December 2023 Global Soil Moisture 3-Month Trend and Forecast

Highlight: Southern hemisphere summer 2023-24 drought for Brazil and Western Australia.

Fig. 1: The November 2023 global soil moisture anomalies and 3-month trend.

Observation discussion: Reginal wetter changes (10) outnumbered the drier changes (7) during SEP/OCT/NOV 2023 (Fig. 1). Drought worsened in Brazil and Western Australia to Western Indonesia while dry zones steadily emerged over the East-central U.S. and Interior South Africa. Wetter zones were most profound in Northeast Africa to Saudi Arabia in response to the positive phase Indian ocean dipole (+IOD). The +IOD regime also contributed to wetter soil moisture conditions near and north of the Caspian Sea and Interior Southeast Asia. Late autumn open water north of Russia lead to advection precipitation most of which was snowfall to shift North Coast and Northeast Russia soil moisture conditions wetter Central Europe trend was much wetter while the Canadian Drought remains intact.

Fig. 2: November 2023 global soil moisture anomalies and 3-month forecast.

Forecast discussion: The 3-month outlook valid for DEC/JAN/FEB 2023-24 indicates strengthening drought across Eastern Canada reaching the Upper Midwest of the U.S., wetter conditions across California to the Great Basin and the Southeast U.S., and persistent dry conditions in Brazil while Southeast Brazil into Northeast Argentina continue wet (Fig. 2). Drought develops in South Africa and strengthens across western and northern portions of Australia plus the southern half of Indonesia. A wetter seasonal outlook is indicated for much of Eurasia including Southwest Russia, Iraq/Iran eastward to the China Coast, and across North-central Russia. Lingering +IOD influence continues to soak Northeast Africa.