The weather continues to calm down along the I-95 corridor as the first Nor'easter of the season exits into the North Atlantic. High pressure will then briefly build across the Northeast for the first half of the weekend. This will lend to a mainly clear Friday night and result in a cold start to Saturday. In fact, many locations away from the immediate coast may see their first frost. Here is a look at forecast temperatures for 8 AM Saturday. Plenty of 30s, especially just outside of the big cities.
Courtesy Pivotal Weather
We'll quickly shake the morning chill with lots of sunshine expected for Saturday. The afternoon looks fantastic and seasonably mild. Check out the anticipated 3 PM temperatures for Saturday.
Courtesy Pivotal Weather
Beyond that, the forecast turns a bit sour. The remants of Tropical Storm Nestor will be sliding up the East Coast on Sunday. This, combined with a weak disturbance will lend to an unsettled second half of the weekend for much of the Northeast. Clouds will increase Saturday night and we'll look for showers and even a few periods of rain to develop on Sunday. Folks from Washington, DC to New York City will have the highest threat for rain on Sunday, but a few showers will at least be possible all the way up to Boston. Here is a look at what the radar may look like around 2 PM Sunday.
Courtesy Pivotal Weather
Rainfall amounts will vary quite a bit from north to south. Here is a look at how much to expect through Sunday night.
Courtesy Pivotal Weather
Finally, here is the latest track for Tropical Storm Nestor as of 5 PM Friday from the National Hurricane Center. Again, while the center of the storm is forecast exit off the North Carolina coast, some of the moisture associated with it will stretch north along the I-95 corridor.
September 2019 was a month to remember with drastic extremes in terms of temperature and precipitation from Chicago to the Ohio Valley. This was due to a large area of high pressure centered over the eastern United States, while a troughing (stormy) pattern set up over the West. This allowed multiple fronts to push through the Chicago area leading to above average temperatures and frequent flooding rains, while areas in the Ohio Valley saw abnormally dry conditions and record heat. Overall, Chicago O’Hare airport came in 1 – 2 degrees above normal with an average temperature around 77 degrees. Flooding rainfall caused more than double the average of amount of rainfall for the month, with 7.61” of rainfall recorded! The average for September is only 3.21”! The opposite occurred for Indianapolis, Columbus, Dayton, and Cincinnati. These areas came in 8 – 10 degrees above normal, with multiple stretches in the lower to middle 90s! This record heat was accompanied by abnormally dry conditions with these same locations only experiencing less than 1” of rain! To put this extreme difference into context, see the precipitation map below.
Courtesy Midwestern Regional Climate Center
Heading into the first week of September, the weather in the Midwest was fairly seasonable with average temperatures ranging in the 80s. A front passed through the Chicago and the Ohio Valley, with Columbus and Dayton picking up around a half inch of rain. This same front did produce a bout of severe weather in Chicago along with some wind damage around Waukegan, WI. Meanwhile, warm and dry weather (5-15 degrees above normal) continued across the Ohio Valley. The Chicago area warmed up heading into September 10th-13th, with a daily high of 90° on the 10th, while areas towards Dayton, OH topped out 93-95°. While it wasn’t a daily record in Chicago, Cincinnati and Columbus broke their record high temperature on the 11th and 12th from back in 1952, with a high of 95° and 93° respectively. This hot and humid weather set the stage for a strong cold front that pushed through Chicago, particularly in Lake and McHenry counties where localized areas saw up to 5-6” of rain. This rainfall fell over a short period of time causing widespread flash flooding and moderate river flooding near the Fox and Rock Rivers. If the flooding wasn’t bad enough, this front also produced some severe storms which resulted in downed trees and branches as winds gusted upwards of 60 mph. This initial batch of precipitation would “prime” the region for flooding for weeks to come. Quieter weather briefly returned across much of the Midwest into the third week of the month. It was warm as well with temperatures running 7-14° above normal from Indianapolis to Columbus. The combination of no precipitation and well above normal temperatures caused the region to turn abnormally dry with areas southward toward Dayton and Cincinnati observing near moderate drought (see figure below).
Courtesy National Drought Mitigation Center
The last 10 days of September went out with a bang with torrential rainfall redeveloping across the Chicago area, while areas to the east remained hot and dry with only bouts of minor storms that only led to only a few tenths of an inch of rain. From the 21st to the 23rd, torrential rainfall crushed the Windy City with 1.5 – 3.0” of rain. This, coupled with saturated grounds from previous rainfall resulted in widespread stream and river flooding. On the opposite side of the coin, the Ohio Valley remained 10-20 degrees above average for this time of year exacerbating the drought for the region. Unfortunately, Chicagoland got rocked again with heavy rains and severe weather on the 28th and 29th. Hail and damaging winds blew through the southern half of the region, particularly just south of Aurora and Joliet. The rainfall amounts were substantial once again, with upwards of 3 - 5” south of the metro. For Indianapolis to Columbus, the hot weather persisted as high temperatures reached the upper 80s to mid-90s! Overall, it was a September to remember across the Midwest. The average temperature in Cincinnati, Columbus and Dayton was 75.4°, 72.8° and 73.8° respectively. For Dayton and Indianapolis, this was the warmest September on record. Cincinnati and Columbus had their 2nd hottest September since 1881! September ended up 6th wettest month and the wettest since 1871!
As you may expect, September as a whole featured a stark contrast in record rainfall and warm/dry conditions across the Midwest. Take a look at the table below:
By this time in 2018, the Northeast and Mid-Atlantic finally started to depart a stretch of unbearable heat and humidity. However, in September 2019, the region was on the opposite side of the spectrum, at least in terms of precipitation and active conditions. This year, September ended up on the warm side, but it sure was rather quiet for long stretches of time, giving us a break from severe weather. Well, sort of, at least after the initial few days. The first week of September saw two frontal passages that triggered squall lines and even a few tornadoes! The first was on the 2nd which brought healthy rainfall across New England (over an inch in Boston) and an EF-0 tornado late in the afternoon in Manorville, NY on Long Island. Fortunately, damage was limited to trees given the rural area the tornado touched down. A second tornado occurred on September 4th and trekked across Coventry, CT. This tornado was stronger, clocking in as an EF-1 and produced some minor damage to buildings along with snapped and uprooted trees. Here are a few links about the Connecticut tornado on September 4th.
— NBC Connecticut (@NBCConnecticut) September 5, 2019
National Weather Service: Tornado touched down in Coventry, Mansfield
— thechroniclect (@thechroniclect) September 5, 2019
Coventry is apparently the new tornado hot spot in CT. Nick Stanczyc grabbed this shot on 7/10/2013 as a tornado moved through Coventry. Yesterday's tornado was a couple miles north of that one. #nbcct pic.twitter.com/1pUnKVHc7J
— Ryan Hanrahan (@ryanhanrahan) September 6, 2019
The rain that some locations saw from these two disturbances would not be matched for essentially the rest of the month as the pattern prevented any real moisture from sticking around. By the second week of September, most eyes were focused on Hurricane Dorian. After wreaking havoc across the Bahamas, the hurricane turned north and moved parallel to the southeast coast of the U.S. Dorian then accelerated northeast into the open Atlantic, but passed close enough to southern New England on September 6th to produce some gusty winds and rainfall. Here is a look at the waves that Dorian produced off of Long Island.
— WCBS Newsradio 880 (@wcbs880) September 6, 2019
Successive high pressure systems then dominated the rest of the month with occasional, but brief interruptions from rain. Temperatures see-sawed as a result, but did favor the warmer side of trends. There was one push of true cool Canadian air by the third week that sent high temperatures into the 60s and 70s while at night it cooled well into the 40s and 50s, including some 30s across the interior Northeast! At the same time, not a single drop of rain had fallen. High pressure stayed anchored of the Northeast the entire time until September 23rd when it began to shift offshore. A return flow then developed out of the southwest for the remainder of the month, which pushed temperatures back into the 80s and 90s across the region. Temperatures generally ended up 10 to 20 degrees above normal, marking the warmest part of September. Other than the first week of the month, September was basically a quiet one overall, without too much fanfare. Temperatures finished 3 to 6 degrees above normal across the board. In fact, it was the warmest September on record in Baltimore, MD breaking the old mark set in 1970. Lack of precipitation was the bigger story as the region barely received tropical moisture that usually falls at this time of year. In fact, New York City and Philadelphia both saw their top 10 driest months, while Baltimore had its driest on record since 1967 only receiving 0.16" of rain!
We have reached the peak of hurricane season and of course the big story over the last two weeks has been Hurricane Dorian (picutred above via College of Dupage NEXLAB). The storm peaked as a Category 5 hurricane on September 1st when sustained winds reached 185 mph and the pressure fell to 910 millibars. Unfortunately, Dorian caused catastrophic damage in the northern Bahamas with many fatalities. The storm weakened as it moved away from the Bahamas, but still caused major impacts from the east coast of Florida to the Outer Banks of North Carolina. In total, the early estimates have Dorian incurring over 7 billion in damage.
Meanwhile, we had a short-lived tropical storm named Fernand that made landfall in northern Mexico on September 4th and dropped excessive amounts of rain. Elsewhere, Tropical Storm Gabrielle continues to meander over the northern Atlantic, but is expected to dissipate by midweek.
Looking ahead, the National Hurricane Center is watching a few areas of interest between Africa and the Caribbean for potential tropical development. Again, this is prime time for the tropics, so it’s likely that we have another named storm to track by the middle of September. The next name on the list is Humberto followed by Imelda.
So far this season, we have had seven named storms, two of which became hurricanes including the one major (Category 3 and higher) which was Dorian. The hurricane season ends on November 30th.
Not So Fast According to the Weather Experts!
As the calendar transitions into the fall season, our meteorologists at WeatherWorks are focused on the efficiency in preparation and delivery of our Certified Snowfall Totals (CST)® service to our clients. In today’s world of instant gratification from social media platforms to Amazon Prime delivery for shopping, we are often confronted with the same request… can’t we have the totals within 24 hours? The quick answer is obviously yes, however, it's not that simple. The true solution involves the accuracy and integrity of our service, which your billing process heavily relies on.
Sure, there are times when some reliable data is available immediately after the storm, but in order for WeatherWorks to remain the industry leader in providing accurate and reliable snow / ice verification to over 3,000 clients, the certification process always requires more than the desired 24 hours. Internal research indicates that WeatherWorks maintains an astounding 0.10% (one tenth of a percent) discrepancy rate out of 390,000 reports delivered during the 2018-19 season. A discrepancy is defined as a total that required an adjustment after being published due to further research. It is fair to assume that number would be exponentially higher with 24 hour published reports.
The first problem with the 24 hour methodology is simply due to the data that is available. Don’t risk your company’s reputation by utilizing inaccurate totals! Figure 1 below shows you a timeline of the available data. If CST reports are published in 24 hours you WILL be missing some of the more reliable observations and totals. Second, it takes time to extensively review and document the entire storm from start to end. The scientific review process that our professional meteorologists employ would be inherently rushed. Even the more "reliable" airport measurements that report their total immediately following a storm have often been revised more than 24 hours after the storm, which can result in hundreds if not thousands of dollars in billing differences.
When our meteorologists create our Certified Snowfall Totals® reports, they collect, analyze and quality control a vast array of data from various public and private sources which include but are not limited to: our own snow spotters, NOAA official storm spotters, airport measurements (ASOS), Cooperative Observers, government agencies, colleges / universities, social media platforms and online forums. This data is then analyzed for spatial and temporal consistency using both objective tools (RADAR, web cams, liquid equivalents, contouring algorithms) and subjective measures (terrain, elevation), ensuring no biased observations are included in the analysis. Finally, the quality controlled dataset is used to generate snow or ice totals at a ZIP-code level.
WeatherWorks may not assure you the fastest totals in the industry, but you and your clients can rest easy knowing that our Certified Snowfall Totals® service left no stone unturned. We will leave you with accuracy above all else backed by our double check certification process. As always, we encourage you to contact us at 908-850-8600 anytime you have a question or concern.
While August is usually a step down from the severe weather, it certainly ended up more active than normal. Just to give an example, by the 22nd, we had already seen 16 days of severe weather which is abnormal even for that time of year. And the heat continued as expected but thankfully the humidity was not as high as last year’s swelter. Let’s see how the last month of meteorological summer panned out.
A boundary lingered just off the coast to start the month, but high pressure dominated the Northeast for the first few days of August. Temperatures were generally up to 5 degrees above normal for the period, which put much of the region into the 80s. As a cold front approached, humid air surged back into the region by the middle of the week providing the Mid-Atlantic and Northeast with a vigorous severe weather day on the 7th. Numerous storms resulted in wind damage across every state as well as three tornadoes (all EF-0’s) across New Jersey (which has had an abnormally high number of tornadoes this summer). The heavy rain also totaled over an inch across most of the I-95 cities as well.
— Ted Prohowich, Jr. (@Ted_Prohowich) August 15, 2019
The following week’s pattern waffled between high pressure and the occasional stalled front. By the middle of the month, the upper level pattern allowed for a sultry air mass to take over which sent temperatures as much as 10 degrees above normal, into the 80s and 90s. These conditions were ripe for violent storm days, particularly on the 18th and 22nd. On the 18th, several storms produced quarter-inch sized hail in eastern Pennsylvania and New Jersey. The 22nd was more localized with t-storm activity however, one storm in particular trekked across northern NJ through Long Island, which caused extensive damage. Numerous trees were uprooted and some buildings even partially destroyed. There were also a multitude of power outages that lasted into the next day.
Incoming storm on August 18th in NYC from meteorologist Matt Wunsch.
Sweet relief came on the 23rd when a cold front brought the first true “cool” Canadian air mass since spring. Temperatures crashed into the 70s, giving the Northeast quarter of the U.S. tastes of fall when some inland locations fell into the 40s at night! This kind of air mass also kept the weather rather quiet, but the 28th was the exception as a cold front and tropical disturbance offshore interacted with each other. While Tropical Depression Erin remained off the coast, a plume of tropical moisture triggered heavy rainfall across eastern New England (up to 1.5-3” of rain). Quiet weather then rounded out the month.
At this point, the keen observer is likely noting how quickly the days are diminishing now that we are well past the peak of summer. And indeed, cold fronts themselves are beginning to successfully push in cooler air now that subtle but noticeable changes are taking place as we enter autumn. The brief warm-up did push the month above normal, but not by much (0.5-2 degrees on average). Baltimore, MD did see its 9th warmest August on record, but most other places were nowhere near record-breaking. A few days between the 19th and 22nd did peak in the mid-upper 90s, with Baltimore, MD and Washington, D.C. hitting 98 and 99 degrees, respectively. Precipitation was more or less average even with Erin’s moisture late in the month.
If you're a regular viewer of weather broadcasts, you’ve probably heard this from a TV meteorologist: “overcast conditions are expected as a warm front approaches from the south.” Or: “showers and thunderstorms will occur today as a cold front slides through the region.” Usually, when a front approaches, cloudy skies along with precipitation are associated with it. But have you ever wondered how these weather fronts tick?
Basically, a weather front represents a boundary between two different air masses, such as warm and cold air. If cold air is advancing into warm air, a cold front is present. On the other hand, if a cold air mass is retreating and warm air is advancing, a warm front exists. Otherwise, a stationary front is present if the cold air is neither advancing nor retreating from the warm air mass.
In a cold front set-up, the boundary between the cold and warm air masses is relatively steep (see below), typically causing the warm air in front of it to rise rapidly. This rising air creates energetic, billowing cumulonimbus clouds leading to showers and thunderstorms. After the cold front passes, skies typically clear rapidly and temperatures cool due to the advancing cool air.
With a warm front, boundary between warm and cold air is more gradual than that of a cold front, which allows warm air to slowly rise and clouds to spread out into gloomy, overcast stratus clouds. Precipitation ahead of a warm front typically forms into a large shield of steady rain or snow. After the warm front passes, fair and milder weather is typical, however, a cold front is likely not far behind.
A front’s strength can be assessed by the difference in temperatures between the two air masses or temperature gradient. Basically, the larger the temperature gradient (as in 30s on one side and 60s on the other) the stronger the front is (example of a strong front above). Of course, a stronger front leads to a greater potential of precipitation, while a weak front may only bring a few clouds, a decrease in humidity, and/or a shift in winds. Fronts are also associated with low pressure systems, which you can learn more about here.
Also be sure to check out our YouTube Channel for weekly weather updates and our latest thinking on the Winter Forecast for the 2019-20 season. In fact, here's the second preview!
Clouds are described by almost every adjective in the book, from pretty to ugly to ominous and breathtaking. Did you know that different clouds are precursors to specific types of weather? It's true! Making note of the cloud types can give you insight into impending weather conditions. Let's learn more about the different cloud types and what type of weather you can expect from each.
Cumulus clouds are probably the most well-known of the cloud types. They generally form from convection, with air parcels rising vertically into the atmosphere (called updrafts) and condensing into the puffy, cotton-like clouds that we all know and love. Typically, cumulus clouds are associated with pleasant weather where you can lie back on the grass and admire the sky.
Above: Fair weather cumulus clouds over a field (Courtesy Wikipedia)
If updrafts become stronger, those seemingly innocuous cumulus clouds may grow taller into what we call cumulonimbus clouds. These are the awe-inspiring and ominous clouds mainly observed during the summer months and can be indicative of developing thunderstorms, including lightning, hail, heavy rain and even tornadoes. The strongest thunderstorms can even produce cumulonimbus clouds that tower up to 60,000 feet!
Above: Textbook example of a towering cumulonimbus cloud (Courtesy Wikipedia)
Personally, stratus clouds are my least-favorite and I'm sure that likely goes for most people. These clouds, which look like a layer of gray blanketing the sky, are generally associated with wet conditions. They typically form when warm air is lifted over cold air, which allows the water vapor to condense rather uniformly, transforming the sky into a gray and dreary scene. In fact, stratus clouds can last for days and bring cool temperatures, persistent rain, drizzle, or even snow.
Above: Layer of stratus clouds (Courtesy Wikipedia)
Now on to my favorite type of cloud, cirrus clouds! Ever notice those high, thin and wispy clouds that usually make for beautiful sunsets? Yep, those are cirrus. They develop very high up in the atmosphere and are actually made up of tiny ice crystals. We can see cirrus clouds in a variety of scenarios including outflow from large scale storms, like nor'easters, tropical cyclones and even thunderstorm complexes. They also form out ahead of warm fronts and can be indicative of upcoming precipitation. While cirrus clouds may filter sunshine and make for a beautiful day, don’t be fooled…they can signify impending storms!
Above: Cirrus clouds on a beautiful day (Courtesy geograph.org.uk)
Now we reach the clouds that are sometimes at the center of controversy, contrails. No, they are not formed as a result of chemicals emitted into the atmosphere, but mainly because of the water vapor released by the exhaust of an aircraft. When the aircraft releases the hot water vapor at such a high altitude, it becomes trapped in a very cold environment where it almost immediately condenses and forms a cloud. Depending on how dry the upper atmosphere is, the contrail cloud may stick around for mere seconds or spread out and become cirrus clouds for hours. However, these clouds are not associated with any weather.
Above: Contrails from the engines of a British Airways Boeing 747 (Courtesy Flickr.com)
The lenticular cloud is one of the more unusual cloud types and is more common to those living out west, especially in the Rocky Mountains. This cloud resembles a lens and is typically positioned over a high hill or mountain. As the wind blows against the mountains, it is forced upward and moisture condenses, forming a cloud that stays stationary until the uplift or moisture feed ends. Although these clouds could produce precipitation if dense enough, they are mainly an indicator of air turbulence downstream. However, due to their unique shape, many times they have been mistaken for UFO sightings!
Above: Lenticular cloud over Mount Hood in Oregon (Courtesy Wiki Commons)
Finally, we have mammatus clouds. These almost look like little pouches or bubbles of cloud hanging from the above cloud deck. Though their formation is still not completely known, they are generally associated with severe weather and usually extend from cumulonimbus clouds. Thus, you should always be alert for stronger thunderstorms if you ever see mammatus clouds! Such clouds also inform pilots of turbulent flying conditions and they are instructed to avoid the area.
Above: Mammatus Clouds in Regina, Saskatchewan, Canada (Courtesy Wikipedia)
Hopefully you can appreciate those beautiful, puffy masses of water in the sky whether you are an avid weather enthusiast or just curious when weather threatens. Not only can clouds make great photographs, but they can also provide insight into approaching weather, so keep an eye to the sky!
Also be sure to check out our YouTube Channel for weekly weather updates and our latest thinking on the Winter Forecast for the 2019-20 season. In fact, here's the second preview!
In terms of significant weather and overall temperatures, the Midwest behaved rather mildly in the month of August. Still, the region had its fair share of warm days, with a couple of standout weather events over the period.
Overall, northern Illinois finished right around normal for the month, only around a few tenths above normal courtesy of several warmer than average nights. Much of the Ohio Valley topped out warmer than normal as well, by as much as 1 – 2 degrees. A bulk of the above normal temperatures came in the first 3 weeks, with Chicago 1 – 2 degrees on the warm side for the initial 21 days, and 2 – 4 degrees over the average from Indianapolis to Columbus. This roughly translated to daily high temperatures from the 1st through the 21st between 83 and 89 degrees. The drop was significant however after this, falling below normal for the remaining days.
SUMMERTIME STORMS, AND A CHANGE IN AIRMASS
The warm weather during the first 2/3 of the month was about to undergo a gradual transition by the 4th week. A frontal boundary worked in from the northwest on the 18th into Iowa, eventually stalling over Northern Illinois on the 19th. This brought thunderstorms to Chicago which resulted in reports of wind damage not only the nearby suburbs, but quite close to the downtown Metro as well. This complex of storms also reached the I-70 corridor, pushing some of these impacts (even with a bit of hail) to Indianapolis.
This front was then on the move a day or two later as a transition in the weather pattern was getting set to take place between the 20th and 21st. Cooler air behind it provided the transition to at or slightly below average temperatures that held the rest of the month. It also provided some of the most notable weather of the month with several rounds of thunderstorms before its passage.
Radar image from KIND radar showing storms that passed through Indianapolis on 8/20/2019, with Base Reflectivitiy (left) and Base Velocity (right) side by side. The radar site is the approximate location of the KIND observation station (Indianapolis Internatoinal Airport), which recorded a thunderstorm wind gust clocked in at 73 mph!
Indianapolis received the worst thrashing from these storms. A bowing line of thunderstorms moved south and east quickly across Illinois into Indiana on the 20th. The storms passed through the city between 2 PM and 3 PM that afternoon. Gusts topped 70 mph or higher for a widespread area. The reporting station at Indianapolis International Airport clocked in with a peak gust of 73 mph, with gusts reaching the 60s and 70s frequently from 2:43 PM to 3 PM. The strength of these winds led to numerous reports of downed trees and structural damage. This same line was even able to survive the trip to reach southwest Ohio, with similar reports through Cincinnati a couple of hours later.
Despite the severe outbreak, to say that August was your average summer month would not be too far off. Temperature departures were rather mundane in a sense, though on the plus side by a degree or two. For the summer as a whole, precipitation followed in the same manner. After a wet and active June (highlighted by the soaker through the Ohio Valley), July and August received near normal precipitation overall. From Chicago, to Indianapolis and Columbus, most areas stayed within a range of 75% - 125% of average for the period.
Most in the Midwest started the summer with 100% of their normal rainfall, even going up to as much as 200% for June. Precipitation leveled off in the season's middle and remaining months.
Summer made its presence known in July 2019 with frequent hot stretches, significant rainfall, and severe weather events throughout the month. In fact, the number of days which featured above normal temperatures overwhelmingly exceeded the cooler days. As a result, it was a period that finished above normal in terms of both temperature and precipitation.
SEVERE AND SOGGY FIRST WEEK IN THE MID-ATLANTIC
July began where June left off in the Mid-Atlantic, with an active week of heavy rainfall and bouts of severe weather from Baltimore, MD to Trenton, NJ courtesy of several slow-moving fronts that made their way through the area. The first of these waves pushed through on the 2nd, in the form of a surface boundary which resulted in widespread reports of wind damage in Maryland and southeast Pennsylvania.
The most significant event followed a few days later, with the arrival of a more potent cold front and severe thunderstorms. In this instance, reports of downed trees and wires rolled in from Boston to Washington D.C. The storms were even enough to produce a tornado, which was actually captured by a surveillance camera in Mount Laurel, NJ. Though wind damage was not extensive, one unlucky car was flipped over by the brief spin-up.
The National Weather Service has CONFIRMED that an EF0 tornado touched down earlier this afternoon in Mount Laurel, Burlington County.
The tornado had wind around 70 mph.
A car was flipped over in a warehouse parking lot, as well as two air conditioners blown off a roof pic.twitter.com/v8s0dDAEy3
— PETER PLANAMENTE (@plana_journ) July 6, 2019
This same front proved to be tough to be rid of, as it slowed and became stationary over the Mid-Atlantic. Once again, this meant soaking rains from heavy thunderstorms on the morning of the 8th, with an eye on the immediate downtown of our Nation’s Capital. Given its urbanization and high population, this heavy thunderstorm activity brought significant impacts to the city in terms of flooding. To make matters worse, the event coincided with the morning rush hour, which left many motorists stranded. Washington’s Reagan National Airport collected 3.44” of rain, which was a record for the date, and the 4th highest 1-day July total in its history.
A few more severe weather events producing mainly wind damage dotted the rest of July. While a majority of the impacts were felt in the Mid-Atlantic, New England eventually joined in toward the latter half of the month. A tornado became one of the main stories (interestingly over Cape Cod), which tore the roof off of a hotel in West Yarmouth, MA. New England’s most significant and widespread severe weather episode wrapped up the month on the 31st, when potent thunderstorms brought down 70-75 mph gusts!
THE DOG DAYS OF SUMMER
Along with the active weather during the month, heat waves frequented the entire I-95 corridor through New England, as a more persistent ridging pattern finally took over. While heat and its impacts can vary from region to region depending on tolerance and other factors, a heat wave in the Northeast is met when high temperatures hit 90 degrees or higher for three consecutive days. Baltimore and D.C. naturally were impacted the most by this, averaging high temperatures of 91.7 and 90.9 respectively. While technically three separate heat waves occurred, the one in the middle of the month spanned 12 straight days in D.C. Baltimore managed 11 consecutive days around the same time, and even recorded back-to-back days where the mercury reached the century mark.
The heat was felt northbound as well. Overall temperatures finished 3 – 6 degrees above normal from Philly to Boston. Urban impacts also made for sweltering nighttime numbers as well, especially in Newark which recorded a +7.1 degree departure from normal with an average low temperature of 71.7 degrees.
HOT, RAINY… BUT NOT RECORD-SETTING
While July 2019 certainly was hot at times, historical numbers provide a reminder that it is… summer. The heat did not break records, but it did finish highly in the rankings. Baltimore’s aforementioned 91.7 degrees hit 5th in recorded history at Baltimore-Washington International Airport. Boston’s average of 86.6 degrees, though lowest of all the big cities due to its geography, was enough to get Logan Airport to the 3rd warmest on record.
Central Park, NYC
Not much has changed in the tropics since our last update in early July. At the moment, there are no named storms in the Atlantic, but the National Hurricane Center is watching a few disturbances that could show signs of development. We did have a “landfalling” hurricane here in the U.S. on July 13th as Barry moved ashore along the coast of Louisiana. It was a minimal hurricane as winds were briefly sustained at 75 mph. Flooding was the biggest issue for the Gulf Coast as the slow moving storm produced up to 20 inches of rain in Louisiana.
The tropics will get more active this month, which is to be expected as we progress towards the peak of the Atlantic hurricane season on September 10th. Chantal will be the next named storm followed by Dorian and Erin. So far, so good with our original WeatherWorks Atlantic Hurricane Forecast that was sent out in May. We are still expecting 10 – 13 named storms before the season ends on November 30th. Here is the link to the forecast and the original blog post that explains the overall pattern and expectations in the tropics: https://www.weatherworksinc.com/hurricane-outlook-2019
This July was what can be called a typical warm summer month in the Midwest, with plenty of heat and not as much rain as some previous spots for most areas. All locations were a few degrees warmer than average, with Dayton leading the way at 3.8 degrees above-average. Chicago also came in at more than 3 degrees over the norm, 3.1 degrees to be exact. Columbus and Indianapolis both were 2.8 degrees warmer than average for the month, with Cincinnati rounding out the list at +2.4 degrees. Rain varied, though many areas were drier than recent months. Dayton was the wet spot, seeing 5.71" of rain, which is 1.60" above average. Nearby Columbus and Cincinnati were much drier, with 3.22" and 2.41" of rain respectively, both more than an inch below normal. Indianapolis came in with 3.86" (-0.69"), while Chicago came in at 3.94" (+0.24").
As can be expected in a hotter than normal July, the region had plenty of stretches of 90-degree weather. Everyone saw multiple high temperatures in excess of 90 early in the month between the 1st and 5th, with many areas seeing another day or two above 90 around the 10th. The hottest stretch was the third week of the month, when everyone saw several days in which the high temperature topped 90, which combined with tropical humidity levels and very warm overnight lows to result in a sultry week. All cities got into double digits for the number of 90-degree days in July, and all saw more such days than normal.
While no daily record highs were broken, some of the overnight lows were warm enough to break records on July 19th; Indianapolis only dipped to 79 degrees, tying the record for the day. Chicago failed to even bottom out at 80 degrees, with a low of 81, breaking the old record for the date of 78 degrees. This is the warmest low temperature in Chicago since July 23, 2012 when the low was also 81°F.
A disturbance combined with the heat and humidity to spark areas of thunderstorms on July 2nd
With all the heat and humidity came scattered thunderstorms at various points. Many thunderstorms produced heavy rain and localized flooding, though the hit-and-miss nature of the storms prevented more widespread flooding problems. As can be seen by most locations being near-normal for rainfall on the month, these thunderstorms weren’t much more frequent than normal, outside of perhaps the first week of July in Ohio. Some isolated severe weather occurred through the month, though there weren’t any significant outbreaks. The most widespread severe weather occurred on July 2nd, when fairly numerous thunderstorms produced damaging winds across parts of Illinois, Indiana, and Ohio. Thunderstorms were also fairly numerous on July 20th and 21st across the region as a cold front moved through and broke the heat, with some thunderstorms again producing damaging winds.
— Joey M. Marino (@WxJmar93) July 20, 2019