTIC LIFT WILL BE WEAK AMPLITUDE, WHICH
WILL LIMIT THE OVERALL DYNAMIC UPWARD FORCING. IF STORMS ARE
ABLE TO INITIATE, LARGE HAIL UP TO 1.5" WILL BE POSSIBLE FROM
INITIALLY DISCRETE CONVECTION BEFORE THE PRIMARY HAZARD
TRANSITIONS TO DAMAGING WINDS TO 70 MPH AS AN MCS DEVELOPS.
OVERALL, TOMORROW AFTERNOON AND EVENING WILL BE A PERIOD TO KEEP
A CLOSE EYE ON. IN ADDITION TO STORMS, VERY WARM TEMPERATURES
ARE EXPECTED ON FRIDAY, WITH HEAT INDICES FOR SOUTHERN PORTIONS
OF THE CWA BUILDING TO THE LOW TO MID 90S.
FOLLOWING FRIDAY'S SEVERE THUNDERSTORM CHANCES, ADDITIONAL ROUNDS OF
SHOWERS AND THUNDERSTORMS ARE POSSIBLE ON SATURDAY, SUNDAY, AND
MONDAY AS SEVERAL SHORTWAVES PROPAGATE THROUGH THE AREA. SOUTHERN
PORTIONS OF THE CWA ARE HIGHLIGHTED IN A SLIGHT RISK (15% CHANCE)
FOR EXCESSIVE RAINFALL FROM FRIDAY-SUNDAY, WITH PONDING AND ISOLATED
FLOODING POSSIBLE. HOWEVER, THE OVERALL CONCERN FOR FLOODING IS LOW
AS 1-3" OF RAINFALL WILL BE OCCURRING OVER A PROLONGED PERIOD. IN
ADDITION, MUCH OF THIS RAINFALL IS FORECAST TO OCCUR OVER AREAS THAT
HAVE BEEN SEEING BELOW-NORMAL PRECIPITATION WHICH REDUCES THE FLOOD
RISK.
LOOKING AHEAD TO NEXT WEEK, DRIER CONDITIONS WILL BE POSSIBLE ON
TUESDAY AND WEDNESDAY AS A RIDGE BUILDS OVER THE CENTRAL CONUS.
TEMPERATURES AFTER FRIDAY WILL BEGIN TO MODERATE TO MORE
SEASONABLE LEVELS, WITH BELOW-NORMAL HIGH TEMPS LIKELY ON SUNDAY
AS STRONG NORTHEAST WINDS ADVECT COOLER AIR INLAND FROM LAKE
SUPERIOR.
AVIATION /18Z TAFS THROUGH 18Z FRIDAY/
ISSUED AT 1234 PM CDT THU AUG 14 2025
LARGELY VFR CIG HEIGHTS ARE EXPECTED THIS AFTERNOON, WITH THE
EXCEPTION BEING MVFR CIGS AROUND THE BRAINERD LAKES AREA. ISOLATED
SHOWERS AND THUNDERSTORMS HAVE DEVELOPED IN NORTHEAST MN THIS
AFTERNOON AND ARE EXPECTED TO WEAKEN AS THEY PROPAGATE NORTH.
ADDITIONAL SHOWERS AND THUNDERSTORMS WILL BE POSSIBLE OVERNIGHT,
ALONG WITH MVFR TO IFR FOG DEVELOPMENT. CONFIDENCE IN FOG TONIGHT IS
HIGHEST FOR KHIB, WITH LESSER CONFIDENCE FOR KINL AND KBRD.
CONDITIONS GENERALLY IMPROVE TO VFR TOMORROW MORNING AS SKIES BEGIN
TO CLEAR. SOUTHERLY WINDS WILL OCCASIONALLY BE GUSTY THROUGH THE
PERIOD.
MARINE /FOR NEAR SHORE WATERS OF WESTERN LAKE SUPERIOR/
ISSUED AT 322 PM CDT THU AUG 14 2025
EAST TO NORTHEAST WINDS ARE EXPECTED THIS AFTERNOON AND EVENING,
GUSTING TO 20 KNOTS FOR MUCH OF WESTERN LAKE SUPERIOR. NEAR THE TWIN
PORTS, HIGHER WINDS UP TO 25 KNOTS HAVE BEEN OBSERVED. THEREFORE, A
SMALL CRAFT ADVISORY HAS BEEN ISSUED UNTIL 10 PM THIS EVENING.
ISOLATED SHOWERS AND THUNDERSTORMS WILL BE POSSIBLE THIS AFTERNOON
INTO TONIGHT AS A COLD FRONT APPROACHES THE LAKE. LOOKING AHEAD, THE
PATTERN ON SUNDAY FAVORS AT LEAST SMALL CRAFT ADVISORY CONDITIONS.
HOWEVER, THERE IS A 40-50% CHANCE FOR GALE-FORCE WIND GUSTS ON
SUNDAY ACROSS A LARGE PORTION OF LAKE SUPERIOR. IF THIS TREND HOLDS,
A GALE WATCH MAY BE NEEDED HEADING INTO THE WEEKEND.
FOR THE OPEN WATER DISCUSSION, REFER TO THE NWS MARQUETTE AREA
FORECAST DISCUSSION AT WEATHER.GOV/MQT.
DLH WATCHES/WARNINGS/ADVISORIES
MN...NONE.
WI...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 10 PM CDT THIS EVENING FOR LSZ144-
145.
DISCUSSION...UNRUH
AVIATION...UNRUH
MARINE...UNRUH
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