642
FXUS63 KGRR 072004
AFDGRR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND RAPIDS MI
304 PM EST WED JAN 7 2026
KEY MESSAGES
- UNSEASONABLE WARMTH AND MELTING SNOW THIS WEEK
- WIDESPREAD RAIN THURSDAY NIGHT AND RIVER RISES
- RAIN CHANGING TO SNOW ON SATURDAY
DISCUSSION
ISSUED AT 304 PM EST WED JAN 7 2026
- UNSEASONABLE WARMTH AND MELTING SNOW THIS WEEK
OUR OVERALL WEATHER PATTERN ACROSS MOST OF THE COUNTRY RIGHT NOW IS
ACTUALLY FAIRLY ZONAL, WITH A SIGNIFICANT WARM FRONT NEARLY
STATIONARY SOUTH OF THE STATE OF MICHIGAN. THIS ZONAL PATTERN IS
STARTING TO SLOWLY AMPLIFY AHEAD OF WHAT WILL BECOME A MUCH MORE
ACTIVE WEATHER PATTERN FOR THE END OF THIS WEEK. WITH A WEAK
SUBSIDENCE INVERSION OVERHEAD, AND LOTS OF MELTING SNOW AND
MOISTURE FROM RECENT RAINFALL STUCK IN THE BOUNDARY LAYER, WE'RE
IN DAY 2 OF A VERY GLOOMY WEST MICHIGAN WEATHER PATTERN. WHILE
MUCH OF THE FOG DISSIPATED AFTER SUNRISE TODAY, WE STAY VULNERABLE
TO AREAS OF FOG REDEVELOPING THROUGH AT LEAST THE FIRST HALF OF
THE NIGHT BEFORE BOUNDARY LAYER WINDS SHIFT TO SOUTHWESTERLY AND
START TO INCREASE IN STRENGTH AFTER MIDNIGHT.
THIS DEEPENING SOUTHWEST FLOW BEGINS TO DEVELOP IN RESPONSE TO AN
AMPLIFICATION OF THE OVERALL CONUS WEATHER PATTERN. AN UPPER
DISTURBANCE CURRENTLY IN THE BASE OF THE TROUGH MAKING LANDFALL
ACROSS THE BAJA PENINSULA WILL SWEEP RAPIDLY NORTHEAST TOMORROW. AS
IT DOES, A SIGNIFICANT SURFACE LOW WILL START TO TAKE SHAPE ON THE
EAST SIDE OF THE ROCKIES AND STRENGTHEN TO NEAR 994 MB OVER SOUTHERN
WISCONSIN THURSDAY EVENING. AS THE WIND FIELDS RESPOND TO THIS
STRENGTHENING LOW, THE STRONG WARM FRONT TO OUR SOUTH WILL ROAR INTO
LOWER MICHIGAN TOMORROW AND STICK AROUND THROUGH FRIDAY. HIGH
TEMPERATURES MAKE A RUN AT 50 DEGREES ALONG/SOUTH OF I-96 TOMORROW
AND WILL PROBABLY BE SEVERAL DEGREES WARMER ON FRIDAY (ESPECIALLY IN
THE EASTERN AREAS).
MEANWHILE, MODERATE TEMPERATURES OF THE LAST FEW DAYS HAVE
CONDITIONED MUCH OF THE REMAINING SNOWPACK TO MELT QUICKLY ONCE
TEMPERATURES JUMP INTO THE 40S. BY FRIDAY AFTERNOON, WE'RE EXPECTING
A COMPLETE LOSS OF SNOWPACK AT MOST AREAS SOUTH OF US-10, AND UP TO
HALF OF THE SNOWPACK TO MELT NORTH OF US-10 UP TOWARD CADILLAC.
- WIDESPREAD RAIN THURSDAY NIGHT AND RIVER RISES
IN ADDITION TO UNSEASONABLY WARM TEMPERATURES, WE ARE STILL ON TRACK
FOR A WIDESPREAD SOAKING RAIN FOR MOST OF THE AREA. A SUBTLE TREND
HAS CONTINUED TODAY AMONG GUIDANCE FOR A SLIGHTLY MORE
NORTHWESTERLY LOW TRACK (WHICH IS CONSISTENT WITH A STRONGER
SYSTEM COMPARED TO A FEW DAYS AGO). THIS PUTS THE HEAVIEST RAIN
NORTH AND WEST OF US, BUT STILL PRODUCES ABOUT ONE-HALF INCH OF
RAIN FOR MOST OF OUR AREA - WITH SLIGHTLY HIGHER AMOUNTS NEAR
LUDINGTON AND SLIGHTLY LOWER AMOUNTS NEAR JACKSON. A FEW HUNDRED
JOULES OF CAPE ALSO MAKE THEIR WAY INTO OUR SOUTHERN COUNTIES
THURSDAY NIGHT, SO A RUMBLE OF THUNDER CAN'T BE COMPLETELY RULED
OUT EITHER.
COMBINED WITH THE SNOWMELT RUNOFF, THIS SHOULD EVENTUALLY GET PRETTY
GOOD RISES GOING ON MANY OF OUR RIVERS. THANKFULLY, WE HAVE ENOUGH
ROOM IN THE RIVERS RIGHT NOW SUCH THAT SIGNIFICANT FLOODING IS NOT
EXPECTED. HOWEVER, ANY AREAS THAT DO STILL HAVE ICE LEFT ON THE
RIVERS SHOULD MONITOR CLOSELY IN CASE ICE JAMS FORM, BUT WE'RE NOT
CURRENTLY EXPECTING THIS TO BECOME A MAJOR ISSUE.
- RAIN CHANGING TO SNOW ON SATURDAY
THE FORECAST FOR THIS WEEKEND REMAINS A BIT UNCERTAIN, AS A WAVE
MOVING NORTH ALONG THE LARGE BAROCLINIC ZONE DRAPED ACROSS THE
COUNTRY MERGES WITH AN APPROACHING NORTHERN STREAM TROUGH
DIRECTLY OVERHEAD THE GREAT LAKES REGION. IT'S LIKELY WE'LL GET
ANOTHER ROUND OF RELATIVELY LIGHT PRECIPITATION ON SATURDAY THAT
STARTS AS RAIN BUT CHANGES TO SNOW AS COLD AIR INVADES FROM THE
WEST. ACCUMULATIONS LOOK FAIRLY TAME, WITH 25TH/75TH PERCENTILE
SNOWFALL ON THE ECE ON THE ORDER OF 1-4 INCHES (AT GRAND RAPIDS).
HOWEVER, THE TIMING OF THE COLD AIR ARRIVAL AND SUBSEQUENT RAIN-
TO-SNOW TRANSITION WILL BE KEY HERE, AND IF THE COLD AIR ARRIVES
SOONER WE COULD SEE SNOW TOTALS MOVE TOWARD THE HIGHER END OF THAT
RANGE.
BY SUNDAY, 850 MB TEMPERATURES WILL HAVE DROPPED DOWN TO A MORE
SEASONABLE -11C WHICH WILL BEGIN TO TURN ON THE LAKE EFFECT
MACHINE ONCE AGAIN, POTENTIALLY ADDING A FEW MORE INCHES ALONG THE
LAKESHORE, BUT THESE DETAILS ARE STILL MURKY THIS FAR OUT.
AVIATION /18Z TAFS THROUGH 18Z THURSDAY/
ISSUED AT 1218 PM EST WED JAN 7 2026
GENERALLY IFR WITH INTERMITTENT LIFR IS ONGOING THIS AFTERNOON
WITH SLOW IMPROVEMENT THIS AFTERNOON AND THIS EVENING. LOW CIGS
SCATTER OUT OVERNIGHT, HOWEVER PERSISTENT LOW-LEVEL MOISTURE WILL
BRING FOG POTENTIAL ONCE CLOUDS EXIT. WINDS OF 20+ KNOTS IN THE
LOWEST 1KFT MAKE THIS UNCERTAIN SO HAVE GONE BORDERLINE IFR FOR
NOW. PROBABILISTIC GUIDANCE SUGGESTS A 20-35% CHANCE OF IFR
VISBYS OVERNIGHT. THE ONLY EXCEPTION TO THE OVERALL IMPROVEMENT
THIS AFTERNOON/EVENING IS AT MKG WHERE A PERIOD OF ONSHORE FLOW
MAY LEAD TO DETERIORATION FROM 21Z-3Z. THURSDAY MORNING BRINGS THE
ARRIVAL OF A CIRRUS DECK AND VFR CONDITIONS, ALONG WITH LLWS AT
MKG, GRR, AZO, AND BTL AS WINDS AT 2KFT CLIMB TO 40-45 KTS.
GRR WATCHES/WARNINGS/ADVISORIES
MI...NONE.
MARINE...NONE.
DISCUSSION...AMD
AVIATION...THOMAS
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