Tuesday, April 22, 2014

News from the (Lack of) Severe Weather World

NOAA's Storm Prediction Center has launched a new experimental web page for viewing storm reports.  You may be used to seeing this map of storm reports:

Storm reports for the tornado outbreak in April 2011.
In the current map and report format certain parts of the Local Storm Reports (LSRs) are truncated or ignored for the sake of brevity. The reports are listed below the map on the page.

The new, experimental system contains more information by retaining more from the listing of the report, including the source of the report, extending the remarks section to include all 500 characters, and whether the report magnitude was measured, estimated, or unknown. Also, will include LSRs related to winter weather.The map is larger and easier to read.

Experimental storm report map for the tornado outbreak in April 2011

New winter weather storm report map
One of the biggest differences between the current Storm Reports page and the new experimental page is the interactivity and the amount of information available.  Users can display subsets of reports  and can overlay counties, highways, NWS County Warning Areas (CWAs), and other features.

Tabs at the top of the map allow you to display all reports, or just tornado reports. The individual reports are listed below the map.

 Clicking on the "+" icon on the far left expands the report to show the detail. Additional detail can be seen by selecting the Map option on the far right.

SPC is seeking feedback on the experimental map, so feel free to put it through its paces and provide comments or suggestions. A link to provide comments is at the top of the page.

So far there hasn't been much to look at related to severe weather this season. The Storm Prediction Center says that 2014 tornado activity through April 21 is estimated to be at a record low level.  Through today there have been 85 severe thunderstorm watches and 84 tornado watches issued. In 2013 the corresponding numbers were 136 and 136. In 2011, when 465 EF-1+ tornadoes had been counted by this time there had been 184 tornado watches issued through April 22.

 It's hard to say if or when our luck will hold out. The system forecast to move across the country later this week is likely to produce severe weather from the Central and Southern Plains east through the lower Mississippi River Valley over the weekend. Stay up-to-date on the weather at your local National Weather Service office web page or at the Storm prediction Center web site.

Outlook outlining at a 30% or higher probability for severe thunderstorms within 25 miles of any point
for Saturday, April 26 (D5) and Sunday, April 27 (D6).

Tuesday, April 15, 2014

Winter Won't Let Go

Spring 2014 has been a roller coaster ride for much of the country. The month of March was a cold one east of the Rockies, and nationally was the 43rd coldest March on record and the coldest since 2002.  The first two weeks of April have held a little more promise, teasing us with brief periods of warm weather. The latest "bait and switch" occurred this past seven days. There was a nice warm-up this weekend as a developing low over the Central Plains combined with a high pressure system along the east coast produced strong southerly winds and boosted temperatures into the 70s and even low 80s as far north Chicago. Temperatures were a summer-like mid 80s in the Central Plains. Lincoln, Nebraska reachd 85°F on Saturday, one degree short of the record for April 12.

Surface temperatures at 4:00 p.m. CDT Saturday, April 12

24 hours later it was in the 30s and snowing. This morning Lincoln reached a  morning low of 19°F shattering the old record of 24°F.

Surface temperatures at 7:00 a.m. CDT Tuesday, April 15
While central portions of the country were enjoying warm weather snow was falling in the Rockies from Montana through Wyoming and Colorado into New Mexico as the low continued to organize over the Plains. By Sunday the system was pressing eastward, with rain changing to snow in the Arctic air behind the front.

Surface map at 1:00 p.m. CDT on Sunday, April 13.
Snow fell from Nebraska through much of Iowa, central and southern Wisconsin, and the Michigan U.P. Snow amounts ranged from 4 to 8 inches in Wisconsin and Michigan. On Monday light snow fell across northern and central Illinois, northern Indiana, lower Michigan and Ohio.

72-hour snowfall ending Tuesday morning, April 15.
As the front pushed through the Gulf States it kicked off severe thunderstorms across eastern Texas, northern Louisiana and central Mississippi. Further south, heavy rain fell from Mobile, Alabama east into the Florida Panhandle. Three to more than four inch amounts were common, but just east of Mobile Bay rainfall ranged from six to more than inches. Two CoCoRaHS observers north of Fairhope, AL reported 9.19 and 9.79 inches of rain this morning.

CoCoRaHS precipitation amounts in southern Mississippi, Alabama, and the western Florida Panhandle for the 24 hour period ending the morning of April 15.

Freeze warnings are in effect for much of the southeastern United overnight, and Winter Storm Warnings and Winter Weather Advisories extend from central Minnesota across northern Wisconsin and the Michigan U.P .through Thursday morning. Up to a foot of snow is possible across northern Wisconsin into the western U.P.

Watches, warnings and advisories as of 11:30 p.m. CDT April 15
This was probably winter's last gasp in the Plains and Midwest, but the northern Great Lakes and northern New England could see more snow this weekend.

Tuesday, April 8, 2014

CoCoRaHS Observations Served Up on NWS Web Sites

CoCoRaHS observations are now accessible through an interface on National Weather Service office web sites.  The observations are available using a tool called NOWData (NOAA Online Weather Data) found under the Local Climate option on the web site menus.

The main left-hand menu on the NWS office home page (top), and the window showing the NOWData tab (bottom)

NOWdata has been a feature on NWS climate pages for a couple of years, but a recent upgrade added new capabilities and access to CoCoRaHS observations, data from Remote Automated Weather System (RAWS) network, data from the USDA SNOTEL network, as well as from the NWS U.S. Cooperative Network stations. RAWS stations are largely used in the western U.S. for fire weather support, so your area may not have nay RAWS stations nearby depending on where you are.

If you would like to look at data from the U.S Cooperative Network stations, choose a station from the list in the list box on the left-hand side.

NOWData menu for the NWS Lincoln, IL office

CoCoRaHS and RAWS data are only accessible through the map interface. To access the map, click the View Map button on the left-hand side of the window.  The initial map that displays will show the NWS County Warning Area (CWA) shaded with push pin symbols representing the U.S. Cooperative Network stations. If you hold your mouse over a symbol on the map the name of the station will display in the lower left corner of the map window.

To view the CoCoRaHS stations available (stations that have reported in the past year), click the "Show more stations" button at the bottom of the window.  The map will get cluttered, but you will see the CoCoRaHS symbols on the map. You can zoom in on an area by dragging/panning the area you are interested in to the middle of the window, then click on the "+" symbol as many times as needed to zoom into the area you want, or you can use your mouse wheel. Again, holding your mouse over a symbol will display it's name in the lower left hand corner of the screen. Click on a symbol to select that station.

The NOWData map window displaying U.S. Coop an CoCoRaHS stations

The data is available in tables and in charts. Since we don't record temperature as part of CoCoRaHS none of the temperature products will be relevant.  here are examples of the products using data from my CoCoRaHS station, IL-CP-1.

Daily data for a month is similar to the Station Precip Summary on the CocoRaHS web site.

Daily precipitation for the current month. You can list daily precipitation for any month in the record.

The Daily Almanac provides you with your statistics for today and the month and year to date, as well as record highest and lowest amounts and accumulations.

Daily Almanac product on NOWData

Monthly and annual summary product on NOWData.
Monthly Summarized Data is also useful. With this you can view your monthly totals, the daily maximum or minimum for each month, the mean monthly precipitation, and the number of days where precipitation is equal to a great than an amount you specify. However, one serious drawback to the monthly summarized data is that it does not currently include multi-day amounts.  When I first pulled up my data I was amazed at the number of "M"s (missing) appeared in the monthly totals. If data is missing for any day in the month, then the sum is set to missing, and if any month is missing, the annual total is set to missing. I do not have any days missing in my CoCoRaHS record. However, I have a number of multi-day accumulations, as many of us do. The underlying database for the NOWData tool does not at this time assimilate the multi-day amounts, so days included in a multi-day period are set to "M". I've been told that this should be resolved in the future. In the meantime, your can use the Station Precip Summary option on the CoCoRaHS web site to get your actual monthly totals.

Accumulation graphs can also be generated for a time period you specify. The graphs display the highest, lowest, and the actual data for the period you specify.  When you mouse over a data point on one of the lines in the chart it will display the data, observed precip, accumulation to date, and the highest and lowest accumulation for the period to date for the station selected.

Accumulated precipitation for 2014 for my CoCoRaHS station.

Accumulated snow fall for my station for the winter of 2013-2014.

Take some time to jump on to your NWS office web site and play around with NOWData. It's a pretty cool tool. Here is a link to a page which lists and links to all of the NWS offices by state:

NOWData - NOAA Online Weather Data

Thursday, April 3, 2014

40th Anniversary of the April 3-4, 1974 Super Outbreak

In a little under 18 hours from April 3 to the early morning hours of April 4, 1974 the central and eastern U.S. experienced a historic damaging and deadly tornado outbreak. 148 tornadoes left a path of destruction across 13 states from eastern Missouri through Illinois, Indiana, Kentucky, Ohio, Alabama, and North Carolina, South Carolina, Michigan, Mississippi, and West Virginia.The storms were most numerous and the damage concentrated in Alabama, Georgia, Tennessee, Kentucky, Indiana, and Ohio.The storms resulted in 330 tornado-related deaths, 5,484 injuries, and $600 million in damages. The outbreak produced an astounding seven F5 tornadoes and 23 F4 tornadoes. The 1974 Super Outbreak occurred in a time before Doppler radar and well before the Internet and it's ability to rapidly and widely disseminate information. NOAA Weather radio was in its early stages of deployment.

On April 3, 1974 the early morning weather map depicted a strong low pressure system in central Kansas with a cold front trailing south into eastern Texas. and a warm front extending east from the cold front through Arkansas Tennessee, and North Carolina. South of the front warm, humid Gulf air was in place. A line of early morning thunderstorms were moving through eastern Missouri and western Illinois. Northwest of the low pressure center snow was falling in western Kansas, eastern Colorado, and southern Nebraska.

Portion of surface weather map for 7:00 a.m. CDT, April 3, 1974

Forecasters at the National Severe Storms Forecast Center (now the Storm Prediction Center) saw the potential for severe weather the day before and had notified Weather Services Offices  to be ready. However, the extent and intensity of the severe weather was still uncertain. By the morning of April 3 the potential for severe weather was coming into better focus. The first Severe Thunderstorm Watch was issued at 8:27 a.m. CDT for the Ohio Valley, and over the next 19 hours 28 severe weather watches were issued covering almost the entire area from the Gulf of Mexico to the Canadian border and from the Mississippi River to the East Coast.

Map of the tornado tracks for April 3-4, 1974
prepared by Dr. Ted Fujita
It was early afternoon when the severe weather development became explosive. A severe thunderstorm hit St. Louis at about 1:05 pm CDT. This storm, which had high winds and 2.75 in hail (baseball-size) caused 25 injuries and $45 million in damage, a record hail loss at the time.  A lot of the hail hit in the part of the city were the were a number of car dealerships, and cars in the lots were decimated by the hail.

The first tornado of the outbreak touched down in Morris, IL (Grundy County). It was a weak (F0) tornado that was on the ground for only a tenth of a mile. An hour later two more tornadoes touched down in central Illinois, quickly followed by more tornadoes in Illinois and Indiana. Storms spawned tornadoes throughout the afternoon and evening at a rapid pace.  At one point a total of 15 tornadoes were on the ground at the same time, and meteorologists in Indiana placed the entire state under a tornado warning. This was the first and only time in U.S. history that an entire state was under a tornado warning.

The F5 tornado as hit hit downtown Xenia, OH.
Photo by Kitty Marchant
The deadliest tornado to occur was the F5 tornado that destroyed much of Xenia, Ohio. 32 people were killed and 1,150 were injured. Almost half the buildings in Xenia were damaged or destroyed, and damages were in excess of $100 million (1974 dollars) About the time the Xenia tornado developed near Bellbrook, OH, another tornado touched down in Breckinridge County, KY and quickly intensified to produce F5 damage as it plowed through Brandenburg KY. As the afternoon wore on and the atmosphere became more unstable thunderstorm supercells developed eastward through the Southeast U.S.

Depiction of the upper level conditions (left) and surface conditions (righ)t at 7:00 p.m. CDT on April 3, 1974

There is no way to thoroughly write about all that occurred on the 18 hour period in April 1974 in a blog post.  It was a much-researched and documented event. You can easily spend many hours reading through the huge amount of information available on the 1974 Super Outbreak.  The Super Outbreak led to significant changes in warning procedures for severe weather.  Many communities that did not have outdoor warning sirens did so in the aftermath of the Super Outbreak. NOAA's Weather Radio network rapidly expanded in the wake of the Super Outbreak so that warnings could be quickly disseminated. It also helped spur the National Weather Service modernization program.

This short documentary on the Super Outbreak provides an overview of just what forecasters and the public were up against that day. This shows actual footage of tornadoes as they struck Xenia, Cincinnati, and Louisville, causing massive damage and numerous deaths. Includes discussion of advance tornado preparation and emergency coordination.   Courtesy of the National Archives.

Here are some sources for further reading. Many of these include numerous photographs, news accounts, and first-hand accounts of the events of that day. Several of the NWS pages contain links to other data and information about the Super Outbreak

NOAA Natural Disaster Survey Report - December 1974

NWS Nashville, TN - April 3-4, 1974 Super Outbreak

NWS Louisville, KY - 40th Anniversary of the April 3, 1974 Super Outbreak

NWS Wilmington, OH - The Super Outbreak of April 3-4, 1974

NWS Huntsville, AL - Remembering the April 3-4, 1974, Tornado Outbreak

NWS Birmingham, AL - The April 3rd and 4th 1974 Tornado Outbreak in Alabama

NWS Lincoln, IL - April 3-4, 1974 "Super Outbreak" of Tornadoes:  Impacts on Illinois

NWS Indianapolis, IN - April 3, 1974 Super Outbreak

Tuesday, March 25, 2014

The First Tornado Warning - Skill, Serendipity, and a Little Luck

On March 25, 1948, Air Force weather forecasters at Tinker AFB in Oklahoma issued the first ever tornado forecast (i.e. a warning).  A tornado swept through Tinker AFB during the early evening hours and caused millions of dollars of damage to aircraft, buildings, and other equipment. There were no injuries reported.

Remember, in 1948 weather forecasting was still in its infancy, especially compared to where we are today. There were no computer models or satellites, and the first tornado detected by radar didn't happen until five years later. The successful forecast of a tornado on this day was a mix of serendipity, luck, and the skill of two Air Force forecasters, Capt. Robert C. Miller and Major Ernest Fawbush.

Aircraft damaged at Tinker AFB by March 20 tornado.
Just five days earlier, on March 20, 1948, another tornado had struck Tinker AFB causing about $100million in damages, mostly to aircraft that were left out in the open. Following this storm, an official inquiry was conducted and as a result the Air Force directed that a tornado forecasting program be developed,and Fawbush and Miller were assigned the task of developing methods to forecast severe weather, especially tornadoes. The Air Force took the lead on severe weather forecasting because at the time the U.S. Weather Bureau had a policy against using the word "tornado" in a forecast. They feared panicking the public.

Fawbush and Miller began to study surface and upper air charts to look for conditions associated with severe weather.  Remember, this was well before computers - all the charts were all hand plotted and hand-analyzed. Obviously, their research couldn't have progressed very far in just a few days. However, Fawbush and Miller noticed that the weather conditions forecast for March 25th were very similar to those on March 20th. They notified the base commander General F. S. Borum. With the support and urging of Borum, they issued a severe weather and tornado forecast. That, in turn activated the new severe weather plan. Aircraft were moved to hangars, loose objects tied down, and personnel prepared to move to safe areas. By mid-afternoon afternoon of March 25th a line of storms developed southwest of Tinker AFB. At 3:00 p.m. the tornado warning was issued for the period of 3:00 p.m. to 6:00 p.m. A supercell formed just west of the base just before 6:00 p.m., and soon after the tornado crossed the air base. The resulting damages were much less than from the tornado just days earlier.

Bombers damaged during March 25, 1948 storm at Tinker AFB.

The success of that forecast spurred on continued research. There was little known about the weather patterns associated with severe storms and the two Air Force officers became pioneers in severe weather forecasting research. Fawush and Miller published a number of papers on their research, and in 1967 Miller published a technical report for the Air Force titled "Notes on Analysis and Severe-Storm Forecasting Procedures of the Air Force Global Weather Central." It was revised in 1972 and became the bible of severe weather forecasting at that time.

One of the dozens of charts depicting conditions favorable for severe weather in Miller's technical report. This is a composite chart showing a number of features, The stippled area is the extent of sever e weather occurrences. The dashed double lines located the major tracks and occurrences of tornadoes.

In July of 1950 the U.S. Weather Bureau rescinded its ban on using the word "tornado" allowing its use in public forecasts. Unfortunately, the Federal Communications Commission continued to ban its use on radio and television for the same reason as the Weather Bureau's initial ban. This continued until 1952, when meteorologist Harry Volkman broadcast the first televised tornado warning over WKY-TV (now KFOR-TV) in Oklahoma City. The warning was issued at the urging of the station manager, who had obtained the alert from the Air Weather Service and felt it was the station's responsibility to alert its viewers about impending severe weather.

For more information, see the following sources:

Tornado Forecast - 50 Years - The Historic Forecast

Maddox, Robert A.; Crisp, Charlie A. (August 1999). "The Tinker AFB Tornadoes of March 1948" (PDF). Weather and Forecasting (American Meteorological Society) 14 (4): 492–499.

Wednesday, March 19, 2014

Dusty Days in West Texas

While the eastern half of the country deals with lingering winter weather, the dry, warm conditions in the western U.S. are creating problems there.  It was a dry winter throughout the Southern Plains and southwest, especially from the Texas Panhandle west to eastern California and southern Nevada.  In much of this region precipitation over the past 90 days has ranged from less than 10 to about 50 percent of normal.

Credit: NOAA Advanced Hydrological Prediction Service
 As you may expect, drought continues to persist with the lack of rain. Much of the Texas Panhandle is depicted in Extreme to Exceptional Drought on the U.S. Drought Monitor.

U.S Drought Monitor for March 11, 2014. Red areas are in Extreme Drought, dark red in Exceptional drought.

View looking north on 19th St. in Lubbock, TX on March 18.
Photo credit: Alex Pham
Dry, dusty soils and the windy weather of spring often combine to produce a lot of blowing dust inthe Plains.  Western Texas has experienced two dust storms, or haboobs, in the past week.  One occurred last Tuesday, March 11, and another one yesterday. The  one yesterday developed as a strong cold front moved through the Panhandle.  One interesting aspect of this dust storm was that it was clearly visible on radar.  Here is a radar image at 2:56 p.m. CDT on March 18. What looks like a precipitation echo (in green and blue) is actually the dust cloud.

Radar image of Texas dust cloud on March 18, 2014.

Here is a satellite image about two hours later. The lower sun angle provides better contrast for seeing the dust clouds (outlined in yellow).  The southern dust cloud is occurring just behind the cold front boundary and originated in eastern New Mexico. The northern dust cloud developed along the leading edge of the much cooler air and a wind shift to the north. This is the huge dust cloud, or haboob, that swept across the Panhandle.Winds were regularly gusting 35 to 45 mph with some gusts exceeding 60 mph. Visibilities were reduced to 1/4 mile or less with near "brownout" conditions.

The leading edges of two dust clouds are evident in this visible satellite image.
Surface weather observation plot with the approximate position of the cold front (southern blue line) and the wind shift associated with the cold air and the wall of dust (northern blue line)

The National Weather Service in Lubbock, TX has a web page describing this event along with more photos and animations.  They also have more information on the dust storm on March 11, 2014.
The Texas Mesonet also has a page describing these two dust storms..

Monday, March 17, 2014

Ice on the Great Lakes

On March 6th ice coverage on the Great Lakes peaked at 92.2 percent, the second greatest concentration on record (records have been kept since 1973). The greatest amount recorded was 94.7 percent in the winter of 1978-1979.

As of yesterday (March 16) ice coverage was down to a little over 75 percent and should continue to decline as the weather warms.

Ice cover is one indicator of the severity of winter in the region. It takes prolonged periods of cold weather to produce the coverage and thickness of ice seen this winter.  Ice thickness exceeded 30 inches in some areas, although exact thickness is undetermined as the ice augers bottom out at 30 inches.

Although the negative impacts of ice seem readily apparent (limiting navigation and shipping), there are benefits to the ice cover on the lakes.

Once the lakes become ice covered, the potential for lake-effect snow and lake enhancement of snow diminishes. Lake-effect snows result from the development of precipitation as cold air moves over the relatively warm waters of the lakes. Once the source of "heat" and moisture is cut off so is the potential for enhanced snowfall. In the same vein, the ice cover prevents evaporation from the lakes which can help contribute to higher water levels on the lakes, important to navigation and to those communities who rely on the lakes for water supply.  The ice cover can benefit the fishing industry in the lake. Whitefish, for example, spawn in shallow water, and the ice cover protects their eggs from damaging wind and wave action. When there is little or snow cover on the ice, light penetration promotes the growth of algae, an important nutrient in the food chain. Of course, thick, stable ice on the near-shore areas is beneficial to recreational activities such as ice fishing.

How long is ice likely to remain on the lakes?  On the shallower lakes (Erie and Huron, for example) ice cover develops more rapidly and with greater concentration, but also will decline more rapidly than on the deeper lakes. On average the date of last ice is generally sometime in March in the southern Great lakes, but late April in some of the bays in the northern Great Lakes.

However, this is not an average year. In 1979, the year with the greatest ice cover, the date of last ice was mid to late May across the western half of Lake Superior.

There will be some impacts on spring and early summer weather as a result of the extensive ice cover. On a regional basis, air masses that cross the Great Lakes will be modified (cooled) more than normal and that could result in a cooler than normal spring. The delayed warming of the waters due to the ice will mean that near-shore areas subject to lake breezes are likely to find those to be very chilly breezes through early summer.

If you would like to learn more about Great lakes ice, visit the Great Lakes Ice Cover page of NOAA's Great Lakes Environmental Research Laboratory located in Ann Arbor, MI.

Tuesday, March 11, 2014

Just When You Thought It Was Safe to Go Outside...

The last several days have seen a big spring tease across much of the country. Warm air streamed into the Plains and Midwest today with highs reaching the mid 70s from Nebraska though southern Iowa and all of Missouri. St. Louis reached 80°F this afternoon. The 60s could be found as far east as Pennsylvania and the mid-Atlantic states.

Maximum temperatures ending at 7:00 p.m. CDT March 11, 2014

By the time Wednesday morning rolls around things will look and feel much different. A cold front dropped south through the central U.S. this afternoon. and a wave of low pressure is moving along that front. Showers and thunderstorms broke out this evening across Missouri and Illinois, and in the cold air further west snow was falling.

Surface map at 7:00 p.m. CDT March 11, 2014
Overnight the rain will change to snow and a band of 4 to 6 inches of snow or more is expected from north central Illinois east-northeast across southern Michigan and through much of New York into New England.

Probabilities for 4, 8, and 12 inches of snow, and for >+0.25 inch icing
from 7:00 p.m. CDT March 11 to 7:00 p.m. CDT March 12

The good news is that this will be followed by another warming trend by the end of the week in the central U.S. However, that will be short-lived as another cold front plunges south and returns temperatures in the eastern half of the U.S. to as much as 8 to 10 degrees below normal.

Maximum temperature departure from normal forecast for Monday, March 17.

Wednesday, March 5, 2014

Meteorological Winter is Over, but Winter Weather Is Not

The "official" three-month winter season concluded on February 28, but apparently no one bothered to inform Mother Nature. Meteorological winter runs from December 1 to the last day of February, though winter weather does begin and end well after those endpoints. The transition from winter to meteorological spring was marked only on the calendar as conditions were more like that of January in much of the country.

The most recent storm is now out to sea, but as it crossed the U.S. the last three days it left a blanket of snow and ice in its wake. On Sunday snow, sleet, and freezing rain fell across the Midwest and Ohio Valley, with upwards of 7 to 8 inches inthe Missouri Ozarks. On Monday two to six inches of snow covered the ground from southeastern Ohio through northern Virginia and southern New Jersey.  Today snow fell from southern Minnesota and  Iowa across southern Wisoncins and northern Illinois.

Earlier this week subzero low temperatures covered the northern Midwest and Great Lakes.

Minimum temperatures for Monday, March 3, 2014

A little over 51 percent of the lower 48 states had snow on the ground as of this morning.

The final numbers on meteorological winter are still being tallied by the National Climatic Data Center and will be available in a few days. However, we already know the this winter will be in the record books for one reason or another. Detroit, MI is experiencing one of its most severe winters on record and has piled up 83.8 inches of snow this season so far, a little less than 10 inches short of the all time record of 9.6 inches in 1880-1881. Out of the 92 days in meteorological winter, Embarrass, MN recorded 32 days with a minimum temperature of -30°F or lower  (yes, you read that correctly), a new state record for Minnesota, and through today there have been 10 days with -40°F or lower. The average temperature for the winter was -5.5°F.

Daily maximum and minimum temperatures for Embarrass, MN from December 1, 2013 to March 5, 2014

  In the east snowfall in Philadelphia at the end of February at 59.5 inches, 40.5 inches above normal (with another 3.4 inches since then). New York City snowfall totaled 57.3 inches at the end of February, 36 inches above normal.

Here is an neat animation of the cold air outbreaks over the U.S. for January through February.  This was produced by.the Computational & Information Systems Laboratory at the National Center for Atmospheric Research in Boulder, CO. The maps depict surface air temperatures, which are measured at a height of 2 meters (about 6 feet) above ground level.

 While the eastern half of the U.S. has been dealing with brutal winter conditions, the western U.S. and Alaska have been unusually warm.  Anchorage experienced its 15th warmest winter on record.  In contrast to snowfall in the Midwest and east, Anchorage snowfall was at 53.4 inches at the end of February, almost 7 inches below normal.  The Iditarod Sled Race from Anchorage to Nome (about 1,000 miles) has been hampered this year by snowless trail conditions. The lack of snow and rough trails have already knocked 11 mushers out of the race. The race began on March 2nd.