392
FXUS63 KGRR 191911
AFDGRR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND RAPIDS MI
311 PM EDT SUN OCT 19 2025
KEY MESSAGES
- RAIN ENDING AND WINDS DIMINISHING TONIGHT
- ANOTHER ROUND OF RAIN AND WIND MONDAY NIGHT INTO TUESDAY
- COOL AND UNSETTLED WEATHER THROUGH THE END OF THE WEEK
DISCUSSION
ISSUED AT 311 PM EDT SUN OCT 19 2025
- RAIN ENDING AND WINDS DIMINISHING TONIGHT
THE HEAVIER WIDESPREAD RAIN FROM LAST NIGHT HAS NOW TRANSITIONED TO
MORE LIGHTER BANDS OF RAIN THIS AFTERNOON AS THE DEEP MOISTURE AHEAD
OF THE SYSTEM HAS MOVED OUT, AS WE ARE SEEING THE PARENT UPPER
TROUGH APPROACHING. THE UPPER TROUGH WILL CONTINUE TO STEADILY MOVE
EAST AS THE NEXT STRONG SYSTEM IS KEEPING THE UPPER AIR PATTERN
PROGRESSIVE FOR THE TIME BEING. WE SHOULD SEE THE SKIES CLEAR OUT
AFTER DARK AS WE SEE STRONGER SUBSIDENCE BUILD IN WITH THE UPPER
RIDGING.
- ANOTHER ROUND OF RAIN AND WIND MONDAY NIGHT INTO TUESDAY
THIS CLEARING WILL BE SHORT LIVED, ONLY LASTING THROUGH THE DAYLIGHT
HOURS ON MONDAY. THIS WILL BE BECAUSE THE LEADING EDGE OF THE NEXT
UPPER TROUGH WILL BE APPROACHING THE LAKESHORE JUST AFTER 00Z
TUESDAY. THE WINDS AT THE SFC FROM THE SOUTH WILL RESPOND EVEN
EARLIER AS THE STRONG GRADIENT MOVES IN DURING THE AFTERNOON AND
EVENING HOURS AHEAD OF THE SFC LOW.
RAIN WILL SPREAD ACROSS THE AREA LATE MONDAY EVENING INTO THE EARLY
HOURS ON TUESDAY CLOSE TO THE OCCLUDED FRONT THAT WILL BE PASSING
THROUGH. THIS FRONT WILL BE LACKING MOISTURE AS IT APPROACHES, AND
WILL FINALLY BE ABLE TO DRAW SOME GULF MOISTURE AS IT MOVES THROUGH
EARLY TUESDAY PRIOR TO DAYBREAK. INSTABILITY PARAMETERS ARE PROBABLY
JUST A TAD TOO STABLE AHEAD OF THE FRONT TO GENERATE THUNDER. THERE
IS A CHANCE THOUGH THAT THE LAKE COULD HELP WITH THE INSTABILITY.
ONCE THE FRONT MOVES THROUGH BY LATE TUESDAY, IT LOOKS LIKE WE WILL
SEE LAKE EFFECT RAIN SHOWERS START TO GENERATE. THE COLD POOL ALOFT
WILL MOVE OVERHEAD, BRINGING 850 MB TEMPERATURES DOWN TO AROUND )C
OR EVEN A TAD BELOW 0C. THESE TEMPERATURES COMING IN OVER THE 16-17C
WATER WILL CREATE PLENTY OF LAKE EFFECT INSTABILITY. LAKE INDUCED
EQUILIBRIUM LEVELS/INVERSION HEIGHTS WILL RISE QUITE HIGH, AND WELL
UP INTO THE ICE LAYER TO GENERATE STORMS. COMBINE THAT WITH STRONG
SHORT WAVE ACTIVITY, AND THE RADAR WILL BE LIT UP WELL ALONG THE
LAKESHORE.
- COOL AND UNSETTLED WEATHER THROUGH THE END OF THE WEEK
THE UPPER LOW AT THE CENTER OF THE MON NIGHT/TUE SYSTEM WILL HELP TO
CLOSE OFF AN UPPER LOW CENTERED JUST NE OF THE AREA, AND KEEP UPPER
CYCLONIC AND COLD TEMPS ALOFT OVERHEAD. SHORT WAVE ACTIVITY WILL
CONTINUE TO RIDE IN FROM THE NW ON THE BACKSIDE OF THE UPPER LOW
POTENTIALLY THROUGH FRIDAY. THIS WILL ALLOW FOR BELOW AVERAGE
TEMPERATURES, AND PERIODIC RAIN SHOWER CHANCES THROUGH FRIDAY.
THERE IS HOPE THAT WE WILL SEE THE UPPER LOW ROTATE OUT OF THE AREA
NO LATER THAN SATURDAY AND CONTINUE INTO SUNDAY.DDS
AVIATION /18Z TAFS THROUGH 18Z MONDAY/
ISSUED AT 145 PM EDT SUN OCT 19 2025
MVFR TO IFR CONDITIONS WILL CONTINUE AS RAIN SHIFTS EAST THROUGH
THE AREA EXITING AROUND 21Z-03Z FROM WEST TO EAST. DURING THIS
TIME CEILINGS WILL LIFT AND CLEAR. SOME FEW TO SCT CLOUDS AROUND
4000 TO 6000 FEET MAY LINGER INTO MONDAY MORNING.
NORTHWEST WINDS GUSTING 25 TO 35 KNOTS WILL CONTINUE THROUGH THE
AFTERNOON ON THE BACKSIDE OF THE LOW AND WEAKEN AFTER 00Z. A
PERIOD OF LOW LEVEL WIND SHEAR IS POSSIBLE FOR GRR, AZO, AND BTL
THROUGH 9Z AS WINDS BECOME LIGHT ENOUGH AT THE SURFACE WITH 30
KNOTS SUSTAINED AROUND 2000 FEET. WINDS WILL THEN BE LIGHT AND
FROM THE SOUTHWEST INITIALLY MONDAY BEFORE BUILDING INTO THE
AFTERNOON.
MARINE
ISSUED AT 311 PM EDT SUN OCT 19 2025
NORTHWEST GALES TO 40 KNOTS CONTINUE THIS AFTERNOON WITH WAVE
HEIGHTS 9 TO 12 FEET. WINDS WILL GRADUALLY WEAKEN BELOW GALES THIS
EVENING WITH THE POTENTIAL OF THE GALE WARNING EXPIRING EARLIER. A
SMALL CRAFT ADVISORY WILL THEN BE NEEDED AS WAVES REMAIN HIGH AND
GUSTY SOUTHERLY WINDS RETURN WITH THE POTENTIAL FOR GALES MONDAY
NIGHT AHEAD OF OUR NEXT LOW PRESSURE SYSTEM. THERE IS A HIGHER
PROBABILITY FOR GALES HOWEVER TUESDAY AFTERNOON INTO WEDNESDAY ON
THE BACKSIDE OF THE LOW WITH WINDS TURNING FROM THE SOUTHWEST TO THE
NORTHWEST. GALES TO 40 KNOTS ARE LIKELY DURING THIS PERIOD WITH A
LOW CHANCE FOR STORM FORCE GUSTS. HIGH WAVES AND GUSTY WINDS LINGER
INTO THURSDAY WITH WATERS FINALLY BECOMING CALMER BY THE END OF THE
WEEK.
HYDROLOGY
ISSUED AT 311 PM EDT SUN OCT 19 2025
THE AREA GENERALLY SAW BETWEEN 1 AND 3 INCHES OF RAIN AS EXPECTED
FOR THE HEART OF THIS EVENT THAT IS NOW WINDING DOWN. THERE MAY HAVE
BEEN SOME LOCALIZED HEAVY AMOUNTS. WE HAVE NOT RECEIVED ANY IMPACTS
FROM THE RAIN.
THIS RAIN WAS GENERALLY VERY GOOD FOR THE ONGOING DROUGHT SITUATION
ACROSS THE AREA. THE RIVER AND STREAM LEVELS HAVE RESPONDED TO THE
RAIN, BUT THE RISES ARE LIKELY MUTED A BIT DUE TO THE VERY DRY DEEP
GROUND THAT LIKELY SOAKED UP A LOT OF THE RAIN, ESPECIALLY SINCE IT
WAS SPREAD OUT OVER 24-36 HOURS.
ADDITIONAL RAIN THIS WEEK DOES NOT LOOK HEAVY, SO THE RIVERS AND
STREAMS SHOULD CONTINUE TO BEHAVE.
GRR WATCHES/WARNINGS/ADVISORIES
MI...NONE.
MARINE...GALE WARNING UNTIL 11 PM EDT THIS EVENING FOR LMZ844>849.
DISCUSSION...NJJ
AVIATION...RAH
MARINE...RAH
HYDROLOGY...NJJ
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