436
FXUS63 KGRR 080723
AFDGRR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND RAPIDS MI
323 AM EDT SUN JUN 8 2025
KEY MESSAGES
- UPPER LOW BRINGS SOME RAIN NEXT COUPLE DAYS
- LOW CONFIDENCE IN RAIN/CONVECTION LATE WEEK
DISCUSSION
ISSUED AT 323 AM EDT SUN JUN 8 2025
- UPPER LOW BRINGS SOME RAIN NEXT COUPLE DAYS
LOW PRESSURE TRACKING ACROSS THE OHIO VALLEY WILL BRING LIGHT RAIN
TO THE FAR SOUTHERN ZONES TODAY, WHILE THE REST OF THE FORECAST
AREA SEES RAIN CHANCES INCREASE LATE THIS AFTERNOON. A LINE OF
SHOWERS AND A FEW THUNDERSTORMS CAN BE EXPECTED ALONG A COLD FRONT
IN ADVANCE OF A VIGOROUS UPPER LOW MOVING ACROSS THE GREAT LAKES
REGION.
THUNDER POTENTIAL IS LIMITED BY MARGINAL INSTABILITY BUT WIND
PROFILES SHOW 40 KNOTS OF DEEP LAYER SHEAR, SO THE NARROW NCFR
CURRENTLY SEEN ACROSS NORTHWEST WISCONSIN COULD HOLD TOGETHER AND
BE BUILDING SOUTH TODAY, THEN AND CROSSING THE LAKE INTO WESTERN
LOWER MICHIGAN BY LATE AFTERNOON OR EARLY EVENING AS SUGGESTED BY
THE HI-RES ARW AND HRRR.
THE CORE REGION OF THE UPPER LOW MOVES IN BY MONDAY AFTERNOON AND
COMBINES WITH DEEPER MOISTURE AND STEEPENING LAPSE RATES TO BRING
A DIURNAL ENHANCEMENT OF SHOWERS AND THUNDERSTORMS IN THE
AFTERNOON AND EVENING. THE LOW MOVES OUT LATE TUESDAY WITH FAIR
WEATHER RETURNING FOR WEDNESDAY.
- LOW CONFIDENCE IN RAIN/CONVECTION LATE WEEK
LONGER RANGE MODEL GUIDANCE SHOWS POTENTIAL FOR MCS DEVELOPMENT
THURSDAY INTO FRIDAY ALONG A BAROCLINIC ZONE/STALLED FRONT IN THE
VICINITY OF IOWA OR SOUTHERN MINNESOTA THAT PROPAGATES EAST AND
POTENTIALLY BRINGS RAIN AND CONVECTIVE STORMS INTO LOWER MICHIGAN.
THERE IS CONSIDERABLE SPREAD IN WHERE THIS FRONT SETS UP AND WHERE
THE MCS TRACKS, SO FORECAST CONFIDENCE IS LOW THE CURRENT NBM
POPS/TIMING APPEARS TO BE A GOOD COMPROMISE OF MODEL DIFFERENCES.
AVIATION /06Z TAFS THROUGH 06Z MONDAY/
ISSUED AT 128 AM EDT SUN JUN 8 2025
VFR CONDITIONS EXPECTED TO CONTINUE INTO SUNDAY AFTERNOON AND
EVENING. THERE COULD BE SOME AREAS OF MVFR IN PATCHY SHALLOW FOG
OVERNIGHT AS WELL AS A FEW RAIN SHOWERS NEAR AZO AND JXN. THERE IS
A LOW CHANCE OF THUNDERSTORMS LATE SUNDAY AFTERNOON AND EVENING
BUT THIS WAS LEFT OUT OF THE FORECAST SINCE COVERAGE IS EXPECTED
TO BE LOW.
MARINE
ISSUED AT 128 AM EDT SUN JUN 8 2025
WINDS AND WAVES ARE EXPECTED TO BE RELATIVELY CALM THROUGH THE
MIDDLE OF NEXT WEEK WITH WINDS LESS THAN 20 KNOTS AND WAVES 3 FEET
OR LESS.
GRR WATCHES/WARNINGS/ADVISORIES
MI...NONE.
MARINE...NONE.
DISCUSSION...OSTUNO
AVIATION...OSTUNO
MARINE...OSTUNO
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