579
FXUS63 KGRR 190701
AFDGRR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND RAPIDS MI
301 AM EDT THU MAR 19 2026
KEY MESSAGES
- POCKETS OF FREEZING RAIN THIS MORNING
- RAIN NORTH TONIGHT, LOW CHANCES FOR FREEZING RAIN
- WARMER SATURDAY WITH RAIN CHANGING TO SNOW SAT NIGHT-SUN
- DRY EARLY NEXT WEEK WITH SEASONABLE TEMPERATURES
DISCUSSION
ISSUED AT 301 AM EDT THU MAR 19 2026
- POCKETS OF FREEZING RAIN THIS MORNING
SATELLITE AND RADAR INDICATED AN AREA OF CONVECTIVE CELLS EXTENDING
FROM EASTERN WI INTO SOUTHWEST LOWER MI. THIS APPEARS TO BE
ASSOCIATED WITH AN UPPER PV MAX MOVING SOUTHEAST ACROSS NORTHERN
LOWER MI AT THIS TIME. IT'S POSSIBLE WE ARE SEEING THE BACK EDGE
OF PRECIPITATION OVER EASTERN WI, BUT THEN AGAIN, SATELLITE DOES
SHOW ANOTHER MORE SUBTLE UPPER PV MAX FARTHER UPSTREAM CROSSING
OVER EXTREME WESTERN LAKE SUPERIOR AS IT MOVES SOUTHEAST. AS NOTED
BEFORE, THIS IS A COMPLICATED SETUP. WEAKLY FORCED AND LARGELY
ELEVATED POPCORN CONVECTION LIKE WE'RE SEEING HERE IS SOMETHING
THAT CONVECTION ALLOWING MODELS ARE NOT USUALLY GOING TO HANDLE
WELL, IF AT ALL.
ALTHOUGH RADAR REFLECTIVITIES ARE OCCASIONALLY EXCEEDING 40 DBZ
WITH THESE CELLS, SURFACE PRECIPITATION AMOUNTS SO FAR HAVE BEEN
LIGHT, ON THE ORDER OF A TRACE TO A HUNDREDTH OF AN INCH. THIS IS
NOT SURPRISING GIVEN THAT CLOUD BASES ARE GENERALLY 8000 FT AGL OR
GREATER, ALLOWING SUBSTANTIAL SUB-CLOUD EVAPORATION TO OCCUR. RWIS
DATA SHOWS ROAD TEMPERATURES HAVE DROPPED BELOW FREEZING ACROSS
OF ALL OF OUR CWA EXCEPT FOR NEAR THE I-94 CORRIDOR. WE EXPECT
TEMPERATURES THERE TO DROP BELOW FREEZING AS WELL.
THIS IS A FORECAST WITH VERY LIMITED CERTAINTY BUT SUBSTANTIAL
POTENTIAL RISK WITH RESPECT TO THE MORNING COMMUTE. QUESTIONS
REMAIN CONCERNING EXACTLY HOW MUCH PRECIPITATION WILL FALL EARLY
THIS MORNING. A TRACE COULD BE NON-IMPACTFUL, WHEREAS EVEN A
HUNDREDTH COULD BRING VERY SLIPPERY CONDITIONS. GIVEN THE LIMITED
CERTAINTY, WILL BE ISSUING A SPECIAL WEATHER STATEMENT LATER THIS
MORNING INSTEAD OF AN ADVISORY. WE EXPECT SPOTTY ICING CONDITIONS
THIS MORNING, WHICH CAN ACTUALLY BE MORE DANGEROUS WHEN TRAVELING,
ESPECIALLY AT HIGHWAY SPEEDS.
AIR TEMPERATURES ARE EXPECTED TO WARM RATHER QUICKLY AFTER
SUNRISE. ROAD TEMPERATURES WILL OF COURSE LAG THIS A BIT, BUT WE
NONETHELESS EXPECT ANY SLIPPERY TRAVEL CONDITIONS TO BE GREATLY
REDUCED IF NOT ELIMINATED BEFORE 10 AM FOR MOST AREAS.
- RAIN NORTH TONIGHT, LOW CHANCES FOR FREEZING RAIN
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. CURRENT INDICATIONS ARE THAT
TEMPERATURES WILL BE WARM ENOUGH FOR THIS TO FALL AS RAIN INSTEAD
OF FREEZING RAIN. THIS WOULD BE MOST LIKELY TO OCCUR OVER OSCEOLA
AND CLARE COUNTIES WITH AMOUNTS IN THE 0.01 TO 0.10 INCH RANGE.
THERE IS OBVIOUS CONCERN IN THIS AREA ABOUT ANY ADDITIONAL
FREEZING RAIN THAT MIGHT OCCUR GIVEN WHAT HAS ALREADY HAPPENED
THERE. AT THIS POINT, PROBABILITIES FOR EVEN 0.01" OF FREEZING
RAIN ARE IN THE 10-20 PERCENT RANGE FOR NORTHERN CLARE COUNTY. WE
WILL BE MONITORING NEW PROBABILISTIC GUIDANCE AS IT BECOMES
AVAILABLE TO SEE IF TRENDS CHANGE.
- 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 /06Z TAFS THROUGH 06Z FRIDAY/
ISSUED AT 125 AM EDT THU MAR 19 2026
MADE VERY FEW CHANGES TO THE INHERITED TAFS FOR THIS UPDATE. WE
CONTINUE TO EXPECT CHANCES FOR FZRA THIS MORNING. RADAR INDICATES
A SCATTERED COVERAGE OF CONVECTIVE CELLS APPROACHING FROM THE
NORTHWEST. THIS SHOULD RESULT IN SPOTTY AND EPISODIC ICE
ACCUMULATIONS. HENCE, WE BELIEVE THAT PROB30 CONTINUES TO BE THE
BEST WAY TO REPRESENT THIS THREAT.
AS NOTED PREVIOUSLY, WE DO EXPECT A PERIOD OF IFR CEILINGS AS
WELL FOR GRR, AZO AND BTL. THE GOOD NEWS IS THAT WARMING
TEMPERATURES LATE THIS MORNING AND INCREASING CLOUD BASES WILL
ELIMINATE THE THREATS OF FREEZING PRECIPITATION AND CEILING
RESTRICTIONS BY AFTERNOON.
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...NONE.
DISCUSSION...TJT/NJJ
AVIATION...TJT
HYDROLOGY...NJJ
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