366
FXUS63 KGRR 181856
AFDGRR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND RAPIDS MI
256 PM EDT WED MAR 18 2026
KEY MESSAGES
- MIXED PRECIPITATION LATE TONIGHT-THU MORNING; RAIN POSSIBLE FRI
- WARMER SATURDAY WITH RAIN CHANGING TO SNOW SAT NIGHT-SUN
- DRY EARLY NEXT WEEK WITH SEASONABLE TEMPERATURES
DISCUSSION
ISSUED AT 256 PM EDT WED MAR 18 2026
- MIXED PRECIPITATION LATE TONIGHT-THU MORNING; RAIN POSSIBLE FRI
THE PATCHY FREEZING DRIZZLE THAT WAS OBSERVED AT A FEW LOCATIONS
EARLIER HAS PRETTY MUCH ENDED ACROSS THE AREA PER SFC OBSERVATIONS
ALL ABOVE 6 MILES, AND THE RADAR RETURNS FROM EARLIER HAVING MOVED
OUT. WE CAN NOT RULE OUT A BRIEF PATCH THIS AFTERNOON WITH A FEW
MORE ECHOES ON THE RADAR TOWARD KMKG, HOWEVER IT SHOULD REMAIN MUCH
MORE ISOLATED THIS AFTERNOON.
OUR FOCUS THEN QUICKLY TURNS TO A WAVE OF PRECIPITATION THAT WILL
APPROACH THE AREA AFTER MIDNIGHT AND LAST THROUGH TOMORROW MORNING.
THIS IS A COMPLICATED SETUP, WHICH HAS LED, AND STILL IS PROVIDING A
BIT OF UNCERTAINTY IN THE FORECAST. WE HAVE A FRONT THAT IS DROPPING
DOWN INTO THE AREA, WHILE A SFC WAVE MOVING TO OUR SW IS INTERACTING
WITH THE FRONT.
THIS IS GOING TO LEAD TO A RELATIVELY NARROW BAND OF PRECIPITATION
FOCUSED JUST TO THE NORTH OF THE SFC WAVE. THE EXACT TRACK OF THIS
PRECIPITATION IS LEADING TO A PORTION OF THE UNCERTAINTY. THE OTHER
PART OF THE UNCERTAINTY IS THE TIMING AND THEREFORE SFC TEMPERATURES
WITH REGARDS TO FREEZING OF WHEN THE PRECIPITATION ARRIVES.
THE MOST LIKELY SCENARIO IS THAT THE BAND OF PRECIPITATION WILL
OCCUR SOUTH OF THE I-96 CORRIDOR. THIS IS WHAT PROBABLY THE BEST
CONSENSUS IS AT THIS TIME. HOWEVER, THERE ARE MODEL/ENSEMBLE MEMBERS
THAT TAKE IT NORTH OF THERE, AND OTHERS THAT BRING LITTLE TO NO
PRECIPITATION. THE OTHER LIKELY PART OF THIS SCENARIO IS THAT THIS
PRECIPITATION WILL COME IN BEFORE DAYBREAK THU. THIS INCREASES THE
CHANCE THAT SOME OF THE PRECIPITATION WILL FALL AS FREEZING RAIN.
ALL OF THIS SAID, THERE IS NOT ENOUGH CONFIDENCE TO ISSUE AN
ADVISORY AT THIS TIME.
THE GOOD THING WITH THIS IS THAT WE SHOULD SEE TEMPS WARM ABOVE
FREEZING FOR MOST LOCATIONS BY MID-LATE THURSDAY MORNING. THIS WILL
END THE THREAT OF THE ICING IMPACTS FOR THE AREA, ALONG WITH THE
PRECIPITATION MOVING OUT.
WE WILL SEE ANOTHER SHORT WAVE MOVE THROUGH THE REGION, WITH THIS
ONE FURTHER NORTH THAN TODAY'S AND TONIGHT'S WAVES. WE WILL BE A BIT
WARMER WHEN THIS SYSTEM COMES THROUGH, AND THE PRECIPITATION SHIELD
WITH THIS WILL BE FURTHER NORTH ALSO. THIS SHOULD NOT BE A BIG DEAL
WITH JUST SOME CHANCES FOR RAIN, HIGHEST TO THE NE.
- WARMER SATURDAY WITH RAIN CHANGING TO SNOW SAT NIGHT-SUN
SOUTHERLY FLOW WILL HOLD ON SATURDAY, EVEN IN THE WAKE OF THE FRIDAY
WAVE. THIS IS GOING TO GIVE MAX TEMPS FOR SATURDAY A HEAD START,
WITH MAX TEMPS TOPPING OUT AT LEAST IN THE 50S UP NORTH, AND 60S
DOWN SOUTH. IN FACT, THE FRONT THAT WILL BE COMING DOWN HAS SHOWED A
SLOWING TREND, AND WILL GIVE THE AREA A GOOD CHANCE OF A WARM SPRING
DAY, ESPECIALLY FOR AREAS AWAY FROM LAKE MICHIGAN.
THIS WARM UP WILL BE SHORT LIVED AS A STRONGER UPPER WAVE WILL COME
BY AND PUSH A STRONGER COLD FRONT THROUGH THE AREA. THE FRONTAL
PASSAGE ITSELF SATURDAY NIGHT WILL BE MOSTLY DRY AS THE FLOW AHEAD
OF IT WILL BE COMING FROM THE PLAINS. THIS MEANS THERE WILL BE
LITTLE TO MOISTURE INITIALLY AVAILABLE. A BETTER CHANCE FOR
PRECIPITATION WILL COME LATE SATURDAY NIGHT AND INTO SUNDAY POST
FRONTAL. INITIALLY MOST OF THE PRECIPITATION COULD BE RAIN AS ENOUGH
WARMER AIR LINGERS. WE COULD SEE IT TURN TO SOME SNOW POSSIBLY EARLY
SUNDAY AS ENOUGH COLD AIR MOVES IN.
- DRY EARLY NEXT WEEK WITH SEASONABLE TEMPERATURES
BEHIND THE COLD FRONT AND UPPER WAVE ON SUNDAY, WE WILL SEE A FAIRLY
STRONG CANADIAN RIDGE MOVE IN FOR AT LEAST MONDAY. SOME UNCERTAINTY
HAS CREPT IN WITH ADDITIONAL SHORT WAVES TRYING TO DROP IN AS EARLY
AS TUESDAY, AND MORE LIKELY WEDNESDAY. THIS PATTERN WILL KEEP TEMPS
IN THE SEASONABLE RANGE.
AVIATION /18Z TAFS THROUGH 18Z THURSDAY/
ISSUED AT 150 PM EDT WED MAR 18 2026
MAIN CONCERN THIS TAF PERIOD IS FREEZING DRIZZLE THIS AFTERNOON
AND FREEZING RAIN OVERNIGHT. THE MAIN SWATH OF FREEZING DRIZZLE
THIS AFTERNOON CONTINUES TO EXIT THE REGION TO THE EAST, THOUGH
SOME LINGERING -FZDZ CONTINUES ALONG THE LAKESHORE, AFFECTING MKG.
THAT WILL CONTINUE FOR THE NEXT FEW HOURS. MVFR CIGS WILL CONTINUE
THROUGH THE AFTERNOON, THOUGH THEY WILL SLOWLY IMPROVE AFTER 20Z.
MVFR CIGS SHOULD LIFT AROUND 00Z.
ANOTHER ROUND OF SHOWERS WILL MOVE IN OVERNIGHT, MAINLY BETWEEN
08Z AND 14Z. THERE IS A CHANCE THAT TEMPS COULD DROP DOWN BELOW
FREEZING, SO FREEZING RAIN IS A CONCERN AND HAVE PUT IN PROB30'S
AND PREVAILING IN AFFECTED TAF SITES. CHANCES FOR RAIN FADE AFTER
14Z, THOUGH THERE REMAINS SOME CHANCE BETWEEN 14Z TO 18Z,
ESPECIALLY FOR THE CENTRAL TAF SITES OF LAN AND JXN.
VFR CIGS WILL DROP TO MVFR OVERNIGHT, CORRESPONDING WITH THE
RAIN, AND PERIODS OF IFR ARE POSSIBLE BETWEEN 10Z AND 14Z. ANY IFR
SHOULD IMPROVE AFTER 14Z WITH MVFR CONTINUING THROUGH 18Z.
MARINE
ISSUED AT 256 PM EDT WED MAR 18 2026
WE WILL CANCEL THE SOUTHERN TWO MARINE ZONES A LITTLE EARLY WITH
THIS AFTERNOON'S PACKAGE. WINDS HAVE COME DOWN SUFFICIENTLY ALONG
THE ENTIRE NEARSHORE. NOW WE JUST HAVE TO WAIT FOR THE WAVES TO
FOLLOW SUIT IN THEIR TYPICAL LAGGING FASHION.
OUR NEXT MARINE HEADLINE WILL LIKELY BE A SMALL CRAFT ADVISORY
NEEDED BEGINNING DURING THE THURSDAY NIGHT-FRIDAY TIME FRAME. THAT
EVENT WILL BE A FLOW FROM THE SW ON THE FRONT END, AND THEN NW ON
THE BACK END.
HYDROLOGY
ISSUED AT 256 PM EDT WED MAR 18 2026
THIS FLOODING EVENT HAS JUST ABOUT PEAKED WITH THE FOUR SITES NEAR
OR ABOVE FLOOD STAGE HAVING CRESTED. WITH LIGHT AMOUNTS OF
PRECIPITATION EXPECTED OVER THE NEXT FEW DAYS, ADDITIONAL FLOODING
IS NOT EXPECTED.
GRR WATCHES/WARNINGS/ADVISORIES
MI...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 11 PM EDT THIS EVENING FOR LMZ844>849.
DISCUSSION...NJJ
AVIATION...CERU
MARINE...NJJ
HYDROLOGY...NJJ
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