904  
FXUS63 KGRR 190738  
AFDGRR  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE GRAND RAPIDS MI  
338 AM EDT TUE MAR 19 2024  
   
KEY MESSAGES
 
 
- SMALL CHANCES OF SNOW NORTH TODAY AND WEDNESDAY  
 
- MEDIUM TO HIGH CONFIDENCE FOR SNOW/MIX LATE WEEK  
 
- LOW CONFIDENCE ON STORMINESS EARLY NEXT WEEK  
 

 
   
DISCUSSION
 
 
ISSUED AT 338 AM EDT TUE MAR 19 2024  
 
- SMALL CHANCES OF SNOW NORTH TODAY AND WEDNESDAY  
 
THE COUPLE OF CHANCES OF SNOW UP NORTH THAT WE WILL SEE TODAY, AND  
THEN AGAIN WEDNESDAY, WILL BE ASSOCIATED WITH A COUPLE OF DIFFERENT  
SHORT WAVES BRUSHING THE AREA. THE CIRCUMSTANCES WILL BE FAR FROM  
IDEAL WITH EACH OF THE WAVES TO BRING MUCH MORE THAN A COUPLE OF  
TENTHS OF AN INCH ACROSS THE NORTH.  
 
THE FIRST WAVE APPROACHING THE AREA TODAY IS COMING IN FROM THE WNW.  
THE FIRST THING GOING AGAINST MUCH PRECIPITATION FROM THIS WAVE IS  
IT IS EXPECTED TO SHEAR OUT AS IT DROPS THROUGH THE AREA TODAY. IN  
ADDITION, DEEP MOISTURE IS NEVER REALLY IN PLACE. WE INITIALLY HAD  
SOME LOW LEVEL MOISTURE THAT IS MAKING ITS WAY OUT CURRENTLY. BY THE  
TIME THE MID/UPPER LEVEL MOISTURE LOWERS ENOUGH, THERE IS NO LOW  
LEVEL MOISTURE TO HELP IT REACH THE GROUND. THE BEST CHANCE WHERE  
THESE LAYERS OF MOISTURE WILL OVERLAP ENOUGH TO GET SOME SNOW AT THE  
SFC WILL BE ACROSS THE U.S.-10 CORRIDOR THIS MORNING.  
 
THE SNOW CHANCES THEN END THIS AFTERNOON AS THE WAVE AND MOISTURE  
MOVES BY, LEAVING SOME SHORT WAVE RIDGING IN PLACE. THEN LATER  
TONIGHT INTO WEDNESDAY, WE WILL SEE THE NEXT SHORT WAVE APPROACH THE  
AREA FROM THE NW. THIS WAVE WILL REMAIN INTACT AND EVEN STRENGTHEN A  
BIT AS IT APPROACHES. THE PROBLEM WITH THIS WAVE FOR PRECIPITATION  
CHANCES IS THAT THE TRACK OF IT JUST BARELY BRUSHES OUR NORTHERN  
COUNTIES AGAIN. MOISTURE IS ONCE AGAIN LIMITED FOR MOST OF THE AREA,  
WITH JUST A THIN LAYER UP AROUND 4-5K FT, AND NO REAL DEPTH IN OUR  
AREA.  
 
- MEDIUM TO HIGH CONFIDENCE FOR SNOW/MIX LATE WEEK  
 
UPPER TROUGHING WILL EXTEND SOUTH INTO THE GREAT LAKES FROM THE  
POLAR VORTEX ACROSS HUDSON BAY BY THURSDAY. AN AREA OF SNOW BLOSSOMS  
IN A BAROCLINIC ZONE ACROSS THE NW CONUS/SW CANADA ON WEDNESDAY AND  
MOVES SOUTHEAST ALONG THE ARCTIC FRONT, ARRIVING IN LOWER MICHIGAN  
BY LATE THURSDAY NIGHT INTO FRIDAY. MODELS ARE CONVERGING ON THE  
EVOLUTION OF A SFC WAVE FORMING ALONG THE FRONT, LEADING TO HIGHER  
CONFIDENCE IN THE CHANCES FOR SOME MEASURABLE SNOW. THE SURFACE LOW  
IS PROGGED TO SHEAR OUT AND WEAKEN, BECOMING AN OPEN WAVE BY FRIDAY  
WITH SNOW AND MIXED PRECIP DIMINISHING, BUT IT APPEARS THAT THE  
TIMING OF THE SNOW WILL IMPACT TRAVEL FOR THE MORNING COMMUTE.  
 
- LOW CONFIDENCE ON STORMINESS EARLY NEXT WEEK  
 
WESTERN CONUS TROUGHING AMPLIFIES AND GOES NEGATIVE TILT EARLY NEXT  
WEEK AND A SURFACE CYCLONE WILL EVOLVE OVER THE PLAINS. ENSEMBLE  
SPREAD IS SIGNIFICANT ON THE DETAILS OF HOW THIS EVOLVES. THE  
CURRENT FORECAST IS MOST REFLECTIVE OF THE GFS WITH A LESS HIGHLY  
AMPLIFIED SOLUTION AND SNOW ARRIVING ON SUNDAY, CHANGING TO RAIN ON  
MONDAY. THE MORE AMPLIFIED, BLOCKY SOLUTIONS OF THE ECMWF AND GEM  
WOULD HOLD OFF PRECIP UNTIL MONDAY OR TUESDAY.  
 

 
   
AVIATION /06Z TAFS THROUGH 06Z WEDNESDAY/
 
 
ISSUED AT 147 AM EDT TUE MAR 19 2024  
 
VFR CONDITIONS WILL CONTINUE THROUGH WEDNESDAY EVENING. STRATUS  
DECK WILL PREVAIL WITH BASES AROUND 3500 TO 5000 FEET AGL THIS  
MORNING. WEST WINDS WILL GUST OVER 20 KTS THIS MORNING THEN GO  
NORTHWEST IN THE AFTERNOON.  
 

 
   
MARINE
 
 
ISSUED AT 338 AM EDT TUE MAR 19 2024  
 
WE WILL BE HOLDING ON TO THE SMALL CRAFT ADVISORY, AND EXTENDING IT  
YET AGAIN THROUGH WEDNESDAY NIGHT.  
 
WE DID GIVE SOME CONSIDERATION TO UPGRADING TO A GALE FOR TODAY, BUT  
ULTIMATELY DECIDED THAT THE IT IS A MARGINAL SITUATION FOR TOO SHORT  
OF A DURATION.  
 
WINDS WILL DIMINISH SLIGHTLY TONIGHT AS ONE CORE OF WIND MOVES OUT,  
AND THEN ANOTHER WILL MOVE IN ON WEDNESDAY. WE COULD BE FLIRTING  
WITH GALES ONCE AGAIN, BUT THE SITUATION LOOKS EVEN LESS FAVORABLE  
THAN THE MARGINAL SCENARIO TODAY. WINDS WILL FINALLY DIMINISH  
WEDNESDAY NIGHT, WITH WAVES FALLING BELOW CRITERIA BY THURSDAY AT  
12Z.  
 

 
   
GRR WATCHES/WARNINGS/ADVISORIES
 
 
MI...NONE.  
MARINE...SMALL CRAFT ADVISORY UNTIL 8 AM EDT THURSDAY FOR LMZ844>849.  
 

 
 

 
 
DISCUSSION...NJJ/OSTUNO  
AVIATION...OSTUNO  
MARINE...NJJ  
 
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