171
FXUS63 KDLH 132340
AFDDLH
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DULUTH MN
640 PM CDT WED AUG 13 2025
KEY MESSAGES
- CHANCES FOR SHOWERS AND STORMS RETURN THURSDAY MORNING AND
CONTINUE INTO THE WEEKEND. SOME STORMS MAY BE STRONG TO SEVERE
THURSDAY NIGHT AND FRIDAY.
- STRONG EASTERLY WINDS SUNDAY, ESPECIALLY FOR LAKE SUPERIOR
SHORELINES.
- HAZARDOUS MARINE CONDITIONS VERY LIKELY SUNDAY FOR SMALL
VESSELS, WITH THE POSSIBILITY FOR DANGEROUS RIP CURRENTS
CREATING A HIGH SWIM RISK FOR LAKE SUPERIOR BEACHES TOO.
DISCUSSION
ISSUED AT 300 PM CDT WED AUG 13 2025
DAYTIME DIURNAL CUMULUS CLOUDS AND SEASONABLE TEMPERATURES
CREATE A NICE DAY TODAY IN THE NORTHLAND. ZONAL MID-LEVEL FLOW
ALOFT PERSISTS TONIGHT AS A SOUTHERLY LOW-LEVEL JET BUILDS
OVERHEAD IN THE UPPER MIDWEST. THE ASSOCIATED MOISTURE PLUME
WITH A WEAK VORTICITY MAXIMA CREATE A 20-40% CHANCE OF LIGHT
RAINFALL IN THE NORTHLAND BEGINNING EARLY THURSDAY MORNING FIRST
IN THE BRAINERD AND LEECH LAKE AREA. LIMITED INSTABILITY WILL
KEEP CLOUD-TO-CLOUD THUNDER CHANCES LIMITED TO MAINLY NORTH-
CENTRAL MINNESOTA FOR MUCH OF TOMORROW UNTIL THE AFTERNOON
HOURS. MOST PLACES IN NORTHERN MINNESOTA ARE EXPECTED TO SEE
LESS THAN A QUARTER-INCH TOMORROW, BUT A FEW ISOLATED HALF-INCH
SPOTS CANNOT BE RULED OUT.
AS DEEP LOW PRESSURE OVER THE SOUTHERN CANADIAN PRAIRIES DRAPES
A WARM FRONT FROM WEST TO EAST OVER THE NORTHLAND, A BOUT OF
WARM AIR ADVECTION SETS UP THURSDAY NIGHT INTO FRIDAY. ALONG
THIS WARM FRONT, A PERIOD OF SEVERE WEATHER IS POSSIBLE FOR
MAINLY THE WESTERN HALF OF MINNESOTA, BUT A FEW STRONG TO
ISOLATED SEVERE STORMS CANNOT BE RULED OUT INTO NORTH-CENTRAL
MINNESOTA THROUGH FRIDAY MORNING.
A FRONTAL BOUNDARY WILL STALL OUT FRIDAY DAYTIME OVER THE UPPER
MIDWEST AND LEAD TO HEAVY RAINFALL CHANCES FRIDAY EVENING TO
SATURDAY MORNING IN THE REGION, HIGHEST SOUTH OF THE IRON RANGE
IN NORTHERN MINNESOTA AND ACROSS ALL OF NORTHWEST WISCONSIN.
DAMAGING WINDS WOULD ALSO BE A CONCERN IN THIS FRIDAY PM TIME
PERIOD. ANY CONVECTION EARLIER IN THE DAYTIME IS LIKELY TO BE
SUPPRESSED BY THAT STABLE WARM AIR LAYER IN THE LOW-LEVELS
CAPPING OFF THE SURFACE. DEPENDING ON THE PATTERN THAT SETS UP,
A STORM TOTAL 1-2 INCHES IS LIKELY FOR SOME LOCATIONS IN CENTRAL
MINNESOTA TO WESTERN WISCONSIN.
AS THE LOW PRESSURE LIFTS NORTHEASTWARD INTO THE HUDSON BAY AND
TRAILING FRONTAL BOUNDARY SAGS SOUTHEASTWARD SATURDAY AFTERNOON,
HIGH PRESSURE QUICKLY FILLS INTO NORTHERN ONTARIO. WEAK LOW
PRESSURE OVER THE NORTHERN PLAINS FORMS INTO SUNDAY AND THIS
WEATHER PATTERN CREATES A SETUP FOR STRONG EASTERLY WINDS ON
LAKE SUPERIOR BLOWING ONSHORE. GUSTS OF 30 TO 40 MPH ARE LIKELY
FOR SOME SHORELINE COMMUNITIES SUNDAY. IF TRENDS CONTINUE IN
THIS GENERAL PATTERN, ALSO EXPECT A NOTABLE LAKE-EHANCED COOL
EASTERLY BREEZE KEEPING TEMPERATURES BELOW-NORMAL IN THE
LOW-70S. THIS PERIOD COULD BE A DAY OF DANGEROUS RIP CURRENTS
CREATING A HIGH SWIM RISK FOR LAKE SUPERIOR BEACHES IN THE TWIN
PORTS. KEEP ON EYE ON THE SURF FORECAST FOR THESE BEACHES IF YOU
HAVE PLANS TO TRY AND GO TO THE BEACH SUNDAY! ALONG WITH THE
HIGH SWIM RISK POTENTIAL IS THE POTENTIAL FOR LOOSE OUTDOOR
FURNITURE TO BE BLOWN AROUND IN THESE KIND OF CONDITIONS. NOW
WOULD BE THE TIME TO CONSIDER ANY PREP THAT MAY BE NEEDED AHEAD
OUTDOOR EVENTS SUNDAY WITH UMBRELLAS, TENTS AND OTHER CHAIRS
AND TABLES. THE TRACK OF THE LOW PRESSURE THROUGH THE NORTHERN
PLAINS WILL BE A LARGE DETERMINING FACTOR ON WHERE THE
STRONGEST JET OF WINDS CAN FORM AND BE AIDED BY ANY FUNNELING
APPROACHING THE SHORELINES.
SEASONABLY SLIGHTLY BELOW NORMAL TEMPERATURES LAST INTO EARLY
NEXT WEEK AS THE HIGH PRESSURE INDUCES PROLONGED LOW-LEVEL
EASTERLY FLOW AND THE NORTHLAND IS RIGHT ON THE GRADIENT OF
COOLER, MORE FALL-LIKE AIRMASS JUST INTO CENTRAL ONTARIO. THIS
SETUP FAVORS THE SOUTHERN THIRD OF THE NORTHLAND FOR OFF-AND-ON
GENERAL THUNDERSTORM CHANCES TOO EARLY NEXT WEEK.
AVIATION /00Z TAFS THROUGH 00Z FRIDAY/
ISSUED AT 640 PM CDT WED AUG 13 2025
DIURNAL CUMULUS WILL DISSIPATE TOWARDS 01Z THIS EVENING. CALM TO
LIGHT WINDS VEER TO SOUTHEASTERLY TONIGHT, WITH SOME FOG
POTENTIAL AT KHIB/KHYR. PROBABILITIES OF IFR VISIBILITY OR
LOWER ARE AROUND 20% AT KHIB AND 20% AT KHYR FOR LIFR VISIBILITY.
AN AREA OF RAIN WITH A FEW EMBEDDED THUNDERSTORMS MOVES INTO
CENTRAL AND NORTH-CENTRAL MINNESOTA STARTING IN ROUGHLY THE
10-13Z TIMEFRAME AND THEN GRADUALLY SHIFTS NORTHEAST THROUGHOUT
DAYTIME THURSDAY. WINDS INCREASE OUT OF THE SOUTHEAST FOR
THURSDAY, WITH GUSTS OF 17-25 KT, STRONGEST IN NORTH-CENTRAL
MINNESOTA.
MARINE /FOR NEAR SHORE WATERS OF WESTERN LAKE SUPERIOR/
ISSUED AT 235 PM CDT WED AUG 13 2025
QUIET WEATHER CONDITIONS PERSIST OVER THE WESTERN WATERS THROUGH
TONIGHT. WINDS SHIFT EASTERLY THURSDAY AND GUST TO 20 KNOTS WITH
WAVE HEIGHTS TO 4 FEET NEAR GRAND MARAIS. EVEN THOUGH WINDS
SHIFT TO SOUTHWESTERLY FRIDAY, A PERIOD OF PROLONGED EASTERLY
WINDS SET UP. THE WEATHER PATTERN ON SUNDAY FAVORS AT LEAST
WIDESPREAD CONDITIONS HAZARDOUS TO SMALL CRAFT. THIS ALSO COULD
(30-40% CHANCE) BE A DAY OF GALE-FORCE WINDS 35-40 KNOTS,
ESPECIALLY INTO THE TWIN PORTS. GALE WATCHES MAY BE NEEDED IN
TIME FOR SUNDAY IF CONFIDENCE CONTINUES TO BUILD IN THIS WEATHER
PATTERN SETTING UP LATE THIS 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...NONE.
DISCUSSION...NLY
AVIATION...ROTHSTEIN
MARINE...NLY
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