287
FXUS63 KGRR 200739
AFDGRR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND RAPIDS MI
339 AM EDT TUE MAY 20 2025
KEY MESSAGES
- COOL, WET AND WINDY TODAY
- RAIN LINGERS THROUGH TOMORROW
- COLDER TEMPS LINGER WITH WARMTH AHEAD
DISCUSSION
ISSUED AT 330 AM EDT TUE MAY 20 2025
- COOL, WET AND WINDY TODAY
THE MAIN FORECAST QUESTION TODAY REMAINS THE TIMING AND TRACK OF
THE INCOMING PRECIPITATION. MODELS REMAIN CONSISTENT WITH THE
NEGATIVELY TILTED UPPER LEVEL LOW AND CORRESPONDING SFC LOW MOVING
FROM THE SOUTHWEST TO THE NORTH EAST THIS AFTERNOON. A STRONG
MOISTURE FIELD REMAINS ON THE LEADING EDGE OF THAT LOW WHICH WILL
ADVECT THROUGH SOUTHERN LOWER THIS AFTERNOON. EXPECT RAIN TO BEGIN
FROM THE SOUTHWEST AND OVERSPREAD THE AREA THROUGH THE DAY AND
INTO THIS EVENING.
THE PRECIPITATION AMOUNTS REMAIN FAIRLY CONSISTENT WITH THE
HEAVIEST RAINFALL OCCURING THIS AFTERNOON, THOUGH IN THAT 6 HOUR
TIMEFRAME IT SHOULD BE TWO TO THREE TENTHS. OVERALL THIS SHOULD
BE A SOAKING RAIN WITH AMOUNTS RANGING BETWEEN A HALF AN INCH TO
THREE QUARTERS OF AN INCH. SOME ENSEMBLES DO SHOW SLIGHTLY HIGHER
AMOUNTS WITH AT MOST AN INCH AN A HALF, HOWEVER THOSE ARE OUTLIERS
AND NO FLOODING IS EXPECTED. THE OTHER FORECAST CONCERN IS GUSTY
WINDS THIS MORNING AND THROUGH THE AFTERNOON. AS THE LOW MOVES
INTO THE REGION THIS MORNING THERE REMAINS A STRONG PRESSURE
GRADIENT AS THE HIGH IS PUSHED EASTWARD. A LOW LEVEL JET OF 45 TO
50 KTS WILL BE SITTING AROUND 2 TO 3KFT. COUPLE WITH THE MOISTURE
BOUNDARY AND THE MIXING ALOFT AND GUSTS OF 30 TO 40 MPH WINDS WILL
BE POSSIBLE. THERE IS SOME LIMITING FACTORS BUT GIVEN PRECIP
LOADING WE MAY NEED A WIND ADVISORY. HAVE HELD OFF FOR NOW GIVE
THE EASTERN FLOW THOUGH SOME OF THE ENSEMBLE MEMBERS BRIEFLY REACH
INTO THE 40S. THE GUSTIEST WINDS WILL BE WEST OF US 131,
ESPECIALLY ALONG THE LAKESHORE.
- RAIN LINGERS THROUGH TOMORROW
WINDS WILL SLIGHT WITH THE HEAVIEST RAIN SHOWERS AND THE AREA
BECOMES MORE STABLE AND LIGHT RAIN WILL PERSIST THROUGH TOMORROW
AS THE LOW CYCLES THROUGH THE MID ATLANTIC. COLD, WET WEATHER
WILL CONTINUE ON THE BACKSIDE OF THE LOW WITH RAIN FINALLY
TAPERING OFF LATE WEDNESDAY, EARLY THURSDAY.
- COLDER TEMPS LINGER WITH WARMTH AHEAD
COOLER THAN NORMAL TEMPERATURES WILL PERSIST THROUGH THE WEEK WITH
TEMPERATURES 10 TO 20 DEGREES BELOW NORMAL. HIGHS SHOULD REMAIN IN
THE 50S THROUGH THE WORK WEEK, FINALLY REBOUNDING INTO THE LOW TO
MID 60S HEADING INTO THE HOLIDAY WEEKEND.
AVIATION /06Z TAFS THROUGH 06Z WEDNESDAY/
ISSUED AT 210 AM EDT TUE MAY 20 2025
THERE REMAINS SEVERAL ISSUES OVER THIS TAF PERIOD. THE FIRST IS
THE LLWS WITH STRONG WINDS OF 40 TO 45 KTS BETWEEN 1KFT TO 2KFT.
WHILE THOSE WINDS WILL REMAIN THROUGH MOST OF THE TAF PERIOD IT
WILL BE LESS OF AN ISSUE DUE TO THE MIXING THAT WILL OCCUR
BRINGING THE GUSTY WINDS TO THE SFC. EXPECT WINDS TO MIX DOWN
AROUND 11Z AND THEN CONTINUING THROUGH THE DAY. SHOWERS WILL BE
MOVING IN FROM THE SOUTH. HEAVIEST SHOWERS WILL OCCUR AFTER 21Z
WITH MVFR CIGS AND VSBYS POSSIBLE BETWEEN 21Z UNTIL 03Z. AFTER 03Z
VSBYS SHOULD IMPROVE AS SHOWERS LIGHTEN. HOWEVER, MVFR CIGS WILL
PERSIST INTO WEDNESDAY MORNING.
MARINE
ISSUED AT 330 AM EDT TUE MAY 20 2025
LOOKING AT THE LAKE TODAY, WINDS WILL CONTINUE INCREASE AS WINDS
MIX TO THE SURFACE. MODELS ARE IN GOOD AGREEMENT WITH RAMPING UP
THE WINDS TODAY. WHILE THE FLOW WILL BE OFF SHORE FLOW THERE IS
ENOUGH SIGNAL THAT SOUTH OF THE POINTS THERE WILL BE GALES
BETWEEN 13Z TO 21Z. WINDS HAZARDOUS TO SMALL CRAFT WILL LINGER
INTO TUESDAY NIGHT.
GRR WATCHES/WARNINGS/ADVISORIES
MI...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 9 AM EDT THIS MORNING FOR LMZ844>847.
SMALL CRAFT ADVISORY FROM 5 PM THIS AFTERNOON TO 2 AM EDT
WEDNESDAY FOR LMZ844>847.
GALE WARNING FROM 9 AM THIS MORNING TO 5 PM EDT THIS AFTERNOON
FOR LMZ844>847.
SMALL CRAFT ADVISORY UNTIL 2 AM EDT WEDNESDAY FOR LMZ848-849.
DISCUSSION...CERU
AVIATION...CERU
MARINE...CERU
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