Big Temperature Turnaround For Mid-Atlantic, Northeast

Photo courtesy of Photos.com.

Mar 10, 2012; 3:49 PM ET

Temperatures are going to take a 180-degree turn on Sunday, with much milder air surging through the eastern part of the country.
Temperatures remain on the chilly side at the present time across the mid-Atlantic and Northeast, but that's all going to change by Sunday.
An area of high pressure anchoring itself off the East Coast will send a surge of milder air into the northeastern quadrant of the country.
Most cities and towns from Washington, D.C., through Philadelphia and Allentown, Pa., along with New York City and Boston will become 15-20 degrees warmer than what it was today.

That translates to widespread high temperatures in the 50s and 60s, which is a welcome sight for those still on Spring Break or getting ready to go on Spring Break.
Below is a list of Saturday's actual high temperatures vs. the forecasted high for Sunday (in degrees Fahrenheit):

City	Actual High Thru 3 P.M. Saturday	Forecasted High Sunday
Washington, D.C.	48	62
Philadelphia, Pa.	42	60
New York City	41	59
Boston, Mass.	38	54

The pleasant temperatures will be accompanied by bright sunshine and little in the way of wind.
The mild weather won't stop here either!
As Meteorologist Matt Alto reported earlier Saturday, as unseasonably warm weather spans across much of the eastern part of the country."
High temperatures by midweek will reach the 70s across the Washington, D.C., and Baltimore region with 60s being felt all the way northward into central New England.

Big Temperature Turnaround For Mid-Atlantic, Northeast

Severe Storms to Rumble Across the Arklatex Sunday

Photo courtesy of Photos.com

Mar 10, 2012; 2:30 PM ET

A potent storm system coming out of the Four Corners region will spark a round of damaging thunderstorms across the Arklatex on Sunday.

All signs point to a decent setup for severe thunderstorms Sunday, especially during the afternoon and evening hours.

Strong winds coming out of the Gulf region combined with abundant moisture and the approaching storm system will set the stage for showers and strong thunderstorms from eastern Oklahoma and northeastern Texas through much of southern Arkansas and northern Louisiana.

Widespread rain and a few thunderstorms will be ongoing across eastern Texas, Oklahoma and western Arkansas Sunday morning.

As stronger winds aloft move into the region, the scattered thunderstorms will organize into a more solid band of storms.

These storms will increase in intensity into Sunday afternoon, especially with a few breaks of sun which will help to further destabilize the atmosphere.

Damaging wind gusts and torrential, blinding downpours appear to be the main threats from these thunderstorms from Tyler and Longview, Texas, through Shreveport and Monroe, La., northward to Little Rock, Ark.

AccuWeather.com meteorologists are also becoming concerned for increasing tornado potential across this region. There is enough twisting of the winds in the atmosphere that a few tornadoes could develop, especially if there is more sunshine than we're currently expecting.

The best chance for tornadoes looks to be across central and southern Arkansas where the winds are more favorable for rotating storms.

Farther to the west, beneficial rains will fall in central and northeastern Texas into the day on Sunday.

For more information on the upcoming severe weather potential, please visit the AccuWeather.com Severe Weather Center.

Stay tuned to AccuWeather.com for more information on the tornado potential across the Arklatex region on Sunday as well as local media outlets for potential watches and warnings.

Severe Storms to Rumble Across the Arklatex Sunday

Welcome Texas Rains Continue This Weekend

Mar 10, 2012; 11:20 AM ET

Welcome rains across Texas will continue through the weekend, helping to alleviate the moderate to severe drought that continues.

Nearly 86.5 percent of the state of Texas continues to suffer from moderate to severe drought conditions with the worst impacts across the west and south.

Just three months ago, 100 percent of the state was suffering from drought conditions. Since that time, substantial soaking rains have virtually wiped out the drought across just over 6 percent of northeastern Texas in the vicinity of the Red River.

More relief is on the way to central and eastern Texas tonight through Sunday as steady rains fall across these regions.

Moisture streaming northward ahead of an approaching disturbance will continue to spark moderate to locally heavy downpours across the eastern half of the state.

By Sunday afternoon, rainfall totals will likely be in the one- to three-inch range from Tyler, Texas, through Paris, Texas.

Even the Dallas-Fort Worth metroplex could pick up greater than an inch of rainfall which would put them well above normal for the year thus far.

Farther to the south, rainfall totals of one-half to one inch will be welcome with open arms from Beaumont to Houston to Corpus Christi and Del Rio where the drought continues to significantly impact the region.

While the news is good across central and eastern Texas, things aren't so good across West Texas and the Rio Grande Valley.

Much lighter rains in the form of spotty showers will fall in cities such as Brownsville, Port Isabel, and Midland where rains are desperately needed.

This is a current image of the ongoing drought in Texas courtesy the U.S. Drought Monitor. The darker reds across western and southern Texas represent the most severe conditions.

The storm responsible for these rains will also spark a few strong thunderstorms across the Arklatex region on Sunday.

Cities in line for severe weather include Little Rock, Ark., Shreveport, La., and Longview, Texas.

More information on the severe weather potential can be found in the AccuWeather.com Severe Weather Center.

Welcome Texas Rains Continue This Weekend

Typical Weather Returns to Hawaii After Flooding, Tornado

Photo of large hail in Hawaii posted on Twitter by Maya S. on March 9, 2012.

Mar 10, 2012; 11:10 AM ET

Flooding, landslides and even a tornado recently pummeled the Hawaiian Islands.

The National Weather Service in Honolulu confirmed that an waterspout moved onshore as an EF-0 tornado in Lanikai around 7:10 AM local time Friday morning. The twister then continued southwestward, impacting parts of the Enchanted Lakes Subdivision in Kailua.

The tornado damaged or destroyed several roofs, snapped trees, knocked down power lines and destroyed road signs.

Winds associated with the tornado were estimated at 60-70 mph. It had an average width of 20 yards and a damage path that spanned 1.5 miles.

Multiple landslides the last several days have resulted in a deluge, blocking highways in Hanalei, Kalihiwai and Koloa.

Bus service north of Hanamaulu, Hawaii, was cancelled for a time due to the flooding rainfall.

Some of the thunderstorms became so violent that they produced hail with diameters up to 2 inches in Kailua and Kaneohe. Some of the hail-producing thunderstorms have lasted for half an hour.

RELATED: 

 Three-Inch Hail, 46 Inches of Rain in Hawaii

"

What [went on] in Hawaii is a symptom of the change from La Niña to El Niño coming on," according to AccuWeather.com Expert Senior Meteorologist Henry Margusity.

La Niña is a phenomenon classified by below-normal water temperatures of the eastern and central equatorial Pacific Ocean, while El Niño occurs when there is above-normal water temperatures in the same zone.

Temperatures have been warming up in the Pacific over the last month.

"Think of the Pacific Ocean as either a big pot of cold water or hot water," explained AccuWeather.com Expert Senior Meteorologist Henry Margusity. "The water is either going to cool the atmosphere or warm it. Because you are making a change to one area of the atmosphere, everything else has to change around it. Thus, the whole weather pattern changes for the Northern Hemisphere."

When water temperatures warm, the air above it warms, leading to more rising air and thunderstorms in that area. Other areas of the atmosphere will cool with sinking air and calm conditions in response, because the atmosphere is always trying to reach a balance.

"Hawaii holds some of the world's rainiest locations, but over the weekend, things got a little out of control," AccuWeather.com Meteorologist Jesse Ferrell said. "Local rivers and creeks came out of their banks. NWS reports also indicated that a number of roads were closed due to flooding, the Llikai Hotel at Waikiki was set ablaze by lightning, and most incredibly, hail of 1.5 inches in diameter was observed in Honolulu when a rare supercell thunderstorm moved over the island."

Hanelei, Hawaii, received 35.97 inches of rain in just over two days.

The good news for travelers and residents of the state is that a more typical weather pattern is developing and will persist into next week.

The storm that wreaked havoc on the state will continue to track westward away from the Hawaiian Islands, leaving behind a more normal, trade wind pattern for this time of year.

Much drier weather is forecast beginning on Sunday with just the typical trade wind showers from time to time.

  

Typical Weather Returns to Hawaii After Flooding, Tornado

NHC Implements New Hurricane Categorization Scale

Mar 10, 2012; 11:03 AM ET

Image courtesy of Photos.com

The Saffir-Simpson Hurricane Wind Scale (SSHWS) is a 1 to 5 categorization based on a hurricane's intensity at an indicated time, according to the National Hurricane Center (NHC). The scale is undergoing a minor modification in 2012 to resolve "awkwardness associated with conversions among the various units used for wind speed in advisory products."

Essentially, the new modification is to help clarify categorization of wind speed measurements based on miles per hour (mph), kilometers per hour (km/h) and knots. There is an inherent uncertainty when estimating wind speeds for tropical cyclones. Generally, wind speeds are rounded because it's unrealistic to identify exact wind speeds. So, these numbers are rounded to the nearest "5." For example, 132 mph would be rounded to 130 mph, while 137 knots would be rounded to 140 knots.

 

The new categories are shown in this graph from the NHC.

This provides a problem, specifically for Category 4 classification. Category 4 used to be defined as 131 to 155 mph (or 114 to 135 knots or 210 to 259 km/h). This has caused a problem in conversions. For example, if a reading is 115 knots, it is a Category 4 hurricane. However, when 115 knots is converted to mph (132.3 mph), and it is rounded to the nearest "5" (130 mph), the hurricane is then defined as a Category 3 hurricane.

The new scale will alleviate this issue. Category 1 (64 to 82 knots) and Category 2 (83 to 95 knots) will remain the same, but Category 3 (formerly 96 to 113 knots) will now be measured as 96 to 112 knots (or 111 to 129 mph or 178 to 208 km/h). Category 4 will now be identified as 113 to 136 knots (or 130 to 156 mph or 209 to 251 km/h), and Category 5 will be defined as 137 knots or higher (or 157 mph or higher or 252 km/h or higher).

 

This breakdown from the NHC shows the differences between the old scale and the new version.

Now, when knot-based measurements are used to categorize hurricanes, the conversion will not affect to which category the hurricane belongs. The NHC has stated that this new scale will not affect any previous categorizations of past hurricanes and has only been implemented to make classifications easier.

Information for this story as provided by the NHC.

NHC Implements New Hurricane Categorization Scale

Nearing the One Year Anniversary of Japanese Tsunami

In this photo taken Thursday, March 1, 2012, a worker stands amid abandoned cars damaged by the March 11 tsunami in Minamisanriku, Miyagi Prefecture, northeastern Japan. (AP Photo/Shizuo Kambayashi)

Mar 10, 2012; 10:48 AM ET

The one year anniversary of the major earthquake that sparked a massive tsunami near Japan will occur at 12:46 a.m., EST on March 11. Even almost a year after the tragedy, parts of Japan are still trying to recover.

The earthquake itself was a 9.0 magnitude that occurred just off the east coast of Japan at a depth of about 20 miles, according to the USGS. The 9.0 magnitude quake is tied for the fourth strongest earthquake dating back to the year 1900. Following this quake, there have been hundreds of after shocks rating over 4.5 magnitude, with several in the past week alone.

This powerful quake resulted in an equally powerful tsunami that struck the eastern coastline of Japan. A research team from Yokohama National University and University of Tokyo estimated the tsunami reached a maximum run-up height of 127 feet near Miyako, becoming the highest such report since records began in Japan. The tsunami measured over 20 feet in many locations along the Japanese coastline, while areas as far away as Chile and the United states reported a tsunami surge over 6 feet.

RELATED: Japan Tsunami Rubble May Be Headed for Hawaii

The death toll in Japan from this disaster topped 15,000 with more than 3,000 people still missing. A large majority of the fatalities occurred due to drowning following the tsunami.

Damages from the earthquake and tsunami are still being assessed with estimates well into the tens of billions of dollars. The Japanese National Police Agency reported that over 150,000 buildings were damaged or destroyed by the earthquake and tsunami. Tohoku Electric Power reported nearly 4.4 million households were without power for at least some time following the quake and tsunami.

According to the Japan Times nearly 10 percent of Japanese fishing ports were damaged or destroyed by the tsunami.

The other main story to come from the earthquake and tsunami was the meltdown of a reactor at the Fukushima Daiichi Nuclear Power Plant, which occurred when the tsunami crashed over the tsunami wall and inundated parts of the facility. Cleanup efforts are ongoing in and around the site of Power Plant to prevent further contamination of soil and water.

Nearing the One Year Anniversary of Japanese Tsunami

Widespread Warmth Expected Next Week

Mar 10, 2012; 10:35 AM ET

Spring fever will be in full-bloom next week as unseasonably warm weather spans across much of the eastern half of the country.

The warm spell is expected to last longer than the warmup that expanded across much of the nation this past week.

The coming warmup started on Friday across parts of the northern and central Plains as well as the northern Rockies as afternoon temperatures warmed into the 60s and 70s in some locations.

Noticeably warmer air will continue to surge northward into this region again today as afternoon temperatures warm into the middle to upper 60s with some locations exceeding 70. Such temperatures will be 10 to 20 degrees higher than normal on average.

Temperatures will be on the rise as well today across the Great Lakes, the Ohio and Tennessee valleys as well as much of the Southeast with temperatures averaging nearly 10-20 degrees warmer than the highs on Friday.

Cold air will remain in place across the Northeast today; however, its stay will be short-lived as a surge of warm air is knocking on the front door.

As high pressure slides off the mid-Atlantic coast on Sunday, a warm southerly breeze will usher the warmer air into the East.

While afternoon highs across much of the Northeast will be in the 30s and 40s today, much of the region will enjoy plenty of sunshine as well as a warm afternoon on Sunday with many locations having highs in the 50s.

People from the Plains to the Northeast and mid-Atlantic will be busting out the shorts and t-shirts early next week. Locations from Kansas City to Washington, D.C. will climb into the 70s, while locations from Fargo to Boston reach into the 60s.

Unlike warmups experienced during the summer, humidity levels will be quite comfortable as a refreshing southerly breeze accompanies the warmth.

Temperatures will continue to remain warm throughout the coming week with no shots of cold air expected with the jet stream remaining to the north across southern Canada.

Widespread above-normal temperatures are expected across the eastern two-thirds of the country throughout the week.

How warm will it get in your town or city? Check the latest local forecast here on AccuWeather.com.

 

Widespread Warmth Expected Next Week

Storms Aim for West Coast, Northwest First

Mar 10, 2012; 10:14 AM ET

A new series of storms moving into the Northwest beginning this weekend will bring rain, colder air and lowering snow levels.

While none of the storms appear to be powerhouses in terms of widespread damaging winds, they will bring substantial precipitation as a cumulative effect over time.

Snow levels may dip as low as 500 feet around Seattle and to near 1,000 feet around Portland, Ore., later this weekend. This will allow some wet snow to mix in on the hills, while rain falls at sea level.

As the atmospheric parade continues, the rain and mountain snow will push inland and southward over the West into next week.

RELATED: Hawaii Hammered by Downpours, Thunderstorms

Japan Tsunami Rubble May Be Headed for Hawaii

In the Cascades, a foot or more of snow will fall with several inches of snow in store for the passes, including over I-90. Snow will also push into the northern Rockies this weekend, before penciling out east of the Divide.

As each storm pushes ashore, a shift in the jet stream will allow the storms to drive more to the south into more of California and Nevada.

It is possible that during next week substantial snow will fall across much of the Sierra Nevada. Drenching rain could also spread southward along coastal areas and interior valley areas of California during this time.

 

Storms Aim for West Coast, Northwest First

Rodeo of Rain for Texas

Mar 10, 2012; 6:08 AM ET

More rain is in store for Texas and other South Central states in the coming days.

The atmosphere has been lassoing moisture-rich storms in Texas and other portions of the South Central states of late and indications are this rainfall rodeo will continue in the short-term.

Rains have come to much of Texas this winter and more rain will fall on portions of the Lone Star State into the weekend and beyond.

The overall weather pattern will continue to bring episodes of rain to very needy and less needy areas of the state into next week.

A slow-moving storm will continue to drop substantial rain in central and western counties through Saturday.

There is the potential for over an inch of additional rain in some locations, which have already received over a half inch at the end of this week.

This particular storm will wander eastward and will spread northward late in the weekend into early next week.

Since areas from northeastern Texas to part of the lower Mississippi Valley are not experiencing a rainfall shortage, the risk for flash flooding will again increase as the storm will continue to produce heavy rainfall along the way, especially where thunderstorm downpours repeat.

Indications are that yet another episode of rain may evolve for portions of Texas during the middle and latter part of next week. Details on this rainfall potential will unfold in the coming days.

During the middle to latter part of the spring, a drier pattern may again evolve for central and western Texas into the Four Corners, depending in part on the behavior of the El Nino Southern Oscillation (ENSO).

Dallas is coming off its sixth-wettest winter (December-February) on record with 12.41 inches. The wettest winter was the 1931-1932 season. This winter was just ahead of the 2000-2001 season when 12.18 inches of rain fell.

Many places in western and central Texas, western Oklahoma and eastern New Mexico still need more rain, beyond what this storm will provide.

 

Rodeo of Rain for Texas

AccuWeather.com - Brett Anderson | Long Range Computer Model Outlook for Spring and Summer

Mar 9, 2012; 11:36 AM ET

The new ECMWF seasonal forecast, which updates once a month is now released on the 8th of each month.

The model continues to forecast above normal temperatures across much of the eastern two-thirds of North America from the upcoming Spring and right into the summer, though it shows near-normal temperatures for the Northeast U.S. and most of eastern Canada this summer.

One other thing that was striking is that the model steadily weakens the La Nina this Spring and trends toward a weak El Nino later in the summer. Keep in mind, even if this happens, there is a lag effect and so the overall atmosphere could still have the look of a La Nina through the Spring and not show any influence from a weak El Nino until the end of the year or next year.

Also, the model is forecasting a busy hurricane/typhoon season for the central and western Pacific region, while a drier, quieter season is indicated for the Atlantic basin.

ECMWF Spring 2012 forecast interpretation.

 

 

ECMWF Summer 2012 forecast interpretation. 

AccuWeather.com - Brett Anderson | Long Range Computer Model Outlook for Spring and Summer

AccuWeather.com - Climate Change | Significant Loss of Thicker, Multi-Year Sea Ice

Mar 9, 2012; 10:32 AM ET

A new NASA study has found that the oldest, thickest sea ice in the Arctic region has been disappearing at a faster rate than younger, thinner sea ice.

Losing more of the thicker sea ice makes the entire northern sea ice cap much more vulnerable to an overall, accelerated decline.

According to the study, which was led by NASA's Joey Comiso, the area covered by multi-year ice has been shrinking by -17.2 percent per decade.

The two NASA images below are quite striking. The first image shows the sea ice coverage from Nov-Jan 1980. The thicker, multi-year ice can be seen as bright white, while the average, thinner ice closer to the edges is either milky white or light blue.

1980

2012

By Jan 2012, you can see the dramatic reduction in the thicker, multi-year ice.

Excerpts from the NASA Earth Observatory article......

The thickest "multi-year" ice survives through two or more summers, while young, seasonal ice forms over a winter and typically melts just as quickly as it formed. Scientists also describe a third category: "perennial" ice is all ice cover that has survived at least one summer. All multi-year ice is perennial ice, but not all perennial ice is multi-year ice.

Comiso found that perennial ice extent has been shrinking at a rate of -12.2 percent per decade, while its area is declining at a rate of -13.5 percent per decade. These numbers indicate that multiyear ice is declining faster than the perennial ice that surrounds it.

Key quote from Comiso via NASA EO......

"The Arctic sea ice cover is getting thinner because it's rapidly losing its thick component," Comiso said. "At the same time, the surface temperature in the Arctic is going up, which results in a shorter ice-forming season. It would take a persistent cold spell for multi-year sea ice to grow thick enough again to be able to survive the summer melt season and reverse the trend."

AccuWeather.com - Climate Change | Significant Loss of Thicker, Multi-Year Sea Ice

AccuWeather.com - Meteo Madness | A Little Snow for the Great Lakes and Northeast

Mar 9, 2012; 9:33 AM ET

Not much to talk about today. It's going to get warm after the shot of cold air moves out of the Great Lakes and Northeast. I posted a map below from the RR model showing the total snowfall for the clipper coming on through. All that snow will be gone by Monday when the warmth returns.

Rapid Refresh Snow Image

AccuWeather.com - Meteo Madness | A Little Snow for the Great Lakes and Northeast

AccuWeather.com - Elliot Abrams | Cold Briefly, then Mild for a Long Time

Mar 9, 2012; 8:12 AM ET

Friday 9 a.m.

The video today shows colder air moving into the Northeast. Also, some places that were in the 50s and 60s will have snow. It has been snowing this morning from southern Michigan to western New York, and that snow could streak eastward across central and southern New England tonight.

Tomorrow's temperatures will not get out of the 30s from Maine to northern Pennsylvania, However, mild air comes back in a big way on Sunday afternoon. Numerical forecast models suggest it will be mild to warm in the Northeast next week and the week after!

The National Weather Service's GFS model (the one I use most often in my videos) is run many times to produce an ensemble of solutions. Each run has slightly different initial data, a practice justified by the fact that a set of "real" observations does not exist for all points on Earth. Anyway, if you plot certain contours, such as the 500 mb flow aloft, you can see how well the model runs agree or don't agree with each other out into the future. Because these lines may go all over the place, the plots are called spaghetti plots. This map shows a plot for Monday, March 19. The individual lines for each contour do not all go the same way, but all of them suggest that the air coming into the Northeast originates in the Southwest.

AccuWeather.com - Elliot Abrams | Cold Briefly, then Mild for a Long Time

Rodeo of Rain for Texas

More rain is in store for Texas and other South Central states in the coming days.

Mar 9, 2012; 2:25 PM ET

The atmosphere has been lassoing moisture-rich storms in Texas and other portions of the South Central states of late and indications are this rainfall rodeo will continue in the short-term.

Rains have come to much of Texas this winter and more rain will fall on portions of the Lone Star State into the weekend and beyond.

The overall weather pattern will continue to bring episodes of rain to very needy and less needy areas of the state into next week.

A slow-moving storm will continue to drop substantial rain in central and western counties through Saturday.

There is the potential for over an inch of additional rain in some locations, which have already received over a half inch at the end of this week.

This particular storm will wander eastward and will spread northward late in the weekend into early next week.

Since areas from northeastern Texas to part of the lower Mississippi Valley are not experiencing a rainfall shortage, the risk for flash flooding will again increase as the storm will continue to produce heavy rainfall along the way, especially where thunderstorm downpours repeat.

Indications are that yet another episode of rain may evolve for portions of Texas during the middle and latter part of next week. Details on this rainfall potential will unfold in the coming days.

During the middle to latter part of the spring, a drier pattern may again evolve for central and western Texas into the Four Corners, depending in part on the behavior of the El Nino Southern Oscillation (ENSO).

Dallas is coming off its sixth-wettest winter (December-February) on record with 12.41 inches. The wettest winter was the 1931-1932 season. This winter was just ahead of the 2000-2001 season when 12.18 inches of rain fell.

Many places in western and central Texas, western Oklahoma and eastern New Mexico still need more rain, beyond what this storm will provide.

Rodeo of Rain for Texas

Quick-Hitting Snow for Northeast

Mar 9, 2012; 2:24 PM ET

The springlike warmth which surged into the East earlier this week will briefly become a distant memory, especially for those across the Northeast into Saturday.

While many people were sleeping Thursday night, a strong cold front swept through the region, bringing some steady rain along with much colder air.

With this colder air surging into the Northeast behind the departing front, a fast-moving and quick-hitting upper-air disturbance will bring some snow tonight into early Saturday morning.

Snow has been sliding into portions of western New York Friday afternoon.

Buffalo and Rochester could see some snow falling from the sky by lunchtime.

The period of snow showers will move across the Finger Lakes region and the rest of upstate New York before entering southern New England through this evening, just in time for rush hour in Albany.

The snow may be briefly heavy at times which could reduce visibilities across the region. Motorists who may encounter heavier snow bands should use caution.

Although no major accumulations are expected, some locations could see between 1-3 inches of snow with locally higher amounts not out of the question, especially in the higher terrain.

Due to an unusually mild winter, most of the Great Lakes remain unfrozen. Areas downwind of Lake Ontario will have the best chance for higher snowfall amounts thanks to some extra lake-enhancement.

Snow showers will linger through tonight and early Saturday morning, especially across parts of New England.

Lingering lake-effect snow showers south and east of Lake Ontario will begin to wind down Saturday morning as high pressure and drier air builds into the East.

High pressure will continue to build across the East Coast on Sunday, bringing more springlike warmth to the Northeast to close out the weekend.

Any snow that does stick will likely be entirely melted by Sunday as warmer air is ushered into the region.

Those with spring fever will be happy to hear that the pattern setting up for next week shows no signs of this warmth to leave anytime soon.

Quick-Hitting Snow for Northeast

Storms Aim for West Coast, Northwest First

Mar 9, 2012; 3:08 PM ET

A new series of storms moving into the Northwest beginning this weekend will bring rain, colder air and lowering snow levels.

While none of the storms appear to be powerhouses in terms of widespread damaging winds, they will bring substantial precipitation as a cumulative effect over time.

Snow levels may dip as low as 500 feet around Seattle and to near 1,000 feet around Portland, Ore., later this weekend. This will allow some wet snow to mix in on the hills, while rain falls at sea level.

As the atmospheric parade continues, the rain and mountain snow will push inland and southward over the West into next week.

RELATED: Hawaii Hammered by Downpours, Thunderstorms

Japan Tsunami Rubble May Be Headed for Hawaii

In the Cascades, a foot or more of snow will fall with several inches of snow in store for the passes, including over I-90. Snow will also push into the northern Rockies this weekend, before penciling out east of the Divide.

As each storm pushes ashore, a shift in the jet stream will allow the storms to drive more to the south into more of California and Nevada.

It is possible that during next week substantial snow will fall across much of the Sierra Nevada. Drenching rain could also spread southward along coastal areas and interior valley areas of California during this time.

 

 Storms Aim for West Coast, Northwest First

Rainy Day for Parts of the U.S.A.

Photo courtesy of Photos.com.

Mar 8, 2012; 8:20 PM ET

After a warm Wednesday for parts of the U.S., rain moved in from Texas to New England. An unseasonable warmth in the Southeast mixed with colder air from the North caused a large swath of rain to cut across the country on Thursday.

"Basically, we have chilly air in the northern Plains, unseasonably warm air in the southeast and in between we've got a frontal boundary," AccuWeather.com Expert Senior Meteorologist Dave Dombek said. "The cold air and warm air are converging and creating this massive amount of rain across the U.S. The warm winds are blowing up from the South, and the colder winds are blowing in from the North and the Northwest. It's a strong contrast zone."

Even with the rain reaching a large portion of the U.S., several major cities along the Eastern Seaboard stayed dry.

"The rain didn't reach places like Philadelphia, New York, Boston or Washington, D.C., that's why temperatures were unusually warm today," said Dombek. "Often times you'll see a large pattern of rain following the sudden increase temperature similar to what a large part of the U.S. saw yesterday. In fact, many times this kind of setup can lead to severe weather, but luckily we mainly just received rain in a lot of places today. There were some strong thunderstorms in areas in the South, but it wasn't even close to as bad as the outbreak of severe weather we saw last week."

As we move through the weekend, the rain should move off. However, it's not over yet. Rain will return to Texas by the end of the weekend.

"I think we'll see the rain move eastward as we get in through the weekend," said Dombek. "There will still be some rain for the Southeast, and then we'll see a growing area of rain later in the weekend for Texas, Oklahoma and the Plains states. Basically, this rain will push south, then weaken for a day or so, then regenerate another area of rain. By Sunday, the rain will hit, then it will move northeast into the Tennessee and Ohio valleys Sunday night into Monday."

Even though the rain will return, temperatures are expected to remain above normal. It will again feel as though an early spring has sprung for several areas across the U.S.

"It's going to be warm despite the rain next week," said Dombek. "It's a totally different situation (than this week) as you get into next week. You don't have that contrast zone anymore. All the cold air just retreats and then it's gone. Now, it's operating on that boundary. The cold air will come for a day or so, retreat by Sunday, and then it's gone."

According to AccuWeather.com Meteorologist Brian Edwards, wintry precipitation is highly unlikely next week, and the warm temperatures should continue.

"Even for places where it rains next week, it will still be warm," said Dombek.

Rainy Day for Parts of the U.S.A

Lake-Effect Snow Showers and Flurries Friday

Mar 8, 2012; 10:40 AM ET

Lake-effect snow showers and flurries will fly across Great Lakes and Northeast tonight into Friday for perhaps the last time this season.

As we head deeper into March and closer towards spring, intrusions of cold air become less and less frequent, thus limiting lake-effect snow.

In addition, the battle between warm and cold is often won by the warm air, again limiting lake-effect snow.

Still, if a bit of cold air can pass over the Great Lakes, like it will tonight and Friday, a bit of lake-effect snow can develop.

A strong cold front will blast through the Northeast tonight into Friday and much cooler air will push into the region behind the front. The springlike warmth that surged into the East will be a distant memory, at least for a time.

Due to such an unusually mild winter, most of the Great Lakes are still unfrozen, giving the opportunity for lake-effect snow showers and flurries.

Areas downwind of Lake Ontario will have the best chance of seeing a coating to an inch or two of snow on Friday.

Residents who will be traveling in these areas should use extra caution while driving on snow-covered roads and should watch out for slick spots.

Looking ahead, high pressure will build into the region for the weekend and another springlike surge of warmth will return for the start of next week. There are signs that this return of warmth across the central and eastern United States might not leave anytime soon.

Lake-Effect Snow Showers and Flurries Friday

Heavy Thunderstorms and the Last Lake Snows

Mar 8, 2012; 9:31 AM ET

Comments:

1. Probably the last real shot of cold air will move across the northern tier of the country the next two days. Once the cold air moves it, spring will come in and warmth should dominate for a few weeks. The cold air coming across the Great Lakes will mean a last shot of lake-effect snows for areas of the northern and eastern Great Lakes. We also have a clipper that will move across these areas, enhancing the lake snows and flurries Friday. By Sunday, the cold air will be gone and temps will be off to the races.

2. I downplayed the severe storms in the area shown on the map. There is a lot of cloud cover and storms already have developed which will hold down the heating and the storm potential. I think most of the storms will be heavy rain and gusty wind producers. 

AccuWeather.com - Meteo Madness | Heavy Thunderstorms and the Last Lake Snows

Daylight Saving Time Begins Sunday

Mar 8, 2012; 2:01 PM ET

It's almost that time of the year to spring forward!

At 2:00 a.m. Sunday, March 11, clocks will be set ahead one hour. Most digital clocks and cell phones automatically spring forward, but other appliances and clocks in your home or vehicle might not.

Most of the U.S. and about 70 other countries observe daylight saving time. In the U.S., Arizona and Hawaii are exceptions.

The first suggestion of switching to daylight saving time was made by Benjamin Franklin in 1784.

In a letter to the Journal of Paris called An Economical Project, Franklin proposed that people would save money by burning fewer candles and less oil in their lamps if they changed their clocks, according to WebExhibits.

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Spring Checklist for Homeowners

Besides changing the clocks ahead an hour, daylight saving time is a good time to take inventory of your house and check batteries in smoke detectors. For a list of more home safety tips to check during the time change, click here

Daylight Saving Time Begins Sunday

Why Was It So Warm Wednesday?

Mar 8, 2012; 3:08 PM ET 

Even though there are still nearly two weeks of winter left this year, Wednesday felt like spring had already sprung for parts of the U.S.

"The unseasonably warm weather is mainly in the East and across the Plains," AccuWeather.com Meteorologist Brian Edwards said. "It's not bad out in California, but it's cooler up in the northern Plains, the northern Rockies and the Four Corners region. The widespread warmth has mainly been across the central East."

Warm air being pushed up from the tropics and the Gulf has caused warm temperatures today.

"The reason you have all this warmth is due to a large area of high pressure at the surface that's set up off the East Coast," said Edwards. "So, the flow around that high pressure system is clockwise and it pumps in a lot of warmer air from the south. Warm air comes up from the Gulf region and from the tropics. All that warm is being funneled up into the Ohio valley, the Tennessee valley, the mid-Atlantic and the Northeast."

With the warmer air, precipitation will also move in on Thursday.

"The warm air is out ahead of a front approaching from the West which will bring some rain to a lot of places Thursday," said Edwards. "It will start to rain first in western New England and western parts of the mid-Atlantic. That will transition into the rest of the Northeast and remainder of the mid-Atlantic Thursday evening."

Today's warm weather set record high temperatures and provided above-average warmth for parts of the U.S. At the AccuWeather Global Headquarters in State College, Pa., for example, the temperature was 23°F higher than the normal high temperature for March 7.

"There have been some record highs reported today, especially in Pennsylvania and New York," said Edwards. "Dubois, Pa., set a record today, as did Watertown and Rochester, N.Y. We're seeing scattered record-high temperatures mainly across the mid-Atlantic and the Northeast."

Parts of Texas, Arkansas, Louisiana and Oklahoma will receive some rain and severe weather on Thursday.

Looking Ahead

Weekend temperatures are not expected to be as warm as the middle of this week.

"It will turn cooler for Friday into Saturday as another area of high pressure builds in behind that front," said Edwards. "But, temperatures will moderate again as we get into Sunday and early next week ahead of another storm."

While the weekend may be cooler, much of the U.S. will experience unseasonable warmth throughout next week.

"The opportunity for any kind of wintry precipitation is slowly dwindling," said Edwards. "In the near term, we don't really see any kind of winter weather on the horizon. After the brief cool temperatures this weekend, we'll see another warm snap next week."

Why Was It So Warm Wednesday

How Can Meteorologists Predict a Whole Season?

Mar 8, 2012; 3:09 PM ET

When AccuWeather.com releases its seasonal forecasts, people ask how meteorologists can predict the weather so far in advance. What are these long-range forecasts based on? A great deal of research.

Paul Pastelok, leader of the AccuWeather.com Long-Range Forecasting Team, said that the team forecasts a season after studying the complex interaction of current ocean, land and atmosphere conditions around the globe.

For weather enthusiasts, here's a list of some of the weather indices used by the AccuWeather team: ENSO, PNA, NAO, AO, PDO, MJO, ocean temperatures, soil temperatures and analog years.

La Niña and El Niño

The weather patterns across this fluid, ocean planet are highly interconnected. For example, Pacific Ocean temperatures (La Niña/El Niño) are a key factor in forecasting weather patterns.

"We look at past La Niña and El Niño seasons, looking at the strength and trend of those El Niños or La Niñas," Pastelok said.

A La Niña occurs when sea surface temperatures across the equatorial central and eastern Pacific are below normal. El Niño occurs when these sea surface temperatures are above normal. The greater these temperatures depart from normal, the stronger the La Niña or El Niño.

Both phenomena have a significant influence on the jet stream and overall weather patterns across the globe. While no two El Niños or La Niñas are exactly the same, general trends have been observed in the influence they have on the weather in the U.S. and elsewhere throughout the world.

Analog Years

Long-range forecasters also look for past years in which similar trends occurred. Meteorologists call these years "analog years". An analog year is a past year where there were similar temperatures in the ocean and pressures in the atmosphere to the current conditions.

"No year is ever the same, but you can get the general trends and patterns," Pastelok said.

Models are only part of the long-range forecasting recipe. Long-range forecasters also study recent trends in the weather, looking at temperature, rainfall, drought, snow cover and more. Trends can be recent months, year-to-date or even over many years.

"Models are projected in the future. But if they're not capturing what's going on now, they can't predict what will happen in the future properly," AccuWeather meteorologist Meghan Evans said.

How a Long-Range Forecast Can Bust

There are big risks when a forecaster makes a long-range forecast. The conditions of the atmosphere and the oceans constantly change. An example of a major oceanic change might be a sudden flip from La Niña to El Niño.

"[The oceans and the atmosphere are] not steady state," AccuWeather meteorologist Jim Andrews said. "If the changes are significant... then it can throw everything out of whack."

Non-events are also problems for long-range forecasters, like if a forecast blocking pattern doesn't happen.

"Either way," Andrews said, "you've hung your forecast on certain conditions and to have them happen or not happen can easily send the forecast astray."

Meteorologists can measure the accuracy of the long-range forecasts to see if it was good. Meteorologists gauge if temperatures were in fact above or below normal and whether precipitation and snowfall were above or below normal. General trends can be verified.

However, how people perceive the season often carries more weight than the numbers.

"It's so difficult because it boils down to perceptions," AccuWeather.com Expert Senior Meteorologist Bob Larson said.

For example, with winter, "you can predict a milder-than-average winter with less snow than average and have it verify," Larson said. "But if you have a big Thanksgiving snowstorm, a Christmas blizzard and a New Year's Eve ice storm, that's what people remember. They remember those big storms, not the weather in between, and think it was a terrible winter. Their minds drift to memorable events."

How Can Meteorologists Predict a Whole Season

 

Solar Flares May Bring Major Aurora, Minor Disruptions

(Image of an aurora borealis by Roman Krochuk/Photos.com)

Mar 8, 2012; 3:06 PM ET

A series of solar flares this week may yield additional episodes of the aurora borealis (Northern Lights).

Areal coverage of the displays produced by each coronal mass ejection are difficult to gauge ahead of time. The Northern Lights were visible over part of the Great Lakes region Wednesday night.

The best chance for viewing the show tonight, if the Earth's magnetosphere cooperates, will be in the northern Plains, part of the Midwest and much of the West.

There will be a nearly full moon tonight, which could detract from viewing the show somewhat. However, the display was still impressive last night, despite the full moon.

Experts at Space Weather.com state that not only do the magnetic storms unleashed by the flares cause the aurora borealis, but they can be somewhat disruptive.

The expanse of the Northern Lights and disruptions depend on whether or not the flare directly strikes the Earth versus a glancing blow, as well as the strength of the coronal mass ejection itself.

In the extreme case, there can be brief disruptions to radio and gps signals.

Space Weather indicates that a strong magnetic storm can cause satellite onboard computer systems to reboot.

As a precaution, some commercial flights will reroute their trips from polar regions.

 

Solar Flares May Bring Major Aurora, Minor Disruptions

Strong Storms Target Texas, Lower Mississippi Valley

Mar 8, 2012; 3:05 PM ET

Storms tonight have the potential to bring flash flooding, hail, frequent lightning strikes and locally damaging winds from central Texas to northern Mississippi and northwestern Alabama.

Motorists in the I-20, I-30 and I-40 corridors in the region can be hit with blinding downpours and excess water on the roadways. Flight delays are also possible.

While some of the rain is falling on needy drought areas, a large portion of the rain is falling on areas where ground moisture is high. This is why there is a risk of flash flooding in rural areas, as well as urban locations. Up to several inches of rain can fall, especially where the storms repeat.

As of the mid-afternoon, cloud cover over the warm sector of the storm area was greatly reducing the risk of the most violent storms.

Occasionally, severe thunderstorms, even in an average event, can produce a short-lived tornado.

Farther to the northeast over portions of the Ohio and Tennessee valleys, the risk of violent weather will pencil out. A tornado outbreak is not expected.

Drenching rain, flash flooding, locally gusty winds and thunder will occur in this area into the evening hours.

The zone of drenching rain and locally strong thunderstorms will shift southward later tonight and Friday, stretching from the Texas coast to the southern Appalachians and the North Carolina coast.

Strong Storms Target Texas, Lower Mississippi Valley