637
FXUS63 KGRR 311658
AFDGRR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND RAPIDS MI
1258 PM EDT MON MAR 31 2025
KEY MESSAGES
- WINTRY MIX LIKELY TUESDAY NIGHT
- SEVERE WEATHER POSSIBLE WEDNESDAY
- CHANCE OF RAIN SHOWERS THIS WEEKEND
UPDATE
ISSUED AT 1211 PM EDT MON MAR 31 2025
NORTHWEST FLOW COLD AIR ADVECTION IS OCCURRING IN THE WAKE OF THE
LOW PRESSURE SYSTEM THAT BROUGHT US ACTIVE WEATHER YESTERDAY.
MOSTLY CLOUDY SKIES PREVAIL AT THIS TIME ACROSS THE AREA, BUT
RIDGING BUILDING IN THIS AFTERNOON AND EVENING WILL GRADUALLY
ERODE CLOUD COVER AS WE HEAD THROUGH THE LATE AFTERNOON AND
ESPECIALLY THIS EVENING. NORMAL HIGHS TODAY ARE AROUND 50 AND WITH
THE COLD AIR FLOWING IN ON NORTHERLY WINDS WE WILL TOP OUT 10-15
DEGREES BELOW NORMAL. HIGHS WILL BE IN THE MIDDLE 30S TO AROUND
40.
DISCUSSION
ISSUED AT 347 AM EDT MON MAR 31 2025
- WINTRY MIX LIKELY TUESDAY NIGHT
AFTER DRY CONDITIONS THROUGH TUESDAY EVENING, PRECIPITATION RETURNS
TUESDAY NIGHT AS A STRONG LOW PRESSURE SYSTEM MOVES INTO THE REGION.
THIS SYSTEM IS THE PRIMARY FORECAST CONCERN FOR THE SEVEN DAY
WINDOW. THERMAL PROFILES SUGGEST PRECIPITATION STARTING AS ALL SNOW,
POSSIBLY MIXING WITH RAIN AT ONSET NEAR I94, CHANGING OVER TO RAIN
BY DAYBREAK SOUTH OF I96. NORTH OF I96 WHERE SURFACE COLDER AIR
HOLDS ON A BIT LONGER, ACCUMULATING SNOW AND FREEZING RAIN LOOK
LIKELY, LINGERING LONGEST ACROSS THE HIGHER TERRAIN OF CENTRAL
LOWER. AMOUNTS WILL NEED TO BE FINE-TUNED IN THE COMING PACKAGES BUT
TRAVEL IMPACTS ARE POSSIBLE, ESPECIALLY IF FREEZING RAIN OCCURS.
- SEVERE WEATHER POSSIBLE WEDNESDAY
SUBSTANTIAL ADVECTION OF WARM AND MOIST AIR OCCURS GOING INTO THE
DAY ON WEDNESDAY WITH TEMPERATURES FORECAST TO REACH THE SIXTIES AND
SURFACE DEWPOINTS NEAR SIXTY BY THE AFTERNOON AND EVENING HOURS.
THAT WILL COMBINE WITH A VERY DYNAMIC SYSTEM FEATURING A 500MB JET
OF OVER 100 KNOTS AND 850MB JET EXCEEDING 50 KNOTS. DESTABILIZATION
LATER IN THE DAY ON TOP OF THIS ALREADY VERY STRONG WIND FIELD
BRINGS CONCERNS FOR SEVERE THUNDERSTORMS. WHILE SEVERE POTENTIAL IS
DEPENDENT ON THE EXTENT OF DESTABILIZATION (WHICH DEPENDS ON
TIMING AND NORTHWARD WARM FRONTAL EXTENT), A SIGNIFICANT SEVERE
WEATHER EVENT IS POSSIBLE GIVEN THE BACKGROUND KINEMATIC PROFILE.
THE TIME OF INTEREST WOULD BE WEDNESDAY AFTERNOON INTO THE EARLY
OVERNIGHT HOURS AS A SURFACE FRONT/TROUGH CROSSES THROUGH THE
MIDWEST. ALL HAZARDS APPEAR ON THE TABLE AT THIS TIME GIVEN
FORECAST HODOGRAPHS AND THERMAL PROFILES AS WELL AS CONCERNS FOR
HEAVY RAINFALL. THE GREATEST CONCERN IS FOR AREAS NEAR AND SOUTH
OF I96 WHERE THE BEST SURFACE-BASED INSTABILITY IS EXPECTED, WHICH
ALIGNS WELL WITH THE CURRENT ENHANCED (LEVEL 3/5) RISK FROM THE
STORM PREDICTION CENTER.
- CHANCE OF RAIN SHOWERS THIS WEEKEND
THE WEATHER GETS NOTABLY QUIETER THURSDAY INTO THE WEEKEND AS THE
AFOREMENTIONED LOW DEPARTS. THE MAIN NOTABLE WEATHER AT THIS POINT
IS THE POTENTIAL FOR LIGHT RAIN SHOWERS FRIDAY AND THIS WEEKEND AS
AN UPPER-TROUGH SWINGS THROUGH THE REGION, AND A LOW CROSSES THE
OHIO VALLEY, MAINLY SOUTH OF I96. GIVEN DIVERGING SOLUTIONS IN THE
LARGE SCALE SYNOPTIC PATTERN PRECIPITATION CHANCES ARE 40 PERCENT OR
LESS. HIGHS WILL BE MILD IN THE 50S.
AVIATION /18Z TAFS THROUGH 18Z TUESDAY/
ISSUED AT 1258 PM EDT MON MAR 31 2025
MVFR IS EXPECTED TO LAST THROUGH LATE AFTERNOON OR EVENING BEFORE
CLOUDS EXIT THE REGION AND VFR BEGINS. BASES AROUND 1800-2000 FT
WILL SCATTER OUT AND LIFT SLIGHTLY AS WE APPROACH SUNSET. WINDS
DECREASE AFTER 00Z AND THEN VEER EASTERLY TUESDAY MORNING.
GRR WATCHES/WARNINGS/ADVISORIES
MI...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 2 AM EDT TUESDAY FOR LMZ844>849.
UPDATE...DUKE
DISCUSSION...THOMAS
AVIATION...HOVING
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