Single-line diagram of the basins represented

Analysis of the Single-Line Diagram of the Shown Basins

The analysis of the unifilar diagram shows the distribution and classification of river basins according to the categorization of precipitation anomalies for the period between June 30 to July 29, 2026. In the Andean headwaters of the Marañon, Napo, Ucayali, and Amazon (PE) rivers, intense negative precipitation anomalies were concentrated in the Napo River basin, which was classified as “tending toward very dry,” the main stem of the Amazon River in Peruvian territory, and the Ucayali River basin, which was classified as “tending toward dry.” The Marañon River basin remained in normal conditions. The main course of the Solimões River and the basins of the Içá, Japurá, and Juruá rivers experienced rainfall below the climatological average, while the basins of the Coari, Javari, and Tefé rivers had rainfall slightly above the climatological average for the period; the basins of the Jutaí and Purus rivers, meanwhile, had rainfall close to the climatological average for the period. The Aripuanã and Mamoré river basins, which were in rainy conditions, and the Guaporé and Madeira river basins, which were trending toward rainy conditions, showed positive precipitation anomalies; the Beni and Ji-Paraná river basins recorded rainfall close to the climatological average. The Negro and Branco river basins recorded an intensification of negative precipitation anomalies compared to the previous period, and were categorized as very dry and tending toward extremely dry, respectively. On the left bank of the Amazon River within Brazilian territory, negative precipitation anomalies continued to predominate: basins in northeastern Amazonas were classified as tending toward very dry, while those located in the northeast and northwest of the state of Pará were classified as very dry. On the right bank, the Iriri, Juruena, Tapajós, Teles Pires, and Xingu river basins recorded positive precipitation anomalies; although significant for vegetation, the average 30-day accumulated precipitation ranged from 10 to 48 mm in these basins. On the other hand, the Abacaxis River basin was classified as tending toward dry conditions, with accumulated precipitation of 34 mm, indicating a shortage of rainfall in this region. The main course of the Amazon River within Brazilian territory experienced rainfall slightly below the climatological average.