During the 2019 growing season, Dr. Eric Hunt of Atmospheric and Environmental Research, Inc. will be providing weekly updates of the soil moisture index (SMI) from the Noah-MP land surface model in the NASA LIS framework for the eastern 3/4 of the U.S. where row-crop agriculture is more common. The Evaporative Stress Index (ESI) will also be included in our analysis once data for all of the U.S. are available later this month. The analysis is intended to provide the larger agricultural and meteorological communities insight as to areas where soil moisture is excessive or deficient compared to average for that location and what that may mean for impacts. It is my goal that these maps can be an early warning signal for flash drought development or where flash flooding could be likely in the coming week if heavy precipitation materializes. Please be advised that the SMI should be viewed as complementary, not a substitute, to the U.S. Drought Monitor (USDM) and that declarations of drought for a particular location should never be based on the SMI alone.
This blog post was partially supported by NASA grant NNH16CT05C.
Figure 1. The Soil Moisture Index (SMI) for the 7-day period ending 13 April 2019. Results are based on output from the 0-1 m (surface to 3.23 feet) layers in the Noah-Multiparameterization (Noah-MP) land surface model. Noah-MP is run in the NASA Land Information System (LIS) framework with the North American Land Data Assimilation Version 2 (NLDAS-2) forcing dataset. The SMI calculation is based on the soil moisture index created in Hunt et al. (2009) such that ‘5’(dark green) is the wettest and ‘-5’ (dark red) the driest for the period of record. The period of record used calculate the SMI for the current map is 1979-present.
Figure 2. Comparison of this week’s SMI map with last week’s SMI map.
Narrative:
The SMI indicates that the Corn Belt remains moist for this time of year, with the exception of lower Michigan. Slightly drier conditions were depicted over southeastern Illinois and southern Indiana as well.
Moving further west and south, the SMI was slightly negative across most of Missouri and into eastern Oklahoma and Texas. Significant precipitation is expected over much of this area, so I expect there to be less orange and red on the map at this time next week over that area.
Most of the southeastern U.S. saw significant improvement after storms late last week, with the most significant change occurring in northern Mississippi and Alabama. The latest U.S. Drought Monitor shows abnormal dryness and moderate drought occurring along the Gulf Coast and into South Carolina, in good agreement with this map. Additional improvement in soil moisture is likely with the forecast in that area.
Further north, the SMI is still indicative of somewhat drier than average conditions, but improvement was noted in much of the northeast. Drier conditions (i.e., negative SMI’s) persisted in much of the Appalachian region.
Please direct any feedback or questions my way ( Eric.Hunt@aer.com ).