Pakistan has now entered the month where temperatures decrease rapidly across the country unlike in November. Cool systems became more frequent over northern parts of the country while south-eastern parts mainly remain dry but also could not escape the cool winds.
Major factors affecting Pakistan now
*Fresh western disturbance over northern Pakistan and adjoining area; likely to stay for 2 to 3 days.
*Dry weather to persist in southern parts of Pakistan.
*Fog in the plains of Punjab and Khyber to ease during the current week.
Fog will ease but return!
Fog conditions in the plain areas of Punjab and Khyber are likely to subside from December 20 but will redevelop over the same areas after the western winds move in a NE direction.
Karachi sweats first then shivers!
Karachi after witnessing some unusual warm days of December due to tropical storm ARB 04 that brought moist winds, the city is now under the grip of cold wave. December of 2011 as it leaves us, set the highest temperature in Karachi on December 2 that was 35 °C, highest in Karachi since record keeping began. Following is the list of lowest temperatures during the last few days in Karachi;
- 11 °C recorded on December 19,
- 10 °C recorded on December 18.
- 9 °C recorded on December 17, The lowest of this day was 7 °C in 2005.
- 10 °C recorded on December 16.
- 11 °C recorded on December 15.
The low temperatures have slightly risen since few days but with the approachment of western disturbance 11, the temperature would go done again mainly from December 21. Early morning mist has also developed over the city due to dry air that is likely to stay for few days. There are no chances of rainfall in the current week in the city. However the last week is somewhat unsettled for Karachi.
Cold wave to gain intensity
Northern Pakistan is once again all set to feel the Siberian winds that are once again tracking towards Pakistan. There are greater chances of light rainfall/isolated moderate in Islamabad, Peshawar, Gilgit, Malakand, Hazara, Muzaffarabad and other surrounding areas on December 19 night till December 20 night. Western disturbance 11 has caused isolated heavy rainfall in north-eastern Afghanistan but its intensity has weakened by the time it entered Pakistan, however showers will be accompanied by fast winds. However the most rain-bearing part will be over the northern borders of Pakistan and they will gradually move eastwards as WD 11 moves out of the country, but the cool winds will keep penetrating into the country. The cool winds have also entered Gujarat, Rajasthan, East Punjab and Haryana states of India. The Siberian winds have also engulfed Sindh and south Punjab.
In Karachi, the night temperatures would range from 10 °C – 7 °C till December 25 and then it will start to rise slowly.
Eye on Winter: Western disturbances
There had been total of eleven western systems from October till now; with little to moderate precipitation;
- Western disturbance 01 affected upper parts of Pakistan from October 5 to October 8 with strong gusty winds (76 km/h in Islamabad/Rawalpindi). In terms of strength this system was much stronger than the rest of waves that followed after. The rainfall was mostly light with isolated moderate falls.
- Western disturbance 02 affected north-western Balochistan province including from October 10 till October 11. The rain was light in intensity.
- Western disturbance 03 affected upper parts of Pakistan from October 13 night till October 14 morning. The winds gusted to 48 km/h in Islamabad/Rawalpindi, the rainfall was weak in intensity and isolated.
- Western disturbance 04 affected Northern Pakistan from October 20 till October 23 night, temperature dropped by 3°C to 1 °C, 79 km/h winds were blowing in Islamabad.
- Western disturbance 05 affected extreme Northern Pakistan from October 28 till November 1.
- Western disturbance 06, shallow in nature affected upper parts from November 2 till early November 3.
- Western disturbance 07 , a large westerly wave in nature affected central and upper pats from November 8 morning till November 10, it trough interacted with deep depression ARB 03.
- Western disturbance 08, a feeble system, approached northern Pakistan on November 15 and moved in an eastern direction on November 19.
- Western disturbance 09, a shallow weather system, approached Pakistan on November 21 and caused isolated snowfall in Swat valley.
- Western disturbance 10, first weather system of December,moved towards Pakistan from December 5 and persisted till 8. It caused first winter showers in Lahore on December 6.
The second western disturbance of December (WD 11) has been persisting over northern Pakistan from December 19 morning with high and mid cloud cover over western central and northern parts of the country, the wave will exit Pakistan on December 21 night/December 22 morning. Another chilly days coming!