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Storm Prediction Center WCM Page
Intro | State Summaries | U.S. Annual Tornado Maps | 2014 Preliminary Reports to Date
Monthly Tornadoes Since 1950 | Bi-monthly Tornadoes by ENSO Phase Strength
Watch Frequency Maps | 20y Annual Average Watches by County | SPC AWIPS Products | Data | SVR GIS |
Warning Coordination Meteorologist's Introduction |
Welcome to the WCM Page for the SPC. This page has charts of the latest preliminary severe storm reports, annual summaries, and links to comma-separated-value (csv) data files from the SPC severe weather database back to 1950. As time allows, this page may occasionally serve as a place for preliminary severe weather event assessments.
Greg Carbin
Warning Coordination Meteorologist
NWS/NCEP Storm Prediction Center
July 17-18, 2015 Radar/Wind Gust Summary |
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Animated mosaic of radar images at the top of the hour showing evolution and track of severe storms from MN to MI Friday into Saturday, July 17-18, 2015.
| 2014 Preliminary Storm Reports |
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A preliminary look at all storm reports across the continental U.S. in 2014.
Full resolution map available here.
| SPC WCM Page Content Archive |
| Severe Weather Reports Per Year (2003-2012) |
These maps were created by gridding the total number of daily severe weather reports (Midnight to 11:59pm CDT) over the 10-year period from
2003 through 2012 on a 80km grid. The resulting grid numbers are then divided by 10 and smoothed to arrive at the annual average number of
days with a report of severe weather based on official NWS Storm Data records. The 80km grid-point value corresponds to the number of events within
25 miles of a point. While the resulting maps generally match our understanding of severe weather climatology, there are a few exceptions
that come about as a result of how the severe weather event is quantified. Even through the data are smoothed, severe weather reports cluster
around population centers. This can be seen on the "any" or "all" severe weather map in the upper left. Maximum values show up around Charlotte,
NC, Huntsville, AL, Jackson, MS, Springfield, MO, and Dallas, TX. These are locations where more severe weather is reported because more people
live in those areas. The hail reports used to generate the hail frequency map are from reports of hail 1 inch or greater in diameter. Large hail
reports are most common from Rapid City, SD to Denver, CO, Dodge City, KS, and Springfield, MO. The wind report map perhaps poses the greatest
challenge in terms of representing where a greater severe thunderstorm wind threat may exist. The majority of severe thunderstorm wind reports
are verified by falling trees *not* by observed wind gusts of 50 knots or greater. Thus, there is a distinct tendency for severe
thunderstorm winds to be reported in areas with more trees. Recent peer-reviewed studies have compared the severe weather reports used to make
these maps with automated observations (for wind), and radar data (for hail). These studies have found that greater concentrations/frequencies
of severe hail (based on radar) and 50kt or greater severe thunderstorm wind gusts (based on automated observations) are more likely to occur
over parts of the Great Plains and Midwest than what might be indicated in the maps shown here. (Click each map for full resolution version.)
References:
An Objective High-Resolution Hail Climatology of the Contiguous United States
John L. Cintineo, Travis M. Smith, Valliappa Lakshmanan, Harold E. Brooks, Kiel L. Ortega
Weather and Forecasting
Volume 27, Issue 5 (October 2012) pp. 1235-1248
Measured Severe Convective Wind Climatology and Associated Convective Modes of Thunderstorms in the Contiguous United States, 2003-09
Bryan T. Smith, Tomas E. Castellanos, Andrew C. Winters, Corey M. Mead, Andrew R. Dean, Richard L. Thompson
Weather and Forecasting (Also here.)
Volume 28, Issue 1 (February 2013) pp. 229-236
| Monthly Tornadoes by State |
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(Click on the maps to go to the maps page.)
| Annual Tornado Maps (1952-2011) |
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(Click on the maps to go to the Annual Tornado Maps page.)
| Annual Averages: Tornadoes by State |
| Annual Averages: Tornado Fatalities by State |
| Other U.S. Tornado Summaries |
| U.S. Monthly Tornado Counts, 1950-2010 |
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Monthly tornado sums (excluding (E)F0 tornadoes) for each month, 1950-2010.
(Click to go to calendar page.)
| Daily Counts and Annual Running Trend (Updated Frequently) |
| ENSO Strength and Bi-monthly U.S. Tornadoes since 1950 (Click link above to go to ENSO page.) |
| 2014 SPC Watch Frequency Maps |
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2014 Tornado and Severe Watch Count by County and Anomaly
(Click for full-resolution version.)
| 2013 SPC Watch Frequency Maps |
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2013 Tornado and Severe Watch Count by County and Anomaly
(Click for full-resolution version.)
| 2012 SPC Watch Frequency Maps |
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2012 Tornado and Severe Watch Count by County and Anomaly
(Click for full-resolution version.)
| 2011 SPC Watch Frequency Maps |
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2011 Tornado and Severe Watch Count by County and Anomaly
(Click for full-resolution version.)
| 2010 SPC Watch Frequency Maps |
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2010 Tornado and Severe Watch Count by County and Anomaly
(Click for full-resolution version.)
| 20y SPC Watch Climatology |
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Average number of tornado watches per year (1993-2012).
(Click for full-resolution version.)
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Average number of severe thunderstorm watches per year (1993-2012).
(Click for full-resolution version.)
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| SPC Tornado and Severe Weather Statistical Products on AWIPS |
Monthly Tornado Statistics are maintained in the AWIPS product STAMTS. Use this product to
find out how many tornadoes have occured so far this year and how
this year compares to past years.
Killer Tornado Statistics are listed in the AWIPS product STATIJ. Use this product for
information about killer tornadoes this year and in the past.
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Severe Weather Database Files (1950-2014) |
*** Annual csv file update occurred on March 17, 2015 ***
A few early tornado records have been added and/or corrected as part of the annual update to these files. If you use the tornado csv files in any application, it is recommended that you download the updated "All tornadoes in one zip file" from the link below the table and update your data accordingly.
*** Annual csv file update occurred on March 17, 2015 ***
The table below provides links to comma separated value (.csv) files for tornado, hail, and damaging wind data as compiled from NWS Storm Data.
Tornado reports exist back to 1950 while hail and damaging wind reports date from 1955. The full datasets are very large, especially hail and wind. To facilitate quicker downloads these data have been parsed by decade (1950s through 1990s), and half-decade, or less (from 2000 to the present).
Please read this document carefully as it describes the format of the .csv files (especially important for tornadoes!). Also note! The NWS changed Severe hail criteria from 0.75 inch minimum to 1.00 inch minimum in 2010. For legacy purposes, 0.75 inch hail reports will continue to be included in the latest hail csv files. Download the files and sort accordingly if needed.
It should also be noted that these data are used by the NWS for verification purposes and may not accurately reflect all storm events. Monetary loss information is highly suspect and should be used with caution, if at all. This article provides a good overview about the shortcomings in the NWS severe weather data provided here.
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All tornadoes in one 1.4 mb zip file. (Same as above for 1950-2014. *Updated March 17, 2015*)
All Off-CONUS tornadoes (AK, HI, PR) file. (These are not in other files!. *Updated April 13, 2015*)
All hail in one 5 mb zip file. (Same as above for 1955-2014. *Updated March 17, 2015*)
All wind in one 7 mb zip file. (Same as above for 1955-2014. *Updated March 17, 2015*)
Map of State FIPS Numbers here.
Text list of County FIPS Numbers here.
Better list of County FIPS Numbers (as xls file) here.
| SPC Severe GIS Page |
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U.S. map depicting tornado tracks and population density.
(Click to go to SPC Severe GIS Page.)
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