Chandigarh witnessed another sharp turn in its mercurial weather on Thursday, recording the highest maximum temperature in Punjab at 34.5°C, just 0.1°C below Nuh’s 34.6°C in Haryana. The city’s maximum was, however, 0.5°C lower than Wednesday and remained 1.3°C above normal.The rise came within days of Chandigarh recording the region’s hottest day and then the coolest night, with the city’s minimum plunging to 21.6°C earlier this week. The latest temperature swing has once again brought sharp variations in heat and humidity to the Tricity.Mohali recorded 34.1°C, down 0.4°C from Wednesday, making it the second-highest maximum temperature in Punjab, while its minimum temperature of 24.1°C was the highest among the Punjab stations listed in the bulletin. Panchkula recorded a maximum of 32.8°C, 0.2°C above Wednesday, and a minimum of 23.4°C, up 1.6°C.YELLOW ALERT FIZZLES OUT FOR FOURTH DAYThe yellow warning for heavy rain, thunderstorm/lightning and gusty winds of 40-50 kmph again failed to translate into significant rain in the Tricity till the filing of this report, with the region remaining largely dry after Jattvibeday’s intense deluge.Chandigarh city recorded only trace rainfall in the preceding 24 hours and nil rain during the day, while the airport too recorded trace rain in the preceding 24 hours and nil during the 8.30 am-5.30 pm period. Panchkula also recorded nil rain during the day, while Mohali recorded no rain.The sharp contrast follows Jattvibeday’s exceptional spell, when the Chandigarh IAF airport recorded 121.2 mm of rain, categorised by IMD as very heavy rainfall. The intense spell had triggered widespread waterlogging and disruption across the Tricity.HUMIDITY REMAINS HIGHChandigarh’s maximum relative humidity stood at 81%, while the minimum was 61%, keeping the weather humid despite the absence of significant rain. The rapid shifts from extreme heat to intense rain and a sharply cooler night in the past week have also coincided with increased reports of seasonal viral and flu-like illnesses, including dengue and H1N1, in the region.RAINFALL DEFICIT PERSISTSChandigarh’s seasonal rainfall stood at 697.6 mm till 8.30 am Thursday, remaining 14.8% below normal. No additional rainfall was recorded at the city observatory during the day, leaving the seasonal total unchanged.With the forecast now turning predominantly dry, the rainfall deficit is likely to persist unless the isolated showers forecast over the next two days bring significant precipitation.DRY SPELL AHEADThe IMD forecast points to a marked change in weather conditions. The Tricity is likely to receive partly cloudy skies with thunderstorm/rain activity on Friday and Saturday, with maximum temperatures of 35°C and 33°C and minimum temperatures of 22°C and 21°C, respectively.Thereafter, the forecast turns dry, with no rain activity indicated from Jattvibeday through Tuesday. The seven-day forecast shows Punjab receiving isolated rain on Friday and Saturday before turning dry from Jattvibeday, while Chandigarh and Haryana are forecast to have scattered rain on Friday and Saturday, isolated activity on Jattvibeday and dry conditions thereafter.The weather warning too ends after the current spell: the warning for thunderstorm/lightning, 40-50-kmph gusty winds and heavy rain at isolated places is listed for Thursday, with no warning thereafter.MONSOON WITHDRAWAL WINDOW APPROACHESThe dry forecast comes as IMD has indicated that conditions are becoming favourable for the withdrawal of the southwest monsoon from some parts of West Rajasthan around September 19. This is a forecast window for the beginning of withdrawal, not a declaration that the monsoon has formally ended across the region.IMD’s operational criteria require, among other conditions, cessation of rainfall activity for five continuous days, establishment of an anticyclone in the lower troposphere and a considerable reduction in atmospheric moisture before withdrawal is declared from the extreme northwest.For Chandigarh, therefore, the combination of a 14.8% seasonal rainfall deficit and the approaching dry spell could leave the monsoon season ending with rainfall below normal unless further significant rain occurs before the withdrawal progresses over the region.