This has been one of the wettest Septembers for Karachi, probably surpassing the year 2011. Around 200+ mm rain was recorded during the four-day rains in early September in the city (when taken the highest 24 hour stats across city’s stations) while the 2nd spell in September has caused 70+ mm rain so far. Now eyes should be on a third spell!
There are chances of ‘Lu’ Winds (strong warm winds) in Karachi due to the expected formation of a depression in the Bay of Bengal which is very likely to move towards central India after that its track is disputed. This will be 2021’s most strongest monsoon system. Since wind flows of strong weather systems are larger hence they impact the prevailing wind patterns in the area, therefore;
- In the coming week, Karachi’s temperature will range from 35°C to 36°, peaking at 37°C to 39°C during the mid of the week (+1°C error).
We have been keeping an eye on the probability of this system since Sept 1 and are currently maintaining its chance at 40% for south Pakistan. This will be a significant weather system to watch. If it comes to South Pakistan, there can be widespread very heavy to extremely heavy rains in many areas of Sindh. Since the conditions are unfavorable due to -IOD, dry winds and SST, there is a huge variation between GFS, ICON and ECMWF. Such unstable runs by numerical model makes it difficult to determine the exact situation. It is expected by September 14 to have some clarity. But for now, its confirmed that a depression is developing in the Bay of Bengal.
Update – September 26
70 mm rainfall was recorded due to this system. The depression has stalled over central India due to westerlies but after much delay its remnants were able to cause thunderstorms in Karachi.