039
FXUS63 KDLH 121749
AFDDLH
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DULUTH MN
1249 PM CDT SUN APR 12 2026
KEY MESSAGES
- INCREASED THREAT FOR STRONG TO SEVERE STORMS ACROSS NORTHERN
MN AND THE SOUTH SHORE THIS AFTERNOON AND EVENING. A MARGINAL
RISK (1 OUT OF 5) IS NOW OUTLINED FOR PRIMARILY A HAIL THREAT
FROM 3PM TO 8PM.
- MORE SEVERE WEATHER POSSIBLE TUESDAY AFTERNOON AND EVENING
WITH LARGE HAIL IN EXCESS OF PING PONG BALL SIZE. DEPENDING
ON WHERE THE BOUNDARY SETS UP WE COULD SEE HEAVY RAINFALL
MOVING ACROSS THE REGION LEADING TO INCREASED FLOODING
CONCERNS ACROSS THE SOUTH SHORE AND THE ARROWHEAD.
DISCUSSION
ISSUED AT 302 AM CDT SUN APR 12 2026
CURRENT CONDITIONS:
BROAD WARM AIR ADVECTION CONTINUES OVER THE REGION THIS MORNING WITH
ISENTROPIC FORCING FOR ASCENT PRODUCING RAIN SHOWERS WITH SOME
EMBEDDED THUNDERSTORMS. THE THUNDERSTORMS ARE CONFINED TO THE TIP OF
A LOW LEVEL JET RUNNING INTO NW WI. STORMS WITHIN THIS AREA HAVE
REMAINED ELEVATED IN NATURE WITH BULK SHEAR OF AROUND 40 KTS. PAIRED
WITH MID LEVEL LAPSE RATE OF AROUND 7.5C/KM AND SOME UPDRAFT HELICITY
HAS LEAD TO SOME SMALL HAIL PRODUCTION. THE LOW LEVEL JET WILL
WEAKEN AND SHIFT OFF TO THE EAST IN THE LATTER MORNING HOURS
WITH RAIN CHANCES TAPERING OFF.
TODAY:
WARM AIR ADVECTION WILL CONTINUE TO OVERRUN THE AREA THROUGH THE DAY
AS A SURFACE LOW PRESSURE EJECTS OUT OF THE RED RIVER VALLEY INTO
NORTHERN MN. THIS SURGE OF WARMTH WILL LEAD TO HIGHS CLIMBING INTO
THE 70S ACROSS OUR SOUTH WITH COOLER TEMPERATURES INTO THE 40S AND
50S AS YOU GET CLOSER TO LAKE SUPERIOR. SOUTH TO SOUTHWEST FLOW
THROUGH MOST OF THE DAY WILL KEEP LOW CLOUDS ENGULFING THE REGION
AND MAY LEAD TO DENSE FOG THROUGH THE MORNING, ESPECIALLY FOR AREAS
NEAR LAKE SUPERIOR.
RAIN AND THUNDERSTORM COVERAGE REMAINS CONTESTED AMONG THE CAMS
FOR TODAY. THE CONTINUED ISENTROPIC LIFTING FOR ASCENT WILL BE
PRESENT THROUGH THE DAY WHICH WILL MAINTAIN SOME LOW TO MEDIUM
POPS. THE AFOREMENTIONED SURFACE LOW WILL END UP IN PHASE WITH
AN UPPER LEVEL TROUGH AROUND PEAK HEATING OVER NORTHERN MN. THIS
SEEMS TO BE THE BEST CHANCE FOR SOME STRONG TO SEVERE STORMS TO
DEVELOP AS THIS CORRIDOR WILL HAVE ADEQUATE INSTABILITY AND
SHEAR. SOUNDING PROFILES WOULD SUGGEST THE WARM NOSE IN PLACE
WOULD LIKELY LEAD TO ELEVATED THUNDERSTORMS WITH HAIL BEING THE
MAIN THREAT. BUT THERE IS A SMALL WINDOW FOR SOME OF THESE
STORMS TO BECOME SURFACE BASED ALONG THE FRONTAL BOUNDARY. IF
STORMS DO MANAGE TO BECOME SURFACE BASED THEN ALL MODES OF
SEVERE WILL BE IN PLAY. MAIN THREAT WINDOW WILL BE BETWEEN 3PM
AND 8PM.
MONDAY:
ANOTHER ACTIVE DAY WILL BE ON TAP AS ANOTHER LOW PRESSURE INFRINGES
ON THE NORTHLAND OUT OF THE CENTRAL PLAINS. A WARM FRONT WILL SPAN
WEST TO EAST AND SLOWLY MARCH NORTH INTO OUR SOUTHERN COUNTIES IN
THE AFTERNOON WITH DEWPOINTS OF 60F KNOCKING ON OUR DOOR STEP. THIS
CORRIDOR OF HIGH INSTABILITY WILL HAVE BULK SHEAR VALUES OF 50-60
KTS TO HELP SUSTAIN SUPERCELL DEVELOPMENT. MEAN STORM FLOW IS
EXPECTED TO BE OUT OF THE SOUTHWEST LEADING TO SOME DISCRETE CELLS
INITIALLY THAT WILL CONGEAL INTO A LINEAR MODE LATER INTO THE EVENT.
HOWEVER, EVOLUTION OF THE STORM SYSTEM REMAINS A POINT OF DEBATE
AMONGST THE CAMS AS THEY CONTINUE TO FLIP FLOP WITH BOUNDARY
LOCATION. IF STORMS DO MANAGE TO DEVELOP AND MOVE OFF THIS BOUNDARY
INTO OUR REGION THEN HAIL LOOKS TO BE THE PRIMARY THREAT WITH WIND
BEING THE SECONDARY THREAT. LHP VALUES OF 16 COMBINED WITH STEEP MID
LEVEL LAPSE RATES OF 8.5C/KM WILL BE ABLE TO GENERATE SOME LARGE
HAIL OF AT LEAST GOLF BALL SIZE IF NOT HIGHER. ONE OF THE OTHER BIG
QUESTIONS WILL BE THE PROGRESSION OF THE LOW AS IT WILL DRAG THE
FRONTAL BOUNDARIES EITHER INTO OUR CWA OR SOUTH. IF IT MANAGES TO
PUSH NORTH THEN WE COULD SEE SOME HEFTY RAIN RATES INTO NW WI WHICH
MAY PROMPT SOME FLOODING CONCERNS DEPENDING ON HOW MUCH MOISTURE AND
SNOWMELT WE RECORD FOR TODAY.
TUESDAY:
NOT COMPLETELY QUIET ON TUESDAY BUT LESS ACTIVE THEN SUNDAY AND
MONDAY. AN UPPER LEVEL TROUGH SLIDES IN FROM THE NORTHERN PLAINS
TUESDAY MORNING WHICH WILL PRODUCE SOME LIGHT RAIN. THIS SYSTEM DOES
NOT HAVE MUCH INSTABILITY TO WORK WITH SO NOT EXPECTING SEVERE
WEATHER AT THIS TIME. WEAK ELEVATED INSTABILITY MAY LEAD TO A FEW
RUMBLES OF THUNDER THOUGH. TUESDAY NIGHT IS WHEN WE GET A BIT OF
DIVERGENCE IN MODEL DEPICTION WITH THE DETERMINISTIC 00Z RUNS
LARGELY KEEPING SURFACE HIGH PRESSURE OVER THE NORTHLAND AND
SHUNTING ACTIVITY TO OUR SOUTH. BUT A LOOK AT THE AIGEFS AND ECAIFS
SHOW A SURFACE LOW MOVING ACROSS THE MIDWEST AND HAVING ITS NORTHERN
PRECIPITATION SHIELD CROSSING INTO THE NORTHLAND TUESDAY NIGHT.
MIDWEEK INTO THE EXTENDED FORECAST:
OUR PERPETUAL ACTIVE PATTERN HAS NO QUIT IN SIGHT AS ADDITIONAL
SYSTEMS WORK THEIR WAY THROUGH THE MIDWEST WEDNESDAY THROUGH THE
WEEKEND. DETAILS AND PLACEMENTS OF THE MAIN SYNOPTIC DRIVERS REMAIN
IN FLUX BUT THE LATE FRIDAY INTO THE WEEKEND SYSTEM LOOKS TO CARRY
SOME COLD AIR ON ITS BACKSIDE. THIS COULD REINTRODUCE SOME SNOW FALL
BACK ACROSS THE NORTHLAND WITH LIGHT ACCUMULATIONS FRIDAY NIGHT AS
LOWS DROP INTO THE 20S. ANY SNOW THAT DOES MANAGE TO FALL WILL NOT
LINGER LONG AS WE WARM BACK INTO THE UPPER 30S AND LOW 40S FOR
SATURDAY.
AVIATION /18Z TAFS THROUGH 18Z MONDAY/
ISSUED AT 1242 PM CDT SUN APR 12 2026
WARM FRONT MOVED ACROSS THE AREA THIS AFTERNOON AND IS
TRIGGERING WIDESPREAD RAIN SHOWERS AND A FEW THUNDERSTORMS IN
NORTHERN MINNESOTA. PREVAILING SOUTHWESTERLY WINDS WILL OCCUR
FOR A 6 TO 9 HOUR PERIOD UNDER THIS WARM SECTOR AHEAD OF AN
INCOMING COLD FRONTAL PASSAGE WEST TO EAST THIS EVENING. AN
ISOLATED SEVERE THUNDERSTORM LATE THIS AFTERNOON THROUGH THIS
EVENING CANNOT BE RULED OUT FOR HIB/INL AND INTO THE ARROWHEAD.
FOG IS LIKELY TO AGAIN SETUP TONIGHT, WITH POSSIBLY LINGERING
DENSE FOG IN THE ARROWHEAD STILL FROM TODAY. WINDS SHIFT TO
NORTHERLY AND BECOME LIGHT TONIGHT FROM 06-12Z. GUIDANCE IS
POINTING TOWARDS LIFTING CEILINGS FROM 14-17Z TOMORROW AHEAD OF
THE NEXT ROUND OF STRONG TO POSSIBLY SEVERE THUNDERSTORMS FOR
AREAS SOUTH OF US HWY 2 AFTER 20Z MONDAY.
MARINE /FOR NEARSHORE WATERS OF WESTERN LAKE SUPERIOR/
ISSUED AT 302 AM CDT SUN APR 12 2026
ACTIVE WEATHER PATTERN CONTINUES FOR LAKE SUPERIOR WITH MULTIPLE
CHANCES FOR SHOWERS AND STORMS. A LOW PRESSURE MOVING ACROSS
NORTHERN MN TODAY WILL SEE AN INCREASE IN SOUTHERLY WINDS THIS
AFTERNOON ALONG THE SOUTH SHORE THAT COULD BRIEFLY LEAD TO A FEW
GUSTS OF AROUND 25KS FROM. BUT NOT A LOT OF CONFIDENCE THAT THIS
WILL BLEED OVER INTO THE NEARSHORE WATERS, BEST TIMING WOULD LIKELY
BE BETWEEN 3-6PM. A COLD FRONT WILL CROSS OVER THE LAKE THIS
EVENING WITH WIND DIRECTIONS CHANGING TO OUT OFF THE WEST AND
SOUTHWEST BY MONDAY MORNING. ANOTHER DIRECTION SHIFT TO OUT OF THE
NORTHEAST AS A LOW PRESSURE MOVES ACROSS MN IN THE AFTERNOON, THIS
MAY LEAD TO SOME FUNNELING OF THE WINDS AT THE HEAD OF THE LAKE AND
WARRANT SOME SMALL CRAFT ADVISORIES
FOR THE OPEN WATER DISCUSSION, REFER TO THE NWS MARQUETTE AREA
FORECAST DISCUSSION AT WEATHER.GOV/MQT.
FIRE WEATHER
ISSUED AT 302 AM CDT SUN APR 12 2026
NO FIRE WEATHER CONCERNS AT THIS TIME. ACTIVE WEATHER PATTERN
REMAINS IN PLACE WITH MULTIPLE ROUNDS OF SHOWERS AND STORMS KEEPING
CONDITIONS MOIST THROUGH MIDWEEK.
SEE THE FIRE WEATHER FORECAST PRODUCT FOR A MORE THOROUGH
BREAKDOWN OF FIRE WEATHER CONDITIONS.
HYDROLOGY
ISSUED AT 345 AM CDT SUN APR 12 2026
NO CHANGES TO THE FLOOD WATCH FOR BAYFIELD, ASHLAND, AND IRON
COUNTIES IN WISCONSIN FOR THIS EVENING THROUGH EARLY WEDNESDAY
MORNING. THE WATCH REMAINS MEDIUM CONFIDENCE AS IT WILL BE LESS THE
TRADITIONAL SENSE FOR FLASH FLOODING POTENTIAL AND MORE INTO THE
POTENTIAL FOR AROUND 1-2" OF RAIN OVER SEVERAL DAYS COMBINED WITH
THE POTENTIAL FOR 1-5 INCHES OF SNOW WATER TO MELT OUT OF THE
REMAINING SNOWPACK. GIVEN THE CONVECTIVE NATURE OF THE
PRECIPITATION, SOME POCKETS OF LOCALLY HIGHER AND LOWER RAINFALL
TOTALS WILL BE POSSIBLE. THE PRECIPITATION FROM THIS MORNING WILL
SET THE STAGE FOR SUBSEQUENT ROUNDS OF FLOODING POTENTIAL. HOWEVER,
THE QPF TRENDS CONTINUE TO SHIFT FURTHER SOUTHEAST WITH EACH MODEL
SUBSEQUENT MODEL RUN. THE MAIN THREAT STILL LOOKS TO BE MONDAY NIGHT
AS A LOW PRESSURE SYSTEM MOVES ACROSS MN. A FEW OF THE DETERMINISTIC
MODELS ARE PAINTING 0.50-1.00" WITHIN A 12 HR PERIOD.
WE WILL STILL NEED TO MONITOR FOR RIVER RISE/FLOOD CONCERNS ALONG
THE NORTH SHORE AS WELL GIVEN THE DEEPER SNOWPACK TO 12-24"+ OF SNOW
DEPTH AND SNOW WATER EQUIVALENTS OF 5-7"+ THERE.
HOWEVER, THE TREND HAS BEEN FOR THE HEAVIEST RAIN TO REMAIN SOUTH OF
THE NORTH SHORE. ADDITIONALLY, DESPITE TEMPERATURES FORECAST TO BE
ABOVE FREEZING FOR SEVERAL DAYS IN A ROW, LAKE SUPERIOR WILL KEEP
THE NORTH SHORE HIGH TEMPERATURES ABOUT 10-20F COLDER AND LOW
TEMPERATURES 5-15F COLDER THAN AREAS FARTHER INLAND. THIS SHOULD
SLOW THE SNOWMELT PROCESS THERE RELATIVE TO THE SOUTH SHORE. SHOULD
PRECIPITATION FORECASTS AND/OR TEMPERATURE FORECASTS INCREASE FOR
THE NORTH SHORE FOR TONIGHT THROUGH WEDNESDAY, THEN FLOOD HEADLINES
MAY BE NEEDED.
AS FOR RIVER AND STREAM CONCERNS, THE HIGHEST POTENTIAL FOR MINOR
FLOODING REMAINS WITH THE TYLER FORKS NEAR MELLEN, WHICH COULD SEE
MINOR FLOODING BY LATE MONDAY OR EARLY TUESDAY DEPENDING ON HOW
HEAVY THE FIRST COUPLE ROUNDS OF RAIN ARE. THE BAD RIVER AND NEMADJI
RIVERS ALSO HAVE SOME POTENTIAL TO RISE INTO ACTION STAGE IN THE
MONDAY TO TUESDAY TIMEFRAME DEPENDING ON HEAVY RAIN LOCATIONS AND
AMOUNTS.
DLH WATCHES/WARNINGS/ADVISORIES
MN...DENSE FOG ADVISORY UNTIL 1 AM CDT MONDAY FOR MNZ020-021.
WI...FLOOD WATCH THROUGH WEDNESDAY MORNING FOR WIZ002>004.
MARINE...DENSE FOG ADVISORY UNTIL 1 AM CDT MONDAY FOR LSZ140>145-148.
DENSE FOG ADVISORY UNTIL 1 AM CDT MONDAY FOR LSZ142.
DENSE FOG ADVISORY UNTIL 10 AM CDT MONDAY FOR LSZ146-147-150.
DISCUSSION...BRITT
AVIATION...NLY
MARINE...BRITT
FIRE WEATHER...BRITT
HYDROLOGY...ROTHSTEIN/BRITT
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