The IEM has a database archive of SPC MCDs since 2003. The download offered here does not contain the MCD text discussion, but the polygon geometry along with some metadata. The backend database that services this download updates in realtime, so the data should be as current as your download.
Backend DocumentationRelated Services
Shapefile DBF Schema
| Field | Type | Title | Description |
|---|---|---|---|
| 0 | String | ISSUE | UTC Issuance Timestamp YYYYmmddHHMM |
| 1 | String | EXPIRE | UTC MCD Expiration Timestamp |
| 2 | String | PROD_ID | IEM Product ID (see below) |
| 3 | Double | YEAR | YEAR of MCD |
| 4 | Double | NUM | SPC MCD Number |
| 5 | Double | CONFIDEN | SPC Watch issuance confidence |
| 6 | String | CONCERN | SPC MCD concerning heading |
| 7 | String | MP_TORN | SPC MCD Most Probable Tornado Intensity |
| 8 | String | MP_HAIL | SPC MCD Most Probable Hail Intensity |
| 9 | String | MP_GUST | SPC MCD Most Probable Gust Intensity |
Archive / Usage Notes
API Integration: The
PROD_ID DBF field is a string the IEM uses to identify
NWS Text products and can be used to call an IEM API to fetch the text of
this product: https://mesonet.agron.iastate.edu/api/1/nwstext/{PROD_ID}
SPC Integration: The
YEAR and NUM fields can be used to construct
a stable URL into SPC's website like so: https://www.spc.noaa.gov/products/md/{year}/md{NUM:04i}.html