August 2015 - Monsoon Performance, continuing to be below normal!

The South West Monsoon in 2015 is turning out to be a deficient rainfall year in Goa, in line with the deficient rainfall witnessed in the rest of the country.

As against normal area weighted average rainfall for the State of Goa  of 682 mm in August, only 515 mm rainfall was recorded, which is 24% below normal. Overall in 2015 SWM season from June 1 till August 31, the rainfall was 22% below normal. This monthly deficiency trend is seen in every month this year.

With El Nino getting stronger and failure of the Arabian Sea branch of the SW Monsoon this year, Goa received just about 50% of the rains recorded in  the month of August 2014.

 During August 2015 there were just 2 days without rainfall, but only 8 days with above normal rainfall. The rainfall was substantially below normal rest of the days.

Places in the interiors of Goa, at the base of the western Ghats, like Valpoi, Sanguem, Sakhali etc have performed poorly in 2015, compared to earlier years, leading to the overall -22% overall rain deficiency this year.

Sanguem is the seasonal topper so far this year, being the only place in Goa to have received more than 100 inches of rainfall till August 31. It is closely followed by Valpoi, Ponda, Old Goa, Quepem and Sakhali.

The rainfall recorded at various centres in Goa month wise till August 31 is as per the chart below:

While the Selaulim Dam, with largest water holding capacity, located near Sanguem, was reported to be over flowing, other major water reservoirs including the Anjunem Dam in North Goa, were still below the maximum level.

The daily rainfall chart of Vagaries Goa at Aquem, Margao indicates the pattern of rain in August this year.

The overall monsoon performance for India indicates a deficiency of 11% till August 31, 2015.

The failure of the monsoons throughout the west coast and in the Gangetic Plains is very telling.

Outlook for the rest of the season ending September 30th is not very encouraging. There are indications that the withdrawal of the SW Monsoon may be very imminent, if it hasn't already started from Pakistan and NW India. Click on this link, to understand the withdrawal parameters, as explained in the blog Vagaries of the Weather.

For daily updates on the rainfall all over Goa visit http://weatheringoa.blogspot.in/p/swm-2015-goa-graphs-and-charts.html

Sanguem becomes the first rain Centre in Goa to cross 100 inch mark in 2015!

The rain activity witnessed in Goa on August 26 -27 has meant that Sanguem has become the first Rain Centre to cross the Century mark (in inches) this monsoon season in Goa.

During the 24 hours ending 0830 on August 27, Sanguem recorded heavy rainfall of 75.6 mm, taking the seasonal total to just over 100 inches at 2569.8 mm (101.2 inches).

The top three rain centres as on date are:

1. Sanguem: 101.2 inches

2. Valpoi: 95.6 inches

3. Ponda: 93 inches.

The Area Weighted Average Rainfall for Goa has reached 2042 mm ( 80.4 inches) against normal at this time of 2638.6 mm (103.9 inches), showing deficiency of -23%.

It is worth noting that last year till August 27, 2014, Goa had received total average rainfall of 2334 mm, which was -11% below normal. However due to excellent rains late in August and in September, last year SW Monsoon season had ended with surplus rainfall of +3%.

Such a scenario is far from cards this year, due to strengthening El Nino and the weak Arabian Sea Branch of the SW Monsoon so far.

The Rain Centre wise total rainfall recorded from June 1, 2015 till August 27, 2015 is as below:

Weekend of August 21, 22 and 23 August to see moderate rain activity in Goa - Posted August 21

Rain activity resumed after a gap of three days with heavy thunder storm affecting almost the whole of Goa after 2 am on Friday August 21.

source: http://www.imdgoa.gov.in

The rainfall recorded till 8.30 am on August 21 was heaviest in Margao and Dabolim rain centers of IMD.

The Rain Gauge of Vagaries Goa stationed at Aquem, Margao recorded 64 mm during the same period. The thunder storm activity was most intense between 2 am and 4 am, August 21 at Aquem, Margao. This brought the total rainfall at Vagaries Goa to 2045 mm.

The weather Blogger Rajesh Kapadia in his latest Blog post at the Vagaries of the Weather Blog, estimates moderate rainfall for Konkan and coastal Karnataka in the next three days. You can read his blog post by clicking on this link.

Sanguem with total seasonal rainfall so far of 96.4 inches, above Valpoi with 92.1 inches, looks set to cross the 100 inch mark before August end. However Pernem has so far received just 60.1 inches during the same period.

The area weighted average rainfall for Goa continues to be deficient, having received -22% below normal rainfall so far.

Goa needs above average rainfall on all days of the rest of the season, to recover to normal category, which seems a tall order right now!

Mid August 2015 - Deficient Monsoon rains continue in Goa

The IMD released cumulative rainfall map for India from June 1 to August 15, 2015, presents a stark picture of the failure of the Arabian Sea branch of SW Monsoons this year, badly affecting the quantum of rainfall received on the West Coast of India. The red areas in the map indicate departure from normal from -20 % to -59%.

Goa, on the west coast of India, is no exception, having so far received just 79% of the normal Monsoon rains, leaving a departure from normal of -21%.

Continuing the deficient trend seen in July 2015 as detailed in this post, the rains in the first 15 days of August were lower by -17%.

Against normal rainfall of 2434 mm during June 1 and August 15, Goa has received only 1934 mm area weighted average rainfall, leading to this -21% deficiency. In the year 2014 during the same period, the deficiency was -15%.

Interestingly, comparison between rainfall received till August 15th during 2014 and 2015 throws up some interesting facts:

It can be seen that Valpoi, Sanguem, Sankhali, Canacona, Pernem and Margao have contributed substantially to the reduced area weighted average rainfall for Goa during 2015, compared to 2014. While rainfall in Ponda, Old Goa, Mapusa, Panaji, Dabolim and Mormugao has marginally increased or remained almost same.

This year, while it has rained everyday in the first 15 days of August, there have been just 2 days with above normal rains.

As a result the departure from normal which was -21% at the end of July 2015, has remained at that level.

It is being discussed widely in the weather forums on the web, that the El Nino phenomenon is now developed and would leave its mark in the rest of the Monsoon season in India.

As things stand today and analysed in this post at the blog The Vagaries of the Weather, the scenario is not looking good.

What happens over the next 45 days, will determine if we will have a deficient Monsoon season (-20% to -59%) or a normal monsoon season (+19% to -19%) this year!

Vagaries estimate of rainfall over next fortnight - Posted August 9, 2015

The top waether blogger Rajesh Kapadia has posted his estimate of all India rainfall over the next fortnight till August 20, 2015 at his weathert blog The Vagaries of the Weather.

The same is reproduced below:

Goa has indeed being seeing medium to heavy rains over last two days in many areas. Vagaries anticipates this trend to continue over next few days.

Hopefully this will help to reduce the deficit of 21% Goa has reported till August 9, with area weighted average rainfall climbing slowly to 71 inches as against average of 90 inches :

 However whether its going to arrest the increasing red areas showing deficient rain regions in the all India map of IMD is to be seen:

Rainfall so far in Goa and the Western Ghats - A comparison. Posted August 9, 2015

Mr Rohit Aroskar, who has his own page at Vagaries of the Weather Blog has posted on google map, a comparison of the seasonal rainfall from June 1 to August 7, 2015 for areas in and around Goa. The same is reproduced here again:

One can clearly see from the map that the rainfall increases from the coastal belt to the top of the western Ghats.

While Sanguem and Valpoi at the base of the Ghats have received around 200 cms (2000 mm) during the period from June 1 to August 7, 2015, Ambolim,(Maharastra), Kanakumbi, Amgaon, Castle Rock and Kundal (all in Karnataka) have received more than 250 cms (2500 mm).

The straight line distance from Panjim to Amgaon is just 52 kms, but the variation in rainfall is significant indeed!

Thanks to Rohit Aroskar for this instructive graphic! You can follow his innovative graphics by clicking on this link.