August 2014 Rainfall Analysis - Ending with a Big Bang!

Heavy to very heavy record downpour in the last 6 days of August was the highlight of the rains in August 2014 in Goa. The rains wiped out the rainfall deficiency, yielded 50 to more than 60% of the total rains for the month and created flooding in low lying areas of many towns and villages of Goa.

The deficiency which was -49% in June '14 and -17% in July '14 turned positive to +1% with Area weighted total rains from June 1 to Aug 31, 2014 measuring 2721.4 mm ( 107.14 inches) against a normal of 2691.5 mm (105.96 inches).

Seasonal rainfall at Panjim, which IMD had been giving out as Goa's rainfall, before the present system of Area weighted average started also showed a similar trend:

South Goa recorded more rainfall than North Goa in August 2014, with Sanguem receiving the highest rainfall.

In fact Goa as a whole received more rainfall in August 2014 than in August 2013, as seen the comparison for top five wet places in Goa (Rainfall figures in inches):

At the end of August 2014, Valpoi continues to remain the wettest, but for how long into September before Sanguem overtakes it will be interesting to watch! The ranking as on August 31, 2014 is as below:

 

 

Comparative figures for top 5 stations over last year are as below:

 

 

 

However this excellent performance in August was characterized by a 13 days monsoon break like period from August 12 to August 24, with extended sunshine and day's high climbing to 32-33 C, +4C above normal! This is brought out clearly in the daily rain chart for Margao:

 

 

 

But the intensely heavy rainfall which started on August 26 and continued till August 31 contributed to 50 to 60% of the month's total rainfall in just 6 days:

 

In fact Panjim received a record rainfall of 228.7 mm (9 inches) in 24 hr period ending 0830 hrs on August 30, just missing by a whisker the record for highest one day rainfall in August set on August 1, 1981 with 242 mm. However it was the highest in a decade and wreaked havoc in low lying areas of Panjim and Taleigao with flooding, mud slides and house collapses. Fortunately no loss of life was reported.

 

So we enter September on a happy note as the rainfall deficiency has been wiped out. Let's see what September has in store!

A Wet Ganesh Chaturthi 2014 - Updated August 28, 2014

Monsoon has become vigorous over Goa since last three days and will continue to remain very active with very heavy to heavy downpour over the next three days coinciding with the popular Festival of Ganesh Chaturthi from August 29 to August 30th!

A low has formed in the Bay of Bengal off the coast of North AP / Odisha around 17N and under its influence the monsoon trough has become active in the Arabian Sea off the West Coast. This low is expected to track westward over land as a strong UAC, bringing rain to most parts of India.

The IGES/COLA forecast for the next fifteen days indicates very heavy rains on the west coast till 5th September and reducing thereafter as indicated below:

The Daily rain chart for Margao Goa reflects the increase in rain since August 25th:

The weekly analysis by IMD Goa, for week ending August 27, 2014 clearly indicates the above normal rains this week, particularly in South Goa.

Over the Ganesh Chaturthi Festival Days of August 29 and 30, the days are expected to remain heavily overcast and most parts of Goa will experience 60 - 100 mm rainfall per day. The maximum temperature will remain between 25-26C and minimum will come down to 23C.

For regular updates checkout www.vagaries.in

Margao crosses Century mark and other intersting statistics for SWM 2014

On August 26, 2014 Margao became only the third Rain Station in Goa to have crossed the Century mark in inches during 2014 SWM so far! Rainfall measured 119.8 mm during 24 hrs ending 0830 hrs on Aug 26th, helping Margao reach this milestone after Valpoi and Sanguem.

While Valpoi and Sanguem are at the base of the Western Ghats, the SWM performance in Margao this year has been remarkable.

While it appeared that Margao may be reaching the century mark by mid August, the monsoon break like situation which developed after August 15 meant Margao received just 108.6 mm of rainfall during 14 days from August 12 to August 25, less than what it received in a single day on Aug 26, 2014!

However rains have performed slightly better in Margao this year in August than in 2013. As seen in the chart below, till August 26,  Margao has received 26.72" compared to only 19.18" for the whole month of August in 2013!

However by August end 2013, the total rainfall for Margao had reached 114.82". Margao will have to receive 11" in the next 5 days to surpass it this year!

The overall situation of SWM for Goa as on August 26, 2014 is as below:

While the monsoon trough on the west coast is still active, the wind strength is low. While coming days may remain overcast, rains are forecast to be isolated and only occasionally heavy!

It will take a courageous weather forecaster to predict that Margao will surpass last year's total by August end!

Monsoon makes a comeback - though much subdued! Update August 25, 2014

After a week of sunny, clear skies with just nominal precipitation in most places in Goa, monsoon like weather was back in Goa from August 24.

The maximum day temperatures had climbed 4C above normal touching 32C. As shown in the IMD weekly analysis from 14/8/2014 to 20/8/2014, North Goa received nearly 50% of the normal rains only while South Goa fared a little better with deficiency of only 18%. Situation was even worse from August 20 to 24th.

However since August 24, a trough has become active off West coast which is pulling in the rain bearing clouds. But the monsoon winds at 850 hPa remain weak, resulting in isolated light showers at most places in Goa, bringing down the maximum day temperature by 4C to around 28C.

After recording just 13.9 mm total rains from 18th to 24th August, Margao Goa recorded 21 mm during 24 hrs ending 0830 hrs on August 25. Additional 12 mm were recorded at Vagaries Goa Rain Gauge at Margao from 0830 to 1900 hrs on August 25 and light rains are continuing. This has raised the exciting prospect of Margao reaching the 100 inch Century mark this monsoon season, after Valpoi and Sanguem, today itself!

More about it in the next post!

Goa - Mid August 2014 Monsoon Highlights

The beginning of August 2014 saw the momentum of widespread rains carry forward from July 2014. This was mainly due to active trough on the west coast as well as due to the presence of an active BB6 travelling westwards.

However the rains reduced significantly after the 10th and break monsoon like situation prevailed by 15th August, due to absence of west coast trough and any other significant systems. Mid August saw plenty of sunshine and few isolated heavy showers all over Goa. Rains are expected to return by last week August.

The highlights so far have been:

1. The overall rainfall deficiency is hovering around 15%, with area weighted actual rainfall recorded of 2066.7 mm against normal of 2434.1 mm for this time. A good showing in late August and September can further reduce the deficiency.

2. Valpoi crossed the century marks in inches and Sanguem leapfrogged Margao to occupy the second place also with a century! In fact Sanguem recorded more rainfall in August till the 15th than Valpoi. Panaji recorded just about 50% of the rains received by Margao, just 34 kms away, during the same time period!

3. However the 15 days of August provided almost the same amount of rains than the entire month of June for most towns, indicating the significantly deficient rains received in June 2014 by the state.

4. The following chart presents comparatively the month-wise cumulative rains across Goa:

5. The top five wet places in Goa till August 15, 2014 are as follows (cumulative rainfall in Inches):

Valpoi     - 117.06
Sanguem - 103.62
Margao   -   95.31
Sankhali  -   89.63
Canacona - 89.01

6. Margao daily rainfall chart shows the tapering of the rains by mid-August.

All India Monsoon Performance Snapshot - August 11, 2014

For once the dreaded 'D' word seems to be receding!

The performance of Monsoon in July and now continuing so far into August, has managed to bring down the National deficiency to -17%.

The All India Monsoon performance chart released by IMD for August 11, 2014 looks like this:

In fact, Odisha shows excess rainfall, thanks to BB5 and BB6. The flood situation is a real threat here!

The normal and deficient sub-divisions are almost evenly balanced.

Goa has a deficiency of -13%.

However the forecast released by Indian Institute of Tropical Meteorology, Pune, India had bad news for NW India for the remainder part of August.

Hopefully Goa will continue to receive its normal quota of August Rains!

August 2014 start promises to wipeout rainfall deficit

The start of the month of August 2014 has brought copious rains to all parts of Goa.

Aided by the activation of monsoon trough on the west coast and a deep depression BB6 travelling from Odisha westwards and now at the border of Rajasthan and M.P. the week ending August 6, 2014 saw nearly 50% excess rainfall in Goa as this chart from IMD, Goa Center indicates:

With this the seasonal rainfall deficit has come down to 15%. In IMD parlance normal rainfall is defined as +/- 19%! Thus this spell of rainfall has helped Goa reach the Normal monsoon range!

The daily Area weighted rainfall for Goa, also prepared by IMD Goa is helpful in gauging the daily variance:

The top three wettest places in Goa continue to remain:

1. Valpoi - 2722.9 mm (107.2 inches)
2. Sanguem - 2251.9 mm (88.7 inches)
3. Margao - 2159.7 mm (85.0 inches)

From Aug 1 to Aug 6 rainfall recorded at Valpoi and Margao was:

Valpoi - 411.4 mm (16.2 inches)
Margao - 201.7 mm (7.9 inches)

The trough is expected go remain active at least till Aug 8, bringing isolated heavy downpour in most parts of Goa, interspersed with bouts of cool sunshine!