786
FXUS63 KGRR 090539
AFDGRR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND RAPIDS MI
139 AM EDT MON JUN 9 2025
KEY MESSAGES
- SHOWERS AND EMBEDDED STORMS THIS EVENING AND MONDAY AFTERNOON
- BRIEF DRY PERIOD MID-WEEK
- SEASONABLE TEMPERATURES AND UNSETTLED END OF WEEK AND WEEKEND
DISCUSSION
ISSUED AT 311 PM EDT SUN JUN 8 2025
- SHOWERS AND EMBEDDED STORMS THIS EVENING AND MONDAY AFTERNOON
WHAT WAS ONCE A FORMIDABLE LINE OF SHOWERS WITH EMBEDDED STORMS
OVER WISCONSIN EARLIER, HAS DIMINISHED A BIT OVER THE LAST FEW
HOURS AS IT APPROACHES LAKE MICHIGAN. THIS HAS BEEN EXPECTED TO
OCCUR AND IT IS NOW COMING TO FRUITION. THE ATMOSPHERE IS JUST NOT
LINING UP WELL FOR GOOD ORGANIZATION TO OCCUR. DEEP LAYER SHEAR IS
MORE THAN SUFFICIENT TO HELP THE CAUSE WITH VALUES 35-40 KNOTS.
INSTABILITY IS THE PROBLEM WITH NO INSTABILITY OVER THE FORECAST
AREA AS OF 18Z, AND INSUFFICIENT LOW LEVEL FLOW TO ADVECT
SIGNIFICANT MOISTURE OVER THE AREA BEFORE THE FRONT ARRIVES HERE.
THERE WILL BE JUST ENOUGH TO KEEP THE SHOWERS GOING, AND MAYBE AN
EMBEDDED STORM THIS EVENING. THERE MAY BE A BRIEF UPTICK IN THE
COVERAGE OVER THE EASTERN PORTION OF THE FORECAST AREA AS BETTER
MOISTURE IS PRESENT THERE, LINGERING FROM THE LIGHT RAIN LAST
NIGHT. ALL SHOWERS AND STORMS WILL WEAKEN TO LINGERING SHOWERS
OVERNIGHT.
WE WILL SEE CLEARING TAKE PLACE THEN OVERNIGHT AND ON MONDAY
MORNING AS WE WILL BECOME UNDER THE INFLUENCE OF THE DRY SLOT
BETWEEN THE FRONT AND THE UPPER LOW DURING THIS PERIOD. THEN, THE
UPPER LOW WILL ARRIVE MONDAY AFTERNOON DURING PEAK HEATING.
INSTABILITY WILL BE WEAK AGAIN WITH A FEW HUNDRED J/KG OF CAPE.
THE STRONGER WAVE WILL HELP TO COMPENSATE FOR THIS A BIT, AND
PRODUCE SCATTERED TO NUMEROUS SHOWERS AND A FEW STORMS MONDAY
AFTERNOON AND EARLY EVENING BEFORE DISSIPATING.
- BRIEF DRY PERIOD MID-WEEK
TUESDAY WILL SEE LESS OF A CHANCE FOR RAIN SHOWERS AS THE UPPER
LOW SETTLING IN ON MONDAY WILL BE LIFTING OUT ON TUESDAY. WE WILL
BE CLOSE ENOUGH TO THE WEAKENING LOW THAT WE COULD SEE ONE MORE
WEAK SHORT WAVE PUSH THROUGH. FOR THIS REASON, WE ARE KEEPING A
SLIGHT CHANCE OF RAIN SHOWERS FOR TUESDAY AFTERNOON.
MODEL ENSEMBLE MEANS ARE KEEPING WEDNESDAY GENERALLY DRY ACROSS
THE AREA WITH SEASONABLE TEMPERATURES. THE UPPER JET WILL BE
POSITIONED FAR ENOUGH NORTH OVER CANADA THAT WE WILL NOT SEE THE
DIRECT IMPACTS FROM IT. HOWEVER, A WEAK COLD FRONT TRAILING SW OF
IT WILL PASS THROUGH THE STATE WEDNESDAY AFTERNOON. THIS FRONT IS
SHOWN TO BE MAINLY DRY WITH JUST A VERY SMALL CHANCE OF A SHOWER
WITH IT. THERE IS NO MOISTURE FOR IT TO WORK WITH.
- SEASONABLE TEMPERATURES AND UNSETTLED END OF WEEK AND WEEKEND
EVEN THOUGH THE FRONT IS EXPECTED TO MOVE THROUGH DRY ON
WEDNESDAY, IT WILL BECOME THE FOCUS FOR SMALL, BUT OCCASIONAL CHANCES
OF SHOWERS AND A FEW STORMS FROM THURSDAY THROUGH SATURDAY.
THE FRONT WILL WILL SLOWLY SINK TO ABOUT THE MICHIGAN/INDIANA
BORDER BY THURSDAY AFTERNOON BEFORE STALLING OUT AS IT ALIGNS WITH
THE UPPER FLOW. WE WILL THEN SEE SHORT WAVES EMBEDDED IN THE UPPER
FLOW HELP SUPPORT WAVES OF SHOWERS AND STORMS ALONG THE STALLED
OUT FRONT. THE HIGHEST PROBABILITY OF SHOWERS AND STORMS WILL BE
ACROSS THE SOUTH, CLOSER TO THE FRONT. ALL OF THE AREA WILL SEE
RAIN CHANCES THOUGH DURING THIS TIME FRAME. SEVERE WEATHER CHANCES
WILL LIKELY BE FOCUSED JUST SOUTH OF THE AREA WHERE THE MUCH
BETTER INSTABILITY IN THE WARM SECTOR WILL BE FOUND.
THE MODEL ENSEMBLES ARE IN FAIRLY GOOD AGREEMENT IN SHOWING HIGH
PRESSURE ACROSS ONTARIO HELPING TO PUSH THE STALLED FRONT A BIT
FURTHER SOUTH BY SUNDAY. THIS WOULD RESULT IN THE WAVES ALONG THE
FRONT STAYING FAR ENOUGH SOUTH THAT WE WOULD END UP LOSING OUR
RAIN CHANCES. THIS WOULD ALSO RESULT IN TEMPERATURES COOLING OFF A
LITTLE BIT.
AVIATION /06Z TAFS THROUGH 06Z TUESDAY/
ISSUED AT 138 AM EDT MON JUN 9 2025
PATCHY IFR OVERNIGHT WITH LOW STRATUS AND SHALLOW GROUND FOG, BUT
THESE CONDITIONS WILL BE TRANSIENT AS WINDS PICK UP BEHIND A COLD
FRONT. SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS WILL FIRE UP
DURING THE AFTERNOON THEN DECREASE AT SUNSET. WEST WINDS WILL GUST
OVER 20 KNOTS AT TIMES TODAY.
MARINE
ISSUED AT 138 AM EDT MON JUN 9 2025
WINDS AND WAVES ARE EXPECTED TO BE RELATIVELY CALM THIS WEEK WITH
WINDS MOSTLY BELOW 20 KNOTS AND WAVES MOSTLY 3 FEET OR LESS.
GRR WATCHES/WARNINGS/ADVISORIES
MI...NONE.
MARINE...NONE.
DISCUSSION...NJJ
AVIATION...OSTUNO
MARINE...OSTUNO
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