390
FXUS63 KDLH 040913
AFDDLH
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DULUTH MN
413 AM CDT THU SEP 4 2025
KEY MESSAGES
- AREAS OF FROST EARLY THIS MORNING.
- ISOLATED LIGHT RAIN CHANCES THROUGH EARLY MORNING, POSSIBLY
MIXED WITH A FEW SNOW FLAKES IN THE TIP OF THE ARROWHEAD.
- WIDESPREAD RAIN PRIMARILY ALONG AND SOUTH OF US-2 THIS
AFTERNOON THROUGH TONIGHT, WITH LINGERING SCATTERED SHOWERS
FOR PORTIONS OF THE NORTHLAND ON FRIDAY.
- COOL TEMPERATURES LINGER INTO THE END OF THE WEEK, THEN A
GRADUAL WARM UP INTO NEXT WEEK. SOME FROST POTENTIAL CONTINUES
EACH NIGHT FOR TONIGHT INTO THE WEEKEND.
DISCUSSION
ISSUED AT 412 AM CDT THU SEP 4 2025
THIS MORNING:
WEAK SYNOPTIC FORCING AND CYCLONIC FLOW ALOFT HAS KEPT A FEW
LIGHT SHOWERS HANGING AROUND THE NORTHLAND THAT SHOULD FADE
TOWARDS THE DAYLIGHT HOURS. THE MAIN IMPACT FROM THIS CYCLONIC
FLOW HAS BEEN SCATTERED CLOUD COVER OVER THE REGION. THIS CLOUD
COVER HAD BEEN HANGING AROUND OVER NORTH-CENTRAL AND NORTHEAST
MN DURING THE EVENING INTO THE CURRENT OVERNIGHT, BUT HAS SINCE
EXPANDED INTO PORTIONS OF NORTHWEST WI. AREAS THAT HAVE SEEN AT
LEAST A FEW HOURS OF CLEARING OVERNIGHT--NAMELY FAR NORTHERN
MN, THE NORTH SHORE, AND INLAND NORTHWEST WI--HAVE SEEN
TEMPERATURES DROP INTO THE MID TO UPPER 30S WITH LIGHT WINDS.
GIVEN WE STILL HAVE SEVERAL HOURS UNTIL SUNRISE, AREAS THAT
CONTINUE TO SEE CLEARING WILL HAVE A CONTINUED THREAT FOR FROST, ASIDE
FROM THE BRAINERD LAKES INTO EAST-CENTRAL MN WHERE LONGER
PERIODS OF CLOUD COVER HAVE KEPT TEMPERATURES SO FAR IN THE LOW
TO MID 40S. AREAS IMMEDIATELY NEAR LAKE- SUPERIOR SHOULD ALSO BE
PROTECTED FROM FROST EARLY THIS MORNING, PARTICULARLY ALONG THE
SOUTH SHORE. I HAVE NOT MADE SIGNIFICANT ADJUSTMENTS TO THE
FROST ADVISORIES GIVEN THE FROST SHOULD NOT BE WIDESPREAD.
THIS AFTERNOON - TONIGHT:
THE UPPER-LEVEL LOW LEADING TO CYCLONIC FLOW ACROSS THE
NORTHLAND EARLY TODAY WILL CONTINUE TO RETROGRADE ACROSS
NORTHERN ONTARIO. A CLIPPER QUICKLY DIVING SOUTHEAST OUT OF
ALBERTA THROUGHOUT TODAY AND INTO THE NORTHLAND THIS AFTERNOON
AND TONIGHT WILL BRING A WIDESPREAD LIGHT TO MODERATE RAIN
PRIMARILY TO AREAS ALONG AND SOUTH OF US-2 WITH IT. FORECAST
RAINFALL AMOUNTS HAVE INCREASED WITH THIS FORECAST UPDATE, WITH
ACCUMULATIONS OF 0.5-1" POSSIBLE IN INLAND NORTHWEST WI,
0.25-0.5" ALONG AND SOUTH OF US-2, WITH AMOUNTS QUICKLY DROPPING
OFF NORTH OF US-2 IN NORTH-CENTRAL AND NORTHEAST MN. CAN'T RULE
OUT AN EMBEDDED RUMBLE OF THUNDER OR TWO (LESS THAN 20% CHANCE) IN
CENTRAL MN TO INLAND NORTHWEST WI THIS EVENING, BUT INSTABILITY
IS VERY MEAGER.
TEMPERATURES REMAIN COOL TODAY, WITH HIGHS IN THE 50S TO AROUND
60F AND LOWS TONIGHT GENERALLY IN THE UPPER 30S TO LOW 40S. MORE
CLOUD COVER ASSOCIATED WITH THE RAIN SHOULD DRASTICALLY LIMIT
FROST POTENTIAL FOR TONIGHT. A FEW POCKETS OF MID 30S IN THE TIP
OF THE ARROWHEAD ARE POSSIBLE WHERE RAIN CHANCES ARE LOWEST,
BUT THE CLOUD COVER AND INCREASING WINDS TONIGHT SHOULD LARGELY
MITIGATE THE FROST RISK THERE, AS WELL.
FRIDAY - SATURDAY NIGHT:
RAIN ASSOCIATED WITH THE CLIPPER MOVES EAST OF THE AREA BY
FRIDAY MORNING, BUT LINGERING MOISTURE ASSOCIATED WITH COLDER CYCLONIC
FLOW ON THE BACK SIDE OF THE ONTARIO UPPER-LEVEL LOW SHOULD KEEP
SCATTERED SHOWER ACTIVITY PERSISTING FOR MUCH OF FRIDAY WITH AN
ADDITIONAL SHORTWAVE ON SATURDAY ALSO POTENTIALLY LEADING TO
ISOLATED SHOWERS (10-30% CHANCE), MAINLY DURING THE AFTERNOON.
NEITHER OF THESE ROUNDS OF RAIN SHOULD AMOUNT TO MUCH IN THE WAY
OF ADDITIONAL RAIN ACCUMULATIONS, BUT THE COLDER AIR SHOULD RAMP
UP SOME LAKE-EFFECT RAIN SHOWERS FOR PORTIONS OF THE SOUTH SHORE
FOR FRIDAY AND SATURDAY, AS WELL.
COOLER TEMPERATURES PERSIST ON FRIDAY AND SATURDAY, WITH HIGHS
LARGELY IN THE 50S, WHILE OVERNIGHT LOWS DIP INTO THE MID 30S TO
LOW 40S. MANY OF THE HIGH TEMPERATURES ON FRIDAY COULD FLIRT
WITH RECORD LOW MAXIMUM HIGH TEMPERATURES (SEE THE "CLIMATE
SECTION" BELOW FOR DETAILS). GUSTY WINDS ARE IN STORE FOR
FRIDAY, WITH GUSTS UP TO 20-30 MPH GIVEN A TIGHT PRESSURE
GRADIENT BEFORE WINDS WEAKEN FRIDAY NIGHT. ADDITIONAL FROST
POTENTIAL CONTINUES FOR FRIDAY AND SATURDAY NIGHTS, BUT
UNCERTAINTY REGARDING THE AMOUNT OF LINGERING CLOUD COVER--
PARTICULARLY ON SATURDAY NIGHT WHEN LOWS SHOULD BE A FEW DEGREES
COOLER--COULD AFFECT HOW WIDESPREAD THE FROST WILL BE.
SUNDAY - NEXT WEEK:
GLOBAL ENSEMBLES AND CLUSTERS POINT TO MID- AND UPPER-LEVEL
RIDGING MOVING BACK INTO THE CENTRAL CONUS NEXT WEEK, USHERING A
WARMING TREND BACK INTO THE NORTHLAND STARTING ON SUNDAY. HIGHS
ON SUNDAY ARE FORECAST TO BE IN THE UPPER 50S TO MID 60S, WITH
MID 60S TO MID 70S ACROSS THE AREA NEXT WEEK WHICH ARE CLOSER TO
NORMAL TEMPERATURES FOR EARLY SEPTEMBER. LOWS NEXT WEEK SHOULD
ALSO BE IN THE MID 40S TO 50S, WHICH SHOULD STAVE OFF ANY
ADDITIONAL FROST CONCERNS FOR A WHILE AFTER THIS WEEKEND.
RETURN MOISTURE GIVEN SOUTHERLY TO SOUTHWESTERLY SURFACE WINDS
AND A SHORTWAVE TROUGH MOVING THROUGH THE NORTHEAST FLOW ALOFT
ON THE EASTERN SIDE OF THE MID- AND UPPER-LEVEL RIDGES WOULD
BRING THE NEXT POTENTIAL FOR SHOWERS AND THUNDERSTORMS MONDAY
NIGHT INTO TUESDAY, THOUGH DETAILS ON PRECIPITATION AMOUNTS AND
PLACEMENT REMAIN A BIT FUZZY AT THIS TIME.
AVIATION /06Z TAFS THROUGH 06Z FRIDAY/
ISSUED AT 1247 AM CDT THU SEP 4 2025
VERY ISOLATED, INTERMITTENT RAIN SHOWERS PERSIST DURING THE
CURRENT OVERNIGHT, BUT DECREASE IN COVERAGE TOWARDS THIS
MORNING. WINDS REMAIN WEST-NORTHWESTERLY TO WESTERLY INTO MOST
OF THURSDAY, WITH WINDS PICKING UP MID TO LATE MORNING INTO
AFTERNOON WITH GUSTS OF 14-18 KT FOR MOST AREAS. BETTER
POTENTIAL FOR MORE WIDESPREAD RAIN SHOWERS RETURN TO THE AREA
FROM THE WEST BY MID TO LATE AFTERNOON AND PERSIST THROUGH AT
LEAST THE END OF THE CURRENT TAF PERIOD, THOUGH INL MAY BE MORE
ON THE FRINGE FOR SHOWERS. CONDITIONS SHOULD DETERIORATE WITH
THE SHOWERS, AS WELL, WITH MVFR CONDITIONS FOR KHIB/KDLH AND
TERMINALS SOUTH IN THE EVENING AND POTENTIALLY IFR CEILINGS AT
KBRD/KHYR AFTER 03Z ON THURSDAY EVENING.
MARINE /FOR NEAR SHORE WATERS OF WESTERN LAKE SUPERIOR/
ISSUED AT 412 AM CDT THU SEP 4 2025
NORTHWEST WINDS EARLY THIS MORNING TURN WESTERLY WITH GUSTS
HOVERING TO AROUND 15-25 KT FOR MANY PORTIONS OF THE NEARSHORE
WATERS CONTINUE TODAY INTO EARLY THIS EVENING, WITH WAVES OF 2-5
FEET FOR PORT WING AND AREAS EAST ALONG THE SOUTH SHORE. THESE
WINDS AND WAVES BRIEFLY WEAKEN THIS EVENING BEFORE WINDS
INCREASE AGAIN OUT OF THE NORTHWEST LATER TONIGHT THROUGH
FRIDAY AS A CLIPPER SYSTEM MOVES THROUGH, WITH GUSTS OF 20-30
KT THAT WILL BE HAZARDOUS FOR SMALLER VESSELS THROUGH AT LEAST
FRIDAY EVENING. WINDS THEN GRADUALLY DECREASE INTO SATURDAY.
WHILE NOT COMPLETELY ZERO, THERE IS A SMALL CHANCE (10%) FOR
WATERSPOUTS NEAR/ALONG THE SOUTH SHORE TONIGHT INTO FRIDAY
MORNING.
FOR THE OPEN WATER DISCUSSION, REFER TO THE NWS MARQUETTE AREA
FORECAST DISCUSSION AT WEATHER.GOV/MQT.
CLIMATE
ISSUED AT 312 AM CDT THU SEP 4 2025
RECORD LOW MAXIMUM TEMPERATURES FOR SITES THAT HAVE A FORECAST
WITHIN 3 DEGREES F OF THE RECORD LOW MAXIMUM TEMPERATURES LISTED
BELOW:
SEPTEMBER 4:
KHIB: 54/1962
SEPTEMBER 5:
KDLH: 52/1904
KINL: 53/1965
KBRD: 57/1962
KHIB: 54/2017
KASX: 56/1926
DLH WATCHES/WARNINGS/ADVISORIES
MN...FROST ADVISORY UNTIL 8 AM CDT THIS MORNING FOR MNZ010>012-
018>021-025-026-035-037.
WI...FROST ADVISORY UNTIL 8 AM CDT THIS MORNING FOR WIZ001>004-
006>009.
MARINE...SMALL CRAFT ADVISORY UNTIL 8 PM CDT THIS EVENING FOR LSZ121-
140>143-146>148-150.
SMALL CRAFT ADVISORY UNTIL 5 PM CDT THIS AFTERNOON FOR LSZ144-
145.
DISCUSSION...ROTHSTEIN
AVIATION...ROTHSTEIN
MARINE...ROTHSTEIN
CLIMATE...ROTHSTEIN
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