mehrdad_teh
متخصص بخش هواشناسی
بله ديگه پر فشار ضعيف شده كه بادهاي سطوح 850 ميلي بار عموما جنوبي هستن و رطوبت خزر به داخل ريزش نمي كنه.
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بله ديگه پر فشار ضعيف شده كه بادهاي سطوح 850 ميلي بار عموما جنوبي هستن و رطوبت خزر به داخل ريزش نمي كنه.
دما پايينه اما براي برف خوب نيست
mehrdad_teh
متخصص بخش هواشناسی
مختصات اپي سنتر و ماه اون سال رو بگو :گل:
Amir Mohsen
متخصص بخش هواشناسی
[h=2]Ice Storm Brewing for Chicago, Detroit, St. Louis
[h=6]By Alex Sosnowski, Expert Senior Meteorologist [h=5]January 25, 2013; 10:41 AM
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Prior to the return of warmer weather, an ice storm will affect areas from northern and eastern Missouri to Michigan, southern Ontario and the mid-Atlantic spanning this weekend into the start of next week. A storm bringing rain to Southern California to end this week will roll into a zone of departing Arctic air and cold ground over the Midwest.
As AccuWeather.com Staff Writer Grace Muller alluded to on Thursday, a broad area of freezing rain and sleet is in store, lasting from a couple of hours in some locations to an entire day in others.
Major cities that have the potential for a period of freezing this weekend include Omaha, Neb.; St. Louis, Mo.; Des Moines, Iowa; Madison, Wis.; Chicago, Ill.; Indianapolis, Ind.; Detroit, Mich.; Pittsburgh, Pa.; and London, Ontario.
On the southern and western fringe of the ice/wintry mix area, the ice is likely to be brief, but even a thin coating can lead to a few hours of dangerous travel. Farther north and east, an extended period of freezing rain and sleet is possible. If mostly freezing rain occurs, widespread icy roads are likely and the risk of power outages will increase.
There is the potential for a serious ice storm from central and northern Illinois to southern Michigan with this setup. There is the potential for 0.25-0.50 of an inch of buildup of freezing rain on exposed surfaces in some locations.
According to Meteorologist Andy Mussoline, "Even in areas where the air temperature manages to get a bit above the 32-degree mark, the ground is very cold and will cause some of that rain to freeze on contact."
Freezing rain is much more dangerous than sleet.
According to Chief Meteorologist Elliot Abrams, "In many cases, the road or sidewalk appears wet, but in fact it can be covered with a thin sheen of ice, called clear ice or black ice."
"For travel and power considerations, sleet would be a better outcome than freezing rain," Abrams added.
Pockets of sleet, freezing rain and freezing drizzle are possible farther east late Sunday night into Monday morning from Buffalo, N.Y., to New York City, Philadelphia, Pa., Washington, D.C., and Roanoke, Va. In part of the Northeast, the period of ice can begin as a bit of snow.
The same problems may then advance across portions of upstate New York and New England later in the day Monday into Monday night.
The ice storm will precede a brief warmup for a several-day period next week, before arctic air makes a comeback from the northern Plains into the Midwest and Northeast during early February.
AccuWeather.com will continue to update the potential ice storm situation throughout the weekend.
More Sharing ServicesShare | Share on ******** Share on myspace Share on google Share on twitter
Prior to the return of warmer weather, an ice storm will affect areas from northern and eastern Missouri to Michigan, southern Ontario and the mid-Atlantic spanning this weekend into the start of next week. A storm bringing rain to Southern California to end this week will roll into a zone of departing Arctic air and cold ground over the Midwest.
As AccuWeather.com Staff Writer Grace Muller alluded to on Thursday, a broad area of freezing rain and sleet is in store, lasting from a couple of hours in some locations to an entire day in others.
Major cities that have the potential for a period of freezing this weekend include Omaha, Neb.; St. Louis, Mo.; Des Moines, Iowa; Madison, Wis.; Chicago, Ill.; Indianapolis, Ind.; Detroit, Mich.; Pittsburgh, Pa.; and London, Ontario.
There is the potential for a serious ice storm from central and northern Illinois to southern Michigan with this setup. There is the potential for 0.25-0.50 of an inch of buildup of freezing rain on exposed surfaces in some locations.
According to Meteorologist Andy Mussoline, "Even in areas where the air temperature manages to get a bit above the 32-degree mark, the ground is very cold and will cause some of that rain to freeze on contact."
Freezing rain is much more dangerous than sleet.
According to Chief Meteorologist Elliot Abrams, "In many cases, the road or sidewalk appears wet, but in fact it can be covered with a thin sheen of ice, called clear ice or black ice."
"For travel and power considerations, sleet would be a better outcome than freezing rain," Abrams added.
Pockets of sleet, freezing rain and freezing drizzle are possible farther east late Sunday night into Monday morning from Buffalo, N.Y., to New York City, Philadelphia, Pa., Washington, D.C., and Roanoke, Va. In part of the Northeast, the period of ice can begin as a bit of snow.
The same problems may then advance across portions of upstate New York and New England later in the day Monday into Monday night.
The ice storm will precede a brief warmup for a several-day period next week, before arctic air makes a comeback from the northern Plains into the Midwest and Northeast during early February.
AccuWeather.com will continue to update the potential ice storm situation throughout the weekend.
Amir Mohsen
متخصص بخش هواشناسی
[h=2]What is a Snow Ratio?
[h=6]By Grace Muller, AccuWeather.com Staff Writer [h=5]January 25, 2013; 6:48 AM
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Some snow is great for snowball fights while other snow won't hold its shape. Some snow is perfect for skiing while other snow just slows you down. Scientists use snow ratios to describe the different types of snow.
What are snow ratios? The snow to liquid ratio is a way of describing what makes light, fluffy snow different from heavy, wet snow. The temperature can have a huge impact on the amount of snow as well as how much it weighs. The snow ratio compares the amount of liquid precipitation with the number of inches of snow. In colder weather, snow has more air space so there are more inches of snow. Wet snow that falls at the freezing mark is usually sloppy and heavy.
Storm tracks often provide information that helps forecast the snow to water ratio. Tracks near oceans have more liquid water in clouds which usually produces lower snow-liquid ratios.
For weather enthusiasts, here's a table from the National Oceanic and Atmospheric Administration (NOAA) that gives a statistical relationship between amounts of snow that fall and the corresponding water equivalent at specified temperature ranges. The water equivalent and snowfall amounts are listed in inches. Temperature ranges are listed in degrees Fahrenheit. These values are only approximate.
More Sharing ServicesShare | Share on ******** Share on myspace Share on google Share on twitter
Some snow is great for snowball fights while other snow won't hold its shape. Some snow is perfect for skiing while other snow just slows you down. Scientists use snow ratios to describe the different types of snow.
What are snow ratios? The snow to liquid ratio is a way of describing what makes light, fluffy snow different from heavy, wet snow. The temperature can have a huge impact on the amount of snow as well as how much it weighs. The snow ratio compares the amount of liquid precipitation with the number of inches of snow. In colder weather, snow has more air space so there are more inches of snow. Wet snow that falls at the freezing mark is usually sloppy and heavy.
Storm tracks often provide information that helps forecast the snow to water ratio. Tracks near oceans have more liquid water in clouds which usually produces lower snow-liquid ratios.
For weather enthusiasts, here's a table from the National Oceanic and Atmospheric Administration (NOAA) that gives a statistical relationship between amounts of snow that fall and the corresponding water equivalent at specified temperature ranges. The water equivalent and snowfall amounts are listed in inches. Temperature ranges are listed in degrees Fahrenheit. These values are only approximate.
mohammadsadat
کاربر ويژه
ممنون لطف دارید. من عاشق اصفهانم
Amir Mohsen
متخصص بخش هواشناسی
حتما
چرا که نه
بفرمایید:
http://www.netweather.tv/
Amir Mohsen
متخصص بخش هواشناسی
ببینید این خشک سالی و کم بارشی و گرم بودن هوا تنها مختص به ایران ما نیست:
Low Snowfall Raises Concerns About Drought Recovery
By Daniel Yawitz
Follow @dyawitz
The total extent of the persistent national drought receded slightly during the past week, but in many places, conditions look no better now than they did when winter began. In particular, thin snow cover in some Western states is raising concerns that the drought’s impacts in some of the hardest-hit regions will only worsen when temperatures increase and evaporation rates rise in the spring.
Between January 15-22, the amount of land in the lower 48 states experiencing drought conditions shrank slightly, from 58.87 percent to 57.64 percent, thanks largely to precipitation that brought relief to parts of the Mid-Atlantic, Midwest and Southeast. Some of that fell in the form of snow, particularly in parts of Virginia. This marked the 31st straight week in which more than half of the continental U.S. was considered under “moderate” drought conditions or worse by the U.S. Drought Monitor.
Rainfall percentage of average during the past 180 days across the Western U.S., showing widespread below-average precipitation in most areas.
Credit: NOAA/NWS.
The drought became even more entrenched in some of the longest suffering areas, as impacts intensified slightly in Kansas, Oklahoma, and northern Texas, where thousands of square miles remain bone dry.
In the West, parts of which have seen milder-than-average temperatures and below-average snowfall since the start of the year, the low snowpack in the mountains is beginning to concern experts about whether this spring will bring enough sustained snowmelt to restore soil moisture and vegetation, and prevent a repeat of 2012’s severe wildfire season.
“The lack of snow continues to heighten concern across the West,” said Mark Svoboda of the National Drought Mitigation Center, in a news release accompanying the Drought Monitor. “While there is plenty of time to make up ground, last year’s low snowpack across the central and southern Rockies, in particular, has several interests watching closely to see if a strong finish to winter can bring about more promising streamflow forecasts for the dry season come summer,” he said.
A series of storms are forecast to roll into the Pacific Northwest in the coming week, but it’s unclear how much beneficial snow they will bring to the driest areas.
Mountain snowpack as of January 1, showing below-average snowpack in the Intermountain West and the eastern Rockies.
Credit: USDA/NRSC.
Currently, the snow cover in Colorado is sparser, and thinner than it is in an average year. Parts of the Rocky Mountains have less than half of the snow cover than they usually do at this time of year. The snow-water-equivalent in parts of the state, a measurement of how much water would be released if the snow melted, is estimated to be as low as 3.7 inches, where the median amount is 9.6 inches. The statewide average snow-water-equivalent is less than 60 percent of normal, as estimated by the SNOTEL network from the National Resources Conservation Service.
“In terms of our normal snow accumulation season, we are way behind the average,” said Nolan Doesken, a Colorado State climatologist in an interview. “We’re just a little past the midpoint of our normal snow accumulation season and there is a substantial and sufficient shortfall of snow. It would take about 150 percent of the average snow, or more, for the remainder of the winter to catch up.”
“The chances of that occurring based on the past 30 to 35 years are about 1-in-10, at best,” he said.
In a normal year, winter snow in the Rocky Mountains takes weeks to melt in the spring, and replenishes reservoirs that last the rest of the year. When that snowmelt is coupled with heavy rains in March and April, it produces an abundance of soil moisture and growth of vegetation. Part of what makes this current drought so severe was an unusual heat wave in March of 2012 that prevented that replenishing process from happening. The early warmth melted an already thin snow cover, allowed vegetation to grow too rapidly early on, and that extra demand for water helped leave the water table dry going into the summer, which is normally the time when water is scarcest.
The hot, dry weather and abundant vegetation helped set the stage for the Waldo Canyon fire, which was the largest wildfire in Colorado state history, and destroyed hundreds of homes in Colorado Springs.
Manmade global warming combined with changes in land-use practices have caused large wildfires in the West to more than double in the last few decades. Climate Central research found that in Colorado, wildfires more than 1,000 acres in size have more than quadrupled since the 1970s.
Across the West and Plains states, the drought outlook for the coming months looks grim. Last week, the National Oceanic and Atmospheric Administration released a seasonal drought outlook that forecasted the drought to persist or intensify across the West, including in Colorado.
In parts of southern Colorado, northern Texas, and Oklahoma, which have been engulfed in drought since 2011, Doesken is hoping for at least an average amount of rain, just to get them through the year.
“Anything resembling the middle of the distribution will feel wet. It won’t restore reservoirs, and it won’t restore soil moisture, but it will buy us some time and it will raise our spirits,” Doesken said, “We need a wet spring.”
Climate Central's Andrew Freedman (@afreedma) contributed to this report.
Low Snowfall Raises Concerns About Drought Recovery
- Published: January 25th, 2013
By Daniel Yawitz Follow @dyawitz
The total extent of the persistent national drought receded slightly during the past week, but in many places, conditions look no better now than they did when winter began. In particular, thin snow cover in some Western states is raising concerns that the drought’s impacts in some of the hardest-hit regions will only worsen when temperatures increase and evaporation rates rise in the spring.
Between January 15-22, the amount of land in the lower 48 states experiencing drought conditions shrank slightly, from 58.87 percent to 57.64 percent, thanks largely to precipitation that brought relief to parts of the Mid-Atlantic, Midwest and Southeast. Some of that fell in the form of snow, particularly in parts of Virginia. This marked the 31st straight week in which more than half of the continental U.S. was considered under “moderate” drought conditions or worse by the U.S. Drought Monitor.
Rainfall percentage of average during the past 180 days across the Western U.S., showing widespread below-average precipitation in most areas.Credit: NOAA/NWS.
The drought became even more entrenched in some of the longest suffering areas, as impacts intensified slightly in Kansas, Oklahoma, and northern Texas, where thousands of square miles remain bone dry.
In the West, parts of which have seen milder-than-average temperatures and below-average snowfall since the start of the year, the low snowpack in the mountains is beginning to concern experts about whether this spring will bring enough sustained snowmelt to restore soil moisture and vegetation, and prevent a repeat of 2012’s severe wildfire season.
“The lack of snow continues to heighten concern across the West,” said Mark Svoboda of the National Drought Mitigation Center, in a news release accompanying the Drought Monitor. “While there is plenty of time to make up ground, last year’s low snowpack across the central and southern Rockies, in particular, has several interests watching closely to see if a strong finish to winter can bring about more promising streamflow forecasts for the dry season come summer,” he said.
A series of storms are forecast to roll into the Pacific Northwest in the coming week, but it’s unclear how much beneficial snow they will bring to the driest areas.
Mountain snowpack as of January 1, showing below-average snowpack in the Intermountain West and the eastern Rockies.Credit: USDA/NRSC.
Currently, the snow cover in Colorado is sparser, and thinner than it is in an average year. Parts of the Rocky Mountains have less than half of the snow cover than they usually do at this time of year. The snow-water-equivalent in parts of the state, a measurement of how much water would be released if the snow melted, is estimated to be as low as 3.7 inches, where the median amount is 9.6 inches. The statewide average snow-water-equivalent is less than 60 percent of normal, as estimated by the SNOTEL network from the National Resources Conservation Service.
“In terms of our normal snow accumulation season, we are way behind the average,” said Nolan Doesken, a Colorado State climatologist in an interview. “We’re just a little past the midpoint of our normal snow accumulation season and there is a substantial and sufficient shortfall of snow. It would take about 150 percent of the average snow, or more, for the remainder of the winter to catch up.”
“The chances of that occurring based on the past 30 to 35 years are about 1-in-10, at best,” he said.
In a normal year, winter snow in the Rocky Mountains takes weeks to melt in the spring, and replenishes reservoirs that last the rest of the year. When that snowmelt is coupled with heavy rains in March and April, it produces an abundance of soil moisture and growth of vegetation. Part of what makes this current drought so severe was an unusual heat wave in March of 2012 that prevented that replenishing process from happening. The early warmth melted an already thin snow cover, allowed vegetation to grow too rapidly early on, and that extra demand for water helped leave the water table dry going into the summer, which is normally the time when water is scarcest.
The hot, dry weather and abundant vegetation helped set the stage for the Waldo Canyon fire, which was the largest wildfire in Colorado state history, and destroyed hundreds of homes in Colorado Springs.
Manmade global warming combined with changes in land-use practices have caused large wildfires in the West to more than double in the last few decades. Climate Central research found that in Colorado, wildfires more than 1,000 acres in size have more than quadrupled since the 1970s.
Across the West and Plains states, the drought outlook for the coming months looks grim. Last week, the National Oceanic and Atmospheric Administration released a seasonal drought outlook that forecasted the drought to persist or intensify across the West, including in Colorado.
In parts of southern Colorado, northern Texas, and Oklahoma, which have been engulfed in drought since 2011, Doesken is hoping for at least an average amount of rain, just to get them through the year.
“Anything resembling the middle of the distribution will feel wet. It won’t restore reservoirs, and it won’t restore soil moisture, but it will buy us some time and it will raise our spirits,” Doesken said, “We need a wet spring.”
Climate Central's Andrew Freedman (@afreedma) contributed to this report.
فروردین 56 بوده مختصات اپی سنتر (همون مختصات منطقه س؟) دقیق تمیدونم ولی مختصات شهر ما 31n ,51e هستش
Amir Mohsen
متخصص بخش هواشناسی
نقشه های جی اف اس برای روزهای 3 و 4 فوریه بارشهای سنگینی رو عمدتا به شکل برف در غالب نقاط ایران در نظر گرفته اند. :گل:
همون روز 11 فروردینه دیگه یادمه نهاوند بیش از نیم متر برف آبکی و سنگین بارید که تا پس فردا 13 بدر 90% اش آب شد یادش بخیر معجزه اقیانوس هند بود دیگه
تاج سر سروریه استقلال شما برید مرحله سوم هدفمندی بنزین و اجرا کنید
محسن جان شمال یعنی اینقدر گرمسیریه که وقتی اغلب نقاط ایران برف بیاد اونجا نمی‌آد؟
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