Rainfall declines by over 40 compared to longterm average
Rainfall declines by over 40% compared to long-term average
TEHRAN –Since the beginning of the current water year (September 23, 2024), precipitations have dropped by 42 percent compared to long-term average, according to Metrological Organization.
The accumulated rainfall in the current water year has amounted to 38.4 mm which indicates a 42-percent decrease in comparison to the long-term average rainfall of 66.4 mm, ISNA reported.
The average precipitations from December 24 to 30 totaled 4.2 mm, showing about 17.3 percent decrease compared to 5 mm in the long term.
From the beginning of the winter, average rainfall equaled 4.5 mm. Compared to 7.3 mm rainfall recorded in the long term, it has dropped by 38.8 percent.
Apart from Mazandaran and Kordestan provinces, the amount of precipitation in other provinces has been less than normal.
Hormozgan province recording 6.3 mm of rainfall has experienced an 85.6 percent decline in precipitations, compared to 42.2 mm recorded in average long-term.
Rainfall in Tehran has also lowered. From September 23 to December 30, 2024, the average precipitation came to 53.8 mm, decreasing by 32.4 mm compared to 79.5 mm rain recorded in the long term.
Below-average rainfall forecasted for next six weeks
According to Metrological Organization, average precipitation is projected to be less than normal from December 30 to February 18.
In the first week (from December 30 to January 5), the precipitation in the eastern and the central part of the country, as well as the eastern slope of central Zagros, and parts of Gilan province will be above normal, while it is predicted to be less than normal in other areas, ISNA reported.
Accumulated precipitations will be 20 to 50 mm in the central and eastern parts of the country.
The average air temperature is predicted to be normal over the Caspian coast, the northwest, and the southern part of the country, and 1-5 °C less than normal in other areas.
The temperature in central areas of the country is likely to exceed 3 – 5 °C.
In the second week (January 6-17), the amount of rainfall will be less than normal, and in most parts of the country, no rainfall is expected.
The east, southeast, and some central parts of the country will experience normal temperatures. In the rest areas, it will get 1-5 °C above normal.
The northwest and east of the southern Zagros mountains will experience the maximum increase (3-5°C) in temperature.
During the third and fourth weeks (January 18 – February 4), precipitation is expected to be less than normal in the south and east of the country, more than normal in the north, and normal in other regions.
The cumulative rainfall in the fourth week is estimated to be between 50-100 mm in parts of Zagros and central Alborz.
The highest air temperature will occur in the third week, getting 1 to 6 °C above normal.
In the southeast, south, and the provinces located in the middle and south Zagros and on the Caspian coast, it will get 1-3 °C and in other areas 3-6 °C above normal.
The air temperature will be 1-3 °C above normal in the fourth week.
Precipitation in the fifth week (February 5-11) is said to be normal in the northwest, northern Zagros, Alborz mountains, northeast, and some parts of the southeast, and less than normal in other areas.
The air temperature is estimated to be 1 °C above normal in the east and north of the country, and 1-3 °C above normal in other regions.
The rainfall in the sixth week (February 12-18) in the eastern parts, parts of the south and southwest of the country is forecast to be less than normal and in other areas, it is estimated to be normal.
It is expected that the air temperature in the sixth week in the central, and southern Zagros, as well as the south of the country, will get 1-3 °C above normal. It will be normal in other regions.
Over 250mm rain in previous water year
The previous water year (September 22, 2023 – September 22, 2024) came to an end with receiving 252.7 mm of precipitation, showing a 19 percent increase compared to the year before.
The low precipitations at the beginning of the previous water year were worrisome, but the volume of precipitations improved with the passage of time.
Due to successive years of drought, the increase in rainfall amounts did not compensate water deficit in the country, some provinces are suffering from water shortage, IRNA reported.
A total of 10 provinces received less than normal rainfall.
According to the latest reports, the total amount of recorded rainfall in the previous water year (ended on September 23) amounted to 252.7 mm, which signifies a 19 percent increase compared to 212.9 mm rain received in the water year before (September 2022 –September 2023).
Compared to the long-term figure, 248.7 mm, it shows a two percent increase.
MT/MG
source: tehrantimes.com