When it comes to broadcast meteorology, it’s never too early to begin networking. Matthew Cappucci—15 years old and perhaps the youngest person to give a presentation at an AMS conference—kicked off his talk at the 41st Conference on Broadcast Meteorology by noting he’d be ready for the workforce in six years if anyone was interested. His presentation on gust-front waterspouts was met with an enthusiastic response from the broadcasters and personal accolades from Harvey Leonard, chief meteorologist at WCVB-TV in Boston, who joked that Cappucci could have his job in less than six years.

As notable as Cappucci’s research and presentation was, more impressive is the fact that his work with the local NWS office in Taunton, Massachusetts, has resulted in them adding additional statements to their severe thunderstorm and special marine warnings. His goal is to have other offices adopt the new warning criteria and also have broadcasters use these parameters in alerting the general public regarding threatening weather, including gust-front related waterspouts.

Cappucci’s talk can be found here, and the AMS website now has recordings of numerous great presentations from the conference that took place in Nashville in June.  The meeting featured recent research in climate change, communication, and educational programs; a few of the presentations that got the conversation flowing among attendees were:

  • James Spann, broadcast meteorologist in Birmingham, Alabama, relayed his personal experience on the generational tornado outbreak of April 27 2011, noting that despite excellent warnings, the loss of life was exceptionally high and unacceptable. Being on traditional television and radio and using social media isn’t enough, he says; broadcasters need to use it correctly to be effective.
  • Sheldon Drobot of NCAR presented the development and testing of the mobile alert warning (MAW) application, which blends traditional weather information with mobile vehicle data to get current weather conditions and provides them to users through web and phone applications. His paper on MAW has recently been accepted to BAMS and will be published in an upcoming issue.
  • The panel session on “Naming Winter Storms” included the NWS’s stance by John Ferree, Susan Jasko’s communication perspective on the power involved in naming, and Bryan Norcross on The Weather Channel’s decision to name the storms and how they went about it.

Norcross also spoke on the “Lessons from Hurricane Sandy on Evacuation Communications,” exploring how the threat might have been better characterized to convey the possible expected coastal effects and resulting danger.

And if you want more from Cappucci, he also wrote an article on Hurricane Sandy for a local paper, which can be read here.  Not bad for someone who still has two years of high school to complete.

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A market research report released this month predicts that vehicle fleet management solutions, involving both software and hardware, will balloon from a $10 billion to a $30 billion industry within five years. The Dallas-based company Markets and Markets cites not only growing numbers of planes, trucks, cars, and ships, especially in Asia, but also several trends that tap the expertise of atmospheric scientists: “The environmental concerns, CO2 emission reduction norms, and fleet operators’ need for operational efficiencies are expected to serve as major drivers for the fleet management market.”

The report echoes the message of another report issued just a month ago by the market research firm, Technavio, which touted double-digit growth in the global intelligent transportation systems markets through 2016.

This can only be good news for a weather community that is already essential to fleet management in the aviation and maritime industries, right? Well, maybe. Especially in the area of smart surface transportation, the opportunities are huge, but everything depends on yet-to-be specified, rapidly evolving markets and technologies. This is a formative moment in that market–a drive-by opportunity. The chance to embed meteorological priorities in this burgeoning field–specifically, equipping vehicles to report key environmental variables to the meteorological community–may pass by quickly. Hence, several years ago an AMS Annual Partnership Committee on Mobile Observations was asked to “articulate a clear vision for mobile data that captures the immense opportunities for these data to improve surface transportation weather services.”

The resulting report is available on the web (here). However, in case you don’t have time to read all 88 pages there, or if you missed the multiple sessions on transportation at this week’s AMS Summer Community Meeting, you have another option. Read the shorter version of the report, by William Mahoney and James O’Sullivan, in the July issue of BAMS.

The article, “Realizing the Potential of Vehicle-Based Observations,” stresses that the involvement of meteorology in intelligent vehicle systems is not a given—our community has to be engaged in the broader technological efforts that are already underway.

Whether this opportunity is acted upon or missed (at least initially) will depend greatly on the weather community’s technical understanding and eventual adoption of … unique datasets and their level of participation in connected vehicle initiatives within the transportation community.

The stakes are obvious, both in getting real-time weather information to drivers and in getting that data into the hands of the atmospheric science community. More than 7,000 people are killed, and more than 600,000 are injured, annually in weather related accidents on the road. Meanwhile,

the availability of hundreds of millions of direct and derived surface observations based on vehicle data will have a significant impact on the weather and climate enterprise. The potential improvements in weather analysis, prediction, and hazard identification should have a large positive effect on all weather-sensitive components of the U.S. economy and the capability to sense the lower atmosphere at finer scales than traditional observation systems, which will improve the detection and diagnosis of extreme weather events that affect lives and property.

It’s no accident, then, that meteorologists are eyeing your car as the observing platform for this future transformation. Mahoney and O’Sullivan detail some of the possibilities:

Vehicle-based air temperature observations could provide additional temporal and spatial specificity required to more clearly identify rain/snow boundaries; also, antilock brake and vehicle stability control event data could support the diagnosis of slippery pavement conditions. Even the most common components of the vehicle can begin to tell a story about the near-surface atmospheric and pavement conditions through the intelligent utilization of vehicle data elements, such as windshield wiper state, external air temperature, headlamps, atmospheric pressure, sun sensors, vehicle stability control, and the status of an antilock breaking system.

For all the benefits of vehicle-based observing networks, however, there are significant challenges. For example, Mahoney and O’Sullivan note, “Traditionally, near-surface weather observations have been generated by stationary platforms. Taking observations from mobile platforms, particularly passenger and fleet vehicles, introduces new dimensions of complexity.” In addition, among other obstacles:

Many of the normal concerns associated with dedicated weather sensors—siting, maintenance, and calibration—are exacerbated with mobile sensors, especially when large numbers are to be sited on a wide variety of vehicles driven by people with varying interest in those sensors. The best place to site a temperature sensor on a particular model of car may not be the best location for a pressure sensor, and the best place for a particular sensor on one model of car might not even exist on another model.

Beyond the hopes of placing dedicated weather sensors on cars, there are, of  course, existing engine sensors and weather-related vehicle behavioral data:

This type of information could be made available quickly without deployment of new sensors, it is considered to be the “low-hanging fruit” of mobile weather sensing. However, it presents some very challenging calibration issues and may ultimately not provide consistent enough information for weather applications.

There are also communications challenges: one intelligent transportation solution that is gaining traction involves direct, dedicated short-range vehicle-to-vehicle communications links between cars sharing the road. The weather community, by contrast, will require longer-range communications solutions to gather information from vehicles; somehow short-range, on-the-road links will need to be integrated with other options such as existing cellular networks creates new challenges .

Meanwhile, there are not just technical but also fiscal and institutional—perhaps legal and regulatory—barriers to successful implementation of the roadway network goals. The report emphasizes that there are solutions to these barriers, even though “a litany of barriers…may leave … the impression that mobile weather observing is too difficult, too costly, or otherwise too problematic to achieve on any useful scale.”

The institutional barriers make plain why improving forecast services for transportation was a vital one for consideration during the high-level considerations at the AMS Summer Community meeting, and by all of us in the weather and climate community. Mahoney and O’Sullivan show that the challenge of emerging roadway systems is an opportunity to shape development of the weather community and how it works:

Management of highways and the traffic they carry involves a large number of active participants, including the federal government, states, counties, municipalities, and regional authorities. In addition, the immature nature of road weather management offers numerous opportunities for entrepreneurial innovation, opening the door for commercial entities with potentially unconventional approaches to deploying mobile weather sensors and managing and exploiting the data from those sensors. At this point, it is not clear that, with all the various participants with their differing needs and agendas, the mobile weather observing enterprise is manageable in the normal sense of the word. In any case, there is no overall authoritative vision for the deployment, operation, management, and governance of mobile weather observing capability, let alone a high-level strategy, concept of operations, or implementation plan.


by James Stalker, President and CEO, RESPR, Inc.

Editor’s note: Because this column has triggered much discussion in the community already, it is important to emphasize that all posts on this blog–guest columns or otherwise–present the opinions of the authors only. These blog posts do not represent official policy or views of the AMS or of its membership. What follows are an individual’s thoughts, and we hope that others in the community recognize, as does Mr. Stalker, the value of open discussion.

The U.S. weather and climate enterprise is exemplary to many nations of the world. And yet, it appears to struggle to maintain its edge—especially in economic development, job creation, and producing constant weather-readiness throughout the nation. While dwindling public funding may be partially to blame, the problem is deeper.

What systemic issues might be holding the enterprise back? Is there unhealthy competition between sectors?  Can we avoid a slowing rate of growth within the weather and climate enterprise? How can we make the enterprise more vibrant and help it stay vibrant? It is important to consider such questions, especially now as we prepare for the AMS Community Meeting this week in Boulder, Colorado.

Sectors and their objectives

Government, academia, and the private sectors all provide products and services to a fourth sector—the users. This user sector is the most important of all, and its members must far outnumber those of the other sectors in a healthy enterprise.

Each sector has a different mission. For example, government mainly provides timely weather and climate information to citizens in order to save lives and minimize property damage. The government sector, secondarily, provides weather and climate information to the academic and private sectors to indirectly support education, research, and economic development. Additionally, the government engages in research and educational efforts itself.

It is fair to ask whether or not the government sector adequately fulfills its primary objective. Huge gaps exist in the weather and climate information available in the public domain today, and there are inabilities to adequately customize data to meet the disparate needs of the citizens. However, the government sector does provide information critical to the academic and private sectors. The fact that the government sector seems to do better in achieving its secondary objective, relatively speaking, than its primary objective suggests that something does not work well.

The primary objective of the academic sector is to educate our future scientists and technicians. Secondarily, it offers products and services to the other sectors. Strengthened weather and climate datasets from a refocused government sector would improve the academic sector’s success in its primary and secondary objectives. A refocused government sector would similarly benefit the private sector in developing better value-added products/services for users. The beneficiary shareholders come from all walks of life, of course, but primarily it is the satisfied customers—the users—who keep the private sector alive and well.

Pathways for Products

Curiously, the “free” weather and climate data model of the government sector can potentially lead to the unsustainable situation in which product and service providers outnumber users. We see this by looking at the various pathways by which weather and climate data product and service providers interact with one another and reach out to the user sector.

Schematic showing various pathways amongst four sectors. Schematic showing various pathways amongst four sectors.


All the pathways shown above are currently utilized in one way or another. In the current weather and enterprise structure, Pathway 1, by which the private sector reaches out to the user sector, is competing against Pathways 2 and 3, where the government sector and the academic sector, to a lesser degree, offer “free” data products to the user sector. Even though the private sector provides value-added products, the user sector is made to believe that they can get similar weather and climate products from the government and academic sectors for free. Secondly, since the government sector is focusing on Pathway 2, its production of a strong foundational data for Pathway 1A receives minimal attention.

Even though Pathways 1 and 3 don’t necessarily compete with one another, at least not as apparently as Pathways 1 and 2, the academic sector could increase its effectiveness by focusing its scarce financial resources on education and academic research.

The status quo enterprise structure results in unnecessary road blocks for the enterprise as a whole.

The vitality of the enterprise would get a boost if the government sector reversed its priority of objectives and emphasized, instead, on providing critical weather and climate information to the private (Pathway 1A) and academic (indirectly to Pathway 1B) sectors. At the same time, the academic sector would make a positive contribution to the vitality of the enterprise by shifting focus on improving and providing weather and climate information through academic research to the private sector (Pathway 1B). Both Pathways 2 and 3 would become secondary objectives in the new sectoral coexistence illustrated here.

This suggests that a business model aimed at providing “free” weather and climate information, while appealing, is not sustainable and will lead to inferior products. This model puts the private sector at a severe disadvantage.

The whole weather and climate enterprise will have to realize this fatal flaw. The government sector should ask itself: “Would it be better to invest more of the taxpayer dollars in what the government sector does better than in what it does not do so well?”

With this adjustment, the private sector will become the chief provider of end-user products and services to the user sector directly. This would not necessarily mean the end of Pathway 2, however. For example, the government might wonder if some users would be unable to afford the value-added products/services provided by the private sector. In this case, instead of trying to produce end-user products/services itself, the government sector would be better off purchasing them from the private sector and making them available to those users who are in need of the value-added products/services. In other words, certain segments of users may receive value-added products indirectly from the private sector.

A Path to Consider

Leaders engaged in weather and climate products and services from the three sectors should get together and evaluate the merit of this adjustment of priorities. The government sector would share with the other sectors; its effort would be appropriately split between strengthening the foundational weather and climate information and directly reaching out to the user sector. An oversight committee, sponsored by AMS, could ensure continued implementation of this new adjustment within the weather and climate enterprise. This committee would come up with further adjustments to the enterprise structure.

It is necessary practice in business, government, and academia alike to continually reexamine priorities to ensure economic vitality in a changing society and changing markets. The weather and climate enterprise should be no exception.



by Paul Higgins, AMS Policy Program Director

In June, President Obama gave a long-anticipated speech laying out his vision for climate change risk management. The centerpiece of the approach is to use the EPA to regulate greenhouse gas emissions from power plants. What those regulations will look like remains unclear, but the President’s intent to reduce emissions significantly, particularly from coal-fired power plants, is clear.

By all accounts, this wasn’t the approach the president wanted to take for climate change. He has said repeatedly and throughout his presidency that he favors a bipartisan solution that comes from Congress. After nearly five years and with the end of his second term approaching, the president appears to have concluded that the political divisiveness surrounding climate change makes congressional action unlikely.

How well the president’s approach will work is hard to know, of course, but it will be particularly interesting to see how this unilateral effort affects the politics of climate change risk management. There is a chance that the president’s plan will ultimately reduce the political divisiveness surrounding climate change, in part, because the approach itself is politically divisive.

Using the EPA to regulate emissions will not go over well with many in Congress. His opponents will likely find it easy to criticize, and score political points in so doing, on both philosophical grounds (i.e., based on a preference for less intrusive federal intervention) and because unilateral executive action is less democratic than including Congress in the creation of a new law. But the very fact that substantive arguments can be made for different approaches may provide an incentive for his opponents to develop and offer those alternatives. That could create an important opening that’s been largely missing for climate change over the last few decades.

Prior to the 1990, Clean Air Act Republicans and Democrats could more easily agree on an environmental problem yet disagree on the solution. Republicans tended to prefer market-based solutions while Democrats tended to prefer command-and-control regulation. Conservative philosophy convincingly won that debate because the market-based approach used in the 1990 Clean Air Act proved far superior as a tool for protecting the environment and maximizing the economic benefits of doing so.

Perversely, that philosophical victory for conservatives has made it harder for the two parties to agree on climate change risk management. There isn’t an easy way for the parties to distinguish themselves if they agree on the basics of the solution. Instead, the political incentive has been to disagree about whether there is a problem in need of a solution in the first place. Once the champions of climate policy coalesced on a conservative approach for addressing climate change, the choice for everyone else became too stark: go along with that approach or oppose climate policies altogether. If there isn’t middle ground and your opponent is for it, then few options are more politically effective than being against it.

Of course, the politics of climate change are, and will likely continue to be, challenging for other reasons, most notably because of the competing and incompletely reconcilable interests of those affected by policy options. But there is a wide range of potential solutions for helping to manage climate change risks. Critically, there is a policy option for virtually any political philosophy out there. For example, Congress could use a market-based approach to reduce greenhouse gas emissions while simultaneously using every penny that the government raises through such an approach to reduce existing taxes on wages, corporate income, or capital gains. The reduction in taxes that would result would be a major victory for conservatives that many Democrats could plausibly go along with. Yet such options haven’t been developed or seriously considered.

That a broad range of potential risk management strategies hasn’t been developed and explored by policy makers is a major breakdown in our policy process. That policy deliberations (and public debates) about climate science are routinely at odds with the assessments of the relevant subject matter experts is a major failure of our national dialogue on the topic.

These failures have resulted, in part, because the political incentives for developing and exploring policy options have been too weak. By moving to circumvent the current political impasse to climate policy through a unilateral approach (particularly one likely to face sharp political opposition), the president may create a new opportunity for a broader consideration of options. If that happens, whether or not the president’s proposed solution is sufficient, he may help to depolarize the politics of climate change and spur the consideration of new and meaningful approaches to climate change risk management.

AMS Policy Program Director Paul Higgins’s perspectives, including this column, will be appearing regularly in the Bulletin of the American Meteorological Society.

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The July issue of BAMS includes a feature on the new and improved imaging capabilities of the Visible Infrared Imaging Radiometer Suite (VIIRS), one of the five instruments aboard the Suomi NPP satellite. The cover montage highlights VIIRS’s expanded spectral aptitude and microscale resolution by depicting july_bams_coverthree different perspectives on the tornado outbreak that swept across the Midwest on May 20, culminating in detailed nighttime evidence of the track of  devastation in Moore, Oklahoma, as detected on May 21.

That month, the instruments on Suomi NPP were being calibrated by aircraft that in many cases flew directly under the path of the satellite. On May 20, one of these planes–an ER-2 flying above the cloud cover at approximately 65,000 feet–used the MODIS/ASTER Airborne Simulator (MASTER) to capture images of the storm that brought the EF5 tornado to Moore. The image below shows the tornado system minutes before it reached the city, and is overlaid on a Google Earth map to show the tornado location.

oklahomazoom2 (Image credit: Google Earth/Ames Airborne Sensor Facility/Rose Dominguez)

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Philip Ardanuy and Eileen Shea, the co-chairs of the 2014 AMS Annual Meeting, and AMS President J. Marshall Shepherd recently sent out this message with updates about the meeting:

Dear Colleagues and Friends of the AMS,

We are happy to announce that most of the conferences have decided to extend their abstract submission deadline. You can view all of the call for papers and updated abstract deadlines here.

Additionally, registration rates have been posted on the AMS 94th Annual Meeting web page and links to register for the conference are now active.

The preregistration (discounted registration) deadline this year is:

2 December 2013

Please remember that ALL attendees must register in order to attend and present at the conference. Registration is separate from the abstract submission fee.

Hotel reservation blocks will open and links to make those arrangements will be available on 5 August.

Thank you in advance for booking at an AMS-contracted hotel, since revenue from sleeping rooms helps offset other meeting costs and is passed down to attendees in keeping registration rates to a minimum.

Thank you and see you in Atlanta!


Phil Ardanuy and Eileen Shea

Co-Chairs, 2014 AMS Annual Meeting

J. Marshall Shepherd

AMS President


by James Stalker, President & CEO, RESPR, Inc.

Since my last blog in The Front Page a little over a year ago about the effort to form a National Network of Networks, many changes have taken place.

First, the AMS NNoN ad hoc Committee completed its final report in 2013, which is available on the AMS website at http://ametsoc.org/boardpges/cwce/docs/NoN/2013-06-01-NNoN-Final-Report.pdf. A short summary article will appear in the Bulletin of the American Meteorological Society this fall.

While these are welcome developments, the network of networks initiative almost came to a screeching halt except for the work of the Weather and Climate Enterprise Commissioner, Matt Parker, who didn’t want it to go away. Matt asked me to chair the new Nationwide Network of Networks (NNoN) effort going forward. At that time, as the NNoN R&D/Testbeds Working Group chair for the previous three years, I was prepared for the seemingly inevitable end of the NNoN effort, but refused to accept it.

So, here we are now with renewed enthusiasm for the new NNoN initiative taking shape within a full fledged AMS NNoN Committee, under the AMS Board on Strategic Topics (BEST). Previous participants, particularly John Lasley, and the past NNoN ad hoc Committee chair, George Frederick, pooled together a committee of more than 30 people to resume the effort.

For those of you who are not familiar with the NNoN initiative, it all got started when the National Research Council (NRC) report titled Observing the Weather and Climate From the Ground Up: A Nationwide Network of Networks came out in 2009. The AMS NNoN ad hoc Committee further reviewed the recommendations of the NRC report and produced the aforementioned report of its own.

The ad hoc committee produced six specific recommendations, but the first and most important one is to organize a stakeholders summit to gain weather and climate community-wide support for the NNoN effort. The renewed NNoN initiative is, in fact, considering this recommendation in stride. It will hold a couple of mini-summit meetings in 2013 and 2014, before the culminating stakeholders summit in 2015.

In this regard, a meeting is scheduled to take place in Boulder, Colorado, on Monday, August 12, the day before the AMS Summer Community Meeting begins. Members of the weather and climate enterprise community are urged to attend this mini-summit to learn about the new NNoN direction and provide critical input.

One of the key tweaks in the approach of the new NNoN is the bottom-up approach, as opposed to the top-down approach of the earlier efforts. In other words, new network members joining the NNoN are consulted for their input before recommendations are suggested specifically for that network member. Another key tweak is that the new NNoN Committee is going to actually help network members implement the network-specific recommendations. Implementation services will require funding, and the new NNoN is exploring many possible ways to secure such funding.

The new NNoN effort is supported by three working groups: 1) an Implementation Working Group, 2) an Outreach Working Group, and 3) an Advisory Working Group. These working groups comprise multiple teams to provide the benefits network members are looking for. The upcoming BAMS article will detail the new NNoN initiative, including the working groups and the teams that comprise them.

Also, for further information and for expressing your interest to join the effort as a committee member, get in touch with me at jrstalker@respr.com or any of the three working group chairs (Greg Partt at greg.pratt@noaa.gov; John Lasley at johnlasley2007@gmail.com; Don Berchoff at Donald.Berchoff@unisys.com).


Philip Ardanuy and Eileen Shea, the co-chairs of the 2014 AMS Annual Meeting, and AMS President J. Marshall Shepherd recently sent out this message about submitting abstracts for the meeting:

Dear AMS Colleagues,

It’s hard to believe that we’re already actively gearing up for the 2014 AMS Annual Meeting, to take place 2-6 February 2014 in Atlanta, Georgia! With this year’s theme: “Extreme Weather—Climate and the Built Environment: New Perspectives, Opportunities and Tools,” we’re confident that you’ll find lots of interesting, thought-provoking, professionally rewarding, and personally satisfying interactions. Recent events like Superstorm Sandy, the Oklahoma Tornadoes, and flooding in Calgary highlight the importance of the meeting theme, which is increasingly relevant to the science and operational communities, and society as a whole. The theme combines scientific inquiry, technological advances, societal implications, and public awareness through the lens of past, current, and future extreme weather and climate events.

This note is to remind you that the deadline to submit an abstract is fast approaching: 1 August 2013.  Check out the AMS 94th Annual Meeting Web Page: http://annual.ametsoc.org/2014/. Here, you can find more details on the Annual Meeting theme as well as links to the Call for Papers for each participating conference, and links to submit your abstract online. All other information pertinent to the meeting will be posted to that page as it becomes available.

An abstract fee of $95 (payable by credit card or purchase order) is charged at the time of submission (refundable only if the abstract is not accepted).  The abstract fee includes the submission of your abstract, the posting of your extended abstract, and the uploading and recording of your presentation to be archived on the AMS website. For poster presenters, you will also be able to submit a PDF file of your poster presentation for online viewing. Authors will be notified of acceptance by the beginning of October.

Even if you choose not to submit an abstract for the 94th AMS Annual Meeting, we hope you will come to listen, discuss, learn, and connect with colleagues. Continue to check out the AMS Annual Meeting website for new information on themed joint sessions, scientific and technological presentations, opportunities for social interactions, short courses, exhibiting details, registration, hotel and local area information, and much more.

Be sure to also follow Annual Meeting developments on The Front Page.

See you in Atlanta!


Philip Ardanuy and Eileen Shea

Co-Chairs, 2014 AMS Annual Meeting

J. Marshall Shepherd

AMS President


With data compiled from a number of satellite, aircraft, and surface-based surveys, the recently completed Bedmap2 project comprises three datasets to map the ice-covered continent of Antarctica: surface elevation, ice thickness, and bedrock topography. The new dataset updates 2001’s original Bedmap compilation with tighter grid spacing, millions of additional data points, and extensive use of GPS data—enhancements that have improved the dataset’s resolution, coverage, and precision. For example, it depicts many surface and sub-ice features that were too small to be visible in the original Bedmap. Data from Bedmap2 reveal that Antarctica’s average bedrock depth, deepest point, and ice thickness estimates are all greater than that recorded in the original Bedmap.

As outlined in the NASA video below, the updated information obtained from Bedmap2 should enhance currently limited data on the continent’s ice thickness and what is beneath the ice, which could help researchers better understand how Antarctica will respond to a changing climate. It also “will be an important resource for the next generation of ice sheet modelers, physical oceanographers, and structural geologists,” according to the British Antarctic Survey’s Peter Fretwell, lead author of a recently published article on Bedmap2 that appeared in The Cryosphere. The article and Bedmap2’s data can be accessed here.


As Gettysburg National Military Park commemorates the 150th anniversary of the momentous and bloody battle fought there (it took place July 1-3, 1863), we can look back and examine the role weather played in those three days of conflict (and AccuWeather already has, in this interesting post). This is possible thanks in large part to a local man, Rev. Dr. Michael Jacobs, who took weather observations three times a day, even as the fighting raged on around him. His notes, which can be seen here, show that temperatures were slightly below average for all three days, and that cloud cover was considerate much of the time. This benefited the soldiers, who would have been most uncomfortable in their wool uniforms during extreme heat and/or humidity. Late on July 3, a thunderstorm broke out, and it is testament to the ferocity of the battle that Jacobs noted the thunder “seemed tame” after the nonstop cacophony of gunfire that echoed throughout that afternoon.

As the battle wound down, the weather intensified, with rain falling throughout the day (a total of 1.39 inches, according to Jacobs) on July 4, the day after the combat had ended. The inclement weather turned out to be significant, as some wounded soldiers were still lying on the battlefield; tragically, those who were in low-lying areas drowned when the rainfall caused the Plum Run Creek to overrun its banks. The rains also added insult to injury for the retreating Confederate army–the dirt roads they traveled on rapidly became treacherous, and as they moved southward they were trapped for a period of time on the north side of the Potomac after the river swelled, making it temporarily impassible. They weren’t able to cross until July 13th.