Identification

Title

Next-day prediction of tornadoes using convection-allowing models with 1-km horizontal grid spacing

Abstract

Explicit attributes of convective storms within convection-allowing model (CAM) forecasts are routinely used as surrogates for convective weather hazards. The ability of 3- and 1-km horizontal grid spacing CAM forecasts to anticipate tornadoes using surrogates was examined for 497 severe weather events. Five diagnostics were used as tornado surrogates, including 0–1 km above ground level (AGL) updraft helicity (UH01), 2–5 km AGL UH (UH25), 0–3 km AGL UH (UH03), and 500 m and 1 km AGL relative vorticity. Next-day surrogate severe probability forecasts (SSPFs) for tornadoes were produced by thresholding the diagnostics and smoothing the resulting binary field. SSPFs were verified against SPC tornado reports and NWS tornado warnings. The 1-km SSPFs were more skillful than 3-km SSPFs across all diagnostics with statistically significant differences in skill that were largest on the mesoscale. UH01 outperformed the other four diagnostics, in part because UH01 best represented regional variations in observed tornado report totals. Filtering forecasts based on the significant tornado parameter benefited the 3-km SSPFs much more than the 1-km SSPFs, with filtered 3-km SSPFs having similar skill to the filtered 1-km SSPFs. SSPFs verified with a combination of tornado warnings and reports were more skillful than when verified against reports alone, indicating that CAMs can better predict intense low-level rotation events than tornadoes. When verifying all severe hazards, UH25 SSPFs were more skillful than UH01 SSPFs; UH01 and UH25 appear to be the most useful pair for anticipating tornadoes and the combined severe threat on a given forecast day.

Resource type

document

Resource locator

Unique resource identifier

code

http://n2t.net/ark:/85065/d7s46tq8

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

2019-08-01T00:00:00Z

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