466
FXUS63 KGRR 271945
AFDGRR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND RAPIDS MI
345 PM EDT SUN APR 27 2025
KEY MESSAGES
- ELEVATED FIRE DANGER MONDAY
- STORMS POSSIBLE MONDAY NIGHT INTO TUESDAY
- SHOWERS AND STORMS POSSIBLE WEDNESDAY NIGHT INTO EARLY FRIDAY
DISCUSSION
ISSUED AT 345 PM EDT SUN APR 27 2025
- ELEVATED FIRE DANGER MONDAY
ANOTHER DRY DRY IS EXPECTED ON MONDAY ALTHOUGH WITH WARMER
TEMPERATURES AND STRONGER WINDS THE FIRE DANGER WILL BE ELEVATED.
THERE'S BEEN A FEW REPORTS OF GRASS/FIELD FIRES AROUND THE AREA
TODAY AND SIMILARLY LOW RH VALUES ARE EXPECTED AGAIN ON MONDAY.
PARTICULARLY VULNERABLE WILL BE THE MANISTEE NATIONAL FOREST
AREA.
- STORMS POSSIBLE MONDAY NIGHT INTO TUESDAY
THE LATER PERIODS OF THE 12Z CAMS ARE NOT VERY AMBITIOUS WITH
CONVECTION ON MONDAY AND MONDAY NIGHT, BOTH IN THE SPC MDT RISK AREA
TO THE WEST AS WELL AS IN WRN LWR MI. THIS COULD BE RELATED TO AN
UNFAVORABLE/DIVERGENT LOW LEVEL JET ORIENTATION AND/OR CONVECTIVE
INHIBITION ARRIVING WITHIN THE WARM SECTOR.
THAT SAID THE GENERAL SYNOPTIC SETUP FOR STRONG TO SEVERE STORMS IS
PRESENT OVER WRN LWR MI LATER MONDAY NIGHT WITH DEEP LAYER SHEAR
OF GREATER THAN 35 KTS, MUCAPES NEAR 1500 J/KG, AND A COLD FRONT
LEANING IN FROM THE NORTHWEST.
CAMS DO SEEM TO AGREE ON A LINE OF ORGANIZED CONVECTION IN NRN WI
MONDAY EVENING AND THAT MAY TURN/DIVE SOUTH-SOUTHEAST TOWARD WRN LWR
MI ALONG THE INSTABILITY GRADIENT OVERNIGHT. DEEP LAYER THICKNESS
PROGS WOULD ALSO SUPPORT SOUTHWARD PROPAGATING CONVECTION OVERNIGHT
SHOULD A DECENT COLD POOL/MATURE MCS DEVELOP UPSTREAM AND SURVIVE
DEEPER INTO THE NIGHT.
THERE IS STILL A LOW POTENTIAL FOR NEW/DIURNAL CONVECTION TO DEVELOP
TUESDAY ALONG THE COLD FRONT OR OLD CONVECTIVE OUTFLOW BOUNDARY
BEFORE IT EXITS, ESPECIALLY SOUTH AND EAST OF GRR, BUT THE MAIN
SEVERE WEATHER RISK IS SOUTH AND EAST OF MICHIGAN. ANOTHER
AREA/LINE OF SHOWERS AND STORMS COULD DEVELOP LATER IN THE DAY
TUESDAY WELL BEHIND/NORTH OF THE DEPARTING FRONT WITH AN H5
SHORTWAVE COMING IN FROM THE NORTHWEST.
- SHOWERS AND STORMS POSSIBLE WEDNESDAY NIGHT INTO EARLY FRIDAY
THE SYSTEM ON THURSDAY IS RAMPING UP IN TERMS OF POPS AND QPF AS A
SHORTWAVE AND ITS SFC REFLECTION TRACKS NORTHEAST ALONG THE
FRONTAL BOUNDARY SOUTH OF MI. THERE COULD BE A FEW STRONGER STORMS
LATER THURSDAY SHOULD THE SFC LOW TRACK FARTHER NORTH AND PULL
THE WARM FRONT INTO SRN LWR MI SO THAT WILL NEED WATCHED. THAT
SYSTEM IS FOLLOWED BY UPPER TROUGHING AND COOLER AIR ON FRIDAY
BEFORE HIGH PRESSURE MOVES IN FOR SATURDAY.
NEWER GUIDANCE IS PLACING MI MORE IN THE RIDGY PORTION OF THE
DEVELOPING OMEGA BLOCKING PATTERN FOR NEXT WEEKEND INDICATING DRY
AND PLEASANT WEATHER. HOWEVER A FEW MEMBERS/CLUSTERS STILL SUGGEST A
FARTHER WEST POSITION OF THE NEW ENGLAND TROUGH WHICH WOULD KEEP US
THE COOLER SIDE.
AVIATION /18Z TAFS THROUGH 18Z MONDAY/
ISSUED AT 153 PM EDT SUN APR 27 2025
LIGHT AND VARIABLE WINDS ARE TRENDING MORE FROM THE SOUTH THIS
AFTERNOON. VFR CONDITIONS ARE LIKELY OVER THE NEXT 24 HOURS, WITH
JUST A SLIGHT CHANCE OF SHOWERS DURING THE DAY MONDAY NEAR AND
NORTH OF LUDINGTON (LDM). THERE MAY BE A BIT MORE VARIABILITY IN
THE WIND DIRECTION THIS AFTERNOON VS TONIGHT NEAR LAKE MICHIGAN,
INCLUDING MKG, DUE TO THE INFLUENCE OF THE LAKE MICHIGAN LAKE
BREEZE. SOUTH WINDS GUSTING OVER 20 KNOTS ARE EXPECTED AFTER 14Z
MONDAY.
MARINE
ISSUED AT 345 PM EDT SUN APR 27 2025
INCREASING SOUTHERLY FLOW MONDAY ON THE BACK SIDE OF A DEPARTING
SFC HIGH LEADS TO HAZARDOUS WINDS AND WAVES DEVELOPING; INITIALLY
NORTH OF GRAND HAVEN MONDAY MORNING THEN OVER THE REST OF THE
NEARSHORE BY MONDAY EVENING. HAZARDOUS WINDS AND WAVES CONTINUING
INTO MONDAY NIGHT AND TUESDAY WITH A COLD FRONTAL PASSAGE BRINGING
THE THREAT FOR A FEW STRONG TO SEVERE STORMS AND A WIND SHIFT.
GRR WATCHES/WARNINGS/ADVISORIES
MI...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 4 PM MONDAY TO 8 PM EDT TUESDAY FOR
LMZ844>846.
SMALL CRAFT ADVISORY FROM 8 AM MONDAY TO 8 PM EDT TUESDAY FOR
LMZ847>849.
DISCUSSION...MEADE
AVIATION...CAS
MARINE...MEADE
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