721
FXUS63 KGRR 051044
AFDGRR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND RAPIDS MI
644 AM EDT SUN APR 5 2026
KEY MESSAGES
- COLD AND UNSETTLED TODAY THROUGH MONDAY
- MODERATING TEMPERATURES AND QUIET MID-WEEK
- MORE CHANCES FOR RAIN LATE WEEK
DISCUSSION
ISSUED AT 302 AM EDT SUN APR 5 2026
- COLD AND UNSETTLED TODAY THROUGH MONDAY
THE WARMER AND WET CONDITIONS MULTIPLE TIMES OVER THE LAST WEEK ARE
A DISTANT MEMORY ALREADY FOR THE AREA, AS WE HAVE MUCH COLDER AIR
HAVING ARRIVED AND DRY WEATHER THIS MORNING COMPARED TO THE
DOWNPOURS FROM YESTERDAY MORNING. WE HAVE SEEN THE UPPER FLOW FLIP
FROM THE SSW YESTERDAY, TO WNW THIS MORNING. THE IS REMINISCENT OF
THE PATTERN FROM MUCH OF THE WINTER.
WE HAVE THE UPPER CYCLONIC FLOW NOW OVER THE AREA THROUGH MONDAY
NIGHT. THIS MEANS WE HAVE SHORT WAVE ACTIVITY THAT WILL BRING SOME
SMALL CHANCES OF PRECIPITATION TO THE AREA. THE FIRST ONE OF THESE
WILL COME THROUGH THIS MORNING. EVEN WITH THE UPPER JET BEING SOUTH
OF THE AREA, THE AIR IS NOT COLD ENOUGH FOR A MEANINGFUL LAKE
CONTRIBUTION. IN ADDITION, THERE IS VERY LITTLE MOISTURE IN PLACE
AFTER THE FRONT YESTERDAY SWEPT IT OUT OF THE AREA. IT WILL BE COLD
ENOUGH THOUGH THAT MUCH OF THE SHOWER ACTIVITY WILL BE SNOW SHOWERS.
THE NEXT SHORT WAVE IN THE SERIES ARRIVES TOWARD 06Z MONDAY. ONCE
AGAIN MOISTURE WILL BE LACKING WITH THIS SHORT WAVE. THEN,
TEMPERATURES MODERATE A BIT, AND TEMPERATURE PROFILES WOULD SUPPORT
MORE RAIN THAN SNOW EVEN BEING AT NIGHT. THIS CHANGES FOR THE FINAL
SHORT WAVE THAT COMES THROUGH LATER MONDAY, AS WE WILL SEE -13C
APPROACH THE FORECAST AREA AT 850 MB. THE THING THAT IS SAVING THE
AREA FROM ACCUMULATING SNOW IS THE UPPER FLOW IS GOING ANTI-
CYCLONIC, WHICH LIMITS THE SNOW SHOWERS ON MONDAY. THERE COULD BE
SOME NICE QUICK BURSTS OF SNOW SHOWERS ON MONDAY WITH THE FINAL
WAVE.
- MODERATING TEMPERATURES AND QUIET MID-WEEK
TUESDAY AND WEDNESDAY ARE LOOKING LIKE THE QUIETEST PERIODS OF THE
WEEK. WE SEE A FAIRLY STRONG SFC RIDGE BUILD OVER THE AREA ON
TUESDAY IN THE WAVE OF THE LATE MONDAY SYSTEM. THIS RIDGE IS
FORECAST TO BE UP AROUND 1036 MB AS IT BUILDS TOWARD THE AREA. IT
WILL HOLD JUST ENOUGH TO KEEP THE PRECIPITATION WITH THE NEXT SYSTEM
JUST WEST OF THE AREA THROUGH WEDNESDAY.
WE WILL SEE A SIGNIFICANT DIFFERENCE IN THE TEMPERATURES FROM
TUESDAY TO WEDNESDAY. 850 MB TEMPS GO FROM AROUND -11C ON TUESDAY,
TO AROUND +7C ON WEDNESDAY. IT WILL TAKE A LITTLE BIT TO ADVECT THAT
WARM WEATHER IN THE AREA, BUT IT SHOULD ARRIVE BY LATER WEDNESDAY
AFTERNOON.
- MORE CHANCES FOR RAIN LATE WEEK
THE SFC RIDGE MOVES OUT BY THURSDAY, AND ALLOWS THE NEXT SYSTEM TO
DROP IN FROM THE WNW ON THURSDAY. THE NEXT SYSTEM WILL BE COMING IN
FROM THE NW, BUT WILL HAVE QUITE A SOUTHERLY FLOW AHEAD OF IT. THIS
FLOW WILL BE ABLE TO DRAW MOISTURE NORTHWARD FROM THE GULF. THIS
WILL BRING THE AREA A CHANCE OF RAIN ON THURSDAY.
THE FRONT DROPS SOUTH OF THE AREA BY FRIDAY, AND GETS HUNG UP JUST
SOUTH OF THE MI/IN/OH STATE BORDER. IT WILL THEN BECOME STATIONARY
BRIEFLY, WAITING FOR THE NEXT WAVE TO RIDE ALONG IT, AND POTENTIALLY
BRING MORE RAIN TO THE AREA.
AVIATION /12Z TAFS THROUGH 12Z MONDAY/
ISSUED AT 644 AM EDT SUN APR 5 2026
WE ARE STARTING TO SEE MVFR CEILINGS FLOAT BACK OVER THE
TERMINALS AFTER A FEW HOUR BREAK FROM THE LOWER CLOUDS. A FEW
FLURRIES OR LIGHT SNOW SHOWERS WILL BECOME POSSIBLE FOR A FEW
HOURS THIS MORNING, BEFORE MOVING OUT TOWARD NOON. CEILINGS WILL
EVENTUALLY LIFT TO VFR AGAIN BY MID-LATE AFTERNOON. WE COULD EVEN
SEE SKIES PARTIALLY CLEAR OUT FOR A FEW HOURS LATE THIS AFTERNOON
AND EVENING.
WE WILL SEE ANOTHER BATCH OF SHOWERS MOVE IN THEN AFTER 00Z
TONIGHT. CEILINGS WILL BE HIGHER AT FIRST, WITH LITTLE TO NO
RESTRICTION TO VISIBILITY. THEN LOW LEVEL MOISTURE RETURNS, AND
WE WILL SEE ALL SITES GO DOWN TO MVFR. THE SHOWERS SHOULD BE
MAINLY RAIN THIS TIME WITH THE COLUMN HAVING WARMED A BIT COMPARED
TO TODAY.
MARINE
ISSUED AT 302 AM EDT SUN APR 5 2026
WE WILL BE HOLDING ON TO THE SMALL CRAFT ADVISORY AS IS THIS
MORNING, THROUGH THIS EVENING. WINDS COULD BE CLOSE TO GALES AT
TIMES THROUGH THE NEXT FEW OURS, BUT THIS IS MORE MARGINAL THAN LAST
EVENING WAS. THE ENDING TIME OF THE ADVISORY LINES UP WELL
WITH THE LATEST WAVE FORECAST.
WE WILL SEE A BRIEF BREAK THEN TONIGHT, BEFORE WINDS INCREASE ONCE
AGAIN, LIKELY NEEDING ANOTHER HEADLINE FOR MONDAY, AND MAYBE EVEN A
GALE.
HYDROLOGY
ISSUED AT 136 PM EDT SAT APR 4 2026
RAINFALL OF 1-3 INCHES ACROSS SOUTHWEST MICHIGAN IN THE PAST 24
HOURS ADDS TO THE PREVIOUS ACCUMULATIONS FOR A ROUGHLY 4-6 INCH
RAINFALL TOTAL OVER THE LAST WEEK.
WITH THE HEAVIEST RAIN ACROSS THE GRAND RIVER BASIN, THIS WILL LEAD
TO RIVER FLOODING OVER THE NEXT SEVERAL DAYS. RIVER FLOOD WARNINGS
HAVE BEEN ISSUED FOR THE GRAND RIVER AND ITS TRIBUTARIES IN LANSING,
THE PORTAGE RIVER AT VICKSBURG, THE MUSKEGON RIVER AT NEWAYGO AND
BRIDGETON, THE GRAND RIVER AT COMSTOCK PARK, AND THE THORNAPPLE
RIVER AT CALEDONIA AND HASTINGS. FOR THE MOST PART RIVERS WILL PEAK
AT MINOR FLOOD STAGE, WITH THE EXCEPTION OF COMSTOCK PARK AND
ROBINSON TOWNSHIP (THE LATTER OF WHICH IS IN A WATCH) WHERE MODERATE
FLOODING IS FORECAST.
THE HIGH WATER WILL WORK ITS WAY THROUGH GRAND RIVER SYSTEM OVER THE
NEXT SEVERAL DAYS, WITH FLOODING FORECAST ALONG THE GRAND RIVER FROM
IONIA TO GRAND RAPIDS, TO ROBINSON TOWNSHIP. GIVEN FLOODING IS 48-96
HOURS AWAY FOR THESE AREAS, RIVER FLOOD WATCHES HAVE BEEN ISSUED,
WITH THE POTENTIAL FOR WARNINGS AS WE GET CLOSER TO THE EVENT.
NUMEROUS OTHER RIVERS WILL REACH ACTION STAGE OVER THE COMING DAYS,
SOME LIKE THE MUSKEGON RIVER AT EVART GETTING CLOSE TO MINOR FLOOD
STAGE. PEOPLE NEAR AREA RIVERS SHOULD MONITOR THE LATEST NATIONAL
WEATHER SERVICE FORECASTS.
GRR WATCHES/WARNINGS/ADVISORIES
MI...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 8 PM EDT THIS EVENING FOR LMZ844>849.
DISCUSSION...NJJ
AVIATION...NJJ
MARINE...NJJ
HYDROLOGY...THOMAS
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