Saturday, July 21, 2012

Space Weather

Hi it's just me again, I talk about the weather on this page and you hear about the weather all the time. weather is all around us and it's a very important part of how we plan our activities, go about our lives, and even how we dress. When talking about weather, usually we think of temperature, rain or snow, the speed and direction of the wind, air pressure, how humid it is. Basically when we say the word weather, we're talking about the day to day atmospheric conditions of a particular place. The earth is not the only place that has weather; most of the other planets in the solar system have it. There's weather of a sort even in deep space. This blog post will touch on what space weather is, the different types of space weather, and how it affects us on the planet Earth.

What is space weather anyway?

Just like earthbound weather space weather is conditions in space that change from time to time. In our Solar System all space weather starts at the Sun. The Sun gives off radiation. The amount of radiation coming off the Sun is not constant, sometimes there a lot and sometimes there's very little. However, there is always some, this flow of particles off the Sun is called the solar wind. Space is filled with magnetic fields in the solar system, The interplanetary magnetic field (IMF) is a part of the Sun's magnetic field that is carried into interplanetary space by the solar wind. Because of the Sun's rotation, the IMF, like the solar wind, travels outward in a spiral pattern that is often compared to the pattern of water sprayed from a rotating lawn sprinkler. Earth's magnetic field (also known as the geomagnetic field) is the magnetic field (MF) that extends from the Earth's inner core to where it meets the solar wind. Earths strong MF is the reason Earth has liquid water.

Magnetic fields and magnetospheres are beyond the scope of this blog post. However, I will give a brief explanation as to what they are, so that we all have the same frame of reference.

Most of the planets in the solar system have a MF. Venus has none and Mars has one that is almost nonexistent. The earth has a strong MF, because it has a core made of solid nickel and iron. This inner core is surrounded by liquid iron and nickel. Because the core is so dense, the magnetic field is very strong. The Earth's MF is formed the same way as an electromagnet. In an electromagnet you wrap some insulated copper wire around a piece of iron (for example an iron nail); the wire is attached to the positive terminal of an battery and the other end of the wire to the negative terminal. Electricity in almost all conductors is just the flow of electrons. When the electric current passes through the wire wound around the nail, it creates a MF. In the case of the earth as electrons flow around the core a MF is created. The Earth's fast rotation causes the electrons to move at very high speeds. As for Venus, in part, it has no magnetic field because Venus has a rotation speed that is extremely slow (243 days). The lack of fast rotation doesn't allow electrons to flow in the numbers that's needed to create an MF.

The Magnetosphere:

The region above the ionosphere is called the magnetosphere. Our magnetosphere is formed when a stream of charged particles, such as the solar wind, interacts with and is deflected by the magnetic field surrounding Earth. This magnetosphere is what protects the Earth from cosmic rays that would strip away the upper atmosphere, including the ozone layer that protects the earth from harmful ultraviolet radiation.

With the recent X-class solar flare and Northern Lights displays, you may have heard to something called Van Allen Belts. The Earth's Van Allen Belts consists of highly energetic ionized particles trapped in the Earth's MF. On the sunward side of the Earth, the MF is compressed by the solar wind, while on the opposite side of the Earth, the MF extend out much farther. As a result, inside the MF is an area known as the Chapman-Ferraro Cavity, which surrounds the Earth. The Van Allen Radiation Belts sit inside this area. It consists of an inner belt and a outer belt. The radiation belts contain protons, ions, and electrons. When particles from a Solar Flare interact with the belt some of the electrons produce auroras (the northern lights).

                                                     Solar particles interacting with Earth's magnetic field

                           Artist rendering of what solar influence looks like interacting with the magnetic field 

Sunspot Cycle:

The Solar Cycle (Solar Magnetic Activity Cycle). This cycle is what is commonly known as the Sunspot Cycle; it has a period of about 11 years in which the Sun goes from minimal sunspot activity...thru increased sunspot activity...and back to minimal sunspot activity. When the sunspot activity is high it's called the Solar Maximum, while the period of fewer sunspots is called the Solar Minimum. It reverses itself in both hemispheres from one sunspot cycle to the next. Therefore a full cycle takes around 22 years. The Suns magnetic field varies greatly during the cycle, During the solar maximum, the magnetic field is strong, so the Suns surface temperature is higher. On the other hand, during solar minimum, the field is weak, so the surface temperature is lower. Our current solar cycle 24 is forecast to peak in early or mid 2013 with 60 sunspots.

Types of Space Weather:

There are three major types of space weather events that impact technologies we take for granted here on Earth.

1) The first is a radio blackout, which is a disturbance of the ionosphere caused by X-ray emissions of a solar flare. Radio blackouts caused by space weather are measured by the National Oceanic and Atmospheric Administration on a scale that goes from 1 (minor) to 5 (extreme). In this event, the density of the lower region, known as the D-region, is increased, causing radio waves to be misdirected or absorbed. Conditions in the D region of the ionosphere have a dramatic effect on high frequency (3 - 30 MHz) communications and low frequency navigation systems. Examples of low frequency navigation systems would be VOR (VHF Omni-directional Range), Radar, and transponders. The intensity of the X rays determines how long the radio blackout last. It can last from as little as a few minutes up to several hours. Radio blackouts affect communications primarily at middle to low latitudes, but only on the dayside of Earth.

2) The second type of event is a solar radiation storm, which is also sometimes called a solar energetic particle (SEP) event . These happen when an explosion on the sun accelerates solar protons toward where energetic particles from the Sun, primarily protons, elevate the levels of radiation near Earth. Radiation storms cause harmful levels of radiation above the shielding provided by our atmosphere. Solar radiation storms are rated on a scale from S1 (minor) to S5 (extreme), determined by how many very energetic, fast solar particles move through a given space in the atmosphere. At their most extreme, solar radiation storms can cause complete high frequency radio blackouts, severe damage to electronics, effect memory and imaging systems on satellites. These storms potentially have an effect on astronauts and, to a lesser degree, passengers in commercial jets. A solar radiation storm can arrive in as little as 10 minutes and may continue bombarding Earth for a few hours to as long as several days.

3) The third type of event, a geomagnetic storm, is caused by a gust in the solar wind, such as a Coronal Mass Ejection (CME), energizing Earth's magnetic field. These disturbances reach Earth in as little as 18 hours to 4 days and may last for a day or two. Geomagnetic storms can play havoc with power grids damage satellites, but are also responsible for the magnificent auroras we enjoy watching. Geomagnetic storms are measured by ground-based instruments that observe how much the horizontal component of Earth's magnetic field varies. Based on this measurement, the storms are categorized from G1 (minor) to G5 (extreme). In the most extreme cases transformers in power grids may be damaged, spacecraft operation and satellite tracking can be hindered, high frequency radio propagation and global positioning system (GPS) can be blocked, and auroras may appear much further south than normal.

If you're into Ham Radio here is a good site.

A link to the NOAA space weather prediction center that shows the different levels of space weather and their effects can be found here.

Here's is a NASA video that talks about the Sun and the different types and causes of space weather.

Well that's it for this blog installment. The next post will cover the subject of bombogenesis. Rebecca

Tuesday, July 17, 2012

Why are higher elevations cooler?

Hi, it's Rebecca.  Last week I decided to let followers of my webpage and  readers of this blog suggest  a topic they wanted covered.  I'm going to pick three , one will cover why it gets cooler at higher altitudes. The second will go into a bit on solar and space weather. The third will cover bombogenisus .

Gary Sluzky, Asked:  "I live in the mountains, about 1,875' of elevation. I've always known it's cooler in the mountains during the summer, and colder in the winter, than Albany and NYC. Generally, we run about 7° - 8° cooler than Albany and 12° - 18° cooler than NYC. I realize that we are north of NYC by about 100 miles and that alone makes a difference, but we are also about 50 miles south of Albany, yet, we still run cooler. Obviously it's an elevation thing, my question is why?"

There are several reasons why this is occurring.

Longitude: As Gary implied, the farther  you get away from the equator the cooler the average temperatures get. This has to do with the angle of the solar radiation (radiant energy emitted by the sun)  moving through the atmosphere).  The sun is overhead at the equator, as you go farther and farther north the angle slants more and more.  This has a impact on the absorption and scattering of sunshine when passing through the atmosphere.  

Altitude: The reason, it get cooler the higher you go in elevation, has to do with air pressure. As you may remember from your high school earth science, At sea level, the pressure is around 14.7 pounds per square inch ; at 2000 feet the pressure is around 13.7 pounds per square inch,  and at 5000 feet the pressure is 12.2.  The change in pressure results in a change in temperature. At sea level the air molecules are close together (this means they collide with each other a lot), which puts them in a higher energy level. Whereas, at higher altitudes the pressure is lower, so the volume is higher ( the same number of molecules in a larger space) with all the extra room; they don't collide as often resulting in a lower energy level. So each square inch has a much lower temperature than sea level air.

Rural vs. Urban:

Rural areas on average are much cooler than urban areas. The difference between urban and rural temperatures is most prevalent when the winds are light, the dewpoint is moderate and the skies are clear. There is a lot more water in an rural environment. The trees and other vegetation release water vapor through pores on their surface.  This process is part of the water cycle it is called transpiration. Transpiration is a process similar to evaporation. As the water evaporates it cools the air.  Urban areas are mostly concrete and asphalt. Because of this rainfall runs off into storm drains. Whereas, rural areas are mostly grassland and forest, therefore the rainfall soaks into the soil. Also, in rural areas solar energy is absorbed into the environment much more efficiently than it is in urban areas. The solar energy helps evaporate even more water vapor. All of these things combine to keep the rural areas much cooler than their urban counterparts.   

Urban Heat Island Effect:

The urban environmental issues I just mentioned lead to something called urban hear island effect. All the concrete, roads and buildings absorb sunlight and trap heat. As a result, cities create their own, warmer microclimates. Cities are heat traps, because of the buildings and all the roads. most of the solar radiation is absorbed. The buildings are so close together that they reabsorb heat energy  giving off by their neighbors.   

Cities do have an impact on the local-scale weather. There is evidence that the urban environment aided in the development of a tornado that move through Atlanta in 2008. The study indicates a connection between the intensity of the 2008 urban Atlanta tornado and the heat island effect suggests that the hot, dry urban conditions may have led to a larger discrepancy with the surrounding atmospheric conditions, enhancing stability and thus intensifying the storm as it approached the city.

There are several reason why  cities have an impact on local weather. However, the two main ones are:  extra heat over the cities aids in the  formation of thermal updrafts, and the increase of atmospheric particulates caused by pollution.   which leads to more clouds than would have occurred if the city had not been there.

Here are a couple of graphics that show the heat island effect.

I hope this answers your question Gary, If anyone has an question, feel free to ask. The next blog post will be on solar and space weather. The one after that will be on bombogenisus and what the heck the word means.


Monday, July 16, 2012

My Top 20 List Of Mind Blowing Atmospheric / Weather Phenomena

I thought I would make a top 20 list of what I think is the most strange, amazing, and unusual weather phenomena in nature. The pictures are not all mine, Images may not be copied or used without the permission of the person owning rights to the pictures.

Honorary mention, Virga

Virga is when ice crystals in clouds fall, but evaporate before hitting the ground. They appear as trails from clouds reaching for the surface, sometimes giving the cloud a jellyfish-like appearance.

Image credit Marialuisa Wittlin

20) Mammatus Clouds

These clouds often accompany severe thunderstorms, but do not produce severe weather; they may also accompany non-severe storms as well. Even though they look scary they're not. Their presence doesn't mean a tornado is ready to form. In fact, these clouds are usually seen after the worst of a thunderstorm has passed. Mammatus clouds are formed when an updraft carries precipitation enriched air to the top of a cloud, the upward momentum is lost and the air begins to spread out horizontally, becoming a part of the anvil cloud in the thunderstorm. Due to its high concentration of precipitation particles (ice crystals and water droplets), the saturated air is heavier than the surrounding air and sinks back toward the earth. The subsiding air eventually appears below the cloud base as rounded pouch-like structures.

19) Roll Clouds

A personal favorite of mine, roll cloud are often confused with shelf clouds. Shelf clouds are attached to the parent cloud, whereas the roll cloud is not. Roll clouds can be hundreds of kilometers long, and, just as the name suggests, they roll. This is because of cold air rushing out of a downdraft from a storm front, lifting warm air which cools and sometimes forms this type of cloud. If you want to get an idea of what this actually looks like in motion then the video above shows a brilliant demonstration of this, so watch and be in awe.

18) Green Flash

Happens very briefly just before sunset and just after sunrise. Green flashes are not always green; they can be yellow, blue, or even violet. However, green is the hue seen most often. It usually lasts only a few seconds at moderate latitudes. The main cause for a green flash is the refraction of the shorter wavelengths of light in the atmosphere (atmospheric dispersion). The other reason is that the retina red-sensitive photo pigment becomes oversaturated the bright red color of the Sun, which can lead to a change in color perception.

Image credit goes to Paul Getman

Image credit P Braun

17) Sun Pillars

Sun Pillars are vertical pillars of light above and sometimes below the sun. They occur when the light of the setting or rising Sun reflects off high, icy clouds at different layers. It is also possible to see moon pillars.

Image credit lucycat

16) Mirage

This is another thing cause by the refraction of light. Most of the time objects look to disappears when something enters the mirage.

15) Colored Moons

Colored Moons are caused by such things as : excess smoke from forest fires, volcanic eruptions, , dust (during the 1930's the dust bowl era saw colored moon very often), and eclipses can cause the moon to change color.

Image credit Rayyan Photography

14) Moonbows

A rainbow is caused by the Sun shining on moisture droplets, most commonly in a post-rain atmosphere. A moon bow is much rarer only seen when the moon is low and full to almost full. Moonbows are created the same way as rainbows; the moon light hits water droplets and refracts in its component spectrum of different colors.

13) Fogbows

Fogbows are also called: Seadogs, White Rainbows, and Cloudbows. They are formed the same way a normal rainbow does, by the diffraction of light through water droplets. However in the case of a fogbow the effect is caused by very tiny droplets. Because the light is passing through tiny fog droplets, which cause more diffraction.

Image credit Ken Ichi

12) Anticrepuscular Rays

Formed at sunrise or at sunset. These appear to emanate not from the sun, but from the point on the horizon directly opposite it. The effect is caused by sunlight being sent through some well placed clouds.

Image credit Nate Cassell

11) Lenticular Clouds

These unusual clouds are a lens-like shape, tend to form at high altitudes, normally aligned perpendicular to the wind direction. Lenticular clouds can be separated into altocumulus standing lenticularis (ACSL), stratocumulus standing lenticular (SCSL), and cirrocumulus standing lenticular (CCSL). Some people call them Unidentified Flying Object (UFO) clouds. They may not be UFO's, but they will make you take a second look. These clouds can be shaped like a stack of lenses, a single large lens , or even just a particularly long cloud. This type of cloud forms where stable moist air flows over a mountain or a range of mountains, a series of large-scale standing waves may form on the downwind side. Lenticular clouds sometimes form at the crests of these waves. Under certain conditions, long strings of lenticular clouds can form, creating a formation known as a wave cloud.

Image credit C. Moses

10) Fire Rainbow

The rainbows are caused by ice crystals in the thin, distant clouds being at just the correct angle to refract the sunlight into the colors of the prism.. Fire rainbows are rare sights in the mid-latitudes, because they can only occur when the sun is 58 degrees or higher above the horizon. For the United States in general that pretty much relegates any sightings to roughly around 6 weeks either side of the summer solstice
Image credit Schristia

9) Noctilucent Clouds

These are high atmosphere cloud formations thought to be composed of small ice-coated particles; their precise nature remains a mystery. They form at very high altitudes - around 82 km above sea level - and are, thus, a quite separate phenomenon from normal weather. They are only visible against a twilit sky background when the clouds occupy a sunlit portion of the Earth’s atmosphere that refract light at dusk when the Sun has already set, illuminating the sky with no seeming light source.
Image credit Nige B

8) Gravity Wave Clouds

The reason these clouds are described as waves is because they look like waves in general, but they look like waves especially in motion . The way these clouds are formed is by a trigger mechanism must cause the air to be displaced in the vertical. Examples of trigger mechanisms that produce gravity waves are mountains, frontal systems, and thunderstorm updrafts, which creates this momentum in the clouds.

7) Kelvin Helmholtz cloud formations

These clouds are also known as billow clouds, shear-gravity clouds, KHI clouds, or Kelvin-Helmholtz billows. The rolling eddies seen at the top of the cloud layers are usually evenly spaced and easily identifiable. When two different layers of air are moving at different speeds in the atmosphere, a wave structure will often form. The upper layers of air are moving at higher speeds, these shearing winds will often scoop the top of the cloud layer into these wave-like rolling structures. The clouds often form on windy days where there is a difference in densities of the air, such as in a temperature inversion. If you ever see them grab your camera quickly, they don’t retain this shape for very long, and they don’t occur very often either.
Image credit Matt Lanza6) Katabatic Winds

These are also called down-slope winds, gravity winds, in southern California they are called Santa Ana. They are formed when wind blows down a slope. These winds carry dense air from a higher elevation to a lower elevation because of gravity. It occurs at night, when the higher elevations radiate heat and are cooled, air in the higher elevation is also cooled, and it becomes denser than the air at the same elevation, it therefore begins to flow downhill. This process is most pronounced in calm air because winds mix the air and prevent cold pockets from forming.
Image credit vectorchem

5) St Elmo’s Fire

This weather phenomenon involves a gap in electrical charge. It's like lightning, but not quite. Lightening is the movement of electricity from a charged cloud to the ground, or another cloud. Whereas St. Elmo's Fire is more or less just a spark, It appears like fire on objects, such as the masts of ships, lightning rods, or church steeples. It occurs most often on pointed objects because the tapered surface will discharge at a lower voltage level. St. Elmo's Fire is exactly what's happening in neon tubes -- essentially a continuous spark. A neon tube is simply St. Elmo's Fire contained in glass. This occurrence was named the after St Elmo, the patron saint of sailors.
Image credit Pawel Forczek

4) Sprites, Jets, and Elves

All refer to phenomena that occur in the upper atmosphere in the regions around thunderstorms. They appear as cones, glows and discharges. They were only discovered last century, because of their placement and their very brief life-span (They normally last from one to five seconds).

A link at the University at Albany-SUNY that shows more info can be found here. 

3) Morning glory clouds

These rare cloud formations are low lying (at around 300-600 feet high) that can occur in various places around the world. It's a type of roll cloud that can be over 600 miles long, a little over a half mile to a little over one mile high, and move around 35 mph. These clouds are classed as types of roll clouds and whilst having a lot of the same characteristics, they can come in rows. The Morning Glory is often accompanied by sudden wind squalls, intense low-level wind shear, a rapid increase in the vertical displacement of air parcels, and a sharp pressure jump at the surface. In the front of the cloud, there is strong vertical motion that transports air up through the cloud and creates the rolling appearance, while the air in the middle and rear of the cloud becomes turbulent and sinks.
2) Ball Lightning

If you have ever seen a mysterious ball of lightning chasing a cow or flying through your window during a thunderstorm, take comfort from the fact that you have witnessed one of nature's rarest phenomenon. Ball lightning is a slow-moving ball of light that is occasionally seen at ground level during storms. A few fortunate people (my dad is one of them) have seen it float through walls. Ball lightning is thought to be a ball of plasma that is formed when a bolt of lightning hits the ground and creates a molten "hot spot".. It can come-in different sizes, but generally it manifests as a grapefruit-sized sphere of light moving slowly through the air. However, It has been reported to be as large as eight feet in diameter and can cause great damage. It only last for a very short time whereas it may end by fizzling out or exploding

Image credit goes to evilgeniuses4abettertomorrow's photostream.
Image credit Dalesman 2012

1) Non-aqueous Rain

Most of you have heard the saying "it's raining cats and dogs", But what would you do if it actually was? When it's raining animals it's called non-aqueous rain. It is extremely rare, but there are documented cases of it occurring. Stories of animals raining from the sky have been with us for thousands of years. Meteorologists are still unsure of the cause. However most including myself, tornado or waterspout, suck the creatures out of ponds and rivers and carry them to dry land. We know a tornado on land pickup many things, so it stands to reason that a tornado over the water could pick up water, and whatever is therein, into the clouds. It is suspected that strong winds can carry a load a long distance.

Another thing that is similar to non aqueous rain is colored rain. Red rain is caused by dust or sand that has blown into the atmosphere and is carried by the wind to great distances eventually mixed with rain clouds and gives color to the rain itself. Red rain in Europe is usually colored by the dust that is carried across the continent comes from Saharan sand storms. Other colored rain that can occur due to other objects such as : pollen could make a yellow rain, dust from coal mines could create a black rain, dust and even some rain could make white milk.

Well that's my list, There are other atmospheric and weather phenomena that I didn't cover. Like I said these were my favorite. I will post another blog on these other phenomena in the near future. I asked for input for the next few blog post, So far, I've had a few, the next post will cover why higher elevations are cooler and the urban heat island effect; it will also talk about Solar storms. with the recent X-Class flare heading our way I thought it would be a good time for it. I hope to have it up sometime between tomorrow and this coming Tuesday the 17th. Anyway, I hope you enjoyed this post and maybe learned a thing or two. As always questions are welcomed.


Wednesday, July 4, 2012

The Incredible Super Derecho Of June 29th 2012

Hi it's Rebecca again, After the destructive derecho last Friday; I thought I would do a write up about it. This post will explain what a derecho is as well as talk about the timeline of the super derecho on the 29th. 

What is a derecho? 

A derecho is a widespread and long-lived wind storm that is associated with a band of rapidly moving showers or thunderstorms that assume a curved or bowed shape. The bow-shaped storms are called bow echoes. Bow echoes typically arise when a storm's rain-cooled outflow winds are strong, and move preferentially in one direction.  Although tornadoes can be produced by a derecho most of the damage is from straight line winds. Normally if the wind damage swath extends more than 240 miles and includes wind gusts of at least 58 mph (93 km/h) or greater along most of its length, then the event is called a derecho. The most severe derechos are given the adjective “super.” Derechos fall under the heading of  Mesoscale Convective System ( MCS).  A MCS is a  complex of thunderstorms which becomes organized on a scale larger than storm scale and smaller than synoptic scale.

In meteorology there are four basic weather scales.
 The largest scale is synoptic-scale (also known as large scale or cyclonic scale) is a horizontal length scale of the order of about 600 miles or more. This is the  high and low pressure systems you hear mentioned on TV weather reports (e.g. extratropical cyclones).

Meso-scale meteorology is the study of weather systems smaller than synoptic scale systems but larger than  storm-scale systems. Horizontal dimensions generally range from around 5 miles  to few hundred  miles or so. Examples of meso-scale weather systems are sea breezes, squal lines, and mesoscale convective complexes.

Storm-scale is a scale of sizes of weather systems on the order of individual thunderstorms.

Miso-scale is the scale of meteorological phenomena that ranges in size from a few hundred feet  to about 3 miles. It includes rotation within a thunderstorm.

Well  I don't know about you but to me that's a lot of gobblygook.  Therefore I will give this definition:  A derecho is basically a large cold pool of air that gets dragged down from the upper atmosphere. When the cold air hits the warm moist air mass, storms explode and they self propagate.  They will keep going as long as the air mass being pushed into has enough warm moist air for it to feed on. Once on the move they produce incredible straight line wind damage over hundreds of miles.

The Set Up:
The set-up was classic for a derecho. We had extreme instability and extreme heat over the entire  region. Also there were other conditions present at are necessary for the development of a derecho.  The first is a strong jet streak overhead (See image 1).   Having a midlevel SE flow ( see fig 2). It is also an aid to development.  Third there was a boundary zone that was separating a dry and cool air mass to the north from the humid and hot air mass to the south.

                                                                              fig 1
fig 1 shows where the 250 mb jet streak was located.

                                                                                  fig 2

fig 2 shows the 500 mb level (18,000) feet.  the lines (isotachs) show supporting winds (the yellow arrows show the direction). when you see isotachs lined up like this it means there is a very strong high pressure system over the SE U.S. A  setup like this aids in the establishment of a derecho. On the 29th there was a moderate to strong vertical wind shear above ground in the lowest 2.5 km. The upper flow was also northwesterly. This type of setup allows small impulses to ride along the northwest flow at the edge of the upper-level heat dome to the south. . The winds at the 500 mb level also help stear weather systems like the super derecho.
All of these conditions were more than met across the  Midwest and Mid-Atlantic on the 29th  as there was extreme instability in place 6000 MLCAPE across Kentucky  and Ohio with 4500s into West Virginia. The heat dome over the region had been responsible for hundreds of record highs being broken during the days preceding the derecho. On the 29th the surface air and dewpoint temps were at record high for June; many place were in the mid 90's into low 100's. with dewpoint in the mid 60 to low 70's. there was a strong upper level jet streak just to the north of this region and extreme heat enveloped the entire region along with a boundary zone set up just to the north.
A blog post I did that covers a bit more on derechos can be found here.

A blog post that talks about the "Ring Of Fire" by my good friend Andy Gregorio can be found here.

The June 29th Super Derecho.
The derecho on the 29th began as a cluster of storms that developed in Eastern Iowa. As it marched east into Northern Illinois and Indiana. The cluster  erupted during Friday afternoon near Chicago, IL and then rapidly grew in intensity and coverage as they raced southeastward.  The MCS developed into a bow echo in Indiana as it continued to intensify. Over Ohio it matured into a derecho . The derecho  would continue expand and envelop  larger and larger areas as it headed into the Mid-Atlantic. The derecho reached the coast at around midnight.  The path of extreme damage was about 650 miles long in just 11 hours.  (see fig 3 and 4) Winds of 70 to 80 mph were common along the damage path,  with some seeing wind gusts that ranged between 90 to 100 mph. This event was very widespread.Of the over 1200 damage reports   Over 800 were wind damage reports that will cost  several million dollars (see fig 5). A thing that surprised me was that a derecho of this intensity only produced two confirmed tornadoes.  There were millions of people who lost power. Unfortunately the storm caused 23 fatalities. As power crews race to restore power to around a million people, this number could climb farther if people circum to the heat of the ongoing heat wave.

                                                                                     fig 3

                                                         Showing the progression of the derecho

fig 4
          Another view of the damage path

                                                                                         fig 5
SPC damage reports 

Timeline of June 29th 2012 super derecho:

  At 8:00 a.m. EDT

A few thunderstorms start to breakout in Eastern Iowa.
At 8:30 a.m. EDT.
The storms are intensifying as they cross into western Illinois.
At 8:51 a.m. EDT.
 The NWS starts to issue severe thunderstorm warnings for Northwestern Illinois.
At 11:35 a.m. EDT
The cluster of thunderstorms starts to form a bow echo west of Chicago.
11:50 a.m. EDT
The storms have cleared Illinois and are rapidly intensifying as they enter Northwest Indiana.  At about the same time, the National Weather Service in Sterling, Va.,  introduces enhanced wording that there is a increased chances for thunderstorms for the Washington DC area, feeling that the thunderstorms  most likely will keep rolling east.
12:14 p.m. EDT
 The Storm Prediction Center (SPC) begins tracking the evolution of the developing MCS in Illinois and Indiana. However, they fail to truly comprehend the  true nature and danger that is developing. At one point an operational forecaster states that the "extent of the severe threat should be limited to areas west of the Appalachian Mountains."
12:50 p.m. EDT.
The SPC  issues a severe thunderstorm watch for northeastern Illinois and the northern half of Indiana.
At 1:08 p.m. EDT
The MCS has grown in both size and intensity.
At 1:17 PM EDT
The first tornado warning of the day goes up in northwest Ohio.
1:54 p.m. EDT.
 Fort Wayne International Airport records a wind gust to 91 m.p.h. Emergency officials in parts of Indiana begin reporting "massive damage" following passage of storms.
2:15 a.m. EDT
The MCS has developed into a wicked bow echo as it continues to gain strength and momentum.
3:30 p.m. EDT.
The SPC  upgrades parts of Indiana, Ohio, and West Virginia to a moderate risk of severe weather and warns of "significant winds."
4:03 p.m EDT.
 The SPC classifies the "widespread/locally significant wind damage"   as a derecho.

Between 5:00 - 5:20 p.m. EDT.
  TV meteorologist go on air  taking about the possibility of severe thunderstorms in the Ohio Valley and Mid Atlantic states.

5:37 p.m. EDT.
 The NWS, introduces increased chances for thunderstorms - some severe weather  - for the region. They are becoming increasingly concerned about the ongoing derecho over the Ohio Valley.
6:30 p.m. EDT
The derecho has pushed across the Ohio River and has moved into West Virginia, falling trees have trapped numerous people in their homes.
7:20 pm EDT.
 Yeager Airport,  in Charleston, recorded a 77-mph wind gust.

7:50 p.m. EDT
The SPC realizes the derecho moving over  West Virginia and warns it will  continue to roll beyond the east slopes of the Appalachians and move into  Virginia.

8:00 p.m. EDT.
The SPC upgraded parts of Virginia, Maryland, and Washington D.C., to a moderate risk of severe weather and issues a severe thunderstorm watch with extremely high winds likely.

A little after 9:00 p.m. EDT. (this is an interesting side note) Amazon's Cloud Service fails, this in turn took down Netflix, Pinterest, Instagram, and other services across North Virginia.  

9:08 p.m. EDT
The National Weather Service enhances the severe thunderstorms warnings in Virginia using the  wording warning of "destructive winds."
10 p.m. EDT.
The derecho is  approaching the Washington, D.C. metro area. It is still  producing powerful damaging wind gusts. Between 10:00 pm and 11:00 pm EDT. Airports in Virginia and Maryland are reporting wind gust of between 70 and 80 mph .
10:10 p.m. EDT
 The NWS issues the warning for the people in Washington DC and the surrounding counties "This is a dangerous line of storms... These storms are capable of producing destructive winds in excess of 80 miles per hour. This is a serious situation. You need to take cover now."
 12:50 a.m. EDT
The last two people  lose their lives when powerful winds toppled a pine tree onto a tent.
 1 a.m. EDT 
The derecho was crossing over southern New Jersey, and the final reports of wind damage came in around 1:40 a.m. in Tuckerton, N.J., where winds were reported to have gusted to 81 mph.

A timelapse of  NEXRAD base reflectivity of the 29 June 2012 derecho.  The timelapse starts in  Davenport, Iowa and ends in  Richmond, Virginia. It can be found here.

Here we go again, lets all blame the NWS:

Another meteorologist friend of mine Matt Lanza brought an article out of the Baltmore Sun to my attention.
The article  talks about the derecho and how forecasters didn't anticipate the extent of how things would unfold on the 29th. Now that much is true. As I pointed out in this blog post. forecasters didn't expect the type of storm that developed last Friday. However the way the article is written it implies that power crews, government offices and the general public were caught off guard with no warnings at all, until after 10 p.m EDT. This is far from true. As I've shown in the timeline of the storm. The SPC, the NWS local field offices, and local weather TV meteorologist  were giving warnings well before that time. It always seems that when a rare event like this happens, the first thing just about everyone does is point a finger at the meteorologist and say...  I didn't know this was going to happen, because you never told me... This blame the weatherman for everything is starting to wear on me. Everyone needs to listen for warnings and respond to them. This hide your head in the sand mentality is also starting to wear on me. I've wrote several post where I berated individuals for  falling to heed warnings from the NWS, be it come outside to see what going on, drive to the store, or just flip the channel on the TV and sit there, during a tornado warning  The general public has to except their share of the responsibility for failing to act on any warnings given.  Now I agree the SPC and the NWS fumbled the ball on the June 29th super derecho; but, I'm sure the local NWS field offices issued warnings with enough lead time for people to take shelter. The SPC did underestimate the strength of the derecho. This event shows,  while we understand many things about  the science of  meteorology, there are still many things we don't completely understand. But we're getting better every day. Matt Lanza said "The whole warning system needs an overhaul in my opinion. You need tiered warnings for events. I don't know how this gets accomplished in a way that makes sense...I just know that this is what needs to be done. Unfortunately you can't always delineate between EF-0 and EF-3 TOR on radar...which makes this idea difficult to accomplish in reality. But something needs to get done somewhere". I completely agree with this statement. I've said in the past that the severe warning net can and should be improved. But people are the weak link in the chain. For people to sit there and blame the NWS for failing to issue warning everytime something like this happens is ridiculous.     

Here is one of the post I've writen abut this subject. It can be found here.

A link to the article can be found here.

                                                                                 fig 6

Fig 6 was taken by Aviation Dave as the super derecho rolled into the Cincinnati/Northern Kentucky International airport

                                                                                      fig 7

Fig 7 shows the derecho climatology for the United States. As you can see the Northeast normally see's a derecho once every four years.

Well that's it. I hope you enjoyed reading this post and maybe learned a thing or two. As always questions and remarks are always appreciated.