ASIA EXTREMES: Saudi Flash Flooding, Iraq’s First Recorded Tornado, Pre-Monsoon Heat In India, Thailand, Vietnam

Written by on April 15, 2016 in Asia, Spring 2016 with 0 Comments

The 2016 El Nino has dominated the entire global weather circulation, driving the warmest winter on record for some across the Northern Hemisphere.

However, it’s vast influence isn’t waning despite the El Nino waning with waters cooling dramatically off South America’s west coast. As expected in a Super El Nino’s weakening phase, a large low pressure system crossing the Arabian Peninsula into Iran and Iraq has been dropping torrential rainfall which has resulted in flash flooding across large parts of Middle East including Saudi Arabia, Oman, Qatar, Iraq, Iran.

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Flooding in Riyadh, Saudi Arabia.

Municipal workers pump water from a flooded street in Riyadh after heavy rainfall across the Saudi capital. Fayez Nureldine / AFP Photo

Municipal workers pump water from a flooded street in Riyadh after heavy rainfall across the Saudi capital. Fayez Nureldine / AFP Photo

Flood waters in Yemen.

A motorist drives in floodwaters after a heavy rain in Sanaa, Yemen on April 13, 2016. Hani Mohammed/ AP Photo

A motorist drives in floodwaters after a heavy rain in Sanaa, Yemen on April 13, 2016. Hani Mohammed/ AP Photo

A rainy day in Dubai.

Dubai received some rain on Tuesday afternoon. Satish Kumar / The National

Dubai received some rain on Tuesday afternoon. Satish Kumar / The National

Blinding rains in Riyadh.

Scary video shows true power of flood waters in Saudi Arabia yesterday.

Iraq (Mesan, Halfaya) even experienced it’s first tornado in recorded history yesterday!

Credit: syazana ‏@syazana_zafirah

Credit: syazana ‏@syazana_zafirah

Credit: syazana ‏@syazana_zafirah

Credit: syazana ‏@syazana_zafirah

More storms influencing Middle East today but drying out this weekend.

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Like there’s a lag between time of year and weather/climatic patterns, there’s a lag in the influence of El Nino also and atmospheric pressure is lower and air cooler than normal. Meanwhile, this is leading to extreme heat across the Asian sub continent extending east across Thailand, Vietnam and Cambodia.

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This is a sure sign of El Nino’s vast influence on the atmosphere world wide and the above normal rainfall over the Middle East and lower than normal rainfall over India means a likely above normal monsoon season following 2 years of below normal rains and drought.

This build up of heat occurs every year ahead of the monsoon but it’s earlier than usual, signalling an above normal monsoon which impacts 80% of the Indian economy, impacting over 1 billion people.

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An interesting read about the Indian monsoon.

The pre monsoon heat builds over India

In early April the sun is at the same height in the sky as it is in late August and in the next few 2 months one of the worlds most important and fascinating meteorological phenomenon occurs, the SW Monsoon.

The SW Monsoon occurs every year across India and South East Asia. It is extremely important not only meteorologically but also economically with millions depending on the rains occurring where they should to bring wealth and prosperity to the whole region.

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But what is the Indian or SW monsoon and how & why does it occur?

The weather across Asia is infact driven by two monsoons. The lesser talked about Northeast monsoon and the much greater known SW Monsoon and both are driven by the presence, strength and positioning of high & low pressure which develops each summer and winter over the great Asia landmass.

During April and May each year as the earth tilts on its axis, the Asia continent like the rest of the northern hemisphere heats. As this heat builds, the high pressure which sits over greater China, Russia and northern India declines and is replaced by falling pressure and eventually low pressure.  The is because heat rises and as the heat builds and builds air must move in the compensate for the air which is rising (much like a giant sea breeze affect)

The winds over India and SE Asia blow from the NE during the winter around a high located over Mongolia, Western China and central Russia.  During April and more particularly in May these winds collapse as the high weakens and the heat bakes India & Pakistan and to a lesser degree Thailand, Western Vietnam, Myanmar, Nepal and Bangladesh.  Temperatures will climb initially into the high 30s, then low 40s and in some years mid to high 40s.  Pollution in India’s largest cities increases and the heat becomes stifling to those not accustomed to the annual cycle.  The heat building is a sign that the monsoon is on the way.  But where does it come from ?

The Monsoon originates from the Inter Tropical Convergence Zone (ITCZ) over and to the west of the Andaman and Nicobar islands and to the SE of Sri Lanka.  As the sun moves north or the earth reaches its maximum tilt the ITCZ is forced north in tandem.  At the same time a low level Jet Stream develops off the coast of Somalia in Eastern Africa and it is this jet which is vital for the advance of the SW Monsoon.  Coupled with this jet, pressure falls over India, the Arabian Sea, Bay of Bengal and over Thailand and Myanmar.

Isolated thunderstorms normally begin to break out during May over India esp the east and south east and gradually as time progresses these storms become more widespread.  However it is usually not until late May or early June that the monsoon really kicks off.   By the 1st week in June low pressure should be forming off the coast of Kerela in SW India and the Somali jet should be getting stronger.    The Monsoon now begins.

During the rest of June – the monsoon will move Northeast but it actually advances and withdraws NW/SE.  It’s progress finally reaching Pakistan, NW India in late June or early July where it will persist for just 4-6 weeks before it begins to retreat.

The monsoon rains are highly unpredictable and the rainfall is highly variable between states.  The monsoon is often heaviest across Kerela, Andhra Pradesh, Maharashtra & Karntaka.  Mumbai receives nearly its entire annual rainfall between late May and mid September.  Amounts of rain are often huge with up to 1000mm or 1m of rainfall occurring during a day or two.  A weeks rain can bring up to 5-8m of rain in the worst years.   Flooding occurs and travel becomes difficult for millions across SE Asia.

In some years monsoonal lows can develop which enhance the rain and can bring deluges of rain. Cyclones can develop in the Bay of Bengal and Arabian seas.  These can bring devastation and destruction.

New Delhi and Karachi receive their monsoon rains a little later than Mumbai and it’s often not until the second half of June before the rains reach Delhi and early July before Karachi receives anything substantial.   These will be the only rains that these areas receive, so if the monsoon is weak or in worst cases fails to reach these N and NW parts then it will be a long wait until next year.

The monsoon is highly unpredictable and many scientists have attempted to trace linkages to El-Nino, La Niña and the Indian Ocean dipole affect but there remains a lack of understanding as to how strong or weak the monsoon will actually be.  One thing is clear – it is one of the planets most phenomenal and powerful weather events which without it would leave millions facing starvation and would leave India largely a desert.

So what of the 2016 monsoon ? Forecasters at the Indian Meteorological Department (IMD) are forecasting a better than average monsoon in 2016 with better and more widespread rains than in 2015.  The negative effects of El Niño and the positive Indian Ocean dipole will largely have been eliminated by the summer according to the clime prediction models run by the Australian bureau of meteorology, NOAA and the ECMWF.  Heat is already building with highs in the low 40s already having been reported across parts of central India…

Over the coming 6 weeks the heat will build even further and eyes will begin to look to the SW for those ominous but highly welcome thunderclouds gathering off the Kerala coast which will herald the onset of this years monsoon …

Written by Paul Blight – 6th April 2016

We will track the monsoon over the coming weeks and later this year we will discuss the withdraw of the SW monsoon and its lesser talked about brother the NE monsoon.

Heat to continue…

Credit: Tropical Tidbits

Credit: Tropical Tidbits

Credit: Tropical Tidbits

Credit: Tropical Tidbits

Credit: Tropical Tidbits

Credit: Tropical Tidbits

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