This article was originally published on Pakistan Weather Portal (PWP)

PAKISTAN WEATHER PORTAL – Since the forecast of a possible cyclone in the Arabian sea emerged on May 23, there had been much talk about its possible track and intensity. Cyclones in the Arabian sea are rare and stronger ones are extremely rare but not unheard. A little disturbance in the Arabian sea sends chills to the coastal localities of Pakistan, Western Indian and Oman.

Pakistan is a country which rarely gets to see cyclones before and after the monsoon season, while the eastern India gets the highest number of cyclone than any part of the North Indian Ocean. Oman on the other hand, well, cyclones are rare guest in this small Arabic state but since past few years there had been greater than usual tropical disturbances in Oman. The reason? global warming and high sea temperatures than usual, and the frequent number of extra-tropical waves (western disturbance) over Northern Sub-continent that blocks the cyclones from moving in a Northern direction.

Expected track of ARB 01 or Keila

It is still unknown whether this storm will become a cyclonic storm or just intensify into a depression/deep depression. Since the past few days, the GFS model has been predicting a Pakistani landfall but during the last few days its showing a landfall in Oman. Some models also show that Gujarat or Gujarat-Maharashtra coast is the target. It is worth mentioning that one of these tracks will definitely come true in the days ahead as this area of thunder showers is expected to become a depression on June 1 or June 2. Following are some of the expected land threatened by Keila or ARB 01;

1.  Oman.
2.  Pak-Indo coastal border.
3.  Sindh in Pakistan.
4.  Sindh-Balochistan in Pakistan.
5.  Gujarat- Maharashtra coast in India.

The most likely landfall of ARB 01 is Oman as the western disturbance is expected to approach the Sub-continent on June 1. Conditions near the road to Oman will also be favourable that is low wind shear. There is already a lot of moisture over Arabian sea that will keep fueling the system. Therefore Oman is likely to be the final resting places of ARB 01.

Has Oman seen cyclones or depression in this time of the year? In short, Yes. But there had been also some errors in prediction of these storms. lets take a look;

Past first week tropical depressions of Arabian sea

Cyclone Gonu 2007

• First and final prediction – It was always forecasted to make landfall in Oman. But Gonu was not expected to become a category-5 Super cyclone, thus breaking all past records.

Cyclone Phet 2010

Phet formed on May 30 and dissipated on June 7.

• First prediction - Phet was expected to hit Gujarat and adjoining Sindh as a category-2 hurricane.
• Second prediction - In second warning, Phet was expected to hit Sindh and adjoining Gujarat as category-3 hurricane.
• Third prediction - In the third warning it was expected to hit Karachi and Sindh as a low-end category-3 hurricane.
• Fifth and final prediction - In final warning, Phet was expected to hit Oman as category-5 hurricane but in fact the storm hit Oman as category-4 and then re-curved back to Pakistan and India as a weak depression.

ARB 01 and 02 2009

Though these two storm did not form during the first week of June but they were the first Arabian sea depressions of 2009.

ARB 01 formed on June 23 and dissipated on June 25, it formed near Mumbai and moved from Gujarat to Sindh, it caused rainfall in Karachi and Gujarat, while its remnants helped give life to another depression called ARB 02 that kept moving on open sea waters till it also dissipated on June 26. ARB 01 had winds upto 30 mph and it dropped 100 mm rainfall in Jamnagar, Gujarat.

ARB 01 2008

It formed on June 5 and dissipated on June 7. It was a depression with winds upto 30 mph. It was also forecasted to intensify into a deep depression then into a cyclonic storm . It was also first forecasted to hit Sindh-Gujarat border but it went to Oman as a well-marked low pressure area.

So is it 2008 OR 2009?

Will ARB 01 2011 follow 2008 path and bring rainfall to Oman? or Will it follow 2009 path and bring showers to a city that received last proper rainfall on September 13? This question will be answered on June 1.

If ARB 01 2011 hits Oman then it will be the third year that a tropical depression formed in the Arabian sea during the first week of June and made landfall in Oman.