480
FXUS63 KGRR 280123
AFDGRR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND RAPIDS MI
923 PM EDT MON APR 27 2026
KEY MESSAGES
- A PERIOD OF STRONG WINDS LIKELY THIS AFTERNOON AND EVENING
- TURNING PROGRESSIVELY COLDER THIS WEEK; FROSTS & FREEZES COMING
DISCUSSION
ISSUED AT 235 PM EDT MON APR 27 2026
- A PERIOD OF STRONG WINDS LIKELY THIS AFTERNOON AND EVENING
A DEEPENING SPRINGTIME LOW WILL BE MOVING FROM IA TOWARD THE WESTERN
U.P. TONIGHT AS A SHORTWAVE TROUGH SWINGS THROUGH THE REGION.
PERIODS OF SHOWERS AND A FEW THUNDERSTORMS WILL ACCOMPANY THIS
SYSTEM. STRONG DEEP LAYER SHEAR MOVES IN AFTER 20Z BUT WITH AN
ABSENCE OF CAPE. VERY LITTLE MLCAPE IS INDICATED BY THE 12Z HRRR
FOR THE REMAINDER OF TODAY AND TONIGHT, WITH PERHAPS 500+ J/KG OF
MUCAPE MOVING IN PRIOR TO FROPA OVERNIGHT.
WHILE INSTABILITY WILL BE OUR MAIN LIMITING FACTOR FOR ORGANIZED
CONVECTION, THE VERY STRONG WIND FIELDS JUST OFF THE SURFACE ARE
CONCERNING WITH 50-60 KTS INDICATED FROM 925-850MB THIS AFTERNOON
AND EVENING. WHAT WE'VE SEEN WITH THE 12Z CAM GUIDANCE IS A SIGNAL
FOR WAKE LOW WIND GUSTS IN THE POST-STRATIFORM RAIN REGION ON THE
NORTH SIDE OF A CONVECTIVE COMPLEX MOVING ACROSS IL/MO AND THAT
HAS CERTAINLY BORE OUT IN REALITY. SEVERAL SITES ACROSS IA AND NOW
IL HAVE GUSTED IN THE 45-55 MPH RANGE BEHIND THE STRATIFORM PRECIP
REGION MOVING THROUGH METRO CHICAGO. THIS IS COINCIDENT WITH 3
HOUR PRESSURE DROPS AROUND 8-10 MB. WE FEEL THE BEST WAY TO HANDLE
THIS IS WITH A WIND ADVISORY AS OPPOSED TO THE LESS VISIBLE SPS.
IF A SMALL AREA OF HIGHER GUSTS MATERIALIZE THEN PERHAPS SVRS WILL
BE NEEDED, OR IF A LARGER SCALE, A HIGH WIND WARNING MAY BE
CONSIDERED. THE ADVISORY WILL BE IN PLACE THROUGH 8PM BUT COULD
BE EXTENDED IF THE THREAT GOES LONGER THAN ANTICIPATED.
ANY ADDITIONAL SHOWERS AND STORMS THAT DEVELOP LATE TONIGHT AND
INTO THE OVERNIGHT HOURS WILL LIKELY BE FAIRLY TAME BUT COULD PUT
DOWN SOME SWATHS OF 0.50" OR MORE OF RAIN CREATING BRIEF PONDING
OF WATER ON ROADS OVERNIGHT BEFORE THAT THREAT DIMINISHES.
- TURNING PROGRESSIVELY COLDER THIS WEEK; FROSTS & FREEZES COMING
ENSEMBLE GUIDANCE IS IN GOOD AGREEMENT REGARDING UPPER TROUGHING
SETTLING IN THIS WEEK AND BELOW NORMAL TEMPERATURES MOVING IN.
MEAN 850MB TEMPERATURES ARE SHOWN TO DIP TO AROUND -5C BY LATE
WEEK. SEVERAL NIGHTS OF FROSTS AND FREEZES ARE LIKELY TO
MATERIALIZE ACROSS MOST OF THE REGION STARTING WEDNESDAY NIGHT AND
LASTING THROUGH SATURDAY NIGHT. THE WORST CONDITIONS ARE
ANTICIPATED THURSDAY NIGHT AND FRIDAY NIGHT. BOTH OF THOSE LOOK TO
BE RADIATIONAL EVENTS.
AVIATION /00Z TAFS THROUGH 00Z WEDNESDAY/
ISSUED AT 922 PM EDT MON APR 27 2026
CEILINGS TRENDED VFR TO MVFR OUTSIDE OF THE RECENT SHOWER AND THUNDERSTORM
ROUND. A WAKE LOW PROGRESSED THROUGH THE REGION BEHIND THE ORGANIZED
STORM CLUSTER AND BROUGHT GUSTS UP TO 49 KTS THROUGH THE TERMINALS.
CHANCES FOR SHOWERS AND THUNDERSTORMS CONTINUE TONIGHT. ANOTHER ROUND
OF STRONG SHOWERS WITH EMBEDDED THUNDERSTORMS WILL EXIT THE LAKE OVER
THE REGION NEAR 2-3Z, AND A SECONDARY BURST OF STRONG WINDS IS
POSSIBLE WITH IT. MVFR TO POSSIBLE IFR CONDITIONS CAN BE EXPECTED
WITH THE SHOWERS AND THUNDERSTORMS. VICINITY SHOWERS WILL REMAIN
AS THE BULK OF THE ACTIVITY PUSHES EAST OUT OF THE FORECAST AREA
NEAR 9Z, WHILE CEILINGS TREND MORE SOLIDLY MVFR TO EVENTUALLY VFR.
WINDS WILL REMAIN AN AVIATION CONCERN TONIGHT AS GUSTY SOUTHEAST WIND VEER
TO A MORE SOUTHWESTERLY DIRECTION, AND THEN WESTERLY EARLY TUESDAY
MORNING. OUTSIDE OF A BRIEF LULL IN WINDS TUESDAY MORNING, GUSTS UP
TO 30 KTS ARE LIKELY FOR MOST OF THE TERMINALS THROUGH TUESDAY AFTERNOON.
WINDS WILL THEN EASE TUESDAY EVENING.
MARINE
ISSUED AT 235 PM EDT MON APR 27 2026
A SHORT DURATION GALE WARNING IS BEING ISSUED TO COVER GUSTY WINDS
BEHIND AN AREA OF SHOWERS AND EMBEDDED THUNDERSTORMS MOVING OVER
LAKE MICHIGAN. THESE WIND GUSTS ARE ALREADY OBSERVED TO BE IN
EXCESS OF 50 MPH ACROSS NORTHERN IL AND WOULD LAST LONGER THAN A
TYPICAL THUNDERSTORM WIND GUST WOULD. THE WIND DIRECTION WOULD BE
FROM THE E/SE. FOLLOWING THE GALE, A SMALL CRAFT ADVISORY GOES
INTO EFFECT TO COVER BUILDING WAVES AND ELEVATED WINDS OVER THE
LAKE INTO TUESDAY.
GRR WATCHES/WARNINGS/ADVISORIES
MI...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 6 PM EDT TUESDAY FOR LMZ844>849.
DISCUSSION...HOVING
AVIATION...EAK
MARINE...HOVING
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