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درود ایرج ، اینجا هوا تاریک شده احتمالا بارش در پیش داریم ، راستی سیستم آخر هفته هم در ECMWF پنجشنبه و جمعه هست در صورتیکه در GFS یکشنبه ، دوشنبه ، خدا بخواد سه شنبه میرم فریدونشهر و با عکسای برفی بر میگردم
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- شروع کننده موضوع Amir Mohsen
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درود ایرج ، اینجا هوا تاریک شده احتمالا بارش در پیش داریم ، راستی سیستم آخر هفته هم در ECMWF پنجشنبه و جمعه هست در صورتیکه در GFS یکشنبه ، دوشنبه ، خدا بخواد سه شنبه میرم فریدونشهر و با عکسای برفی بر میگردم
حامد از اصفهان
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نظر منم اینه محسن جان
به احتمال زیاد آپ بعدی بارشاهارو تو روزهای بیشتری تقسیم میکنه
یعنی از سیستم اخر هفته بارش نداریم.
حامد از اصفهان
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حامد از اصفهان
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بارش باران بعد از یک ماه هم اکنون
درود امیر جان
آره واقعا ناقص بوده نه به 56 م م دیشبش نه به 5 م م امروزش
اینجاهم تاریکه ولی تا الان خبری نبوده ،منتظر عکسات هستم با دست پر برگرد
Amir Mohsen
متخصص بخش هواشناسی
Ferocious Storm Set to Explode in North Atlantic
By Andrew Freedman
Follow @afreedma
Some of the most powerful storms on earth form in the North Atlantic Ocean during wintertime, spelling peril for sailors unfortunate enough to encounter them. For the past few days, the meteorologists at the Ocean Prediction Center (OPC) in College Park, Md., whose job it is to warn vessels of weather hazards, have been highlighting the likelihood of a treacherous storm event that is about to take place in the open ocean, to the south of Iceland.
The storm (circled) prior to its rapid intensification, as modeled by the ECMWF computer model.
Click to enlarge the image. Credit: Weatherbell.com.
What is currently a relatively innocuous weather system spreading light snow, freezing rain, and rain across the eastern U.S. is forecast to explode, through a process known to meteorologists as “bombogenesis,” into a ferocious storm once it emerges over the North Atlantic. Computer models indicate that the storm may intensify so significantly that it will have a minimum central pressure that is lower than what was recorded during Hurricane Sandy. That storm devastated the northern Mid-Atlantic coast in late October and the lowest pressure recorded during it was 940 millibars (mb).
In a ******** post on Friday, the OPC said the storm is expected to undergo “incredible, explosive cyclogenesis” during the next 24 hours, with the central pressure plummeting from 988 mb on Friday down to 927 mb by late Sunday. (In general, the lower the central air pressure, the stronger the storm.)
The storm (circled) after undergoing a rapid intensification process, with a modeled central pressure of 927 mb.
Click to enlarge the image. Credit: Weatherbell.com.
At its maximum intensity, the storm will be capable of producing winds to 90 mph, and waves of greater than 50 feet, the OPC said.
Fortunately, the storm is expected to weaken considerably before it interacts with northwestern Europe, but it could still produce strong winds in Ireland and parts of the U.K.
The storm comes about 10 days after a different storm underwent a similar process of rapid intensification over the North Pacific Ocean, pummeling the western Aleutian Islands of Alaska with hurricane force winds and high waves, but sparing the rest of the state from any major impacts.
Computer model forecast for early Sunday of significant wave heights over the N. Atlantic. (Some waves will actually be higher than indicated here, since this shows the average of the top one-third of waves.)
Credit: ********/Stu Ostro.
The North Pacific storm's minimum central pressure plunged by 48 to 49 mb in just 24 hours, making it one of the most rapidly intensifying storms at a mean latitude of 34°N since 1979, according to a data analysis by Ryan Maue of Weatherbell Analytics..
As strong as the upcoming Atlantic storm is expected to get, it is not likely to set any records. The strongest extratropical storm on record in the North Atlantic occurred in 1993, when a minimum central pressure of 913 mb was recorded near Scotland’s Shetland Islands, according to Weather Underground. That was the lowest sea-level adjusted barometric pressure reading observed on the earth’s surface, with the exception of lower readings measured during tropical cyclones and tornadoes.
Climate studies have shown that extratropical storms in the Northern Hemisphere are shifting their paths northward as the climate warms, and there has been a trend toward stronger Arctic storms in recent years. However, the question of whether characteristics of storms like the one this weekend are changing in response to the warming climate is unclear, given the fact that these events have a long history in the region.
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- Published: January 25th, 2013, Last Updated: January 25th, 2013
By Andrew FreedmanFollow @afreedma
Some of the most powerful storms on earth form in the North Atlantic Ocean during wintertime, spelling peril for sailors unfortunate enough to encounter them. For the past few days, the meteorologists at the Ocean Prediction Center (OPC) in College Park, Md., whose job it is to warn vessels of weather hazards, have been highlighting the likelihood of a treacherous storm event that is about to take place in the open ocean, to the south of Iceland.
The storm (circled) prior to its rapid intensification, as modeled by the ECMWF computer model.Click to enlarge the image. Credit: Weatherbell.com.
What is currently a relatively innocuous weather system spreading light snow, freezing rain, and rain across the eastern U.S. is forecast to explode, through a process known to meteorologists as “bombogenesis,” into a ferocious storm once it emerges over the North Atlantic. Computer models indicate that the storm may intensify so significantly that it will have a minimum central pressure that is lower than what was recorded during Hurricane Sandy. That storm devastated the northern Mid-Atlantic coast in late October and the lowest pressure recorded during it was 940 millibars (mb).
In a ******** post on Friday, the OPC said the storm is expected to undergo “incredible, explosive cyclogenesis” during the next 24 hours, with the central pressure plummeting from 988 mb on Friday down to 927 mb by late Sunday. (In general, the lower the central air pressure, the stronger the storm.)
The storm (circled) after undergoing a rapid intensification process, with a modeled central pressure of 927 mb.Click to enlarge the image. Credit: Weatherbell.com.
At its maximum intensity, the storm will be capable of producing winds to 90 mph, and waves of greater than 50 feet, the OPC said.
Fortunately, the storm is expected to weaken considerably before it interacts with northwestern Europe, but it could still produce strong winds in Ireland and parts of the U.K.
The storm comes about 10 days after a different storm underwent a similar process of rapid intensification over the North Pacific Ocean, pummeling the western Aleutian Islands of Alaska with hurricane force winds and high waves, but sparing the rest of the state from any major impacts.
Credit: ********/Stu Ostro.
The North Pacific storm's minimum central pressure plunged by 48 to 49 mb in just 24 hours, making it one of the most rapidly intensifying storms at a mean latitude of 34°N since 1979, according to a data analysis by Ryan Maue of Weatherbell Analytics..
As strong as the upcoming Atlantic storm is expected to get, it is not likely to set any records. The strongest extratropical storm on record in the North Atlantic occurred in 1993, when a minimum central pressure of 913 mb was recorded near Scotland’s Shetland Islands, according to Weather Underground. That was the lowest sea-level adjusted barometric pressure reading observed on the earth’s surface, with the exception of lower readings measured during tropical cyclones and tornadoes.
Climate studies have shown that extratropical storms in the Northern Hemisphere are shifting their paths northward as the climate warms, and there has been a trend toward stronger Arctic storms in recent years. However, the question of whether characteristics of storms like the one this weekend are changing in response to the warming climate is unclear, given the fact that these events have a long history in the region.
Related Content
Stratospheric Phenomenon Is Bringing Frigid Cold to U.S.
Monster Storm Lashing Outer Reaches of Alaska
Ongoing Coverage of Hurricane Sandy
Alaska Superstorm Lashes Villages Already Hit Hard By Climate Change
آخرین ویرایش:
Amir Mohsen
متخصص بخش هواشناسی
[h=2]Evolution of the Arctic Outbreak
[h=6]By Alex Sosnowski, Expert Senior Meteorologist[h=5]January 25, 2013; 10:00 PM
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Around the start of 2013, meteorologists at AccuWeather.com noticed that a change in temperature high the atmosphere over the North Pole was occurring and projected an arctic outbreak in North America during the middle of January.
The phenomenon is known as sudden stratospheric warming.The explanation is a little complex, but we will try to bring it to layman's terms. Just keep in mind there are also other players on the field, which we do not mention.If you view the stratosphere as a mirror image or an opposite of the part of the atmosphere where we live and breathe (the troposphere), it may be easier to understand.On Dec. 28, 2012, Expert Senior Meteorologist Brett Anderson, who monitors the stratosphere for changes, noticed that one of his forecasting tools was projecting sudden warming of the stratosphere during the first week of January.
The phenomenon is known as sudden stratospheric warming.The explanation is a little complex, but we will try to bring it to layman's terms. Just keep in mind there are also other players on the field, which we do not mention.If you view the stratosphere as a mirror image or an opposite of the part of the atmosphere where we live and breathe (the troposphere), it may be easier to understand.On Dec. 28, 2012, Expert Senior Meteorologist Brett Anderson, who monitors the stratosphere for changes, noticed that one of his forecasting tools was projecting sudden warming of the stratosphere during the first week of January.
While the air gets colder with increasing height in the troposphere, the temperature gradually increases with height in the stratosphere. However, while big temperature swings occur frequently near the ground, once in a while they also occur in the stratosphere as well.During the first few days of January 2013, the stratospheric warming event was confirmed by Meteorologist Mark Paquette."While all of the causes of the event are still not known, the chain reaction that occurs following the sudden warming in the stratosphere typically leads to one or more arctic outbreaks at the mid-latitudes around the Northern Hemisphere roughly two to three weeks later," Paquette said.One theory as to the cause of the warming is the destruction of ozone during the late fall and early winter."Ozone needs sunlight to form and a lack of sunlight leads to its demise. When the ozone is depleted, it may contribute to stratospheric warming," according to Paquette.The problem with the theory is that it explains the gradual warming of the stratosphere from fall into winter, but not the sudden warmups that can occur a couple of times during the cold weather season."Something holds back the warming and then it breaks, like a rubber band snapping." Paquette added.Another theory is that large storms in the lower part of the atmosphere (the troposphere) cause perturbations in the stratosphere and may allow the upper atmosphere to warm suddenly.When the stratosphere suddenly warms, it forces a large area of low pressure at the surface, known as the polar vortex, to weaken.
This image of the upper atmosphere shows the polar vortex situated near the North Pole on Dec. 15, 2012. (Image appears courtesy of the University of Wyoming.According to Chief Meteorologist Elliot Abrams, "With the vortex no longer strong enough to contain the frigid surface air near the pole, the dam breaks and allows the cold air to start moving southward."This occurred during the middle of January. It allowed some cold air to seep southward over the Canada Prairies, into the western U.S. for several days and intermittently into the northern Plains and northern New England. However, it was not the main thrust of arctic air.Sometimes the vortex itself breaks into multiple parts and moves southward.
This image of the upper atmosphere shows the polar vortex split in two on Jan. 10, 2013. One center was over the Northwest Territories the other was over eastern Russia. (Image appears courtesy of the University of Wyoming.)This was the case during week three to week four of January. The polar vortex, essentially the meteorological North Pole, shifted its position to northern Quebec, Canada.In Europe and Asia, the other piece of the vortex was displaced southward setting up a wedge of cold air, displacing steering-levels winds and setting up cold storms from the United Kingdom to part of the Middle East.With the North America polar vortex positioned over northern Quebec, the cold air engine was running at three-quarters throttle.
A counterclockwise flow around the giant system directed frigid air near the ground southward across the Canada Prairies and into the northern Plains and Northeastern U.S. creating the outbreak.Only a larger vortex farther south would result in a full throttle widespread wave of frigid air from the northern Plains and New England southward to Texas and Florida.According to Expert Senior Meteorologist Dave Dombek, "This occurred during the super Arctic outbreaks in December of 1983 and 1989, as well as in January 1985 and 1994."This did not happen this time, nor does it look like it will happen this winter.According to Paul Pastelok, head of AccuWeather.com's Long Range Forecasting Department, "Indications are the vortex will fluctuate in intensity and position but will remain in the overall general area into February."This means more waves of frigid air, or arctic outbreaks, can be expected into roughly the same locations of North America."It is possible, however, that as the vortex wobbles around, than one or more episodes of rugged cold will visit parts of the West over the next couple of weeks and the cold may take another break in the East," Pastelok said.The shifting waves of cold and warmth could play havoc on aging water line systems from the Midwest to the Northeast."Over the years I have have noticed a surge in water line breaks after a recent arctic outbreak is followed by a warmup," Abrams stated.The cold waves will likely lead to higher energy consumption, and potentially higher heating bills, when compared to last winter has a whole for people from the northern Plains to the
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