659
FXUS63 KGRR 060839
AFDGRR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND RAPIDS MI
339 AM EST TUE JAN 6 2026
KEY MESSAGES
- MIXTURE OF PRECIPITATION EXPECTED TODAY
- WARMER WITH RAIN THURSDAY AND FRIDAY
- COLDER WITH CHANCES FOR SNOW THIS WEEKEND
DISCUSSION
ISSUED AT 339 AM EST TUE JAN 6 2026
- MIXTURE OF PRECIPITATION EXPECTED TODAY
A MID LEVEL SHORTWAVE CAN BE SEEN IN WATER VAPOR IMAGERY ZIPPING
EAST ACROSS IOWA EARLY THIS MORNING. THIS WAVE WILL BE THE DRIVER
FOR MIXED PRECIPITATION ACROSS SOUTHWEST LOWER MICHIGAN TODAY.
SURFACE LOW PRESSURE HAS FORMED AND IS SITUATED NEAR THE
IOWA/ILLINOIS BORDER AS OF 08Z. THE MID LEVEL WAVE AND ITS
SURFACE LOW WILL MOVE THROUGH THE FORECAST AREA TODAY, WITH THE
SURFACE LOW SLIDING EAST ACROSS SOUTHERN LOWER MICHIGAN NEAR
I-94. PRECIPITATION WILL BE DRIVEN BY THE LEFT EXIT REGION OF A
140 KNOT UPPER JET THAT WILL RESULT IN A WARM AIR ADVECTION
RESPONSE IN LOW LEVELS. THE RESULTANT ISENTROPIC LIFT IS QUITE
STRONG THIS MORNING WHICH WILL BE FOCUSED BY A WARM FRONT.
SURFACE TEMPERATURES WILL BE A FEW DEGREES EITHER SIDE OF THE
FREEZING MARK THIS MORNING AS THE PRECIPITATION DEVELOPS. WE ARE
EXPECTING RAIN IN THE SOUTH NEAR I-94 FOR THE MOST PART. A BRIEF
MIX CAN BE EXPECTED NEAR I-96 BUT IMPACTS WILL BE LIMITED AS
TEMPERATURES WARM TO ABOVE FREEZING AROUND OR SHORTLY AFTER
DAYBREAK. THE WINTER WEATHER ADVISORY LOOK IN GREAT SHAPE (NO
CHANGES WITH THIS FORECAST) AS THIS IS WHERE THE TEMPERATURES ARE
EXPECTED TO BE SLIGHTLY BELOW FREEZING (32F) AT THE ONSET OF
PRECIP (ROUGHLY NORTH OF A PENTWATER TO NEWAYGO TO HOWARD CITY TO
ALMA LINE). THE BELOW 32F AIR QUICKLY CONTRACTS FURTHER THIS
MORNING TO OUR NORTHEAST COUNTIES, WHICH IS THE CLIMATOLOGICAL
LOCATIONS THAT SEE FREEZING PRECIPITATION THE LONGEST GIVEN ITS
OUR FURTHEST NORTH AREA AND HIGHEST GROUND/ELEVATION. THE AREA TO
SEE FREEZING PRECIPITATION THE LONGEST WILL BE ACROSS OSCEOLA,
CLARE, MECOSTA AND ISABELLA COUNTIES. SO, THE BOTTOM LINE IS RAIN
WILL SPREAD INTO AREAS IN THE SOUTH EARLY THIS MORNING IT WILL BE
A MIX NORTH OF I-96 WHERE SNOW AND FREEZING RAIN ARE EXPECTED.
FREEZING RAIN TOTALS OF A TRACE TO A TENTH OF AN INCH ARE EXPECTED
ACROSS CENTRAL LOWER MICHIGAN. THE PRECIPITATION WILL TAIL OFF
THIS AFTERNOON AND END AS A MIX OF RAIN AND SNOW.
- WARMER WITH RAIN THURSDAY AND FRIDAY
OUR UPPER PATTERN SHIFTS TO A WARMER SOUTHWEST FLOW ON THURSDAY
AND FRIDAY. SURFACE LOW PRESSURE WILL LIFT THROUGH THE AREA DURING
THIS TIME FRAME AND BE A FOCUS FOR HEAVIER RAINFALL. RAINFALL
AMOUNTS LOOK TO BE ON THE ORDER OF A HALF INCH TO AN INCH. PWAT
VALUES WILL RISE TOWARD 0.90 WHICH IS WELL ABOVE THE 90 PERCENTILE
FOR THIS WEEK. WHAT SNOWPACK REMAINS WILL CERTAINLY MELT OFF
DURING THE LATTER HALF OF THE WORK WEEK. THE WARMEST DAY OF THE
WEEK LOOKS TO BE THURSDAY WITH HIGHS RISING TO AROUND 50 ALONG
I-94, THE MIDDLE 40S ALONG I-96 AND THE LOW 40S UP NEAR U.S. 10.
WE ARE NOT EXPECTING ANY HYDRO/FLOODING ISSUES GIVEN A LIMITED
SNOWPACK AND GENERALLY LESS THAN AN INCH OF RAIN. WITHIN BANK
RISES ON AREA RIVERS WILL CERTAINLY OCCUR.
- COLDER WITH CHANCES FOR SNOW THIS WEEKEND
COLDER AIR BRIEFLY SETTLES IN FOR SATURDAY INTO SUNDAY AS AN UPPER
TROUGH DIGS ACROSS THE GREAT LAKES REGION. A LOW ASSOCIATED WITH
THE UPPER TROUGH WILL MOVE THROUGH AS WELL AND BRING A MIX OF RAIN
AND SNOW INITIALLY THAT WILL CHANGE TO ALL SNOW AS WE HEAD INTO
SATURDAY NIGHT AND SUNDAY. THE SNOW DOES NOT LOOK HEAVY AT THIS
TIME. HIGHS ON SUNDAY WILL BE IN THE UPPER 20S TO AROUND 30.
AVIATION /06Z TAFS THROUGH 06Z WEDNESDAY/
ISSUED AT 1142 PM EST MON JAN 5 2026
LOW CLOUDS HAVE NOW CLEARED OUT OF ALL OF THE TERMINALS, WITH KMKG
BEING THE LAST SITE WITHIN THE LAST HOUR. MID CLOUDS UP AROUND
10-15K FT AGL REMAIN TO START THE FORECAST PERIOD. MOST SITES ARE
MVFR TO START WITH SOME LIGHT FOG IN PLACE AND VISIBILITIES AROUND
4-6SM.
WE WILL SEE PRECIPITATION BREAK OUT AT THE TERMINALS LIKELY
BETWEEN 10-12Z. THE LATEST TRENDS INDICATE THAT TEMPS SHOULD BE
ABOVE FREEZING AT ALL OF THE TERMINALS WHEN IT BEGINS, OR IT WILL
JUMP VERY QUICKLY AS THE WARMER RAIN FROM ABOVE WARMS THE SFC.
WITHIN 2-4 HOURS OF THE RAIN BEGINNING, CONDITIONS ARE EXPECTED TO
DROP TO IFR. SITES WILL EVENTUALLY GO TO LIFR BY TOMORROW
AFTERNOON, AND STAY THERE THROUGH THE REMAINDER OF THE PERIOD.
FOR GRR 06Z UPDATE...
THE 25% CHANCE MENTIONED IN THE MESSAGING EARLIER HAS LIKELY
DROPPED A BIT MORE. THE CHANCE IS STILL NOT ZERO, BUT LATEST DATA
GIVES A HIGH LIKELIHOOD TEMPS WILL BE A COUPLE OF DEGREES ABOVE
FREEZING WHEN PRECIPITATION STARTS.
GRR WATCHES/WARNINGS/ADVISORIES
MI...WINTER WEATHER ADVISORY UNTIL 1 PM EST THIS AFTERNOON FOR
MIZ037>040-043>046-051-052.
MARINE...NONE.
DISCUSSION...DUKE
AVIATION...NJJ
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