786
FXUS63 KGRR 211141
AFDGRR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND RAPIDS MI
641 AM EST WED JAN 21 2026
KEY MESSAGES
- MODERATE TO HEAVY SNOW THIS MORNING
- MODERATE SNOW AGAIN TONIGHT THEN LIGHTER SNOW INTO THE WEEKEND
- COLD AIR ARRIVES THURSDAY NIGHT, DANGEROUS COLD THIS WEEKEND
DISCUSSION
ISSUED AT 312 AM EST WED JAN 21 2026
- MODERATE TO HEAVY SNOW THIS MORNING
CURRENTLY, WE AN UPPER PV MAXIMUM CROSSING THE MIDWEST, WITH
SATELLITE INDICATING A CLASSIC BAROCLINIC LEAF SIGNATURE OVER THE
MISSOURI/IOWA BORDER. SURFACE RESPONSE TO THIS FEATURE IS EVIDENT
WITH A PRESSURE MINIMUM OVER SOUTHEAST IA AND PRESSURE FALLS
MAXIMIZED ACROSS NORTHERN IL. A BAND OF SNOW ASSOCIATED WITH FGEN
AND ISENTROPIC ASCENT NORTH OF A WARM FRONT IS NOTED EAST-
NORTHEAST OF THE SURFACE LOW ALONG THE WI/IL BORDER.
CLOSER TO HOME, WE HAVE SEEN AN INITIAL BURST OF SNOW IMPACTING THE
WINTER STORM WARNED AREA OF OTTAWA, MUSKEGON, AND OCEANA COUNTIES.
NUMEROUS OBSERVATION SITES SHOW BACKING WINDS JUST ONSHORE,
INDICATING A RESPONSE TO STRONG FRONTOGENESIS UNDERWAY ALONG THE
LAKE/LAND AIR DENSITY GRADIENT. RADAR RETURNS ARE BLOSSOMING OVER
SOUTHERN LAKE MI WITH THE APPROACH OF THE PREVIOUSLY MENTIONED
FGEN BAND, SO EXPECT MODERATE TO HEAVY SNOWFALL INTENSITIES TO
PERSIST INTO AND BEYOND THE MORNING COMMUTE. LARGEST HOURLY RATES
COULD ACTUALLY OCCUR IN THE 8 TO 9 AM TIMEFRAME FOR SOME AREAS AS
THE WIND CONVERGENCE AXIS ASSOCIATED WITH THE FGEN REGION PIVOTS
IN AN ONSHORE ORIENTATION.
SNOW AMOUNTS GENERALLY LOOK ON TRACK. HOWEVER, WOULD NOT BE
SURPRISED TO SEE SOUTHERN MASON COUNTY GET 8 INCHES. THIS IS NOT
HIGH CONFIDENCE HOWEVER AND WILL KEEP THE ADVISORY GOING THERE
INSTEAD OF UPGRADING TO A WARNING. AS NOTED PREVIOUSLY, THE ENTIRE
REGION CAN EXPECT CONTINUING, ALBEIT LIGHTER, SNOW LASTING INTO THE
AFTERNOON AND EVENING.
- MODERATE SNOW AGAIN TONIGHT THEN LIGHTER SNOW INTO THE WEEKEND
ANOTHER CLIPPER-LIKE PV MAX THAT CURRENTLY IS DROPPING INTO THE
NORTHERN PLAINS WILL PROVIDE ANOTHER ROUND OF LAKE ENHANCED
SNOWFALL. THUS, THURSDAY WILL OFFER YET ANOTHER CHALLENGING COMMUTE.
AS NOTED PREVIOUSLY, WE WILL CONTINUE TO SEE EPISODIC LAKE ENHANCED
SNOW INTO THE WEEKEND, BUT AMOUNTS SHOULD BE MORE ANEMIC GIVEN THE
ARRIVAL OF BITTERLY COLD AIR THAT WILL YIELD EXCEPTIONALLY POOR
MICROPHYSICS FOR SNOW PRODUCTION.
- COLD AIR ARRIVES THURSDAY NIGHT, DANGEROUS COLD THIS WEEKEND
TEMPERATURES WILL PLUMMET THURSDAY NIGHT, LIKELY DROPPING BELOW ZERO
BY 7 AM FRIDAY OVER CENTRAL INTERIOR LOWER MI. THE GEFS AND EC
ENSEMBLE INDICATE A GREATER THAN 90 PERCENT CHANCE OF APPARENT
TEMPERATURES ALREADY COLDER THAN -15F BY 7 AM FRIDAY FROM I-96
NORTHWARD, SO COLD WEATHER PREPARATIONS WILL NEED TO BE IN PLACE
EARLY. FRIDAY NIGHT LOOKS EVEN MORE IMPRESSIVE. THE EC ENSEMBLE,
WHICH HAS BEEN VERY CONSISTENT IN ADVERTISING BITTERLY COLD
TEMPERATURES DURING THIS TIME, GIVES A GREATER THAN 70 PERCENT
CHANCE OF APPARENT TEMPERATURES -25F OR COLDER OVER INTERIOR LOWER
MICHIGAN SATURDAY MORNING. EXTREME SOUTHWEST LOWER MAY BE SPARED
THE BITTEREST COLD DUE TO LAKE-MODIFIED AIR. EVEN ON SUNDAY
MORNING, INTERIOR LOWER MI IS LOOKING AT GREATER THAN A 50
PERCENT CHANCE OF -15F APPARENT TEMPERATURES. ALL OF THIS IS TO
SAY THAT DANGEROUS COLD CAN BE EXPECTED OVER MUCH OF THIS
WEEKEND.
ALTHOUGH TEMPERATURES WILL MODERATE SOME NEXT WEEK, THEY WILL REMAIN
BELOW NORMAL. THERE IS A SIGNAL FOR A GULF LOW LIFTING TOWARDS THE
OH VALLEY IN THE SUNDAY/MONDAY TIMEFRAME AHEAD OF AN APPROACHING
PHASED UPPER TROUGH, BUT IT'S WAY TOO EARLY TO NAIL DOWN SPECIFICS
ABOUT ITS TRACK AND WHERE PRECIPITATION WILL OCCUR.
AVIATION /12Z TAFS THROUGH 12Z THURSDAY/
ISSUED AT 641 AM EST WED JAN 21 2026
NO MAJOR CHANGES FOR THIS FORECAST UPDATE. A GROWING AREA OF
MODERATE TO HEAVY SNOW WILL CONTINUE TO SPREAD EASTWARD FROM LAKE
MICHIGAN CAUSING PERSISTENT IFR VISIBILITY RESTRICTIONS MOST OF
THIS MORNING. MODEL GUIDANCE SUGGESTS THAT SNOWFALL INTENSITY
COULD PEAK IN THE 12-14Z TIMEFRAME SO HAVE INCLUDED TEMPO LIFR
GROUPS WITH VISIBILITIES OCCASIONALLY DROPPING BELOW 1 MILE DURING
THAT TIME. AFTER 16-18Z, WE EXPECT A TRANSITION TO MVFR
RESTRICTIONS IN LIGHT SNOW THAT MAY TAPER OFF COMPLETELY BY LATE
AFTERNOON. ANOTHER ROUND OF SNOW IS EXPECTED TO COMMENCE AFTER 00Z
TONIGHT, BRINGING ANOTHER PERIOD OF IFR RESTRICTIONS.
MARINE
ISSUED AT 312 AM EST WED JAN 21 2026
NO CHANGES PLANNED TO THE CURRENT FORECAST. WE WILL BE EASING INTO
GALE CONDITIONS FOR MUCH OF THE AREA THIS AFTERNOON. HEAVY
FREEZING SPRAY WILL ALSO BE A CONCERN, ESPECIALLY THURSDAY NIGHT
INTO FRIDAY.
GRR WATCHES/WARNINGS/ADVISORIES
MI...WINTER WEATHER ADVISORY UNTIL 10 AM EST THIS MORNING FOR MIZ037-
038-044>046-051-052-057>059-064>067-071>074.
WINTER STORM WARNING UNTIL 10 AM EST THIS MORNING FOR MIZ043-050-
056.
MARINE...SMALL CRAFT ADVISORY UNTIL 4 PM EST THIS AFTERNOON FOR
LMZ844>849.
GALE WARNING FROM 4 PM THIS AFTERNOON TO 7 AM EST FRIDAY FOR
LMZ844>848.
HEAVY FREEZING SPRAY WARNING FROM 10 PM THIS EVENING TO 4 AM EST
SATURDAY FOR LMZ844>849.
DISCUSSION...TJT
AVIATION...TJT
MARINE...TJT
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