668  
FXUS63 KMKX 081102  
AFDMKX  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE MILWAUKEE/SULLIVAN WI  
602 AM CDT WED APR 8 2020  
   
UPDATE
 
MOST VSBYS WITHIN THE CWA 1/4 MILE OR LESS, SO ADVISORY  
CONTINUES.  
 
PC  
 

 
   
AVIATION(12Z TAFS)
 
WILL HAVE A GOOD DEAL OF LIFR CONDITIONS  
THROUGH EARLY MORNING DUE TO DENSE FOG. EVEN SOME VLIFR. EXPECTING  
IMPROVEMENT FROM MID MORNING ON, WITH CEILINGS TRANSITIONING TO  
MVFR AND PERHAPS VFR. RAIN CHANCES INCREASE INTO THE AFTERNOON AHEAD  
OF A FRONTAL BOUNDARY, SO A RETURN OF SOME MVFR CIGS/VSBYS. THIS  
FRONT GOES BY EARLY/MID AFTERNOON. ANY LINGERING RAIN CLEARS OUT  
IN THE EVENING.  
 
PC  
 

 
   
PREV DISCUSSION
 
(ISSUED 353 AM CDT WED APR 8 2020)  
 
SHORT TERM...  
 
TODAY AND TONIGHT...FORECAST CONFIDENCE IS MEDIUM.  
 
AN EARLY MORNING LIGHT WIND REGIME WITH HIGH PRESSURE HAS  
RESULTED IN AREAS OF DENSE FOG. HAVE PUT OUT A DENSE FOG ADVISORY  
FOR THE WHOLE AREA AND WILL RUN THIS THROUGH 14Z.  
 
WITH SOME SUNSHINE AND PRESENCE OF LOW LEVEL THERMAL RIDGE WILL  
KEEP WARM TEMPS GOING. HOWEVER, SHOULD ANY STRATUS NOT ERODE  
THOSE TEMPS WILL BE IN JEOPARDY.  
 
AS LOW LEVEL FRONTOGENETICAL FORCING INCREASES THIS AFTERNOON AND  
EVENING, ALONG WITH MID LEVEL SHORTWAVE ENERGY, EXPECTING RAIN TO  
SPREAD INTO THE AREA. THAT SHOULD CLEAR OUT FAIRLY QUICK THIS  
EVENING, WITH NORTHWEST WINDS INCREASING WITH A COLD ADVECTION  
REGIME TAKING HOLD.  
 
THURSDAY THROUGH FRIDAY...FORECAST CONFIDENCE IS MEDIUM.  
 
MODELS ARE SHOWING AN ELONGATED 500 MB SHORTWAVE TROUGH ROTATING  
SOUTHWARD THROUGH THE AREA THURSDAY, WITHIN CYCLONIC FLOW AROUND  
THE MAIN 500 MB LOW. FORECAST SOUNDINGS ARE INDICATING STEEP LOW  
LEVEL LAPSE RATES WITH SOME MOISTURE IN THE 700 MB TO 750 MB  
LAYER. THIS SHOULD ALLOW FOR CHANCES FOR RAIN AND SNOW SHOWERS,  
ESPECIALLY DURING THE AFTERNOON, WITH THERMAL PROFILES COLD ENOUGH  
FOR SOME SNOW SHOWERS AND/OR GRAUPEL TO OCCUR. ADDED SOME POPS TO  
THE FORECAST THURSDAY AFTERNOON.  
 
IN ADDITION, GUSTY NORTHWEST WINDS ARE EXPECTED TO CONTINUE  
THURSDAY INTO THURSDAY NIGHT, WITH THE HIGHEST GUSTS THURSDAY. GFS  
FORECAST SOUNDINGS ARE MORE AGGRESSIVE WITH GUSTS THAN THE NAM.  
GUSTS IN THE 30 TO 35 KNOT RANGE SEEM REASONABLE FOR MIDDAY  
THURSDAY ACROSS THE AREA, HIGHEST TOWARD THE LAKE. FOR NOW, IT  
DOES NOT SEEM LIKE 39 KNOT-PLUS GUSTS WOULD OCCUR. BELOW NORMAL  
TEMPERATURES ARE EXPECTED.  
 
NORTHWEST FLOW THEN HOLDS OVER THE REGION THURSDAY NIGHT INTO  
FRIDAY. HIGH PRESSURE PASSING TO THE SOUTH OF THE REGION FRIDAY  
SHOULD BRING QUIET WEATHER TO THE AREA. BELOW NORMAL TEMPERATURES  
ARE EXPECTED TO CONTINUE.  
 
LONG TERM...  
 
FRIDAY NIGHT THROUGH TUESDAY...FORECAST CONFIDENCE IS MEDIUM.  
 
GFS/ECMWF/CANADIAN MODELS CONTINUE TO DIFFER WITH THE TRACK AND  
STRENGTH OF LOW PRESSURE DURING THIS PERIOD. THEY GENERALLY SHOW  
LOW PRESSURE DEVELOPING OVER THE CENTRAL HIGH PLAINS FRIDAY NIGHT,  
THEN INTO THE SOUTHERN PLAINS BY SUNDAY, THEN NORTHEAST TOWARD THE  
GREAT LAKES REGION SUNDAY NIGHT AND MONDAY.  
 
THE GFS IS THE STRONGEST/MOST OCCLUDED AND FURTHEST TO THE NORTH  
SUNDAY NIGHT AND MONDAY, TAKING THE LOW NORTH ACROSS WISCONSIN  
INTO THE UPPER PENINSULA OF MICHIGAN. THERE COULD BE SOME LIGHT  
SNOW OR A MIX SUNDAY NIGHT INTO MONDAY, AS THE LOW MOVES THROUGH  
AND AWAY FROM THE AREA.  
 
THE ECMWF IS WEAKER AND TAKES MORE OF A TRACK INTO CENTRAL  
INDIANA AND LAKE ERIE SUNDAY NIGHT AND MONDAY. THE CANADIAN IS  
WEAKER STILL AND A LITTLE FURTHER EAST. THE GFS ENSEMBLES ARE FAR  
ENOUGH SOUTH OF THE REGION WITH THE LOW TRACK THAT SOUTHERN  
WISCONSIN WOULD NOT BE AFFECTED MUCH. HOWEVER, THE GEFS PLUMES  
WERE SHOWING DECENT QPF VALUES OF 0.50 TO 0.90 INCHES WITH THIS  
SYSTEM OVER PARTS OF THE AREA.  
 
FOR NOW, STILL ENOUGH UNCERTAINTY TO LEAVE THE BLENDED MODEL POPS  
AND TEMPERATURES ACROSS THE AREA FOR THE FRIDAY NIGHT INTO  
TUESDAY PERIOD. IT APPEARS TO BE WARM ENOUGH FOR RAIN ON MOST  
MODELS/ENSEMBLES INTO SUNDAY, BEFORE LIGHT SNOW/MIX POSSIBILITIES  
SUNDAY NIGHT INTO MONDAY MORNING. TEMPERATURES LOOK TO REMAIN A  
LITTLE BELOW SEASONAL NORMALS.  
 
AVIATION(09Z TAFS)...  
 
WILL HAVE A GOOD DEAL OF LIFR CONDITIONS THROUGH EARLY MORNING  
DUE TO DENSE FOG. EXPECTING IMPROVEMENT FROM MID MORNING ON, WITH  
CEILINGS TRANSITIONING TO MVFR AND PERHAPS VFR. RAIN CHANCES  
INCREASE INTO THE AFTERNOON AHEAD OF A FRONTAL BOUNDARY, SO A  
RETURN OF SOME MVFR CIGS/VSBYS. THIS FRONT GOES BY EARLY/MID  
AFTERNOON. ANY LINGERING RAIN CLEARS OUT IN THE EVENING.  
 
MARINE...  
 
MAIN STORY THIS MORNING IS DENSE FOG. PER COORDINATION WITH WFO  
CHICAGO SOUTHWARD PUSH OF STRATUS ON NIGHTTIME MICROPHYSICS LOOP  
HAVE PULLED THE OPEN WATERS MARINE DENSE FOG ADVISORY SOUTHWARD TO  
THE SOUTHERN EXTENT OF THE LAKE. ALSO ADDED THE NEARSHORE TO  
THIS. EXPECT SOME IMPROVEMENT AS THE MORNING WEARS ALONG.  
 
THEN ATTENTION TURNS TO POST-FRONTAL WIND REGIME LATER TODAY INTO  
THURSDAY. BEST SMALL CRAFT POTENTIAL WOULD BE LATER TONIGHT INTO  
THURSDAY, WHILE STILL SEEING EVIDENCE OF GALES FOR THE OPEN  
WATERS. SO, WILL HOLD OFF ON SMALL CRAFT ADVISORY ISSUANCE AT  
THIS TIME, BUT KEEP THE GALE WATCH GOING FOR THURSDAY INTO  
THURSDAY NIGHT.  
 

 
   
MKX WATCHES/WARNINGS/ADVISORIES
 
 
WI...DENSE FOG ADVISORY UNTIL 9 AM CDT THIS MORNING FOR WIZ046-047-  
051-052-056>060-062>072.  
 
LM...DENSE FOG ADVISORY UNTIL 10 AM CDT THIS MORNING FOR LMZ080-366-  
565-567-643>646-669-671-673-675-777-779-868-870-872-874-876-  
878.  
 
GALE WATCH FROM THURSDAY MORNING THROUGH FRIDAY MORNING FOR  
LMZ080-261-362-364-366-563-565-567-669-671-673-675-777-779-  
868-870-872-874-876-878.  
 

 
 

 
TODAY/TONIGHT AND AVIATION/MARINE...COLLAR  
THURSDAY THROUGH TUESDAY...WOOD  
 
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