Thursday, May 29, 2014

Lightning Safety.

With the severe weather of late I thought I would make a post about lightning safety.

Here is a video I saw yesterday on someone's page. It shows a person taking a video of a thunderstorm......They are struck by lightning. in the video you can see pieces of pavement and dirt thrown into the air by the strike.

This is why I always say lightning is a greater danger around storms than tornadoes. In this case the chaser ended up OK...but the storm did damage the cars electronics.......
Because I chase Severe Weather, I've had close calls with lightning...I've had a few where all I heard was a crack or snap and then the blast of time sitting watching a storm, mine and everyone's hair stood on end...the bolt missed the car by five feet.......another time sitting on the door ( yes the window was down :) ) that time the lightning hit behind us somewhere, but it was close enough that I felt the tingle in my arms and legs.......So lightning and me do know each other.
They say you can't hear lightning, only the thunder it causes...and for the most part that is true. But I've been close to storms more than a few times.... sometimes I could hear a static like or a zipping sound, almost every time I heard that sound there was lightning running along the cloud overhead....these are called anvil crawlers...they are very beautiful but extremely dangerous....they can sometimes be hard to see in the daylight...but if you see them or hear the sounds I described, get back in your vehicle or go inside a building....anvil crawlers can become a cloud to ground strike.........

A few safety tips.
When a thunderstorm approaches, don't wait until it's overhead and starting to rain, before you seek shelter. As soon as you hear the sound of thunder, get inside a  vehicle (car or truck) with a hardtop roof, or go inside a building.
Don't take shelter under trees, trees attract lightning.
Avoid contact with electrical equipment, appliances, or power cords, if you do unplug your electronics during thunderstorms, do so well before the storm is overhead.
Most people have heard, don't wash your hands , don't take baths or showers, don't wash dishes, and stay off of corded phones during thunderstorms.  But, you also don't what to do laundry. Not only are washers and dryers in contact with wiring and plumbing, but the drier also has a direct path to the outside through the dryer vent.  
Stay away from windows and doors, and stay off porches. avoid gazebos, those small wooden, vinyl, or metal utility sheds....all of these offer little or no protection from lightning.
Don't lie on concrete floors or lean against concrete walls, they often contain metal reinforcing bars.

If you are caught outside in a storm, put your feet as close together as you can and crouch down with your head as low as possible. The only thing you what touching the ground is your feet.
I've done a few post on lightning safety.....

Here is one that deals with severe weather safety.... you can find it Here.
Here is one on how to photograph lightning can find it here.
I hope you enjoyed reading this....stay safe this Summer.........



Wednesday, May 28, 2014

The 2014 Atlantic Basin season...........

This is my first Tropical blog post of the 2014 season.


We've already have had Hurricane Amanda in the Eastern Pacific. A few days ago she rapidly intensified into a 155mph  storm. However, now Amanda is a tropical storm and is weakening rapidly.


The eastern Pacific tropical season started on May 11. During an El Nino, the eastern tropical Pacific normally sees an active season, Amanda has started the Pacific season with a bang.....forming just a little over a week after the season started....One more thing, Amanda is now the strongest May hurricane on record in the eastern Pacific basin during the satellite era.



What's going on in the tropical Atlantic Basin?

We have a few tropical waves over the Atlantic and Caribbean, but these are of no real consequence.  The upper level low in the southern Plains is causing showers and thunderstorms along the Gulf Coast, due to the southeast flow. The eastern GOM is under a ridge caused by the Azores high.  We also have a shortwave moving over the central Caribbean bring unsettled weather to Hispaniola. All of this is nothing to write home about.

The tropical Atlantic Basin has been quiet....but could this be ready to change?    

Some of the models are showing something developing in the Gulf Of Mexico (GOM).  We will see the remnants of Amanda  moving off the Yucatan, end of next week?  The question is what will it do as it moves out across the GOM.  Some of the models do show some organization. But others show this area of low pressure weakening. 

Shear over the GOM is looking to be unfavorable for much in the way of development. So I'm agreeing with the idea of not much happening with Amanda's remnants.
But nothing is set in I will keep an eye on the GOM.

What will 2014 look like in the Atlantic Basin?

ENSO-neutral conditions continue.  But sea surface temperatures (SST) are above-average across the equatorial Pacific Ocean. and the odds are we will see El Nino later in the year, most likely in the Fall.   

About eight weeks ago, I mentioned  My early thoughts on the tropical 2014 Atlantic Basin outlook. I said, based on the likelihood  of El Nino later this year..... It looked like there would be....

8 to 11 Atlantic Basin Tropical Cyclones,  with  5 to 6 of them becoming hurricanes,  I or 2 becoming major, with the likelihood of 1-2 tropical cyclones making landfall on the US.  But this would depend on if the El Nino was east based or central based......

I haven't changed my mind on the above numbers I posted in the Beginning of April..... As of now,  It is looking increasingly likely that this year's El Nino will start out as eastern based, then shift to the central Pacific, due to the fact that SST are well above normal in the eastern Pacific and near the Date Line.

Well the National Oceanic and Atmospheric Administration issued its seasonal hurricane forecast Thursday calling for eight to 13 named storms, of which three to six could become hurricanes, including one to two major hurricanes. ....This is in line with what I said back in April.

Back in April, Colorado State University seasonal forecasters Phil Klotzbach and Bill Gray called for below average activity with nine named storms, three hurricanes and one major hurricane.

Average tropical season in the Atlantic Basin is 12 named storms, 6 of these becoming hurricanes, with one to two becoming major.

The season will bear out who is right............

But do the numbers really matter?

While there is some skill at predicting a tropical season.... It is still basically reading tea leaves.  If you recall the tropical outlook from last year; you will remember just about everyone was calling for an active season, even the updated outlook NOAA put out in August, still called for an active season.  The tropical season of 2013 taught everyone that hurricane forecasting and reading tarot cards  have a lot in common.

If this is true, then why even issue an outlook? The idea of a tropical outlook is to give an idea of how active a season will be...... What it can't tell you is where they will strike..

The point I'm making is don't just pay attention to the numbers.  All it takes is one landfalling tropical system to have a major impact on people's lives.  We've seen what landfalling systems can do in the Northeast with Irene, Lee, and Sandy.

So no matter how many tropical cyclone develop in the Atlantic Basin this season don't let your guard down.... prepare and have an hurricane plan.

I do want to remind everyone that you can stay up to date on what's going in in the tropics, by using my Tropical Weather page on this site.     

Tuesday, May 27, 2014

The Northeast severe weather outbreak of May 22, 2014.

May 22nd, 2014 was a day severe weather was expected.  I had been posting about it for a few days, so everyone should've had adequate awareness . But the severity of the weather, exceeded the wildest dreams of the NWS, Myself, or any of the weather outlets that I know of. 

By the end of the afternoon heavy rain, damaging straight line winds, flash floods, large hail (large even by Midwest standards), and at least two tornadoes,  struck New York State, Pennsylvania, Maryland, Delaware, and southern New Jersey.

The severe storms caused millions of dollars in damage.

I did a blog post about severe weather outbreaks in the Northeast around Memorial Day.

What is it with Memorial Day and severe weather 

This post will go a little into the atmospheric setup for the 22nd outbreak. It will also touch on some to the hail storms and briefly on the two tornadoes.  It will also discuss the communication issues the National Weather Service (NWS) faced that day.

The setup leading to the severe weather. 

The Storm Prediction Center (SPC) had Southeast New York State, Eastern Pennsylvania , Maryland, Delaware and parts of New Jersey under a slight risk for severe...the main risk was for damaging winds and small hail.  Some of you have messaged me, saying it was a classic textbook setup for what transpired.  But I can assure you, this wasn't the case. We had a setup that was going to allow for scattered severe weather, with isolated damage expected.  The atmospheric setup was marginal  ( moderate at best).  

On Thursday we had an upper level low moving through Ontario, CA, with a trailing cold front stretching back into the Ohio Valley.  Embedded in this upper level feature was a shortwave trough.  Out ahead of the advancing cold front was a stationary front, That would soon start moving eastward.

Thunderstorms had moved through during the overnight and morning.  leaving debris clouds in their wake. But by late morning clearing had developed ahead of the advancing frontal boundary.



By mid day we had the  warm front advancing through Central NYS and moving into Eastern PA.  Out ahead of the warm front a south to southwest flow was allowing  warm and muggy air to move into the Northeast.

As we moved into the afternoon a relatively narrow warm sector was setting up across Eastern NYS, Eastern PA, and down into the Mid Atlantic.  The outbreak of sun, allowed very warm surface temperatures to develop heading into the afternoon, Temperatures were in the upper 70's and well into the 80's for New York State down into Virginia, dew  points in the 60's. At the same time, the 700mb temperatures were much colder. The instability due to the heated surface and rising dewpoints,  started to reverse the cap that was causing convective inhibition, as the cap started to breakdown cells started to develop and build.   At around the same time, mid level  flow was increasing But the low level shear was lack luster.  It was becoming evident that, the boundary between the warm air moving in and the cool air over New England was going to be the focus for some hefty cells.  Due to the lack of low level shear, the threat for tornadoes was thought to be very slight.  

 As we approached 2:00 PM the air became increasingly unstable. CAPE values of between  1500-2200 J/kg overlapped with relatively high surface-500hPa bulk shear values up to 45 to 50 knots. Ahead of the warm front, lifting was enhanced due to the fact that the region was under the left exit region of a jet streak. The setup as sufficient for the production of supercells.  

Mid-Level Lapse rates were in the range of... 6.5 C/KM to 7 C/KM... Also remember we had all that cold air aloft. So the possibility of hail was a no brainer. But the size of some of the hail would go well beyond what anyone had imagined earlier in the day.    

Once the warm surface temperatures and high dewpoints ran into the unstable air. The storms exploded.  The instability extended well over 60,000 feet up. The cells over parts of Eastern NYS, Eastern Pennsylvania, and down into Maryland, Delaware  developed into supercells,  capable of producing hail and strong wind gusts. Several of the cells grew to over 50,000 feet.  The violent updrafts  carried the rain and particulates aloft well above the freezing level, where they formed into hail. The updrafts and downdrafts kept the hailstones aloft, allowing them to grow increasingly larger. But they became too heavy for the updrafts to support. As gravity took over, the hailstones became destructive missiles as they crashed into objects on the surface.  

Hail in some locations in New York and Pennsylvania got so deep that snowplows had to be used.... one of these places was the southern Tug Hill in places like Constableville, NY and Turin, NY, where the hail got several inches deep.   Places around Allentown, PA saw the same thing.  Berks County, PA was hit hard by the hail. The town of Wyomissing saw the worst of the hail damage. where the Berkshire Mall saw extreme damage to buildings and parked cars. There wasn't one car in the Berkshire Mall parking lot, that wasn't damaged...many of these cars were totaled.   Reading, PA also saw a lot of hail.  But gulf ball size hail fell across many places in NYS, PA, and DE. The largest hailstones of the day fell over Amsterdam, NY, where it was measured at baseball and softball size.

A US Air Jetliner also experienced issues with the hail. The plane was landing at Philadelphia International when it ran into the hail.... The hail cracked the windscreen.  

Northern NYS didn't only have hail to contend with. It also saw extremely heavy rainfall, as much as six inches fell in some spots. Between the hail and the heavy rains, flash flooding became an issue. In Port Leyden, NY a road collapsed due to flash flooding.

The supercell that dropped all the hail in Pennsylvania produced a tornado warning once it had moved into Delaware.   

The National Weather Service issued a tornado warning for northwestern Kent County at around 4:30 p.m. to  5 p.m., The NWS issued a second tornado warning for central Kent until 5:15 pm, when a funnel cloud was observed to touch down near Marydel, DE.  

The tornado caused a lot of damage. Two people who lived in a mobile home in western Kent County were injured, when the tornado demolished the trailer. The man was found under a pile of debris in the bedroom, he received numerous  cuts and abrasions, His wife was also injured while in a utility shed behind the mobile home.  The storm also trapped two motorist when high winds toppled utility poles and electric wires. They had the presence of mind to stay in the vehicle, until power was cut by emergency responders.  

The NWS Mount Holly confirmed the tornado was a high end EF1 with maximum winds  rated at 105 mph.

About an hour before the tornado in Delaware. The most impressive supercell of the day was moving southeast through Schenectady County about ten miles from Amsterdam, NY.  As already noted, the cell was dropping very large hail, and it was also producing damaging wind gust, Damage was reported around Gloversville and Johnstown.  The terrain in eastern New York State helped enhance shear at the surface.  At 3:37 pm the NWS issued a tornado warning for  several places including  Duanesburg, NY, Just to the west of  Schenectady.  The tornado was moving southeast at about 20 mph. The storm had  a very impressive inflow notch (hook echo)  on its southwest side.

As the supercell move slowly to the southeast, there was a very tight velocity couplet. Here is a scan of the cell as it was approaching Duanesburg. The image shows gate to gate shear at around 120 knots. 

There isn't much doubt that a tornado was on the ground. Here is another image showing a debris ball as the cell moved over Duanesburg, this confirms that there was indeed a damaging tornado on the ground. 

The tornado caused severe damage to several homes and buildings, including  The town of Duanesburg Volunteer Ambulance Corps building where it ripped a wall down.  On Route 7 the storm hit and damaged a family restaurant.

 Ambulance Corps building.

A house owned by Margaret Krylowicz on Route 20 was completely destroyed by the tornado. 

 As the tornado moved over Interstate 88 it overturned two tractor-trailer trucks.  

The tornado kept moving southeast into Albany County crossing  numerous roads, causing lots of tree damage. The tornado missed Rick Smith's (a Facebook friend and a fellow weather enthusiast) house by a mere half mile........The cities of Albany and  Schenectady dodged a bullet with this storm.

NWS Albany confirmed the tornado was a EF3 with maximum winds rated at 140 mph, with a damage path one quarter of a mile wide, and a damage path length of seven miles.

The National weather service's communication issue.

Right in the middle of the severe weather outbreak hitting the Northeast and Mid Atlantic. The NWS warning dissemination system failed. This system is critical to the NWS's mission to protect life and property. The NWS said in NWS Chat and a email, "It appears that all NWS warnings did not properly disseminate during the outage, and significant severe weather was occurring during the outage," Basically this means very few people were getting timely weather warnings and alerts. Most media outlets such as TV and radio  get their warning information from the NWS, with the system down for half an hour( around 4:00 pm - 4:37 pm)   they weren't getting the Vital data.  

Online radar data was also effected. 

The system went down as dangerous severe thunderstorms were impacting the Northeast. Such as  a damaging tornado heading for Albany, NY...and possible tornadic supercells heading for Washington DC.

There can be little doubt, that some people were caught unaware as dangerous weather was heading their way....people caught in situations like supercells dropping large damaging hail.

 The really scary question is, why doesn't the NWS have the equipment and resources it needs to carry out its mission? Will something like this happen again? Will people die who rely on the NWS alert messages?

The NWS is staffed by great meteorologists, who are dedicated to their job. I'm sure they're as frustrated with this issue as I am.

Wednesday, May 7, 2014

The EF Scale.

I've been fielding a few questions on the EF scale.   So I thought I would do a little write-up about the the EF scale.  I will briefly discuss the F and EF scale, discuss why the Vilonia, Arkansas tornado wasn't an EF 5, and discuss a weakness in the EF scale.

Outbreaks such as the recent April 27-30 2014 tornado outbreak,  often sparks a lot of controversy in social media and weather discussion sites revolving around the damage left behind.  The conversation is normally about why was a tornado rated a particular way?

Admittedly, I know it's hard not to look at pictures and video of severe damage left in the wake of a tornado. We try to understand the  kind of force it takes to reduce towns and cities to churned  rubble.  A violent tornado destroys in seconds, things we build, things that we think are powerful and strong.  I've seen the devastation up close and personal. I've stood there amid devastation, looking in every direction and seeing nothing but desolation, seeing a landscape that looks straight out of the gates of hell. I too can only imagine the amount of force brought to bear on the world of humankind.  

This was the  reason University of Chicago meteorologist Tetsuya "Ted" Fujita, in collaboration with Allen Pearson director of the National Severe Storms Forecasting Center, developed the original Fujita scale. To try to understand the inconceivable power of the tornado.  The Fujita scale, or F-Scale, a system of classifying tornado intensity based on damage to structures and vegetation.  The F-scale used a scale of F0 to F5, with the least intense tornadoes rated "F0" and the most intense rated "F5.".  It was used by the National Weather Service from 1973  until 2007, when the Enhanced Fujita scale (EF scale) was officially adopted.
If you want to read about Dr  Fujita, Tim Marshall wrote  a tribute to this remarkable man. You can find it here. 

Here is a video about Dr. Fujita.

Why change the EF Scale?

Over the years, the F-Scale revealed some weaknesses. The estimation of wind speed in relation to damage was difficult to apply with no damage indicators. It made no allowance for difference in construction.  Often the assessment was based on the worst of the damage in an area, even if it was just one building or one house. Another weakness of the Fujita scale, was that it overestimated wind speeds greater than F3. The old F-scale also placed too much emphasis on estimated wind speeds.



Because of these flaws a change was needed . The EF scale was formulated by a team of meteorologists and engineers called together by the Wind Science and Engineering Research Center at Texas Tech University. The main point of the enhanced scale, was that it would continue to maintain and support the original database. There was to be conformity between the original Fujita scale and the Enhanced Fujita scale. A few additions were to be made as well. The Enhanced Fujita scale would have a more consistent assessment of damage.  It would include more detail on damage, , this would include photos and examples, not only structures, but vegetation as well, the EF scale would  allow for different types of construction, note the mean and maximum damage width, the latitude and longitude of the starting and ending point of the damage path, who was on the survey,  time spent conducting the survey,  a PC-based expert system, and enhanced training materials.



It should be noted that the Enhanced F-scale is a set of wind estimates (not measurements) based on damage. It uses three-second estimated gusts estimated at the point of damage. Important: The 3 second gust is not the same wind as in standard surface observations. Standard measurements are taken by weather stations in open exposures, using a directly measured, "one minute mile" speed. These estimates vary with height and exposure. Forensic meteorologists use 28 damage indicators and up to 9 degrees of damage to assign estimated speeds to the wind gusts.

The 28 Damage Indicators used in applying the Enhanced Fujita Scale:
1: Small barns, farm outbuildings
2: One- or two- family residences
3: Single-wide mobile home
4: Double-wide mobile home
5: Apartment, condo, townhouse (3 stories or less)
6: Motel
7: Masonry apartment or motel
8: Small retail building (fast food)
9: Small professional building (branch bank)
10: Strip mall
11: Large shopping mall
12: Large, isolated retail building
13: Automobile showroom
14: Automotive service building
15: School- 1 story elementary (interior or exterior halls)
16: School- jr. or sr. high school
17: Low-rise (1-4 story) building
18: Mid-rise (5-20 story) building
19: High-rise (over 20 stories) building
20: Institutional building (hospital, university)
21: Metal building system
22: Service station canopy
23: Warehouse
24: Transmission line tower
25: Free-standing tower
26: Free standing pole (light, flag)
27: Tree- hardwood
28: Tree- softwood

Each one of these indicators have a description of the  typical construction for that category of indicator. Then, the next step is to the determine  the degree of damage. Each degree of damage in each category is given an expected estimate of wind speed, a lower bound and upper bound wind speed.

Here's a link to the 28 damage indicators so you can see how all of this is applied. The Storm Prediction Center website.

Why wasn't the Vilonia, Arkansas tornado rated an EF5?

The damage in Vilonia was very severe and extensive. Many buildings were damaged or destroyed.  In the emails and instant messages I received,   Several  noted  that the severe damage in Vilonia was indicative of EF 5 damage, some even saw places where slabs were all that was left.  And that is very true.  So if the houses were completely swept away, then the assessment teams must have gotten it wrong.  Isn't slabs left where houses once stood EF 5 damage? the quick answer is yes. BUT the not so quick answer is maybe.

When the damage assessment teams out of  NWS Little Rock looked at the damage close up, they found  poor construction in several buildings.   Some of these buildings had even been built after the Super Outbreak of 2011. what the teams found was homes secured to the foundation with cut nails instead of anchor bolts, or they had anchor bolts, but no washers or nuts holding the house in place.

Photo on left shows the foundation was held down with cut nails. The photo on the right, shows the lack of washers and nuts holding down on the Sill Plates of the house. Photo Credit NWS Little Rock.

Without anchor bolts the buildings just didn't have the strength to resist the sliding and lifting loads that result from strong winds.  Therefore the lack of anchor bolts meant much less wind force was needed to  sweep complete houses away.  Because of this the tornado was rated EF 4 instead of EF 5. 

Under the old F scale the Vilonia, Arkansas tornado would most likely have been rated an F5. But because the new EF scale pays attention to quality of construction it caught this oversight and gave the tornado an appropriate rating.   This is why you can't rate tornado damage from pictures or video.

Problems with the EF Scale.

IMO, the EF scale focuses to much on structure damage.  For trees, it only allows for soft wood or hard wood.

There is no doubt that rural tornadoes strike far more trees than human made structures. So if the NWS wants to assign the most realistic wind speed estimates along the damage path, it only makes sense that trees make up part of the damage indicators. However out of the 28 damage indicators only two allow for tree damage.  This is much too generalized to capture variability in tree strength across different species.  

Examples of hardwood trees would be oak, birch, maple, anacua, cherry, elm, ash. Examples of softwood trees would be pine, fir, spruce, cedar, hemlock and cypress.

I've walked several damage paths.  I can tell you, I've seen many examples of how tornado damage differs among different types of  trees.  Each species has different root structures, leaf design, and type of wood grain. Therefore , it only makes sense that each would react to strong winds differently.  A softer hardwood would be more susceptible to breakage  and debarking, than a harder type of softwood., types of roots and leaf structure would have a lot to say about why a tree became uprooted, different types of trees have different types of bark characteristics, each becoming debarked in different ways.   Because of all of these things,  tree species has a lot of potentially very useful information to pass along.  Understanding and noting  damage to various tree species would not only be useful in rating rural tornadoes. It would be one more clue to help assign a rating in more urban areas, and residential neighborhoods.    


Well that should give everyone a better understanding of the EF scale. If you enjoyed this post, here is another you might like. Tornadic winds versus Straight line winds.