539
FXUS63 KDLH 180607
AFDDLH
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DULUTH MN
107 AM CDT MON AUG 18 2025
KEY MESSAGES
- ANOTHER ROUND OF RAIN AND THUNDERSTORMS BEGINS THIS AFTERNOON
AND CONTINUES OVERNIGHT INTO MONDAY MORNING.
- HIGH PRESSURE AND DRIER CONDITIONS BUILD INTO THE AREA FOR
TUESDAY INTO THURSDAY MORNING WITH NEAR NORMAL TEMPERATURES.
- THE NEXT CHANCE FOR PRECIPITATION IS LATE IN THE WORK WEEK.
DISCUSSION
ISSUED AT 258 PM CDT SUN AUG 17 2025
TODAY HAS BEEN ALMOST FALL LIKE, WITH STRONG EASTERLY WINDS,
STRATUS CLOUDS STREAMING OFF LAKE SUPERIOR, AND COOL
TEMPERATURES. A LOW PRESSURE SYSTEM DEVELOPING OVER SOUTH DAKOTA
WITH A WARM FRONT EXTENDING EAST OVER CENTRAL MINNESOTA AND
INTO WISCONSIN. THIS SYSTEM WILL PUSH EAST-NORTHEAST TODAY
THROUGH TOMORROW, WITH THE LOW CENTER AND WARM FRONT STAYING
JUST SOUTH OF THE FORECAST AREA. THIS WILL CAUSE A SURGE OF
WARM, MOIST AIR UP OVER THE FRONT, AND IS CURRENTLY PRODUCING A
LARGE AREA OF SHOWERS AND THUNDERSTORMS OVER EASTERN NORTH AND
SOUTH DAKOTA AND WESTERN MINNESOTA. THESE WILL PUSH INTO THE
FORECAST AREA THIS AFTERNOON AND TONIGHT IN WAVES OF SHOWERS AND
EMBEDDED THUNDERSTORMS TONIGHT AND MONDAY MORNING BEFORE
EXITING OFF TO THE EAST MONDAY AFTERNOON AND EVENING. THE
PROBABILITY OF GETTING MORE THAN A HALF INCH OF RAINFALL BY
MONDAY EVENING IS OVER 50 PERCENT FOR NORTHERN MINNESOTA AND
MOST OF NORTHWEST WISCONSIN. THE MOST RAIN SHOULD FALL IN A
CORRIDOR FROM THE BRAINERD AND MILLE LACS LAKES AREA EAST
THROUGH THE TWIN PORTS AND BAYFIELD PENINSULA, WHERE RAINFALL
AMOUNTS OF OVER AN INCH AND A HALF ARE POSSIBLE.
A RIDGE OF HIGH PRESSURE NOSES INTO THE AREA MONDAY NIGHT INTO
TUESDAY AND LINGERS OVER THE AREA THROUGH WEDNESDAY NIGHT,
GIVING US A PERIOD OF QUIETER AND DRIER WEATHER WITH NEAR NORMAL
TEMPERATURES.
ACTIVE WEATHER WITH SEVERAL PRECIPITATION CHANCES RETURNS
THURSDAY INTO FRIDAY WITH A STRONG UPPER LOW THAT MOVES ACROSS
THE CANADIAN PRAIRIES, ACROSS ONTARIO AND INTO QUEBEC THURSDAY
THROUGH SATURDAY. CONFIDENCE IS INCREASING IN THIS GENERAL
SCENARIO, BUT THE DETAILS OF THE STRENGTH OF THE SYSTEM AS WELL
AS TIMING HAVE YET TO BE NARROWED DOWN. FOR NOW, PRECIPITATION
CHANCES HAVE INCREASED FOR THURSDAY NIGHT INTO FRIDAY. WE SHOULD
HAVE SOME WARMER THAN NORMAL TEMPERATURES THURSDAY AND FRIDAY,
SHIFTING TO COOLER THAN NORMAL FOR NEXT WEEKEND.
AVIATION /06Z TAFS THROUGH 06Z TUESDAY/
ISSUED AT 1238 AM CDT MON AUG 18 2025
EAST TO SOUTHEAST BREEZY WINDS CONTINUE TONIGHT, WITH GUSTS UP
TO 25KTS. OROGRAPHICALLY ENHANCED CLOUDS CONTINUE AT DLH, WITH A
MIX OF MVFR/IFR HEIGHTS. AN APPROACHING TROUGH WILL BRING
SHOWERS AND THUNDERSTORMS TO TERMINALS OVERNIGHT THROUGH MONDAY
MORNING. CURRENTLY A BROKEN BAND OF SHOWERS IS MOVING EASTWARD
THROUGH INL TO HIB TO DLH TO HYR. BEHIND THE LINE, IT IS
POSSIBLE ADDITIONAL SHOWERS AND A COUPLE THUNDERSTORMS DEVELOP
OVERNIGHT AND ALSO MOVE WEST TO EAST THROUGH THE AREA. GIVEN THE
SCATTERED NATURE OF EXPECTED COVERAGE, HAVE INCLUDE VCSH/VCTS
WITH PREVAILING SHRA AT TIMES. WITH INCREASING LOW LEVEL
MOISTURE, CIGS WILL FALL TO IFR FOR ALL TERMINALS EXCEPT HYR,
WHICH WILL REMAIN WITHIN THE MVFR CATEGORY. THESE LOW CIGS WILL
PERSIST THROUGH MONDAY. WIND SPEEDS DECREASE THROUGH AFTERNOON
MONDAY, BECOMING LESS THAN 5KTS MONDAY EVENING.
MARINE /FOR NEAR SHORE WATERS OF WESTERN LAKE SUPERIOR/
ISSUED AT 318 PM CDT SUN AUG 17 2025
NORTHEAST WINDS CONTINUING TO BLOW HARD, WITH GUSTS OF UP TO 36
KNOTS SO FAR. WIND GUSTS SHOULD BE STRONGEST NOW THROUGH 8PM.
THIS IS BEING CAUSED BY A TIGHTENING PRESSURE GRADIENT OVER
WESTERN LAKE SUPERIOR BETWEEN HIGH PRESSURE OVER ONTARIO AND
INCOMING LOW PRESSURE PASSING THROUGH SOUTH DAKOTA AND SOUTHERN
MINNESOTA LATER TODAY. SUSTAINED WIND SPEEDS AROUND 20 KNOTS
WITH GALE FORCE GUSTS, MAINLY FOR THE SOUTHWEST TIP OF THE LAKE.
THESE WINDS WILL BUILD LARGE WAVE HEIGHTS, WHICH IS UNUSUAL FOR
THIS TIME OF YEAR, ACROSS ALL WATERS RANGING FROM 3 TO 6 FEET.
EXPECT DANGEROUS CONDITIONS FOR SMALL CRAFT AND VESSELS THROUGH
THIS EVENING WITH ADVISORIES IN EFFECT. THE GALE WARNING
CONTINUES THROUGH 10 PM THIS EVENING. A SMALL CRAFT ADVISORY
WILL BE NEEDED AFTER 10 PM. THE SMALL CRAFT ADVISORIES HAVE BEEN
EXTENDED TONIGHT INTO MONDAY MORNING, THOUGH AN EXTENSION MAY BE
NEEDED LONGER ON MONDAY AS ELEVATED SWELL LINGERS. THE NEXT
ROUND OF THUNDERSTORMS BUILDS WEST TO EAST THIS EVENING AND
GENERAL THUNDERSTORM HAZARDS ARE LIKELY TONIGHT INTO MONDAY MID-
DAY.
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 4 AM CDT EARLY THIS MORNING FOR
LSZ121-144>148-150.
SMALL CRAFT ADVISORY UNTIL 10 AM CDT THIS MORNING FOR
LSZ140>143.
DISCUSSION...LE
AVIATION...HA
MARINE...LE
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