Skymet weather

Why Hurricanes after Hurricanes?

The storm season in the Pacific seems to have woken up. Suddenly storms seem to be sprouting up one after another including the Atlantic Sea. But having two storms arriving nearly on top of one another, and travelling along roughly the same track, is fairly unprecedented.

storm poloJust days after Hurricane Odile left trail of damage in Baja California, Mexico, Hurricane Polo followed closely. Polo strengthened from a tropical storm to a hurricane Wednesday evening after moving into favorable atmospheric conditions.

 

 

 

Both tropical storms became hurricanes off Mexico’s Pacific coast and as they raced towards the state, the intensity of the storm toned down.

On the other side, Hurricane Edouard is beginning to weaken as it moves quickly northeast in the North Atlantic, over 1000 miles east of Bermuda. However, swells originating from Edouard have created dangerous surf along the East Coast of the U.S. After reaching its peak two days back, Edouard began its weakening trend as the hurricane moved into an area of unfavorable conditions.

Reasons for Formation

One possible reason for the quick formation of these storms is the temperature of the water in the Pacific Ocean right now. There is also El Niño in the works right now, with warmer sea surface temperatures, but a somewhat sluggish response from the atmosphere.

Tropical cyclone basins have a seasonal pattern and the activity peaks in late summer when the difference between the temperature aloft and sea surface is large. High levels of heat potential and sea surface temperature exceeding 26 degree centigrade are the essential requirements towards the formation of cyclones.

Hurricane season endures from June 1 to Nov 30 and peaks from late August through September.

There are six main requirements for Hurricane formation:-

  • sufficiently warm sea surface temperatures
  • atmospheric instability
  •  high humidity in the lower to middle levels
  • enough rotation to develop a low pressure center
  • a preexisting low level  disturbance
  • and low vertical wind shear

 

 

Effects of Hurricanes

The elevated surf and the threat of dangerous rip currents are the common hits that aftermath of these hurricanes leave behind. This means more heavy rainfall, driving winds and possible flash floods.

Country deficit increases to 12%, drought conditions still remain

DROUGHTAs reiterated by Skymet Meteorology Division in India, the cumulative rainfall deficit which was 11% on 7th of September stagnated for almost ten days (till 6th September) and failed to recover eve once during this time. In fact the deficit has increased and stands at 12% at the moment.

This has already raised concerns amongst weathermen who are keeping an eye on the cumulative rainfall deficit and fear a drought. The most essential condition amongst other weather parameters to declare a drought is that the rainfall deficiency should be 10% or beyond, which is exactly the case here. And with only 10-12 days left for the country to observe some more active monsoon conditions, the recovery does not look possible.

Drought Category

Mild drought: -11% to -15%
Moderate drought: -16% to -20%
Severe drought: -20% and above

However, there is some positive news on this front. According to the latest weather update by Skymet Meteorology Division, there are chances of some good rain in Northeast India from Septmeber 20, which is likely to last for 3-4 days. Amounts of rain in the Northeast are usually erratic and the forecast of good spell in the region could see National cumulative deficit slip to 11%. But on the other hand the Southwest Monsoon has begun its withdrawal from Northwest India due to which the rainfall amounts have become almost nil, adding to the cumulative deficit. Therefore, the spell of rain in Northeast India will play a vital role in affecting the deficit percentage.

Recently, the state government of Haryana was forced to declare the state drought-hit and demand compensation from the Centre. Following suite is Uttar Pradesh government that has declared 44 of its 75 districts as drought hit. Haryana is one of the worst rainfall sub-divisions in the country.

The onset of Monsoon in India had been very poor and the cumulative deficit in June was a whopping 43%. It recovered in July to record 22%, courtesy some good rain during the last two weeks of the month. In August the recovery was even better with the cumulative deficit recording 18%, since then the improvement has been slow.

Picture courtesy: thehindu.com

 

Withdrawal of Southwest Monsoon commences from west Rajasthan

SW MONSOON WITHDRAWAL_17SEPSouthwest Monsoon in India is conceived as a complex phenomenon. A cautious approach is generally taken before announcing onset or withdrawal. Just as the onset is eagerly awaited, even withdrawal is keenly followed.

Withdrawal symptoms of Southwest Monsoon are clearly visible now. According to the latest weather update, seems like it has already commenced from west Rajasthan.

Monsoon in India

Monsoon season spans over the Indian region from June to September and holds a Long Period Average (LPA) of 89 cm of rain. It has few built-in features like the calamity over Uttarakhand in 2013 and the floods in Jammu & Kashmir this year. Monsoon never behaves in a normal manner, as rainfall distribution mostly remains uneven both in space and time. It always leaves one guessing as it brings anxious moments, anticipatory worries and jitters.

July and August are generally the active Monsoon months for the entire country. June is the onset month which witnesses an outburst of rain while, September is the withdrawal month, receiving more of sporadic rain.

Withdrawal of Southwest Monsoon

Withdrawal is generally not attempted before 1st of September and commences from extreme west Rajasthan. A shortfall of Monsoon brings a host of problems, similarly even delay of withdrawal damages crops.

As Southwest Monsoon approaches the withdrawal phase from a particular region, certain conditions become prevalent- change of wind pattern, reduction in cloud cover, decrease in humidity, cessation of rain, appearance of dew and reduction in temperatures.

Reversal of wind pattern- Winds over Rajasthan have already turned westerly, indicating replacement of moist air by cool and dry air.

Cessation of rain- Bikaner, Barmer and Bhuj have been completely dry since last 12 days. Jodhpur and Jaisalmer have not received any rain since last 6 days.

Dip in humidity- Humidity across west Rajasthan has come down from 85-90% in first week of September to 75-80% at present.

Establishment of anti-cyclone- In Northwest India winds have started blowing in clockwise direction but proper establishment of anti-cyclone takes more time. At present the winds have given rise to a ridge i.e. clockwise movement of winds without making a proper circle.

Monsoon trough- Monsoon trough is lessmarked and has shifted closer to the foothills and is likely to remain there.

Monsoon Index- It is the pressure difference between Trivandrumand Mumbai. At present the pressure difference has reduced to 0.9 hPa against the normal of 3 to 4 hPa during active Monsoon period.

Status on September 10

Name of Place Minimum in oC Dew Point Humidity in % Sky condition
Sri Ganganagar 27 26.2 95 Partly Cloudy
Bikaner 27.2 23.1 78 Partly Cloudy
Jaipur 26.2 24.5 90 Partly Cloudy
Jaisalmer 27.8 24 80 Partly Cloudy
Barmer 27.4 24.5 84 Partly Cloudy
Udaipur 24.4 22.7 90 Partly Cloudy

Status on September 17

Name of Place Minimum in oC Dew Point Humidity in % Sky condition
Sri Ganganagar 26 23 83 Clear
Bikaner 26.6 21.2 72 Clear
Jaipur 25.8 21.6 78 Clear
Jaisalmer 25.8 21.6 78 Clear
Barmer 27.4 21.7 71 Clear
Udaipur 23.4 21.6 90 Clear

 

From the above table it is evident that the period of retreat of Monsoon has started from west Rajasthan. The figure above clearly shows that it has retreated also from Kutch, parts of Punjab and Haryana. Gradually monsoon will retreat from Jammu and Kashmir, Himachal Pradesh, Uttarakhand, Delhi/NCR, west Uttar Pradesh, east Rajasthan and Gujrat in next few days.

 

Weather in hills of North India turns pleasant with withdrawal of monsoon

Weather in ShimlaWith the onset of withdrawal phase of Southwest Monsoon, the hill stations of North India will witness pleasant weather conditions, making it a perfect time for tourists to visit these places. Northern states of Himachal Pradesh and Uttarakhand are quite famous for their hill stations that include Shimla, Manali, Nainital and Mussoorie.

Known for their mesmerising and scenic beauty, these hill stations attract thousands of tourists every year. According to Skymet Meteorology Division in India, prevailing weather conditions in these areas are conducive for tourists, as there is no threat of rain. Temperatures are also soothing, neither too cold nor too warm. Moreover, accessibility to these hill stations is also good, without any fear of land slide.  At present, tourists have enough daylight for sightseeing. Let us have look at weather conditions for these hill stations for next 48 hours.

Shimla and Manali, Himachal Pradesh: Shimla is situated at a height of 7200 ft, while Manali is located at a height of 6726 ft. As per Skymet, both the towns have been observing maximum temperature of 25°C that is around normal, while minimums have been recording between 10°C and 13°C. The weather conditions are expected to prevail for the 48 hours, with a marginal change in temperatures. There will be least cloud cover and rain will be minimal. Tourists will continue to enjoy this comfort zone for another fortnight before temperatures start dipping, particularly during night.

Nainital and Mussoorie, Uttarakhand: Located at a height of over 6000 ft, these hill stations are quite famous as weekend gateways. According to Skymet, no rainfall activity was recorded in these hill stations during the past three days. Maximum temperature has been hovering in the mid twenties, with minimum settling between 10°C and 15°C. These hill stations have been witnessing good weather conditions, making it conducive for tourists' stay and will continue on the similar pattern over the next 48 hours.  No major interruption on account of weather is expected for another week or 10 days.

 

Baja California in for yet another storm

storm poloJust days after a severe tropical storm Odile battered the Baja California peninsula, Tropical Storm Polo is forecast to follow suit.

As if the damage caused by storm ODILE was not enough, storm Polo has been seen trailing fast. Tropical Storm Polo is moving Northwestwards, parallel to the Mexican Pacific coast, where tropical storm watches have been issued.

Though the core of the system is expected to stay offshore, strong winds, heavy rain, high surf and rip currents may eventually affect portions of the coast, including the resorts of Acapulco and Ixtapa.

The current thinking is that building high pressure aloft over northern Mexico may help turn Polo toward the west-northwest, away from the southern Baja peninsula.

Storms pile up back-to-back

Hurricane Odile has created history of sorts as it goes into the record books as the strongest tropical cyclone on record in modern recordkeeping on Mexico's Baja California peninsula.

odileThe Category 3 storm made a direct hit on Cabo San Lucas, a popular tourist destination, on Sunday night leaving tourists stranded and shops open for robbery.

The hurricane's most severe impacts were in the municipalities of Los Cabos, which includes both Cabo San Lucas and San Jose Del Cabo, and La Paz, which lies north of Los Cabos and is the capital of Baja California Sur. The grazing of the storm with the land has caused widespread power outages, flooding and wind damages.

However, Baja peninsula, which is still recovering from the devastating Hurricane Odile, is currently reeling under uncertainty about the tropical storm Polo becoming a hurricane. It was located about 285 miles south of Acapulco and had maximum sustained winds of 40 mph is expected to strengthen into a hurricane later this week.







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