Rain expected in January month

Rain expected in January month

 Sources from- Tami Nadu Weatherman
As per official announcement, he Powerhouse of NEM, Siberian High still remains strong and as a result of this the Western Pacific is active and which in turn keeps sending pulses (moisture push) into our Bay of Bengal.

Lets see the Chennai and Tamil Nadu rainfall in January, historically, we get very less rains in January. Here are the exceptional years which has defied the odds.
Tamil Nadu Historic Top January Rainfall since 1876 (min 75 mm)
  • 1923 – 169.3
  • 1921 – 162.3
  • 1920 – 150
  • 1943 – 135.1
  • 1909 – 122.4
  • 1934 – 91.9
  • 1963 – 90.9
  • 1985 – 89.9
  • 1990 – 82
  • 1961 – 81.5
  • 1954 – 79.8
Chennai City Historic Top January Rainfall since 1813 (min 100 mm)
  • 1915 – 244.1 (All time Record for January)
  • 1827 – 218.4
  • 1918 – 204.5
  • 1947 – 193.5
  • 1920 – 179.8
  • 1995 – 171.2
  • 1843 – 165.1
  • 1986 – 152.9
  • 1921 – 138.7
  • 1909 – 137.7
  • 1868 – 121.2
  • 1923 – 113.3
  • 1906 – 102.9
As you can see, the Last time Chennai got over 100 mm monthly rains in January was in 1995.
1st Spell – Just a Easterly Trough
The 1st spell will start around 20th Night / 21st early morning and the coastal areas from Delta Coast to Chennai will get widespread rains moslty. Some places in interior Tamil Nadu and south Tamil Nadu will get isolated rains. This spell is a small one and lasts only on 21 and 22nd January. Delta and north TN coast will get the most of this system. Light rains possible on 21-22 in Coimbatore / Nilgiris belt.
 
2nd Spell – Possible Low Pressure Area
Mostly the spell will start around 24th (+ or -1 day). This is nothing but a West Pacific Depression moving into our Bay of Bengal (Refer pic). This will be the one to watch out as it will give widespread rains to entire Tamil Nadu. More on this spell later as we near the event to get more clear picture.
Rise in night Temperature from 20th January
As we move into 20-21st we can see increase in night temperature due to the clouds and heat gets trapped in them rather than escaping the atmosphere. Ooty which has recorded 1.8 and 2.8 C in the last 2 days will see increase in night temperature after 2. The all-time freezing record for Ooty is -2.7 C recorded during January 1976.
Will January 2017 rains be added to above exclusive list of years
As you can see odds are against Chennai and Tamil Nadu. Chennai January rainfall average is just around 20 mm. So expecting over 100 mm rainfall in January for Chennai is like expecting 5 times its normal average. I feel there is good possibility that this January rains in Chennai will get near these historic year figure of at least 100 mm (overall for month) or at least come close to it. For Tamil Nadu as a whole it would be a miracle to get into this list of 75 mm and above. But as you can see both GFS and ECMWF are expecting widespread rains. Anything like 30-40 mm till month end is a bonus for us. So, lets welcome it open hands. There is no fear of floods nor a Cyclone this time. Even if it doesn`t generate inflow into lakes, the ground water will at least get some re-charge.