821  
FXUS63 KGRB 232002  
AFDGRB  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE GREEN BAY WI  
202 PM CST SUN FEB 23 2020  
 
FORECAST DISCUSSION FOR ROUTINE AFTERNOON FORECAST ISSUANCE  
   
SHORT TERM
 
TONIGHT AND MONDAY  
ISSUED AT 201 PM CST SUN FEB 23 2020  
 
EARLY THIS AFTERNOON, A SURFACE COLD FRONT CONTINUED TO TRACK  
ACROSS THE STATE. THE FRONT WASN'T AMOUNTING TO MUCH OTHER THAN  
WINDS VEERING MORE WESTERLY AND CREATING SOME GUSTS TO 20 TO 30  
KNOTS. THE COMBINATION OF SUNNY SKIES AND WAA BROUGHT TEMPERATURES  
WELL INTO THE 40S, WITH READINGS AT 2 PM RANGING FROM THE MIDDLE  
40S TO LOW 50S.  
 
CHALLENGE IN THE SHORT TERM IS CLOUD AND TEMPERATURE TRENDS. SOME  
OF THE SHORT-TERM GUIDANCE MAY BE OVERDOING THE LOW LEVEL  
MOISTURE, THEREFORE USED A BLEND OF THE GFS, EC, CANADIAN AND ADJ  
GUIDANCE WHICH SEEMED TO HAVE A BETTER HANDLE ON THE CURRENT  
SITUATION. SOME HIGH CLOUDS MAY MAKE IT INTO THE AREA TONIGHT, BUT  
CONFIDENCE IS LOW. CONFIDENCE IS ALSO LOW ON THE POTENTIAL FOR ANY  
LOW CLOUDS TO DEVELOP ACROSS THE NORTH. STRATUS DEVELOPMENT LAST  
NIGHT WAS RELATIVELY SHORT-LIVED, BUT THERE COULD BE ENOUGH  
BOUNDARY LAYER MOISTURE/WINDS TO GENERATE SOME LOW CLOUDS  
TONIGHT. WENT WITH A PARTLY CLOUDY SOLUTION ACROSS CENTRAL AND  
NORTH- CENTRAL WI. LOWS TONIGHT WILL BE IN THE UPPER TEENS TO  
MIDDLE 20S.  
 
FOR MONDAY, WINDS WILL VEER NORTHEAST WHICH SHOULD ALLOW FOR  
COOLER AIR TO FILTER INTO THE AREA, ALONG WITH INCREASING CLOUDS  
DURING THE AFTERNOON. HIGHS WILL BE IN THE MID TO UPPER 30S.  
   
LONG TERM
 
MONDAY NIGHT THROUGH SUNDAY  
ISSUED AT 201 PM CST SUN FEB 23 2020  
 
MAIN CONCERN IN THE EXTENDED FORECAST WILL BE THE POTENTIAL FOR A  
WINTER STORM SYSTEM TO IMPACT PORTIONS OF THE AREA BY MID-WEEK.  
THERE HAS BEEN A CONTINUED SOUTHEASTWARD TREND WITH THIS SYSTEM.  
 
MONDAY NIGHT INTO TUESDAY: LOW PRESSURE ACROSS THE MID-MISSISSIPPI  
VALLEY IS EXPECTED TO LIFT EAST-NORTHEASTWARD TOWARD THE OHIO RIVER  
VALLEY THROUGH THIS TIME PERIOD. ALOFT, AN INTENSIFYING VORT  
MAX/CLOSED 500MB LOW IS EXPECTED TO SLIDE ACROSS THE CENTRAL PLAINS  
INTO THE MID-MISSISSIPPI VALLEY. THE BETTER UPPER-LEVEL JET ENERGY  
(LEFT-EXIT REGION) IS EXPECTED TO REMAIN WELL SOUTHEAST OF THE AREA  
THROUGH THIS TIME PERIOD. THE BETTER SYSTEM DYNAMICS REMAINING  
SOUTHEAST OF THE AREA ALONG WITH FAIRLY DRY AIR ON THE NORTHERN  
FRINGES OF THE SURFACE AND 850MB LOW, WILL KEEP CONDITIONS MAINLY  
DRY ACROSS NORTHEAST WISCONSIN THROUGH THIS TIME PERIOD. LOWS ARE  
EXPECTED TO BE IN THE 20S WITH HIGHS EXPECTED TO BE IN THE 30S  
ACROSS MUCH OF THE AREA.  
 
TUESDAY NIGHT THROUGH WEDNESDAY NIGHT: MODELS ARE STILL STRUGGLING  
TO SETTLE ON EXACTLY HOW FAR NORTH OR SOUTH THE HEAVIEST BAND OF  
SNOW WILL SET UP ACROSS THE AREA. THIS SYSTEM IS JUST BEGINNING TO  
BE SAMPLED BETTER AS IT IS PUSHING INTO THE NORTHWEST CONUS TODAY,  
WHICH SHOULD BEGIN TO INCREASE CONFIDENCE IN THE SYSTEM OVER THE  
NEXT 24 HOURS. THERE HAS BEEN A CONTINUED TREND TO SHIFT THE HEAVIER  
SNOW BAND TO THE SOUTHEAST. THIS IS LARGELY A RESULT OF THE BOTH THE  
SURFACE LOW AND 850MB LOW SHIFTING A BIT FARTHER SOUTHEAST. EVEN THE  
GFS (OUTLIER) HAS TRENDED THAT DIRECTION. THE ONE THING THAT MODELS  
ARE IN GOOD AGREEMENT ABOUT IS THAT THE PRECIPITATION SHOULD BE  
MAINLY IN THE FORM OF SNOW WHERE ANY PRECIPITATION FALLS. THE GFS IS  
STILL THE FARTHEST NORTHWEST (BRINGING THE HEAVIEST SNOW TO EAST-  
CENTRAL/FAR NORTHEAST WI), WHILE THE 12Z CANADIAN/EC IS FARTHEST  
SOUTHEAST, BRINGING LITTLE TO NO SNOW FOR MOST OF NORTHEAST WI. THE  
NAM IS MORE IN THE MIDDLE OF THE PACK BRINGING A HEAVIER BAND OF  
SNOW TO LOCATIONS SOUTHEAST OF A LINE FROM ROUGHLY DOOR COUNTY TO  
GREEN BAY TO APPLETON. THE HEAVIEST SNOW WOULD LIKELY OCCUR NEAR  
MANITOWOC IN ANY OF THE AFOREMENTIONED SCENARIOS. SOME LAKE  
ENHANCEMENT MAY ALSO OCCUR, BUT TEMPERATURES SEEM MARGINAL FOR THAT  
AT THIS POINT AND WILL BE LARGELY RELIANT UPON SURFACE TO 850MB WIND  
DIRECTION. MODEL PLUMES GENERALLY PAINT OUT MEAN VALUES AROUND 1 TO  
2 INCHES FROM THE DOOR PENINSULA SOUTHWEST TO GREEN BAY AND  
APPLETON, WITH A QUICK CUTOFF TO THE NORTHWEST OF THAT LINE. CLOSER  
TO THE SHORELINE, NEAR MANITOWOC, MODEL PLUMES ARE CLOSER TO MEAN  
VALUES OF 3 TO 6 INCHES. THE MODEL SPREAD IS VERY SIGNIFICANT, SO  
THOSE ARE VERY PRELIMINARY NUMBERS WITH FAIRLY LOW CONFIDENCE.  
AGAIN, THE CONFIDENCE IN THE RANGE OF VALUES IS LOW ENOUGH AT THIS  
POINT TO KEEP FROM ISSUING ANY TYPE OF WINTER HEADLINES, BUT THEY  
MAY BE NEEDED OVER THE NEXT COUPLE OF DAYS.  
 
REST OF THE EXTENDED: SOME WRAP-AROUND MOISTURE MAY LINGER ACROSS  
THE AREA THROUGH THE DAY THURSDAY AS ADDITIONAL SHORTWAVE ENERGY  
PASSES THROUGH THE AREA. THIS MAY LEAD TO SOME LIGHT SNOW SHOWERS OR  
FLURRIES ACROSS THE AREA ALONG WITH SOME LIGHT LAKE EFFECT SNOW  
ACROSS NORTH-CENTRAL PORTIONS OF THE AREA. OTHERWISE, FAIRLY QUIET  
WEATHER IS EXPECTED INTO NEXT WEEKEND AS HIGH PRESSURE AND RISING  
500MB HEIGHTS BEGIN TO BUILD INTO MUCH OF WI. THIS WOULD LEND  
SUPPORT FOR A WARMING TREND TOWARD NEXT WEEKEND INTO EARLY IN THE  
NEXT WEEK.  

 
   
AVIATION
 
FOR 18Z TAF ISSUANCE  
ISSUED AT 1119 AM CST SUN FEB 23 2020  
 
PRIMARILY VFR FLIGHT CONDITIONS THROUGH 18Z MONDAY WITH PERIODS  
OF LLWS. CLEAR SKIES WERE NOTED ACROSS THE AREA LATE SUNDAY  
MORNING, WHICH IS EXPECTED TO CONTINUE UNTIL AT LEAST EARLY THIS  
EVENING. MODELS ARE STRUGGLING TO HANDLE THE POTENTIAL FOR CLOUD  
DEVELOPMENT TONIGHT. OPTED TO BRING IN SCATTERED HIGH CLOUDS  
ACROSS ALL TAF SITES, AND SOME LOWER STRATUS AT KRHI AFTER  
MIDNIGHT. WOULD NOT BE SURPRISED IF THERE WERE A COUPLE HOURS OF  
LOWER CLOUDS AT THE KAUW AND KCWA SITES LATE TONIGHT, BUT  
CONFIDENCE IS LOW. MEANWHILE, MODERATE SW WIND GUSTS AND LLWS  
AROUND 1000 TO 1500 FEET WILL PERSIST THROUGH THE EVENING.  

 
   
GRB WATCHES/WARNINGS/ADVISORIES
 
 
NONE.  

 
 

 
 
SHORT TERM.....KLJ  
LONG TERM......COOLEY  
AVIATION.......KLJ  
 
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