954
FXUS63 KGRR 101825
AFDGRR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND RAPIDS MI
125 PM EST SAT JAN 10 2026
KEY MESSAGES
- WIDESPREAD PRECIPITATION TODAY, LAKE EFFECT SNOW SHOWERS TONIGHT
- PERIODIC RAIN/SNOW CHANCES MUCH OF THE COMING WEEK
- STRONGER SYSTEM WITH COLDER AIR ARRIVES LATE IN THE WEEK
DISCUSSION
ISSUED AT 337 AM EST SAT JAN 10 2026
- WIDESPREAD PRECIPITATION TODAY, LAKE EFFECT SNOW SHOWERS TONIGHT
NO CHANGES NEEDED TO THE GOING WINTER WEATHER ADVISORY WITH THIS
FORECAST PACKAGE. LATEST SET OF DATA CONTINUES TO SUPPORT THE
ADVISORY WELL OVER THE NW CORNER OF THE FORECAST AREA WITH AMOUNTS
TAPERING OFF TO THE SOUTH AND EAST.
THIS EVENT TODAY IS BEING DRIVEN LARGELY BY A STRENGTHENING UPPER
JET CORE, WITH THE LEFT FRONT EXIT REGION PASSING OVER THE NW
COUNTIES EARLY THIS AFTERNOON. THIS JET STREAK IS STRENGTHENING AS
THE NEXT STRONG WAVE COMES IN AND STRENGTHENS THE GRADIENT A BIT. UP
OVER THE FAVORED NW AREA, IT IS COLD ENOUGH FOR ALL SNOW AND SNOW TO
LIQUID RATIOS (SLR) WILL BE THE HIGHEST THERE. THE ORIENTATION OF
THE HEAVIEST SNOW GIVES THE IMPRESSION THERE IS A LAKE ENHANCEMENT
TO IT, BUT IT IS NOT WITH THE LOW LEVEL FLOW OFFSHORE THROUGH MUCH
OF THE EVENT.
FURTHER SOUTH, WE WILL SEE LIGHTER PRECIPITATION RATES BEING FURTHER
REMOVED FROM THE BEST FORCING MENTIONED ABOVE. IN ADDITION, SFC
TEMPS ABOVE FREEZING, AND A MELTING LAYER AROUND 1500 FT WILL ALLOW
SOME OF THE PRECIPITATION TO FALL AS RAIN TOWARD I-94. EVEN IF SNOW
FALLS THERE, IT WILL BE ASSOCIATED WITH LOW SLRS, SO AMOUNTS WILL BE
MINIMAL THROUGH TODAY DOWN THERE.
WE WILL SEE A LULL IN THE PRECIPITATION VERY LATE THIS AFTERNOON AND
EVENING, BEFORE ANOTHER BATCH OF SNOW SHOWERS DEVELOPS/MOVES IN. WE
WILL LOSE THE FORCING WITH THE UPPER JET BY THIS EVENING. WE SEE A
PERIOD OF SLIGHT RIDGING ALOFT IN THE UPPER AIR PATTERN OUT AHEAD OF
THE MAIN UPPER LOW AND ANOTHER SHORT WAVE ROTATING AROUND IT AND
INTO THE REGION. AS THE ENERGY MOVES IN LATER THIS EVENING AND
OVERNIGHT, SNOW SHOWERS WILL THEN SPREAD SOUTHWARD THROUGH THE AREA.
SOME LAKE ENHANCEMENT IS EXPECTED TO OCCUR AS 850 MB TEMPS DROP INTO
THE NEGATIVE MID TEENS, AND THE FLOW BECOMES ONSHORE.
HEAVY AMOUNTS OF SNOW ARE NOT EXPECTED TONIGHT. THAT IS DUE TO THE
PROGRESSIVE NATURE OF THE MAIN LOW AND SHORT WAVE. THE FLOW WILL BE
CONSTANTLY CHANGING, UNTIL THE ENTIRE LOW COMPLEX MOVES OUT SUNDAY
MORNING. THE CYCLONIC FLOW ALOFT MOVES OUT, AND LAKE EFFECT WILL
TAPER OFF THROUGH SUNDAY.
- PERIODIC RAIN/SNOW CHANCES MUCH OF THE COMING WEEK
WE WILL SEE A RETURN TO THE UPPER FLOW COMING IN FROM THE WNW, AFTER
THE BREAK IN DOMINANT PATTERN THIS WINTER SO FAR WITH THE WARMER SW
FLOW. THE WESTERN RIDGE WILL REBUILD, AND SET THE FLOW FROM THE WNW
ONCE AGAIN.
WE WILL BE ON THE SOUTHERN EDGE OF THIS FLOW, SO WE WILL NOT BE
UNDER THE INFLUENCE OF THE CYCLONIC FLOW OR COLD POOL ALOFT. WE WILL
BE CLOSE ENOUGH HOWEVER TO SEE THE PERIODIC CHANCES FOR
PRECIPITATION. THIS IS EVIDENT IN THE SHORT WAVE COMING THROUGH ON
TUESDAY. MUCH OF THE AREA IS LIKELY TO SEE MORE RAIN THAN SNOW WITH
THIS SYSTEM AS 850 MB TEMPS ARE ABOVE 0C AND A SUFFICIENT SOUTHERLY
LOW LEVEL FLOW AHEAD OF THE SYSTEM WILL KEEP SFC TEMPS ABOVE
FREEZING.
WE WILL SEE COOLER AIR FILTER IN ON WEDNESDAY BEHIND THE TUESDAY
SYSTEM. ANOTHER SHORT WAVE WILL ARRIVE FOR WEDNESDAY, AND SUPPORT
LIGHT SNOW CHANCES ACROSS MUCH OF THE AREA AT THAT TIME. NO
SIGNIFICANT AMOUNTS OF SNOW ARE EXPECTED WITH THE SPEED OF THE
SYSTEM, AND LIMITED MOISTURE ASSOCIATED WITH IT.
WE WILL SEE TEMPERATURES CONTINUE TO GET PROGRESSIVELY COOLER THEN
BEHIND THE WEDNESDAY SYSTEM AS THE UPPER FLOW WILL BECOME MORE
NORTHERLY AHEAD OF THE BUILDING RIDGE OVER THE WESTERN HALF OF THE
COUNTRY. TEMPERATURES AT 850 MB IN THE NEGATIVE TEENS WOULD BE
SUFFICIENT FOR LAKE EFFECT. HOWEVER, RIDGING AT THE SFC AND ALOFT
WILL SQUASH SNOW CHANCES ON THURSDAY.
- STRONGER SYSTEM WITH COLDER AIR ARRIVES LATE IN THE WEEK
THE MORE AMPLIFIED FLOW DEVELOPING ACROSS THE COUNTRY THROUGH THE
WEEK WILL EVENTUALLY ALLOW A STRONGER UPPER LOW TO BE CARVED OUT
OVER THE GREAT LAKE REGION BY FRIDAY. WE SEE A STRONGER CLIPPER
BRING SOME TEMPORARY WARMER IN BRIEFLY, BUT THEN DROPS THE TEMPS
QUICKLY BEHIND IT NEXT FRIDAY NIGHT. THIS WILL INCREASE THE THREAT
OF LAKE EFFECT WITH COLDER TEMPS.
AVIATION /18Z TAFS THROUGH 18Z SUNDAY/
ISSUED AT 125 PM EST SAT JAN 10 2026
THIS TAF PERIOD WE BEGIN WITH WIDESPREAD IFR AND LOWER CIGS AND
VSBYS AT MKG, GRR, AZO, AND BTL. MKG AND GRR ARE BOTH LIFR VSBYS
WITH LIFR CIGS AT TIMES.
LATEST RADAR SHOWS THE HEAVIEST SNOW BANDS CONTINUE TO MOVE
THROUGH THE REGION THROUGH 20Z. EXPECT PERIODS OF MIXED
PRECIPITATION AT THE SOUTHERN TAF SITES, ESPECIALLY AZO AND BTL.
TEMPERATURES WILL DROP THROUGHOUT THE DAY AND WILL SWITCH OVER TO
SNOW EVENTUALLY. THERE IS SOME DISPARITY ON WHEN THAT WILL HAPPEN.
RAIN TO SNOW AT AZO, BTL WILL BE BETWEEN 21Z AND 01Z.
SNOW THROUGH THE NORTHERN TAF SITES WILL LIGHTEN AFTER 20Z AS THE
BACK EDGE OF THE FRONT MOVES THROUGH.
THERE WILL BE SOME IMPROVEMENT IN VSBYS THIS EVENING BEFORE LAKE
EFFECT FLOW TAKES OVER. EXPECT MVFR TO VFR VSBYS AFTER 00Z AT MKG
AND GRR BEFORE THEY DROP BACK DOWN AROUND 09Z AS LAKE EFFECT FLOW
INCREASES.
THOSE SHOWERS WILL THEN BRING VSBYS AND CIGS BACK TO MVFR WITH
PERIODS OF IFR POSSIBLE BETWEEN 11Z AND 15Z.
MARINE
ISSUED AT 337 AM EST SAT JAN 10 2026
NOT MUCH OF A REPRIEVE IN THE WINDS/WAVES AFTER FRIDAY'S EVENT, AND
THE NEXT EVENT BEGINNING THIS AFTERNOON AND CONTINUING THROUGH
SUNDAY MORNING. HIGH PRESSURE AND A WEAK GRADIENT IS OVERHEAD RIGHT
NOW, BUT WILL MOVE OUT QUICKLY THIS MORNING. THIS WILL ALLOW WINDS
TO COME UP THIS AFTERNOON, AND MAX OUT VERY LATE TONIGHT/EARLY
SUNDAY MORNING AS GALES WITH THE ARRIVAL OF THE COLDER AIR.
GRR WATCHES/WARNINGS/ADVISORIES
MI...WINTER WEATHER ADVISORY UNTIL 1 PM EST SUNDAY FOR MIZ037>039-
043>045-050.
MARINE...SMALL CRAFT ADVISORY UNTIL 4 AM EST SUNDAY FOR LMZ844>849.
GALE WARNING FROM 4 AM TO 1 PM EST SUNDAY FOR LMZ844>849.
DISCUSSION...NJJ
AVIATION...CERU
MARINE...NJJ
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