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2. Top 10 SPC Outlooks by size

Top 10 SPC Outlooks by Size

The IEM attempts a robust archive of SPC outlooks. These outlooks have changed methodologies and threshold meanings over the years. You are strongly encouraged to set a start year to limit the data to a given period. The listing only inludes one outlook for a given canonical date.

This app can be slow to generate! For common outlook types, the backend database query can take a number of seconds to complete. The computed area is done within the US National Atlas Equal Area (EPSG:9311).

Related: Top 10 MCDs by Size SPC Outlook Shapefile Download

Inclusive Start Year: 198719881989199019911992199319941995199619971998199920002001200220032004200520062007200820092010201120122013201420152016201720182019202020212022202320242025

Select Day: Day 1 Day 2 Day 3 Day 4 Day 5 Day 6 Day 7 Day 8

Select Threshold: Any Severe 2% (Day 3+) Any Severe 5% (Day 3+) Any Severe 15% (Day 3+) Any Severe 25% (Day 3+) Any Severe 30% (Day 3+) Any Severe 35% (Day 3+) Any Severe 45% (Day 3+) Any Severe 60% (Day 3+) Any Severe Significant (Day 3+) Categorical Thunderstorm Risk (Days 1-3) Categorical Marginal Risk (2015+) (Days 1-3) Categorical Slight Risk (Days 1-3) Categorical Enhanced Risk (2015+) (Days 1-3) Categorical Moderate Risk (Days 1-3) Categorical High Risk (Days 1-3) Hail 5% (Days 1+2) Hail 15% (Days 1+2) Hail 25% (Days 1+2) Hail 30% (Days 1+2) Hail 35% (Days 1+2) Hail 45% (Days 1+2) Hail 60% (Days 1+2) Hail Significant (Days 1+2) Tornado 2% (Days 1+2) Tornado 5% (Days 1+2) Tornado 10% (Days 1+2) Tornado 15% (Days 1+2) Tornado 25% (Days 1+2) Tornado 30% (Days 1+2) Tornado 35% (Days 1+2) Tornado 45% (Days 1+2) Tornado 60% (Days 1+2) Tornado Significant (Days 1+2) Wind 5% (Days 1+2) Wind 15% (Days 1+2) Wind 25% (Days 1+2) Wind 30% (Days 1+2) Wind 35% (Days 1+2) Wind 45% (Days 1+2) Wind 60% (Days 1+2) Wind Significant (Days 1+2)

Top 10 Largest Day: 3 Category: CATEGORICAL Threshold: ENH

Generated at: 2025-03-21T05:11:26Z in 0.14s

JSON Webservice for the data below:
https://mesonet.agron.iastate.edu/json/spc_bysize.py?day=3&threshold=ENH&category=CATEGORICAL&syear=1987

Rank	Canonical Outlook Date	Cycle Hour UTC	Size (sq km)	SPC Link/Image
1	2022-04-13	8	614243.56
2	2023-03-31	8	576472.87
3	2024-05-08	8	539336
4	2025-03-14	20	463326.85
5	2020-04-12	8	456744.96
6	2015-05-16	8	404365.22
7	2025-03-15	20	375780.16
8	2017-05-27	8	371285.87
9	2023-04-04	8	366809.11
10	2020-04-19	8	365042.99