High-Based T'Storms of April 8, 2020
A band, a bow in the far south & a southern half supercell produced severe weather 7-8:30 p.m.
Temperatures reached 75-83 during the day, but dew points dropped to the 30s to 50 prior to the storms.
With steep lapse rates with the cold air aloft, strong wind fields & shear & upper trough (& very sharp height falls & sharp surface cold front), storms blossomed with high bases due to the dry, dry air near the surface. Such a scenario is more common in the drier High Plains from western Texas & Oklahoma to eastern Montana & North Dakota than here.
Very strong to severe gusts reached the surface with the rainfall & t'storms due to the dry air.
Some minor damage to rooftops & trees occurred.
The strongest wind gust in the area was measured near Thorntown with a measured gust of 75 mph with shingle & tree damage. Trees & powerlines were reported down across Carroll County. One tree fell over a drive way near Battle Ground. A large limb fell from a tree at Otterbein. Multiple power outages occurred in the area.
Hail covered the ground like snow in a discontinuous band from West Lebanon to north of Darlington.
Hail up to 1-1.50" occurred in this band.
The intensity of the storms & damage increased south & southeast of our area as dew points rose (along with more surface CAPE), but our dry surface & low levels wedged a few thousand feet up in those areas. This enhanced gusts, which reached near 90 mph in places. Shear & higher CAPE near/at the surface also produced one tornado (EF1 southwest of Indianapolis).
W = wind damage or measured gust 58 mph or greater
H = hail 1" in diameter or larger
T = Tornado
These are the actual measured gusts & estimated gusts based on damage or what spotters estimated that reached or exceeded 45 mph (I did include 60 mph Purdue Airport gust & our 54 mph gust as it occurred during rain & thunder. I think the 60 mph gust in NWS LSR was labeled "Non-T'Storm Wind Gust":
All hail reports (even sub-severe):
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July 11, 2020 Severe Storm Cluster
The second round (Saturday night 10 p.m.-2 a.m.) looked the worst in the Saturday morning data, compared to the first round forecasted (3-6 p.m.)
However, the first ended up being the worst. It was small & compact, but potent MCV that triggered this storm cluster. The environment downstream was unstable with plenty of rapid heating underway with a steep lapse. Up to 40 knots of Effective Shear accompanied the MCV.
A cluster of severe storm develop with a comma head shape with the main severe storm being a large node in the head of that.
A corridor of tree, crop, powerline & some structural damage occurred with the storm. Hail was all sub-severe at 0.75" or less, but the severe winds & sheer amount of hail caused considerable crop damage & tree foliage shredding.
The worst damage appears to have occurred with two microbursts. One occurred just southeast of Brookston with +70 mph gusts with heavy tree, powerline & crop damage & damage to a barn. The other was near & southeast of Rossville with heavy tree, powerlines & crop damage. A home was also unroofed from +70 mph gusts.
A few limbs & trees were blown down on the north side of Lafayette, while one large tree was uprooted near New Market.
0.5" hail was measured northeast of Attica.
By the time the bow of storms with widespread wind damage in Illinois arrived Saturday night, we were stabilized & had been overturned by earlier storm too much for much severe weather. That all occurred in Illinois & to southwestern Indiana.
W = wind damage or measured gust 58 mph or greater
H = hail 1" in diameter or larger
T = Tornado
These are the actual measured gusts (at or above 45 mph) & estimated gusts based on damage or what spotters estimated:
All hail reports (even sub-severe):
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July 19, 2020 Bowing Semi-Organized MCS
Semi-organized MCS passed just after midday to early afternoon with overnight lows only around 80 & dew points ahead of the complex of storms to 80.
Damaging winds occurred with apex of bow with peak gust of 86 mph measured northeast of Rensselaer.
Lack of better shear & some struggling from capping in our southern areas resulted in lack of the best organization & less widespread severe gusts.
W = wind damage or measured gust 58 mph or greater
H = hail 1" in diameter or larger
T = Tornado
These are the actual measured gusts (at or above 45 mph) & estimated gusts based on damage or what spotters estimated:
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July 21, 2020 Bowing Compact MCS
Bowing MCS, which developing on MCV from MCS in Missouri, Kansas the night before, brought a discontinuous swath of damaging straight-line winds right through the heart of the viewing area.
Trees, limbs & powerlines were reportedly downed in parts of northern Warren, northeastern Fountain, Tippecanoe & Miami counties. One tree was toppled at Brookston, while another tree was felled by the wind near Oxford.
A Tornado Warning was issued for a tight notch & node in the line that tracked from near Veteran's & 18th through areas north of Subaru to north of Dayton & south of Monitor.
Tree damage & some minor structural damage was found, but it was all of the straight-line wind nature. No tornadic wind damage was found, nor any tornado track through any fields.
W = wind damage or measured gust 58 mph or greater
H = hail 1" in diameter or larger
T = Tornado
These are the actual measured gusts (at or above 45 mph) & estimated gusts based on damage or what spotters estimated:
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August 10, 2020 Serial Derecho
Wind damage or severe gusts were reported in every county of the viewing area from this Serial Derecho.
This was also the first Storm Prediction Center-issued PDS watch (PDS or Particularly Dangerous Situation Severe Storm Watch for Newton, Jasper & Benton counties) since a PDS Severe T'Storm Watch in the June 22-23, 2016 nocturnal Serial Derecho. Prior to this, the last PDS watch was the PDS Tornado Watch on November 17, 2013 for that historic tornado outbreak.
The worst of the winds (80-115 mph) occurred northwest & just north of our area (with multiple brief EF0-EF1 spin-ups), but winds here were generally 50-80 mph. Highest gusts appear to have occurred just north of Kentland & in far northern Jasper County near the Kankakee River.
The main area of minor structural damage was northwest & north of Kentland with metal farm building damage & shingles off homes. Shingles were also reportedly blown off some homes near Battle Ground & in Carroll County.
The derecho raced through the area in the 5:15-7 p.m. time frame & was basically in & out with a forward speed of up to 70 mph.
The highest dew points of 2020 at 77-82 area-wide occurred ahead of it with temperatures of 86-93. This resulted in heat indices of 97-115. A large area from southern to central & north-central Illinois saw heat indices reach or exceed 110 as 80-degree dew points pooled.
Pic from Shelby Anderson in Lafayette:
W = wind damage or measured gust 58 mph or greater
H = hail 1" in diameter or larger
T = Tornado
These are the actual measured gusts (at or above 45 mph) & estimated gusts based on damage or what spotters estimated:
All hail reports (even sub-severe):
Map up soon
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