Wet, White, and Wild Weather

Surface map at 7:00 CDT April 18

This has been an interesting week for spring weather from the Rockies through the Midwest. In the last 24 hours there have been flooding rains, heavy snow, severe thunderstorms, and tornadoes, all related to the same weather system

Much of Colorado got more snow in the past 24 hours, with as much as 15 inches in south-central Colorado near Pueblo. Snow also accumulated 2 to 3 inches in western South Dakota and 2 to 4 inches in northern Minnesota. Snow also occurred in Nebraska and northwestern Kansas.

24 hour snowfall ending the morning of April 18

On the warm side of this system. severe weather was reported from Oklahoma to Indiana. Two tornadoes touched down in Oklahoma, baseball size hail pummeled locations in Missouri, and thunderstorm winds gusted to 90 mph in western Illinois.

The heavy rain produced by this weather system has caused flooding from the southeastern half of Iowa through northern Missouri and across the northern third of Illinois.

24 hour precipitation ending at 7:00 a.m. CDT April 18

Many rivers and streams are in flood, and record flooding is possible for some rivers in northern Illinois.  As of 10:00 a.m. CDT this morning 170 CoCoRaHS observers reported more than 4 inches of rain, and of those, 54 reported more than 5 inches of rain. Below are the highest rain amounts in the last 24 hours from CoCoRaHS observers.

CoCoRaHS reports for April 18, 2013

 It's not over, either.  More heavy rain is expected today ahead of the cold front as it sweeps through the Midwest, and severe weather is likely from Indiana eastward. Winter weather advisories are in effect from northern Kansas to Lake Superior and a winter storm warning is in effect for portions of Minnesota into northwestern Wisconsin and the Michigan U.P.

24-hour expected precipitation from 7am CDT 4/18 to 7am CDT 4/19

Watches, warnings, and advisories in effect aas of 10:00 a.m. April 18

The NeverEnding Winter

Snow depth the morning of April 16, 2013

Springtime warmth has made an appearance in parts of the eastern half of the nation, and April showers are rapidly turning the landscape from brown to green.  However, winter has kept an icy grip on an area from the Rockies through the Northern Plains to the upper Midwest. Late last week snow and ice fell from Nebraska to Wisconsin, and over the last few days more than a foot of snow has piled up in parts of Colorado and the Dakotas.

48 hour snowfall accumulation ending
the morning of April 16, 2013

The snow in the Dakotas resulted from a storm system that moved from Kansas and Nebraska northeast through Minnesota over the weekend. Ten to 16 inches of snow was reported from northern South Dakota through central North Dakota, with 3 to 6 inches of snow across northern Minnesota. In Bismarck, ND numerous records were shattered by this storm. On Sunday, April 14th Bismarck has 17.3 inches of snow, breaking the old record for that date of 5.0 inches set in 1986. It also set a new daily record for the month of April, breaking the old record of 15.2 inches on April 5, 1997. This was also the record snowfall for any calendar day of the year! The previous record was 15.5 inches on March 6, 1966. The storm total snowfall of 21.5 inches as of the morning of April 15 is a new record for April, topping the old record of 18.7 inches in April 1984.  A number of locations in North Dakota reported 20 or more inches of snow from this storm, with 22 inches reported by the CoCoRaHS observer in Center, ND (ND-OL-2)

The snow in Colorado yesterday was produced by another low moving across the Great Basin. This setup is ideal for snow along the Front Range. Easterly flow resulting from the low to the west and strong high pressure to the northeast forces the air to rise as it encounters the Rockies, condensing the moisture and producing precipitation.

Surface map for 2:00 a.m. EDT April 15, 2013

These storms often produce lots and lots of snow, and this system was no exception. A foot of snow and more fell across the Fort Collins, Co area, home to CoCoRaHS headquarters.

CoCoRaHS snowfall in Fort Collins, CO April 16

Snow in the Denver area ranged from around 4 inches east of the city to 12 to 24 inches in the higher terrain west of Denver, with 24.5 inches of snow reported by a CoCoRaHS observer in Golden (CO-JF-267).

CoCoRaHS snowfall for the Denver Metro area, April 16

And it isn't over yet.  The system that brought the snow to Colorado will be lifting out to the northeast, and winter storm warnings are in effect for portions of Wyoming, Nebraska, and South Dakota. Winter weather advisories are in effect for parts of Montana, Wyoming, Colorado, Utah, and Nevada.

Watches, warnings, and advisories effective 10:00 a.m. MDT April 16

If there is a silver lining to all of this it is that the moisture from these snows will certainly help provide some relief from the drought conditions that exist across the central and western U.S.
piled up in parts of Colorado and the Dakotas.

First Tornado Hook Echo Observed 60 Years Ago Today

Today thunderstorms and tornadoes are routinely tracked using weather radar, and in fact anyone with a computer or smart phone can pull up the latest radar images for their area.  As you might surmise, this wasn't always the case.  After World War II surplus radars were being used to study thunderstorms and precipitation. The Illinois State Water Survey, a state agency on the University of Illinois campus, was in the beginning years of a weather research program at the time, a program that continues today. It was during a project conducted by the Water Survey that the now classic "hook echo" radar signature radar was first discovered and photographed in detail. As with many scientific discoveries, it was a serendipitous event.

Meteorology building at Willard Airport and the radar used
to detect the hook echo.

In the late afternoon and early evening hours of April 9, 1953 scattered thunderstorms were moving eastward across central Illinois. At the University of Illinois Willard Airport located a few miles south of Champaign, the Illinois State Water Survey was operating a radar collecting rainfall data for a project to determine the utility of radar for the measurement of precipitation amounts. The radar was a modified 3-centimeter wavelength radar that had been used as an airborne surveillance system installed aboard U.S. Naval aircraft in World War II. A rain gauge network had been established in east-central Illinois to provide ground truth for the radar-indicated amounts.  That day, radar engineer Donald Staggs and an assistant were working at the radar. The radar was only operated as needed for this project, and the normal procedure was to turn off the radar after precipitation had passed through the rain gauge network.  However, on that afternoon Staggs noticed the peculiar radar echo with the thunderstorm and thought “I wonder if that might be a tornado.”  Ten minutes later he received a phone call from a woman who lived just north of Champaign.  She wanted to know if he was seeing "the twister that just destroyed my barn" on radar. At that point he knew that the hook echo might just indicate a tornado and kept tracking it and photographing the radar display as the storm moved into Indiana.  This distinct tornado echo, which was observed near the southwest edge of the associated thunderstorm, contained the tornado funnel.

The first hook echo identified and photographed on radar.

Although Staggs recognized the unusual nature of the radar echo and the possibility of a tornado, positive identification was not made at the time of the radar tracking.  Only when the radar film was developed the next day did the scientists realize that the distinctive hook echo was the signature of the tornado reported the afternoon before.  Field surveys confirmed the tornado, which was eventually rated an F3.

The tornado moved east and dissipated just over the Indiana state line. It had a path of about 54 miles, and destroyed eight homes and damaged 72 others. There was one fatality in Vermilion County, Illinois from the storm.

A view of the tornado on April 9, 1953 taken from near Royal, Illinois.
Tornado photograph taken by Ernie Kienietz, provided by Scott C. Truett

The original report on this historic event is available online, and contains a description of the weather conditions that day, information on the weather radar, and the results of the field survey of the tornado damage, including photographs.  It's a fascinating piece of weather history.  You can read it at the following link.

Study of an Illinois Tornado Using Radar, Synoptic Weather and Field Survey Data, Illinois State Water Survey Report of Investigation 22, Urbana, IL by F.A. Huff, H.W. Hiser, and S.G. Bigler. 1954 

In the report's conclusion, the authors of the report speculated that with more collection of tornado radar data, "...it may be possible to establish radar storm warning systems in tornado areas to reduce loss of lives, and to some extent property damage."  This discovery did, in fact, launch a national research program aimed at tornado detection by radar.  In 1962 the National Severe Storms Laboratory was formed out of the National Severe Storms Project, conducting research on the detection of storms with radar. Today, there are 164 weather radar sites across the U.S. that scan the skies 24/7.

Every Home Should Have a Weather Radio

Trained meteorologists can forecast the development of severe weather. The latest weather radar technology can detect the signatures and features that signal the formation of severe storms and tornadoes. Warnings are issued as soon as the threat is evident. 

How do you and your family receive the warnings that are issued? If there is a tornado warning your community may use sirens to alert those who are outdoors (sirens are NOT meant to warn people indoors). You may hear it if you are near a radio or television. If you are inside with the windows closed and music playing, for example, how will you know?  If it is in the middle of the night and you are sound asleep, how will you know about the warning?

The answer is a weather alert radio. Just like every home should have smoke detector, every home and business should have a weather alert radio.

In the aftermath of storms we often see people interviewed who say "It struck without warning". What that statement usually means is "I wasn't aware of a warning", because in most cases a warning was not only issued, but issued with enough time to take shelter.  Everything from the forecast to the warning can be perfect, but if people aren't receiving the information then that information can't help them.

There are over 1,000 weather radio transmitters in all 50 states. Most of the time the programming is routine forecasts and information. When the weather turns severe, however, the weather radio is your direct line to the latest storm information.  About ten years ago the NWS Weather Radio network became part of the Emergency Alert System (EAS) managed by the Federal Communications System. With this capability the public can be alerted to information about natural disasters (such as earthquakes), civil emergencies, toxic and chemical spills, and child abduction Amber alerts in addition to the weather watches, warnings, and advisories.

Weather radios come in portable models that you can take with you to outdoor events or other activities like hiking or camping. Some have crank and/or solar recharging capabilities. Desk models run on AC power with battery backup.  The prices of radios range from $25 to $135, with most desk models in the $40 to $75 range. One feature you should seriously consider is a radio with SAME (Specific Area Message Encoding) capability.  This allows users to receive messages only for their designated county or counties of interest rather than the entire broadcast area. This is especially nice at night, as your radio alert will not be activated for areas you have not selected. On the basic radios without SAME any alert issued for any area covered by a specific transmitter will be triggered on the radio.

There are only seven VHF frequencies used for NOAA Weather Radio transmissions.

NOAA Weather Radio frequencies in the U.S.

The NWS has a map page that allows you to access information about all U.S. stations and coverage areas.

NOAA Weather Radio coverage map for Oklahoma

The map interface will also let you view includes a county by county listing of weather radio stations in each state and their current status.

NOAA Weather Radio station status for Illinois counties

NOAA also has a web page with consumer information, including a list of resellers of weather radios. 

Weather radio receivers will also work in Canada. Environment Canada, the government agency responsible for producing official forecasts, operates a network of "Weatheradio" transmitters which generally operate on the same frequencies as the U.S. NOAA Weather Radio network. More information on weather radio in Canada can be found here.

It's worth repeating - every home should have a weather alert radio.

2013 Thunderstorm Season - "Impact Based" Tornado Warnings Experiment

The NWS Central Region states and offices participating

April 1st marks the start of the thunderstorm season in the central U.S. This year 38 National Weather Service offices in 14 states that comprise the NWS Central Region will be issuing tornado warnings using enhanced messaging to emphasize the particular nature and danger of a storm. These "impact based warnings" (IBW) are an experiment to better communicate the expected impact and damage from a tornado in order to provide additional information to the media and emergency managers and better motivate people to take appropriate action.

This experiment was developed after an assessment of the May 2011 tornado that devastated Joplin, Missouri killing 158 people. There were three key findings from this assessment:

• The majority of people identified local outdoor warning systems as their first source of warning.
• The majority of people sought confirmation from additional sources before seeking shelter.
• Credible, extraordinary risk signals prompt people to take protective actions. 

A number of "tornado tags" will be utilized for tornado.  Two tags will indicate whether the tornado was detected by radar or observed by spotters or law enforcement. Damage threat tags will be used to convey the level of damage expected from a particular storm.  Warnings will include the particular hazard (tornado, hail), the source of the information (spotter confirmation, on-going damage), and the impact and type of damage expected.

The IBW tags allow the forecasters to distinguish between a low-impact event (for example a weak, short-lived tornado) and a high impact event (a large, long-lived tornado)  Large, damaging tornadoes are relatively infrequent, so most of us will never hear a warning for a tornado causing considerable or significant damage.

In 2012 NWS offices in Kansas and Missouri utilized the impact based warnings. Below is a warning issued last year using the enhanced wording. The changes from a "standard" warning are highlighted in red.

Tornado warning issued on April 14, 2012 for central Kansas.

At the conclusion of this storm season the IBW experiment will be independently evaluated to determine its effectiveness.

Will changes in wording actually make a difference? This is an experiment to find out. Public response to warnings is a complicated issue and something that the NWS and emergency officials have wrestled with for years. How the information is communicated (sirens, the broadcast media, the Internet) and the content of the message that is being communicated are two sides of the same coin.

You can read more about the Impact Based Warnings experimental product at this NWS Central Region page.

More background on what was learned from the 2011 Joplin tornado can be found at NWS Central Region Service Assessment Joplin, Missouri, Tornado–May 22, 2011 

New Look For Storm Prediction Center Web Site

The NWS Storm Prediction Center (SPC) launched it's new home page today, sporting a sharp new look and quick, easy access to SPC products. SPC is responsible for forecasts and watches for severe thunderstorms and tornadoes over the contiguous United States. The SPC also monitors heavy rain, heavy snow, and fire weather events across the U.S. and issues specific products for those hazards.

The Overview map with the tabs across the top remains the centerpiece of the page but is off on the left side. On the right side a window contains thumbnails and links to all SPC graphical outlook products. Tabs on this window can be used to view the convective outlooks, current watches, mesoscale discussions, and fire weather outlooks. On the bottom half of the page are windows to severe weather climatology, public awareness and education material, case studies, and publications. Gone is the long menu list on the left hand side of the page that still is a feature of most NWS web pages.

The pages behind the home page still utilize the old web page design so you will still have to deal with the old menu structure until these are changed.  However, the home page provides users with a clean "at a glance" overview and access to severe weather information.

One Good Thing About Spring Snow

It's March 25th and the weather headlines look like they should be dated December 25th. Ground zero for Day 3 of this storm was an area from east-central Missouri through central Illinois. There was an initial burst of snow early Sunday morning that left up to 3 inches of snow in some locations, followed by several hours of no precipitation. In many areas the snow that fell overnight melted off as temperatures rose to the mid-30s. By late morning and early afternoon Sunday heavy snow was quickly spreading eastward across Illinois.

The Mesoscale Convective Discussion graphic at
11:52 a.m. CDT March 24 from the Storm Prediction Center

The atmospheric conditions were set up for a sustained heavy snow event. Low pressure was moving slowly eastward though southern Missouri, and warm, moist air aloft was streaming northward. This  combined with instability and strong upward motion in the atmosphere to produce the heavy snow. Thundersnow was reported at a number of locations from St. Louis into central Illinois. Snowfall rates of 2 to 2.5 inches per hour occurred over a sustained period, and the result was widespread snowfall of 8 to 12 inches, with a number locations west and northwest of Springfield, IL reporting 15 to 18 inches of snow. The CoCoRaHS Observer at IL-SG-17 (Springfield 4.4 W) reported 16.5 inches of snow. This was a heavy wet snow, with snow-to-water ratios on the order of 9 to 1 (9 inches of snow to one inch of water).

48 hour snowfall accumulation map through 7:00 a.m. March 25 for central Illnois

Snow from this system also piled up from Indiana through southern Ohio and northern Kentucky to West Virginia. The storm still has a little punch left tonight, with Winter Storm Warnings in effect for the central Appalachians.

72 hour snowfall accumulation through 7:00 a.m. March 25

There is one good thing about a late spring snow, especially if you are tired of it. The higher March sun and temperatures above freezing quickly melt the snow on pavement reduce the snowpack. By late afternoon today where I live roads were mostly dry and you could tell that there already was a significant reduction in the depth of snow on the ground from the 10 inches I measured this morning.The hazard the next couple of nights will be refreezing of melting snow on roads as temperatures drop into the 20s overnight.

Major Storm Continues Slow March East

A spring storm that already has dumped more than 12 inches of snow on eastern Colorado and another 4 to 8 inches in eastern Kansas and western Missouri will continue to affect the central and eastern portions of the country through Monday.

48-hour snow accumulation ending the morning of March 24.           

Surface weather map at 10:00 a.m. CDT March 24

As of mid-morning the center of the sprawling low pressure system was located over the lower Ohio and Tennessee Valleys.  Snow was falling from Missouri east through Illinois and north into Iowa. The system is being fed by an ample supply of moisture from the Gulf of Mexico, and that combined with the strong upper level system is producing heavy snow from eastern Missouri through central Illinois. CoCoRaHS observers have reported snowfall rates of 2 inches per hour.  There is a possibility for thundersnow in the southern portion of the heavy snow band.

Snow accumulations will be heavy with this storm. There is a high probability of 4 inches or more from central Missouri to western Virginia, and a good chance of 8 inches or more within this band.from eastern Missouri into southern Indiana, as well as in the mountains in western Virginia.  As of  1:45 pm CDT today 6 to 8 inches has already accumulated in west-central and central Illinois with heavy snow still falling.

24-hour probability of 4 inches or more of snow (left) and 8 inches or more of snow (right)

Winter storm warnings are in effect from Missouri eastward into Pennsylvania and eastern West Virgina.

Watches, warnings, and advisories as of 2:00 p.m. CDT March 24

Cooler, drier air plunging south in the wake of this system has raised the fire danger in southern Texas and red flag warnings are in effect today, Freeze warnings are in effect for northeastern Texas and northwestern Louisiana tonight.

Three Weeks Into Spring

Illumination of the Earth by the Sun
at the March equinox, as seen from the Sun.

The vernal equinox was at 6:02 AM CDT this morning, marking the start of astronomical spring. The minutes of sunlight will be increasing each day until the summer solstice on June 21st. As we all know, spring is the transition between the coldest period of the year (winter) and the warmest (summer). For those of us in the weather and climate field, spring actually started on March 1st and will continue through May 31st. Why do we use the calendar seasons instead of the the astronomical seasons?  Generally it is much easier to compute averages and other statistics for a fixed number of days. The occurrences of the solstices and equinoxes can vary by a day or so each year making the seasons different lengths. And, it turns out that the meteorological seasons are closer to reality in general.. A study done in 1983 by a researcher at the University of Illinois (now with the National Center for Atmospheric Research) found that, for the mid-latitudes of North America, the seasons (in terms of temperature) more closely follow the calendar than the astronomical events.  In fact, the astronomical seasons are only appropriate over the oceanic areas of the Southern Hemisphere. The response of the atmosphere to solar radiation lags by about 27 1/2 days at mid-latitudes. This means that during summer, for example, the peak heating would tend to occur during mid-July, 27 1/2 days after the summer solstice.  Defining summer as June 1 to August 31 makes sense since mid-July is the midpoint of the meteorological summer (June, July, August). However, the calendar alignment isn't perfect for a number of reasons. For example, if we were to base the seasons in the Northern Hemisphere strictly on mean temperature, spring would be the period from March 9 to June 8. 

March 1st or March 20th - this year some will argue, with good reason, that spring still isn't here!

If you have an interest in the astronomical you will find the U.S. Naval Observatory (USNO) web site a wealth of information. The USNO serves as the official standard of time for the entire United States. You can determine sunrise or sunset for any location in the country or find out when the phases of the moon will occur at any point in the future, or get the dates and times of the equinoxes and solstices. The Sky This Week describes what planets can be viewed and what other astronomical phenomena can be observed.

Trenberth, Kevin E., 1983: What Are the Seasons? Bulletin of the American Meteorological Society, Vol. 64, No. 11, pp. 1276-1282.

Ol' Man Winter Just Won't Let Go

Here we are, almost three weeks into meteorological spring and much of the country is dealing with below normal temperatures and winter precipitation. Winter Storm Warnings are in effect from eastern New York through much of New England, and warnings and advisories are also in effect in the lee of the Great Lakes.

Warnings, watches, and advisories as of 1:00 p.m. EDT March 19.

The reason for this is a double-barreled low pressure system. The main center was located near the eastern end of Lake Superior while a secondary low was located just south of Long Island, NY.

Surface weather map as of 11:00 a.m. EDT March 19

CoCoRaHS new snowfall map for March 19

Snowfall amounts from 6 inches to more than a foot are possible in the warned areas of New England. As of this morning 6 to 10 inches of new snow had accumulated from southern Vermont and New Hampshire into eastern Massachusetts. The snow will continue to progress northward today and some of the highest storm totals are likely over Maine. With temperatures hovering near freezing this is one of those pain-in-the-back storms with heavy, wet snow. 





Snow also blanketed northern Minnesota, much of Wisconsin, and the Michigan Upper Peninsula yesterday and last night. Snow continues today on the downwind side of the lakes.

24 hour snowfall ending the morning of March 19 in the upper Midwest

It's likely that winter will hang on for most of March. The latest 6 to 10 day outlook from the Climate Prediction Center which takes us through March 28 depicts a very high probability of colder than normal weather for the eastern one-half to two-thirds U.S.  This is quite a contrast with the record warm March of 2012, and it is the type of thing that makes meteorology such a fascinating field.

CoCoRaHS observers will need to keep those snowboards out just a little longer.

SnowNews is Good News

Snow Water Equivalent map for the central Rockies

Despite what your own feelings about snow may be, there is no question that winter snow in the western United States does more than provide scenic landscapes or downhill runs for skiers. The snow that piles up in the mountains of the western U.S. during the winter provides 50 to 80 percent of the annual water supply used for drinking, irrigation for agriculture, and water needed to maintain flows in rivers and streams for power generation.

The snow that falls each autumn through early spring eventually melts as the weather warms, and the runoff from the snow melt is captured in lakes and reservoirs or flows through streams and tributaries into major rivers such as the Colorado and Columbia. In order to be able to successfully manage this resource water managers need to have information on how much snow has accumulated, where it has accumulated, and most importantly the water content of the snow. Since the 1930s the Natural Resource Conservation Service (NRCS) of the U.S. Department of Agriculture has coordinated the Federal, state, and private efforts to measure and evaluate the snowpack in the western U.S.

If you think measuring the water content of 15 inches of snow with a CoCoRaHS gauge is difficult, measuring mountain snow tens of feet deep and its water content is a whole other ballgame. It takes specialized equipment, skills, and training to conduct these snow surveys. The monitoring of the mountain snow made strides in the late 1970s when the first SNOTEL (for snow telemetry) stations were put into operation. There are currently more than 730 SNOTEL sites in 11 states, including Alaska, that collect and transmit data in near real-time to a central computer in Portland, Oregon. Most are located in areas that are difficult to access.

A SNOTEL site in Truckee, California

The NRCS National Water and Climate Center and the Snow Survey and Water Supply Forecasting Program publish a quarterly newsletter called SnowNews. It's not just about snow, but there is plenty of snow-related content. It is a comprehensive newsletter that addresses water and climate related topics that impact all resource managers and stakeholders (e.g. commercial, government, tribal, non-government organizations).  It has the latest news on web-related resources, what’s happening within NRCS water supply monitoring networks (SNOTEL covering the western states and SCAN, the Soil Climate Analysis Network, covering the nation). The just-released Spring 2013 issue features an article on the implications of the current drought in much of the U.S. and the seasonal water supply forecast for the western United States.

You can learn more about the importance of snow in the west and how this critical resource is monitored in Snow Surveys and Water Supply Forecasting.

What a Difference a Year Makes

Last March at this time we were approaching the end of the first half of the warmest March on record in the contiguous U.S.  This year, things are quite different through the first 10 days of March.

At this time last March the warmest part of the month, especially in the central U.S., lie just ahead. The highest number of temperature records occurred between March 14 and March 24, 2012. Maximum temperature and high minimum temperature records were not just broken - they were shattered by 10 and 20 degrees or more. By the end of March 2012 were more than 15,000 daily records for warmth broken across the country. So far in March 2013 there have only been 374 warm temperature records set.

A "Weather Active" March Weekend

CoCoRaHS observers across much of the country will be busy measuring precipitation of one kind or another this weekend.

Western Atlantic surface map, 7:00 EST March 7

Those in southern New England are still dealing with the storm the moved off into the Atlantic late yesterday. This storm has intensified and stalled out over the Atlantic east of Virginia.  A sharp ridge of high pressure to the east of this storm, and another intense low to the east of the high are blocking the eastward progression of this system. Strong easterly winds are pumping a steady supply of moisture into southern New England, much of which is falling as snow. Snow amounts from 6 to 12 inches are forecast across southern New England. This is a wet snow, and the weight of the snow combined with the high winds means that power outages will be likely. In addition, the winds are pushing the water toward coastal areas, and coastal flood warnings are in effect from Rhode Island to Maine through tomorrow morning.

In the west an upper level system will come ashore in southern California early Friday heading toward the southern Rockies. Rain and snow will accompany this system as it makes its way across the Southwest, and winter weather advisories, watches, and warnings are in effect for a number of western states. This southern system will merge with another disturbance in the Northern Plains, and by Saturday morning will be bringing snow to a large portion of the central and southern Rockies and the Northern Plains. Ahead of this system, strong southerly winds will feed moisture to fuel showers and thunderstorms eastward through the Midwest.

Quantitative Precipitation Forecast (QPF) from 7:00 p.m. EST March 7 to 7:00 p.m. March 10.

A March Lion

Surface weather map at 7:00 p.m. EST March 6

The storm currently moving out to sea off the Virginia coast affected a large portion of the country this week. Tonight storm warnings are in effect offshore and gale warnings are in effect for Chesapeake Bay, Delaware Bay, and Long Island Sound. Coastal flood warnings are in effect for southern Virginia, Delaware, and the southern two-thirds of New Jersey as strong easterly winds gusting to 60 mph push water inland.

On Tuesday heavy snow fell in the Midwest, and overnight the snow shifted to the Appalachians. Snowfall reached 18 to 24 inches in the mountains of Virginia today with amounts tapering off toward the coast. The Washington DC metro area dodged a bullet, with only an inch or two of snow.

We're not done with this storm yet. The precipitation with this system will be spreading into southern New England tonight and Thursday, with some snow and rain hanging around through Friday. Heavy snow is possible at times Thursday from the Adirondacks to the southern New England coast.

Forecast map for Friday, March 8

Don't Put Away Those Snowboards Yet

24 hour snow fall

A storm that moved from the Pacific into British Columbia on Saturday will be affecting the eastern half of the U.S. the next two days. It has already brought widespread snow to the Canadian Rockies, Montana, and the Dakotas with amounts from 12 to 18 inches.  This evening the low pressure center was just south of Fargo, North Dakota, and by Tuesday evening the low is expected to be in the Ohio Valley. At rush hour on Wednesday the morning the storm should be located near Norfolk, Virginia.  Winter storm warnings and winter weather advisories are in effect from the Dakotas to the mid-Atlantic coast.

Watches, warnings, and advisories in effect at 10:00 p.m. CST

Heavy snow will be the main feature of this storm, but freezing rain and sleet will be causing problems along the southern periphery of the storm track,

Probability of 4 or more inches of snow for the period from 6:00 p.m. CST March 4 to 6:00 p.m. March 5 (left), and from 6:00 p.m. CST March 5 to 6:00 p.m. CST March 6 (right).