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Saturday, February 18, 2012
Gulf Stream
Surface temperature in the western NorthAtlantic. North America is black and dark blue (cold), the Gulf Stream red (warm). Source: NASA
The Gulf Stream, together with its northern extension towards Europe, the North Atlantic Drift, is a powerful, warm, and swift Atlantic ocean current that originates at the tip of Florida, and follows the eastern coastlines of the United States and Newfoundland before crossing the Atlantic Ocean. The process of western intensification causes the Gulf Stream to be a northward accelerating current off the east coast of North America. At about 40°0′N 30°0′W, it splits in two, with the northern stream crossing to northern Europe and the southern stream recirculating off West Africa. The Gulf Stream influences the climate of the east coast of North America from Florida to Newfoundland, and the west coast of Europe. Although there has been recent debate, there is consensus that the climate of Western Europe and Northern Europe is warmer than it would otherwise be due to the North Atlantic drift, one of the branches from the tail of the Gulf Stream. It is part of the North Atlantic Gyre. Its presence has led to the development of strong cyclones of all types, both within the atmosphere and within the ocean. The Gulf Stream is also a significant potential source of
renewable power generation.
renewable power generation.
History
Benjamin Franklin's map of the Gulf Stream
European discovery of the Gulf Stream dates to the 1513 expedition of Juan Ponce de León, after which it became widely used by Spanish ships sailing from the Caribbean to Spain.[1]
A summary of Ponce de León's voyage log, on April 22, 1513, noted, "A
current such that, although they had great wind, they could not proceed
forward, but backward and it seems that they were proceeding well; at
the end it was known that the current was more powerful than the wind."[2] Its existence was also known to Peter Martyr d'Anghiera, and to Sir Humphrey Gilbert at that time.[3]
As deputy postmaster of the British American colonies, Benjamin Franklin became interested in the North Atlantic Ocean
circulation patterns. In 1768, while in England, Franklin heard a
curious complaint from the Colonial Board of Customs: why did it take
British packets several weeks longer to reach New York from England than it took an average American merchant ship to reach Newport, Rhode Island, despite the merchant ships leaving from London and having to sail down the River Thames and then the length of the English Channel before they sailed across the Atlantic, while the packets left from Falmouth in Cornwall?[4]
Franklin asked his cousin Timothy Folger, a Nantucket whaling
captain, for an answer and Folger explained that merchant ships
routinely crossed the then-unnamed Gulf Stream – identifying it by whale
behavior, measurement of the water's temperature and the speed of
bubbles on its surface, and changes in the water's color – while the
mail packet captains ran against it.[4]
Franklin worked with Folger and other experienced ship captains,
learning enough to chart the Gulf Stream and giving it the name by which
it is still known today. He offered this information to Anthony Todd,
secretary of the British Post Office, but it was ignored by British sea
captains.[4]
Franklin's Gulf Stream chart was published in 1770 in England, where it was mostly ignored.[5] Subsequent versions were printed in France in 1778 and the U.S. in 1786.[6]
It took many years for the British to follow Franklin's advice on
navigating the current but once they did, they were able to gain two
weeks in sailing
time.[6]
time.[6]
Properties
The Gulf Stream proper is a western-intensified current, driven largely by wind stress.[7] The North Atlantic Drift, in contrast, is largely thermohaline circulation-driven. By carrying warm water northeast across the Atlantic, it makes Western and especially Northern Europe warmer than it otherwise would be.[8]
However, the extent of its contribution to the actual temperature
differential between North America and Europe is a matter of dispute as
there is a recent minority opinion within the science community that
this temperature difference is mainly due to the Atlantic Ocean being
upwind of western Europe (producing an oceanic climate) and a landmass being upwind of the east coast of North America.[9]
Formation and behavior
Evolution of the Gulf Stream to the west of Ireland continuing as the North Atlantic Current
A river of sea water, called the Atlantic North Equatorial Current, flows westward off the coast of northern Africa. When this current interacts with the northeastern coast of South America, the current forks into two branches. One passes into the Caribbean Sea, while a second, the Antilles Current, flows north and east of the West Indies.[10] These two branches rejoin north of the Straits of Florida, as shown on the accompanying map.
The trade winds blow westward in the tropics,[11] and the westerlies blow eastward at mid-latitudes.[12] This wind pattern applies a stress to the subtropical ocean surface with negative curl across the north Atlantic ocean.[13] The resulting Sverdrup transport is equatorward.[14] Because of conservation of potential vorticity caused by the northward-moving winds on the subtropical ridge's
western periphery and the increased relative vorticity of northward
moving water, transport is balanced by a narrow, accelerating poleward
current, which flows along the western boundary of the ocean basin,
outweighing the effects of friction with the western boundary current
known as the Labrador current.[15]
The conservation of potential vorticity also causes bends along the
Gulf Stream, which occasionally break off due to a shift in the Gulf
Stream's position, forming separate warm and cold eddies.[16]
This overall process, known as western intensification, causes currents
on the western boundary of an ocean basin, such as the Gulf Stream, to
be stronger than those on the eastern boundary.[17]
As a consequence, the resulting Gulf Stream is a strong ocean
current. It transports water at a rate of 30 million cubic metres per
second (30 sverdrups) through the Florida Straits. As it passes south of Newfoundland, this rate increases to 150 million cubic metres per second.[18]
The volume of the Gulf Stream dwarfs all rivers that empty into the
Atlantic combined, which barely total 0.6 million cubic metres per
second. It is weaker, however, than the Antarctic Circumpolar Current.[19]
The Gulf Stream is typically 100 kilometres (62 mi) wide and 800
metres (2,600 ft) to 1,200 metres (3,900 ft) deep. The current velocity
is fastest near the surface, with the maximum speed typically about 2.5
metres per second (5.6 mph).[20] As it travels north, the warm water
transported by the Gulf Stream undergoes evaporative cooling. The
cooling is wind-driven: Wind moving over the water cools it and also
causes evaporation, leaving a saltier brine. In this process, the water increases in salinity
and density, and decreases in temperature. Once sea ice forms, salts
are left out of the ice, a process known as brine exclusion.[21]
These two processes produce water that is denser and colder (or, more
precisely, water that is still liquid at a lower temperature). In the
North Atlantic Ocean, the water becomes so dense that it begins to sink down through less salty and less dense water. (The convective action is not unlike that of a lava lamp.) This downdraft of heavy, cold and dense water becomes a part of the North Atlantic Deep Water, a southgoing stream.[22] Very little seaweed lies within the current, although seaweed lies in clusters to its east.[23]
Localized effects
The Gulf Stream is influential on the climate of the Florida
peninsula. The portion off the Florida coast, referred to as the Florida
current, maintains an average water temperature at or above 25 °C (77 °F) during the winter.[24] East winds moving over this warm water move warm air from over the Gulf Stream inland,[25]
helping to keep temperatures milder across the state than elsewhere
across the Southeast during the winter. The Gulf Stream's proximity to Nantucket adds to its biodiversity, as it is the northern limit for southern varieties of plant life, and the southern limit for northern plant species.[26]
The North Atlantic Current of the Gulf Stream, along with similar warm air currents, helps keep Ireland and the western coast of Great Britain a couple of degrees warmer than the east.[27] However, the difference is most dramatic in the western coastal islands of Scotland.[28]
A noticeable effect of the Gulf Stream and the strong westerly winds
(driven by the warm water of the Gulf Stream) on Europe occurs along the
Norwegian coast.[8] Northern parts of Norway lie close to the Arctic
zone, most of which is covered with ice and snow in winter. However,
almost all of Norway's coast remains free of ice and snow throughout the
year.[29] Weather systems warmed by the Gulf Stream drift into Northern Europe, also warming the climate behind the Scandinavian mountains.
Effect on cyclone formation
The warm water and temperature contrast along the edge of the Gulf Stream often increase the intensity of cyclones, tropical or otherwise. Tropical cyclone generation normally requires water temperatures in excess of 26.5 °C (79.7 °F).[30]
Tropical cyclone formation is common over the Gulf Stream, especially
in the month of July. Storms travel westward through the Caribbean and
then either move in a northward direction and curve toward the eastern
coast of the United States or stay on a north-westward track and enter the Gulf of Mexico.[31] Such storms have the potential to create strong winds and extensive damage to the United States' Southeast Coastal Areas. Strong extratropical cyclones have been shown to deepen significantly along a shallow frontal zone, forced by the Gulf Stream itself during the cold season.[32] Subtropical cyclones
also tend to generate near the Gulf Stream. 75 percent of such systems
documented between 1951 and 2000 formed near this warm water current,
with two annual peaks of activity occurring during the months of May and
October.[33]
Cyclones within the ocean form under the Gulf Stream, extending as deep
as 3,500 metres (11,500 ft) beneath the ocean's surface.[34]
Possible renewable power source
The Gulf Stream transports about 1.4 petawatts of heat, equivalent to 100 times the world energy demand,[35]
and research into different ways to tap this power is being undertaken.
One idea, which would supply the equivalent power of several nuclear
power plants, would deploy a field of underwater turbines placed 300
meters (980 ft) under the center of the core of the Gulf Stream, such as
being developed by Aquantis, LLC.[36]
Ocean thermal energy could also be harnessed to produce electricity
utilizing the
temperature difference between cold deep water and warm surface water.[37]
http://en.wikipedia.org/wiki/Gulf_Stream
temperature difference between cold deep water and warm surface water.[37]
http://en.wikipedia.org/wiki/Gulf_Stream
Snow, Rain Showers Swing through Northeast
Feb 18, 2012; 4:05 PM ET
A weak storm is pushing through the Northeast this evening with spotty snow and rain showers.
The system is not associated with the storm brewing in the South.
The snow showers can produce a quick coating of snow to some grassy and elevated surfaces in part of central and southern New England, upstate New York, northern Pennsylvania and northwestern New Jersey.
The snow will melt on most road surfaces.
Rain showers or a mix of rain and wet snow showers are in store for the coastal areas including New York City, Providence, Boston and Philadelphia this evening.
During Friday night, the storm managed to bring a few inches of snow to parts of Michigan.
A push of dry air and building high pressure in the wake of this disturbance on Sunday will work to keep the southern storm and its snow generally south of the Mason-Dixon Line.
Washington, D.C. and Baltimore will be on the northern fringe of the snowstorm.
Farther to the northeast, a snowstorm will clobber Newfoundland.
Another Atlantic Canada Weekend Snowstorm
Feb 18, 2012; 3:40 PM ET
As the mid-Atlantic of the United States prepares for a snowstorm this weekend, a storm will hit part of Atlantic Canada with heavy snow for the second weekend in a row.
The storm will generally put down heavier snow a bit farther east compared to last weekend's event, particularly over Newfoundland.
The storm will come into full bloom tonight into Sunday. While a great deal of the snow will fall over the Gulf of St. Lawrence, up to 30 centimeters of snow will fall on western Newfoundland, much of Cape Breton Island and part of the eastern arm of Quebec.
Snow is taking aim at Newfoundland and the Gulf of St. Lawrence region this weekend. (Kirk Gisler/Photos.com)
Snow will fall over part of New Brunswick and Nova Scotia into this evening, before the storm gels farther to the northeast.
While this storm will bring some wind, it will not be as intense as
the storm a week ago. However, enough snow and wind will occur to create
difficult travel. Overall, it will be a colder storm with little or no
rain for eastern areas.
It is interesting that it is this storm and part of the blocking
pattern it creates that will prevent a separate storm from the southern
U.S. from reaching New England late in the weekend.
Climate Change | Episodes of Extreme Summertime Heat becoming more Common
Feb 17, 2012; 10:35 AM ET
Assuming it will remain business as usual in terms of greenhouse gas emissions, episodes of extreme summertime heat will actually be the norm by mid-century in the Lower 48 states, according to new research from the Lawrence Livermore National Laboratory.
The research team compared temperature data from 1975-2000 with similar data from 1950-1974 and determined that these observations along with results from running 16 climate models shows that episodes of extreme summertime heat that was once rare will occur in more than 50% of summers by mid-century across the Lower 48 states.
Perhaps a future population and real estate boom for Alaska or Atlantic Canada??? Just a thought.
The team also performed a statistical analysis showing that the increase in rare summertime temperatures seen from 1975-2000 are very unlikely to have occurred through chance weather variations, such as El Nino or La Nina.
By mid-century, extreme summertime temperatures are are expected to occur in at least 70% of the summers in the lower 48, compared to the historical average that is closer to 5%.
Excerpt from the LLNL news release.........
"The observed increase in the frequency of previously rare summertime-average temperatures is more consistent with the consequences of increasing greenhouse gas concentrations than with the effects of natural climate variability," said LLNL's Phil Duffy, who is the lead author of a report in a recent edition of the journal, Climatic Change. "It is extremely unlikely that the observed increase has happened through chance alone."
Saturday snowfall blankets parts of Ontario
. February 18, 2012 — A light dusting of snow fell in parts of Ontario on Saturday
People in Ontario woke up to a fresh coat of snow of snow on
Saturday, courtesy of a weak low pressure system that swept across the
area beginning Friday night.
In many areas, the snowfall has been light: Toronto has seen 5 cm so far and Hamilton has seen slightly less, at 3 cm.
But over in Barrie, the conditions appear to be changing by the hour.
Mark Rozitis, a camera operator for the Weather Network, has been monitoing the situation in and around the area.
"The snow is coming down heavy and it has been all morning," he said. "There's more than 10 cm on the ground already, [and] while that's great for the hundreds heading up to ski country, the roads are extremely slippery ... and we have lots of accidents and cars sliding out," he said, adding that the snow is "some of the slipperiest" he has ever driven on
Several accidents have been reported on Highway 400, bringing traffic to a crawl in some places.
Earlier this week, icy road conditions led to bus cancellations and car accidents in the southwestern part of the province.
Hitting the slopes this weekend? Be sure to check our Ski report. If you're going to be in the city of Ottawa, read more about the final weekend of Winterlude.
.
Damaging Gulf Coast Storm Threat into Tonight
Feb 18, 2012; 10:45 AM ET
As a developing storm system moves along, severe thunderstorms with damaging winds and the potential for tornadoes will push eastward along the Gulf Coast.
While flash and urban flooding remains the primary threat
for travelers and residents in the I-10 and I-20 corridors of the South
into tonight, there is also a substantial risk for damaging winds,
including a few tornadoes near the Gulf Coast.
The storms have had a history of flash flooding and damaging wind
gusts in Texas and western Louisiana this morning. There have been
reports of funnel clouds.
The building warmth and Gulf moisture will make the atmosphere increasingly volatile this afternoon and evening.
A developing warm sector from southeastern Louisiana to the Florida
Panhandle is the area to watch this afternoon and evening for possible
tornadoes. This threat area extends from New Orleans to Biloxi, Miss.,
to Mobile, Ala., to Tallahassee, Fla., as forewarned by Meteorologist Meghan Evans.
There is also a risk of a couple of tornadoes occurring farther
inland, among clusters of thunderstorms. These storms could be wrapped
in heavy rainfall and concealed from view.
Thunderstorms with damaging wind gusts, perhaps topping 70 mph have
the potential to bring downed trees, blocked roadways and neighborhood
power outages.
The risk of violent thunderstorms and and tornadoes will extend
through the night along the northeastern Gulf Coast and reaching into
southern Georgia and southern Alabama. The potential for a few night
time tornadoes will add to the danger, since some people may not realize
such a storm is coming.
The risk of damaging thunderstorms will continue into Sunday and will
stretch from the northern counties of the Florida Peninsula to perhaps
as far north as the coastal areas of North Carolina.
People are urged to keep a close eye on the weather situation and be prepared to seek shelter as storms approach.
Flooding Rain Texas to Georgia This Weekend
Feb 18, 2012; 7:43 AM ET
A developing storm system set to ignite severe weather across the central Gulf Coast today and a significant snowstorm over the mid-Atlantic on Sunday is producing torrential rain over the Lone Star State this morning.
About 1 to 2 inches of rain has already fallen over several locations in Texas within the past 12 hours. Moreover, Houston, Orange and Waco all have received rainfall above of the 2-inch mark.
The torrential rainfall has also caused areas of flash flooding across central and northeastern Texas. High water has forced law enforcement and emergency management officials to close roads in around Austin.
Enough rain will fall with the storm system this weekend to cause urban flooding problems.
Residents in New Orleans, La., Mobile, Ala. and Tallahassee, Fla. and
other cities and communities should be prepared for rapidly changing
weather conditions and should heed any severe storm or flash flood
related warnings.
The primary threats with these storms will be blinding downpours and strong, potentially damaging wind gusts.
Extremely heavy rain that falls in a very short time period is
capable of producing additional flash flooding from the I-10 to the I-20
corridor and will reach at least as far north as Jackson, Miss.,
Birmingham, Ala., Atlanta, Ga. and Columbia, S.C.
Low lying and poor drainage areas are especially at risk.
A general 2- to 4 inches of rain is expected over much of the Deep
South through Sunday morning. A few locations can receive up to 6 inches
of rain.
Flash flooding is extremely dangerous and should not be taken
lightly. A foot of fast-moving water is capable of sweeping away cars
and other large objects.
If you find yourself driving towards a water-covered roadway, turn
around and find an alternative route. Do not put yourself and rescuers
at risk.
Despite the flash flooding and the threat for severe thunderstorms
this morning, the rain that falls will continue to help improve the
ongoing exceptional drought that grips much of the state.
A large storm system will continue to press eastward today, setting
the stage for additional heavy rain and even strong-to-severe
thunderstorms along the coast of the Gulf of Mexico.
Ample moisture from the Gulf of Mexico and a fast-moving jet stream
higher up in the atmosphere are providing the necessary ingredients for a
significant heavy rain event today into tonight.
Sunday Snow Kentucky, Virginias and North Carolina
Feb 18, 2012; 8:39 AM ET
A snowstorm will take shape over the mountains of Virginia and West Virginia late tonight and will expand across Kentucky into northern Tennessee, northwestern North Carolina, and eastward across Virginia on Sunday into Sunday evening.
As colder air invades the storm on Sunday afternoon and Sunday evening, rain will change to snow in lower elevations in these areas.
Cities in the path of an upcoming expanding area of snow will include Beckley, W.Va., Charlottesville, Va. and London, Ky.
Some kids may have a blast playing in the snow in the wake of the storm on Monday. (Photos.com photo)
A general 3 to 6 inches of snow is expected in this zone with locally
higher amounts, especially in the highest elevations, where a foot is
possible.
Snow is also forecast to reach places usually too warm for snow including Charlotte, N.C., Richmond, Va. and Nashville, Tenn.
In order to get snow to accumulate on roads during the day, it must
snow hard. However, this is possible in part of the central
Appalachians. Travel in part of the I-75, I-77 and I-81 corridors could
get rough for a while.
During the late afternoon and nighttime hours, as temperatures drop
slightly and the sun's effect is lost, look for roads to turn slushy and
snowcovered. Slippery conditions can even spread into the I-95 corridor
in Virginia on Sunday night.
Dry air will hold its ground over Indiana, Ohio, Pennsylvania, New
York and New Jersey, and will create a rather sharp northern edge to the
accumulating snow.
No snow is expected from this storm in New York City, Philadelphia, Pittsburgh, Columbus, Ohio and Indianapolis.
A matter of a dozen miles may well determine which areas are completely dry, versus a couple of inches of snow.
The northern edge will run east-west just south of the Ohio River to
the northern Delmarva. It appears most of the accumulating snow will
slip just south of Washington, D.C. and Baltimore, Md.
Like many storms, this storm will have many faces. In the South,
severe weather is unfolding ranging from flash flooding to damaging
thunderstorms and tornadoes.
A good side to the storm will be a late-season Presidents Day boost
for skiing in parts of the central and southern Appalachians as well as a
good swift kick into the building drought from Florida to coastal North
Carolina.
Some kids (and adults) who have Monday off for the holiday or because
of weather conditions will be able to finally get out and play in the
snow.
Snow may linger for a time in portions of the Delmarva, Virginia and
North Carolina to start on Monday, but sunshine should return to most
areas as the day progresses.
Friday, February 17, 2012
AccuWeather.com - Elliot Abrams | Snow Sunday for Parts of Middle Atlantic States
Snow Sunday for Parts of Middle Atlantic States
Feb 17, 2012; 9:57 AM ET
Friday 10:10 a.m
Any time you see a storm system that gives nothing in one place and an inch of water 150 miles away, you know there is a forecast challenge. If the storm track or size of the storm changes, forecasts have to be adjusted in a big way. There's always the question of whether to react to each new model or be more methodical about it by changing things incrementally. We also study the models versus real time weather maps, satellite pictures and radar observations. This video show the way the GFS portrayed things with its 1 a.m. EST Friday run.
This preliminary snowfall map will be reviewed continuously as the storm takes shape:
AccuWeather.com - Joe Lundberg | Potent Storm to Bring Rain, Snow and Severe Weather This Weekend
Feb 17, 2012; 10:30 AM ET
Friday, 11:15 A.M.
If I didn't know better, I think I would call this more of an early-spring storm, rather than a winter storm. Why? For the simple fact there will rain, snow, and severe weather all wrapped into this storm that will get more impressive with time. In most winter storms, you tend not to get much, if any, severe weather, just the snow (and ice) on one side of it, and rain elsewhere. Throw in the fact it will be very mild in the East and Southeast ahead of the storm, and not terribly cold behind it, especially west of the Appalachians, and it seems more suited to a 'spring' storm. But I won't fret over what you or I wish to call it. It will rain, it will snow, and there will be some severe weather.
Here's the big picture view from a pretty picture:
That simplifies things quite a bit, almost too much, in fact! It leaves
out one of the key factors with regard to the path of the storm, and
that's the lead disturbance that will streak across the Upper Midwest
into the northern and eastern Great Lakes later tonight and tomorrow
morning, then drive a weak but very definable cold front to the
Northeast coast tomorrow night. The GFS ensembles are another tool that
really help to show this separation nicely tomorrow morning between this
feature and the storm lagging behind near the Texas Coast:
The model consensus is much tighter today, and while there will still
be some minor changes in the overall storm track and timing, things
look pretty much on target for a track originating along the Upper Texas
Coast and adjacent Northwest Gulf of Mexico waters late tonight and
tomorrow morning, then cutting east-northeastward through northern
Georgia late tomorrow night, and then off the Outer Banks/northeast
North Carolina Coast by early Sunday night.
Aside from limiting the phasing potential of this southern stream
storm and thereby limiting the northward advance of the cloud and
precipitation shield, the other impact of the northern stream
disturbance is to bring cold air to the sidelines ahead of the storm
Saturday night. As the storm deepens Sunday and tracks across the
Carolinas, a northerly wind will drain this colder air southward into
the storms' circulation. In time, this will steadily cool the boundary
layer (finally!) to the point at which falling snowflakes will not melt
before reaching the ground. At this changeover point, it then becomes a
matter of precipitation rates, and the length of time it can snow. Those
two factors will then determine how much snow falls in any given area.
And given the fact it is going to behave more like a spring storm,
rather than a mid-winter storm, there may be some wild fluctuations in
snow fall totals over relatively small distances as banding features
develop. Furthermore, elevation will be another factor in assessing
final snow fall tallies, which is why our initial thinking is that areas
of western Virginia into West Virginia, northeast Tennessee, and
eastern Kentucky will probably have the snow fall totals from this storm
when it all shuts off Sunday night. Many areas here could easily exceed
six inches of snow, and some may eclipse a foot.
As has been my thinking all week long, it will snow in the big cities
like Washington, D.C., Baltimore, and Philadelphia, though after it
starts as rain. But you'll want to be west of these cities to get
healthy snow totals, with the greatest amounts west and northwest of the
nations' capital.
South of these areas, where its mostly or all rain, there will be a
lot of it, and flooding is a real concern from central and East Texas
all the way to southern Virginia. While this won't be precise, the NAM
total precipitation forecast through Sunday night is impressive:
The core areas from central Texas across Louisiana all the way to
North Carolina are forecast to pick up two inches or more of rain. No
doubt some will nearly double that, especially with the expected strong
thunderstorms.
And, of course, it being a spring-like storm, there will be severe
weather. It should start to show up late tonight or tomorrow morning
over parts of Southeast Texas and Louisiana, then spread eastward across
the central and eastern Gulf Coast states later tomorrow and tomorrow
night before ending Sunday morning.
There should be some interesting temperature variations behind this
storm Monday and Tuesday. Where the ground is covered by snow, and it
clears out with winds becoming calm Sunday night, probably west of the
Appalachians, there will be some true pits of cold, with temperatures
ending up several degrees most numerical guidance, and noticeably lower
than surrounding areas without the snow cover. The same is true in and
east of the Appalachians Monday night, especially as high pressure
builds overhead. The nights are still more than 11 hours long, and a
fresh snow pack behind a storm with a clear sky and no wind is ideal for
radiational cooling.
This snow will be largely melted by the middle of next week, though,
especially out of the mountains. Look at the GFS forecasted 850mb
temperatures for Tuesday afternoon:
With a decent amount of sunshine and a nice breeze, that should
easily boost temperatures into the 40s and 50s over the snow fields of
the mid-Atlantic and points west, and as the dew points rise at midweek
ahead of the next storm, much of what remains after that should get
steadily eaten up, by day or by night.
Lest one think that after this storm exits, and the snow melts, that
winter is over, no so fast, my friend! After a mild start to next week,
it finally looks to turn colder in Canada, our usual source region of
cold across the country. And the parade of systems across the Pacific
and into the western U.S. shows no signs of ending. In fact, a couple of
different computer forecasts are jumping on a system in the Rockies and
western Plains late next weekend, one that could tap some of that cold
air and develop into an all out blizzard on one side of the storm, while
more severe thunderstorms try to break out on the warm side. Obviously,
that's a long way off, and much can and probably will change to alter
that specific scenario between now and then. Regardless, the pattern
looks to remain very active going forward through the rest of February
and into early March.
On a brighter note, the best phrase I've heard can now be uttered across the land this weekend:
'Pitchers and Catchers Report.'
Spring cannot be far away now! :)
AccuWeather.com - WeatherMatrix | Confirmation of Snowless, Warm U.S., Cold Europe
Feb 15, 2012; 2:06 PM ET
This far through the winter, it's pretty obvious that much of the United States (certainly the East) has had a lack of snow, while Europe has suffered a harsh cold wave. But in meteorology, it's always important to quantify these things and compare them to history, because people's memories are short and localized. These recent maps and graphs show that these events are, in fact, extreme.
The image above shows the extreme cold in Europe between Jan. 25 and Feb. 1, via a NASA article about the Europe cold wave. Some of these areas are nearly off the chart, with the coldest areas centered around the Black Sea.
It's worth noting that the cold continued for another week after that
map, so we took it one step further to show the departures between Jan.
25 and Feb. 14. Our news story says: "The
average reading of 0.7 degrees below zero F took Rivne to 20 degrees
below normal... The three weeks in Russia averaged almost 25 degrees
below normal in Yashkul, near the Caspian Sea. At least one all-time
record low temperature may have been set when Astrakhan, Russia, hit 29
degrees below zero F early in February." That large of an area of temperatures below 10 to 20 degrees is rarely seen worldwide
.
Flipping the globe, we take look at the U.S. -- extremely warm during
the Jan. 25 - Feb. 1 period, except Alaska, which was even colder
compared to normal than Europe! This came on the heels of an already
warm and snowless winter, which the map below confirms was a nationwide
problem - not just limited to the Northeastern states. I don't know
which image is more pitiful -- the one in December where almost no one
was getting above-normal snowfall, or the February map where a larger
portion of the nation was in a snow drought.
The warmth in the U.S. and Canada has led to extremely low ice levels -- the second least amount of ice cover since 1981. This will lead to unusually late lake-effect snow, something New York state schools should have considered before "giving back" snow days.
Closeup on Forests of the Pacific Northwest
February 17, 2012
acquired January 1 - December 31, 2000
The coastal Pacific Northwest of the United States has the tallest trees in North America, averaging as much as 40 meters (131 feet) in height. It has the densest biomass—the total mass of organisms living within a given area—in the country. But for centuries, it also has been a much-tapped resource for lumber; land-clearing for agriculture and development have also trimmed the woodlands. Both the lumber companies and forest managers have an interest in measuring the health of these forests.
“Resource managers need to see forests down to the disturbance resolution—the scale at which parking lots or developments or farms are carved out,” says Josef Kellndorfer, an ecologist at the Woods Hole Research Center (WHRC). His research team recently took forest mapping down to that level when they released theNational Biomass and Carbon Dataset (NBCD) in April 2011. “We are providing information on a management scale.”
The maps above are a subset of that nationwide mapping project. The top map shows one of 66 mapping zones across the country; in this case, Washington state and a sliver of Oregon. The inset map (lower) shows the fine scale of that forest (the image is roughly 20 kilometers wide), which allows researchers to see the regular patterns of logging and development, and the more erratic shape of areas lost to fires and pests.
Over six years, researchers assembled the maps from space-based radar, satellite sensors, computer models, and a massive amount of ground-based data. Forests were mapped down to a scale of 30 meters, or roughly 10 computer display pixels for every hectare of land (4 pixels per acre). The colors depict the concentration of biomass stored in the trunks, limbs, and leaves of trees. The darkest greens reveal the areas with the densest, tallest, and most robust growth.
A rule of thumb for ecologists is that the amount of carbon stored in a tree equals 50 percent of its dry biomass. So if you can estimate the biomass of all the trees in the forest, you can estimate how much carbon is being stored. If you keep tracking it over time, you can know something about how much carbon is being absorbed from the atmosphere or lost to it.
Human activities have moved a lot of carbon from long-term, stable storage—such as the tall old-growth forests of the Pacific Northwest or the lower, denser stands of the Amazon—into forms with short-term, direct impacts on the environment. When we clear forests, we usually remove tall trees that can store tons of carbon in their trunks, branches, and leaves for hundreds of years. We replace them with croplands or pastures that store less carbon for a shorter time. And paved developments store little to no carbon.
In a recent report by the U.S. Forest Service, researchers noted that while the federal government owns slightly less than 50 percent of the forest land in the Pacific Northwest, it controls more then 67 percent of the old-growth in the region. That percentage is rising not because of new federal acquisitions, but because harvesting removed about 13 percent (491,000 acres) of old- and “late-sucessional” forest on non-federal lands. (The main reason for old-growth loss on federal lands is forest fire.)
“The biggest natural sink of terrestrial carbon lies in our forests and trees,” says Steve Running, a forest ecologist at the University of Montana. “And the biggest natural source of carbon on land is also the forest. So one of the most important things we can do for understanding the carbon budget is to get a better inventory of the carbon we have in our trees.”
To learn more about scientists' efforts to map the world's forests and how much carbon they store, read our latest feature story: Seeing Forests for the Trees and the Carbon: Mapping the World’s Forests in Three Dimensions.
References
- Melinda Moeur, et al, U.S. Forest Service (2011, November) Status and Trends of Late-Successional and Old-Growth Forests. General Technical Report PNW-GTR-853, U.S. Department of Agriculture. Accessed February 16, 2012.
- Map by Robert Simmon, based on data from Woods Hole Research Center. Caption by Mike Carlowicz.
- Instrument:
- Landsat 5 - TM
Why Was 2011 Such a Deadly Tornado Year?
Feb 17, 2012; 1:26 PM ET
Last year, 2011, went down in the record books as the fourth deadliest tornado year ever in the United States with 550 fatalities.
1925 was the deadliest year in the U.S., with 794 killed, according to National Oceanic and Atmospheric Administration (NOAA). That year is infamous for the Tri-State tornado, the longest-tracking, deadliest tornado on record. The tornado's path went through portions of Missouri, Illinois and Indiana, over 219 miles long. The twister killed 695 people along its path.
There were 552 deaths in 1936 and 551 deaths in 1917, ranking as the second and third most deaths caused by tornadoes in a year. According to the Storm Prediction Center (SPC), the yearly average for tornado deaths is around 60.
In this April 28, 2011 photo, Alabama Gov. Robert Bentley and his wife Dianne view tornado damage in Tuscaloosa, Ala. A spawn of deadly tornadoes hit the state on Bentley's 100th day in office. (AP Photo/Dave Martin)
2011 had an unusually high number of large, destructive tornado outbreaks; 1,709 tornadoes touched down, a close second to the record 1,817 tornadoes set in 2004. In comparison, the average number of tornadoes per year over the past decade is around 1,300.
April 2011 was the most active tornado month ever in the U.S. with 753 twisters touching down. In April alone, 364 people were killed by tornadoes.
Why So Many Tornadoes in 2011?
A key ingredient for the violent severe weather in 2011 was a very strong jet stream. La Niña, a phenomenon where the sea surface temperature in the central and eastern Pacific around the equator are below normal, helped to cause the strong northern jet stream, which frequently plunged into the South. This set the stage for powerful supercell thunderstorms, which are the type of storms that spawn tornadoes.
A key ingredient for the violent severe weather in 2011 was a very strong jet stream. La Niña, a phenomenon where the sea surface temperature in the central and eastern Pacific around the equator are below normal, helped to cause the strong northern jet stream, which frequently plunged into the South. This set the stage for powerful supercell thunderstorms, which are the type of storms that spawn tornadoes.
People typically think of "Tornado Alley" as the corridor from Texas to Kansas that is frequently hit by tornadoes in the spring. Warm, humid air from the Gulf of Mexico clashes with drier air from the Rockies. During 2011, many tornadoes touched down east of the typical "Tornado Alley," which is often the case in La Niña years. More densely populated areas sit in the path of severe storms capable of spawning tornadoes.
Tornadoes Hit Many Cities, Communities Outside of "Tornado Alley"
"Last year was an exceptionally deadly year because city after city got hit. Some of them were far outside of 'Tornado Alley.' My friend, Jenna Blum, coined the term 'Metronado,' which is what we had last year," Mike Smith, senior vice president of AccuWeather Enterprise Solutions said.
"Last year was an exceptionally deadly year because city after city got hit. Some of them were far outside of 'Tornado Alley.' My friend, Jenna Blum, coined the term 'Metronado,' which is what we had last year," Mike Smith, senior vice president of AccuWeather Enterprise Solutions said.
Minneapolis, Minn., Springfield, Mass., Raleigh, N.C., St. Louis, Mo., Birmingham, Ala., Jackson, Miss., Oklahoma City, Okla., New York City, N.Y., and Philadelphia, Pa., are among the cities where tornadoes touched down in 2011.
Two of the most deadly tornadoes touched down in Joplin, Mo., on May 22, 2011 and Tuscaloosa, Ala., on April 27, 2011.
"No matter how good the warnings are, if you take a densely populated area and put an F-4 or F-5 tornado in there, tragically, people are going to lose their lives," Smith added.
Some strong tornadoes also touched down far outside of "Tornado Alley," where people are less prepared for violent severe weather.
Bricks and debris that fell from a building lay on top of cars after a report of a tornado in Springfield, Mass., Wednesday, June 1, 2011. A tornado struck downtown Springfield, one of Massachusetts' largest cities, scattering debris, toppling trees, and frightening workers and residents. (AP Photo/Jessica Hill)
Springfield, Mass., was hit by an rare EF-3 tornado on June 1, 2011. "This was the first major tornado to hit Massachusetts since 1953," Smith said.
AccuWeather.com's Severe Weather week starts Sunday, Feb. 19-Feb. 25. The outlook for severe weather and tornadoes in 2012 will be released on Monday, Feb. 20.
Inadequate Shelters Led to More Deaths in 2011
Another factor in how deadly tornadoes were in 2011 was inadequate shelters both in solid structure homes and mobile home parks.
Another factor in how deadly tornadoes were in 2011 was inadequate shelters both in solid structure homes and mobile home parks.
The safest place to take shelter during a tornado is in the lowest interior room of a house or building, preferably in a basement, but there are areas in the country where people do not have basements.
Many people that live in "Tornado Alley" and other areas of the country frequently hit by tornadoes do not have basements, while other communities far outside of "Tornado Alley" do have basements.
"Places like Massachusetts have basements -- well outside of 'Tornado Alley.' Oklahoma, almost no one has a basement. It's local building customs, soil conditions, etc., that dictate whether people have basements. In Joplin, almost no one had a basement, but in St. Louis, same state, almost everyone did," Smith said.
Many mobile homes were devastated by tornadoes in 2011, leaving many to debate whether mobile home parks should be required to have community shelters.
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