The special coverage of “widespread rainfall alert” by the Pakistan Weather Portal (PWP) is over!
Two strong eastern systems
One strong western trough
After experiencing a dull start to the monsoon of 2011, Pakistan is all set to get proper monsoon rainfalls that it used to get every year. Some parts of Pakistan had received above average rainfall while many parts faced below average rainfall. Early this year the United Nations (U.N) had published a report that suggested that probability of floods this year are high due to lack of construction in last year’s flood-hit regions, later a report from Oxfam international also reported the same things. But this year the monsoon rainfall were not active like last year mainly due to the lack of weather systems from the Bay of Bengal. Upper Pakistan has got showers due to the interaction between western troughs and monsoon moisture where as last year it was the interaction between strong western disturbance and a strong low pressure from the Bay of Bengal that created havoc in the country and later devastating floods sank 20% land of Pakistan. Now these same conditions are erupting as a strong low pressure is in making and a strong trough of western disturbance is over Afghanistan. Will history repeat itself?
PWP upgraded its second monsoon forecast from ” very high” to “extremely high” in Sindh, PWP on July 29 forecasted monsoonal activity in Sindh in August. PWP upgrades third monsoon spell for Sindh from “moderate” to “high”, PWP forecasted the third spell on August 4. Pakistan Weather Portal (PWP) is 75% confident with this forecast after observing different meteorological factors. But we may revise our third monsoon rainfall for Sindh.
Updates regarding Severe weather
All the new updates will be issued below;
Update issued on August 10 at 7:00 pm PST – LAST UPDATE
Yesterday’s low pressure area is over South Rajasthan and adjoining North-western Gujarat, it will enter Sindh on August 10 late or August 11 morning, the low pressure may intensify further into a well-marked low pressure area in 48 hours.
Under the influence of this strong weather system, widespread heavy rainfall to very heavy rainfall likely across Sindh especially south-eastern Sindh (Mirpur Khas, Badin and adjoining cities), while heavy rainfall likely in coastal Sindh too (Karachi, Thatta and Keti Bandar), overall the winds will be strong (56 to 60 km/h).
Update issued on August 10 at 2: 30 pm PST
Heavy downpour expected in 48 hours across Sindh
Yesterday’s low pressure area is over south Rajasthan now, it is likely to move into Sindh on August 10 late or August 11 mid-day/ (change has again occurred in its arrival date), the low pressure may intensify into a well-marked low pressure in next 48 hours.It will move to and fro over Sindh again as forecasted eariler.
Under the influence of this strong weather system, widespread heavy rainfall to very heavy rainfall likely across Sindh especially south-eastern Sindh (Mirpur Khas, Badin and adjoining cities), while heavy rainfall likely in coastal Sindh too (Karachi, Thatta and Keti Bandar), overall the winds will be strong (60 km/h), due to severe rainfall in Sindh, chances of flooding is likely. Rains as of latest forecast will start from today (have started in most parts)and last till August 14. While chances of rainfall in Karachi from evening (August 10).
Update issued on August 9 at 7:00 pm PST
“Chances of flooding in Sindh during the weekend”
Yesterday’s low pressure area is now over Madya Pradesh and adjoining Rajasthan, it has absorbed the upper air cyclonic circulations over Rajasthan and adjoining Punjab. The weather system will further intensify into a well-marked low pressure in next 48 hours, after that it might further intensify into a depression due to change in track the rains have been delayed in Sindh but not vanished.
The system will move from south-eastern to central to coastal Sindh and eventually head to Makran coast as it will be in dissipating stages on August 16. The system might enter Sindh on August 12 now instead of previous dates. Under the influence of this weather system very heavy rainfall likely in Mirpur Khas, Badin, Umerkot and other towns and cities of south-eastern Sindh with very strong gusty winds (60 km/h). While heavy rainfall with strong gusty winds likely coastal cities of Sindh that is Karachi, Thatta and other adjoining cities. Hyderabad will also get rain during this period. The rains will now start from August 12 morning till August 15 mid-day. The system could drop heavy sheets of rainfall in Sindh, thus chances of flooding in Sindh during the weekend. Light to moderate showers might occur on August 10 in different parts of Sindh mostly south-eastern Sindh.
Update issued on August 9 at 2:00 pm PST
Yesterday’s low pressure over north-west Mayda Pradesh it will further intensify into a well-marked low pressure in few days. Its track has changed since yesterday. It is likely to approach south-eastern Sindh on August 10/August 11, where it may further intensify. The system might will move to and fro over Sindh from August 10 till August 14 night, with strong intensity, during the period it will move towards upper Sindh then again to south-eastern Sindh and eventually from coastal Sindh to Makran coast on August 15.
Under the influence of this weather system, widespread rainfall with isolated very heavy rainfall with strong gusty winds (50 km/h to 60 km/h) likely in Sindh especially Mirpur Khas and Badin. Heavy rainfall also likely in coastal Sindh including Karachi from August 10 till August 14 night with few gaps. The system will head towards Makran coast on August 15.
Update issued on August 8 at 10:00 pm PST
Low pressure over north-west Madya Pradesh persists, it may further intensify into a well-marked low pressure in next few days. It will follow a NW track towards upper Sindh and adjoining south Punjab instead of SW track. However change in track may occur in 24 hours after that no change likely.
Under the influence of this weather system, heavy to very heavy rainfall likely in upper and some parts of south-eastern Sindh including Sukkur. While the intensity of the rain will be heavy in coastal Sindh including Karachi. Winds are likely to be strong especially in upper and south-eastern Sindh where some wind storms may occur. Rains will start from August 10 and continue till August 14.
Update issued on August 8 at 3:00 pm PST
Yesterday’s UAC over Utter Pradesh has intensified into a low pressure area at present it is over north-west Madya Pradesh and adjoining areas of Utter Pradesh. The low pressure will further intensify into a well-marked low pressure area (strong weather system) before reaching Pakistan, it will maintain its intensity for few days. The system is now likely to move in a west direction according to GFS (towards south-eastern and Upper Sindh), instead of south-eastern Sindh and coastal Sindh to Makran coast.
Under the influence of this weather system, heavy to very heavy rainfall with very strong gusty winds likely across Sindh from August 10 to August 12 night/August 13 mid-day.
Update issued on August 7 at 9:00 pm PST
The upper air cyclonic circulations (UAC) over Utter Pradesh is likely to intensify into a low pressure in next 2 days (August 8 or August 9) now, it will acquire a south-west track before reaching Sindh on August 10/August 11. Certain models suggest it to intensify into depression, but it is more likely to become a low pressure or well-marked low.
Under the influence of this weather system, heavy to very heavy rainfall with strong gusty winds likely in Sindh from August 10 to August 12 night/August 13 mid-day.
Features of the weather systems
Below is the features of these weather systems (they may change as time passes by);
First low pressure
An upper air cyclonic circulations formed in the central Bay of Bengal on July 28 that moved to north-west Bay of Bengal the same day, the UAC persisted over the north-west region of the Bay for many days. On August 2, the UAC moved to northern part of Bay of Bengal but the other day it once again headed to north-west Bay. After many days of stationary movement, the UAC on August 4 crossed the Orissa coast and late that day it entered Chhattisgarh. On August 5, the UAC moved to Utter Pradesh and the other day it moved to south-east Utter Pradesh. The UAC is currently moving in south-west direction after moving in a westwards direction. The Upper air cyclonic circulations are forecasted to intensify further, it will move from Utter Pradesh to Gujarat via Rajasthan and enter Sindh by August 11 morning/evening, it will completely enter Sindh on August 12 evening. It is very likely that this UAC will start to gain intensity to become a low pressure/well-marked low pressure on its way to Sindh. Very few models had went so far in suggesting that it would become a depression over land, that is something that is extremely rare. Overall the intensity of this system will be very strong.
Trough of western disturbance
On August 4, a western trough over the Afghanistan started moving towards Pakistan slowly, on August 5 it gained intensity and moved to north-east Afghanistan. It is currently moving in westwards towards Upper Pakistan. Interaction between western trough and strong monsoon moisture will take place in coming week in Upper Pakistan as forecasted by Pakistan Weather Portal (PWP)
Second low pressure
Although it is too early to go in detail about this weather system but what PWP had observed about this system, PWP will share with its readers;
An upper air cyclonic circulations form over the Bay of Bengal and move inland on August 14 to Madya Pradesh, it will also move westwards. If it behaves as forecasted then it will bring the third spell to Sindh, if it is the opposite that no third monsoon rainfall in Sindh. Few days back, various meteorological parameters observed by the PWP showed that it will become a strong weather system (Low pressure) over Madya Pradesh and head towards South Punjab and upper Sindh. Whenever it forms or what ever track it selects, PWP will give updates.