This is a Preprint and has not been peer reviewed. This is version 1 of this Preprint.
ECMWF SEAS5 Seasonal Precipitation Outlook and Preliminary Rainfall-Based Flood Screening for Iraq: October 2026–January 2027
Downloads
Authors
Shaheen Mohammed Saleh Ahmed 
Abstract
This preprint provides a hydrological and hydrogeological interpretation of ECMWF SEAS5 monthly precipitation forecasts for Iraq from October 2026 through January 2027. The analysis uses the ECMWF System 51 ensemble mean initialized on 1 August 2026. The downloaded time-mean total precipitation rate was converted from metres per second to monthly precipitation depth in millimetres using the actual number of days in each valid month. The original 1° × 1° analytical grid was retained without spatial smoothing and clipped to the supplied national boundary of Iraq. Derived products include four-month precipitation accumulation, peak monthly rainfall, rainfall concentration, temporal variability, maximum month-to-month increase, a transparent precipitation-only screening index, relative screening classes, and three-dimensional visualizations. The forecast exhibits a strong north–northeast precipitation gradient. Representative four-month totals are 574.24 mm near Erbil, 483.87 mm near Sulaymaniyah, 348.92 mm near Kirkuk, and 294.13 mm near Duhok, compared with 140.34 mm near Baghdad and 113.31 mm near Basra. The strongest seasonal hydrological signal therefore occurs across northern and northeastern Iraq. Hydrogeologically, enhanced winter precipitation may increase diffuse and focused recharge in permeable alluvial, fractured, and karstic aquifers, but monthly rainfall alone cannot quantify recharge. Likewise, the rainfall-screening maps are preliminary regional prioritization products rather than physical flood-hazard or inundation maps because they do not include topography, drainage, soil, land cover, antecedent moisture, rainfall intensity, river capacity, or observed flood inventories. The products should therefore be used as a seasonal hydroclimatic outlook and as a first-stage prioritization layer for subsequent high-resolution hydrological, hydraulic, and hydrogeological modelling.
DOI
https://doi.org/10.31223/X52213
Subjects
Earth Sciences, Environmental Sciences, Oceanography and Atmospheric Sciences and Meteorology, Risk Analysis
Keywords
ECMWF SEAS5; Iraq; seasonal precipitation; preliminary rainfall-based flood screening; groundwater recharge; hydrogeology; GIS; ensemble forecast
Dates
Published: 2026-08-12 06:39
Last Updated: 2026-08-12 06:39
License
CC BY Attribution 4.0 International
Additional Metadata
Conflict of interest statement:
The author declares that there are no known financial or personal conflicts of interest that could have influenced the work reported in this manuscript.
Data Availability:
The ECMWF seasonal forecast source data are publicly available from the Copernicus Climate Data Store dataset “Seasonal forecast monthly statistics on single levels.” This study used ECMWF System 51 ensemble-mean total precipitation initialized on 1 August 2026. The analysis code, processed tables, and derived figures were produced for this study. A permanent repository DOI should be added to this paragraph and to the EarthArXiv metadata once the accompanying research package is deposited. The Iraq administrative boundary should be redistributed only in accordance with its original licence.
Metrics
Views: 27
Downloads: 6
There are no comments or no comments have been made public for this article.