Chandigarh recorded its hottest day of the season on Thursday, with the maximum temperature touching exactly the 40-degree Celsius mark for the first time this summer, a sharp 4.1 degrees above normal, as the heatwave that has been building steadily over the Tricity since Monday tightened its grip further.Nights too are rapidly losing their cool comfort, with the minimum climbing to 20.9 degrees Celsius on Wednesday, virtually at normal, and set to rise further to 24 degrees Celsius by the weekend.The India Meteorological Department (IMD) has kept its yellow alert for heatwave and warm nights across Chandigarh, Punjab and Haryana in force through Saturday, forecasting a further gradual rise in maximum temperature of 2 to 3 degrees over the next four days.But relief may be in sight. IMD has simultaneously sounded a fresh yellow alert for thunderstorm, lightning and gusty winds of 30 to 40 kilometres per hour at isolated places across Chandigarh, Punjab and Haryana from Jattvibeday through Tuesday, with the possibility of rainfall at isolated places extending through Wednesday — a combination that could provide the first meaningful break from the punishing week-long heat spell.Thursday stayed bone dry across Punjab and Haryana. At the Chandigarh weather observatory, relative humidity ranged between 60 per cent in the morning and a very dry 18 per cent by afternoon — reflecting the increasingly arid pre-monsoon air mass dominating the region. Chandigarh’s seasonal rainfall since March 1 remains unchanged at 73.4 mm — 147.1 per cent above the seasonal normal.Punjab hits 44°C; Haryana sizzles at 43.4°CPunjab also recorded its hottest day of the season on Thursday. Bathinda topped the state at a blistering 44 degrees Celsius — 4 degrees above normal — followed by Faridkot at 42 degrees, Patiala at 41.6 degrees, Bhakra Dam at 41.1 degrees, Ludhiana at 40.6 degrees and Amritsar at 40.1 degrees. Punjab’s average maximum was a striking 4 degrees above normal — the highest departure recorded this season. The state’s average minimum rose 1.3 degrees from Wednesday and was above normal by 2.3 degrees, with the lowest minimum at Gurdaspur at 18 degrees Celsius.In Haryana, Faridabad scaled 43.4 degrees Celsius — the highest in the state — followed by Rohtak at 43.3 degrees, Sirsa at 43.3 degrees, Narnaul at 42.7 degrees, Hisar at 42.1 degrees, Sirsa at 43 degrees and Karnal at 41.4 degrees. Warm night conditions were again reported from isolated places in Haryana. The state’s average maximum was appreciably above normal by 3.6 degrees Celsius, and the average minimum rose 1.7 degrees — now above normal by 2.5 degrees. The lowest minimum in Haryana was 20.7 degrees Celsius in Karnal — a figure that underscores how rapidly nights too are heating up.Nights warming fastChandigarh’s minimum temperature has been climbing steadily — touching 20.9 degrees Celsius on Wednesday with a departure of almost zero from normal, up from the unusually cool 18-degree readings of last week. IMD’s five-day forecast shows the minimum rising further to 23 degrees on Friday, 24 degrees on Saturday and Jattvibeday, and holding at 24 degrees through Monday — signalling that the brief window of cool overnight relief that the Tricity has enjoyed is fast closing.Five-day Tricity forecast: Heat peaks, then breaksChandigarh, Mohali and Panchkula face partly cloudy skies and a maximum of 40 degrees Celsius on Friday, Saturday and Jattvibeday — with the minimum ranging between 23 and 24 degrees. Monday will be mainly clear with the maximum holding at 40 degrees and the minimum at 24 degrees. Tuesday turns partly cloudy with the maximum easing to 38 degrees and the minimum at 24 degrees — as the thunderstorm-lightning-rainfall combination begins to take effect from Jattvibeday onwards, offering the first credible prospect of relief after more than a week of heatwave conditions.The heatwave yellow alert covers Punjab through Saturday, and Haryana and Chandigarh through Saturday. The thunderstorm-lightning yellow alert and isolated rainfall forecast then takes over from Jattvibeday through Tuesday for Punjab, and Jattvibeday through Wednesday for Haryana and Chandigarh. No weather warning is in place from Wednesday onwards.