968  
FXUS63 KDLH 172027  
AFDDLH  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE DULUTH MN  
327 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 /18Z TAFS THROUGH 18Z FRIDAY/
 
 
ISSUED AT 1241 PM CDT THU APR 17 2025  
 
WIDELY SCATTERED THUNDERSTORMS BUILD INTO THE REGION FROM  
SOUTHWEST TO NORTHEAST TODAY. EXPECT GUSTY AND ERRATIC WINDS AT  
TERMINALS NEAR AND RIGHT UNDER ANY THUNDERSTORMS THROUGH 03Z  
THIS EVENING. OFF-AND-ON RAIN SHOWERS CONTINUE INTO THE  
OVERNIGHT HOURS AS CEILINGS LOWER AND WINDS SHIFT NORTHERLY.  
AREAS OF FOG ARE LIKELY TO DEVELOP TONIGHT AND MAY CREATE SOME  
IFR TO LIFR VISIBILITY.  
 

 
   
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...SMALL CRAFT ADVISORY UNTIL 10 PM CDT THIS EVENING FOR  
LSZ143>146.  
 

 
 

 
 
DISCUSSION...NLY  
AVIATION...NLY  
MARINE...IGS/NLY  
 
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