On the 17th. March, I observe the first 40 c has been recorded at Akola (Vidarbh), and again at Baroda on the 18th., Exactly as anticipated in the last blog. But, today (18th.), the heat has spread more than expected all over north and central India, with most places recording temperatures 7 c above normal. New Delhi and Hissar at 38c were 7c above and many places were 6c above normal. In IMD terms, temperatures above 6c more than normal amounts to a "heat wave". The maximum temperature map of 18th. shows the temperatures of 37/38c spreading from Rajasthan through central India eastwards.
Down south, and "upper air circulation" has formed over the south east Arabian Sea. This may descend and form a low pressure in the same region, as the easterly flow is strong enough to pump in sufficient moisture (IMD map below).
Most international models forecast rain in extreme south to continue till the 20th., and the rain belt gradually moving north towards Maharashtra through Karnatak 19th. onwards.
Models predict rain (should be light) in Mumbai by Sunday night/Monday.
If the moisture surge is strong enough to push the rain further north into central India from Mahrashtra, it should cool the northern/central regions by next week, and wipe out the heat wave.