The 2009 Atlantic Hurricane Season officially began on the first of June, and we are yet to experience a named storm. Many people may be wondering why this is occuring, we can quickly look at the weather pattern currently in the United States. The tornado season which generally occurs between March and June each year and peaks in late April and May, this year the tornado season seemed to peak late and June saw numerous tornadoes, over-all it was a quiet season but can we expect the same from the Hurricane Season. The conditions needed for tropical development occur in summer in the United States which cold fronts no longer dip down south and thus the environment is not as sheared. Overall conditions in the Atlantic haven't been prime but there haven't been many tropical waves crossing the Atlantic and thus less chances for tropical development.

Looking ahead the long range GFS model has been showing hints at a Cape Verdes system developing in around 8 days time. Though this is still long out on the time frame and many 'phantom storms' like these occur each year without bringing any real results. For those hurricane trackers out there, there is a little bit of hope in the models. Granted we are over a month into the season without a storm but as was seen in the case of Hurricane Andrew in 1992, it only takes one. 1992 was a below average hurricane season but brought with it one of the strongest hurricanes of all time making landfall as a category 5 storm.

The other talk on the tropical boards is the presence of El Nino this year, El Nino years have been linked to lower numbers of hurricanes forming. Below is the latest official BoM update on the possible El Nin:

"The central and eastern equatorial Pacific sea surface warmed through June. This warming was a continuation of a steady warming trend that has been observed since February 2009. Weak warm SST anomalies are now well established across most of the equatorial Pacific. The monthly indices for May were +0.6°C, +0.4°C and +0.4°C for NINO3, NINO3.4 and NINO4 respectively. The monthly indices for June will be calculated early next week.

In terms of weekly data, the most recent NINO indices are +1.0°C, +1.0°C and +0.7°C for NINO3, NINO3.4 and NINO4 respectively. Over the past two weeks the SST has warmed in all three regions. NINO3 has warmed by approximately 0.2°C, NINO3.4 by 0.5°C and NINO4 by 0.3°C. The 7-day SST anomaly map shows the persistence and further development of positive anomalies across most of the central and eastern equatorial Pacific when compared with two weeks ago. Anomalies of greater than +1.0°C are now evident across most of the central and eastern equatorial Pacific on a weekly scale. An animation of recent SST changes is available.

The sub-surface of the equatorial Pacific has also continued to steadily warm through June. A large volume of warmer than normal sub-surface water is evident across the entire tropical Pacific. A recent map for the 5 days ending 28 June shows the warmer than normal sub-surface water extending across the equatorial Pacific. Sub-surface anomalies exceed +2.0°C across most of the central and eastern tropical Pacific, with a small area of water where anomalies exceed +4.0°C evident between 130°W and 100°W on a weekly scale. An animation of recent sub-surface changes is available.

An archive of past SST and sub-surface temperature charts is available.

The Trade winds were weaker than normal across much of the equatorial Pacific during June, especially in central and eastern areas. During the past week or so, easterly anomalies have become established in the western tropical Pacific; this is likely to be assoiciated with the recent rise in the SOI. Trade flow is generally slightly stronger than it was two weeks ago across the central to eastern Pacific as well. The latest weekly wind anomalies are shown in the TAO/TRITON map (small image above) for the five days ending 28 June.

The Southern Oscillation Index (SOI) fell sharply through the first three weeks of May. The SOI dropped to an approximate 30 day value of −11 on the 22 May after an April value of +9. Recently the SOI has increased to a current (29 June) approximate 30 day value of −2. (SOI graph, SOI table). If model predictions of a developing El Niño are correct, the SOI would be expected to fall again, that is, become more strongly negative.

Cloudiness near the date-line over the central to western Pacific is another important indicator of warm/cool ENSO conditions, as it normally increases/decreases (negative OLR/positive OLR anomalies) during these episodes. Cloudiness near the dateline has increased recently, from below average to near-normal. Although cloudiness near the date-line has been increasing, it is yet to show a clear trend towards El Niño conditions.

All international dynamic computer models surveyed by the Bureau of Meteorology predict further warming of the Pacific Ocean SST in coming months. All models predict SST to be above El Niño thresholds throughout most of the second half of 2009. One of the surveyed models has slower weaker warming than the other five, but all six models predict El Niño conditions to be established by the southern spring at the latest. As all models agree in the development of El Niño conditions and predictability of El Niño conditions is high at this time of the year, the probability of an El Niño event occurring in 2009 is high; a definite increase from a month ago. Recent forecasts from the POAMA model, run daily at the Bureau of Meteorology, show a steady warming with El Niño conditions developing in July. Pacific conditions and model predictions will continue to be monitored closely."

http://www.bom.gov.au/climate/enso/

In similar fashion as to what happened in Cape Town just a few months ago, the media was all over the skies again- but this time in New York. People were rushing out of hotels and apartments into the streets to take pictures of the rare mammatus clouds which at sunset lit up creating an unusual and ominus feel. Usually it is only those interested in weather itself that find themselves gazing at the sky in awe but it seems if there is one thing that gets the public's attention it's mammatus clouds. CNN even went as far as to broadcast a report on the clouds and seeing 'Michael Jackson' in the formations.

While the United States is no stranger to severe weather, these unusual clouds are still rare in the plains and even rarer in New York. Mammatus can form both on the bottom of dying thunderstorms as well as under alto-cumulus clouds given the environment is perfect for their formation.

For more on mammatus clouds be sure to check the article on Mammatus Clouds in Cape Town.

As the final cold front exits the country the Western Cape is cleaning up the damage caused from large swells, heavy rains and strong winds. Though the rough seas and the rainfall was the primary focus in the Western Cape, along the Southern Cape Coast the winds were more of a concern with extremely strong wind gusts measured. There were reports of wind gusts in excess of 50 knots in places near Port Elizabeth as the most intense front passed through the area in the middle of the week. 

In the Western Cape three various vessels almost ran around amidst the heavy seas and strong winds. While a barge, "MARGARET" ran aground near Jacobsbaai while on route from China to Rotterdam and was plans are said to be underway to salvage the barge. There were also apparently two potentially extremely dangerous, toxic chemical containers which washed up at Sea Point and Hout Bay. There were appeals for the public to stay clear of these containers for health reasons.

At least 5 mountain path closures were in place throughout the country on Thursday the 25 June as heavy snowfalls had fallen throughout Wednesday and Thursday in many of the high lying regions. Tragedy struck when a bus accident took place and left 7 people dead and over 30 injured, the accident was apparently caused by snow and ice and took place at Penhoek Pass between Jamestown and Queenstown.

The Garden Route Mall in George was also subject to tragedy but more of the financial kind as extremely strong winds ripped through the area leaving plenty of damage behind. Storm surge was also an issue as numerous coastal houses were left with minor flooding.

Currently the main system has passed and a clearance of weather can be expected in the Western Cape with temperatures into the 20s next week. But the mornings will remain cold throughout the country over the coming days and frost will almost certainly make its presence felt. Temperatures of 0`C were reported today the 26 June 2009 in Johannesburg with winds increasing the chill factor.

Should readers have any photos or information regarding events they are welcomed to send it to : This e-mail address is being protected from spambots. You need JavaScript enabled to view it  

As forecast by the South African Weather Service and as predicted by users in the forum- The Western Cape began to receive some rough weather conditions. The weather began Monday 22 June 2009 with light showers and winds beginning to increase to near 45 km/h. Though the real action occurred later into the night with the first intense band of storms arriving at around 5am to 6am on Tuesday morning. Wind gusts in excess of 30 knots were recorded and sustained winds were forecast to be near 30 knots at times during the day on Tuesday the 23 June.

The second area of storms impacted the Western Cape around 10am on Tuesday, as can be seen on the radar image below the band of storms was a squall line which had intensified off to the west of Cape Town. 

Click on Image to Enlarge

Image Credit : South African Weather Service

The squall line in question lasted for only around 15-30 minutes and was fairly fast moving, though it managed to dump plenty of rain and bring very strong wind gusts as it passed. There are traces of small branches broken and some minor flooding in Somerset West from this squall line.

Below is a webcam capture at the time the squall line was passing, showing the extremely heavy rain and strong winds- the webcam capture makes it look like a hurricane.

Image Credits : www.kapstadt.de

Looking ahead, a succession of cold fronts which are responsible for the current weather will batter the country over the next few days with snowfalls forecast on the high-grounds and heavy rains, winds and swells likely to pose a risk.

The South African Weather Service has issued the following warnings 

 
• Snowfalls are expected over the mountains Lesotho as well as the north-eastern mountains of the Eastern Cape, mainly in the morning. Snowfalls will set in over the western high ground of the Western Cape and the south-western high ground of the Northern Cape in the evening.

• Gale to strong gale force (65 to 85km/h) westerly to north- westerly winds are expected to develop between Lamberts Bay and Cape Agulhas, spreading to Port Alfred in the evening.

• Very rough seas in excess of 5m will develop between the Orange River and Port Alfred. High seas with destructive waves in excess of 7m will develop between Table Bay and Cape St. Francis in the evening.

• Heavy falls of rain (50mm or more) are expected in places over the southern parts of the West Coast District, Cape Winelands, Cape Metropole and the Overberg District of the Western Cape.

Looking Ahead

• Very cold, wet and windy conditions will persist over the high ground areas of the Western and Northern Cape on Wednesday, and will spread to the high ground of the Eastern Cape as well as the southern and eastern Free State, persisting through to Friday.

• Snowfalls will continue on Wednesday over the western high ground of the Western Cape and the southern high ground of the Northern Cape, as well as on over the mountains of Lesotho and north- eastern mountains of the Eastern Cape. Snowfalls will continue over these areas on Thursday, clearing from the west between late Thursday and Friday afternoon.

• Gale force winds (35kt/65km/h) will persist on between Lamberts Bay and Port Edward until Thursday, when moderating gradually from the west. Very rough seas with a total wave heights in excess of 5 to 7m will persist between Orange River and Port Alfred until Thursday.