![Sample of [paragraphs_item:field-grid-block-link:title]](https://webarchive.library.unt.edu/web/20170119052355im_/https://www.drought.gov/drought/sites/drought.gov.drought/files/styles/grid_thumbail/public/externals/0e2234aaa95b4f409d2b70cbb0fe3e83.png?itok=XKTwRgB-)
![Sample of [paragraphs_item:field-grid-block-link:title]](https://webarchive.library.unt.edu/web/20170119052355im_/https://www.drought.gov/drought/sites/drought.gov.drought/files/styles/grid_thumbail/public/externals/b7233dca7fb67be84490eb3a00acadd0.png?itok=aRKk-ljA)
![Sample of [paragraphs_item:field-grid-block-link:title]](https://webarchive.library.unt.edu/web/20170119052355im_/https://www.drought.gov/drought/sites/drought.gov.drought/files/styles/grid_thumbail/public/externals/ab9e3551bc68024aa614d81aafb253e6.gif?itok=vbtlWIxT)
The PDSI represents drought severity, framed from the perspective of soil moisture or dryness. The Palmer metrics are computed based upon a location’s recent precipitation, recent atmospheric evaporative demands, and its soil characteristics.
![Sample of [paragraphs_item:field-grid-block-link:title]](https://webarchive.library.unt.edu/web/20170119052355im_/https://www.drought.gov/drought/sites/drought.gov.drought/files/styles/grid_thumbail/public/externals/569e7185e62cd9581f2933370e4a2b23.png?itok=rsWrc5-T)
![Sample of [paragraphs_item:field-grid-block-link:title]](https://webarchive.library.unt.edu/web/20170119052355im_/https://www.drought.gov/drought/sites/drought.gov.drought/files/styles/grid_thumbail/public/externals/264dd6a7028f8f62b203813c5c780836.png?itok=pXa781yL)
![Sample of [paragraphs_item:field-grid-block-link:title]](https://webarchive.library.unt.edu/web/20170119052355im_/https://www.drought.gov/drought/sites/drought.gov.drought/files/styles/grid_thumbail/public/externals/b417665ea7e6893b8a802e84ba8f89ce.png?itok=SYe0Lt4O)
![Sample of [paragraphs_item:field-grid-block-link:title]](https://webarchive.library.unt.edu/web/20170119052355im_/https://www.drought.gov/drought/sites/drought.gov.drought/files/styles/grid_thumbail/public/externals/441a898aa7ece5cce2ecbcd9be81d962.png?itok=BucXyAek)
![Sample of [paragraphs_item:field-grid-block-link:title]](https://webarchive.library.unt.edu/web/20170119052355im_/https://www.drought.gov/drought/sites/drought.gov.drought/files/styles/grid_thumbail/public/externals/a484d270c57979d7b8fddde548ba6588.png?itok=sLskXhxb)
![Sample of [paragraphs_item:field-grid-block-link:title]](https://webarchive.library.unt.edu/web/20170119052355im_/https://www.drought.gov/drought/sites/drought.gov.drought/files/styles/grid_thumbail/public/externals/2fc3adaa8ac1477af9239f667ae13d64.png?itok=jelxyeNT)
![Sample of [paragraphs_item:field-grid-block-link:title]](https://webarchive.library.unt.edu/web/20170119052355im_/https://www.drought.gov/drought/sites/drought.gov.drought/files/styles/grid_thumbail/public/externals/2e29d1a3e9b665176429be89a61e5c9c.png?itok=XPJIujo_)
The Standardized Precipitation-Evapotranspiration Index (SPEI) indicates how unusual a combination of precipitation and evapotranspiration (the atmospheric demand for water) is, compared to the historical record over a given time scale.
![Sample of [paragraphs_item:field-grid-block-link:title]](https://webarchive.library.unt.edu/web/20170119052355im_/https://www.drought.gov/drought/sites/drought.gov.drought/files/styles/grid_thumbail/public/externals/503dcd580bba3ca592ff1b922afa0e60.png?itok=O0ahcHBA)
![Sample of [paragraphs_item:field-grid-block-link:title]](https://webarchive.library.unt.edu/web/20170119052355im_/https://www.drought.gov/drought/sites/drought.gov.drought/files/styles/grid_thumbail/public/externals/1c61d448d2876af6f48433ffbb24b806.png?itok=JeUIjuxB)
![Sample of [paragraphs_item:field-grid-block-link:title]](https://webarchive.library.unt.edu/web/20170119052355im_/https://www.drought.gov/drought/sites/drought.gov.drought/files/styles/grid_thumbail/public/externals/ec5547c2e9ee2d097942994c4565fc72.png?itok=CoD0AX7g)
![Sample of [paragraphs_item:field-grid-block-link:title]](https://webarchive.library.unt.edu/web/20170119052355im_/https://www.drought.gov/drought/sites/drought.gov.drought/files/styles/grid_thumbail/public/externals/e8497ddc5c183ad7776065f09417fd8c.png?itok=1G1rDYj9)
![Sample of [paragraphs_item:field-grid-block-link:title]](https://webarchive.library.unt.edu/web/20170119052355im_/https://www.drought.gov/drought/sites/drought.gov.drought/files/styles/grid_thumbail/public/externals/72e9ebcadc0b791c35f5d47eb4ba8a81.png?itok=bSmpZhio)
![Sample of [paragraphs_item:field-grid-block-link:title]](https://webarchive.library.unt.edu/web/20170119052355im_/https://www.drought.gov/drought/sites/drought.gov.drought/files/styles/grid_thumbail/public/externals/10f9903bd60a8d29f09e50196bd8c41a.png?itok=W4GZiU2C)
The Standardized Precipitation Index (SPI) indicates how unusual the amount of accumulated precipitation is, compared to the historical record over a given time scale.
![Sample of [paragraphs_item:field-grid-block-link:title]](https://webarchive.library.unt.edu/web/20170119052355im_/https://www.drought.gov/drought/sites/drought.gov.drought/files/styles/grid_thumbail/public/externals/1aa665fdff0179db278c0f60f0c76d36.png?itok=_XH3J7sG)
![Sample of [paragraphs_item:field-grid-block-link:title]](https://webarchive.library.unt.edu/web/20170119052355im_/https://www.drought.gov/drought/sites/drought.gov.drought/files/styles/grid_thumbail/public/externals/7b919aaf2c3e6285697a0ef17c8a72ce.png?itok=V96O7yc-)
![Sample of [paragraphs_item:field-grid-block-link:title]](https://webarchive.library.unt.edu/web/20170119052355im_/https://www.drought.gov/drought/sites/drought.gov.drought/files/styles/grid_thumbail/public/externals/3fcbb3ab6204550c4581e959f90077c6.png?itok=_iH84vUa)
![Sample of [paragraphs_item:field-grid-block-link:title]](https://webarchive.library.unt.edu/web/20170119052355im_/https://www.drought.gov/drought/sites/drought.gov.drought/files/styles/grid_thumbail/public/externals/82b802b5f4650310b276c31224270c10.png?itok=7n9gKLww)
![Sample of [paragraphs_item:field-grid-block-link:title]](https://webarchive.library.unt.edu/web/20170119052355im_/https://www.drought.gov/drought/sites/drought.gov.drought/files/styles/grid_thumbail/public/externals/67d35c879dea6e39559e6c2beacd9744.png?itok=kAdJB0e6)