000
FXUS63 KGRR 181859
AFDGRR

Area Forecast Discussion
National Weather Service Grand Rapids MI
259 PM EDT Fri Jun 18 2021

LATEST UPDATE...
Synopsis/Discussion/Marine

.SYNOPSIS...
Issued at 258 PM EDT Fri Jun 18 2021

- Marginal Risk for Severe on Saturday and Sunday

- Upper Troughing and cool weather next week

&&

.DISCUSSION...(This evening through next Friday)
Issued at 258 PM EDT Fri Jun 18 2021

- Marginal Risk for Severe on Saturday and Sunday

Strong shear profiles are forecast for Saturday morning as area of
showers and storms moves in from the west northwest. Instability
is marginal and appears to remain mostly elevated which will
reduce the severe wind threat. The storms should be moving east of
the forecast area by afternoon.

The next organized severe threat comes Sunday evening and again
the shear profiles are impressive with over 40 knots and this time
some sfc based instability. So this event could produce areas of
wind damage and perhaps some large hail. The storms are progged to
get going during late afternoon in an area of strong warm
advection across our central forecast area followed by additional
convection later in the evening as the sfc trough/cold front
approaches.

- Upper Troughing and cool weather next week

Strong height falls Sunday night will usher in another spell of
cool weather with temperatures running about 10 to 15 degrees
below normal for early in the week with moderating temps by late
week.

&&

.AVIATION...(For the 18Z TAFS through 18Z Saturday afternoon)
Issued at 133 PM EDT Fri Jun 18 2021

VFR conditions expected into Saturday morning. There could be
some scattered showers and thunderstorms near JXN this afternoon.
Otherwise, VFR conditions until the chance of some MVFR and
isolated IFR in showers and thunderstorms beginning around 12
Sunday. Winds will be going west this afternoon around 10 knots
and diminishing to less than 10 knots tonight.


&&

.MARINE...
Issued at 258 PM EDT Fri Jun 18 2021

Winds and waves should remain relatively light over the weekend
but some thunderstorms could bring gusty winds Saturday morning and
again Sunday evening. Stronger north winds are possible early next
week and a Small Craft Advisory may be needed for Monday.

&&

.GRR WATCHES/WARNINGS/ADVISORIES...
MI...None.
LM...None.
&&

$$

SYNOPSIS...Ostuno
DISCUSSION...Ostuno
AVIATION...Ostuno
MARINE...Ostuno

NWS GRR Office Area Forecast Discussion