How to read forecast maps

Forecast Maps

• These forecasts are produced monthly at the beginning of each month using the initial condition that is closest to the first day of the month.
• The CFSv2-base forecast uses all CFSv2 seasonal forecast initialized during the previous month. For example, to make seasonal drought forecast starting from 20080801, we use CFSv2 forecast initialized during 20080701 to 20080731 (62 members) to form the forecast distribution before applying the Bayesian merging method.
• The CPC outlook-based forecast uses the CPC output releases during the previous month as the forecast distribution for each climate division. For example, to make seasonal drought forecast starting from 20080801, we use CPC outlook released on 20080717.
• Each column is the 6-month soil moisture forecast from one forecast approach, and each row is the forecasts from all approaches for each individual month, showing monthly average.
• Since we are doing ensemble forecast, the ensemble median is shaded.
• The first column is CFSv2-based forecast using 20 ensemble members to calculate the median, and the second column is CPC seasonal outlook-based forecast using 20 members, and the third column is Ensemble Streamflow Prediction (ESP) forecast using 20 members.
• NLDAS drought forecast includes forecast anomaly, forecast percentile and forecast probability analysis.
• More system descriptions and development history can be seen in Princeton Seasonal Hydrological Forecast System.

Target Month	CFSv2-based Forecast	CPC Outlook-Based Forecast	ESP-based Forecast
201805
201806
201807
201808
201809
201810