567  
FXUS63 KGRR 190247  
AFDGRR  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE GRAND RAPIDS MI  
947 PM EST FRI JAN 18 2019  
 
LATEST UPDATE...  
UPDATE  
   
SYNOPSIS
 
 
ISSUED AT 256 PM EST FRI JAN 18 2019  
 
- SNOW TONIGHT AND SATURDAY  
 
- SUBZERO WIND CHILLS SATURDAY NIGHT AND SUNDAY  
 
- LOWS MONDAY MORNING 0 TO 10 BELOW  
 
- SNOWSTORM/MIXED PRECIP TUESDAY INTO WEDNESDAY  
 

 
   
UPDATE
 
 
ISSUED AT 948 PM EST FRI JAN 18 2019  
 
NO CHANGES TO THE CURRENT FORECAST.  
 
THE CURRENT SNOW EVENT IS JUST GETTING UNDERWAY. THE ATMOSPHERE IS  
SLOWLY SATURATING AND WE'RE SEEING THE DONUT HOLE ON THE RADAR  
SLOWLY FILL IN. SNOW IS BEING OBSERVED ALONG I-94 AND THAT WILL  
MOVE NORTH OVERNIGHT. LOOK FOR 1-3 INCHES OVERNIGHT ALONG I-96  
AND 2-4 INCHES ALONG I-94 ALONG WITH ANOTHER INCH OR TWO SATURDAY.  
 

 
   
DISCUSSION
 
(THIS EVENING THROUGH NEXT FRIDAY)  
ISSUED AT 256 PM EST FRI JAN 18 2019  
 
BANDS OF SNOW IN AREA OF STRONG MID-LEVEL F-GEN ARE TRANSLATING  
EAST FROM SOUTHERN MINNESOTA AND WISCONSIN THIS AFTERNOON AND WILL  
ARRIVE IN OUR SOUTHWEST ZONES THIS EVENING. STILL EXPECT 1 TO 3  
INCHES ACROSS I-96 CORRIDOR AND 3 TO 5 INCHES ACROSS I-94 BY THE  
TIME THE SNOW ENDS SATURDAY AFTERNOON. THE HRRR AND ARW SHOW THE  
POTENTIAL FOR THE HEAVIEST BAND, ORIENTED EAST-WEST, TO BE  
CENTERED IN BETWEEN I-96 AND I-94. AMOUNTS IN THIS AREA THAT  
REMAIN UNDER THE BAND THE LONGEST COULD SEE 6 PLUS INCHES STORM  
TOTALS.  
 
THE NEXT ISSUE IS THE COLD FOLLOWING THE STORM. THE APPARENT  
TEMPERATURE, COMBINING WINDS AND AIR TEMPERATURES, FALL BELOW ZERO  
SATURDAY NIGHT AND REMAIN THERE THROUGH MONDAY MORNING. ACTUAL  
TEMPERATURES WILL BE NEAR ZERO SUNDAY MORNING, ONLY RISING TO THE  
MID TEENS SUNDAY THEN, WITH SFC RIDGING AND CLEAR SKIES, PLUMMET  
SUNDAY NIGHT TO AS COLD AS 10 BELOW BY MONDAY MORNING.  
 
ANOTHER STORM ARRIVES TUESDAY AND MODEL SPREAD CONTINUES TO BE  
SIGNIFICANT, LIMITING FORECAST CONFIDENCE. THE POTENTIAL IS STILL  
THERE FOR HEAVY SNOW, ALONG WITH A MIX TO SLEET AND RAIN ACROSS  
THE SOUTHERN HALF OF THE FORECAST AREA. STAY TUNED FOR UPDATE SON  
THIS STORM.  
 

 
   
AVIATION
 
(FOR THE 00Z TAFS THROUGH 00Z SATURDAY EVENING)  
ISSUED AT 649 PM EST FRI JAN 18 2019  
 
SNOW WILL BE WORKING IN FROM THE WEST LEADING TO IMPACTS AT THE  
TAF SITES. THE LOWEST CEILINGS AND VISIBILITIES LOOK TO BE FROM  
KAZO TO KBTL TO KJXN. WE WILL NEED TO MONITOR THE TRACK OF THIS  
HEAVIER SNOW BAND AS THERE IS SOME POTENTIAL FOR IT TO BE LOCATED  
FURTHER NORTH. THE SNOW WILL MOVE IN EARLY THIS EVENING...BUT WILL  
NOT PULL AWAY TIL LATER IN THE MORNING OR EARLY AFTERNOON. GUSTY  
WINDS OVER 20 KNOTS WILL OCCUR ESPECIALLY LATER TONIGHT INTO  
SATURDAY. IMPROVING CEILINGS AND VISIBILITIES ARE FORECASTED FOR  
SATURDAY AFTERNOON.  
 

 
   
MARINE
 
 
ISSUED AT 256 PM EST FRI JAN 18 2019  
 
OFFSHORE WINDS WILL INCREASE TONIGHT INTO SATURDAY. A SMALL CRAFT  
ADVISORY MAY BE NEEDED FOR SATURDAY AFTERNOON INTO SUNDAY.  
FREEZING SPRAY IS EXPECTED SATURDAY NIGHT THROUGH SUNDAY AS VERY  
COLD AIR MOVES ACROSS THE LAKE AND A RAPID BUILDUP OF LAKE ICE  
ALONG THE SHORE CAN BE EXPECTED ON SUNDAY AND MONDAY.  
 

 
   
HYDROLOGY
 
 
ISSUED AT 256 PM EST FRI JAN 18 2019  
 
WATER LEVELS HAVE DROPPED TO NEAR OR EVEN SLIGHTLY BELOW THE NORMAL  
VALUES FOR THIS TIME OF YEAR. MUCH COLDER TEMPERATURES EXPECTED OVER  
THE WEEKEND AND EARLY NEXT WEEK WILL CAUSE SIGNIFICANT ICE GROWTH ON  
OUR RIVERS. SNOWFALL TONIGHT AND SATURDAY WILL INCREASE THE RATE OF  
NEW ICE GROWTH. BY THE END OF NEXT WEEK, MANY OF OUR STREAMS WILL  
PROBABLY HAVE A SOLID COVER OF ICE. BETWEEN NOW AND THEN WILL BE OUR  
MOST VULNERABLE WINDOW FOR ICE JAMS TO FORM. LOCATIONS PRONE TO ICE  
JAM FLOODING SHOULD PAY EXTRA ATTENTION TO THE RIVERS AND PREPARE  
NOW FOR POSSIBLE FAST CHANGES IN WATER LEVELS.  
 

 
   
GRR WATCHES/WARNINGS/ADVISORIES
 
 
MI...WINTER WEATHER ADVISORY UNTIL 4 PM EST SATURDAY FOR MIZ056>059-  
064>067-071>074.  
 
LM...NONE.  

 
 

 
 
UPDATE...04  
SYNOPSIS...OSTUNO  
DISCUSSION...OSTUNO  
AVIATION...MJS  
HYDROLOGY...AMD  
MARINE...OSTUNO  
 
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