Use the contact forum on the right sidebar to send me a weather or climate question!

What are you looking for? Try a search.

Tuesday, July 16, 2019

East Coast Braces for Typical Summer Heat Wave

By Chris Martz | July 15, 2019



Well, it's that time of year again, which means that it's only a matter of time before a heat wave grips a part of the country. Unfortunately, the hour class has run out and one is knocking on the doorstep.

As you can see in the map below (Figure 1), a ridge of high pressure is building in over the Mid-Atlantic, Midwest, and Northeast this week and will strengthen as we progress into the weekend.

Figure 1. GFS model - weathermodels.com.
While the heat wave will get progressively worse throughout the course of the week as the heat dome strengthens its grip, the weekend looks to be a "bake fest" (Figures 2 and 3). Highs across the lower Plains and up and down the eastern seaboard will be closing in on the 100° mark Friday, Saturday, and Sunday. 

Figure 2. NWS forecast high temperatures, Saturday - weathermodels.com.
Figure 3. NWS forecast high temperatures, Sunday - weathermodels.com
While I don't think many places will tie or break daily or monthly, records are certainly not out of the question. Some models, like the GFS and European, have been astonishingly aggressive with forecast highs, but I think there's more to be desired. I believe the models are overdoing the heat, but we shall see where the chips fall in the forthcoming days.

Relief will be on the order for next week, as an upper level trough ushers in some cooler air for the east coast.

Sunday, July 14, 2019

Is Climate Change to Blame for Hurricane Barry?

By Chris Martz | July 15, 2019



As a future meteorologist, the weather is something I truly enjoy. If you ask any meteorologist that I have met, or if you ask anyone who personally knows me, they'd tell you the same thing. I always think of the weather as being the current prevailing and/or forecasted atmospheric conditions that may be good or bad depending upon my preference.

Here lately, it seems like politicians have either been confusing weather and climate, or they are just weaponizing the weather to carry out their political agendas, and unfortunately, I think the latter is more likely to be the case.

Every week, various weather events are being used as evidence of the "climate crisis." In fact, over the last two weeks alone, four specific weather events have been used as evidence of our impending doom and gloom; the European heat wave, the Guadalajara hailstorm, the flooding in D.C., and most recently, Hurricane Barry, which made landfall in Louisiana on Saturday, July 13 (Figure 1).
Figure 1. July 2019 climate crisis events.
I have already written articles explaining why the Mexico hailstorm and flooding in D.C. are not signs of the so called "ecological breakdown" (I avoided writing one for the European heat wave due to a lack of time, information, and confusion on whether or not the record was official at the time). This article is focused on Hurricane Barry, which made landfall this past Saturday in Louisiana as a weak Category 1 hurricane.
As usual, people who have their facts backwards are using Barry as the latest "poster child" for climate change. Because people these days believe everything they hear or see on social media without taking five minutes to fact-check, they are succumbed into this dangerous way of thinking, that's politically motivated. 

Because some mainstream journalists (not all of them, there are good journalists out there) and many politicians are bombarding the public with hysterical nonsense about the weather day in and day out, people have been having anxiety and panic attacks because of even the most ordinary weather events, thinking that they are signs of human-induced climate change, when in fact they are not.

Whenever one extreme event is over with, the "climate crisis" moves somewhere else as the narrative shifts. It's not stationary.

I've created two interactive graphs which are shown below. 

The first graph shows the number of landfalling hurricanes in Louisiana by year since 1851.

(Both graphs are interactive. You can hover your mouse over the blue columns to see the year and the number of landfalling hurricanes corresponding to the year.)


As you can see by the graph above, there has been literally no trend in the number of hurricanes making landfall in Louisiana since record keeping began for the Atlantic basin (which includes the Gulf of Mexico and the Caribbean) in 1851. The most hurricanes to make landfall in Louisiana within a single season were three strikes, set in both 1860 and 1985.

The next interactive graph (below) shows the number of Louisiana hurricanes by decade since the 1850s.



As you can see by the red trendline in the graph above, there has been an insignificant decease in the number of landfalling hurricanes per decade in Louisiana.

(You can access the data yourself on the National Hurricane Center data archive.) 

Dozens of news articles such as this one and this one have surfaced, not to mention politicians, claiming that hurricanes, Barry included - and last year, Florence  are going to occur more frequently and cause more flooding in the future as the planet warms. Some articles were written prior to the storm being named by the National Hurricane Center, and others were written pre-maturely, i.e. before landfall.

Their scientific explanation roots itself in the very fact that a warmer atmosphere can hold more moisture, in addition to the fact that the amount of available moisture in the air increases as sea surface temperatures rise. Furthermore, climate activists make the case that hurricanes are starting to move more slowly as a result of a lessened temperature gradient between the poles and tropics (polar amplification) which slow the winds that move tropical cyclones, and as a result, dump out more rain on any given area impacted by a landfall.¹
The problem with attributing [at the very least Gulf of Mexico] hurricanes on climate change is that the sea surface temperatures in the Gulf have seen very little change since 1900. A little outdated I know, but recent sea surface temperatures in the Gulf are actually a little bit cooler than they were during the 1930s and 1940s (Figure 2).² 
Figure 2. Monthly Gulf of Mexico sea surface temperature anomalies from HADSST2 from 1900 to 2011. - Bob Tisdale.
But here's what they don't tell you. 

Tropical cyclones require many more ingredients to develop than warm sea surface temperatures - preferably at or over 80°F. The Gulf of Mexico's sea surface temperatures are plenty warm enough every year to produce hurricanes of any size and/or intensity. 

Most tropical cyclones can be traced back to tropical waves or cyclonic circulations that originally formed off of the coast of Africa - or elsewhere. Such disturbances are pre-existing conditions and may intensify into an organized circulation that is sustained by warm sea surface temperatures. 

If tropical storm systems, like hurricanes or tropical storms run into wind shear, the storm will fall apart as it becomes tilted vertically, which consequently draws in dry air, suppressing convection.³

Wind shear is generally higher in the Atlantic basin during El Niño events, when there's warmer than average sea surface temperatures in the Equatorial Pacific.³ During La Niña events, wind shear in the Atlantic, Caribbean, and Gulf tends to be lower. Both 2005 and 2017 were La Niña years (Figure 3), and were very hyperactive seasons in the Atlantic.⁴ 
Figure 3. La Nina years.
With El Niño fading currently (Figure 4),⁵ I'm actually a bit concerned that we might see an uptick in tropical development in the Atlantic, Caribbean, and Gulf of Mexico in the coming weeks and months.
Figure 4. CDAS Nino 3.4 time series.
A result of the Pacific Decadal Oscillation (PDO) undergoing a phase change into its warm mode in the late 1970s, is more El Niño events.⁶ Because of this, higher wind shear in the Atlantic basin likely contributed to the record "11-year hurricane drought" in the United States lasting from 2006 through 2016 (in between the active seasons of 2005 and 2017), when there were no major hurricane strikes (Category 3+) in the Continental United States.

It's a fair argument to make - and I would generally agree that natural variations in Earth's climate, changes potentially caused by man like land use, or some combination of the two could alter the intensity and/or frequency of weather patterns and extreme events like heat waves, tornadoes, wildfires, and tropical cyclones. However, the notion that a warming climate  caused by whatever reason - worsens such events is not supported by observational data. 

In fact, numerous studies and scientific reports have tried finding a linkage between recent human-induced climate change and tropical cyclones, and results have been inconclusive on the matter. 

For instance, the IPCC openly admitted in their 2013 report that tropical cyclones can not be blamed on climate change. In IPCC AR5 (2013), they stated:
"Globally, there is low confidence in attribution of changes in tropical cyclone activity to human influence. This is due to insufficient observational evidence, lack of physical understanding of the links between anthropogenic drivers of climate and tropical cyclone activity, and the low level of agreement between studies as to the relative importance of internal variability, and anthropogenic and natural forcings."
The National Academy of Sciences (NAS) also says that there is low confidence in attributing tropical cyclones on anthropogenic climate change (Figure 5).⁷
Figure 5. Climate change and extreme weather. - National Academy of Sciences (NAS).
So, why are people blaming hurricanes on man-made climate change? It's because they have no clue what they're talking about and are not interested in facts. It's that simple.

To blame or link extreme, life-threatening weather events, like hurricanes on man-made climate change while the storm is ongoing, is USELESS information to those who may be in the storm's path. The last thing they, or forecasters like me are worried about is whether or not increases in a trace, odorless gas in the atmosphere slightly worsened a storm headed their way. 

It's one thing for someone to link a single extreme weather event to climate change after the event is all said and done with, assessments are made, and statistics are looked over. It's another to write articles pre-maturely and assume things based on scientific illiteracy.


REFERENCES

[1] Skilling, Tom. "Why do some hurricanes move slowly?" WGN-TV | Chicago's Very Own source for breaking news, weather sports and entertainment. July 8, 2017. Accessed July 14, 2019. https://wgntv.com/2018/07/08/why-do-some-hurricanes-move-slowly/.

[2] Tisdale, Bob. "Are Gulf of Mexico Sea Surface Temperature Anomalies Near to Record Levels?" Bob Tisdale - Climate Observations. April 30, 2011. Accessed July 14, 2019. https://bobtisdale.wordpress.com/2011/04/30/are-gulf-of-mexico-sea-surface-temperature-anomalies-near-to-record-levels/.

[3] Sosnowski, Alex. What is wind shear and how does it impact hurricanes, other tropical cyclones?" AccuWeather. Accessed July 14, 2019. https://www.accuweather.com/en/weather-news/what-is-wind-shear-and-how-does-it-impact-hurricanes-other-tropical-cyclones/70007871.

[4] Null, Jan. "El Niño and La Niña Years and Intensities." Golden Gate Weather Service Accessed July 14, 2019. https://ggweather.com/enso/oni.htm.

[5] Cowan, Levi. "CDAS Niño 3.4 Index." Tropical Tidbits. Accessed July 14, 2019. https://tropicaltidbits.com/analysis/ocean/nino34.png.

[6] D'Aleo, Joseph. "Ocean Multi-Decadal Changes and Temperatures." Accessed July 14, 2019. http://icecap.us/docs/change/OceanMultidecadalCyclesTemps.pdf.

[7] "Climate Change and Extreme Weather." Penn State Department of Meteorology and Atmospheric Science. Accessed July 14, 2019. https://www.e-education.psu.edu/meteo3/l10_p9.html.

Monday, July 8, 2019

Something's Rotten in D.C., and It Isn't Those Rain Totals

By Chris Martz | July 9, 2019



It seems as if every day, there's someone linking ordinary and not-so-ordinary weather events to the "climate crisis." Dare I say that we should actually do a little fact-checking first. 


"Nope, we know the answer already. Climate change causes all weather events, big and small, normal and rare."

Yet, while my italicized quote is supposed to be funny, that kind of mentality has embedded itself into our reality. 

On Monday, July 8, Democratic congresswoman Alexandria Ocasio-Cortez (AOC) stated that "Unprecedented flooding is quickly becoming a new normal. Despite that, Republicans are tripling down on fossil fuels w/no plan to transition off them, or make the critical infra investments we need to prep for the climate crisis. Each day of inaction puts more of us in danger."
The irony of her statement - when was the last time a politician actually cared about the people they represent? Okay, okay, I'm going to stick to the science!

The congresswoman also stated that extreme weather or weather-related events like flooding and wildfires have gotten worse due to the "climate crisis." (I'm using "climate crisis" in order to be more scientifically precise, like The Guardian stated they would do with their articles. That was pure sarcasm).
Her reference to "unprecedented flooding" was fueled off of headlines detailing flooding in the Washington, D.C. area (where I live and forecast the weather). Indeed, she was right in the sense that the flooding on Monday was impressive, but the usual scaremongering tactic of blaming fossil fuel emissions on the event is just plain pseudoscience and superstition, and doesn't root itself in reality.

According to the National Weather Service office in Sterling, Virginia, official observations from Reagan National Airport indicate that 3.44 inches of rain fell Monday, July 8. This rainfall was not only a record for the date (old record was 2.16 inches from 1958), it was a little over 92% of D.C.'s average July monthly total rainfall of 3.73 inches!
All of this was caused by a complex of slow-moving thunderstorms that rolled through the area Sunday evening and Monday morning (I can confirm since I live in the area). This was not caused by magic CO₂ fairy dust in the atmosphere. 

Flash floods from thunderstorms generally occur when thunderstorm cells are slow-moving, or when different thunderstorm cells move over the same area over and over again.¹ The severity of a flash flood - in terms of how fast it develops and how high the water levels get  depend upon factors like the duration of the rain, the rainfall intensity and terminal velocity of raindrops, and/or soil moisture.¹ Sunday evening and Monday morning, the storms were slow-moving and rainfall intensity was high. In addition, last year (2018) was the wettest year on record in Washington, D.C. with 66.28 inches of precipitation falling on the city.² 2019 has also been a pretty wet year, with 27.12 inches of rain falling so far.² Thus, soil moisture remains high, and as a result, excess water from rain or runoff can't seep into the ground, creating a higher risk for flash floods.


Figure 1. Total precipitation January - December in Washington, D.C. 1872 - 2018,
So, with that said, does her claim about "unprecedented flooding" in D.C. hold any water? Spoiler alert, it doesn't!

Before I show the statistics, her statement doesn't even make any sense. If each new flood is "unprecedented," then that's climatologically not "normal." So how can it become normal? Maybe she means that flash/inland/river flooding is the new normal? If so, that's still wrong. Two strikes in a row AOC, the third is OUT.

Washington, D.C. has a long history of flash flood events, river flooding, and heavy rainfall events, most of which are not even noteworthy because they happen so often, especially the during spring and summer as daytime heating and high dew points act as "trigger mechanisms" to initiate thunderstorm development in the afternoon hours.




Heavy Rainfall Events

Meteorologist Kevin Williams of Rochester, New York made note that of the top ten heaviest 24-hour rainfalls in D.C., only two of the ten have occurred this century. Of the eight heaviest 24-hour rainfalls to be officially recorded in D.C. during the 20th century, seven of them occurred prior to 1975, and five occurred prior to 1970. 
So, obviously, heavy rainfall events in D.C. are not a new thing. What about actual floods?



Some Select Flash Floods & River Flooding in D.C. 

David Birch, a friend of mine and a well-known solar researcher in the climate community sent me this link Monday afternoon, which has a list and description of some of Washington, D.C.'s largest flood events in memory.

So, let's break it down.

1. The "Great Fresh Flood" of May 1771 was devastating to the Virginia colony and Washington, D.C. area.³  The Virginia Gazette reported, "...From the mountains, to the Falls, the low Grounds have been swept of almost every Thing valuable; and the Soil is so much injured that it is thought not to be of Half its former Value, and a great Part is entirely ruined...³

2. On June 2, 1889 the Potomac River crested 12.5 feet above flood stage. Many streets, including Pennsylvania Avenue were flooded (Figure 2).


Figure 2. Pennsylvania Avenue flooded on June 2, 1889 in Washington, D.C. Photo credit: Library of Congress.
3. The Flood of March 17-19, 1936 was one of Northern Virginia's, Maryland's, and D.C.'s worst natural disasters in history.⁵ This flood is often noted as the "Record Flood of 1936," "Great Potomac Flood," or the "St. Patrick's Day Flood of 1936."

March of 1936 was pretty warm in Washington, D.C., averaging 3.5°F above normal for the month, despite frequent drastic temperature swings from the 40s to the 70s and back.²

Most of Eastern West Virginia, Northern Virginia, and Maryland had received their entire March monthly average rainfall by mid-month. While most of the rainfall events were relatively small, the high frequency of them that March allowed stream water levels to increase. 

The storm that caused the major flooding was on St. Patrick's day in 1936, when a deepening low in the Carolinas pushed southeast winds and moisture into the region causing intense rainfall.⁵ While most areas in and around the D.C. area saw less than two inches of rain, areas to the west, like the Blue Ridge Mountains received well over four inches of rain in that two day period.⁵ The list below is from the National Weather Service. You can see just how impressive those two-day totals were (Figure 4).


Figure 3. Two-day rainfall totals from the March 1936 storm.
4. The "Record Flood of 1942" unfolded over an eight-day period; October 11-18. During this event, D.C. picked up over six inches of rain, and floodwaters reached the steps of the Jefferson Memorial (Figure 4).

Figure 4. Jefferson Memorial steps flooded in October 1942 flood.
5. The Flash Flood of August 11, 2001 was one for the books (Figure 5). What's odd about this flash flood event was that it occurred in a narrow band stretching from Warrenton, Virginia to Washington, D.C. Some storm reports from D.C. and nearby communities noted that upwards of seven inches of rain fell that day.⁴ Reagan National Airport only received 0.92 inch of rain during the event.²


Figure 5. Flash flood of August 11, 2001.



Weather vs. Climate

People like Representative Cortez seem to have a very difficult time grasping the fundamental differences between weather and climate, which is the fact that weather is based on short-term atmospheric conditions and climate is based long-term trends. 

Any individual weather event - regardless of how extreme it is and whether or not it's unprecedented  can simply not be used as evidence for OR against changes in Earth's climate system. The atmosphere - as we know - is very chaotic in nature and any type of extreme weather event is bound to happen at some time or another notwithstanding global average temperature change. 

If you look at the trends in global lower tropospheric temperature since 1979, you'll see that they have undoubtedly gone up, yet we've always had floods (hear that AOC?), we've always had hurricanes, we've always had tornadoes, wildfires, dust-devils, droughts, heat waves, cold waves, thunderstorms, blizzards, and monsoon seasons. While the frequency and/or intensity in such events may or may not alter in either direction due to changes in the climate, because they have always happened, because they're prone to happen, and because there's a lack of sufficient global long-term data, it is extremely difficult and arrogant to pinpoint one weather event as evidence of a "climate crisis."

Flash flood events like the one that occurred on Monday in D.C. are associated with thunderstorms, which are considered "severe convective storms." According to the National Academy of Sciences (NAS), there is very little evidence to link thunderstorms to man-made climate change, global warming, the climate crisis, or ecological breakdown - whichever way you'd like to call it.

Figure 6. Climate change and extreme weather - National Academy of Sciences (NAS).
If I were to sum up this nonsense in one sentence I'd say, "There's something rotten in D.C., and it isn't those rainfall totals, it's clueless politicians."


REFERENCES

[1] "Thunderstorm Hazards - Flash Floods" National Weather Service. Accessed July 9, 2019. https://www.weather.gov/jetstream/flood.

[2] xmACIS2. Accessed July 9, 2019. https://xmacis.rcc-acis.org/.


[3] Yeck, Joanne. "The Great Fresh of 1771." Slate River Ramblings... March 13, 2017. Accessed July 9, 2019. https://slateriverramblings.com/2017/03/13/the-great-fresh-of-1771/.

[4] Ambrose, Kevin. "Floods - Washington Area Floods." WeatherBook.com. Accessed July 9, 2019. https://www.weatherbook.com/flood.html.

[5] "1936 Flood Retrospective." National Weather Service. Accessed July 9, 2019. https://www.weather.gov/lwx/1936Flood.

[6] "Climate Change and Extreme Weather." Penn State Department of Meteorology and Atmospheric Science. Accessed July 9, 2019. https://www.e-education.psu.edu/meteo3/l10_p9.html.

US Gulf Coast put on alert for potential tropical storm to form late week

After more than a month of inactivity in the tropical Atlantic basin, development is likely in the northern Gulf of Mexico with potential impacts to residents and visitors later this week and this weekend.
A non-tropical system tracking through and triggering showers and thunderstorms across the South early this week will eventually end up over the warm waters of the Gulf of Mexico around midweek.
"The storm will then sit over the Gulf of Mexico for a few days and may eventually become partially or fully tropical in nature during the time period from late this week into next weekend," according to AccuWeather Senior Meteorologist Adam Douty.
Dry air, dust and strong wind shear has prevented tropical development across the Atlantic basin since Subtropical Storm Andrea briefly roamed the waters of the west-central Atlantic in late May.

Tropical Development 8 am

However, more conducive conditions exist over the eastern Gulf of Mexico.
With strong wind shear absent, warmer-than-normal waters of the eastern Gulf of Mexico can allow an organized tropical or subtropical system to take shape.
The next tropical storm in the Atlantic basin would be called Barry.
A subtropical storm has both tropical and non-tropical characteristics, but can have must as much impact in terms of heavy rain, rough seas and strong winds.
"One of the keys to whether a depression or storm will form is how close the system tracks to the coast," Douty added. "The longer the system remains over water, the stronger it may become," he said. "However, it may stay non-tropical if it stays near land."
Development of the feature will be slow initially. However, once it catches, and if the feature remains offshore, it could gain strength at a fast pace.
"Since there is a chance for the feature to move over open water, it is premature to say that the only threat will be from torrential rain," according to AccuWeather Senior Meteorologist Alex Sosnowski.
The latest trends in steering winds suggest more of drift toward the central and western Gulf of Mexico this weekend.
"There are a number of petroleum rigs and refineries along the central and western Gulf coast, and there may be considerable risk if this storm ramps up, develops to its full potential and travels in that direction," Sosnowski said.
Seas would turn dangerously rough for boaters and swimmers as the storm strengthens.
Regardless of development, the system may lead to multiple days of showers and thunderstorms that can spoil vacation and outdoor plans across the Southeast this week.
This week
Flood dangers can arise in areas that get hit repeatedly by downpours or where a more concentrated band of heavy rain unfolds.
"As we have seen in the past couple of decades in the Deep South, sometimes these tropical features stall and produce torrential rainfall once they make landfall," according to AccuWeather Hurricane Expert Dan Kottlowski.
"Allison did that in 2001 and Harvey did that in 2017," Kottlowski said.
While Harvey was once a major hurricane, Allison peaked as a tropical storm. So a powerful hurricane is not necessary for tremendous rainfall and flooding.
A broad area of moisture alone will cause downpours and localized flooding over parts of the Southeast, including the Florida Peninsula this week even in absence of any tropical depression or storm.
Downpours Gulf Wed Thurs
"Residents from western Florida to eastern Louisiana should especially remain alert for an increase in downpours and a heightened risk for flooding later this week and into the start of the weekend," Douty said.
The downpours would spread westward, depending on the storm's eventual development and track. 
Gulf Friday Saturday
After the system leaves the Gulf of Mexico, its eventual track will determine whether heavy rain aims for the interior South or the threat continues in the Deep South.
With weak steering winds now and into next week, any feature that wanders onshore may not be in a hurry to leave or move well inland.
Kottlowski has been warning since early April that the Gulf of Mexico, as well as areas east of Bermuda and off the southeastern coast of the U.S. need to be watched closely for early season development due to water temperatures running above normal.
AccuWeather’s 2019 predictions have not changed since the initial forecast was released on April 3.
Forecasters continue to call for 12 to 14 tropical cyclones this season. Of those, five to seven are predicted to become hurricanes and two to four are predicted to become major hurricanes.
While El Niño conditions may suppress the numbers of tropical storms and hurricanes in the Atlantic basin somewhat this year, all it takes is for one or two hurricanes to strike populated areas and result in great risk to lives and property.
This year, AccuWeather will implement its RealImpact™ Scale for Hurricanes to assist with public safety and understanding, as well as risk of damage should a tropical threat arise.
"If the scale was retroactively used, Tropical Storm Allison would have a RealImpact of 4 and Harvey would have a RealImpact of 5, based primarily on flooding rainfall," Kottlowski said.
Tropical Storm Emily from 2017 was the last time that a named tropical system made landfall in the United States during the month of July. Emily formed in the eastern Gulf of Mexico and moved into the central Florida Peninsula on the last day of July.
Tropical development more likely in the Gulf of Mexico
NHC Atlantic Activity
There are currently no organized tropical systems across the Atlantic Ocean, though AccuWeather meteorologists are monitoring for development across the Gulf of Mexico during the second half of the week.
A weak upper-level disturbance will drop to the south into the northeastern Gulf of Mexico later on Tuesday and into Wednesday and will slowly drift to the west through the remainder of the week. The water across the Gulf is very warm and wind shear is expected to be conducive for tropical cyclone formation. As a result, it is increasingly likely that a tropical system will form in the northern Gulf later this week.
Accuweather meteorologists will be closely monitoring this potential over the next several days. Given uncertainty in the track, anyone with interests from eastern Texas to northern Florida should monitor the progress of this system.
Elsewhere across the basin, either high wind shear or large amounts of dry, dusty air will continue to inhibit tropical development from the Caribbean into the eastern Atlantic.
By AccuWeather Senior Meteorologist Adam Douty.