318  
FXUS63 KDLH 191131  
AFDDLH  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE DULUTH MN  
531 AM CST SUN JAN 19 2025  
   
KEY MESSAGES  
 
- ARCTIC COLD AND DANGEROUS WIND CHILLS ARE FORECAST THROUGH  
TUESDAY MORNING AND AN EXTREME COLD WARNING IS IN EFFECT.  
 
- PROLONGED LIGHT LAKE-EFFECT SNOW IS EXPECTED THROUGH  
TUESDAY. HIGHEST ACCUMULATIONS OF 3-7 INCHES WILL BE IN THE  
BAYFIELD PENINSULA WITH LOWER TOTALS OF UP TO 4 INCHES IN  
NORTHERN IRON COUNTY.  
 
 
   
DISCUSSION  
 
ISSUED AT 335 AM CST SUN JAN 19 2025  
 
NOT MUCH TO SAY THIS MORNING AS WE TRY TO CONSERVE WARMTH. IT'S  
COLD AND WILL REMAIN COLD FOR THE NEXT SEVERAL DAYS. AS OF 3 AM  
TEMPERATURES AROUND THE NORTHLAND WERE GENERALLY IN THE LOW  
SINGLE DIGITS TO 20S BELOW ZERO. WIND CHILLS SO FAR TONIGHT  
RANGED FROM AROUND 20 TO 50 BELOW ZERO. EXPECT THE DANGEROUS  
WIND CHILLS TO PERSIST THROUGH THE NEXT FEW DAYS. AS  
TEMPERATURES WARM DIURNALLY, THERE WILL BE SEVERAL HOURS EACH  
DAY WHEN THERE WILL BE IMPROVEMENT IN THE WIND CHILLS. NO  
CHANGES TO THE EXTREME COLD WARNING WERE MADE SINCE THE OVERALL  
MESSAGE REMAINS THE SAME. HIGHS TODAY WILL REACH THE SINGLE  
DIGITS TO UPPER TEENS BELOW ZERO, EXCEPT NEAR THE LAKE SUPERIOR  
SHORE IN NORTHWEST WISCONSIN WHERE TEMPERATURES MAY CLIMB ABOVE  
ZERO DUE TO ONSHORE FLOW FROM THE COMPARATIVELY WARM WATERS.  
 
LAKE-EFFECT SNOW WILL CONTINUE OVER NORTHEAST DOUGLAS, NORTHERN  
BAYFIELD, EXTREME NORTHEAST ASHLAND, AND NORTHERN IRON COUNTIES  
IN NORTHWEST WISCONSIN TODAY. EARLY MORNING GOES-EAST CHANNEL  
13 (CLEAN WINDOW IR) IMAGERY REVEALS THIN AND SHALLOW CONVECTIVE  
PLUMES EMANATING FROM ALL OF THE INLAND LAKES DESPITE THEIR ICE  
COVER. THEY REMAIN MUCH WARMER THAN THE ARCTIC AIRMASS IN  
PLACE. IT'S LIKELY THESE CLOUDS ARE VERY THIN AND TRANSPARENT TO  
TRANSLUCENT. ONCE THE SUN IS OVER THE HORIZON, VISIBLE CHANNEL  
2 IMAGERY CAN REVEAL THEIR DEPTH. WE EXPECT TO SEE LIGHT  
FLURRIES FALLING ACROSS THE NORTHLAND WHEREVER THE THIN, LOW  
STRATUS REMAINS OVER THE NEXT 36 HOURS.  
 
WE RECEIVED A REPORT FROM GILE AROUND 1230 AM WITH 1.1 INCHES  
OF SNOW SO FAR. IT'S LIKELY AREAS IN THE NORTHWEST WISCONSIN  
SNOWBELT WILL SEE 1-2 INCHES OF FLUFFY ACCUMULATION EVERY 12  
HOURS UNTIL THE WIND DIRECTION AND TEMPERATURES ALOFT CHANGE. BY  
NOON TUESDAY, SOME LOCATIONS MAY PICK UP 3 TO 7 INCHES WITH A  
FEW SPOTS PERHAPS SEEING AS MUCH AS 8 INCHES. THE LONG-DURATION,  
SLOW ACCUMULATION RATE, AND LIMITED AREA OF ACCUMULATION SEEM  
TO PRECLUDE SNOW HEADLINES AT THIS TIME. ONCE COCORAHS, COOP,  
AND SPOTTER REPORTS START COMING IN THIS MORNING, WE MAY NEED TO  
REASSESS THAT COURSE OF ACTION IF SNOW ACCUMULATION IS GREATER  
THAN WE EXPECT. WITH VERY DRY AIR UPSTREAM OF LAKE SUPERIOR, ALL  
OF THE PRECIPITATION IS THE RESULT OF SENSIBLE HEAT AND  
MOISTURE FLUX FROM THE SHORT FETCH OVER THE SOUTHWEST ARM OF THE  
LAKE. TEMPERATURES ARE COLD ENOUGH TO REVEAL A SNOW BAND  
DOWNWIND FROM MADELINE ISLAND AFFECTING NORTHERN IRON COUNTY.  
EVEN ACROSS THAT SHORT FETCH, THERE IS SUFFICIENT HEAT AND  
MOISTURE TRANSFER FOR ACCUMULATING SNOW.  
 
ANOTHER COLD NIGHT ON TAP TONIGHT WITH LOWS FROM AROUND 19 TO  
26 BELOW ZERO. MINIMUM WIND CHILLS WILL BE IN THE -35 TO -50  
DEGREE RANGE. TEMPERATURES STAY BELOW ZERO ON MONDAY, PERHAPS  
EVEN COLDER THAN TODAY'S HIGHS AS ANOTHER SURGE OF ARCTIC AIR  
ALOFT ARRIVES. LOOK FOR HIGHS GENERALLY FROM -5 TO -15 DEGREES.  
LOWS MONDAY NIGHT AND TUESDAY MORNING WILL DIP INTO THE -20 TO  
-30 DEGREE RANGE, WITH SOME TYPICALLY COLDER SPOTS POSSIBLE  
AS COLD AS -40. WIND CHILLS WILL BOTTOM OUT IN THE -35 TO -50  
RANGE AGAIN.  
 
A PATTERN CHANGE IS EXPECTED AROUND MIDWEEK AS A POSITIVELY  
TILTED RIDGE PROPAGATES SOUTHEASTWARD ACROSS THE REGION TUESDAY  
FOLLOWED BY A SHORTWAVE TROUGH ON WEDNESDAY. THE RIDGE WILL BACK  
WINDS WESTERLY AND SOUTHWESTERLY PUSHING THE ARCTIC AIR OUT OF  
THE REGION TO THE EAST. THE SHORTWAVE TROUGH WILL BRING A CHANCE  
OF LIGHT SNOW. WHILE THE DETERMINISTIC AND ENSEMBLE GUIDANCE  
ALL HAVE SOME AMOUNT OF PRECIPITATION OVER THE NORTHLAND  
WEDNESDAY AND THURSDAY, THE GUIDANCE HAS BEEN OVERLY OPTIMISTIC  
WITH SNOW CHANCES FOR THE PAST MONTH OR SO. THERE JUST ISN'T  
ENOUGH MOISTURE ADVECTION AHEAD OF THE TROUGHS TO GENERATE MORE  
THAN A BRIEF PERIOD OF LIGHT SNOW. THINK THAT'S THE MOST LIKELY  
OUTCOME WITH THE MIDWEEK SHORTWAVE.  
 
TEMPERATURES WILL LIKELY CLIMB ABOVE ZERO EITHER TUESDAY NIGHT  
OR WEDNESDAY WITH HIGHS IN THE TEENS AND LOW 20S THROUGH NEXT  
WEEKEND.  
 
 
   
AVIATION /12Z TAFS THROUGH 12Z MONDAY/  
 
ISSUED AT 532 AM CST SUN JAN 19 2025  
 
VERY COLD CONDITIONS EXPECTED TODAY. GOES-EAST CHANNEL 13  
(CLEAN WINDOW IR) IMAGERY REVEALS CLOUDS STREAMING FROM INLAND  
LAKES OVER NORTHEAST MINNESOTA AND UPSTREAM INTO MANITOBA AND  
NORTHWEST ONTARIO (DESPITE THEIR ICE COVER). THESE ARE LIKELY  
THIN, ALMOST TRANSPARENT ICE CLOUDS GIVEN THE TEMPERATURES  
ACROSS THE REGION. LAMP AND NAM GUIDANCE CONTINUES TO SUGGEST A  
PERIOD OF IFR OR MVFR CEILINGS LATE THIS MORNING INTO THE  
AFTERNOON. WITH THE COLD AIR IN PLACE AND SLIGHT MOISTURE  
INFUSION FROM THE INLAND LAKES, DIURNAL HEATING MAY BE ENOUGH TO  
GENERATE SHALLOW CONVECTION AND LOW CEILINGS WITH SNOW SHOWERS.  
CONFIDENCE IN THIS SCENARIO IS NOT HIGH. SURFACE OBS FROM 11Z  
OVER SOUTHERN MANITOBA AND NORTHWEST ONTARIO SHOW CEILINGS  
AROUND 5KFT AGL. THUS HAVE ADDED ANOTHER CLOUD LAYER AT THAT  
HEIGHT AT THE TERMINALS LATER TODAY. AT HIB A COMBINATION OF  
ANTHROPOGENIC AND INLAND LAKE-EFFECT PROCESSES CONTINUE TO  
PRODUCE LOW CEILINGS AND VISIBILITY. WE EXPECT THE VISIBILITY  
REDUCTIONS ARE DUE TO LIGHT SNOW AND ICE CRYSTALS. AS  
TEMPERATURES WARM LATER THIS MORNING, THE CEILINGS SHOULD LIFT  
AND MAY ALLOW THE SNOW AND ICE CRYSTALS TO SUBLIMATE YIELDING  
VFR VISIBILITY.  
 
 
   
MARINE /FOR NEAR SHORE WATERS OF WESTERN LAKE SUPERIOR/  
 
ISSUED AT 335 AM CST SUN JAN 19 2025  
 
COLD AND CONDITIONS WITH GUSTY NORTHWEST WINDS WILL PERSIST  
THROUGH TUESDAY MORNING. WIND SPEEDS AND GUSTS WILL DECREASE  
SLIGHTLY TODAY AS THE PRESSURE GRADIENT RELAXES SLIGHTLY AND  
COLD AIR ADVECTION SLOWS. CONDITIONS WILL REMAIN HAZARDOUS FOR  
SMALL CRAFT THROUGH TUESDAY MORNING AT LEAST. WINDS WILL BACK  
SOUTHWESTERLY ON TUESDAY AND WARMER AIR WILL MOVE INTO THE  
REGION. ON WEDNESDAY EVENING AND THURSDAY WINDS WILL VEER  
WESTERLY AND WEAKEN BRINGING AN END TO THE HAZARDOUS CONDITIONS  
FOR A DAY OR TWO. STRONGER WINDS ARE FORECAST TO RETURN BY THE  
WEEKEND.  
 
FOR THE OPEN WATER DISCUSSION, REFER TO THE NWS MARQUETTE AREA  
FORECAST DISCUSSION AT WEATHER.GOV/MQT.  
 
 
   
DLH WATCHES/WARNINGS/ADVISORIES  
 
MN...EXTREME COLD WARNING UNTIL NOON CST TUESDAY FOR MNZ010>012-  
018>021-025-026-033>038.  
WI...EXTREME COLD WARNING UNTIL NOON CST TUESDAY FOR WIZ001>004-  
006>009.  
MARINE...SMALL CRAFT ADVISORY UNTIL 4 AM CST TUESDAY FOR LSZ140>148-150.  
 
 
 
 
 
DISCUSSION...HUYCK  
AVIATION...HUYCK  
MARINE...HUYCK  
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