053  
FXUS63 KDLH 220928  
AFDDLH  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE DULUTH MN  
428 AM CDT FRI SEP 22 2023  
   
DISCUSSION  
(TODAY THROUGH THURSDAY)  
ISSUED AT 428 AM CDT FRI SEP 22 2023  
 
KEY MESSAGES:  
 
1. AREAS OF FOG LINGER INTO THIS MORNING.  
 
2. A HIGH RISK FOR RIP CURRENTS IS EXPECTED AT BEACHES NEAR THE  
TWIN PORTS FROM THIS AFTERNOON INTO THE WEEKEND DUE TO STRONG  
NORTHEAST WINDS ON WESTERN LAKE SUPERIOR.  
 
3. SCATTERED RAIN SHOWERS AND ISOLATED STORMS TODAY INTO TONIGHT.  
 
4. A FEW STRONG TO MARGINALLY SEVERE STORMS ARE POSSIBLE IN  
CENTRAL MINNESOTA SATURDAY AFTERNOON INTO EARLY EVENING. THE  
PRIMARY THREATS ARE LARGE HAIL AND DAMAGING WIND GUSTS.  
 
5. LOCALLY HEAVY RAIN IS LIKELY WITH SLOW-MOVING STORMS THROUGH  
THIS WEEKEND.  
 
THIS MORNING:  
 
ISOLATED SHOWERS AND STORMS HAVE DEVELOPED EARLY THIS MORNING OVER  
PORTIONS OF WESTERN LAKE SUPERIOR AND THE IRON RANGE/MINNESOTA  
ARROWHEAD. THESE STORMS SHOULD REMAIN GENERALLY WEAK, WITH  
OCCASIONAL LIGHTNING AS A THE MAIN CONCERNS FOR THE NEXT COUPLE  
HOURS AS THEY SLOWLY DRIFT NORTHWARD. IN ADDITION TO THE  
PRECIPITATION, AREAS OF FOG HAVE DEVELOPED THIS MORNING. THIS FOG  
HAS GENERALLY NOT BEEN DENSE EXCEPT FOR ON A VERY PATCHY BASIS. IT  
HAS DEVELOPED PRIMARILY ALONG THE SOUTH SHORE OF LAKE SUPERIOR  
INTO THE INLAND AREAS NEAR THE TWIN PORTS AS WELL AS INLAND  
LOCATIONS ACROSS THE IRON RANGE THAT SAW PRECIPITATION YESTERDAY.  
EXPECT THIS FOG TO BURN OFF WITHIN A COUPLE HOURS AFTER SUNRISE  
THIS MORNING.  
 
TODAY - TONIGHT:  
 
WEAK FORCING FOR ASCENT WILL BE THE STATUS QUO AGAIN TODAY WITH  
REGARDS TO THUNDERSTORM CHANCES. WITH THAT SAID, CAM GUIDANCE DOES  
HIGHLIGHT SCATTERED SHOWERS AND ISOLATED STORMS DEVELOPING FROM  
CENTRAL MINNESOTA INTO NW WISCONSIN THIS AFTERNOON AND GRADUALLY  
MOVING NORTHWARD ACROSS THE NORTHLAND TODAY AND TONIGHT. COVERAGE  
SHOULD BE THE HIGHEST ACROSS NW WISCONSIN INTO THE TWIN PORTS THIS  
EVENING INTO TONIGHT. WITH 0-6 KM BULK SHEAR AROUND 20 KNOTS AND  
MLCAPE VALUES ONLY AROUND 300-600 J/KG, WE EXPECT THESE STORMS TO  
REMAIN BELOW SEVERE LIMITS. CAN'T RULE OUT SOME SMALL HAIL, BRIEF  
GUSTY WINDS, AND LOCALIZED HEAVY DOWNPOURS WITH A FEW OF THE  
THUNDERSTORMS, HOWEVER.  
 
TEMPERATURES WILL REACH INTO THE LOW TO MID 70S TODAY AWAY FROM  
LAKE SUPERIOR AND MID TO UPPER 60S NEAR THE LAKE DUE TO  
INCREASING NORTHEAST WINDS OFF OF THE LAKE TODAY. SUSTAINED WINDS  
OF 10 TO 20 MPH WITH GUSTS UP TO 25 MPH ARE FORECAST IN THE  
SOUTHWEST ARM OF LAKE SUPERIOR, WHICH WILL LEAD TO HIGH RISK FOR  
RIP CURRENTS ALONG THE MINNESOTA PARK POINT AND WISCONSIN POINT  
BEACHES. A BEACH HAZARDS STATEMENT IS IN EFFECT FOR THIS AFTERNOON  
AND EVENING FOR THIS HIGH RISK OF RIP CURRENTS.  
 
THIS WEEKEND:  
 
ENSEMBLE MODEL GUIDANCE IS IN GOOD AGREEMENT ON A VERTICALLY-  
STACKED LOW PRESSURE SYSTEM MOVING ACROSS THE DAKOTAS ON SATURDAY  
AND SETTLING OVER THE WESTERN FRINGE OF THE NORTHLAND ON SUNDAY  
INTO MONDAY. AS A RESULT, THE HIGHEST RAIN CHANCES THIS WEEKEND  
REMAIN FOCUSED ACROSS CENTRAL AND NORTH-CENTRAL MINNESOTA. THE  
MOTIONS OF STORMS WILL GENERALLY BE SLOW, ALONG WITH 1-1.25 INCHES  
OF PWAT (~90TH PERCENTILE RELATIVE TO SOUNDING CLIMATOLOGY) AND  
PLENTY OF SYNOPTIC LIFT FROM THE VERTICALLY-STACKED LOW NEARBY TO  
KICK OFF SCATTERED STORMS WITH LOCALIZED HEAVY RAINFALL POTENTIAL.  
THE LOCALIZED FLASH FLOOD RISK FROM THIS HEAVY RAINFALL WILL BE  
TIED TO WHETHER OR NOT STORMS REPEATEDLY MOVE OVER THE SAME  
LOCATIONS WITH THIS GIVEN ANTECEDENT DROUGHT CONDITIONS ACROSS  
MUCH OF THE NORTHLAND.  
 
IN ADDITION TO THE HEAVY RAIN POTENTIAL, A FEW STRONG TO  
MARGINALLY SEVERE STORMS WILL BE POSSIBLE ON SATURDAY AFTERNOON  
INTO EARLY EVENING OVER THE BRAINERD LAKES VICINITY (SEE THE SPC  
DAY 2 CONVECTIVE OUTLOOK). THERE IS A SMALL WINDOW OF TIME HERE  
WHERE BULK SHEAR VECTORS AROUND 30-40 KNOTS, MLCAPE AROUND 1000  
J/KG, AND MID-LEVEL LAPSE RATES AROUND 7.5 DEGREES C/KM COULD  
ORGANIZED STORMS ENOUGH TO PRODUCE HAIL UP TO THE SIZE OF QUARTERS  
AND WIND GUSTS UP TO 60 MPH. INSTABILITY, AND THUNDERSTORM  
STRENGTH, SHOULD WEAKEN DURING THE EARLY EVENING WITH THE LOSS OF  
DAYTIME HEATING.  
 
OUTSIDE OF PRECIPITATION CHANCES THIS WEEKEND, OTHER IMPACTFUL  
WEATHER THIS WEEKEND WILL BE BE STRONG AND GUSTY EAST TO SOUTHEAST  
WINDS. SUSTAINED WINDS AROUND 15 TO 25 MPH WITH GUSTS UP TO AROUND  
35 MPH ARE FORECAST, BEING THE STRONGEST SATURDAY EVENING INTO  
SUNDAY. THESE WINDS WILL LIKELY LEAD TO ADDITIONAL HIGH RISK OF  
RIP CURRENTS ALONG THE MINNESOTA PARK POINT AND WISCONSIN POINT  
BEACHES.  
 
NEXT WEEK:  
 
AS THE LOW PRESSURE BREAKS DOWN ON MONDAY AND DIVES SOUTHEAST, A  
SHORTWAVE RIDGE WILL MOVE BACK OVER THE UPPER-MIDWEST FOR MUCH OF  
NEXT WEEK. THIS SHOULD LEAD TO GENERALLY MORE QUIET WEATHER WITH A  
SLIGHT WARMING TREND BACK IN THE UPPER 60S TO 70S (A FEW DEGREES  
ABOVE NORMAL FOR THIS TIME OF YEAR) AND MAINLY DRY WEATHER UNTIL  
LATER IN THE WEEK.  
 
 
   
AVIATION  
(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT)  
ISSUED AT 1236 AM CDT FRI SEP 22 2023  
 
MOST SHOWERS AND STORMS HAVE MOVED NORTH OF THE CANADIAN BORDER,  
ALTHOUGH THERE ARE A COUPLE STRAY SHOWERS IN SOUTHERN ASHLAND AND  
BAYFIELD COUNTIES THAT WILL SLOWLY MEANDER NORTHWEST OVER THE NEXT  
COUPLE HOURS. NORTHEAST WINDS OFF THE LAKE HAVE BEGUN TO DEVELOP  
DURING THE CURRENT OVERNIGHT HOURS. THIS WILL LEAD TO LOW CLOUDS  
AND FOG DEVELOPING AT DLH. HIB HAS ALSO SEEN A DROP IN  
VISIBILITIES AND LOW CEILINGS IN FOG THAT WILL CONTINUE OVERNIGHT  
DUE TO LINGERING LOW LEVEL MOISTURE FROM STORMS THAT PASSED  
OVERHEAD TODAY. ALSO CANNOT RULE OUT PATCHY FOG AT HYR AND INL  
TONIGHT, THOUGH DENSER FOG IS NOT EXPECTED AT THOSE LOCATIONS.  
IFR TO LIFR CEILINGS/VISIBILITIES ARE EXPECTED TO LINGER INTO INTO  
A COUPLE HOURS AFTER SUNRISE BEFORE VFR CONDITIONS RETURN BY LATE  
THIS MORNING. THERE ARE CHANCES FOR ISOLATED SHOWERS NEAR INL  
TODAY AS WELL AS AT THE REMAINING TAF SITES THIS AFTERNOON, WITH  
THE HIGHEST POTENTIAL AT HYR.  
 
 
   
MARINE  
 
ISSUED AT 428 AM CDT FRI SEP 22 2023  
 
LIGHTER NORTHEAST WINDS THIS MORNING WILL INCREASE BY THIS  
AFTERNOON AND EVENING WITH GUSTS TO AROUND 20 TO 25 KNOTS. THESE  
WINDS BECOME EVEN STRONGER ON SATURDAY INTO SUNDAY AS HIGH  
PRESSURE MOVES INTO FAR NORTHEAST ONTARIO AND A CLOSED LOW  
PRESSURE APPROACHES FROM THE SOUTHWEST, LEADING TO A TIGHT  
PRESSURE GRADIENT. AS A RESULT, WIDESPREAD NORTHEAST WINDS OF 15  
TO 25 KNOTS WITH GUSTS UP TO AROUND 30 KNOTS ARE EXPECTED, WITH  
THE HIGHEST OF THESE GUSTS ALONG THE NORTH SHORE FROM TWO HARBORS  
TO TOFTE. SOME GUSTS MAY APPROACHING GALE FORCE ARE POSSIBLE OVER  
THOSE WATERS BOTH SATURDAY AND SUNDAY AFERNOONS AND EVENINGS,  
THOUGH THE WIND FORECAST HAS TRENDED SLIGHTLY WEAKER BY A COUPLE  
KNOTS RELATIVE TO THE PREVIOUS FORECAST. THE HIGHEST WAVES WILL  
BEGIN AT THE HEAD OF THE LAKE WITH 3 TO 5 FEET THIS AFTERNOON AND  
EVENING. INCREASING NORTHEAST WINDS SATURDAY SHOULD INCREASE WAVE  
HEIGHTS TO 4 TO 8 FEET FOR MUCH OF WESTERN LAKE SUPERIOR, HIGHEST  
IN THE SOUTHWESTERN ARM OF LAKE SUPERIOR. SMALL CRAFT ADVISORIES  
ARE IN EFFECT STARTING THIS AFTERNOON IN THE TWIN PORTS NEARSHORE  
ZONES, AND EXPAND TO INCLUDE MUCH OF WESTERN LAKE SUPERIOR TONIGHT  
INTO SUNDAY NIGHT. CONFIDENCE IN APPROACHING GALE FORCE WINDS WAS  
TOO LOW WITH THE CURRENT FORECAST UPDATE, SO WE DECIDED NOT TO  
ISSUE ANY GALE WATCHES WITH THIS UPDATE.  
 
 
   
PRELIMINARY POINT TEMPS/POPS  
 
DLH 70 56 67 55 / 20 40 50 30  
INL 72 55 70 55 / 30 10 30 40  
BRD 75 58 73 57 / 30 40 80 80  
HYR 77 57 74 55 / 30 50 40 INTO20  
ASX 73 56 72 56 / 20 40 40 20  
 
 
   
DLH WATCHES/WARNINGS/ADVISORIES  
 
WI...BEACH HAZARDS STATEMENT FROM 2 PM CDT THIS AFTERNOON THROUGH  
THIS EVENING FOR WIZ001.  
 
MN...BEACH HAZARDS STATEMENT FROM 2 PM CDT THIS AFTERNOON THROUGH  
THIS EVENING FOR MNZ037.  
 
LS...SMALL CRAFT ADVISORY FROM 10 AM SATURDAY TO 1 AM CDT MONDAY FOR  
LSZ140.  
 
SMALL CRAFT ADVISORY FROM 1 AM SATURDAY TO 4 AM CDT MONDAY FOR  
LSZ141>143.  
 
SMALL CRAFT ADVISORY FROM 3 PM THIS AFTERNOON TO 4 AM CDT MONDAY  
FOR LSZ144-145.  
 
SMALL CRAFT ADVISORY FROM 10 PM THIS EVENING TO 1 AM CDT MONDAY  
FOR LSZ146-147-150.  
 
 
 
 
 
DISCUSSION...ROTHSTEIN  
AVIATION...ROTHSTEIN  
MARINE...ROTHSTEIN  
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