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Warning Decision Training Division
Professional Development Series

Severe Convection Forecasting and Warnings

PCU 2: Assessing Climatology

Producer: TBD


Click here first for an Introduction



Specific Job Task Skills and Knowledge:

Task 2.1: Each office should designate a Focal Point to ensure a local severe weather climatology is developed, updated, and easily accessible to forecasters.

Task 2.2: The Focal Point should develop unique local cases or create other exercises that allow forecasters to demonstrate their knowledge of local effects on severe convection.

Task 2.3: Monitor SPC's Severe Weather Reports "rough" log and Convective Outlook during severe weather events to determine the potential evolution and intensity of developing severe weather.

Current SPC Day One
Current SPC Storm
SPC Day One Convective Outlook
SPC Storm Reports

Instructional Components:

IC 2.1: Use the content below to assist in creating or updating your local severe weather and/or convective climatology.

Suggested Content for a Local Climatological Database:

All Severe
  • Period of record totals, events, and days
  • Seasonal, monthly, daily, and hourly distributions
  • Spatial distribution over the desired area
Yearly SPC Storm Reports
  • Frequency and total of tornadoes by EF-scale
  • Spatial and temporal distribution of all tornadoes
  • Temporal distribution of significant tornadoes
    (EF-2 / F-2 or greater) and/or killer tornadoes
  • Spatial and temporal frequency and distribution of hail (NOTE: Hail criterion for SVR warnings has changed to 1.00 inch as of January 5, 2010. Click here to find out more about the change.)
  • Temporal distribution of large hail (≥ 2" diameter)
  • Spatial and temporal distribution of high wind reports
  • Temporal distribution of significant wind reports
    (≥ 65 kts)
Flash Flood
  • Frequency and/or return period of floods/flash floods for particular (or all) waterways or basins
  • Precipitation frequency analysis for various temporal periods
Flash Flood
  • Spatial and temporal distribution of cloud-to-ground (CG) lightning
  • Gridded flash densities per temporal period
  • Spatial distribution of CG lightning based on synoptic flow regimes
Lightning Climatology

Climatological Information Sources and Tools:

Storm Prediction Center

The Storm Prediction Center (SPC) maintains a historical Online Archive of tornado, hail, and damaging wind occurrence dating back to the 1950s. The zipped comma-delimited files can be downloaded for creation of a local climatology. The SPC also has a GIS-based web page where you can download the shapefiles for tornado, hail, and wind reports dating back to 1955 (1950 for tornadoes).

New: SPC Tornado Environment Browser

NWS Verification Page

The NWS Verification Page, a product from the Performance Branch, allows the user to search for and download severe weather events and their associated warnings using a query-type feature. Online verification data date back to January 1986.

ArcGIS & Google Earth

New software, such as ArcGIS and Google Earth, allows for severe weather events to be plotted against other geo-spatial data. These programs provides the ability to overlay meteorological data with high-resolution satellite images, road networks, and population densities. Statistical analysis can be performed within the ArcGIS software through spatial analysis tools.

Hydrometeorology Material

Monthly Precipitable Water Climatology:

Precipitation Frequency Analysis created by the NOAA NWS Hydrometeorological Design Studies Center (New and Incomplete)

NCDC Heavy Rainfall Frequencies for the U.S.

Technical Paper #40: Rainfall Frequency Atlas of the United States for Durations from 30 Minutes to 24 Hours and Return Periods from 1 to 100 Years (1961)

Standardized Anomalies

Standardized anomalies can help provide a way to synoptically analyze the magnitude of an event when compared to a climatological normal. Here are some links to help create anomaly plots:

IC 2.2: Understand the estimated severe weather potential for your area using the Severe Thunderstorm Climatology (using data up to 1999) from the National Severe Storms Laboratory (NSSL) and the Monthly and Annual U.S. Severe Weather Summaries (2000 to present) from the Storm Prediction Center (SPC).

References and Examples:

Example Climatologies

"A Severe Weather Climatology for the WFO Blacksburg, Virginia, County Warning Area" by Robert C. Stonefield and James E. Hudgins (NOAA/NWS WFO-Blacksburg, Virginia)

"Severe Weather Climatology for MPX" - A PDF created by the NOAA/NWS WFO-Minneapolis, Minnesota

"Cool Season Tornadoes in the Southeast U.S." - A powerpoint created by Steven Nelson and Stephen Konarik (NOAA/NWS WFO-Peachtree City, Georgia)

"The Tornado Climatology of the NWS St. Louis County Warning Area" and how it was created by the NOAA/NWS WFO-St. Louis, Missouri

"A Brief Climatology of Significant Hail in Missouri and Illinois" by Mark F. Britt (NOAA/NWS WFO-St. Louis, Missouri)

"Iowa Tornado Climatology from 1980-2008" by Craig Cogil (NOAA/NWS WFO-Johnston, Iowa)

"Tornado Facts and Graphs for Southern Indiana and Central Kentucky: 1830 to Present" by the NOAA/NWS WFO-Louisville, KY


We would like to thank all of the following personnel and offices for their input into this section of the Professional Development Series:

FSU Department of Meteorology: Scott Rudlosky and Dr. Henry Fuelberg
WFO - Blacksburg: Stephen Keighton, Phil Hysell, Robert Stonefield, and James Hudgins
WFO - Minneapolis: Tom Hultquist
WFO - Peachtree City: Steven Nelson and Stephen Konarik



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