420  
FXUS63 KDLH 042334  
AFDDLH  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE DULUTH MN  
634 PM CDT SAT APR 4 2020  
   
SHORT TERM
 
(THIS EVENING THROUGH SUNDAY NIGHT)  
ISSUED AT 308 PM CDT SAT APR 4 2020  
 
QUIET CONDITIONS WILL CONTINUE TONIGHT THROUGH SUNDAY AFTERNOON  
BEFORE CHANCES OF A RAIN/SNOW MIX RETURNS TO THE NORTHLAND FOR  
SUNDAY EVENING.  
 
THIS AFTERNOON AND EVENING WILL FIND SURFACE HIGH PRESSURE, ALONG  
WITH AN 850 MB RIDGE AXIS PASSING THROUGH THE REGION. AS THE HIGH  
PRESSURE PASSES THROUGH TONIGHT, SOME AREAS COULD DIP DOWN INTO THE  
LOWER TO MIDDLE TEENS FOR LOWS DUE TO STRONG RADIATIONAL COOLING,  
THANKS TO CLEAR SKIES AND LIGHT WINDS. WE LEANED TOWARDS THE 10TH  
PERCENTILE FOR TONIGHT'S LOWS, WITH THE COLDEST TEMPERATURES  
EXPECTED OVER THE MINNESOTA ARROWHEAD AND NORTHWEST WISCONSIN. AS  
THE HIGH PRESSURE RIDGE PASSES BY TO THE EAST LATE TONIGHT AND  
AROUND SUNRISE, A STREAM OF CHANNELED VORTICITY WILL SKIM OUR  
NORTHERN AREAS, ALONG WITH INCREASING WARM AIR ADVECTION WHICH MAY  
RESULT IN SOME LIGHT SNOW FLURRIES OVER KOOCHICHING COUNTY. THIS  
ACTIVITY WILL REMAIN LIGHT, AND NO ACCUMULATION IS ANTICIPATED.  
 
SUNDAY WILL BE WARMER COMPARED TO TODAY, THANKS TO ENHANCED WARM AIR  
ADVECTION DUE TO SOUTHERLY FLOW. SUNDAY WILL BE A LITTLE BREEZIER  
THAN TODAY, WITH SUSTAINED WINDS BETWEEN 5 TO 15 MPH, AND GUSTS UP  
TO 20 MPH. SUNDAY'S HIGHS WILL WARM INTO THE LOWER TO MIDDLE 50S. IT  
WILL BE COOLER BY THE LAKE, THANKS TO THIS SOUTHERLY FLOW, WITH  
AREAS NEAR GRAND MARAIS, ONLY WARMING TO THE LOWER 40S. THEN,  
CHANCES OF A RAIN/SNOW MIX WILL INCREASE SUNDAY EVENING AS A SHALLOW  
MID-LEVEL SHORTWAVE AND LOW-LEVEL WARM AIR ADVECTION WILL BRING  
STRONGER LIFT TO THE REGION. ANY ACCUMULATIONS THAT RESULT FROM THE  
SNOW SHOULD BE LIGHT, WITH ONLY UP TO A HALF-INCH POSSIBLE OVER LAKE  
AND COOK COUNTIES, WITH LIGHTER AMOUNTS ELSEWHERE OVER NORTH-CENTRAL  
MINNESOTA.  
   
LONG TERM
 
(MONDAY THROUGH SATURDAY)  
ISSUED AT 328 PM CDT SAT APR 4 2020  
 
EARLY IN THE WORK WEEK, A BAROCLINIC ZONE DRAPED FROM NORTH DAKOTA  
EAST ACROSS THE FORECAST AREA INTO NORTHERN WISCONSIN WILL INTERACT  
WITH AN INVERTED TROUGH AND A WEAK SHORTWAVE ALOFT TO BRING  
PRECIPITATION CHANCES TO THE AREA FOR MONDAY. WHILE THE TROUGH  
SLIDES OFF TO THE EAST, THE BAROCLINIC ZONE REMAINS, AND A  
SHORTWAVE BEGINS MOVING IN ALOFT TO BRING MORE CHANCES FOR  
PRECIPITATION TO THE AREA FOR MONDAY NIGHT AND ESPECIALLY ON  
TUESDAY. GIVEN THE SET-UP, IT IS NO SURPRISE TO SEE SOME  
POTENTIAL FOR RUMBLES OF THUNDER ON MONDAY AFTERNOON AND NIGHT, AS  
WELL AS TUESDAY WHEN THE BETTER UPPER LEVEL DYNAMICS WITH  
STEEPENING DEEP LEVEL LAPSE RATES MOVE THROUGH. OVERNIGHT LOWS  
CURRENTLY FORECAST FOR MONDAY NIGHT SHOW THAT THERE MAY BE SOME  
MIXED PRECIPITATION FOR THE ARROWHEAD, BUT CONFIDENCE IS NOT VERY  
HIGH IN THIS, AND WE MAY END UP REMOVING IT AS WE GET CLOSER IN  
TIME. NORTHEAST FLOW AND CLOUD COVER SHOULD KEEP MONDAY ON THE  
COOL SIDE, BUT WARM AIR PUSHING INTO THE AREA FROM THE SOUTHWEST  
ON TUESDAY SHOULD ALLOW AT LEAST PART OF THE AREA TO GET PRETTY  
WARM, WITH HIGHS APPROACHING 60 FOR AREAS SOUTH OF HIGHWAY 2.  
 
THE PATTERN REMAINS ACTIVE FOR THE AREA INTO NEXT WEEKEND. THE  
UPPER LOW THAT FIRST SHOVED A SHORTWAVE AT US FOR TUESDAY PUSHES  
CLOSER TO THE AREA FOR WEDNESDAY, AND BRING MORE CHANCES FOR  
PRECIPITATION. IT WILL BE ACCOMPANIED BY A COLD FRONT THAT MOVES  
THROUGH THE AREA DURING THE DAYTIME. THERE IS SOME POTENTIAL FOR  
MORE THUNDER CHANCES AS WE SHOULD BE IN THE WARM SECTOR AHEAD OF THE  
FRONT AND THERE WILL BE SOME DECENT DYNAMICS WITH THIS WAVE, BUT  
HAVE LEFT THESE OUT FOR NOW, AND WE WILL HAVE TO RE-EVALUATE THAT  
AS WE GET CLOSER. THE CLOUDS AND PRECIPITATION SHOULD PRODUCE  
COOLER TEMPERATURES THAN TUESDAY, ESPECIALLY AS THE WARM SECTOR IS  
PUSHED EAST FAIRLY QUICKLY DURING THE DAYTIME. THE UPPER LEVEL  
LOW SETTLES OVER/EAST OF THE AREA FOR THURSDAY, BRINGING A COLD  
POOL AT 850MB OVER THE AREA, AND DEEP CYCLONIC FLOW OVER THE AREA.  
THIS SHOULD PRODUCE INSTABILITY SHOWERS BOTH THURSDAY AND FRIDAY,  
AND HAVE KEPT TO CHANCES OR SLIGHT CHANCES FOR BOTH DAYS.  
THURSDAY WILL BE THE COOLEST DAY OF THE WEEK WITH HIGHS ONLY IN  
THE 40S. TEMPERATURES WILL MODERATE INTO THE WEEKEND AS THE UPPER  
LOW PULLS OFF TO THE EAST, ALLOWING WARMER AIR TO MOVE INTO THE  
AREA.  
 

 
   
AVIATION
 
(FOR THE 00Z TAFS THROUGH 00Z SUNDAY EVENING)  
ISSUED AT 633 PM CDT SAT APR 4 2020  
 
VFR CONDITIONS CONTINUE THROUGH THIS EVENING. HIGH PRESSURE WILL  
SLOWLY DRIFT EAST THROUGH THE FORECAST PERIOD AND SOME HIGH CIRRUS  
CLOUDS WILL BE POSSIBLE TONIGHT. A VERY WEAK WAVE MAY PASS THROUGH  
NORTH CENTRAL MN TOMORROW MORNING GIVING WAY TO LIGHT SNOW SHOWERS  
WITH CEILINGS EXPECTED TO REMAIN VFR. LOOK FOR WIND GUSTS BETWEEN 15-  
20KTS AT SOME LOCATIONS BY MID MORNING AS THE HIGH PRESSURE BEGINS  
TO EXIT THE NORTHLAND.  
 

 
   
MARINE
 
 
ISSUED AT 308 PM CDT SAT APR 4 2020  
 
SOUTHWEST WINDS WILL REMAIN FAIRLY LIGHT, GENERALLY BETWEEN 5 TO 15  
KNOTS, THROUGH THE AFTERNOON, WEAKENING FURTHER THIS EVENING AS AN  
AREA OF HIGH PRESSURE BUILDS ACROSS WESTERN LAKE SUPERIOR. WINDS  
TURN MORE SOUTHEASTERLY SUNDAY MORNING, THEN TURN MORE  
NORTHWESTERLY BY THE AFTERNOON, GENERALLY BETWEEN 5 TO 10 KNOTS.  
AN APPROACHING AREA OF LOW PRESSURE WILL BE THE CAUSE FOR THE  
EASTERLY WINDS, AND THEY WILL CONTINUE INTO EARLY NEXT WEEK AND  
MAY INCREASE TO 10 TO 15 KNOTS WITH HIGHER GUSTS MONDAY AND  
TUESDAY, ESPECIALLY OVER THE FAR SOUTHWEST ARM OF THE LAKE. A FEW  
THUNDERSTORMS WILL BE POSSIBLE FOR MONDAY NIGHT AND TUESDAY. NO  
SEVERE WEATHER IS ANTICIPATED. A COLD FRONT WILL PASS THROUGH THE  
REGION TUESDAY EVENING, CAUSING WINDS TO BECOME WEST/NORTHWEST.  
THESE WINDS SHOULD STRENGTHEN AND COULD LEAD TO CONDITIONS  
HAZARDOUS TO SMALL CRAFT ON WEDNESDAY.  
 

 
   
PRELIMINARY POINT TEMPS/POPS
 
 
DLH 20 49 31 43 / 0 0 20 50  
INL 17 51 30 50 / 10 10 40 20  
BRD 22 56 36 56 / 0 0 30 30  
HYR 17 55 35 54 / 0 0 10 50  
ASX 17 54 33 49 / 0 0 20 50  
 

 
   
DLH WATCHES/WARNINGS/ADVISORIES
 
 
WI...NONE.  
MN...NONE.  
LS...NONE.  

 
 

 
 
SHORT TERM...JTS  
LONG TERM...LE  
AVIATION...BRITT  
MARINE...JTS  
 
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