Damaging Winds of April 19, 2020

Damaging Straight-line Winds on April 19, 2020

A low-amplitude trough affected the Gulf Coast region April 19th & 20th, with Central Alabama impacts consisting of two instances of significant straight-line wind events (resulting in injuries), alongside large hail & flash flooding. This activity was focused south of Interstate 20.

During the morning of the 19th, a warm front was located along the immediate Gulf Coast, placing all of Central Alabama in an environment consisting of a stable low-level air mass; however, there was plenty of wind shear & instability aloft to support the development of elevated thunderstorms (some severe) associated with a lead impulse. After a midday break, a second round occurred late afternoon through the evening hours as the warm front struggled to move northward. Additional severe thunderstorms & flooding occurred.

Chilton, Coosa & Tallapoosa Counties

Rating: (Click for EF Scale)	N/A
Estimated Maximum Wind:	70-90 mph
Injuries/Fatalities:	3 Injuries
Damage Path Length:	~65 miles
Maximum Path Width:	~6 miles
Approximate Start Point/Time:	Near Thorsby at 618 am
Approximate End Point/Time:	Near Dadeville

The core of a potent thunderstorm quickly intensified in the vicinity of Interstate 65 in Chilton County during the early-morning hours. Large hail to around golf ball size resulted from this cell, with significant straight-line wind developing as the core dump breached the low-level stable layer.

Extensive wind damage began in Chilton County (just west of Thorsby & Jemison) where maximum winds were estimated in the range of 80 to 90 MPH. The wind damage continued eastward through Coosa County & Tallapoosa County, where maximum winds were estimated in the range of 70 to 80 MPH. The damage, as confirmed by a NWS survey team, was the result of straight-line wind consisting of (1) numerous snapped & uprooted hardwood/softwood trees, (2) tree fall onto structures, (3) tree fall onto campers, especially notable in Wind Creek State Park where several were crushed, (4) damage to roofs, siding, overhangs, awnings, outbuildings and, (5) a case of wind-driven hail causing severe exterior damage to buildings in the Kellyton area of Coosa County. Wind damage became less intense & more sporadic as the storm entered Chambers County. At least 3 injuries were reported, all in Tallapoosa County.

View larger map

Radar Data

This is an image of the 0.5 degree reflectivity (left) and velocity (right) data from KBMX Radar at 639 am. The imagery shows the bowing segment associated with straight-line winds moving through western Coosa County.

Pike & Barbour Counties

Rating: (Click for EF Scale)	N/A
Estimated Maximum Wind:	85-95 mph
Injuries/Fatalities:	None
Damage Path Length:	~60 miles
Maximum Path Width:	~11 miles
Approximate Start Point/Time:	Near Goshen at 1049 pm
Approximate End Point/Time:	Near the AL/GA state line

A line of thunderstorms began to gain organization & intensity over Butler & Crenshaw Counties (as well as points south) as they moved eastward. The reflectivity gradient on these storms steadily sharpened, with a significant & persistent straight-line wind signature developing thereafter per wind velocity data. Extensive wind damage began in Crenshaw County (and points south), served by NWS Mobile, and then translated through Pike & Barbour Counties, served by NWS Birmingham. A large swath of straight-line wind damage, as confirmed by a NWS survey team, occurred in the southern portion of Pike & Barbour Counties consisting of (1) numerous snapped & uprooted hardwood/softwood trees, (2) tree fall onto structures and, (3) damage to roofs, siding, overhangs, and outbuildings. Seemingly, the most significant damage was along a stretch from Goshen to Brundidge. These storms continued into Georgia, producing additional damage.

View larger map

Radar Data

This is an image of the 0.5 degree reflectivity (left) and velocity (right) data from KEOX Radar at 1109 pm. The imagery shows the bowing segment associated with damaging straight-line winds about to cross Hwy 231 near Brundidge.