Campus Units

Geological and Atmospheric Sciences

Document Type

Article

Publication Version

Published Version

Publication Date

8-2017

Journal or Book Title

Weather and Forecasting

Volume

32

Issue

4

First Page

1613

Last Page

1635

DOI

10.1175/WAF-D-16-0222.1

Abstract

The prediction of convective initiation remains a challenge to forecasters in the Great Plains, especially for elevated events at night. This study examines a subset of 287 likely elevated nocturnal convective initiation events that occurred with little or no direct influence from surface boundaries or preexisting convection over a 4-month period of May–August during the summer of 2015. Events were first classified into one of four types based on apparent formation mechanisms and location relative to any low-level jet. A climatology of each of the four types was performed focusing on general spatial tendencies over a large Great Plains domain and initiation timing trends. Simulations from five convection-allowing models available during the Plains Elevated Convection At Night (PECAN) field campaign, along with four versions of a 4-km Weather Research and Forecasting (WRF) Model, were used to examine the predictability of these types of convective initiation. A dual-peak pattern for initiation timing was revealed, with one peak near 0400 UTC and another around 0700 UTC. The times and prominence of each peak shifted depending on the region analyzed. Positive thermal advection by the geostrophic wind was present in the majority of events for three types but not for the type occurring without a low-level jet. Models were more deficient with location than timing for the five PECAN models, with the four 4-km WRF Models showing similar location errors and problems with initiating convection at a lower altitude than observed.

Comments

This article is published as Stelten, Sean, and William A. Gallus Jr. "Pristine nocturnal convective initiation: A climatology and preliminary examination of predictability." Weather and Forecasting 32, no. 4 (2017): 1613-1635. DOI: 10.1175/WAF-D-16-0222.1. Posted with permission.

Copyright Owner

American Meteorological Society

Language

en

File Format

application/pdf

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