10:30 AM | 2014 Tropical and Mid-Atlantic Summer Outlooks

httpv://youtu.be/-ZYdt0lt3HU

Discussion

Tropical Outlook Summary The overall numbers may be down this year in terms of the number of Atlantic Basin tropical storms, but the sea surface temperature pattern in the western Atlantic and Gulf of Mexico makes the U.S. quite vulnerable to some late season tropical hits. The two major factors involved with this year’s tropical outlook include a developing El Nino in the equatorial Pacific Ocean and the current sea surface temperature pattern across the Atlantic Ocean which features an area of colder-than-normal waters off of the west coast of Africa, but warmer-than-normal temperatures near the U.S. east and Gulf of Mexico coastlines. As a result, there are likely to be fewer-than-normal “African-wave” type tropical systems this season that travel long distances across the tropical Atlantic Ocean and perhaps more in the way of “home-grown” type systems that develop much closer to the U.S. Typically, the “African-wave” type of tropical storm dominates the first half of the season (June/July/early August) and the “home-grown” type of tropical storm plays more of an important role during the second half of the season (late Aug/Sept/Oct).

In a typical Atlantic Basin tropical season, there are about 12 named storms with 6 or 7 reaching hurricane status and only 2 or 3 actually reaching major status (i.e., category 3, 4 or 5). This year there may be more on the order of 8-10 named storms with 3-5 reaching hurricane status, but despite these expected slightly below normal overall numbers, the U.S. could actually see more tropical activity than usual due to the sea surface temperature pattern in the western Atlantic and Gulf of Mexico. One final note, fortunately, the US mainland has not been struck by a "major" hurricane (i.e. category 3 or higher) since Hurricane Wilma in October 2005 and this is one of the longest stretches ever recorded without a "major" hurricane hit. In fact, when the 2014 official hurricane season begins on June 1st, it will have been 3,142 days since the last category 3+ storm made landfall in the US and this shatters the record for longest stretch between intense hurricanes in the US going back to 1900.

El Nino in the tropical Pacific Ocean What goes on in the tropical Pacific Ocean does indeed have an effect on the tropical Atlantic Ocean. El Nino, which refers to warmer-than-normal waters in the central and eastern tropical Pacific Ocean, affects global weather patterns and tends to produce faster-than-usual high-altitude winds over the tropical Atlantic Ocean. This increase in the upper atmospheric winds over the tropical Atlantic Ocean is an inhibiting factor for tropical storm formation in the Atlantic Basin and tends to rip apart growing storms. Currently, there are numerous signs for the development of an El Nino this summer in the tropical Pacific Ocean and this should inhibit storm formation in the tropical Atlantic Ocean.

Atlantic Ocean sea surface temperature pattern The main breeding grounds for Atlantic Ocean tropical systems are in the region between the west coast of Africa to the Caribbean Sea and the Gulf of Mexico. Above normal sea surface temperatures in this region generally help to intensify tropical waves that come off of the west coast of Africa and move westward in the trade winds. This year, however, there is a pocket of colder-than-normal sea surface temperatures off of the west coast of Africa and this should inhibit the formation of tropical storms in that part of the tropical Atlantic Ocean. On the other hand, there are warmer-than-normal waters just off the U.S. east coast and across much of the Gulf of Mexico and this should aid in the development of storms in nearby locations such as the Caribbean Sea, Gulf of Mexico or just off the Southeast U.S. coastline.

Mid-Atlantic Summer Outlook In general, I believe there is little chance for a hot and dry summer in the Mid-Atlantic region, but rather somewhat near normal in terms of precipitation with a slight leaning towards the cool side of normal when it comes to temperatures. The developing El Nino in the tropical Pacific Ocean will play a role in our summertime weather pattern and there are two other factors that should turn out to be meaningful. First, the far higher-than-normal Great Lakes ice cover extent this past winter and spring is generally a useful indicator for normal to cooler-than-normal temperatures in the Mid-Atlantic region (not necessarily because of the ice cover itself, but because of the continuing overall weather pattern which produced the anomalous ice cover in the first place). Second, soil moisture content is rather high around here thanks in part to the very snowy winter and also to the plentiful spring rains that we have experienced. High soil moisture content tends to significantly reduce the chances for summertime drought and excessive heat.

11:50 AM | El Nino likely on the way, but odds are against a "super" one

[computer model forecasts courtesy International Research Institute at Columbia University]

Discussion

Summary El Nino, which refers to warmer-than-normal waters in the central and eastern tropical Pacific Ocean, can have an important effect on global weather patterns; especially, if it develops into what is commonly referred to as a “super” El Nino. In fact, we have had “super” El Nino’s in the tropical Pacific Ocean in the not too distant past (e.g., 1997-1998, 1982-1983) which caused global temperatures to spike to well above normal levels for a sustained period of time. Indeed, there are numerous signs that an El Nino is likely to develop this summer in the tropical Pacific Ocean and continue into the fall season and it is likely to have an impact on the upcoming tropical season in the Atlantic Basin. Many are suggesting that this potential El Nino will evolve into a “super” El Nino; however, I believe the odds are against that and I provide some of the reasoning in this discussion and also in the video (below).

Reasoning against a "super" El Nino Several dynamical computer forecast models tend to develop an El Nino during the summer months in the tropical Pacific Ocean, but then project it to level out or even weaken as we approach the late fall and upcoming winter season. One model in particular that I track from Japan called the JAMSTEC has a pretty good track record with respect to El Nino forecasting and while it does predict an El Nino to develop during the summer months and continues it through the fall season, it then tends to weaken it heading into the upcoming winter season. Also, if one looks at the recent history of the “multivariate El Nino Southern Oscillation (ENSO) index”, it is generally the case that “super” El Nino’s tend to follow relatively warm periods with weak El Nino conditions in the tropical Pacific Ocean whereas weaker El Nino’s tend to follow relatively cold periods (i.e., La Nina conditions). The last few years have in fact been dominated by La Nina (cold) conditions in the tropical Pacific Ocean which is supporting evidence that a “super” El Nino is less likely to form. Finally, another important index that meteorologists track with regard to the state of the tropical Pacific Ocean is called the Southern Oscillation Index (SOI). This index gives an indication of the development and intensity of El Nino or La Nina events in the tropical Pacific Ocean and it is calculated using the pressure differences between Tahiti and Darwin. If there are negative values of the SOI then this can be indicative of upcoming El Nino episodes. A “long-lasting and sharply negative” SOI value can be a useful predictor of a very strong or “super” El Nino. Currently, the SOI values that we are observing are nowhere near the values experienced during or just preceding the “super” El Nino years of 1982-1983 and 1997-1998.

Potential winter implications One final note, the difference between a weak and “super” El Nino can be huge when it comes to impact on winter weather in the Northeast US. An ongoing “super” El Nino next winter would increase the odds of a warm winter in the Northeast US whereas a weaker El Nino - especially one based in the central tropical Pacific Ocean - can still allow for a cold and snowy winter (more on that outlook at a later time).

Video

httpv://youtu.be/_s1LUjWAPBY

2:20 PM | 2014 tornadoes near historic lows across the US thanks in large part to the persistent cold air outbreaks

Discussion

While the middle of this week will likely bring the threat for tornadoes into the central part of the country, there is nothing but good news so far this year on the tornado front and a large part of the thanks can go to the persistent cold air outbreaks that we have experienced during the spring in much of the eastern half of the nation with the primary focus across the Great Lakes and Upper Midwest. In fact, the number of tornadoes reported to NOAA’s Storm Prediction Center (SPC) through April 20th is 109 (above) and this is one of the slowest starts in years to the tornado season - perhaps even as long as a century - which continues a downward trend that began a few years ago. The average number of tornadoes for this time of year is 413 based on the period from 2005-2013. The yearly nationwide tornado totals for the last two years (943 in 2013, 1119 in 2012) were the lowest annual amounts of any of the past ten years according to NOAA’s SPC. One other favorable bit of news on the tornado front is the fact that we have not had an EF-3 or stronger tornado in the last 152 days which is the 4th longest span in the past 60 years without that type of strong tornado (below).

The overriding reason for the low number of tornadoes so far this year - as well as for much of last spring - has to do with the fact that the persistent cold weather pattern in much of the central and eastern U.S. has greatly reduced the chance for severe weather by inhibiting moisture-laden warm air from the Gulf of Mexico to flow northward into the southern U.S. This is an important, and generally necessary, ingredient for severe weather and the generation of tornadoes. Indeed, this same persistent cold weather pattern has contributed to the record high ice cover extent across the Great Lakes – still continuing at this late date – and more cold air masses are in sight for this region of the country through at least next week and the beginning of May.

11:00 AM | Global sea ice areal extent running above normal and experiencing a recent spike

[Global sea ice anomaly versus the 1979-2008 mean; recent spike pushes sea ice areal extent to nearly 1 million square kilometers above the norm)

Discussion

Overall summary The Great Lakes has received a lot of attention lately for its tremendous build-up of ice this winter – and it still stands at historically high levels for ice coverage (below) for this time of year - but the northern hemisphere as a whole remains at below-normal levels for sea ice areal extent by about 566,000 square kilometers (versus 1979-2008 mean). On the other hand, the southern hemisphere sea ice areal extent continues to be at or near record high levels for this time of year at around 1,342,000 square kilometers above the norm and this has boosted global sea ice to above-normal levels on the order of 1 million square kilometers. In fact, there has actually been a spike in recent weeks (above) with respect to global sea ice areal extent to these levels which have been seen only rarely in the past several years.

[Great Lakes ice coverage remains above 50%; well above all years back to the winter season of 1980/1981]

Northern Hemisphere Sea Ice The northern hemisphere sea ice areal extent is still below-normal for this time of year although it has gained significantly in the past several weeks relative-to-normal and remains well above the lowest points of the past few years. The northern hemisphere sea ice areal extent has generally trended lower since the mid 1990’s to mostly below-normal levels since the turn of the century. In the past several years, however, there has been a leveling off of the trend line in terms of sea ice areal extent at those below-normal levels. In the time period before the mid 1990’s, the sea ice extent was generally above-normal dating back to 1979.

This directional change in trend that developed during the mid 1990’s correlates quite well with a northern Atlantic Ocean sea surface temperature cycle that is tracked by meteorologists through an index called the Atlantic Multidecadal Oscillation (AMO). Indeed, the Atlantic Ocean has a significant impact on northern hemisphere sea ice and the AMO index flipped in phase during the mid 1990’s from negative (cold) to positive (warm) and the trend changed at that point in time. Once the northern Atlantic Ocean sea surface temperatures flip back to cooler-than-normal values – perhaps in the next few years - the northern hemisphere sea ice areal extent should return to the normal or above-normal levels seen prior to the mid 1990’s.

Southern Hemisphere Sea Ice The southern hemisphere sea ice areal extent continues its recent impressive run at record or near record high levels for this time of year when compared to all prior years in the satellite record-keeping era which began in 1979. This remarkable period of increasing sea ice areal extent in this part of the world has actually been occurring for the past few years with only a few brief exceptions to that overall upward trend. Back in 2011, the southern hemisphere sea ice areal extent was at below-normal levels, but it is currently running well above-normal at levels seen only a couple of times dating back to the late 1970’s (all data courtesy University of Illinois "cryosphere" web site with data originating from NOAA/NCEP Snow and Ice Data Center).

The video discussion (below) details the current ice coverage situation in the Great Lakes, the northern and southern hemispheres and across the globe.

Video

httpv://youtu.be/Vwtt3SjMOFw

1:30 PM | Tornado threat increases tomorrow in the mid-Mississippi Valley, but so far the numbers this year are way down

Discussion

Tomorrow, the mid-Mississippi Valley will have a threat for severe storms and tornadoes and it may very well be the greatest threat of tornadoes that we have seen all year; however, the overall nationwide numbers so far this year are way down and this continues a downward trend that began a few years ago. In fact, the number of nationwide tornadoes through the end of March as reported by NOAA’s Storm Prediction Center (SPC) was 70 and this is the lowest amount in the “January through March” time period of any of the past ten years. The average number of tornadoes for the first three months of the year are 243 (based on the period from 2005-2013). The yearly nationwide tornado totals for the last two years (943 in 2013, 1119 in 2012) were the lowest annual amounts of any of the past ten years according to NOAA’s SPC.

The overriding reason for the low number of tornadoes so far this year as well as for the beginning three months of last year has to do with the fact that the persistent cold and snowy weather pattern in much of the central and eastern U.S. basically squashed the threat for severe weather. A pronounced southward dip in the polar jet stream frequently pushed cold air masses into the Gulf of Mexico and this prevented deep, moisture-laden warm air from that region to flow northward into the southern U.S. – an important, and generally necessary, ingredient for the generation of tornadoes.

As far as tomorrow is concerned, a strong upper level trough will swing out of the western states into the middle of the country and combine with an influx of warm, moisture-rich air from the Gulf of Mexico to increase the chances for severe weather and tornadoes in the mid-Mississippi Valley region. Specifically, this general threat area on Thursday will likely run from northern Louisiana to Missouri with the greatest threat perhaps centered on the state of Arkansas. The threat area for severe weather will shift eastward on Friday into the Ohio Valley albeit in a slightly weakened state.

11:30 AM | ***Baseball is back and so is the "Home Run Weather" app!

Discussion

It has long been contemplated that weather conditions have an effect on the distance a baseball can travel. More home runs are seemingly hit on hot days or on days with the wind blowing out.

Who can forget the many games at Wrigley Field that have featured numerous home runs as the wind raced out towards Waveland Avenue? Mike Schmidt cranked four home runs on just such a day at Wrigley Field in April of 1976. That game featured nine home runs and 34 total runs and a wind blowing out strongly ahead of a cold front. Not surprisingly, most of the games with four home runs hit by an individual player have occurred with temperatures of at least 80 degrees or with a strong wind blowing out. Conversely, most people would agree that fewer home runs are hit on cold days or with the wind blowing in. The old Candlestick Park in San Francisco frequently offered such weather.

The distance that a baseball travels is indeed impacted by atmospheric conditions. In general, the less dense the air is, the farther a baseball can travel. Humidity plays a crucial role in air density. Air with higher humidity is actually less dense than drier air. This may be contrary to perception and many baseball fans have no doubt heard baseball announcers incorrectly use the phrase “heavy humid air” on a hot summer night. Dry air is mostly comprised of diatomic oxygen and nitrogen (i.e. O2 and N2) whereas water vapor (H2O) is composed of one oxygen atom and two hydrogen atoms and the moist air has a lower overall atomic mass than dry air. Thus, at a constant temperature, the more water vapor that displaces the other gases, the less dense the air will become.

Additionally, hot air is less dense than cold air and higher altitude air is less dense than air at sea level. It is for this reason that so many home runs were hit in Colorado before the humidor was put into place. The elevated humidity in the humidor that stores baseballs for the Rockies home games effectively reduces the distance that a ball will travel in multiple ways: 1) by adding slightly to its weight through absorption of water, 2) by causing the size of the ball to increase slightly which increases air drag and 3) by reducing its “bounciness” factor.

Utilizing sophisticated math and physics, meteorologists and software engineers at The SI Organization, Inc. have investigated this topic which mixes science and baseball. And the results of their efforts are available in a free, real-time baseball weather application called Home Run Weather. Developed for the iPhone and Android devices, the app relates live temperature, atmospheric pressure, humidity, field orientation, wind direction, wind speed and the drag coefficient of a baseball to the user to determine if local weather conditions, for any big league park, are favorable for home runs being hit. Twenty-four hour forecasts are available in addition to live weather.

Two approaches were combined to arrive at a “home run favorability” index, which the app displays on a scale of 0 to 10 (least-to-most favorable). The first approach was to analyze actual weather conditions and home run data over several seasons (Citizens Bank Park was chosen as the venue for this study). The second approach uses a theoretical, physics-based model that determines the distance a ball will travel based on the temperature, relative humidity and atmospheric pressure.

The Citizens Bank Park study yielded some interesting, but perhaps not too surprising, findings. First, temperatures and dew points had a clear trend line relationship with home runs, as generally more home runs were hit in hot and humid air than colder, less-humid air. It was also found that 13-percent more home runs were hit when the wind was blowing out than other wind conditions. Additionally, 6-percent more home runs were hit in the daytime as compared to nighttime games.

A full major league season of testing on the app index produced very encouraging results with respect to the average number of home runs hit per game. The low home run favorability index values (0-3) had an average of 1.38 home runs per game for the full season. The moderate index values (4-7) had an average of 1.95. And the high values (8-10) had an average of 2.47 home runs per game. In addition, the home run favorability index correlated very well with average total runs scored per game. The low home run favorability index values (0-3) had an average of 7.07 total runs per game for the season. The moderate index values (4-7) had an average of 8.08. And the high values (8-10) had an average of 9.45 total runs per game.

Whether you're a fan at the park who's interested in a home run forecast, a spirited fantasy owner or baseball analyst, Home Run Weather should provide some useful information and conversation material. For more details, visit the "Home Run Weather" page on The SI Weather website (just click on the baseball).

3:00 PM | An amazing Atlantic Ocean storm!!

Discussion

One of the worst storms in years continues to pound away at eastern New England and the Canadian Maritime provinces with blizzard conditions and exceedingly high waves in some sections. Winds have been clocked as high as 101 mph earlier this afternoon at a buoy some 20 miles off the Maine coastal town of Jonesport. Earlier in the day, there were wind gusts as high as 82 mph in Nantucket, Massachusetts along with wind-whipped heavy snow of up to 10 inches. These wind gusts may have been the highest recorded in Nantucket since the superstorm of March 1993. Waves as high as 45 feet are beginning to batter Nova Scotia, Canada and its capitol city, Halifax, is all but shut down for the day. This storm intensified at quite astonishing rates from late last night into this morning with an amazing drop in atmospheric pressure of 43 millibars in less than 24 hours. This easily meets the criteria of rapid intensification known to crazy meteorologists as “bombogenesis” which only requires a drop of 24 millibars in 24 hours. The latest pressure reading of the storm is around 964 millibars (and still falling) and this is equivalent to a category 3 hurricane.

2:00 PM | Stratospheric warming and the MJO: two separate signals that are far apart on our planet suggest the colder-than-normal weather will continue in the central and eastern U.S. right into April

Discussion

Overview It looks like our colder-than-normal weather of recent months in the Mid-Atlantic region will continue into the month of April. Two separate signals that are far apart on the planet suggest cold weather will indeed continue in the central and eastern U.S. right into the month of April. The first signal is coming from a tropical disturbance known as the Madden Julian Oscillation (MJO) and the second signal is coming from the highest part of the atmosphere over the North Pole.

Madden Julian Oscillation (MJO)

Background information on the MJO The MJO is a tropical disturbance that propagates eastward around the global tropics with a cycle on the order of 30-60 days. It is a large-scale coupling between atmospheric circulation and tropical deep convection. The MJO has wide ranging impacts on the patterns of tropical and extratropical precipitation, atmospheric circulation, and surface temperature around the global tropics and subtropics. Furthermore, the MJO influences both precipitation and surface temperature patterns across the US. Specifically, one significant impact of the MJO over the U.S. during the northern hemisphere winter is an increase in the frequency and intensity of cold air outbreaks across the central and eastern US.

MJO Phases Research has found that the location of the MJO, or phase, is linked with certain temperature and precipitation patterns around the world. The MJO phase diagram illustrates the progression of the MJO index through different phases, which generally coincide with locations along the equator around the globe. When the index is within the center circle, the MJO is considered weak, meaning it is difficult to discern. Outside of this circle, the index is stronger and will usually move in a counter-clockwise direction as the MJO moves from west to east. The very latest European model MJO index forecast propagates the MJO from its current "phase 1" location in "phases 2 and 3" as we progress through the remainder of the month of March (follow green line in figure above). Phases 2 and 3 for the MJO index typically signal colder-than-normal temperatures this time of year in the central and eastern U.S. (see circled areas below in "phases 2 and 3").

Sudden Stratospheric Warming (SSW)

Overview Another way to monitor the potential for Arctic air outbreaks in the northern U.S. is to follow what is happening in the stratosphere over the polar region of the northern hemisphere. Sudden stratospheric warming (SSW) events in the region of the North Pole have been found to set off a chain of events in the atmosphere that ultimately lead to Arctic air outbreaks from central Canada into the central and eastern U.S. Indeed, there appears to be a significant stratospheric warming event in progress right now over the North Pole that could prolong winter-like conditions across the central and eastern U.S. as we end with March and begin the new month of April (current stratospheric temperature pattern in figure below centered on the North Pole).

SSW Consequences During the winter months in the lower polar stratosphere, temperatures on average are below minus 70 degrees Celsius. The cold temperatures are combined with strong westerly winds that form the southern boundary of the stratospheric polar vortex. The polar vortex plays a major role in determining how much Arctic air spills southward toward the mid-latitudes. This dominant structure is sometimes disrupted in some winters or even reversed. Under these circumstances, the temperatures in the lower stratosphere can rise by more than 50 degrees in just a few days. This sets off a reversal in the west-to-east winds and the collapse of the polar vortex. In recent SSW events, the polar vortex has split into two pieces and that opened the floodgates for Arctic air to move southward. In response to the stratospheric warming at the high latitudes, the troposphere in turn cools down dramatically and this cold air displacement is then transported from the tropospheric high latitudes to the tropospheric middle latitudes. This doesn’t mean that each and every day following an SSW event will be below normal as that will not be the case. However, it does suggest that, based on historical similarities, we could be looking at an overall below-normal temperature pattern in the central and eastern U.S. continuing right into the month of April.

2:00 PM | An upcoming polar stratospheric warming event could prolong winter-like conditions in the central and eastern U.S.

Discussion

One of the ways to monitor the potential for Arctic air outbreaks in the northern U.S. is to follow what is happening in the stratosphere over the polar region of the northern hemisphere. Sudden stratospheric warming (SSW) events in the region of the North Pole have been found to set off a chain of events in the atmosphere that ultimately lead to Arctic air outbreaks from central Canada into the central and eastern U.S. Indeed, there appears to be a significant stratospheric warming event in the offing over the next 10 days or so (above) centered over the North Pole that could prolong winter-like conditions across the central and eastern U.S. as we progress through March and into the month of April.

During the winter months in the lower polar stratosphere, temperatures on average are below minus 70 degrees Celsius. The cold temperatures are combined with strong westerly winds that form the southern boundary of the stratospheric polar vortex. The polar vortex plays a major role in determining how much Arctic air spills southward toward the mid-latitudes. This dominant structure is sometimes disrupted in some winters or even reversed. Under these circumstances, the temperatures in the lower stratosphere can rise by more than 50 degrees in just a few days. This sets off a reversal in the west-to-east winds and the collapse of the polar vortex. In recent SSW events, the polar vortex has split into two pieces and that opened the floodgates for Arctic air to move southward. In response to the stratospheric warming at the high latitudes, the troposphere in turn cools down dramatically and this cold air displacement is then transported from the tropospheric high latitudes to the tropospheric middle latitudes. The entire process from the initial warming of the stratospheric at high latitudes to the cooling in the troposphere at middle latitudes can take several weeks to unfold. This doesn’t mean that each and every day following an SSW event will be below normal as that will not be the case. However, it does suggest that, based on historical similarities, we could be looking at an overall below-normal temperature pattern in the central and eastern U.S. continuing well into the month of April. Indeed, the very latest NCEP Couple Forecast System (CFS) temperature anomaly forecast (below) for the month of April is colder-than-normal for much of the central and the eastern U.S.

1:15 PM | The coldest December/January/February in 35 years for the contiguous U.S. and March is off to an amazingly cold start

[Niagara Falls has frozen over for the second time this winter; courtesy Reuters]

Discussion

December through February The 3-month winter period of December, January and February was the coldest in the last 35 years across the contiguous United States as measured by the U.S. Historical Climatology Network (USHCN). In fact, according to USHCN data, this was the 10th coldest 3-month winter period ever for the contiguous U.S. going back to the late 1800’s (below). The last time nationwide temperatures averaged this low in the December, January and February time frame was during the winter of 1978-1979 which happened to immediately follow two other very cold winters of 1976-1977 and 1977-1978. The cold weather this winter season has been the most dramatic “relative-to-normal” across the Great Lakes and Upper Midwest with some impressive results. For example, Chicago registered its 3rd coldest winter ever in the 3-month time period of December through February with the most days ever having its low temperature at or below zero. Additionally, the ice cover extent on the Great Lakes is at a record high for the month of March and quite close to the all-time record high. Finally, a rarity has occurred at Niagara Falls where the water has frozen over for a second time this winter season (above).

March The month of March has begun in much the same fashion as its three preceding months – namely, much colder-than-normal in much of the U.S. There have been numerous all-time record low temperatures set for the month of March that include the following:

-Atlantic City, New Jersey at 2 degrees (3/4) -Dover, Delaware at 6 degrees (3/4) -Charlottesville, Virginia at 1 degrees (3/4) -Dulles Airport, Virginia at -1 degrees (3/4) -Baltimore, Maryland at 4 degrees (3/4) [this broke the March record that held for the city of Baltimore since 1873] -Kansas City, Missouri at -3 degrees (3/3)

In addition, the following locations have experienced their coldest days ever in the month of March (i.e., the coldest high temperature in March):

-Little Rock, Arkansas at 28 degrees (3/3) -International Falls, Minnesota at -9 degrees (3/1) -Erie, Pennsylvania at 9 degrees (3/3) -Kansas City, Missouri at 5 degrees (3/2)

Finally, the snow cover across the Lower 48 states according to NOAA's National Ice Center is at ~54% which is the highest level in 10 years at this late date in the winter season.

Detailed description of the USHCN data The United States Historical Climatology Network (USHCN) is a high-quality data set of daily and monthly records of basic meteorological variables from 1218 observing stations across the 48 contiguous United States. Daily data include observations of maximum and minimum temperature, precipitation amount, snowfall amount, and snow depth; monthly data consist of monthly-averaged maximum, minimum, and mean temperature and total monthly precipitation. Most of these stations are U.S. Cooperative Observing Network stations located generally in rural locations, while some are National Weather Service First-Order stations that are often located in more urbanized environments. The USHCN has been developed over the years at the National Oceanic and Atmospheric Administration's (NOAA) National Climatic Data Center (NCDC) to assist in the detection of regional climate change. Furthermore, it has been widely used in analyzing U.S. climate. The period of record varies for each station. USHCN stations were chosen using a number of criteria including length of record, percent of missing data, number of station moves and other station changes that may affect data homogeneity, and resulting network spatial coverage.