108
FXUS63 KGRR 201932
AFDGRR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND RAPIDS MI
232 PM EST FRI DEC 20 2024
KEY MESSAGES
- A FEW LIGHT LAKE EFFECT SNOW BANDS INTO SATURDAY
- PRECIPITATION EXPECTED FOR MONDAY INTO MONDAY NIGHT
- MODERATING TEMPERATURES FOR THE MID TO END OF NEXT WEEK
DISCUSSION
ISSUED AT 155 PM EST FRI DEC 20 2024
- A FEW LIGHT LAKE EFFECT SNOW BANDS INTO SATURDAY
A NORTHEAST FLOW BACKS TO THE NORTH THIS EVENING, RESULTING IN
STRENGTHENING COLD AIR ADVECTION. ALREADY SEVERAL BANDS OF LIGHT
SNOW HAVE BEEN TRACKING SOUTHWESTWARD THROUGH OUR CWA. MOST
LOCATIONS WILL SEE UP TO A DUSTING OF SNOW FROM THE SNOW
SHOWERS/FLURRIES. THE MOISTURE TONIGHT IS NOT FORECAST TO BE VERY
DEEP, REMAINING UNDER 5K FT WITH THE DGZ ABOVE THE MOISTURE.
UNLESS THAT CHANGES, ANY SNOWFALL THAT WE SEE SHOULD REMAIN VERY
LIGHT/FLURRIES. FOR NOW WE WILL KEEP POPS MOSTLY IN THE LOW CHANCE
RANGE FOR FAVORED AREAS TO SEE ANY SNOW SHOWERS. WITH NORTHERLY
FLOW, THIS TYPICALLY FAVORS THE LAKESHORE COUNTIES FOR INCREASED
LOW LEVEL CONVERGENCE.
- PRECIPITATION EXPECTED FOR MONDAY INTO MONDAY NIGHT
WARM AND MOIST AIR ADVECTION STRENGTHENS MONDAY INTO MONDAY NIGHT.
THE MOISTURE DEEPENS UP AS A WAVE OF LOW PRESSURE TRACKS
NORTHEASTWARD THROUGH THE NORTHWEST GREAT LAKES REGION DURING THIS
TIME. FROM A DGZ SATURATION PERSPECTIVE, THIS SYSTEM LOOKS
DISORGANIZED OVER OUR CWA. THE LOW AND MID LEVEL MOISTURE NEVER
REALLY LINE UP WHICH COMMONLY LEADS TO RATHER LIGHT AMOUNTS OF
QPF. WE DON'T RISE ABOVE FREEZING ON MONDAY UNTIL THE AFTERNOON,
SO IF ANY OF THE PRECIPITATION ENDS UP BEING LIQUID(UNSATURATED
DGZ) THEN A RISK FOR A SHORT PERIOD OF FREEZING RAIN COULD OCCUR.
- MODERATING TEMPERATURES FOR THE MID TO END OF NEXT WEEK
BASED ON THE TRACK OF THE MONDAY-TUESDAY SYSTEM, ANY COLD AIR
ADVECTION ON THE BACKSIDE OF IT WILL BE WEAK AND NOT VERY DEEP.
WARM AIR ADVECTION RETURNS WEDNESDAY AND MORE SO THURSDAY. TEMPS
AT 850 MB CLIMB TO 5 OR 6 DEG C, BUT ITS SHOWN TO BE MOIST AT
THAT LEVEL. THE 925 MB TEMPS ARE A LITTLE LOWER, SO ITS SOMEWHAT
OF A STABLE MIXING SITUATION. WE WILL FEATURE ABOVE NORMAL
TEMPERATURES WITH VALUES REACH THE 40'S BY THE END OF THE WEEK,
WHICH IS IN LINE WITH THE ENSEMBLE VALUES.
AVIATION /18Z TAFS THROUGH 18Z SATURDAY/
ISSUED AT 1231 PM EST FRI DEC 20 2024
MOISTURE STREAMING IN OFF OF LAKE HURON WILL CONTINUE TO KEEP THE
CEILINGS LOWER ESPECIALLY FOR THE REGION EAST OF KGRR INTO MID
AFTERNOON, THEN THE NORTHERLY FLOW WILL SHIFT THAT MOISTURE TO THE
SOUTHEAST OF KJXN. THERE WILL BE SOME SNOW SHOWER ACTIVITY WITHIN
THE CLOUDS, MAINLY THROUGH MID AFTERNOON. SOME CLEARING IS
PREDICTED FOR THE EVENING AND INTO TONIGHT AS SUBSIDENCE PREVAILS.
WE WILL FEATURE A TREND TOWARD VFR FOR MOST LOCATIONS AS A RESULT.
GRR WATCHES/WARNINGS/ADVISORIES
MI...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 10 AM EST SATURDAY FOR LMZ844-845-848-
849.
DISCUSSION...MJS
AVIATION...MJS
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