312
FXUS63 KGRR 040813
AFDGRR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND RAPIDS MI
313 AM EST WED FEB 4 2026
KEY MESSAGES
- LIGHT SNOW THU-FRI WITH A CHANCE OF FREEZING DRIZZLE THU EVENING
- COLDER THIS WEEKEND WITH LIGHT LAKE EFFECT ALONG THE LAKESHORE
- MODERATING TEMPERATURES NEXT WEEK
DISCUSSION
ISSUED AT 313 AM EST WED FEB 4 2026
- LIGHT SNOW THU-FRI WITH A CHANCE OF FREEZING DRIZZLE THU EVENING
PLENTY OF STRATOCUMULUS CLOUDS OVER THE AREA THIS MORNING, WITH THE
RADAR SHOWING PLENTY OF FLURRIES ACCOMPANYING THE CLOUDS. HIGH
PRESSURE IS BUILDING IN, BUT THIS MOISTURE IS TRAPPED UNDER THE
SUBSIDENCE INVERSION. IT IS RATHER SHALLOW WITH CLOUD BASES AROUND
2500-3000 FT AND THE TOPS OF THE CLOUDS 4-5K FT PER THE KGRR VWP.
EVEN THOUGH THE MOISTURE IS SHALLOW, THE DGZ IS SQUARELY IN THE
CLOUD LAYER, LEADING TO THE FLURRIES. THERE ARE LIKELY SOME SHALLOW
LAKE EFFECT SNOW SHOWERS OVER THE LAKE THAT WILL MOVE ONSHORE TODAY
AS THE LOW LEVEL FLOW BECOMES WESTERLY LATER TODAY.
AFTER A FEW FLURRIES PERSISTING THROUGH MOST OF TONIGHT, WE WILL SEE
THE NEXT WIDESPREAD LIGHT SNOW SPREAD OVER THE AREA FROM NW TO SE
THURSDAY MORNING AHEAD OF THE NEXT SHORT WAVE COMING IN ON THE NW
FLOW ALOFT. THIS EVENT DOES NOT LOOK TO BE ANYTHING SPECIAL,
CONSIDERING WHAT THE AREA HAS ENDURED OVER THE LAST MONTH. THE
DURATION LOOKS TO BE A FEW HOURS FROM THE TIME THE LOWER PORTION OF
THE COLUMN SATURATES SUFFICIENTLY, TO WHEN WE LOSE THE MID AND UPPER
LEVEL MOISTURE THURSDAY AFTERNOON. THERE CONTINUES TO LOOK LIKE
THERE WILL BE SOME LAKE ENHANCEMENT FOR THE LAKESHORE, BUT NOTHING
STRONG WITH LOW INVERSION HEIGHTS DUE TO THE DEEP COLD AIR AND
CYCLONIC FLOW ALOFT STAYING NORTH OF THE AREA.
ONE CONCERN THAT CONTINUES TO BE POSSIBLE CENTERED AROUND THURSDAY
EVENING WILL BE A CHANCE OF SOME FREEZING DRIZZLE. AS MENTIONED
ABOVE, WE LOSE THE MID AND UPPER LEVEL MOISTURE BY ABOUT 21Z THU. WE
SEE A WARM FRONT APPROACH THE AREA AT THE SFC, WHILE WE WILL BE IN
BETWEEN UPPER WAVES ALOFT. FORECAST SOUNDINGS AND RH OVERVIEWS
INDICATE THAT THE DGZ WILL BECOME UNSATURATED. THE QUESTION IS DO WE
CONTINUE TO PRECIPITATE OR NOT. IF WE DO, THEN THE TYPE WILL LIKELY
BE FREEZING DRIZZLE UNTIL ABOUT 06Z OR SO WHEN WE SEE THE MID AND
UPPER LEVEL MOISTURE RETURN WITH THE NEXT SHORT WAVE AND COLD FRONT.
THEN ANY PRECIPITATION IS EXPECTED TO CHANGE BACK TO LIGHT SNOW.
THEN AS THE FRONT MOVES THROUGH, WE WILL SEE SNOW END INLAND, AND
SOME LAKE EFFECT TAKE SHAPE ALONG THE IMMEDIATE LAKESHORE.
- COLDER THIS WEEKEND WITH LIGHT LAKE EFFECT ALONG THE LAKESHORE
WE WILL SEE MUCH COLDER AIR MOVE BACK IN OVER THE AREA BEHIND THE
SYSTEM COMING THROUGH ON FRIDAY. 850 MB TEMPS WILL DROP FROM -5C
FRIDAY MORNING, TO ALMOST -19C FRIDAY NIGHT. WE WILL SEE HIGHS ON
FRIDAY WELL INTO THE 30S, AND THEN DROPPING TO THE SINGLE DIGITS
ABOVE ZERO FRIDAY NIGHT.
OBVIOUSLY THIS IS IDEAL INSTABILITY FOR LAKE EFFECT TO TAKE PLACE.
HOWEVER, A BIG LAKE EFFECT IS NOT EXPECTED WITH MANY FACTORS WORKING
AGAINST IT. IN THE BIG PICTURE, WE DO NOT SEE CYCLONIC FLOW TAKE
SHAPE AS THE UPPER JET CORE WILL STAY EAST OF THE AREA. THIS WILL
LIMIT VERTICAL EXTENT OF THE LAKE EFFECT COLUMNS WITH LOWER
INVERSION HEIGHTS. RIDGING BUILDING AT THE SFC WILL ALSO BE A RESULT
OF THIS, AND WILL WORK AGAINST GOOD LAKE EFFECT. WE WILL ALSO SEE
THE FLOW FROM THE NNW, WHICH WILL KEEP LAKE EFFECT CLOSE TO THE
LAKESHORE.
A WEAK SHORT WAVE LOOKS TO APPROACH THE AREA ON SUNDAY, BUT IT WILL
BE MOISTURE STARVED, AND ALL OF THE LIMITING FACTORS MENTIONED FOR
SATURDAY WILL PERSIST INTO SUNDAY. MAX TEMPS ON SUNDAY WILL START TO
MODIFY AS THE COLDEST AIR ALOFT MOVES OUT OF THE AREA.
- MODERATING TEMPERATURES NEXT WEEK
WE WILL SEE THE FLOW ALOFT FROM THE NW PERSIST INTO EARLY NEXT WEEK,
BUT THE ORIGIN OF THE FLOW WILL BE FROM THE PACIFIC AT THAT TIME
WITH THE UPPER RIDGE AXIS JUST WEST OF OUR REGION. ANOTHER SHORT
WAVE COMES THROUGH, BUT THE MAIN FORCING FROM IT WILL STAY MORE
NORTH, AND LIKELY NOT AFFECT OUR FORECAST AREA MUCH, IF AT ALL. THE
RIDGE AXIS WILL THEN BE OVER THE AREA ON TUESDAY.
RETURN FLOW AT THE SFC FROM THE SOUTH WILL HELP TO WARM OUR SFC
TEMPS NICELY FOR MONDAY AND TUESDAY. 850 MB TEMPERATURES WARM TO
NEAR 0 TO +6C BY TUESDAY AFTERNOON. THIS WILL HELP DRIVE MAX TEMPS
TO NEAR 40.
AVIATION /06Z TAFS THROUGH 06Z THURSDAY/
ISSUED AT 1208 AM EST WED FEB 4 2026
SATELLITE IMAGES SHOW MUCH OF LOWER MICHIGAN UNDER MVFR CLOUDS BUT
FOR SOME PATCHY CLEARING. THESE CLOUDS ARE PERSISTING UNDER WEAK
NORTH FLOW AND MOISTURE ADDED BY THE GREAT LAKES. VERY LIGHT SNOW
FLURRIES ARE OCCURRING ESPECIALLY AND GRR AND MKG ALL THE WAY
NORTH TO LAKE SUPERIOR. THERE IS NOT MUCH INDICATION THAT THE
BROADER WEATHER PATTERN WILL SUPPRESS THESE CLOUDS ON WEDNESDAY.
IN GENERAL, MODELS WERE UNDERDOING THE CLOUD COVER THIS EVENING.
LATEST SHORT-TERM MODELS, INCLUDING THE HREF, MAINTAIN MOSTLY
CLOUDY CONDITIONS WITH MVFR CEILINGS THROUGH WEDNESDAY. THE ECMWF
IS BROADLY PAINTING A TRACE OF PRECIP ALL DAY TOO, TO SUPPORT THE
IDEA OF JUST VERY LIGHT SNOW FLURRIES PERSISTING. THIS IS
CERTAINLY THE PATTERN AND THE TIME OF YEAR TO BE PESSIMISTIC WITH
THE CLOUD FORECAST.
GRR WATCHES/WARNINGS/ADVISORIES
MI...NONE.
MARINE...NONE.
DISCUSSION...NJJ
AVIATION...CAS
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