A deep trough of low pressure will pull moisture northward from the Arabian Sea bringing widespread rain across the desert from around the Persian Gulf into Pakistan and Afghanistan during the beginning of the week. Cold air moving in from the north will lead to heavy snow across the mountainous terrain.
On Monday, the week will begin with rain from the United Arab Emirates into southern Iran. With moisture being pulled north from the Arabian Sea, some of the rain will be heavy in southeastern Iran with 13-25 mm (0.50-1.00 inch) possible. This will lead to typically dry waterways to rapidly swell with fast moving water. Rainfall will likely be lighter in Dubai as showers move in from the Gulf.
Most of these areas will dry out on Tuesday as the majority of the moisture slides to the east into southern Pakistan.
Snow across southern Iran on Monday can be heavy above 2000 meters (6600 feet) with as much as 30 cm (12 inches) likely to accumulate. Snow flakes could be seen as low as 1000 meters (3300 feet) on Monday night before precipitation ends, but there should be no accumulations in elevations this low.
While snow will be heavy in Iran, the mountains across Afghanistan will likely see even more snow from Monday into Tuesday due to a more prolonged period of precipitation.
Snow levels are expected to be 1500-2500 meters (5000-8200 feet) in Afghanistan. Many remote village in the mountains sit above these elevations and could see 30-60 cm (12-24 inches) of snow. This could block routes to some remote areas for days.
Kabul, Afghanistan lies just below 2000 meters (3300 feet) in elevation and will escape the majority of the snow, but the city will likely see snow mixing with the rain. Hills around the city will see some accumulation, though significant travel impacts are not expected.
The disturbance bringing this rain and snow will track to the northeast into the middle of the week bringing rain to northern Pakistan and northwestern India through as least Thursday. Heavy snow will shift east from Afghanistan into the western Himalayans. This system could eventually bring improvements to the poor air quality that has been plaguing the region for weeks.