538  
FXUS63 KDLH 270033  
AFDDLH  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE DULUTH MN  
733 PM CDT FRI MAY 26 2017  
   
UPDATE
 
 
ISSUED AT 722 PM CDT FRI MAY 26 2017  
 
HAVE UPDATED THE FORECAST FOR THE LATEST RADAR TRENDS, AS STORMS  
ARE MAINTAINING LONGER BUT ARE WEAKER THAN THEY WERE EARLIER THIS  
AFTERNOON.  
 

 
   
SHORT TERM
 
(THIS EVENING THROUGH SATURDAY)  
ISSUED AT 354 PM CDT FRI MAY 26 2017  
 
A SURFACE TROF OF LOW PRESSURE WAS MOVING INTO ST.LOUIS COUNTY  
SOUTHWEST THROUGH AITKIN COUNTY AT 1920Z. A LINE OF SHOWERS AND  
ISOLATED THUNDERSTORMS WERE OCCURRING ALONG AN AHEAD OF THIS TROF.  
FOLLOWED THE 17Z HRRR FOR TIMING OF THIS ACTIVITY THROUGH THE  
FORECAST AREA. THE HRRR HAS BEEN DOING A REASONABLE JOB WITH THIS  
ACTIVITY FOR THE LAST COUPLE OF RUNS. STORMS SHOULD EXTEND FROM ELY  
TO THE TWIN PORTS TO PINE CITY BY 22Z/5PM, THE ARROWHEAD TO THE  
HAYWARD LAKES BY 01Z/8PM, AND COME TO AN END BY 03Z/10PM. THE  
SURFACE TROF WILL HAVE MOVED EAST OF THE REGION SHORTLY THEREAFTER,  
AND WITH THE LOSS OF DIURNAL HEATING, NO ADDITIONAL PRECIPITATION IS  
EXPECTED. AFTER 06Z, LOOK FOR FOG TO DEVELOP OVER THE EASTERN TWO  
THIRDS OF THE AREA WITH LIGHT WINDS AND A CLEARING SKY. THE FOG  
SHOULD ERODE BY 9AM SATURDAY.  
 
THE FORECAST AREA WILL ENJOY A BREAK FROM THE RAIN FOR MOST OF THE  
DAY SATURDAY. BY AFTERNOON, SHOWERS ARE EXPECTED TO DEVELOP IN  
RESPONSE TO A LONG WAVE TROF THAT IS PROGGED TO BE FOUND FROM  
NORTHEAST MINNESOTA SOUTHWESTWARD TO EASTERN SOUTH DAKOTA BY 00Z  
SUNDAY. THE SHOWERS WILL BE FOUND PRIMARILY FROM THE BORDERLAND  
SOUTHWEST TO NORTHERN CASS COUNTY, WITH ISOLATED THUNDERSTORMS  
POSSIBLE IN THE LATE AFTERNOON. MAX TEMPS WILL BE IN THE 60S NEAR  
LAKE SUPERIOR, TO THE LOWER 70S INLAND.  
   
LONG TERM
 
(SATURDAY NIGHT THROUGH FRIDAY)  
ISSUED AT 354 PM CDT FRI MAY 26 2017  
 
A CUTOFF UPPER LOW WILL KEEP PARTLY CLOUDY SKIES AND OCCASIONAL RAIN  
CHANCES IN THE PICTURE SATURDAY NIGHT THROUGH MIDWEEK.  
 
SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS SHOULD BE ONGOING IN  
OUR WESTERN ZONES SATURDAY EVENING ASSOCIATED WITH AN APPROACHING  
COOL FRONT. SHOWERS WILL WEAKEN OVERNIGHT WITH ANOTHER ROUND OF  
SHOWERS AND STORMS EXPECTED ON SUNDAY. A FEW STRONG STORMS ARE  
POSSIBLE AS NAM/GFS/GEM PROFILES INDICATE 1-1.5 KJ/KG OF MUCAPE  
DURING THE AFTERNOON. THE STRONGEST SIGNAL FOR POTENT THUNDERSTORMS  
IS OVER NORTHWEST WISCONSIN, BUT PORTIONS OF THE ARROWHEAD MAY ALSO  
SEE A FEW STRONG STORMS. MOST OF THE DETERMINISTIC GUIDANCE FEATURES  
A COMPACT AND RELATIVELY STRONG VORT MAX AND SHORTWAVE TROUGH MOVING  
THROUGH THE NORTHLAND SUNDAY AFTERNOON AND EVENING. THE GFS SEEMS TO  
CARRY THE BEST SIGNAL FOR STRONG STORMS WITH THE VORT MAX ROTATING  
THROUGH THE AREA DURING THE LATE MORNING THROUGH MID-AFTERNOON  
TIMEFRAME. THE GEM IS SIMILAR, BUT A LITTLE SLOWER AND A FEW MILES  
FARTHER NORTH WHILE THE NAM AND ECMWF HAS A MUCH LESS DEFINED  
FEATURE IN THE VICINITY.  
 
THE CLOSED LOW WILL WOBBLE SOUTHEASTWARD TOWARD NORTHERN LAKE  
SUPERIOR SUNDAY NIGHT AND MONDAY. SEVERAL VORTICITY MAXIMA WILL MOVE  
ACROSS MINNESOTA AND WISCONSIN, AND ALONG WITH CONTINUED COLD AIR  
ADVECTION ALOFT, SHOULD SUPPORT NUMEROUS SHOWERS MONDAY, AND A  
CHANCE OF ISOLATED THUNDERSTORMS. A CHANCE OF SCATTERED SHOWERS WILL  
CONTINUE OFF AND ON THROUGH WEDNESDAY NIGHT AS THE CLOSED LOW  
CONTINUES DRIFTING TOWARD NEW ENGLAND AND GRADUALLY FILLS. HIGH  
PRESSURE RETURNS WEDNESDAY NIGHT INTO THE WEEKEND.  
 
TEMPERATURES WILL BE NEAR TO SLIGHTLY ABOVE NORMAL WITH HIGHS IN THE  
UPPER 60S AND LOW 70S AND OVERNIGHT LOWS IN THE 40S AND UPPER 30S. A  
LAKE BREEZE WILL BE PRESENT SOME AFTERNOONS LIMITING TEMPERATURES  
NEAR LAKE SUPERIOR.  
 

 
   
AVIATION
 
(FOR THE 00Z TAFS THROUGH 00Z SATURDAY EVENING)  
ISSUED AT 722 PM CDT FRI MAY 26 2017  
 
INITIAL BAND OF SHOWERS AND THUNDERSTORMS ONLY AFFECTING KHYR  
UNTIL APPROXIMATELY 02Z THIS EVENING, THEN MOVING EAST AND LEAVING  
ALL THE TERMINALS DRY THROUGH THE REMAINDER OF THE TAF PERIOD. DUE  
TO RECENT RAINFALL AND LIGHT WINDS FOG IS POSSIBLE AT KDLH, KHIB  
AND KHYR BETWEEN 08Z AND 11Z, AND HAVE ONLY PUT IN MVFR  
VISIBILITIES FOR NOW. CONVECTION MAY REDEVELOP TO AFFECT KINL AND  
KBRD AFTER 18Z, BUT CONFIDENCE IN TIMING AND COVERAGE IS LOW AND  
HAVE LEFT OUT FOR NOW.  
 

 
   
PRELIMINARY POINT TEMPS/POPS
 
 
DLH 47 70 48 64 / 30 10 30 60  
INL 46 71 46 63 / 0 20 30 50  
BRD 48 72 49 67 / 0 10 20 40  
HYR 48 72 49 68 / 70 10 30 50  
ASX 48 71 49 66 / 70 10 30 50  
 

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

 
 

 
 
UPDATE...LE  
SHORT TERM...GSF  
LONG TERM...HUYCK  
AVIATION...LE  
 
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