Isolated severe thunderstorm wind gusts brought down several trees and power lines across portions of Calhoun and Jackson counties.
Every event with a place to put it. Tap one for its entry below.
Deaths and injuries are direct and indirect together, as the offices filed them. Damage is property and crops in the dollars of the year, not adjusted for inflation, and only where an office estimated it.
The episode as NWS GRR wrote it up.
Isolated severe thunderstorm wind gusts brought down several trees and power lines across portions of Calhoun and Jackson counties.
The local office's own words before the first event, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.
NWS Grand Rapids, MI wrote its last area forecast discussion before the first event at Aug 6, 10:23 AM EST, 2 hours 12 minutes earlier.
Area Forecast Discussion National Weather Service Grand Rapids MI 1123 AM EDT Mon Aug 6 2018 LATEST UPDATE... Update .SYNOPSIS... Issued at 210 AM EDT Mon Aug 6 2018 A slow moving frontal boundary will track southeastward through the Western Great Lakes Region today through Tuesday. Showers and thunderstorms will accompany the passage of this system. Locally heavy rains, gusty winds and possibly hail could occur with any stronger storms. A weak area of high pressure will move in for Wednesday pushing any remaining showers and thunderstorms into Ohio and Indiana by evening. && .UPDATE... Issued at 1124 AM EDT Mon Aug 6 2018 It would seem the severe storm threat has shifted south (I talked to SPC's day one forecaster 1045 am) due to the multiple areas of showers and thunderstorms. The outflow from these storms is already south of I-80, west of Fort Wayne Indiana. There is one more area of showers and thunderstorms coming on shore now, that should be the last area of convection before we see a dry period early to mid afternoon. There is an upper wave (as seen on the water vapor loops) that is assoicated with jet streak on the southern branch of the polar jet that comes through the area this evening. The moisture transport vectors in the 1000/850 layer and the low level jet assoicated with that wave have adjusted southward to between I-94 and I-80 this evening. So we are thinking the significant risk for severe storms is for the most part south of the GRR CWA. There may be enough drying behind this current convection area to allow some warming this afternoon over our CWA so we do expect more storms this evening but the severe threat is expected to be south of the area. UPDATE Issued at 729 AM EDT Mon Aug 6 2018 The dissipating complex of storms continues to track further south than forecasted by the models. This update issued earlier reflected higher potential for rain this morning especially South Haven to Battle Creek. UPDATE Issued at 534 AM EDT Mon Aug 6 2018 Based on recent model and radar trends it looks like this MCS will impact locations further south in the CWA. I have therefore updated POPs to reflect this system, mainly for this morning. && .SHORT TERM...(Today through Wednesday) Issued at 210 AM EDT Mon Aug 6 2018 The main challenges in the short term deal with the timing and strength of the thunderstorms today into Tuesday. To start, the area of thunderstorms upstream in Southern Wisconsin into Northern Iowa were forming along a nearly stationary boundary in that region. To the north of the developing convection a widespread area of stratiform rain existed through Central Wisconsin. Elevated instability was noted with the storms generally anchored to the 850 mb axis of instability. This is where a low level jet was aimed, providing the necessary lift to generate the storms. The 850 mb instability axis stretched eastward ahead of these storms into Southern Lower Michigan. Instability values are forecasted to drop off ahead of these storms towards daybreak. Thus as these storms build east through the remainder of the early morning hours, they should feature a general weakening trend. That said, a few storms could still be strong given elevated deep layer shear values. The primary impacted region that will see the storms and rain this morning will be generally along and north of a Holland to Alma line. This area of morning showers and storms will act to push the surface frontal zone further south which will influence the afternoon setup. With a further south position of the front today, this will have an impact on the high temperatures, which have been lowered accordingly. Looking at the afternoon, with the frontal zone forecasted to be south of the morning convection, this will favor the region roughly south of a Muskegon to Lansing line for the strongest convection. If this frontal zone ends up being driven further south than forecasted, the axis of strongest convection may end up being closer to I94. The combination of afternoon CAPE values topping 1500 j/kg and 0 to 6km bulk shear values around 35 knots could support a few severe storms. In addition with PWAT values shown to be topping 1.75 inches, heavy downpours are likely to occur. Some training may occur as the boundary will be tracking only slowly south and east with time. Later tonight into Tuesday night, several weak waves of low pressure is shown to develop along this frontal zone from Missouri through Indiana and Ohio. This is largely in response to a digging mid level wave dropping southeast through the Upper Plains. This may support a risk for additional thunderstorms for far Southern Lower Michigan, thus we will hold onto some POPs then. .LONG TERM...(Wednesday night through Sunday) Issued at 210 AM EDT Mon Aug 6 2018 A series of mid level waves track southeast through the CWA Wednesday night into Thursday leading to a positively tilted trough axis through Lower Michigan on Thursday. Models are in relative agreement on this scenario. The combination of falling mid level heights and diurnal heating should support a few thunderstorms mainly for Thursday afternoon. Overall the trend is for keeping this trough around for the end of the week and into the weekend and eventually form it into a mid level low. This will act to keep temperatures relatively close to seasonable. We will need monitor this feature as its presence may also allow for a few diurnally driven showers/storms. && .AVIATION...(For the 12Z TAFS through 12Z Tuesday morning) Issued at 729 AM EDT Mon Aug 6 2018 Challenging aviation forecast. One round of storms moving in was largely dissipating. Another round is expected later this morning into the early afternoon hours. Then a third round is possible, mainly south of KGRR to KLAN this evening. Impacts look likely from any of the storms. Later tonight lower clouds are predicted to form with MVFR or lower possible. && .MARINE... Issued at 407 AM EDT Mon Aug 6 2018 A southwest flow today will veer to the north behind the front for Tuesday. Based on the mixing heights and forecasted winds, conditions are not expected to warrant any headlines. && .HYDROLOGY... Issued at 316 PM EDT Sun Aug 5 2018 River levels are running around to a little below normal for the time of year. Abnormally dry conditions continue over much of Lower Michigan, especially in the greater Lansing region and to the east and north. The U.S. Drought Monitor shows a moderate drought over that area. A cold front will move through the region tonight. Showers and thunderstorms will be possible into Tuesday, bringing locally heavy rain. Some ponding of water is possible, but the flood potential is low. && .GRR WATCHES/WARNINGS/ADVISORIES... MI...None. LM...None. && UPDATE...WDM SYNOPSIS...MJS SHORT TERM...MJS LONG TERM...MJS AVIATION...MJS HYDROLOGY...63 MARINE...MJS
Hazardous Weather Outlook National Weather Service Grand Rapids MI 446 AM EDT Mon Aug 6 2018 MIZ037>040-043>046-050>052-056>059-064>067-071>074-070900- Mason-Lake-Osceola-Clare-Oceana-Newaygo-Mecosta-Isabella-Muskegon- Montcalm-Gratiot-Ottawa-Kent-Ionia-Clinton-Allegan-Barry-Eaton- Ingham-Van Buren-Kalamazoo-Calhoun-Jackson- 446 AM EDT Mon Aug 6 2018 This hazardous weather outlook is for portions of southwest Lower Michigan. .DAY ONE...Today and Tonight A slight risk for severe thunderstorms exists along and south of a line from near Muskegon to Lansing, with a marginal risk further north. Damaging winds and large hail are the main severe weather risk. Any stronger storm could contain frequent lightning. Locally very heavy rain is forecast which could lead to urban, poor drainage and small stream flooding, especially where any storms persist. The main storm motion will be east at 35 mph. .DAYS TWO THROUGH SEVEN...Tuesday through Sunday Scattered thunderstorms are possible south of Interstate 96 on Tuesday. A few of these could contain gusty winds and frequent lightning along with locally heavy rainfall. Scattered thunderstorms are possible on Thursday. Severe weather is not forecasted at this time. .SPOTTER INFORMATION STATEMENT... Spotter activation may be needed into tonight. LMZ844>849-070900- 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- 446 AM EDT Mon Aug 6 2018 This hazardous weather outlook is for portions of southwest Lower Michigan. .DAY ONE...Today and Tonight Several rounds of thunderstorms are forecasted through tonight. Gusty winds, hail and frequent lightning may pose a risk to mariners. The primary storm motion will be east a 30 knots. .DAYS TWO THROUGH SEVEN...Tuesday through Sunday Scattered thunderstorms may pose a risk to mariners Tuesday and again on Thursday. .SPOTTER INFORMATION STATEMENT... Spotter activation may be needed into tonight.
Special Weather Statement National Weather Service Grand Rapids MI 825 AM EDT Mon Aug 6 2018 MIZ056>059-064>067-071>074-061430- Ottawa-Kent-Ionia-Clinton-Allegan-Barry-Eaton-Ingham-Van Buren- Kalamazoo-Calhoun-Jackson- 825 AM EDT Mon Aug 6 2018 ...SIGNIFICANT WEATHER ADVISORY... At 815 AM EDT, a line of thunderstorms stretched from Kalamazoo to Paw Paw. These storms were tracking east at 35 mph. They contain frequent lightning, gusty winds and locally heavy rainfall. Isolated stronger thunderstorms in this area will also be capable of producing hail up to the size of dimes...mainly south of Interstate 94. These storms will continue tracking east through 1000 am and will likely impact locations such as Kalamazoo...Battle Creek...Marshall and Charlotte. Scattered showers and thunderstorms were also indicated over Lake Michigan. This area of precipitation will move onshore...affecting the Grand Haven...Holland...Saugatuck and South Haven areas through 1000 am. Locally gusty winds to around 30 mph, frequent lightning and brief heavy rainfall rates that may top a half inch per hour may accompany the strongest storms. Isolated stronger storms could produce pea sized hail. MWS
Special Weather Statement National Weather Service Grand Rapids MI 928 AM EDT Mon Aug 6 2018 MIZ056>059-064>067-071>074-061530- Ottawa-Kent-Ionia-Clinton-Allegan-Barry-Eaton-Ingham-Van Buren- Kalamazoo-Calhoun-Jackson- 928 AM EDT Mon Aug 6 2018 ...SIGNIFICANT WEATHER ADVISORY... At 920 AM EDT, thunderstorms stretched from Lansing to Marshall. These storms were tracking northeast at 35 mph. They contain frequent lightning, gusty winds and locally heavy rainfall. Isolated stronger thunderstorms in this area will also be capable of producing hail up to the size of dimes. Locations along Interstate 69 between Tekonsha and Marshall and along Interstate 94 between Marshall and Jackson will be impacted by the stronger storms. These storms will continue tracking east through 1100 am. Scattered showers and thunderstorms were also along the Lake Michigan shore from Holland to South Haven. This area of precipitation will affect the Grand Haven...Holland...Saugatuck and South Haven areas through 1100 am. Locally gusty winds to around 30 mph, frequent lightning and brief heavy rainfall rates that may top a half inch per hour may accompany the strongest storms...especially along Interstate 196 near South Haven. Isolated stronger storms could produce pea sized hail. MWS
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE GRAND RAPIDS MI
1101 AM EDT MON AUG 6 2018
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
1100 AM HEAVY RAIN 4 SE GLENN 42.48N 86.17W
08/06/2018 M0.50 INCH ALLEGAN MI PUBLIC
&&
WDMPRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE GRAND RAPIDS MI
1256 PM EDT MON AUG 6 2018
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
1215 PM HEAVY RAIN 4 S PORT SHELDON 42.85N 86.20W
08/06/2018 E1.03 INCH OTTAWA MI MESONET
THE RAIN STARTED AROUND 5:05 AM, THEN
BETWEEN 6:45 AM AND 7:00 AM THERE WAS 0.39
INCHES. BY 9:20 AM ANOTHER .51 INCHES FELL
BRINGING THE TOTAL TO 0.90 INCHES. YET
ANOTHER SHOWER BETWEEN 11:45 AM AND 12:15 AM
BROUGHT THE OTHER 0.13 INCHES OF RAIN.
&&
WDMPRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE GRAND RAPIDS MI
1257 PM EDT MON AUG 6 2018
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
1215 PM HEAVY RAIN 4 S PORT SHELDON 42.85N 86.20W
08/06/2018 E1.03 INCH OTTAWA MI MESONET
THE RAIN STARTED AROUND 5:05 AM, THEN
BETWEEN 6:45 AM AND 7:00 AM THERE WAS 0.39
INCHES. BY 9:20 AM ANOTHER .51 INCHES FELL
BRINGING THE TOTAL TO 0.90 INCHES. YET
ANOTHER SHOWER BETWEEN 11:45 AM AND 12:15 AM
BROUGHT THE OTHER 0.13 INCHES OF RAIN.
&&Special Weather Statement
National Weather Service Grand Rapids MI
103 PM EDT MON AUG 6 2018
MIZ072-073-061800-
Kalamazoo MI-Calhoun MI-
103 PM EDT MON AUG 6 2018
...SIGNIFICANT WEATHER ADVISORY...
At 102 PM EDT, Doppler radar was tracking strengthening
thunderstorms along a line extending from Augusta to Schoolcraft.
Movement was east at 30 mph.
Dime size hail and winds in excess of 40 mph with downed tree limbs
will be possible with these storms.
Locations impacted include...
Portage... Albion... Marshall...
Battle Creek... Vicksburg... Galesburg...
Union City... Schoolcraft... Climax...
Burlington... Level Park-Oak Park... Brownlee Park...
Fulton... Marengo... Athens...
Augusta... Tekonsha... Pine Creek...
Bedford... Ceresco...
PRECAUTIONARY/PREPAREDNESS ACTIONS...
These storms may intensify, so be certain to monitor local radio
stations and available television stations for additional information
and possible warnings from the National Weather Service.
&&
LAT...LON 4207 8567 4242 8529 4242 8472 4229 8472
4207 8500
TIME...MOT...LOC 1702Z 275DEG 26KT 4233 8531 4211 8560
CASThe Grand Rapids radar (KGRR), 70 km away, was scanning. The volume nearest the first event began at 17:34 UTC.
2 thunderstorm wind. Local standard time, as filed.
The Calhoun county 911 call center reported that several reports of downed trees and power lines were received from across the county.
The Jackson county 911 call center reported that 3 trees were blown down in Spring Arbor and 1 was blown down in Concord.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Michigan in 2018Every state in 2018This day in weather historyWarnings in Michigan, August 2018
NOAA National Centers for Environmental Information, Storm Events Database, compiled from the National Weather Service’s monthly Storm Data. Complete through 2026-06; NCEI adds each month about 75 days after it ends and revises past years a few times a year. Rebuilt 2026-09-24. Each event’s entry at NCEI: 785814, 785815.