Special Weather Statement, NWS Grand Rapids, MI

Area Forecast Discussion
National Weather Service Grand Rapids MI
742 PM EDT Mon Jul 5 2021

LATEST UPDATE...
Aviation

.SYNOPSIS...
Issued at 317 PM EDT Mon Jul 5 2021

- Slow moving front brings chance for rain, severe weather
  through Tuesday

&&

.DISCUSSION...(This evening through next Monday)
Issued at 317 PM EDT Mon Jul 5 2021

Large scale pattern transitioning into zonal flow across the
northern CONUS this week. A slow-moving cold front will focus
some convection this evening across central Lower Michigan and
again on Tuesday.

Some mid-level capping this afternoon is eroding as heights fall
and the first updrafts are appearing now across our northern
forecast area as forecast by the Convective Allowing Models. We
expect the line of cu currently seen across this area to continue
to fill and CAPE values approach 3000 J/kg in this area through
the afternoon into early evening. Shear values are only around 20
knots so pulse type storms and multicell clusters are expected to
be the dominant form. Activity weakens after sunset as instability
decreases.

The focus for storms moves a bit south on Tuesday as the front
sags through central Lower Michigan. Again, storm mode should be
pulsing multicells as shear remains weak. Hail and isolated wind
damage are the primary threats.

The front moves south on Wednesday and a surface wave of low
pressure moves along it with some embedded storms, but severe
weather is not expected. After that Canadian surface high builds
in and the model trends have been to keep the bulk of rain with
the passage of the next shortwave trough this weekend to the
south of Lower Michigan.

&&

.AVIATION...(For the 00Z TAFS through 00Z Tuesday evening)
Issued at 732 PM EDT Mon Jul 5 2021

The stronger wind gusts...over 25 knots will diminish steadily
this evening.

The atmosphere is rather unstable and a few showers have developed
around the TAF sites in Southwest Lower MI. With the approach of a
front from the northwest....a risk for thunderstorms exists this
evening. We will feature VCTS around the main windows for
potential storms. Gusty winds may accompany any storm. Then the
atmosphere gradually stabilizes especially after midnight. Outside
of any storm...VFR weather is expected. Then for Tuesday...we warm
up again...and a few storms could get going mid to late
afternoon. The main focus for these storms is predicted to be
north of KGRR and KMKG through 00z Wed. Much less wind is
predicted for Tuesday as compared to Monday...mostly under 20
knots.

&&

.MARINE...
Issued at 317 PM EDT Mon Jul 5 2021

The Small Craft Advisory continues into this evening. Beach report
from Ludington had 4 foot waves this morning and winds are
continuing to gust over 22 knots this afternoon. Winds will be a
bit lower on Tuesday as the sfc pressure trough sags south and
waves should remain in the 2 to 4 foot range.

&&

.GRR WATCHES/WARNINGS/ADVISORIES...
MI...Beach Hazards Statement until 11 PM EDT this evening for MIZ037-
     043-050-056.

LM...Small Craft Advisory until 11 PM EDT this evening for LMZ846>849.

&&

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

Hazardous Weather Outlook
National Weather Service Grand Rapids MI
513 pM EDT Mon Jul 5 2021

MIZ037>040-043>046-050>052-056>059-064>067-071>074-060815-
Mason-Lake-Osceola-Clare-Oceana-Newaygo-Mecosta-Isabella-Muskegon-
Montcalm-Gratiot-Ottawa-Kent-Ionia-Clinton-Allegan-Barry-Eaton-
Ingham-Van Buren-Kalamazoo-Calhoun-Jackson-
513 pM EDT Mon Jul 5 2021

This hazardous weather outlook is for portions of southwest Lower
Michigan.

.DAY ONE...This Evening and Tonight

Scattered thunderstorms may develop in Central and Western Michigan
this evening and linger into tonight. An isolated severe
thunderstorm with large hail or damaging wind gusts cannot be ruled
out.

Waves and currents on Lake Michigan will pose a moderate to high
risk to swimmers into this evening, mainly north of Grand Haven
toward Ludington. Strong currents can pull swimmers into deeper
water. These currents can occur along any beach but will most
frequently occur near south piers today.

.DAYS TWO THROUGH SEVEN...Tuesday through Sunday

Occasional thunderstorms are possible Tuesday night into Wednesday
and again Friday or Saturday.

.SPOTTER INFORMATION STATEMENT...

Spotters are encouraged to report local severe weather to the
National Weather Service via phone, amateur radio networks, or
social media.

LMZ844>849-060815-
St Joseph to South Haven MI-South Haven to Holland MI-
Holland to Grand Haven MI-Grand Haven to Whitehall MI-
Whitehall to Pentwater MI-Pentwater to Manistee MI-
412 AM EDT Mon Jul 5 2021

This hazardous weather outlook is for portions of southwest Lower
Michigan.

.DAY ONE...This Evening and Tonight

Scattered thunderstorms may develop in Central and Western Michigan
and over Lake Michigan this evening and linger into tonight. An
isolated severe thunderstorm with large hail or damaging wind gusts
cannot be ruled out.

Winds and waves on Lake Michigan will be a hazard to small craft
mainly near and north of Grand Haven. Waves and currents will pose a
moderate to high risk to swimmers into this evening, mainly north of
Grand Haven toward Ludington. Strong currents can pull swimmers into
deeper water. These currents can occur along any beach but will most
frequently occur near south piers today.

.DAYS TWO THROUGH SEVEN...Tuesday through Sunday

Occasional thunderstorms are possible Tuesday night into Wednesday
and again Friday or Saturday.

.SPOTTER INFORMATION STATEMENT...

Spotters are encouraged to report local severe weather to the
National Weather Service via phone, amateur radio networks, or
social media.