Identification

Title

The merger of a supercell and squall line in the Great Plains: 2. Formation of a bow echo

Abstract

The merger of squall line and supercell has been commonly observed in the Great Plains of the United States. On 23–24 May 2020, an isolated supercell formed ahead of a squall line and subsequently evolved into a bow echo through their merger. Utilizing a 10‐min update four‐dimensional variational data assimilation system that integrates radar and surface observations, we investigated the convective‐scale processes that led to the formation of this bow echo. Our findings indicated that as the squall line advanced eastward, its inflow was initially obstructed by the supercell, causing the weakening of both the squall line and its associated cold pool. However, during the merger, a strong rear inflow jet (RIJ) rapidly developed ahead of the squall line's leading edge and behind the supercell. Unlike a classic RIJ that typically expands rearward over the cold pool, this RIJ accelerated forward toward the supercell. Diagnostic pressure analysis revealed that the RIJ was primarily driven by the developing mesolow embedded within the supercell. Additionally, the supercell's strengthening prior to bowing generated a deep‐tropospheric gravity wave downdraft, which amplified the RIJ by enhancing near‐surface westerlies. Despite the weakening of the squall line's cold pool, it still contributed to the RIJ formation by providing negative horizontal vorticity at its leading edge and facilitating the RIJ's descent. Consequently, the intense RIJ and the subsequent replacement of the supercell against the initial leading edge led to the formation of a severe bow echo, producing a broad swath of damaging winds.

Resource type

document

Resource locator

Unique resource identifier

code

https://n2t.net/ark:/85065/d7m90f3j

codeSpace

Dataset language

eng

Spatial reference system

code identifying the spatial reference system

Classification of spatial data and services

Topic category

geoscientificInformation

Keywords

Keyword set

keyword value

Text

originating controlled vocabulary

title

Resource Type

reference date

date type

publication

effective date

2016-01-01T00:00:00Z

Geographic location

West bounding longitude

East bounding longitude

North bounding latitude

South bounding latitude

Temporal reference

Temporal extent

Begin position

End position

Dataset reference date

date type

publication

effective date

2025-07-16T00:00:00Z

Frequency of update

Quality and validity

Lineage

Conformity

Data format

name of format

version of format

Constraints related to access and use

Constraint set

Use constraints

Limitations on public access

None

Responsible organisations

Responsible party

contact position

OpenSky Support

organisation name

UCAR/NCAR - Library

full postal address

PO Box 3000

Boulder

80307-3000

email address

opensky@ucar.edu

web address

http://opensky.ucar.edu/

name: homepage

responsible party role

pointOfContact

Metadata on metadata

Metadata point of contact