The recent cold wave brough gusty cool winds over the Arabian Gulf, especially off the UAE coastlines. A cold front and a low pressure developed on Jan 20 before the cold air, which caused some showers over the UAE, northern Oman, the Arabian Gulf, the Gulf of Oman, and Pakistan.

The first few days in February are expected to be rainy over the Mediterranean, KSA, and Kuwait. More updates later!

Here is the daily forecast for the UAE for Jan 20-24 which will be updated frequently.

Friday Jan 20, 2012:

Starting sunny, then becoming mostly cloudy during the day and evening hours over Qatar, Bahrain, and the UAE. chance of rain over northern UAE during the evening hours. This cloud cover is expected to enter Gulf of Oman by Saturday, where it will develop into a cold front with impact over Gulf of Oman and Pakistan. To read more about the regional weather, click here. By late Friday, cooler northwesterly winds will reach northern Arabia inlcuding Kuwait and northern KSA.

Rain Radar images of the rain showers over UAE during late hours of Friday Jan 20 and early hours of Saturday Jan 21.

Saturday Jan 21, 2012:

AM showers. Clouds to clear by mid-day, becoming windy, significantly cooler, dusty over the gulf including the UAE. Becoming very windy later during the day over the Arabian Gulf and the UAE, especially northern UAE. Very rough sea conditions. Winds in northern UAE might exceed 50 km/hr especially cities from Dubai and northward, and along the east coast as well such as Fujairah where winds descending mountains gain further speed. Much cooler across the gulf countries.

Sunday Jan 22, 2012:

Winds to subside down, but remaining breezy. Cooler weather during the day. In the UAE daytime temperatures will be in late teens, around 5 degrees below normal. Sunday night will be cold over interior areas. Due to interaction of cooler winds over relatively warmer waters of the gulf, some isolated spotty coastal shower is possible as low-level clouds cover the country.

Interaction of cooler air above relatively warmer water of the gulf caused low-level clouds that covered UAE skies on Sunday Jan 22.

Monday Jan 23, 2012:

Remaining cooler than normal. Chance of showers over the UAE coastlines of the Arabian Gulf, mainly over northern UAE. Gulf of Oman and Pakistan to receive more rain.

Tuesday Jan 24, 2012:

Clearing, becoming sunny, breezy, and remaining cooler than normal.

Synoptic weather:

After delivering rain to parts of the Mediterranean and northten Egypt, A mid-level low pressure is expected to move eastward towards southwestern Asian countries of Iran and afghanistan. With surface lows and fronts forming ahead and eastward of the upper lows, rain will fall over Iraq, Iran, then afghanistan, and Pakistan , with a cold front developing over the Gulf of Oman, northern Arabian Sea, southwestern Pakistan by Saturday Jan 21. Colder air along with a surface high will take over westward of the cold front, impacting much of the Arabian Peninsulua.

Colder Air Pushes Through:

Colder air will start making its way to the region by late Friday as windier conditions prevail , and it will be coldest in northern Arabia. Saturday and Sunday Jan 21-22 will be the coolest as daytime temperatures will fall 4-8 degrees below normal. Subsequent days will continue to be below normal, but less extreme. Kuwait and Riyadh daytime temperature on Saturday/Sunday will struggle to go above 12c with nights being quite chilly, possibly going below to -5 degrees. Bahrain and Qatar daytime temperatures will fall to mid-teens with some gusty winds on Saturday. In the UAE, daytime temperatures will be between 17-21 but with very windy conditions, and Muscat to be in early 20s.

A Lot of Winds For Some:

The Arabian Gulf will be the scene of very strong winds on Saturday with very rough sea conditions. Offshore winds will easily go beyond 60 Km/hr. UAE cities will be less extreme, but still gusty winds will blow over the northern coastlines. Winds will be between 40-50 km/hr with occasional gusts to above 50 km/hr. One area of concern is the east coast of the UAE where winds might gust beyond 60 km/hr. Open areas in northern UAE will be prone to localized dust, but coastal areas will experience fresh strong cool winds blowing from the sea. Winds will make it feel even cooler.

Unusual rain areas:

Southwest Pakistan, northern Arabian Sea, and Gulf of Oman will be under the influence of thunderstorms and rain on Saturday Jan 21.

Chance of showers for the UAE:

Small chance isolated rain showers over UAE coastlines between Saturday and Sunday. But the chance increases by Monday as a an upper air trough dives southward over the gulf, bringing some showers to northern UAE.

Clouds can be seen over upper Gulf. Jan 11, 2011.

It will generate some thundershowers while it slowly drifts southeastward and impact other Saudi Arabia cities along the Arabian Gulf coastlines. It might also bring chances of showers over Bahrain and Qatar, otherwise the front will dry up and end up bringing cooler weather on Saturday to mid sections of the Gulf before bring cooler air to the UAE on Sunday. The weather will cool siginifcantly accross KSA by Sunday and will end the recent warming. As for the warming, Jan 12-13 might bring the warmest day this winter over the Gulf countries of UAE, Bahrain, Qatar, and KSA. Many interior areas in the UAE and KSA will easily hit 30c. By Sunday, windy weather will prevail over the Arabian Gulf as cooler shamal arrives.

The upper low after moving eastward will generate wet conditions over eastern and southern Iran, afghanistan, and northern half of Pakistan.

Some showers, and some in unusual places

A few isolated thundershowers could affect parts of Saudi Arabia between late Saturday Jan 7 and early Monday Jan 9. The highest chance, although small, is over Jeddah and central parts of central Saudi Arabia that might reach Kuwait and upper parts of the Arabian Gulf. A rather unusual spot for showers will be southest coastal Pakistan and eastern Gulf of Oman on Tuesday.

Wet and Cool for the Mediterranean

A series of cold fronts and low pressures continue to impact the Mediterranean countries, especially the coastlines, with rain and some coastal thundershowers that could sometimes affect northern Egypt. This trend is expected to continue to mid January, after which cooler weather is expected to arrive, bringing temperatures down. This colder air is expected to find its way to the northern Arabian Peninsula around and after mid January.

A sunny start for Winter

Warmer for the Arabian Peninsula, cooler after mid January

Most of the Arabian Gulf countries will experience warmer than normal daytime temperatures up to Jan 12-13. Some cities will be just 1 or 2 degrees above normal such as Muscat, and others will be 5 to 7 degrees above normal such as Kuwait and Riyadh. Temperatures will be in the 20s for most of the Arabian Gulf countries. This in contrast to the fact that January is the coldest month of the year. But temperatures will quickly go from above to below normal after Jan 14, as cold air behind Mediterranean lows moves southeastward. Of course, the impact of the cold air gets eroded by the time it reaches eastern gulf such the UAE and Oman, bringing a much less intense change in temperatures, but still cooler than normal. Daytime temperatures after mid January could fall to early teens over Kuwait and Riyadh, mid teens over Bahrain, late teens over Doha, and early 20s over the UAE and Muscat. The cities that will (not) go much above normal during the next days will be the same ones that will (not) go much below normal after mid January. Somegusty winds are likely to accompany the coldwave over the Arabian Gulf.

Nov 26 – 27:

Cloudy weather will continue with isolated showers over parts of mid and eastern Arabian Gulf. Those showers might reach coastlines of Bahrain, Qatar, and western UAE.

Rain showers over Bahrain and Mid Arabian Gulf Nov 26.

Cooler weather will prevail over much of the region, bringing pleasant weather conditions.

Nov 19 – 24 Cold Front and Rain:

The subtropical high will move eastward, so will the mid-latitude low. While scatterred showers will linger over Kuwait, Iraq, and western Iran, a cold front will develop by Monday Nov 21 and will start moving eastward as well, bringing cooler air with it. While doing so, the area of scattered showers will gradually move from northen Arabian Gulf on Monday, to mid Arabian Gulf on Tuesday. This will cause scattered thunder showers over coastal Saudi Arabia, Bahrain, and then Qatar. Iraq and the mediterranean will dry up. By Tuesday the cold front will move further eastward to impact central Iran and eastern Arabian Gulf. On Wednesday some scattered showers “might” affect parts of coastal UAE and mountainous regions, northern Oman, and Gulf of Oman.

Most of the thundershowers affected UAE islands, with no noticable impact on UAE coastlines. Rainfall reached around 20mm over some UAE islands, and 44mm over Khassab in northern Oman.

Rain Radar on Wedneday Nov 23: Thunderstorms almost made it to UAE coastlines. But they still delivered rainfall to UAE islands.

Current Situation as of Nov 19:

Current temperautres accross the Arabian Gulf countries are above normal as a subtropical high pressure dominates much of the Arabian Peninsula. Meanwhile, a mid-latitude low has been affecting the eastern mediterranean with rain showers and thunderstorms. The areas of SE Iraq, Kuwait, and western Iran have been under this wedge of temperature gradient, under the oppsing air masses of the subtropical high and the mid-latitude low. With favorable surface convergence and upper divergence, clouds and scattered thundershowers have been occuring there as well over the last few days. But things are about to change.

Weather-wise, the behavior of this tropical storm was not typical. Usually, tropical storms and cyclones pass by Oman in a span of 24 hours. But Keila stalled off the Oman coast for several days, something that increases the risk of persistent rainfall, leading to floods. Keila stalled due to weak steering currents which help direct storm movement. Most of Keila’s heavy rain was offshore, and only part of it reached SE Oman (see below map). Yet it managed to pull large tropical moisture to northern Oman as well.

Arabian Sea tropical storm Keila has been dumping exceesive rain over coastal Oman. Below image from NASA TRMM site shows accumulated rain up to 9 GMT on Nov 3, 2011. We can see most coastal areas receiving around 50mm, with some areas exceeding 100mm and well into 300mm of rain over SE Oman! Some rain also reached Gulf of Oman.

7-day Accumulated rainfall ending at 9GMT on Nov 3, 2011. See the extreme rainfall over SE Oman.

These are extreme amounts and are likely to be associated with deep convective thunderstorm clouds embedded with this tropical storm. Some gusty winds have been recorded as well. With the depression lingering offshore for at least 2 more days, rainfall amounts quickly rose up, reached northeastern Oman near Muscat, but focused more around the low’s centre near SE Oman. Even as the low starts to disorganize and weaken in 72 hours, abundant left-over moisture will ensure daily scattered to isolated thunderstorms for a few more days.

Due to slight weakening of the subtropical high and slight cooling at lower levels, surface winds converging along the mountains should face less resistence to develop into isolated brief shower clouds. But October is typically a very dry month.

A period of enhanced convective precipiation is expected to start on Sunday April 10th, 2011 and continue for a few days over the Arabian Gulf, and parts of the UAE, northern Oman, Qatar, Bahrain. Convective precipiation refers to rainfall falling from towering cumulus clouds that often develop into thundershowers and even thunderstorms. Expected rainfall is likely to take on a scattered pattern, which means not all areas will receive rain.

The convective activity is expected to shift accross the highlighted area (see above image), from eastern Arabian Gulf and the UAE on some days, to mid Arabian Gulf on other days. In some days, rainfall might be favored over open waters of the Arabian Gulf, while on other days it could be land-based.

The meteorological story behind it is the existence of relatively high dew point temperatures (surface moisture of a maritime tropical air mass) along with converging and rising surface winds. Added with weak to moderate lifting from subtle vorticities advections associated with a longwave trough extending from an upper low over southeastern Europe, convective clouds are expected to form. The small-scale (mesoscale) features of convective precipiation will boil down to areas where right surface and upper-air conditions meet and result in moist convection. It will all depend on intensity and location of surface winds, temperature, dew point, in addition to convective available potential energy (CAPE), convection inhibition (CIN), upper air lifting, and vertical wind shear.

Let’s take it day by day, and determine the area favored for convective precipitation.

Sunday April 10th – Monday April 11th (AM):

• Areas prone to convective rain: Open waters of the Arabian Gulf (primary). And southwestern, northern, and central UAE (secondary).
• Again, not all areas are expected to receive rain as thundershowers will take on a scattered pattern
• T-Showers are expected to start forming during the afternoon hours of Sunday along an initiation zone of confluent surface winds over southwestern UAE extending to eastern Arabian Gulf. These are the areas where the first convective clouds are expected to form.
• After that, those convective clouds are likely to move on an easterly direction towards coastal cities of the UAE.
• Thundershowers forming over land during the day might be high-based, with less rainfall falling from them due to evaporation. However, thundershowers forming over open waters of the Gulf could contain more rainfall.
• During the evening hours of the day, thundershowers could spread more over the offshore waters of northeastern UAE and continue until the morning hours of Monday.
• I must say that although CAPE could be on the low side, high vertical wind shear between 0-6 KM above ground level could produce some long-lived thunderstorms that could potentially be strong with hail.
• If you feel a sudden cool breeze, be sure that a thundershower is nearby and watch out for the possibility of stronger winds.
• Some heavy thundershowers with high winds were reported in various parts of the UAE during the evening hours of Sunday April 10th.

Monday April 11th :

• A few scattered showers, but less widespread some scattered evening showers and maybe a few thundershowers developing over southwestern UAE during the late hours of Monday April 11, and continuing to early hours of Tuesday.
• Due to the existing cloud cover and less solar heating, convective energy (CAPE) could be less, lowering the chance of thunder activity. Thundershowers are also expected to extend to central Saudi Arabia and parts of Oman.

Tuesday April 12th:

• Reduced activity over the UAE. A few isolated showers in southern UAE and parts of Oman during early Tuesday.
• The area of convective activity shifts to mid Gulf. Late evening thundershowers and thunderstorms developing over mid Arabian Gulf, affecting Qatar, Bahrain, nearby Saudi Arabia, and western UAE.
• Chance of late night thundershowers over northeastern UAE, especially after midnight.
• But generally, the UAE remains under the area prone to showers.

Wednesday April 13th:

• AM scattered showers and a few thunderstorms over various areas of the UAE, Qatar, Bahrain, eastern Saudi Arabia, eastern and mid Arabian Gulf.
• PM: isolated showers, otherwise partly cloudy over the UAE. Risk of thundershowers continue over Qatar, Bahrain, eastern Saudi Arabia, and mid Arabian Gulf. Some may reach the UAE during late Wednesday.

Thursday April 14th:

• AM: A few showers around mid gulf, Qatar, Bahrain, eastern Saudi Arabia.
• PM: Risk of thundershowers continue over Qatar, Bahrain, eastern Saudi Arabia, and mid Arabian Gulf.

 

Friday April 15th – Sunday April 17th:

• A weak cold front with westerly winds starts arriving in the eastern Arabian Gulf.  A few rain showers (sometimes with thunder) could form over different parts of the Qatar, Bahrain, eastern Saudi Arabia, and the Arabian Gulf. Chance exists for northern UAE. Slighly cooler winds to follow.
• This is the last period of unstable day in this weather system.