194  
FXUS63 KDLH 201136  
AFDDLH  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE DULUTH MN  
636 AM CDT THU JUL 20 2017  
   
SHORT TERM
 
(TODAY THROUGH FRIDAY)  
ISSUED AT 328 AM CDT THU JUL 20 2017  
 
AN AREA OF HIGH PRESSURE NEAR THE BORDER BETWEEN NORTH DAKOTA AND  
CANADA WILL SHIFT INTO MINNESOTA TODAY. THE SURFACE RIDGE AXIS  
WILL BE JUST TO THE WEST AND SOUTH OF THE NORTHLAND, SO LIGHT TO  
BREEZY NORTHWEST FLOW WILL DEVELOP BY THIS AFTERNOON. DESPITE THE  
FLOW, THE LACK OF COOL AIR ADVECTION AND RELATIVELY DRY AIR WILL  
MEAN IT WILL EVEN BE DIFFICULT TO PRODUCE ANY CUMULUS. IT SHOULD  
BE A TRULY SUNNY DAY. HIGHS WILL BE IN THE UPPER 70S TO MIDDLE  
80S. SOME OF THE WARMEST AREAS IN THE FORECAST INCLUDE THE LOWER  
ELEVATION AREAS OF DULUTH AND ALONG THE NORTH SHORE BECAUSE OF  
THE TYPICAL DOWNSLOPE WARMING FROM THE NORTHWEST FLOW.  
 
THE SURFACE RIDGE WILL MOVE THROUGH THE NORTHLAND TONIGHT,  
PROMOTING CLEAR SKIES AND CALM CONDITIONS. WINDS AND CLOUD COVER  
WILL BEGIN TO INCREASE FROM THE WEST LATE TONIGHT AS THE SURFACE  
RIDGE DEPARTS AND LOWER PRESSURE APPROACHES FROM THE WEST. THIS  
MEANS THE COOLEST OVERNIGHT TEMPERATURES WILL BE ACROSS THE  
EASTERN FORECAST AREA. LEANED ON THE COOLER MODEL GUIDANCE, SUCH  
AS THE CONSENSUS OF THE GFS MOS AND NAM MOS. LOWS SHOULD RANGE  
FROM THE LOW 50S IN THE ARROWHEAD, TO THE MIDDLE 50S IN NORTHWEST  
WISCONSIN, AND TO UPPER 50S TO LOW 60S FROM CENTRAL TO NORTH-  
CENTRAL MINNESOTA. THERE IS A LOW CHANCE OF SHOWERS AND VERY WEAK  
STORMS (AS SUGGESTED BY THE 00Z GFS) ACROSS THE FAR NORTHWEST  
FORECAST AREA, WEST OF BIGFORK AND INTERNATIONAL FALLS, DUE TO A  
POTENTIAL MID- LEVEL FRONTOGENETICAL BAND AND PASSING WEAK  
SHORTWAVES.  
 
AN AREA OF LOW PRESSURE LEE OF THE ROCKY MOUNTAINS IN THE NORTHERN  
HIGH PLAINS WILL ADVANCE EAST INTO THE DAKOTAS FRIDAY. THE  
ASSOCIATED WARM FRONT WILL BE WELL SOUTH AND WEST OF THE  
NORTHLAND, BUT SOUTH-SOUTHEAST FLOW WILL BRING AN INFLUX OF  
HUMIDITY NORTHWARDS INTO THE NORTHLAND. HOWEVER, THE APPROACHING  
LOW PRESSURE WILL STIMULATE THE TYPICAL EASTERLY, COOL OUTFLOW  
FROM LAKE SUPERIOR. THIS WILL SET UP A STATIONARY BOUNDARY ACROSS  
THE SOUTHERN FORECAST AREA. DAYTIME HEATING WILL BUILD UP  
INSTABILITY FROM THE WEST, WITH AS MUCH AS 500 TO 1500 J/KG OF  
MUCAPE ACROSS THE SOUTHERN AND WESTERN FORECAST AREA. PASSING  
SHORTWAVES AND THE STATIONARY BOUNDARY ACROSS THE SOUTHERN  
FORECAST AREA MAY PROVIDE ENOUGH FORCING TO GENERATE SOME SHOWERS  
AND STORMS. IF STORMS DEVELOP, THEY MAY BECOME ORGANIZED AND  
STRONG THANKS TO PLENTY OF DEEP LAYER WIND SHEAR. THERE WILL  
LIKELY BE AT LEAST 35 TO 45 KNOTS OF 0-6 KM WIND SHEAR. HIGHS  
SHOULD RANGE FROM THE MIDDLE 70S NEAR LAKE SUPERIOR TO THE UPPER  
70S AND LOW 80S INLAND.  
   
LONG TERM
 
(FRIDAY NIGHT THROUGH WEDNESDAY)  
ISSUED AT 328 AM CDT THU JUL 20 2017  
 
A STRONGER SHORTWAVE WILL CONTINUE TO MOVE FROM SOUTHERN  
SASKATCHEWAN FRIDAY EVENING TO THE MANITOBA, NORTHWEST ONTARIO,  
NORTHERN MINNESOTA REGION BY SATURDAY EVENING. A SURFACE LOW AND  
FRONTAL BOUNDARY WILL BE OVER THE NORTHERN PLAINS TO THE SHORTWAVE  
FRIDAY EVENING AND WILL MOVE INTO SOUTHEAST MINNESOTA BUT EXTEND  
NORTHWEST INTO MANITOBA BY 12Z SATURDAY. IT WILL CONTINUE EAST  
SATURDAY INTO SATURDAY NIGHT WITH MUCH OF THE REGION IN A COOLER  
NORTHWEST FLOW BY 12Z SUNDAY PER BOTH THE GFS AND ECMWF. THE NAM  
IS SLOWER.  
 
THERE WILL BE PLENTY OF MOISTURE ACROSS THE REGION FRIDAY NIGHT  
INTO SATURDAY EVENING AS PWAT VALUES RISE TO 1 TO AROUND 1.5  
INCHES...A BIT HIGHER FROM THE NAM. THE INSTABILITY WILL BE ON THE  
INCREASE AS WELL. SHOWERS AND STORMS WILL BE POSSIBLE FRIDAY  
NIGHT BECOMING MORE LIKELY OVERNIGHT INTO SATURDAY AS THE  
SHORTWAVE AND LOW APPROACH THE REGION. THE NAM AND GFS ALSO SHOW  
SOME AREAS OF LOW LEVEL FGEN WHICH WOULD ENHANCE LIFT. THERE ISN'T  
GREAT AGREEMENT BETWEEN THE MODELS ON THE EXACT LOCATION OF THE  
FGEN AND WE MAY HAVE TO WAIT ANOTHER 24 HOURS OR SO TO GET A  
BETTER HANDLE ON WHERE IT WILL SET UP FOR FRIDAY NIGHT. THERE WILL  
BE A CHANCE FOR STRONG TO SEVERE STORMS OVER MUCH OF THE AREA  
FRIDAY NIGHT INTO SATURDAY EVENING. HEAVY RAIN WILL BE AN  
ADDITIONAL THREAT, ESPECIALLY NEAR THE STRONGER LOW LEVEL FGEN.  
 
AS THE LOW AND FRONT PASS THROUGH THE REGION SATURDAY NIGHT INTO  
SUNDAY, COOLER AIR WILL BE MOVING IN AND THE SEVERE THREAT WILL BE  
LOW. SHOWERS AND A FEW STORMS WILL REMAIN POSSIBLE SUNDAY BUT IT  
WILL THEN DRY OUT SUNDAY NIGHT INTO MONDAY AS HIGH PRESSURE  
TEMPORARILY BUILDS IN.  
 
THERE WILL BE CHANCES FOR SHOWERS/STORMS TUESDAY/WEDNESDAY. BOTH  
THE GFS AND ECMWF SHOW A FRONT AND SHORTWAVE MOVING THROUGH THE  
AREA BUT HAVE SOME TIMING DIFFERENCES.  
 
HIGH TEMPERATURES SATURDAY WILL RANGE FROM AROUND 70 IN THE  
ARROWHEAD TO AROUND 80 IN THE BRAINERD LAKES REGION EAST TOWARD  
SIREN. HIGHS SUNDAY WILL BE IN THE LOWER TO MIDDLE SEVENTIES WITH  
TEMPERATURES WARMING TO THE MID TO UPPER SEVENTIES BY NEXT  
WEDNESDAY.  
 

 
   
AVIATION
 
(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING)  
ISSUED AT 636 AM CDT THU JUL 20 2017  
 
HIGH PRESSURE HAS LED TO MOSTLY CLEAR SKIES, CALM WINDS, AND FOG  
OVER THE NORTHLAND EARLY THIS MORNING. THE FOG WILL QUICKLY LIFT  
OVER THE NEXT 1 TO 2 HOURS LEADING TO VFR CONDITIONS INTO THIS  
EVENING. MORE FOG WILL BE POSSIBLE LATER TONIGHT DROPPING THE  
VISIBILITY TO IFR OR MVFR IN SPOTS. IN ADDITION TO THE FOG LATER  
TONIGHT, SOME SHOWERS AND STORMS MAY FORM AS WELL. WE LEFT THE  
MENTION OUT OF THE TAF SITES FOR NOW AND KINL WOULD BE MOST LIKELY  
TO SEE A SHOWER/STORM LATE IN THE PERIOD AND IT MAY NEED TO BE  
ADDED WITH LATER UPDATES.  
 

 
   
PRELIMINARY POINT TEMPS/POPS
 
 
DLH 83 59 78 59 / 0 0 20 20  
INL 76 54 80 59 / 0 10 20 40  
BRD 85 62 81 63 / 0 0 40 30  
HYR 85 55 81 62 / 0 0 30 30  
ASX 85 55 80 58 / 0 0 20 20  
 

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

 
 

 
 
SHORT TERM...GROCHOCINSKI  
LONG TERM...MELDE  
AVIATION...MELDE  
 
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