Chesapeake Bay Climate Impacts Summary and Outlook

Mid-Atlantic Regional Climate Impacts Summary and Outlook: Winter 2021-2022

Highlights

  • A winter storm on January 3 impacted Maryland, Virginia, and Washington, D.C., dropping 12 to 16 inches of snow and causing a traffic backup over a 50-mile stretch of Interstate 95 in northern Virginia that lasted more than 24 hours.
  • Temperatures were generally a few degrees above normal across the region for the winter season. This was largely due to a warmer month of December, with six sites recording their second warmest December on record.
  • The southern and eastern portions of the region experienced below normal precipitation, while areas to the west generally experienced slightly above normal precipitation; the area around Pittsburgh and a part of central Pennsylvania received over 150 percent of their normal precipitation.
  • Despite several winter storms in January and February, the region largely received less than normal amounts of snow.
  • In an analysis of future differences from normal precipitation, we found that future projections of average annual precipitation show greater departures from “normal” across the Mid-Atlantic when using the 1981–2010 normal as a baseline than when comparing to the 1991–2020 normal.

View all climate summaries

Figure 1. Mid-Atlantic Regional Map

A map of the Mid-Atlantic regional highlighting the Chesapeake Bay watershed.

Map showing the Mid-Atlantic region shaded in blue.

This summary focuses on winter weather and climate events in the Chesapeake Bay watershed and provides highlights from the greater Mid-Atlantic region. The winter season is defined as the months of December, January, and February. The MARISA region covers Maryland, Delaware, Virginia, and Pennsylvania and the portions of New York and West Virginia that fall within the boundaries of the Chesapeake Bay watershed, as shown in Figure 1 above. We refer to this region as the Mid-Atlantic region in the rest of the climate summary.

Part 1: Significant Weather Events and Impacts

Winter Weather

After a quiet December, multiple winter storms affected the Chesapeake Bay watershed during January.

On January 3, a storm spread snow cover over much of Virginia, Maryland, and Washington, D.C., with the greatest snowfall totals of 12 to 16 inches falling in northern Virginia and southern Maryland.1 It was the D.C. metro area’s biggest snowstorm in three years; the 6.7 inches of snow registered at Reagan National Airport was the most since January 2019.2 Wind gusts frequently reached 50 miles per hour and occasionally were as high as 70 miles per hour during the storm.3 Travel was significantly disrupted, with thousands of crashes and disabled vehicles.4 For example, by 9:30am, disabled tractor-trailers were reported to be blocking lanes on Interstate 95 in Virginia, and snowfall rates and amounts were high enough that plows became stuck and could not clear the highway of snow.5,6 Hundreds of drivers were stranded in the resulting traffic jam, some for more than 24 hours, along a 50-mile stretch of Interstate 95 in Virginia.7

There were numerous flight delays and cancellations across the Baltimore-Washington metropolitan area, where a few airports issued ground stops due to snow accumulating on runways.8 The heavy, wet snow and gusty winds downed trees and wires, causing around 450,000 customers in Virginia and nearly 100,000 customers in Maryland to lose power.9,10 In some cases, as many as 90 percent of the residents in some counties lost power.11 The storm was among “the five worst winter storms in Dominion Power Virginia’s history”.12 Additionally, the storms’ strong winds combined with higher-than-normal tides led to moderate to major coastal flooding, particularly in the Lower Chesapeake Bay, inundating roads.13,14

Figure 2. Snow in Hurlock, Maryland, from January 3 Snowstorm

Snowfall in Hurlock, Maryland, after a January 3 snowstorm. Photo by Reece Todd / National Weather Service

SOURCE: Reece Todd / National Weather Service

A few days later, from January 6 to 7, another storm dropped snow on portions of the watershed. The greatest snowfall totals of 6 to 8 inches were measured in western and central Maryland and south-central Pennsylvania.15 Winter storm conditions led to difficult travel and school closures.16

On January 16 and 17 another winter storm brought snow, ice, and rain to the watershed. The greatest storm snowfall totals of 12 to 14 inches fell in western Maryland and central New York, where totals also included lake effect snowfall.17,18 Some locations in Maryland and Virginia saw as much as 0.3 inches of ice accumulation.19,20 The storm also produced wind gusts of 30 to 60 miles per hour.21 The storm’s main impact was in creating transportation problems.22 Slick road conditions were reported and Virginia experienced 482 crashes and 486 disabled vehicles on January 16 alone. Travel was therefore discouraged overnight and into the morning of January 17.23

From January 21 to 22, a storm dropped up to 8.5 inches of snow on southeastern Virginia, with the greatest totals falling in Virginia Beach, making it the area’s most significant snowfall since January 2018.24

A storm tracked across the Mid-Atlantic then rapidly strengthened off the East Coast on January 28 and 29, bringing snow and strong winds to portions of Virginia, Maryland, and Delaware.25 Storm snowfall totals were generally 6 inches or less, except on the Delmarva Peninsula where snow totals were up to 14 inches.26,27 Winds gusted as high as 55 miles per hour, resulting in blizzard conditions for coastal areas along the Delmarva Peninsula.28,29 The National Weather Service office in Wakefield, Virginia noted that “these were the first Blizzard Warnings issues for anywhere in the Wakefield County Warning Area since early January of 2018”.30

From February 3 to 4, a storm system brought a range of weather conditions to the watershed. Extreme northern parts of the region in central New York saw all snow, accumulating 6 to 12 inches.31 The rest of central New York and northern Pennsylvania saw a mix of precipitation types including snow, sleet, freezing rain, and rain.32 For example, Williamsport, Pennsylvania saw 0.4 inches of snow, 0.2 inches of freezing rain, and rain.33,34 Meanwhile, much of southern Pennsylvania, Maryland, and Virginia saw rain and little, if any, snow or ice.35 Parts of Pennsylvania saw minor flooding due to heavy rain, snowmelt, and ice jams.36,37

On February 18, a strong cold front moved across the watershed, causing temperatures to drop rapidly.38 Wind gusts of up to 65 miles per hour accompanied the front, downing trees and wires and leading to scattered power outages.39,40

On February 19, a line of snow squalls associated with an Arctic cold front produced a brief period of heavy snow and gusty winds, creating whiteout conditions and a dangerous travel situation in central New York and central Pennsylvania.41 Wind gusts of up to 60 miles per hour along and behind the front downed trees and wires across the region.42,43

From February 24 to 25, the watershed saw another mixed precipitation storm event. The greatest snowfall totals of 4 to 6 inches were measured in the far northern parts of the watershed in central New York.44 The rest of the region saw limited snowfall, rain, and as much as 0.3 inches of ice accumulation, particularly in south-central Pennsylvania and western and central Maryland.45,46 The ice coasted untreated surfaces and led to some downed trees and wires.47,48

Drought

The U.S. Drought Monitor from December 7 showed areas of severe and moderate drought in parts of southern and eastern Virginia and abnormally dry conditions in much of the rest of the state.49 Abnormal dryness was also present in parts of eastern West Virginia and southern and eastern Maryland.50 Dry conditions led several Virginia counties to issue burn bans in early December.51 Below-normal December precipitation caused the dry conditions to intensify, with moderate drought and abnormal dryness expanding in southern parts of the watershed over the course of the month.52

Frequent storms in January eased much of the drought conditions in Virginia, with only small areas of abnormal dryness and moderate drought lingering in western and southern portions of the state.53 Abnormal dryness was also alleviated in several other parts of the watershed, with dryness persisting only in the western half of Virginia, a sliver of southeastern Virginia, northern portions of the Delmarva Peninsula, and south-central Pennsylvania.54

Wet conditions during the first half of February erased moderate drought in Virginia and abnormal dryness in south-central Pennsylvania.55 Areas of abnormal dryness lingered in Virginia, particularly central Virginia, through February.56

Part 2: Seasonal Temperature and Precipitation

Temperature

Figure 3 shows the December 2021 through February 2022 average temperature compared with the climate normal (normal)—i.e., the average temperature from 1991 to 2020.57 The figure shows that the majority of areas experienced temperatures a few degrees above their normal temperatures. Large portions of Virginia, and a few other areas across the region experienced temperatures that were 2–4 degrees Fahrenheit (F) above normal, and small portion of Maryland and Virginia on the Chesapeake Bay experienced temperatures that were 4–6 degrees F above normal. These departures from normal temperatures are similar to what was observed in both the fall and summer 2021 seasons where temperatures were generally 0–2 degrees F above normal.

Figure 3. December 1, 2021 – February 28, 2022, Departure from Normal Temperature (degrees Fahrenheit)

Heat map showing departure from normal temperature (degrees Fahrenheit) in the Mid-Atlantic region.

SOURCE: Northeast Regional Climate Center, 2021 (https://www.nrcc.cornell.edu). Used with permission.

NOTE: Normal temperature is based on the winter season’s average temperature data from 1991–2020. Yellow, orange, and red indicate above-normal temperatures. Blue indicates below-normal temperatures. The boundaries of the Chesapeake Bay watershed are outlined in bold black. Average departure from normal temperature is based on a station’s normal temperature for winter compared with the same station’s winter 2021–2022 average temperature. Station-level departures from normal are spatially interpolated across the region. Both are produced by the Northeast Regional Climate Center. These can be found at https://www.rcc-acis.org/docs_gridded.html.

Eight sites in the Mid-Atlantic experienced average seasonal winter temperatures that ranked among their top 20 warmest on record. The locations and ranks are reported in Table 1. Charlottesville, Virginia experienced its 4th warmest winter on record, Washington, D.C. its 12th warmest, and Salisbury, Maryland its 20th warmest winter on record.

Table 1. Winter Season (December–February) Temperature Rankings

Station Name Avg. Temp
(degrees F)		 Normal Temp
(degrees F)		Rank
(warmest)
Charlottesville, VA 42.0 40.4 4
Dulles Airport, VA 38.7 36.0 7
Richmond, VA 43.3 40.4 10
Lynchburg, VA 41.6 37.9 12
Washington National, DC 41.6 39.7 12
Baltimore, MD 39.3 36.5 19
Harrisburg, PA 35.3 33.3 20
Salisbury, MD 40.4 38.7 20

SOURCE: Northeast Regional Climate Center, 2022 (http://www.nrcc.cornell.edu). Used with permission.

Monthly Temperature Rankings

In December, 13 sites in the Mid-Atlantic experienced temperatures that ranked among their top 20 warmest on record, with six experiencing their second warmest Decembers on record. The locations and ranks are provided in Table 2. In contrast, only one site, Binghamton, New York, experienced a January temperature that ranked within its top 20 coldest on record. Six sites experienced February temperatures ranked within the top 20 warmest on record, including Dulles Airport, Virginia (9th warmest), Washington, D.C. (18th warmest), and Salisbury, Maryland (20th warmest on record).

Table 2. Monthly Temperature Rankings

December Temperature Records (warmest)
Station Name Avg. Temp
(degrees F)		 Normal Temp
(degrees F)		 Rank
(warmest)
Charlottesville, VA 48.2 41.5 2
Dulles Airport, VA 45.0 37.7 2
Richmond, VA 48.9 41.8 2
Harrisburg, PA 41.9 35.8 2
Scranton, PA 39.7 33.3 2
Washington National, DC 47.6 41.7 2
Lynchburg, VA 47.6 38.9 3
Williamsport, PA 38.4 32.8 3
Baltimore, MD 45.5 38.6 4
Salisbury, MD 46.3 40.6 4
Martinsburg, WV 42.5 36.0 4
Binghamton, NY 34.2 28.1 5
Norfolk, VA 49.7 46.1 11
January Temperature Rankings (coldest)
Station Name Avg. Temp
(degrees F)		 Normal Temp
(degrees F)		 Rank
(coldest)
Binghamton, NY 17.6 22.5 15
February Temperature Rankings (warmest)
Station Name Avg. Temp
(degrees F)		 Normal Temp
(degrees F)		 Rank
(warmest)
Dulles Airport, VA 39.7 36.4 9
Charlottesville, VA 43.6 41.4 14
Richmond, VA 44.5 41.0 14
Lynchburg, VA 42.7 38.8 18
Washington National, DC 42.6 40.0 18
Salisbury, MD 41.3 38.7 20

Source: Northeast Regional Climate Center, 2022 (http://www.nrcc.cornell.edu). Used with permission.

Precipitation

Figure 4 shows how the total precipitation for December 1, 2021 through February 28, 2022 differed from normal, with normal being defined as the average winter precipitation from 1991–2020. Winter precipitation amounts includes both rainfall and the liquid equivalent of frozen precipitation. The south and eastern portions of the region experienced below-normal precipitation, with some areas experiencing as little as 50 to 75 percent of their normal precipitation amounts. Areas to the west generally experienced at least their normal amount of precipitation, with portions of central and western Pennsylvania, south-western Virginia, and West Virginia experiencing precipitation that was more than 125 percent of normal. A similar pattern of precipitation was observed during the fall 2021 season where portions of Pennsylvania and New York received above average precipitation while much of the rest of the region was drier than normal.

Figure 4. December 1, 2021 – February 28, 2022, Percentage of Normal Precipitation

A heat map showing departure from normal precipitation for the Mid-Atlantic region for Winter 2021-2022. Source: Northeast Regional Climate Center, 2021

SOURCE: Northeast Regional Climate Center, 2021 (https://www.nrcc.cornell.edu). Used with permission.

NOTE: Normal seasonal precipitation is based on precipitation data from 1991–2020. Brown shades indicate below normal seasonal precipitation. Green shades indicate above normal seasonal precipitation. The boundaries of the Chesapeake Bay watershed are outlined in bold black. Average departures from normal precipitation are based on a station’s normal precipitation for winter compared with the same station’s winter 2021–2022 average amount of precipitation. Station-level departures from normal are spatially interpolated across the region. Both are produced by the Northeast Regional Climate Center. These can be found at https://www.rcc-acis.org/docs_gridded.html.

Four sites in the Mid-Atlantic region saw winter precipitation amounts that ranked in their top 20 driest on record. The locations and ranks are provided in Table 3. Charlottesville, VA, which had its 4th warmest winter on record (shown in Table 1), also experienced its 10th driest winter on record. Dulles Airport, VA and Salisbury, MD similarly ranked within their top 20th warmest and driest winters on record.

Table 3. Winter Season (December–February) Precipitation Rankings

Station Name Precipitation
(inches)		 Normal Precip
(inches)		 Rank
(driest)
Charlottesville, VA 5.53 8.35 10
Dulles Airport, VA 6.66 8.85 14
Salisbury, MD 7.44 10.35 17
Martinsburg, WV 5.60 7.74 20

SOURCE: Northeast Regional Climate Center, 2022 (http://www.nrcc.cornell.edu). Used with permission.

Monthly Precipitation Rankings

In December and January, sites in the Mid-Atlantic saw monthly precipitation totals that ranked among their top 20 on record. Charlottesville and Dulles Airport, Virginia, both experienced their second driest Decembers on record. Eleven sites experienced a December that ranked in their top 20 driest Decembers. In contrast, Dulles Airport, Virginia, saw its 13th wettest January on record, and Norfolk, Virginia, its 17th wettest January on record. Two sites, Salisbury, Maryland and Norfolk, Virginia, experienced a February that ranked in their top 20 driest on record. Three sites experienced a February that ranked in their top 20 wettest on record, including Williamsport and Scranton, Pennsylvania. The locations, ranks and amounts of precipitation are presented in Table 4.

Table 4. Monthly Precipitation Rankings

December Temperature Rankings (driest)
Station Name Precipitation
(inches)		 Normal Precip
(inches)		 Rank
(driest)
Charlottesville, VA 0.26 3.04 2
Dulles Airport, VA 0.46 3.30 2
Baltimore, MD 0.82 3.71 6
Washington National, DC 0.63 3.41 6
Lynchburg, VA 0.94 3.50 7
Harrisburg, PA 0.84 3.43 7
Salisbury, MD 1.24 3.59 8
Martinsburg, WV 0.79 3.00 9
Richmond, VA 1.07 3.51 12
Williamsport, PA 1.37 3.27 15
Binghamton, NY 2.85 3.08 20
January Precipitation Rankings (wettest)
Station Name Precipitation
(inches)		 Normal Precip
(inches)		 Rank
(wettest)
Dulles Airport, VA 3.90 2.94 13
Norfolk, VA 5.47 3.41 17
February Precipitation Rankings (driest)
Station Name Precipitation
(inches)		 Normal Precip
(inches)		 Rank
(driest)
Norfolk, VA 1.62 2.90 18
Salisbury, MD 1.74 3.25 19
February Precipitation Rankings (wettest)
Station Name Precipitation
(inches)		 Normal Precip
(inches)		 Rank
(driest)
Williamsport, PA 4.58 2.31 11
Scranton, PA 3.84 2.07 14
Binghamton, NY 3.33 2.41 20

Source: Northeast Regional Climate Center, 2022 (http://www.nrcc.cornell.edu). Used with permission.

From December 1, 2021, through February 28, 2022, winter snowfall was largely below normal, as shown in Figure 5. This was particularly true for the northern portion of the Mid-Atlantic, with part of central Pennsylvania and southern New York experiencing less than 50 percent of their normal snowfall. In contrast, the Delmarva Peninsula and a small area in south-central Virginia experienced more than 150 percent of their normal winter snowfall amounts. These areas, as seen in Figure 4, generally experienced less precipitation than normal this winter, which indicates that they received more of their total precipitation in the form of snow than they do in an average winter season, driven by the snowy January.

Figure 5. December 1, 2021 – February 28, 2022, Percentage of Normal Snowfall

A heat map showing departure from normal snowfall for the Mid-Atlantic region for Winter 2021-2022. Source: Northeast Regional Climate Center, 2021

SOURCE: Northeast Regional Climate Center, 2021 (https://www.nrcc.cornell.edu). Used with permission.

NOTE: Normal seasonal snowfall is based on snowfall data from 1991–2020. Brown shades indicate below normal seasonal snowfall. Green shades indicate above normal seasonal snowfall. The boundaries of the Chesapeake Bay watershed are outlined in bold black. Average departures from normal precipitation are based on a station’s normal snowfall for winter compared with the same station’s winter 2021–2022 average amount of snowfall. Station-level departures from normal are spatially interpolated across the region. Both are produced by the Northeast Regional Climate Center. These can be found at https://www.rcc-acis.org/docs_gridded.html.

Two sites, Scranton, Pennsylvania and Binghamton, New York experienced one of their top 20 least snowy winter seasons on record, as shown in Table 5. Scranton, Pennsylvania, with a normal snowfall of 30.3 inches, received only 13.0 inches of snow across the months of December, January, and February. In contrast, one site, Salisbury, Maryland, experienced its top 15th snowiest winter season on record and received 14.0 inches of snow, more than double its normal snowfall of 6.8 inches.

Table 5. Winter Season (December-February) Snowfall Rankings

Station Name Snowfall
(inches)		 Normal Snowfall
(inches)		 Rank
(least snowy)
Scranton, PA 13.0 30.3 11
Binghamton, NY 39.3 58.4 12
Station Name Snowfall
(inches)		 Normal Snowfall
(inches)		 Rank
(snowiest)
Salisbury, MD 14.0 6.8 15

Source: Northeast Regional Climate Center, 2022 (http://www.nrcc.cornell.edu). Used with permission.

Both Scranton, Pennsylvania, and Binghamton, New York, experienced one of their 20 least snowy Decembers on record. In contrast, six sites, including Washington National, D.C., and Baltimore, Maryland, experienced January snowfalls that ranked in their 20 snowiest months of January. Five sites experienced February snowfalls that ranked in their top 20 least snowy on record. These included Scranton and Williamsport, Pennsylvania, and Dulles Airport, Virginia. Overall, the region mostly received less than normal amounts of snowfall (Figure 5), with the low amounts of snow in December and February more than compensating for the January snowstorms in Maryland and Virginia detailed in Part 1. The full set of monthly rankings, locations, and amounts of snowfall are shown in Table 6.

Table 6. Monthly Snowfall Rankings

December Snowfall Rankings (least snowy)
Station Name Precipitation
(inches)		 Normal Precip
(inches)		 Rank
(least snowy)
Scranton, PA 1.0 7.7 8
Binghamton, NY 8.5 18.1 13
January Snowfall Rankings (snowiest)
Station Name Precipitation
(inches)		 Normal Precip
(inches)		 Rank
(wettest)
Salisbury, MD 14.4 2.5 7
Norfolk, VA 11.2 3.2 8
Dulles Airport, VA 11.4 6.9 11
Lynchburg, VA 9.5 3.5 18
Baltimore, MD 13.3 6.4 19
Washington National, DC 12.3 4.9 19
February Snowfall Rankings (least snowy)
Station Name Precipitation
(inches)		 Normal Precip
(inches)		 Rank
(least snowy)
Scranton, PA 2.6 10.9 9
Williamsport, PA 2.4 9.3 10
Binghamton, NY 10.5 19.7 12
Dulles Airport, VA 0.9 7.0 19
Harrisburg, PA 2.0 9.4 20

Source: Northeast Regional Climate Center, 2021 (http://www.nrcc.cornell.edu). Used with permission.

Part 3: Spring 2022 Outlook

Temperature and Precipitation

As of February 17, 2022 the NOAA Climate Prediction Center forecasts a 40 to 50-percent chance of above normal temperatures for all of the Mid-Atlantic region for March, April and May 2022.58 This indicates that the forecast has a chance of leaning towards having a warmer than normal spring season.59 The precipitation forecast shows an equal chance of wetter than, drier than, or near-normal conditions for most the Mid-Atlantic region for the same period.60 Western Pennsylvania and New York are the only portions of the region that are forecasted to experience above average precipitation, though the probability is only a 33 to 40 percent chance.61

Drought Incidence

The U.S. Seasonal Drought Outlook describes how drought might change across the United States and categorizes areas by whether drought could develop or become more or less intense. As of February 17, 2022, the Outlook indicates that drought is expected to develop in small portions of south-central, south-eastern, and western Virginia as well as in much of eastern Pennsylvania. 62

Climate Circulation Patterns

NOAA’s Climate Prediction Center, which monitors the likelihood of the occurrence of El Niño and La Niña climate phenomena, has a La Niña advisory active as of February 10, 2022, with a 77-percent chance that La Niña conditions will continue through May 2022.63 Pacific Ocean temperatures are then expected to transition to neutral conditions, with a 56-percent chance of this happening in the May – July 2022 timeframe, indicating that La Niña advisory may end by the end of the spring season. 64 La Niña conditions, may impact temperature and precipitation across the United States over the next few months.65 La Niña conditions are one of the factors taken into account in NOAA’s long term forecasts and seasonal outlooks such as the one included in this climate summary.66 However, other regional climate dynamics and natural climate variability also influence winter weather in the Mid-Atlantic. Additional information on La Niña is available from the Pacific Marine Environmental Laboratory.

Part 4: Future Differences from “Normal” Precipitation

The Fall 2021 edition of the Mid-Atlantic Climate Impacts Summary and Outlook discussed projected future differences from “normal” temperature. One key finding from the Fall 2021 Summary was that the “use of the 1981–2010 ‘old’ normal shows over a half-degree greater increase in future average annual temperature compared to the newly-released 1991–2020 normal.”67 This edition continues this discussion by looking at how use of climate normals impacts understanding of future changes in “normal” precipitation.

“Climate normals are a standardized measure of typical climate conditions, such as average annual temperature and precipitation. The National Oceanic and Atmospheric Administration’s (NOAA) National Centers for Environmental Information (NCEI) calculates these “normals” for the continental United States based on observed conditions from weather stations over a 30-year period.68 Climate normals were first calculated for the 1901–1930 time period and are updated each decade.69 The latest climate normals were calculated over the period of 1991–2020 and were released to the public in May 2021.

By standardizing the time period and datasets used to produce climate normals, climate normals provide a consistent and comparable frame of reference to evaluate how different current weather conditions or future weather and climate forecasts may be from the past.70 However, because these normals are updated every ten years, as climate conditions change, the definition of what it means to be “normal” is also changing in time.”71

Figure 6 shows how the climate normals from 1901 to today compare with the average precipitation from the 20th century (1901–2000). While temperatures have steadily increased compared to the 20th century average over time, we do not see a similar trend with precipitation nationwide. However, since about 1961, much of the United States, including the Mid-Atlantic region, has been getting wetter and wetter.72,73 Therefore, as our definitions of “normal” change to wetter or drier conditions, the projected changes in precipitation due to climate change may seem more “normal” while in actuality being quite different from the amount of precipitation experienced even in the relatively recent past (e.g. in the last few decades).

Figure 6. United States Annual Precipitation Compared to 20th-Century Average Precipitation

Annual U.S. precipitation compared to the 20th-century average for each U.S. Climate Normals period from 1901–1930 (upper left) to 1991–2020 (lower right).

Annual U.S. precipitation compared to the 20th-century average for each U.S. Climate Normals period from 1901–1930 (upper left) to 1991–2020 (lower right).

Source: NOAA NCEI; https://www.noaa.gov/news/new-us-climate-normals-are-here-what-do-they-tell-us-about-climate-change)

The interactive data tool shown in Figure 7 explores how the regular updates of climate normals affect our interpretation of projected future climate changes. Figure 7 shows how future projected total annual precipitation from multi-decadal periods compare to “normal”. This figure compares future projections to the last two climate normals (1981–2010 and 1991–2020) and visualizes the percent change from the “normal” time period to the selected future time period. The absolute difference in precipitation amounts is available for individual locations in the tooltip graphics.

Key Findings

  • Future projections of average annual precipitation show greater departures from “normal” across the Mid-Atlantic when using the 1981–2010 normal as a baseline than when comparing to the 1991–2020 normal.
  • Under the 1981–2010 normal, the Mid-Atlantic on average is expected to experience an increase of nearly 3 inches of precipitation under a low emissions future scenario and nearly 5 inches of precipitation under a high emissions scenario by 2100.
  • By comparison, using the 1991–2020 normal, the Mid-Atlantic would expect to experience an increase of just over 2 inches of precipitation under a low emissions future scenario and almost 4.5 inches of precipitation under a high emissions scenario by 2100.
  • By 2100, use of the 1981–2010 normal shows over a half-inch increase in future total annual precipitation than with the 1991–2020 normal under both future emissions scenarios.

Figure 7. Percent Difference from “Normal” Total Annual Precipitation

How to Use the Tool

Selecting Time Periods and Future-Emissions Scenarios
Use the slider to the right of the maps to adjust the 30-year period used to calculate changes in future precipitation relative to each climate normal. Users can also select the future emissions scenario (Low or High Emissions).

Viewing Variability Within a Location
Hover or tap over a point of interest. A window will pop up that displays changes in precipitation by time period and climate normal. You can also use the State and Country filters to the right of the map to zoom into a location of interest.

Technical Notes

Localized Constructed Analogs (LOCA) is a downscaled climate data product available at 1/16-degree (6-km) resolution over the continental United States. LOCA data sets74 include the 32 climate models available in the Coupled Model Intercomparison Project 5 (CMIP5) archive, for two future greenhouse gas concentration trajectories: a low-emissions future, Representative Concentration Pathway (RCP) 4.5;75 and a high-emissions future, RCP 8.5.76 For this study, we used LOCA data over the Chesapeake Bay watershed from 1981–2100 (or 2099 for some models). Access LOCA datasets and learn more about the methodology.

Data were processed by the Northeast Regional Climate Center to calculate the average annual precipitation.

Back to top

The Mid-Atlantic Regional Integrated Sciences and Assessments (MARISA) Seasonal Climate Impacts Summary and Outlook is a quarterly series produced by the MARISA program, a collaboration funded by NOAA through the RAND Corporation and researchers at Pennsylvania State University, Johns Hopkins University, Cornell University, and the Virginia Institute of Marine Science, Morgan State University, and Carnegie Mellon University. This series draws information from regional climate centers, news and weather information, and regional-specific climate data sets for the benefit of policymakers, practitioners, residents, and community leaders in the Mid-Atlantic region. Projections of weather and climate variability and change in the Mid-Atlantic region come from the best available scientific information. For any questions or comments, please contact Krista Romita Grocholski at Krista_Romita_Grocholski@rand.org.

This edition of the MARISA Seasonal Climate Impacts Summary and Outlook was authored by Krista Romita Grocholski (RAND Corporation), Michelle E. Miro (RAND Corporation), Lena Easton-Calabria (RAND Corporation), Jessica Spaccio (Cornell University), Samantha Borisoff (Cornell University), and Arthur T. DeGaetano (Cornell University).

Citation: Romita Grocholski, Krista, Michelle E. Miro, Lena Easton-Calabria, Jessica Spaccio, Samantha Borisoff, and Arthur T. DeGaetano, Mid-Atlantic Regional Climate Impacts Summary and Outlook: Winter 2021–2022. Santa Monica, CA: RAND Corporation, 2022.

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Footnotes

  1. https://www.weather.gov/lwx/pnsmap?type=snow&date=20220103&option=snow Return to text ⤴

  2. https://www.washingtonpost.com/weather/2022/01/03/dc-snow-winter-storm-warning/ Return to text ⤴

  3. https://www.weather.gov/akq/Jan3-2022SnowStorm Return to text ⤴

  4. https://twitter.com/VSPPIO/status/1479129782944210945 Return to text ⤴

  5. https://www.washingtonpost.com/transportation/2022/01/27/i95-traffic-backup-winter-storm/ Return to text ⤴

  6. https://www.washingtonpost.com/transportation/2022/01/27/i95-traffic-backup-winter-storm/ Return to text ⤴

  7. https://www.npr.org/2022/01/04/1070203698/interstate-95-traffic-jam-virginia Return to text ⤴

  8. https://www.wusa9.com/article/weather/live-blog-updates-snowy-weather-dc-area-overnight/65-2e482884-baef-4850-9539-a14bf24f7b0e Return to text ⤴

  9. https://www.weather.gov/akq/Jan3-2022SnowStorm Return to text ⤴

  10. https://www.delmarvanow.com/story/news/2022/01/03/power-outages-impact-maryland-delaware-virginia-snowstorm/9079539002/ Return to text ⤴

  11. https://www.weather.gov/akq/Jan3-2022SnowStorm Return to text ⤴

  12. https://news.dominionenergy.com/2022-01-04-Dominion-Energy-Restoring-Power-Following-Top-Five-Most-Damaging-Winter-Storm Return to text ⤴

  13. https://www.weather.gov/akq/Jan3-2022SnowStorm Return to text ⤴

  14. https://www.pilotonline.com/weather/vp-nw-snow-weather-impacts-20220103-55ztstzqsjcldkjr624epzpnaq-story.html Return to text ⤴

  15. https://twitter.com/NWSEastern/status/1479571392051961862/photo/1 Return to text ⤴

  16. https://www.wbaltv.com/article/snow-expected-thursday-friday-january-6-2022/38676633 Return to text ⤴

  17. http://mesonet.agron.iastate.edu/wx/afos/p.php?pil=PNSBGM&e=202201180157 Return to text ⤴

  18. http://mesonet.agron.iastate.edu/wx/afos/p.php?pil=PNSLWX&e=202201171728 Return to text ⤴

  19. http://mesonet.agron.iastate.edu/wx/afos/p.php?pil=PNSLWX&e=202201171728 Return to text ⤴

  20. https://www.weather.gov/akq/Snowjan16-2022 Return to text ⤴

  21. http://mesonet.agron.iastate.edu/wx/afos/p.php?pil=PNSLWX&e=202201172340 Return to text ⤴

  22. https://www.wfxrtv.com/weather/safetyinthestorm/travel-continues-to-be-hazardous-in-central-swva-due-to-winter-storm-active-crash-shuts-down-i-81-north-in-roanoke-county/ Return to text ⤴

  23. https://www.wfxrtv.com/weather/safetyinthestorm/travel-continues-to-be-hazardous-in-central-swva-due-to-winter-storm-active-crash-shuts-down-i-81-north-in-roanoke-county/ Return to text ⤴

  24. https://www.weather.gov/akq/Jan22-2022Snow Return to text ⤴

  25. https://www.weather.gov/akq/Jan29-2022SnowStorm Return to text ⤴

  26. https://www.weather.gov/akq/Jan29-2022SnowStorm Return to text ⤴

  27. http://mesonet.agron.iastate.edu/wx/afos/p.php?pil=PNSPHI&e=202201301650 Return to text ⤴

  28. https://www.weather.gov/akq/Jan29-2022SnowStorm Return to text ⤴

  29. https://twitter.com/NWSEastern/status/1487500885534126094 Return to text ⤴

  30. https://www.weather.gov/akq/Jan29-2022SnowStorm Return to text ⤴

  31. https://twitter.com/NWSEastern/status/1490068269511938059/photo/1 Return to text ⤴

  32. https://www.weather.gov/bgm/pastWinterFebruary042022 Return to text ⤴

  33. https://mesonet.agron.iastate.edu/wx/afos/p.php?pil=PNSCTP&e=202202050133 Return to text ⤴

  34. http://climod2.nrcc.cornell.edu/ Return to text ⤴

  35. http://climod2.nrcc.cornell.edu/ Return to text ⤴

  36. https://twitter.com/NWSStateCollege/status/1489427074024501250 Return to text ⤴

  37. https://twitter.com/NWSStateCollege/status/1489611478793535491 Return to text ⤴

  38. https://twitter.com/capitalweather/status/1494671615086444549 Return to text ⤴

  39. https://www.weather.gov/lwx/pnsmap?type=wind&date=20220218&option=wind Return to text ⤴

  40. https://twitter.com/capitalweather/status/1494677144001261568 Return to text ⤴

  41. ttps://twitter.com/NWSStateCollege/status/1495039204732317698 Return to text ⤴

  42. http://mesonet.agron.iastate.edu/wx/afos/p.php?pil=PNSLWX&e=202202200633 Return to text ⤴

  43. http://mesonet.agron.iastate.edu/wx/afos/p.php?pil=LSRLWX&e=202202200634 Return to text ⤴

  44. https://twitter.com/NWSEastern/status/1497621658525331456/photo/1 Return to text ⤴

  45. http://mesonet.agron.iastate.edu/wx/afos/p.php?pil=PNSCTP&e=202202251950 Return to text ⤴

  46. http://mesonet.agron.iastate.edu/wx/afos/p.php?pil=PNSLWX&e=202202252006 Return to text ⤴

  47. https://twitter.com/SGuzewich/status/1497180707134840859 Return to text ⤴

  48. http://mesonet.agron.iastate.edu/wx/afos/p.php?pil=LSRLWX&e=202202251512 Return to text ⤴

  49. https://droughtmonitor.unl.edu/data/png/20211207/20211207_va_trd.png Return to text ⤴

  50. https://droughtmonitor.unl.edu/data/png/20211207/20211207_northeast_trd.png Return to text ⤴

  51. https://www.wfxrtv.com/news/local-news/lynchburg-central-virginia-news/outdoor-open-burning-banned-in-amherst-county-until-further-notice/ Return to text ⤴

  52. https://droughtmonitor.unl.edu/data/png/20211228/20211228_usdm.png Return to text ⤴

  53. https://droughtmonitor.unl.edu/data/png/20220125/20220125_usdm.png Return to text ⤴

  54. https://droughtmonitor.unl.edu/data/png/20220125/20220125_usdm.png Return to text ⤴

  55. https://droughtmonitor.unl.edu/data/png/20220125/20220125_usdm.png Return to text ⤴

  56. https://droughtmonitor.unl.edu/data/png/20220125/20220125_usdm.png Return to text ⤴

  57. Climate normals, as defined by the National Oceanic and Atmospheric Administration (NOAA), are “three-decade averages of climatological variables including temperature and precipitation.” The latest climate normal released by NOAA is the 1991–2020 average. See https://www.ncdc.noaa.gov/data-access/land-based-station-data/land-based-datasets/climate-normals Return to text ⤴

  58. https://www.cpc.ncep.noaa.gov/products/predictions/long_range/seasonal.php?lead=2 Return to text ⤴

  59. For more information on how NOAA defines at, above or below normal and determines percent chances, see: https://www.cpc.ncep.noaa.gov/products/predictions/long_range/seasonal_info.php Return to text ⤴

  60. https://www.cpc.ncep.noaa.gov/products/predictions/long_range/seasonal.php?lead=2 Return to text ⤴

  61. https://www.cpc.ncep.noaa.gov/products/predictions/long_range/seasonal.php?lead=2 Return to text ⤴

  62. https://www.cpc.ncep.noaa.gov/products/expert_assessment/season_drought.png Return to text ⤴

  63. https://www.cpc.ncep.noaa.gov/products/analysis_monitoring/enso_advisory/ensodisc.html Return to text ⤴

  64. https://www.cpc.ncep.noaa.gov/products/analysis_monitoring/enso_advisory/ensodisc.html Return to text ⤴

  65. https://www.cpc.ncep.noaa.gov/products/analysis_monitoring/enso_advisory/ensodisc.html Return to text ⤴

  66. https://www.cpc.ncep.noaa.gov/products/analysis_monitoring/enso_advisory/ensodisc.html Return to text ⤴

  67. Romita Grocholski, Krista, Michelle E. Miro, Lena Easton-Calabria, Jessica Spaccio, Samantha Borisoff, and Arthur T. DeGaetano, Mid-Atlantic Regional Climate Impacts Summary and Outlook: Fall 2021. Santa Monica, CA: RAND Corporation, 2021. https://www.midatlanticrisa.org/climate-summaries/2021/12.html Return to text ⤴

  68. https://www.ncei.noaa.gov/products/land-based-station/us-climate-normals Return to text ⤴

  69. https://www.noaa.gov/news/new-us-climate-normals-are-here-what-do-they-tell-us-about-climate-change Return to text ⤴

  70. https://www.ncei.noaa.gov/products/land-based-station/us-climate-normals Return to text ⤴

  71. Romita Grocholski, Krista, Michelle E. Miro, Lena Easton-Calabria, Jessica Spaccio, Samantha Borisoff, and Arthur T. DeGaetano, Mid-Atlantic Regional Climate Impacts Summary and Outlook: Fall 2021. Santa Monica, CA: RAND Corporation, 2021. https://www.midatlanticrisa.org/climate-summaries/2021/12.html Return to text ⤴

  72. https://www.noaa.gov/news/new-us-climate-normals-are-here-what-do-they-tell-us-about-climate-change Return to text ⤴

  73. https://www.washingtonpost.com/weather/2021/05/04/noaa-new-climate-normals/ Return to text ⤴

  74. https://loca.ucsd.edu/ Return to text ⤴

  75. More information on RCP 4.5 can be found in: https://doi.org/10.1007/s10584-011-0151-4 Return to text ⤴

  76. More information on RCP 8.5 can be found in: https://doi.org/10.1007/s10584-011-0149-y Return to text ⤴

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