648  
FXUS63 KDLH 161144  
AFDDLH  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE DULUTH MN  
644 AM CDT TUE JUL 16 2019  
   
SHORT TERM
 
(TODAY THROUGH WEDNESDAY)  
ISSUED AT 329 AM CDT TUE JUL 16 2019  
 
DRIER CONDITIONS ARE EXPECTED FOR TODAY, WITH ANOTHER ROUND OF  
SHOWERS AND THUNDERSTORMS POSSIBLE FOR WEDNESDAY, SOME OF WHICH  
COULD BE STRONG TO SEVERE.  
 
THE COLD FRONT THAT SUPPORTED THE THUNDERSTORMS FROM YESTERDAY  
WILL SLOWLY MAKE ITS WAY SOUTHEASTWARD, AND EVENTUALLY STALL OVER  
WEST-CENTRAL WISCONSIN. SOUTHWEST FLOW ALOFT WILL CONTINUE THROUGH  
THE DAY TODAY, WHICH WILL ALLOW A MID-LEVEL IMPULSE TO SWEEP  
THROUGH THE NORTHLAND. THERE IS SOME TIMING DIFFERENCES AMONG THE  
GFS AND NAM MODELS, BUT THE SOUNDINGS BOTH SHOW A FAIRLY DRY AIR  
MASS SETTLING INTO THE REGION. THUS, WE HAVE PULLED THE SMALL POPS  
ACROSS OUR SOUTH FROM THE FORECAST. THE MAIN STORY FOR TODAY WILL  
CONTINUE TO BE WARM TEMPERATURES, WITH HIGHS IN THE LOWER TO  
MIDDLE 80S. THERE WILL BE A RESPITE FROM THE MUGGY CONDITIONS  
TODAY, WITH DECREASING DEW POINT TEMPERATURES INTO THE UPPER 50S  
TO LOWER 60S, MUCH LOWER COMPARED TO THE LAST FEW DAYS. HEAT  
INDICIES COULD STILL APPROACH 90 F OVER NORTHWEST WISCONSIN TODAY  
UNDER PARTLY TO MOSTLY SUNNY SKIES.  
 
ATTENTION THEN TURNS TO INCREASING CHANCES OF SHOWERS AND  
THUNDERSTORMS FOR LATE TONIGHT THROUGH THE DAY WEDNESDAY. A LARGE  
AREA OF HIGH PRESSURE WILL BUILD OVER CENTRAL ONTARIO, WITH AN  
APPROACHING SURFACE LOW PRESSURE SYSTEM OVER THE CENTRAL GREAT  
PLAINS. THIS WILL BRING A MORE EAST TO SOUTHEAST FLOW OVER THE  
REGION. SOUTHWEST FLOW ALOFT WILL PERSIST WEDNESDAY, WHICH WILL  
ALLOW A COUPLE OF MID-LEVEL SHORTWAVES TO TRANSLATE THROUGH THE  
REGION. INSTABILITY IS PROGGED TO INCREASE FROM THE SOUTHWEST  
WEDNESDAY AFTERNOON, WITH MODEST MIXED-LAYER CAPE VALUES IN THE  
500 TO 1500 J/KG RANGE. EFFECTIVE BULK SHEAR VALUES WILL BE  
IMPRESSIVE, WITH VALUES RANGING BETWEEN 40 TO 50 KNOTS BY  
WEDNESDAY EVENING. THERE IS SOME UNCERTAINTY ON HOW THIS SCENARIO  
WILL PLAY OUT GIVEN DIFFERENCES AMONG THE DETERMINISTIC GUIDANCE,  
BUT WITH THE MORE FAVORABLE INSTABILITY REMAINING TO THE SOUTH,  
THE STORM PREDICTION CENTER ONLY HAS A MARGINAL RISK OF SEVERE  
STORMS ACROSS OUR SOUTHERN TIER OF COUNTIES. EXPECT SOME COOLER  
TEMPERATURES ALONG LAKE SUPERIOR ON WEDNESDAY DUE TO NORTHEAST  
FLOW. HIGHS WEDNESDAY ALONG THE LAKE WILL BE IN THE UPPER 60S TO  
LOWER 70S, WITH HIGHS IN THE LOWER 80S FARTHER INLAND. WINDS  
SHOULD BE BREEZY FOR WEDNESDAY, GIVEN THE TIGHT SURFACE PRESSURE  
GRADIENT, WITH GUSTS BETWEEN 15 TO 20 MPH OVER NORTHEAST  
MINNESOTA.  
   
LONG TERM
 
(WEDNESDAY NIGHT THROUGH MONDAY)  
ISSUED AT 329 AM CDT TUE JUL 16 2019  
 
A SHORTWAVE WILL CONTINUE TO MOVE THROUGH THE REGION WEDNESDAY  
NIGHT, ALTHOUGH THE BULK OF THE WAVE WILL BE LIFTING INTO NORTHWEST  
ONTARIO. HOWEVER, A VERY MOIST AIRMASS WILL BE IN PLACE WITH PWAT  
VALUES 1.7-2.0 INCHES. VERY UNSTABLE AIR WILL BE JUST SOUTH OF THE  
NORTHLAND, BUT THERE WILL BE INCREASING INSTABILITY FROM SOUTH TO  
NORTH THROUGH THE EVENING HOURS. SHOWERS AND THUNDERSTORMS WILL  
BE ONGOING EARLY IN THE EVENING AND BECOME BETTER ORGANIZED  
OVERNIGHT. MUCH OF THE GUIDANCE IS IN AGREEMENT THAT THERE IS  
POTENTIAL FOR HEAVY RAINFALL. GIVEN THERE IS ADEQUATE SHEAR WITH  
500MB WINDS OF 40-50 KNOTS, THERE WILL BE AT LEAST A LOW THREAT  
OF SEVERE STORMS, AND IF BETTER INSTABILITY GETS FURTHER NORTH,  
WE COULD SEE A LINE OF STRONG TO SEVERE STORMS WITH A DAMAGING  
WIND THREAT. THE NAMNEST SUGGESTS THIS IS A POSSIBILITY. ONE THING  
THAT COULD LIMIT THE FLASH FLOOD THREAT WOULD BE THE PROGRESSIVE  
NATURE OF THE STORMS WEDNESDAY NIGHT IF THE NAMNEST IS CORRECT.  
HOWEVER, STRONG MOISTURE TRANSPORT INTO THE NORTHLAND MAY CAUSE  
THE STORMS TO BE MORE WIDESPREAD VERSUS THE LINEAR MODE FORECAST  
BY THE NAMNEST/ARW/NMM.  
 
A FAST WEST/SOUTHWEST FLOW ALOFT WILL THEN OCCUR ACROSS THE REGION  
INTO THE EARLY PART OF THE WEEKEND WHEN ANOTHER STRONGER SHORTWAVE  
WILL ARRIVE. THERE ARE SOME TIMING AND STRENGTH DIFFERENCES WITH  
THIS WAVE, THE GFS AND CANADIAN ARE MUCH STRONGER THAN THE ECMWF AND  
THE GFS IS SLOWER. WE HAVE PERIODIC CHANCES FOR THUNDERSTORMS  
THROUGH THE WEEKEND, BUT THERE WILL BE SOME DRY PERIODS IN THERE  
AS WELL. TEMPERATURES WILL BE WARMEST THURSDAY AND FRIDAY WITH  
HIGHS IN THE LOWER EIGHTIES TO AROUND NINETY THEN COOL SOME OVER  
THE WEEKEND CLOSER TO NORMAL VALUES.  
 
THE PATTERN WILL SHIFT FROM THE FAST WEST/SOUTHWEST FLOW ALOFT TO  
NORTHWEST FLOW EARLY NEXT WEEK AND THAT WILL LAST WELL INTO THE  
WEEK. THIS WILL MEAN TEMPERATURES WILL BE CLOSER TO NORMAL. THERE  
WILL STILL BE A FEW CHANCES FOR SHOWERS/STORMS BUT CHANCES WILL BE  
BETTER TO STRING A FEW DRY DAYS TOGETHER AS WELL.  
 

 
   
AVIATION
 
(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING)  
ISSUED AT 643 AM CDT TUE JUL 16 2019  
 
PATCHY FOG WILL LIFT BY 14Z AND AN AREA OF LOW MVFR AND IFR  
CEILINGS FROM PINE COUNTY INTO NORTHERN WISCONSIN WILL ALSO  
DISSIPATE BETWEEN 13Z-16Z. THEN EXPECT VFR CONDITIONS INTO THIS  
EVENING WITH SOME SCATTERED TO BRIEFLY BROKEN VFR CUMULUS. THERE  
MAY BE SOME PATCHY FOG AGAIN TONIGHT. WE DO EXPECT SOME SHOWERS  
AND THUNDERSTORMS LATER TONIGHT BUT WE ONLY MENTIONED VCSH AT KHIB  
AND KBRD FOR NOW AS COVERAGE IS EXPECTED TO BE LIMITED. LATER  
UPDATES WILL REFINE THE TIMING.  
 

 
   
MARINE
 
 
ISSUED AT 329 AM CDT TUE JUL 16 2019  
 
WINDS WILL BE WEST TO SOUTHWEST AT 7 TO 15 KNOTS TODAY BUT MAY TURN  
NORTHWEST FOR A TIME ALONG THE NORTH SHORE THIS MORNING. HIGH  
PRESSURE WILL BUILD JUST EAST OF LAKE SUPERIOR TONIGHT AND LOW  
PRESSURE WILL MOVE TOWARD THE NORTH PLAINS LATER TONIGHT INTO  
WEDNESDAY. THIS WILL CAUSE THE WIND TO SWITCH TO EASTERLY TONIGHT  
AND FOR SPEEDS TO INCREASE, ESPECIALLY OVER THE FAR SOUTHWEST ARM  
OF THE LAKE. WINDS THERE MAY BE 15 TO 20 KNOTS FOR A TIME LATE  
TONIGHT INTO WEDNESDAY AND A SMALL CRAFT ADVISORY MAY BE NEEDED.  
CHANCES FOR THUNDERSTORMS WILL INCREASE AGAIN LATE TONIGHT BUT  
ESPECIALLY WEDNESDAY INTO WEDNESDAY NIGHT. SOME OF THE STORMS  
COULD BE STRONG.  
 

 
   
PRELIMINARY POINT TEMPS/POPS
 
 
DLH 85 61 74 61 / 0 20 60 70  
INL 82 59 80 60 / 0 20 70 70  
BRD 85 66 83 67 / 0 50 70 50  
HYR 86 64 83 68 / 10 20 60 70  
ASX 87 61 78 65 / 10 20 50 70  
 

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

 
 

 
 
SHORT TERM...JTS  
LONG TERM...MELDE  
AVIATION...MELDE  
MARINE...MELDE  
 
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