Special Weather Statement, NWS Grand Rapids, MI

Area Forecast Discussion
National Weather Service Grand Rapids MI
138 PM EDT Thu Aug 2 2018

LATEST UPDATE...
Aviation

.SYNOPSIS...
Issued at 330 AM EDT Thu Aug 2 2018

A frontal boundary approaching from Wisconsin early this morning
will stall over Lower Michigan today, leading to scattered to
numerous showers and thunderstorms. The front will dissipate later
tonight and Friday, and dry and warm weather will prevail for the
weekend.

&&

.SHORT TERM...(Today through Saturday)
Issued at 330 AM EDT Thu Aug 2 2018

Short range guidance/CAMs have not been handling the current
convection too well and have made some fairly significant
adjustments to pops through daybreak to reflect current radar
trends. Convection is the result of theta-e advection on nose of
a 25 kt low level jet ahead of the approaching front.

Our rain chances today are some of the best we've seen in some
time in terms of areal coverage. The ongoing activity is expected
to wane by mid morning, with new diurnal convection developing
along the sfc front in the afternoon. This will be aided by a
decent mid level shortwave, and possible mesoscale contributions
from various MCVs currently noted along the front in regional
radar mosaic loop.

Amount of sunshine/heating will dictate degree of instability
today, but HREF ensemble mean sfc capes of 1000-2000 J/KG are
progged. Deep layer shear will be less than 20kts this afternoon,
so threat of organized strong/svr convection is low but can't rule
out some isolated gusty winds/small hail in some of the stronger
cells along the front later today.

General consensus among the CAMs/HREF is that scattered
convection today will eventually transition that a broken line of
pulse storms along the sfc front by late in the day in a band
from roughly Saginaw southwest to Ionia to Paw Paw/AZO. This
activity continues through the evening hours and does not really
move much since the front stalls out. The storms weaken after
sunset, but some isolated showers may linger well into the night
with the front still in the area.

Fog/stratus looks to be an issue later tonight into Friday
morning, but arrival of drier/more stable air mass from the west
should preclude afternoon convection on Friday. Exception may be
near LAN/JXN where weak sfc convergence and 500-1000 J/KG of cape
could pop a storm or two. High confidence for dry and warmer
weather on Saturday as sfc and shortwave ridging, along with H8
temps near 20C, impact the area.

.LONG TERM...(Saturday night through Wednesday)
Issued at 330 AM EDT Thu Aug 2 2018

We are looking at a more unsettled, and potentially active weather
pattern at times in the long term. Lots of details to be worked out
yet however.

The long term will start out dry as the upper ridge axis approaching
the area at the end of the short term on Sat, will still be close
enough to keep the rain at bay. This will shift east of the area on
Sunday, and allow a short wave and associated sfc front approach
later in the day and Sunday night. It appears that the front and
associated rain should sink just south of the CWFA by Monday.

There is an interesting feature that we are, and will continue to
monitor for the Tue time frame. The front will initially be south of
the area. The models agree that there should be a fairly healthy
short wave coming in to interact with it, along with some potential
coupling of upper jets. The Euro has been fairly consistent in
indicating some heavy swaths of rain with a strengthening sfc low as
it comes overhead. The GFS is a bit further south, and not quite as
organized. A lot of things have to come together just right, but
there could be a severe/heavy rain event on Tue.

Additional short wave energy will be in the vicinity of the region
still on Wed behind the potentially bigger event on Tue. This will
keep a chance of showers/storms for the area on Wed. Cooler air will
be settling in for the area with the upper troughing over the
region.

&&

.AVIATION...(For the 18Z TAFS through 18Z Friday afternoon)
Issued at 133 PM EDT Thu Aug 2 2018

The atmosphere continues to destabilize and showers and
thunderstorms are expected to expand around the region in the next
by 19z. It appears they will form into a broken line from roughly
KGRR to just west of KAZO and then head east. Thus nearly all TAF
sites feature a period of showers and thunderstorms prior to
sunset.

Low clouds and fog look likely to move in tonight. IFR and lower
impacts are possible. Looking upstream at this time...lots of low
clouds exist in Wisconsin, so as this system builds east, tomorrow
may be fairly cloudy with mainly MVFR impacts during the day.

&&

.MARINE...
Issued at 330 AM EDT Thu Aug 2 2018

Southwest flow is staying in check for now but will continue to
monitor for potential brief period of higher waves of 3-4 ft
today, mainly between Holland and Whitehall. Will advertise a
moderate risk of rip currents in this area today.

&&

.HYDROLOGY...
Issued at 1233 PM EDT Thu Aug 2 2018

River levels are running around to a little below normal for the
time of year. Abnormally dry conditions continue over much of the
area, especially in the greater Lansing region. The U.S. Drought
Monitor shows a moderate drought has developed over that area.

Localized heavy rain will be possible today. It will then be dry
through most of the weekend. A front will stall out over the area
early next week and a slow moving shortwave will track in from the
west. The flood potential is low, but beneficial rain is possible
today and early next week.

&&

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

SYNOPSIS...Meade
SHORT TERM...Meade
LONG TERM...NJJ
AVIATION...MJS
HYDROLOGY...63
MARINE...Meade

Hazardous Weather Outlook
National Weather Service Grand Rapids MI
118 PM EDT Thu Aug 2 2018

MIZ037>040-043>046-050>052-056>059-064>067-071>074-030845-
Mason-Lake-Osceola-Clare-Oceana-Newaygo-Mecosta-Isabella-Muskegon-
Montcalm-Gratiot-Ottawa-Kent-Ionia-Clinton-Allegan-Barry-Eaton-
Ingham-Van Buren-Kalamazoo-Calhoun-Jackson-
118 PM EDT Thu Aug 2 2018

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

.DAY ONE...This Afternoon and Tonight

Scattered to numerous thunderstorms are expected this afternoon into
this evening. An isolated severe thunderstorm is possible with a
local damaging wind and large hail risk being the main hazard. Any
stronger storms could contain gusty winds, small hail, frequent
lightning and heavy downpours.

Locally dense fog may form late tonight.

.DAYS TWO THROUGH SEVEN...Friday through Wednesday

A few non severe storms are possible Friday around Lansing and
Jackson. After a hot, humid and mostly dry weekend, periodic
thunderstorm chances will exist next week.

.SPOTTER INFORMATION STATEMENT...

Spotter activation will not be needed.

LMZ844>849-030845-
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-
118 PM EDT Thu Aug 2 2018

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

.DAY ONE...This Afternoon and Tonight

Scattered thunderstorms this afternoon are not expected to be severe
but may produce cloud to water lightning strikes, small hail, and
gusty winds. A moderate risk of rip currents will exist today for
Muskegon, Grand Haven, and Holland area beaches.

.DAYS TWO THROUGH SEVEN...Friday through Wednesday

After a mostly dry weekend, periodic thunderstorm chances will
exist next week.

.SPOTTER INFORMATION STATEMENT...

Spotter activation will not be needed.

Meade  MJS

Special Weather Statement
National Weather Service Grand Rapids MI
921 AM EDT THU AUG 2 2018

MIZ039-040-046-021400-
Isabella MI-Osceola MI-Clare MI-
921 AM EDT THU AUG 2 2018

...SIGNIFICANT WEATHER ADVISORY...

At 921 AM EDT, Doppler radar was tracking a strong thunderstorm near
Lake, or 12 miles northwest of Clare, moving northeast at 45 mph.

Winds in excess of 40 mph with downed tree limbs will be possible
with this storm.

Locations impacted include...
Clare...               Marion...              Farwell...
Lake...                Brinton...             Temple...
Lake George...         Leota...

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Torrential rainfall and frequent cloud to ground lightning are also
occurring with this storm. Localized flooding is possible. Lightning
can strike 10 miles away from a thunderstorm.

Seek a safe shelter inside a building or vehicle. Do not drive your
vehicle through flooded roadways.

&&

LAT...LON 4416 8461 4381 8461 4376 8503 4408 8524
      4417 8505
TIME...MOT...LOC 1321Z 246DEG 41KT 4391 8499

MJS

Special Weather Statement
National Weather Service Grand Rapids MI
1000 AM EDT THU AUG 2 2018

MIZ040-046-021430-
Isabella MI-Clare MI-
1000 AM EDT THU AUG 2 2018

...SIGNIFICANT WEATHER ADVISORY...

At 959 AM EDT, Doppler radar was tracking strong thunderstorms along
a line extending from 5 miles southwest of Roscommon Township to near
Loomis. Movement was northeast at 45 mph.

Winds in excess of 40 mph with downed tree limbs will be possible
with these storms.

Locations impacted include...
Loomis...

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Torrential rainfall and frequent cloud to ground lightning are also
occurring with these storms. Localized flooding is possible.
Lightning can strike 10 miles away from a thunderstorm.

Seek a safe shelter inside a building or vehicle. Do not drive your
vehicle through flooded roadways.

&&

LAT...LON 4371 8461 4370 8465 4416 8488 4416 8461
TIME...MOT...LOC 1359Z 241DEG 39KT 4416 8477 4382 8460

MJS

Special Weather Statement
National Weather Service Grand Rapids MI
142 PM EDT THU AUG 2 2018

MIZ039-040-045-046-021845-
Isabella MI-Osceola MI-Mecosta MI-Clare MI-
142 PM EDT THU AUG 2 2018

...SIGNIFICANT WEATHER ADVISORY...

At 141 PM EDT, Doppler radar was tracking a strong thunderstorm over
Lake Isabella, or 10 miles west of Mount Pleasant, moving northeast
at 40 mph.

Winds in excess of 40 mph with downed tree limbs will be possible
with this storm, in addition to half inch size hail.

Locations impacted include...
Mount Pleasant...      Big Rapids...          Clare...
Evart...               Farwell...             Mecosta...
Rosebush...            Barryton...            Canadian Lakes...
Lake Isabella...       Lake...                Paris...
Hersey...              Stanwood...            Brinton...
Sylvester...           Lake George...         Chippewa Lake...
Delwin...              Gibos Corners...

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Torrential rainfall and frequent cloud to ground lightning are also
occurring with this storm. Localized flooding is possible. Lightning
can strike 10 miles away from a thunderstorm.

Seek a safe shelter inside a building or vehicle. Do not drive your
vehicle through flooded roadways.

&&

LAT...LON 4368 8461 4347 8513 4347 8532 4369 8556
      4379 8556 4416 8489 4416 8461
TIME...MOT...LOC 1741Z 234DEG 36KT 4364 8497

HOVING