Author Archives: Harley Pearman

Violent storms, wind and fires SE Australia 11th to 13th November 2016

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Violent Storms South Australia and New South Wales 11th to 13th November 2016

A significant weather event has crossed much of southern and eastern Australia which has impacted South Australia, Victoria, Tasmania, New South Wales, Australian Capital Territory and Queensland in different ways.sydneyradar12nov6am

The system has been responsible for producing thunderstorms, some of which have caused damage, gales, outbreaks of hot weather, some heavy rainfall, fires and even snow across higher alpine regions.

South Australia

During Friday, the fast moving weather system produced a few significant thunderstorms across South Australia and there were reports of large hail across parts of north east Adelaide.

Additionally, a weather station at Pinaroo recorded peak wind gusts of 128 km/h between 6.58 pm and 7.05 pm from passing thunderstorms.

Mildura – Victoria 11/11/16

Late Friday between 8.47 pm and 9 pm, a significant thunderstorm passed over Mildura (North West Victoria) dropping 27.4 mm of rain in 13 minutes. This is significant as it represents 2 mm of rain per minute. A closer analysis of this shows that between 8.51 pm and 8.54 pm (3 minutes), 10.8 mm of rain fell or 3 mm per minute and between 8.54 pm and 8.57 pm, another 10 mm of rain fell. Hence for 6 minutes, rainfall rates were in the order of 3 mm per minute.

This was accompanied with gales of 96 km/h. This storm has caused damage across the city with a clean up occurring.

Such a storm of this intensity is unusual given the location of Mildura within a semi arid region of the state.

New South Wales

A storm system passed through the Central West and there are reports of further significant thunderstorm activity Friday night / Saturday morning. Rainfall figures reached 30 to 50 mm across some locations of the Central West.

The system passed through Sydney early Saturday morning but no significant weather occurred. A single thunderclap was heard early Saturday morning being the remnants of storm activity that had reached the coast. Rainfall was not significant with most totals in the order of 10 mm.

Following the morning rainfall, maximum temperatures reached 34 to 35 degrees across much of the city as north west winds increased through the afternoon.

A late afternoon thunderstorm developed off the coast at Broken Bay to Sydney's north but moved quickly out to sea.

Thunderstorms occurred across the North west slopes of New South Wales and the Upper Hunter Valley and a number of storms were documented by storm chasers. One particular storm passed very close to the town of Narrabri with the airport receiving three wind gusts to 128 km/h between 5.33 and 5.39 pm Saturday afternoon.

Queensland Saturday afternoon

Thunderstorms produced some strong rainfall totals across parts of Brisbane including 67 mm at Mt Nebo Alert and 65 mm at Everton Hills Alert. In Redland, an intense thunderstorm produced 51.4 mm of rain between 3.24 pm and 4 pm which is a period of 36 minutes. Redland received 53.2 mm for the 24 hours to 9 am 13/11/16.

Tasmania

The same system has produced some heavy rainfall across eastern and north eastern Tasmania with the highest figure being 171 mm at Mount St John to 9 am 13/11/16. Additionally, much of northern coastal Tasmania received 54 to 89 mm during the same period.

New South Wales Sunday 13 November

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During Sunday, significant weather contrasts featured across New South Wales. In particular, while maximum temperatures reached 28C to 30C across Sydney, very cold air passed over Southern New South Wales thus places such as Albury experienced a cold wintry weather setup with constant showers and maximum temperatures struggling to reach 13C.

The same system has produced snowfall across the Mt Kosciusko region as freezing conditions set in for the passage of the system.

While this was occurring, a large bush fire occurred near Londonderry (North West Sydney) with fire fighters spending a number of hours fighting the blaze. At one stage, a thick plume of smoke emanating from the fire passed over Blacktown and south east blocking the sunlight. The fire was fanned by strong west to south west winds that reached 70 km/h at Penrith and 74 km/h at Badgerys Creek.

The system has produced a weekend of interesting weather contrasts with the one system creating numerous weather features depending on location.

Images

1 – Sydney radar image at 5.48 am 12/11/16. Despite the radar showing this, significant rainfall amounts did not occur.

2 - The Namoi radar at 5.30 pm. The storm at Narrabri is the one of interest as it is known wind gusts reached 128 km/h.

3 - Photo - Developing storm cell of Avalon / Broken Bay. This storm formed on the coastline and developed further as it passed out to sea.

4 and 5 - Photos - Bushfire smoke plumes west from Blacktown fanned by strong winds Sunday afternoon.

Hurricane Matthew nears Western Haiti 4 and 5 October 2016

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Hurricane Matthew threatening Florida

Hurricane Matthew continues it's slow movement north towards the western portions of Haiti. The storm is moving at 9 km/h northwards as a powerful Category 4 storm sustaining winds of 120 knots at the core with higher gusts to 140 knots (Approximately 220 km/h with higher gusts to 260 km/h).
cimssmodelformatthewThis is the most powerful storm since Hurricane Felix in 2007 and news reports already confirm 3 fatalities at the present time. Further fatalities cannot be ruled out especially across Haiti.forecastcone

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Path of Hurricane Matthew

Path of Hurricane Matthew

According to the National Meteorological Centre of Haiti, the Hurricane Matthew has a central pressure of 943 hPa. Hurricane winds are occurring within 45 km of the centre and storm force wind extend outwards to 315 km from the eye.

Western Haiti affected by Hurricane Matthew

The CIMSS forecast models suggests that the eye of Matthew would pass over the far western fringe of the country placing the towns / cities of Jeremie and Les Cayes at significant risk. Other smaller towns at risk include Dame Marie, Port A Piment and Tiburon

Haiti is an impoverished country and such a storm would have a significant impact and cause major disruption to the country.

Very heavy rainfall, storm surges and landslides are being forecast given the strength of the storm. The outer rain bands are starting to impact the southern coastal fringe of the country.

The western part of Haiti does not contain too many substantial towns or cities as shown on the “Urban Extents Map” but as shown on the population density map, the western side of the country is moderately to densely populated implying the region includes numerous small villages, farms, farming communities and rural towns. In this regard, the storm will have a major impact to the country.

The storm will also have a significant impact to eastern Cuba due to the number of large towns or cities within the region.

Forecasts are being made for rainfall to reach as much as 1,000 mm in isolated locations of Haiti which would cause landslides and serious flooding.

Forecast models suggests the storm emerging into the Bahamas within two days and traversing towards or close to Florida and possible impact within the Carolina's of the United States in six days. Major uncertainty exists beyond three days but it is clear that the whole south eastern sea board of the United States including the states of Florida, Georgia, South Carolina and North Carolina is now under threat from the storm. There is a possibility of landfall in eastern North Carolina in six days but this is to early to tell at the present time.

CREDITS

1 - CIMSS - Forecast model for Hurricane Matthew acquired 4/10/2016.
2 - National Meteorological Centre Haiti.
3 - National Weather Service (USA).
4 - NASA Worldview - Population plots for Cuba, Haiti and Jamaica.

Typhoon Chaba nears Taiwan October 3 to 5 2016

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The North west Pacific Ocean is clearly a region that favours powerful tropical storms. Barely days after Typhoon Megi made landfall across eastern Taiwan, another powerful typhoon has developed close to Taiwan. This time the storm is not forecast to make landfall on Taiwan.

Typhoon Chaba is travelling north but located approximately 500 km east of Taiwan as another powerful Category 4 storm on the Saffir Simpson Scale. The storm is sustaining winds of approximately 125 knots (Approximately 231 km/h) with higher wind gusts to 150 knots (Approximately 278 km/h) at the core. A well defined eye features on satellite photos with deep convection visible. Satellite photos also suggests an intense and compact storm.

The storm is forecast to reach peak intensity as a powerful Category 4 storm with peak wind gusts of 135 knots (Approximately 250 km/h) with higher gusts of 165 knots (305 km/h) and hence the storm could approach a Category 5 system at peak intensity as it moves north towards the Ryukyu Islands then towards southern Japan.

However, the storm is forecast to weaken once it starts to encounter more shear, cooler waters and land masses of Japan.

Sea surface temperatures of the region are around 29C to 30C but temperatures drop further north.

Forecast models suggests a weakening storm making landfall across Japan in coming days.

This shows how vulnerable the region is to such powerful storms. This is the forth typhoon that has reached Category 4 on the Saffir Simpson Scale within the past 30 days across the region.

CREDITS

CIMSS - Forecast plot for Typhoon Chaba dated 3 October 2016.
NASA Worldview – Satellite photo of Typhoon Chaba acquired 3/10/2016.

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