782  
FXUS63 KDLH 261138  
AFDDLH  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE DULUTH MN  
638 AM CDT WED APR 26 2017  
   
UPDATE
 
 
ISSUED AT 618 AM CDT WED APR 26 2017  
 
PLEASE SEE THE 12Z AVIATION DISCUSSION BELOW.  
 

 
   
SHORT TERM
 
(TODAY THROUGH THURSDAY)  
ISSUED AT 451 AM CDT WED APR 26 2017  
 
A STRONG SURFACE LOW WAS OVER NORTHEAST IOWA EARLY THIS MORNING,  
WITH A WARM FRONT EXTENDING NORTHEAST ACROSS WISCONSIN AND UPPER  
MICHIGAN. A TROUGH EXTENDS NORTHWEST TO WESTERN MINNESOTA AND  
EASTERN NORTH DAKOTA. THIS LOW PRESSURE SYSTEM HAS SPREAD A BROAD  
AREA OF PRECIPITATION ACROSS THE FORECAST AREA, EXTENDING FROM  
SOUTHERN MINNESOTA WELL UP ACROSS THE FORECAST AREA AND AREAS TO  
THE EAST. THIS RAIN IS FALLING INTO NEAR FREEZING SURFACE  
TEMPERATURES, AND WITH TEMPERATURES ALOFT ALSO NEAR FREEZING, WE  
ARE EXPERIENCING A WINTRY MIXTURE OF RAIN, SLEET, FREEZING RAIN  
AND SNOW ACROSS THE FORECAST AREA. IN FACT, A QUICK CHECK OUTSIDE  
SHOWS THAT WE HAVE NOW SHIFTED FROM RAIN TO FREEZING RAIN HERE AT  
THE OFFICE, WITH ICING ON THE FLAG AND FLAG POLE, AND ALSO  
BEGINNING TO DEVELOP ON OTHER ELEVATED SURFACES. THE STRONG  
FRONTOGENESIS AND WARM AIR ADVECTION PRODUCING THIS BAND OF  
PRECIPITATION IS EXPECTED TO CONTINUE TO AFFECT THE FORECAST AREA  
THIS MORNING AND EARLY AFTERNOON, BEFORE BEGINNING TO TAPER OFF  
FROM SOUTHWEST TO NORTHEAST THIS AFTERNOON AND EVENING. BASED ON  
CURRENT SURFACE TEMPERATURES, HAVE DECIDED TO EXPAND THE WINTER  
WEATHER ADVISORY WE HAVE TO THE BRAINERD LAKES AND LEECH LAKES  
AREAS, WHERE TEMPERATURES ARE BELOW FREEZING WITH FREEZING RAIN  
BEING REPORTED INSTEAD OF SNOW. TEMPERATURES MAY WARM BACK ABOVE  
FREEZING LATER TODAY, BUT AM UNCERTAIN OF THAT TIMING SO HAVE JUST  
RUN THAT ADVISORY THROUGH THE DAY TODAY. THE ICE STORM WARNING FOR  
THE FAR NORTHEAST TIP OF THE ARROWHEAD APPEARS TO BE WORKING OUT,  
WITH TEMPERATURES IN THE UPPER 20S AND ONLY SOME AREAS REPORTING  
SNOW. SEVERAL ROAD REPORTS INDICATE ICE COVERED ROADS IN THE ICE  
STORM WARNING AREA, SO HAVE CONTINUED THIS WARNING. EXPECT THE  
AREA OF ICING IS RELATIVELY SMALL, BUT IT WILL BE QUITE  
SIGNIFICANT. THE OTHER WINTER WEATHER ADVISORY AREAS APPEAR TO BE  
ON TRACK FOR NOW, WITH LOCATIONS REPORTING A WINTRY MIXTURE  
OVERNIGHT. WE ARE LIKELY TO LOSE MOST OF OUR ICE ALOFT BY TONIGHT  
WITH THE UPPER LEVEL DRY SLOT MOVING IN, SO THE PRECIPITATION IS  
LIKELY TO EITHER COME TO AN END OR WE WILL HAVE LINGERING FREEZING  
DRIZZLE OR FLURRIES CONTINUE TONIGHT ONCE THE BACK EDGE OF THE  
PRECIPITATION MOVES EAST. PORTIONS OF NORTHWEST WISCONSIN WILL  
STILL BE IN ENOUGH LIFT TO GET MORE SUBSTANTIAL PRECIPITATION, SO  
HAVE DECIDED TO EXPAND THE WINTER WEATHER ADVISORY INTO TONIGHT  
OVER THERE, AND WE MAY NEED TO EXTEND OTHER AREAS AS WELL.  
   
LONG TERM
 
(THURSDAY NIGHT THROUGH TUESDAY)  
ISSUED AT 451 AM CDT WED APR 26 2017  
 
THE LONG-TERM FORECAST CONTINUES TO SHOW INCREASED CHANCES OF A  
WINTRY MIX FOR SUNDAY AND MONDAY, AND SLIGHTLY BELOW AVERAGE  
TEMPERATURES ACROSS THE NORTHLAND.  
 
THURSDAY NIGHT/FRIDAY MORNING WILL HAVE DIMINISHING CHANCES OF  
MAINLY SNOW, WITH POSSIBLY SOME RAIN MIXED IN. THIS PRECIPITATION IS  
ASSOCIATED WITH THE REMNANTS OF THE CURRENT SYSTEM AS ANALYSIS OF  
THE 500 MB HEIGHTS INDICATE MAIN SHORTWAVE ASSOCIATED WITH WHAT'S  
CURRENTLY IMPACTING THE NORTHLAND TO BECOME CUT-OFF ALOFT, WHICH  
WOULD SLOW DOWN ITS PROPAGATION DOWNSTREAM. THE GENERAL CONSENSUS IN  
THE MODELS IS THAT THE QPF AMOUNTS WITH THE REMNANTS OF THIS SYSTEM  
WILL BE LIGHT IN NATURE. SO, ANY SNOWFALL DURING THIS TIME PERIOD  
WOULD ALSO REMAIN LIGHT. BY FRIDAY AFTERNOON/EVENING, PRECIPITATION  
WILL BE OUT OF THE AREA. LOW TEMPERATURES FRIDAY MORNING WILL BE  
BELOW FREEZING ACROSS THE REGION, WITH HIGHS REBOUNDING INTO THE 40S  
BY THE AFTERNOON.  
 
SATURDAY LOOKS DRY AT THIS POINT, WITH MOSTLY SUNNY SKIES EARLY, AS  
A LOW-AMPLITUDE MID-LEVEL RIDGE TRANSLATES OVER THE REGION. THERE  
WILL BE SOME INCREASING CLOUDS FROM THE SOUTH AHEAD OF THE NEXT  
SYSTEM THAT COULD IMPACT THE REGION SUNDAY AND MONDAY. A POTENT MID-  
LEVEL SHORTWAVE THAT DEVELOPS OUT OF THE FOUR-CORNERS REGION OF THE  
INTERMOUNTAIN WEST STATES UNDERGOES LEE CYCLOGENESIS AND ASCENDS  
NORTHEAST TOWARDS THE WESTERN GREAT LAKES. NORTHWEST WISCONSIN AND  
ADJACENT AREAS OF NORTHEAST MINNESOTA AND LAKE SUPERIOR SHOULD BE  
THE MOST LIKELY TO SEE ANY PRECIPITATION FROM THIS SYSTEM AS THIS IS  
WHERE THE BEST ISENTROPIC LIFT WOULD CORRESPOND. HOWEVER, THERE IS  
STILL SOME UNCERTAINTY REGARDING P-TYPES AS THE GFS/ECMWF/CMC MODELS  
ARE ALL SHOWING THERMAL PROFILES AT OR NEAR THE 0 DEGREE C ISOTHERM.  
ANY LITTLE CHANGE IN THE THERMAL PROFILE WOULD CHANGE P-TYPES  
DRASTICALLY. THIS SYSTEM WILL NEED TO BE WATCHED AS A WINTRY MIX  
WILL BE POSSIBLE. FOR NOW, THE GFS SOUNDINGS ARE SUGGESTING MORE OF  
A RAIN/SNOW MIX. MOREOVER, THE MODELS DISAGREE ON QPF AMOUNTS AND  
SYSTEM DURATION, SO STILL PLENTY OF UNCERTAINTY WITH THIS. THE  
26.00Z GFS IS THE QUICKEST WITH TAKING THE PRECIPITATION SHIELD TO  
THE EAST BY 06Z TUESDAY, FOLLOWED BY THE CMC MODEL BY 12Z TUESDAY,  
AND THEN THE ECMWF BY 00-06Z WEDNESDAY, SO IT'S DIFFICULT TO PIN  
DOWN EXACT TIMING THIS FAR OUT.  
 
BEYOND TUESDAY, MUCH UNCERTAINTY EXISTS BETWEEN THE SYNOPTIC MODELS  
AS THE GFS BRINGS IN ANOTHER SHOT OF PRECIPITATION, BUT THE  
ECMWF/CMC MODELS KEEP US DRY.  
 

 
   
AVIATION
 
(FOR THE 12Z TAFS THROUGH 12Z THURSDAY MORNING)  
ISSUED AT 618 AM CDT WED APR 26 2017  
 
AN AREA OF LOW PRESSURE WILL CONTINUE TO MOVE THROUGH SOUTHWEST  
AND CENTRAL WISCONSIN TODAY, BRINGING A WINTRY MIX ACROSS THE  
NORTHLAND TAF TERMINALS. MVFR/IFR/LIFR CEILINGS AND VISIBILITIES  
HAVE BEEN OBSERVED THROUGHOUT THE MORNING AND WILL CONTINUE  
THROUGH THE REMAINDER OF THE MORNING. -FZRA HAS BEEN THE MOST  
COMMON PRECIP. TYPE, WITH THE EXCEPTION FOR -SN AT KINL.  
PRECIPITATION SHOULD DIMINISH LATER THIS AFTERNOON AS THE  
PRECIPITATION SHIELD LIFTS TO THE NORTH. NORTHEAST WINDS WILL  
REMAIN GUSTY TODAY, WITH GUSTS BETWEEN 20 TO 25 KTS POSSIBLE.  
 

 
   
PRELIMINARY POINT TEMPS/POPS
 
 
DLH 33 23 34 25 / 100 50 40 20  
INL 29 21 32 24 / 90 50 50 40  
BRD 35 24 39 27 / 100 50 20 10  
HYR 39 27 38 26 / 90 50 40 20  
ASX 35 27 37 27 / 100 60 60 20  
 

 
   
DLH WATCHES/WARNINGS/ADVISORIES
 
 
WI...WINTER WEATHER ADVISORY UNTIL 7 PM CDT THIS EVENING FOR WIZ001-  
002.  
 
WINTER WEATHER ADVISORY FROM 7 PM THIS EVENING TO 10 AM CDT  
THURSDAY FOR WIZ003-004.  
 
MN...WINTER WEATHER ADVISORY UNTIL 7 PM CDT THIS EVENING FOR MNZ010-  
011-018>020-025-026-033>037.  
 
ICE STORM WARNING UNTIL 10 PM CDT THIS EVENING FOR MNZ012-021.  
 
LS...GALE WARNING UNTIL 10 PM CDT THIS EVENING FOR LSZ121-140>148.  
 

 
 

 
 
UPDATE...JTS  
SHORT TERM...LE  
LONG TERM...JTS  
AVIATION...JTS  
 
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