The Tornado Alley is a geographic region in central United States that is home to the largest number of violent tornadoes in the world. The cloud structures that produce the most violent tornadoes are known as supercells. Being able to predict the formation and the evolution of supercell thunderstorms can improve the forecasting of such severe weather events, thereby preventing human and resour...

We identify mechanisms controlling the distribution of methane convection and large-scale circulation in a simplified, axisymmetric model atmosphere of Titan forced by gray radiation and moist (methane) convection. The large-scale overturning circulation, or Hadley cell, is global in latitudinal extent and provides fundamental control of precipitation and tropospheric winds. The precipitating, ...

The efficacy of three suction traps for trapping phlebotomine sand flies (Diptera: Psychodidae) was compared. Traps were baited with Co(2) and used without any light source. CO(2)-baited CDC traps were evaluated either in their standard downdraft orientation or inverted (iCDC traps). Mosquito Magnet-X (MMX) counterflow geometry traps were tested in the updraft orientation only. Both updraft tra...

Updraft speeds of thermals have always been difficult to measure, despite the significant role they play in transporting pollutants and in cloud formation and precipitation. In this study, updraft speeds in buoyancydriven planetary boundary layers (PBLs) measured by Doppler lidar are found to be correlated with properties of the PBL and surface over the Southern Great Plains (SGP) site operated...

A three-dimensional nonhydrostatic numerical model, the Advanced Regional Prediction System, is used to study the process of cyclic mesocyclogenesis in a classic supercell thunderstorm. During the 4-h simulation, the storm’s mesocyclone undergoes two distinct occlusions, with the beginning of a third indicated at the end of the simulation. The occlusion process exhibits a period of approximatel...

We have investigated the formation of cloud droplets under pyro-convective conditions using a cloud parcel model with detailed spectral microphysics and with the κ-Köhler model approach for efficient and realistic description of the cloud condensation nucleus (CCN) activity of aerosol particles. Assuming a typical biomass burning aerosol size distribution (accumulation mode centred at 120 nm), ...

TheAdvanced Regional Prediction System (ARPS) is used to simulate a tornadic mesovortex with the aim of understanding the associated tornadogenesis processes. The mesovortex was one of two tornadic mesovortices spawned by a mesoscale convective system (MCS) that traversed southwestern and central Oklahoma on 8–9 May 2007. The simulation used 100-m horizontal grid spacing, and is nested within t...

The rapid glaciation of tropical cumulus clouds has been an enigma and has been debated in the literature for over 60 years. Possible mechanisms responsible for the rapid freezing have been postulated, but until now direct evidence has been lacking. Recent high-speed photography of electrostatically suspended supercooled drops in the laboratory has shown that freezing events produce small secon...

33 34 The ARPS model is used to simulate a tornadic mesovortex with the aim of 35 understanding the associated tornadogenesis processes. The mesovortex was one of two tornadic 36 mesovortices spawned by a mesoscale convective system (MCS) that traversed southwest and 37 central Oklahoma on 8-9 May 2007. The simulation used 100-m horizontal grid spacing, and is 38 nested within two outer grids w...