Drought Forecasts
The science of drought forecasting is still in its infancy. However, better models and understanding of the dynamics between the oceans, land, and atmosphere, along with increased computing power, have made forecasting more feasible. For example, the U.S. Seasonal Drought Outlook describes areas of the country where drought is expected to improve, persist, or worsen during the next three months. However, this is a broad representation of drought conditions across the country. For local areas, we often need to examine a combination of drought indicators, such as weather conditions, surface water, soil moisture, and climate change. These all have the potential to affect drought occurrence. Some of these components are introduced below.
The Seasonal Drought Outlook is issued bi-weekly by NOAA’s Climate Prediction Center.
It is the only official drought forecast issued by NOAA.
The term “seasonal” means that the forecast is issued for a 3-month window. The forecast shows whether drought conditions, as depicted on the US Drought Monitor, are expected to persist, improve, or develop in new areas.
U.S. Seasonal Drought Outlook. National Weather Service.
CPC’s Palmer Drought Severity Index Forecast
The Palmer Drought Severity Index (PDSI) is a good indicator to predict drought conditions in a probability framework.
The probability is obtained by running the current Palmer drought data for climate divisions 4 months ahead using the weather scenarios (temperature and precipitation) of all the past years since and including 1931.
CPC’s Drought Termination Product
Knowing the amount of precipitation needed to end a drought is also useful. This tool displays the probability of rain occurring
based on likely forecast scenarios. For details, click here.