046
FXUS63 KGRR 170541
AFDGRR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND RAPIDS MI
1241 AM EST TUE DEC 17 2024
KEY MESSAGES
- SNOW SHOWERS POSSIBLE LATER TUESDAY NIGHT/WEDNESDAY MORNING
- MINOR SNOW ACCUMULATIONS LATER THURSDAY INTO FRIDAY
- COLD WEEKEND
UPDATE
ISSUED AT 932 PM EST MON DEC 16 2024
DEEP LOW PRESSURE IS CENTERED OVER NORTHERN ONTARIO THIS EVENING
NORTH OF LAKE SUPERIOR. HIGH PRESSURE IS ALIGNED NORTH/SOUTH IN
THE PLAINS. IN BETWEEN, BRISK WESTERLY WINDS (10-20 MPH WITH GUSTS
TO 30+) ARE OCCURRING ACROSS THE GREAT LAKES REGION. THIS WILL
LARGELY REMAIN THE CASE THROUGH THE REMAINDER OF THE NIGHT. LOW
TEMPERATURES WILL BOTTOM OUT IN THE LOWER TO MIDDLE 30S TONIGHT.
CLOUDS WILL LIKELY HANG ON IN MOST AREAS DESPITE A CLEARING TREND
THAT IS OCCURRING UPSTREAM. DELTA T'S OVER LAKE MICHIGAN WILL
INCREASE ENOUGH TO BEGIN THE GENERATION OF LAKE STRATOCUMULUS.
CANNOT RULE OUT SOME BREAKS ACROSS THE FAR SOUTH HOWEVER TOWARDS
I-94. AN ISOLATED SHOWER OR TWO IS POSSIBLE FOR THE NEXT FEW
HOURS, BUT AS CYCLONIC CURVATURE ALOFT PULLS AWAY TO THE
NORTHEAST OVERNIGHT, SO WILL ANY PRECIPITATION CHANCES.
DISCUSSION
ISSUED AT 152 PM EST MON DEC 16 2024
- SNOW SHOWERS POSSIBLE LATER TUESDAY NIGHT/WEDNESDAY MORNING
A WEAK WAVE OF LOW PRESSURE TRACKS UP THE OH VALLEY DURING THIS
TIMEFRAME. COLDER AIR WILL BE FILTERING IN FROM THE NORTHEAST HERE
IN MI SO WE ARE EXPECTING ANY OF THE PRECIPITATION THAT FALLS FROM
THIS SYSTEM TO BE MAINLY IN THE FORM OF SNOW. THIS SYSTEM IS SHOWN
TO BE FAIRLY DISORGANIZED AS IT TRACKS INTO THE AREA BUT IT MAY
INCREASE IN STRENGTH AS IT MOVES AWAY. THE DGZ DOES MOISTEN UP AND
THERE IS SOME LIFT IN THAT ZONE SO WE WILL NEED TO MONITOR IT
CLOSELY. THE WEDNESDAY MORNING COMMUTE LOOKS TO BE ABOUT WHEN THE
BEST CHANCE FOR SNOW SHOWERS WILL BE SO, A RISK FOR SOME SLICK
SPOTS ON THE ROADWAYS EXISTS. ENSEMBLE SNOW AMOUNTS HAVE BEEN
HOLDING FAIRLY STEADY IN FAVORING MOST AREAS TO SEE LESS THAN AN
INCH FROM THIS RELATIVELY WEAK SYSTEM.
- MINOR SNOW ACCUMULATIONS LATER THURSDAY INTO FRIDAY
THIS NEXT CLIPPER SYSTEM WILL BE DIGGING INTO THE REGION LATER
THURSDAY AND INTO THURSDAY NIGHT. THE DURATION OF DEEPER MOISTURE
AND LIFT WILL BE GREATER SO WE ARE LIKELY TO SEE MORE IMPACTS.
THIS SYSTEM COULD CATCH PART OF THE THURSDAY EVENING AND FRIDAY
MORNING COMMUTES. ENSEMBLE MEAN ACCUMULATIONS ARE GENERALLY 1 TO
3 INCHES BUT THERE IS STILL A FAIR AMOUNT OF SPREAD AMONGST THE
MEMBERS.
- COLD WEEKEND
ARCTIC HIGH PRESSURE BUILDS INTO THE NORTHERN GREAT LAKES REGION
TO START THE WEEKEND. HERE IN LOWER MI WE WILL SEE AN EASTERLY
COMPONENT TO THE WINDS. THIS WILL ACT TO PUSH MOST OF THE LAKE
EFFECT SNOW AWAY FROM OUR CWA. TEMPS AT 925 MB FALL STEADILY INTO
SUNDAY MORNING. THE GFS SHOWS A 925 MB THERMAL TROUGH OF -10 DEG
C OVER GRR AT 12Z SUNDAY. WITH THE POSSIBILITY FOR FRESH SNOW AND
RELATIVELY CLEAR SKIES, WE WILL LIKELY END UP WITH A VERY COLD
NIGHT SATURDAY NIGHT. ENSEMBLE TEMPERATURE GUIDANCE HAS GENERALLY
BEEN TRENDING DOWNWARD FOR SATURDAY NIGHTS VALUES. WE WILL FEATURE
SINGLE DIGITS FOR MOST OF THE CWA.
AVIATION /06Z TAFS THROUGH 06Z WEDNESDAY/
ISSUED AT 1228 AM EST TUE DEC 17 2024
GUSTY WESTERLY WINDS AROUND 25 KNOTS CONTINUE INTO TUESDAY
MORNING. MVFR CEILINGS MAINLY AROUND 2000 FEET ARE ALSO EXPECTED
TO LINGER THROUGH MOST OF THE DAY BEFORE LIFTING BRIEFLY TO VFR
VALUES LATE TUESDAY NIGHT BEFORE OUR NEXT ROUND OF SNOW MOVES IN.
GRR WATCHES/WARNINGS/ADVISORIES
MI...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 7 PM EST THIS EVENING FOR LMZ844>849.
UPDATE...DUKE
DISCUSSION...MJS
AVIATION...RAH
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