116
FXUS63 KGRR 310528
AFDGRR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND RAPIDS MI
1228 AM EST FRI JAN 31 2025
KEY MESSAGES
- MAINLY RAIN EVENT TONIGHT INTO FRIDAY EVENING
- RAIN AND SNOW CHANCES ON SUNDAY
- MID NEXT WEEK SYSTEM MAY BRING MIX TO THE AREA
UPDATE
ISSUED AT 912 PM EST THU JAN 30 2025
KGRR/RGNL RADAR TRENDS AS OF 02Z SHOW RAIN SHOWERS BEGINNING TO
MOVE INTO OUR EXTREME SW FCST AREA. EXTRAPOLATION OF RADAR TRENDS
CORROBORATED WITH A CONSENSUS OF LATEST CAMS SUGGESTS THAT THESE
SHOWERS WILL CONTINUE TO MOVE ENE TO GRADUALLY AFFECT OUR SOUTHERN
FCST AREA OVERNIGHT. OUR GOING FORECAST FOR TONIGHT HAS THIS
HANDLED WELL AND NO APPRECIABLE FCST CHANGES ARE NEEDED.
DISCUSSION
ISSUED AT 344 PM EST THU JAN 30 2025
- MAINLY RAIN EVENT TONIGHT INTO FRIDAY EVENING
A LOW IN MISSOURI THIS AFTERNOON WILL MOVE EASTWARD OVER THE NEXT
24 HOURS TRACKING THROUGH NORTHERN IL, IN AND OH. BY FRIDAY
EVENING THE LOW WILL HAVE MOVED INTO OH. PRECIPITATION WILL COME
IN A COUPLE OF DIFFERENT WAVES, ONE THIS EVENING AND ANOTHER
DURING THE DAY ON FRIDAY. BEST CHANCES FOR PRECIPITATION WITH THIS
EVENING WILL OCCUR OVER SOUTHERN LOWER MICHIGAN DOWN TOWARDS I-94
WITH LIMITED CHANCES NORTH OF M-20.
THE UPPER WAVE WILL BE WEAKENING AS IT MAKES ITS APPROACH TOWARDS
AND PASS THROUGH THE SOUTHERN GREAT LAKES. THE CLOSEST APPROACH TO
THE AREA WILL BE ACROSS NORTHERN INDIANA FRIDAY AFTERNOON WITH A
MEAN LOW DEPTH OF AROUND 1003MB IN THE OPERATIONAL MODELS. NOT A
SIGNIFICANT LOW BY WINTER STANDARDS, BUT IT WILL FORCE A FAIR
AMOUNT OF PRECIPITATION TO THE NORTH OF THE LOW AND ITS
ASSOCIATED WARM FRONT. THE 850MB WARM FRONT SETS UP ACROSS
SOUTHERN LOWER MICHIGAN NOT FAR FROM I-94, WHICH IS WHY WE SEE THE
HIGHEST PRECIPITATION TOTALS DOWN THERE ON THE ORDER OF 0.50 TO
0.75 OF AN INCH.
PRECIPITATION TYPE ISSUES ARE NOT REALLY EXPECTED ACROSS THE FAR
SOUTH AS THIS WILL MAINLY BE A RAIN EVENT. WE ARE NOT ANTICIPATING
ISSUES IN OTHER AREAS EITHER AS TEMPERATURES WILL BE VERY MARGINAL
IN THE LOWER TO MIDDLE 30S ACROSS THE I-96 AND M-57 CORRIDORS.
THERE COULD BE A LITTLE BIT OF FREEZING RAIN ON THE NORTHERN
FRINGES OF THE PRECIPITATION SHIELD FRIDAY MORNING NEAR M-57. AT
THIS POINT MODEL CONSENSUS IS NOT PAINTING MUCH IN THE WAY OF ICE
AND WE AGREE WITH THAT. THE NAM IS AN OUTLIER IN PUTTING DOWN MORE
SIGNIFICANT ICE. TEMPERATURES WELL INTO THE 40S TODAY DOES NOT
LEND A LOT OF CREDENCE TO IMPENDING ICE. AS THE SYSTEM LIFTS OUT
TO THE EAST FRIDAY EVENING, THERE WILL BE SOME SNOW THAT MIXES IN,
BUT AGAIN NOT ANTICIPATING MUCH ACCUMULATION. SHOULD BE INCH OR
LESS AMOUNTS. MOST AREAS WILL SEE LITTLE TO NO SNOW.
- RAIN AND SNOW CHANCES ON SUNDAY
A WEAK WAVE IN ZONAL FLOW WILL BRING RAIN AND SNOW CHANCES TO THE
AREA CENTERED ON SUNDAY, BUT THERE ARE MODEL DIFFERENCES WITH THIS
WEAK WAVE. ESSENTIALLY THIS IS A WEAK CLIPPER SYSTEM THAT WILL
PASS MAINLY OFF TO OUR NORTH. THE FORECAST REMAINS THE SAME IN
THAT WE COULD SEE AN INCH OR TWO OF SNOW ACROSS CENTRAL LOWER
MICHIGAN ON SUNDAY.
- MID NEXT WEEK SYSTEM MAY BRING MIX TO THE AREA
WE ARE STILL LOOKING AT A SYSTEM FOR MID NEXT WEEK IN CONTINUED
ZONAL FLOW. AT THIS POINT A LIGHT MIX OF PRECIPITATION IS OUR
FORECAST WITH MORE RAIN IN THE SOUTH AND SNOW ACROSS CENTRAL LOWER
MICHIGAN. WE HAVE 40-60 PCT POPS IN THE FORECAST FOR NOW, BUT
THERE IS A FAIR AMOUNT OF MODEL DISPARITY.
AVIATION /06Z TAFS THROUGH 06Z SATURDAY/
ISSUED AT 1228 AM EST FRI JAN 31 2025
IFR AND LIFR CEILINGS WILL GRADUALLY WORK IN FROM THE SOUTH ALONG
WITH THE ONGOING RAIN FROM AZO TO JXN. VISIBILITIES WITH THE RAIN
ARE RANGING AROUND 2 TO 5 SM CURRENTLY WITH LOWER VISIBILITIES
POSSIBLE DURING THE DAY MAINLY FROM AZO TO LAN AND SOUTH. FRIDAY
AFTERNOON SNOW MAY MIX IN WITH THE RAIN BEFORE ENDING FRIDAY
EVENING WITH CEILINGS GRADUALLY IMPROVING TO VFR FRIDAY NIGHT.
HYDROLOGY
ISSUED AT 310 PM EST THU JAN 30 2025
WHILE THE UPCOMING RAIN AMOUNTS WILL NOT BE ENOUGH ON THEIR OWN TO
CAUSE ANY FLOODING, WE MUST ALSO THINK ABOUT THE RISK OF RIVER ICE
BREAKUP/JAMS. THE GOOD NEWS IS THAT OUR RIVER ICE IS CURRENTLY IN A
STABLE PLACE, AND HAS ACTUALLY BEEN SLOWLY WEAKENING (IN A GOOD WAY)
SINCE WE CAME OUT OF THE DEEP FREEZE LAST WEEK. IT WOULD PROBABLY
TAKE RISES OF 3 FEET OR MORE ON MOST OF OUR RIVERS TO FORCE THE ICE
TO BREAKUP AND MOVE (AND POTENTIALLY FORM ICE JAMS), AND BASED ON
0.5 TO 0.75" RAIN AMOUNTS EXPECTED ALONG AND SOUTH OF I-96, THE MOST
LIKELY OUTCOME HERE IS THAT WE SEE RISES MORE IN THE 1 TO 2 FOOT
RANGE, WHICH WE DO NOT CURRENTLY THINK WILL BE ENOUGH TO FORCE MUCH
ICE TO MOVE OVER THE NEXT FEW DAYS. THAT SAID, NOTHING'S IMPOSSIBLE
WHEN IT COMES TO RIVER ICE, SO WHILE WE ARE CURRENTLY NOT EXPECTING
ANY ISSUES, WE ALWAYS ENCOURAGE PEOPLE LIVING ALONG ICE-COVERED
RIVERS TO PAY EXTRA ATTENTION DURING/AFTER ALL WINTERTIME RAIN
EVENTS, AS CONDITIONS CAN CHANGE QUICKLY.
GRR WATCHES/WARNINGS/ADVISORIES
MI...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 1 AM EST EARLY THIS MORNING FOR
LMZ844>849.
UPDATE...LAURENS
DISCUSSION...DUKE
AVIATION...RAH
HYDROLOGY...AMD
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