822
FXUS63 KDLH 172341
AFDDLH
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DULUTH MN
641 PM CDT THU APR 17 2025
KEY MESSAGES
- WIDESPREAD MODERATE TO VERY LOCALLY HEAVY RAINFALL THIS
EVENING BECOMES MORE LOCALIZED LATE TONIGHT INTO FRIDAY.
- WINTRY MIX MAY RETURN TO PORTIONS OF THE NORTHLAND SUNDAY
NIGHT INTO MONDAY WITH MORE RAINFALL MIDDLE OF NEXT WEEK.
DISCUSSION
ISSUED AT 327 PM CDT THU APR 17 2025
SURFACE LOW PRESSURE IN WESTERN MINNESOTA AND A SUPPORTING
SHORTWAVE IN THE MID-LEVELS IS INCREASING RAIN SHOWER COVERAGE
AND ISOLATED THUNDERSTORMS OVER THE NORTHLAND THIS AFTERNOON.
THE INITIAL BAND OF THUNDERSTORMS WILL LIFT INTO THE
INTERNATIONAL BORDERLANDS OVER THE NEXT TWO HOURS AHEAD OF THE
NEXT ROUND OF PRECIP ENTERING THE REGION FROM THE WEST. EXPECT
ANYWHERE FROM 0.1 TO 0.5 INCHES OF ADDITIONAL RAINFALL IN
NORTH-CENTRAL THIS EVENING. A RIBBON OF INSTABILITY AND
ELEVATED LAPSE RATES MOVES INTO THE AITKIN COUNTY, I-35 AND INTO
INLAND NORTHWEST WISCONSIN REGION OVER THE NEXT COUPLE OF HOURS
AS SEEN ON HIGH-RES ENVIRONMENTAL GUIDANCE. THE PRIMARY THREAT
WOULD BE ADDITIONAL SMALL HAIL FROM THESE STORMS THROUGH SUNSET
TODAY AS THE STRONGER STORMS DROP SOUTHEAST OF THE REGION INTO
WEST- CENTRAL WISCONSIN. ANYWHERE FROM 0.5 TO 1.25 INCHES OF
ADDITIONAL RAINFALL IS FORECAST FOR THIS AREA THAT SEES A BAND
OF HEAVIER RAINFALL SET UP INTO EARLY TONIGHT.
THE HEAVY-RAIN SUPPORTING PLUME OF 1.1 INCHES PRECIPITABLE
WATER VALUES QUICKLY EXITS THE REGION AS SHIFT TO NORTHERLY
BEHIND THE SURFACE TO LOW PRESSURE SYSTEM LIFTING INTO NORTHWEST
WISCONSIN AND THE UPPER GREAT LAKES. EXPECT CONTINUED RAIN
SHOWERS INTO SATURDAY AS THE MID-LEVEL SHORTWAVE MOVES ACROSS
NORTHWEST ONTARIO AND LIFTS ADDITIONAL IMPULSES THROUGH THE
REGION. INSTABILITY WILL BE HIGHLY LIMITED THOUGH FRIDAY SO NO
THUNDERSTORMS ARE FORECAST WITHIN THIS RAIN SHOWER FAVORED
ENVIRONMENT. THE RAIN SHOWER CHANCES TAPER QUICKLY FRIDAY
AFTERNOON AND EARLY EVENING AS HIGH PRESSURE SETS UP FRIDAY
NIGHT. THIS HIGH PRESSURE WILL FEATURE A WARMING TREND FROM THE
40S SATURDAY INTO THE 50S SUNDAY. WITH THIS DRY AIR IN PLACE
SUNDAY AND WARMING TEMPERATURES, RELATIVE HUMIDITY IS AGAIN
FORECAST TO DROP INTO THE 25-35% RANGE AS SOUTHEAST WINDS
INCREASE INTO THE AFTERNOON. SUNDAY WILL HAVE TO BE MONITORED
FOR POSSIBLE NEAR-CRITICAL FIRE WEATHER CONDITIONS THAT DAY.
LOW PRESSURE FROM SOUTHWEST TO NORTHEAST THROUGH THE CENTRAL
MIDWEST KEEPS A 30-60% CHANCE OF A WINTRY MIX IN THE FORECAST
FOR SUNDAY NIGHT INTO MONDAY MORNING. ANY SNOW ACCUMULATIONS
ARE VERY LIKELY (60-80% CHANCE) TO BE LESS THAN 1 INCH MAINLY IN
NORTHEAST MINNESOTA. THE EXCEPTION IS A 20-40% CHANCE OF AROUND
2 INCHES IN THE ARROWHEAD AND SOUTH SHORE, WITH A 10-20% CHANCE
OF GREATER THAN 4 INCHES IN THE ARROWHEAD.
PRECIPITATION QUICKLY DECREASE MONDAY AFTERNOON FROM WEST TO
EAST TO RETURN TO A SEASONABLE TEMPERATURE AND DRY PERIOD FOR
MONDAY NIGHT INTO TUESDAY. MULTIPLE VORT MAXES ROTATING THROUGH
A DEEP OPEN WAVE MIDDLE OF NEXT WEEK KEEP THE ACTIVE PATTERN IN
PLACE FOR THE NORTH-CENTRAL U.S. TUESDAY INTO WEDNESDAY.
AVIATION /00Z TAFS THROUGH 00Z SATURDAY/
ISSUED AT 635 PM CDT THU APR 17 2025
WIDESPREAD RAIN SHOWERS WITH A FEW EMBEDDED THUNDERSTORMS WILL
CONTINUE ACROSS NORTHEAST MINNESOTA AND NORTHWEST WISCONSIN THIS
EVENING AND TONIGHT. CEILINGS WILL LOWER TO IFR TONIGHT FOR
MOST LOCATIONS, WITH AREAS OF FOG ALSO LIKELY. RAIN SHOWERS WILL
CONTINUE ACROSS NORTHWEST WISCONSIN AND BACK INTO THE I-35
CORRIDOR INTO FRIDAY. CEILINGS WILL BE SLOW TO LIFT FROM WEST TO
EAST ACROSS THE REGION THROUGH THE DAY ON FRIDAY, WITH IFR
CONDITIONS LIKELY FOR MOST OF THE DAY ACROSS NORTHWEST
WISCONSIN.
MARINE /FOR NEAR SHORE WATERS OF WESTERN LAKE SUPERIOR/
ISSUED AT 247 PM CDT THU APR 17 2025
NORTHEAST WIND GUSTS OF UP TO 25 KNOTS AND WAVE HEIGHTS OF UP
TO 4 FEET ARE POSSIBLE FROM SILVER BAY TO SAND BAY. A SMALL
CRAFT ADVISORY REMAINS IN EFFECT FOR THE HEAD OF THE LAKE
THROUGH LATE THIS EVENING. THUNDERSTORMS THROUGH THIS EVENING
MAY BRING IN SOME SMALL HAIL AND LIGHTNING. DENSE FOG IS
EXPECTED ALONG THE SOUTH SHORE OF LAKE SUPERIOR AND WILL EXPAND
TO THE NORTH SHORE LATER TONIGHT. MARINE DENSE FOG ADVISORIES
HAVE BEEN ISSUED FOR THIS EXPECTED VERY LOW VISIBILITIES IN THE
NEARSHORE WATERS TONIGHT. EARLY TONIGHT, WINDS WILL SHIFT FROM
THE NORTHWEST AND WILL WEAKEN THROUGHOUT THE DAY TOMORROW. DENSE
MARINE FOG IS FORECAST TO LINGER INTO MID TO LATE MORNING
TOMORROW AS THE VERY LOW LEVELS START TO DRY OUT AND CLEAR OUT
BY EARLY AFTERNOON.
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...DENSE FOG ADVISORY UNTIL 10 AM CDT FRIDAY FOR LSZ121-144>148-
150.
DENSE FOG ADVISORY FROM 10 PM THIS EVENING TO 1 PM CDT FRIDAY
FOR LSZ140>143.
SMALL CRAFT ADVISORY UNTIL 10 PM CDT THIS EVENING FOR
LSZ143>146.
DISCUSSION...NLY
AVIATION...PA
MARINE...NLY
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