Vanakkam! International weather models see mostly cloudy skies for Chennai today (Sunday), followed by increasing clouds into the evening with showers developing into the night with chance of rain overall assessed at 30-60 per cent. Winds will  be variably north-easterlies, with the temperature peaking to 29 degree Celsius. Cloudy with showers is the forecast for the morning after (Monday).

The Chennai International Airport (MAA/VOMM) reported foggy conditions with temperature at 26 degree Celsius and  an average delay in arrivals (nil to start with earlier in the morning) of five minutes and in departures of nine minutes. No rain/showers are forecast for Puducherry and the other major cities in Tamil Nadu including Salem, Coimbatore, Tiruchirappalli, Madurai and Thoothukudi even as cloudy to mostly cloudy conditions may prevail. 

Sudden downpours in Tamil Nadu

Meanwhile, the convergence of northerly winds fanning down the Arabian Sea and easterlies in and around Sri Lanka and parts of Tamil Nadu and extreme South Peninsula led to sudden downpours at many places overnight. After a productive  Saturday, rain showers drenched areas in and around Chennai, Ramapuram, Kelambakkam, Siruseri, Guduvanchery, Perungalathur, Maraimalai Nagar (very heavy), Kelambakkam, Chengalpattu, Maduranthakam (heavy), Uthiramerur, Thennangur, Vandavasi, Thellar, Viranamur (heavy), Kattupakkam (heavy), Kattupakkam (heavy), Ambattur and Thirumazhisai this (Sunday) morning. The Regional Meteorological Centre, Chennai, under the India Meteorological Department (IMD), has predicted light to moderate rain for Tamil Nadu and Puducherry to continue into the next week as well. This is supported by international model outlooks.

The Japanese Meteorological Agency hints at the rainfall regime heading in a U format over the South Peninsula (covering the coasts on either side and land over extreme South represented by southern Kerala and Tamil Nadu) and progressively into a V that confines rains to the Peninsular Tip of India (Kanyakumari and South Kerala) and northern half of and Central Sri Lanka during this period. 

Outlook for December-January-February

So light showers are forecast for the Peninsular Tip and the northern half and Central Sri Lanka during the week from December 22 to 29. Rainfall anomaly forecast for the month of December as a whole is slightly above normal in a U over the South Peninsula in India and most of Sri Lanka. An extended rain forecast for the South Asia region put out by the Regional Climate Centre of IMD, Pune, also favours slightly above normal rainfall for the South Peninsula right into December 26, before gradually reducing.

This is more or less supported by the probabilistic multi model ensemble forecast using dynamical models from the 11 Global Producing Centres (GPC) of the World Meteorological Organisation (WMO) for the December-January-February season. Accordingly, there are equal chances of receiving below normal, around normal or above normal rainfall over the region during this three-month season. Interestingly, out of 11 GPC individual models, at least two have predicted above normal rainfall and three have predicted below normal rainfall during the season, while there is no signal from the six remaining GPC models. The Centre for Weather Forecasts and Climate Studies and National Institute of Space Research is the one model that has forecast above normal rainfall for most of the South Peninsula excluding northern and coastal Tamil Nadu for the season.

bird

An early bird gets started with its morning chores as Chennai wakes up to a cloudy day. Cloudy with showers is the forecast for the city till Monday morning.

 

Western disturbance triggers heavy rain

Meanwhile, a western disturbance and an offspring-induced cyclonic circulation continued to play havoc with weather in winter-hit North and North-West India, with widespread rainfall or snow being reported for a third day yesterday (Saturday) across Jammu & Kashmir, Himachal Pradesh and Uttarakhand, just as the IMD had predicted. Hail was reported at isolated places over Uttarakhand. The chief amount of rainfall received during the day (in cm) were: Manali-10; Moradabad, Pahalgam and Dharamsala -9 each; Devprayag and Shimla-8 each; Quazigund and Nangal-7 each; and Batote and Chamba-6 each. The western disturbance was located this (Sunday) morning along a latitude covering Srinagar, Pulwama and Reasi and was moving further away to the North-East to exit the country, though its underbelly will continue to graze the eastern parts of the country (East Uttar Pradesh, Bihar and the North-East). 

Dense fog, cold wave to follow 

The offspring cyclonic circulation was still parked over Punjab and will  now set up dense fog conditions thanks to the colder Arctic air that trails the disturbance and the lingering moisture it has left behind before giving into a likely cold wave. As if on cue, the IMD said   the weakening of the western disturbance will  significantly reduce precipitation over North-West India but isolated to scattered rain snow may lash the hills of the region. Minimum (night) temperatures will drop significantly (by 2- to 4 degree Celsius) over North-West and Central India over  the next two or  three days. Cold wave conditions may set in over Jammu & Kashmir, Himachal Pradesh and Uttarakhand during this period. Due to favourable meteorological conditions, dense fog at a few places with very dense fog at isolated pockets may envelop Punjab, Haryana, Chandigarh, Delhi, North Rajasthan and Uttar Pradesh in the morning hours. Dense fog at isolated places is also likely over North Madhya Pradesh and Bihar. Respite will  be at hand likely from Wednesday, when a fresh western moisture with upfront moisture carry (providing warmth and bringing back the clouds) arrives from across the border, though day temperatures might dip in the bargain. It may not be as intense the previous disturbance, but might   suddenly intensify   over Afghanistan and Pakistan ahead of reaching North-West India. 

Meanwhile,  Chennai weather bloggers tweeted their hearts out over the prospects of extended showers for the city and other parts of Tamil Nadu. There was concern particularly about  the rain  playing spoilsport with the India-West Indies  ODI on Sunday.

Meanwhile, the euphoria over the showers continues.

 

comment COMMENT NOW