Organized deep convection plays a critical role in the global water cycle and drives extreme precipitation events tropical mid-latitude regions. However, simulating remains challenging for modern weather forecasts climate models due to complex interactions of processes from microscales mesoscales. Recent with kilometer-scale (km-scale) horizontal grid spacings (∆x) offer notable improvements compared coarser-resolution models. Still, deficiencies representing key physical...

Abstract Nocturnal mesoscale convective systems (MCSs) frequently develop over the Great Plains in presence of a nocturnal low-level jet (LLJ), which contributes to maintenance by providing source instability, convergence, and vertical wind shear. Although these MCSs often dissipate during morning, many persist into following afternoon despite cessation LLJ with onset solar heating. The environmental factors enabling postsunrise persistence convection are currently not well understood. A...

Abstract One of the most prolific tornado outbreaks ever documented occurred on 26–27 April 2011 and comprised three successive episodes tornadic convection that primarily impacted southeastern United States, including two quasi-linear convective systems (hereinafter QLCS1 QLCS2) preceded notorious outbreak long-track, violent tornadoes spawned by numerous supercells afternoon 27 April. The ∼36-h period encompassing these was part a longer multiday ahead slowly moving upper-level trough over...

Abstract The maximum upward vertical velocity at the leading edge of a density current is commonly <10 m s −1 . Studies velocity, however, are relatively few, in part owing to dearth high-spatiotemporal-resolution observations. During Plains Elevated Convection At Night (PECAN) field project, mobile Doppler lidar measured 13 created by mesoscale convective system during night 15 July 2015. Two other vertically pointing instruments recorded 8 velocities on same night. This study describes...

Abstract One of the most prolific tornado outbreaks ever documented occurred on 26–27 April 2011 and comprised three successive episodes tornadic convection that culminated with development numerous long-track, violent tornadoes over southeastern United States during afternoon 27 April. This notorious supercell outbreak was preceded by two quasi-linear convective systems (hereinafter QLCS1 QLCS2), first which an anomalously severe nocturnal system rapidly grew upscale previous evening. Here...

Ertel’s potential vorticity (PV) is an important quantity in atmospheric dynamics that succinctly encompasses the principles of mass, momentum, and energy conservation applicable to all scales motion. In this paper, we describe implementation a PV diagnostics package into component Model for Prediction Across Scales (MPAS), fully compressible nonhydrostatic global model enables regional mesh refinement convection-permitting resolutions highly suited studies on multiscale process interactions...

Abstract A 50-member convection-allowing ensemble was used to examine environmental factors influencing afternoon convection initiation (CI) and subsequent severe weather on 5 April 2017 during intensive observing period (IOP) 3b of the Verification Origins Rotation in Tornadoes Experiment Southeast (VORTEX-SE). This case produced several weak tornadoes (rated EF1 or less), numerous reports significant hail (diameter ≥ 2 in.; ≥~5 cm), ahead an eastward-moving surface cold front over eastern...