Emirates Meteorology Blog

Surface lows and fronts on Fri Feb 26 2010

500 mb Low over the Middeteranian

An upper low is currently over the middeteranian countries with an occluded surface low below it have brought rain showers and thunderstorms there including some heavy showers to Egypt (and continue to do so). The occluded and warm fronts (shown in purple and red in) are causing rain and thunderstorms over parts of Iraq, Iran, NW Saudi Arabia and Kuwait. A 2nd surface low has formed over western parts of the Arabian Peninsula (near Kuwait) right below the upper air trough. Soon the occluded Low will dissipate and the new surface low will be the next weather maker.

Currently hot weather with southerly winds are affecting the UAE & Oman. It feels like summer here in the UAE with temperatures hovering in mid 30s. Right now the cold front (blue) is unable to cause any rain/thunderstorms formation due to interaction with dry air. Once it crosses the dry front (dashed black) it will interact with moist air. On Saturday/Sunday it result in thunderstorms and rain showers over many parts of the UAE (especially north) and northern Oman (Slight chance of rain in Bahrain and Qatar). Some thunderstorms could be strong due to high unstability and lifting mechanism. Rainfall amounts could be anywhere between 1 to 25 mm. Then the cold front stalls overthere (becoming stationery) and things settle down for a short time, but not for long. 

Rainfall Sat-Sun Feb 27-28, 2010

Spring starts on March 1st, 2010 with a collision between summer and winter 

The below forecast is preliminary 

Late on Monday/Tuesday , the upper low moves eastward to dive more southward sending waves of energy in the atmoshphere with high levels of unstabiltiy. As a result the cold front regenerates itself and with abundant moisture, a powerful storm system could form over the UAE and Oman (in addition to the Arabian Gulf, Gulf of Oman, and southern Iran) where strong thunderstorms and very heavy rainfall could take place. It is still unclear what areas exactly to receive the worst hit. But rainfall amounts could easily exceed 50mm in a few hours with the potential of rain exceeding 100mm under the influence of heavy thunderstorms. Anything from wadis flashflood, hailstorms, damaging thunderstorm winds is possible? Stay tuned for an update. 

Upper low moves eastward by early Wednesday

GFS Model Rainfall first late Monday early Tuesday Mar 1-2, 2010

NOGAPS Model Rainfall first late Monday early Tuesday Mar 1-2, 2010

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Recap:
There have been more than 10 death cases in Egypt due to the flood in addition to damage to properties. There have also been casualities and/or damage in Palestine, Jordan, and Saudi Arabia. There is an unconfirmed report of more than 200mm of rain falling in Sinai.

Photo of Flood in Egypt (source: storm.ae)

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This is what I like about the weather. There are no strict rules the weather has to follow. The element of surprise is always there, and there could always be extreme weather anywhere in the world. At such times, one wonders if the definition of “average weather” has any meaning at all.

Anyways, extreme weather happens when the right ingredients come at the right time and in the right place, potentially resulting in a natural disaster often in the wrong place. And this time, extreme weather has decided to pay Egypt, one of the driest places on earth, a nasty visit!

Rainfall in Egypt is mainly confined to a narrow area along north coast (i.e. Alexandria) where Middeteranian lows hardly graze the north coasts. While average rainfall along the north coast can reach 200mm per year, rainfall amount drops significantly in interior areas of Egypt, where Cairo hardly received 10mm of rain per year, if nothing at all, due to very dry desert air, which makes all cold fronts very dry ones. South of Cairo, only a trace of rain is recorded, or in most cases no rain at all. Some areas can experience no rain for several years.

Egypt-map

But tomorrow (Sunday Jan 17, 2010), a deep upper low that will dive more southward than normal, drawing with it lots of equatorial moisture, and mixing it with cold air aloft, will result in a wide area of extreme rainfall and strong thunderstorms in the eastern half of the interior region of Egypt. Many areas could exceed 50mm of rain within the span of 24 hours only (if not less than 12 hours). And should strong thunderstorms hit, there could be as much as 100mm or 150mm in those areas. With such a very unstable atmosphere, it is hard to pinpoint exaclty where extreme rainfall will hit, but the NE quadrant of Egypt from all the way from the north coast to the mid interior areas of Egypt could experience very heavy rain. But the mountaineous areas of Egypt should really watch out for runoffs and flash floods. I can’t imagine what exactly will happen in an area that hardly receives 10 mm or no rain per year.

500mb heights Moday 00:00 GMT Jan 17, 2010

Rainfall on Sunday Jan 17, 2010

Rain and thunderstorms will also spread quickly to other countries … Continue reading Powerful Thunderstorms and Rain to Hit Egypt Jan 17 and 18, 2010 »»»

A very powerful low pressure weather system is going to impact eastern Egypt (Sinai expecially), Lebanon, Syria, Jordan, Palestine and NW Saudi Arabia. There might be severe thunderstorms in Sinai, NW Saudi Arabia,  and very heavy rain in the Middeteranian countries. All of that will happen on Sunday and Monday.

24-hour forecasted rainfall between 12 GMT Sunday to 12 GMT Monday. Notice the extreme rainfall.

Later more low pressure systems to continue impacting Lebanon, Palestine, Syria, and Jordan until Jan 20 (possibly) with rain accumulation reaching 200mm along the coastal areas (but no impact on NW Saudi Arabia).

I would say the mountaineous areas on NW Saudi Arabia and Sinai areas in Egypt should consider the possibility of flash flood.