After such a memorable hurricane season last year which featured Hurricane Sandy, many of us will be taking note of the National Hurricane Center's Atlantic hurricane season outlook which they issued today. Here is a quick look at the number of named storms, hurricanes and major hurricanes (Category 3 or higher) they expect this season.

NOAA Article Here

From NOAA,

"For the six-month hurricane season, which begins June 1, NOAA's Atlantic Hurricane Season Outlook says there is a 70 percent likelihood of 13 to 20 named storms (winds of 39 mph or higher), of which 7 to 11 could become hurricanes (winds of 74 mph or higher), including 3 to 6 major hurricanes (Category 3, 4 or 5; winds of 111 mph or higher).

These ranges are well above the seasonal average of 12 named storms, 6 hurricanes and 3 major hurricanes."

Reasons for the above-average activity are warmer than average sea-surface temperatures in the tropical Atlantic, near-normal sea surface temperatures in the equatorial Pacific, and the continuation of the overall atmospheric climate pattern responsible for the high activity era since 1995.

How does this compare to last season? Here was the National Hurricane Center's 2012 season recap.

"For the 2012 Atlantic season, 19 named storms formed, of which 10
became hurricanes. One of those hurricanes, Michael, reached major hurricane status. Activity fore 2012 was well above the 30-year (1981-2010) average for named storms and hurricanes, and below average for major hurricanes. The 1981-2010 seasonal averages for the Atlantic Basin are 12 named storms, 6 hurricanes and 3 major hurricanes."

Above is a look at the storm names for the 2013 Atlantic Hurricane Season. You can find the list of storm names for the next few years here.

Continue Reading

With advancements in radar technology, forecasters have a greater ability to analyze storm structures.  Even though there is still much more to be researched and explored, meteorologists can get a good indication of the height, size, and intensity of a particular storm cell, which then leads to better warnings to the public.  The 3D visuals in the video below recap the evolution of the devastating tornado in Moore, OK Monday. 

The Moore, OK tornado, at one point, reached the highest tornado classification, EF5 status.  EF4 and EF5 tornadoes make up only 1% of all the tornadoes in the U.S.

Continue Reading

Donations:

I wanted to share this first and foremost. You can donate to the Red Cross primarily but if you search around, some businesses will even match your donation. One of those is the National Storm Shelters LLC who tweeted earlier that they will match donations sent through their Red Cross Page Here.

Other Red Cross Resources:

Find more quick help resources from the Red Cross here. Did you know there was a tornado app from the Red Cross to let people know you are safe after the storm has passed?

Text REDCROSS to 90999 to make a $10 donation.

Donating Blood:

The Red Cross stands ready to help meet the blood needs of patients in and around Oklahoma City if needed, and there is currently enough blood on the shelves to meet patient demands. The Red Cross is a secondary supplier of blood products to hospitals in the affected area in Oklahoma. People with type O negative blood are encouraged to give blood when they are able. All eligible blood donors can schedule an appointment to give in the days and weeks ahead by calling 1-800-RED CROSS or visiting www.redcrossblood.org to help ensure blood is available when people need it.

Here is a look at the track of the tornado. It first touched down at 2:56pm and finally roped out at 3:36pm with a path length of 17 miles and a preliminary damage rating at EF-4 intensity.

The National Weather Service office in Norman, OK is continuing to do the damage survey today and will probably continue working on it tomorrow before putting out the final assesment. They will continue to keep updating their page on the tornado here.

You can also stay up to date with the NWS Norman Public Information Statement found here. The latest statement continues to show EF-4 damage with estimated winds of 190 mph, though they said they will continue to update as the teams complete their surveys.

Right after I write that, this was put out by the NWS Norman twitter page, "@NWSNorman: At least one area of EF-5 damage was found by survey crews. Details to follow later. #okwx", so updates will be made soon.

List of F5 and EF5 tornadoes since 1950 - Note how the map is cut off as there haven't been any reported that strong east of the Appalachians.

Photos:

Here is a look at the tornado as it first developed and rapidly intensified from a storm chaser and former NWS Huntsville Meteorologist.

Continue Reading

This is a bit of a tough post to make after watching everything yesterday leading up to the tornado and then watching the tornado itself form just southwest of Oklahoma City.

By the time the storm reached Moore, Okla., the storm was an absolute monster. The tornado was up to a mile wide and the winds were possibly up to 200 mph, according to preliminary reports from the National Weather Service.

Unfortunately this storm has taken 24 lives so far (at least not the 91 reported by some outlets earlier today) and just looking at the damage I would imagine there still may be more found today.

Similar tracks of the 1999 and 2013 Moore Tornadoes

Here is a look at the path of this tornado compared to the one that struck the same area on May 3, 1999, which was also classified as a F-5 (Before the EF scale was used) and had winds recorded at nearly 300 mph from a nearby Doppler on Wheels.

It's crazy how these two storms paralleled one another before crossing paths with nearly the same strength 14 years apart.

Comparison of the 1999, 2003 and 2013 Tornado Tracks (Credit: Weather Decision Technologies)

Another view of the track compared to the 1999 tornado as well as the 2003 F-4 tornado shows just how violent tornadoes have been in that area over the past 14 years.

Reflectivity image as the tornado moved into Moore. Note the giant debris ball which is the pink circle entering Moore.

Above is what I was looking at as this storm was at its height. This is the reflectivity image from the Oklahoma City radar located just southeast of the storm.

If you take a look at the image you will note the big pink to purple circle on the radar image heading into Moore. When I saw this, I was terrified, because that is actually debris suspended in the air that the Doppler is seeing. You can clearly see the classic "hook echo" to the storm, but it's that debris signature that gives you an idea of just how strong this thing was.

Velocity image from the ktlx Doppler radar east of Moore

Above is a look at the velocity image, which shows winds going towards the radar in green and blue and winds going away from the radar in red. This is definitely one of the strongest velocity couplets I've seen through my radarscope app. This is showing winds in excess of 150 mph and possibly up to 200 mph which would be in an EF-4 range.

It's just unbelievable strength and power in this storm, and something that you most likely will not make it through unless you are underground or in a storm shelter.

Here are a few videos I've seen from YouTube of the tornado.

The storm threat isn't done yet. There is still a moderate risk for severe storms today stretching through Texas, Louisiana and Arkansas and a slight risk through much of the Midwest. Be sure to heed warnings and be ready for severe weather again this afternoon.

Severe Storm Threat Today

Continue Reading

May might have started out slow, but tornado season is now in high gear. A major outbreak over the weekend left dozens homeless and killed at least one person. 

Hardest hit was Shawnee, Okla., where a large, violent tornado struck a mobile home park leaving nothing standing. Here is video from our ABC affiliate of the damage.  That twister, among several others, was caught on tape by stormchasers. 

The severe weather had been advertised for days. All of the elements came together like a textbook example of how warm moist air from the Gulf of Mexico meets up with cooler, drier air from the north. Strong winds turn with height in the atmosphere and  the winds also increase in speed with height.  

This helps provide the support needed for major tornadoes of EF3 or more. 

Severe Weather Elements, Accuweather

The Shawnee tornado is yet to be rated on the Enhanced Fujita Scale, but the National Weather Service is on the scene Monday to do a survey.  In all, there were around 50 preliminary reports of tornadoes this weekend and many, many more reports of wind damage and hail stretching from Oklahoma to Minnesota. Here are the storm reports from just Sunday:  

Storm Reports Sunday, May 19, 2013

Unfortunately, more tornadoes are expected this afternoon and evening. The Storm Prediction Center has issued a "Moderate Risk" for tornadoes in some of the same areas of Oklahoma.  A slight risk stretches into the Great Lakes. 

Severe Weather Outlook Monday

 

Despite the large number of tornadoes this weekend, we are still far below the seasonal averages. May is usually the month with the highest count of tornadoes in the United States. Check out this graphic from the Storm Prediction Center. Also, notice the high count in 2011. 

Preliminary 2013 Tornado Count

As for us in D.C. Maryland, and Virginia, we tend to see more frequent violent weather in July and August, but tornadoes can and do happen in May and June.  Remember, it's not the number of tornadoes that develop, it's the potential of just one of them impacting you.

Continue Reading

LIVE DOPPLER | SOUTHERN MD RADAR

The Storm Prediction Center has collaborated with the National Weather Service office in Sterling, VA today to upgrade parts of the D.C. area to a Slight Risk for severe storms. This just highlights a greater potential for severe weather in the area highlighted below. The best chances for severe storms will actually be in the southern part of the blue circled area.

Slight Risk Upgrade by the SPC and NWS Sterling

Damaging winds will still be the primary mode of severe weather in any storms that form and location should be along and south of the frontal boundary. A lot of lightning has also been in the storms that have developed around Charlottesville.

Areas south of Fredericksburg in VA closer to Central Virginia and the Northern Neck will have the biggest threat for any severe storms. Stay tuned this afternoon for further updates on our homepage, through social media and on ABC 7 News at 5pm and 6pm.

Continue Reading

The weather pattern across the D.C. area, and much of the East Coast, has been plagued by this pesky upper level low the couple of days.  Clouds, showers, and muggy conditions.  Today the metro region finally broke out into some sunshine, but with unstable conditions, heavy showers and thunderstorms developed.  Even though there was some very heavy rain and even reports of small hail, these storms did give way to some neat looking skies.  Check out this timelapse from the WeatherBug camera on top of our ABC7 studios in Arlington.

Continue Reading

After an absolutely gorgeous first weekend of May, the start of the work week weather took a turn in the opposite direction.  Unfortunately, for those of you not a fan of the grey skies and showers, this weather pattern is here to stay... at least for a good chunk of the work week.  So why the unsettled weather?  Let's explore.

Check out yesterday's satellite image.  Notice the big "swirl" from space.

GOES

I went ahead and drew the features that are present from this system.  The 'L' represents the area of low pressure that is spinning, counterclockwise, over the southeast US.  The blue arrows indicate the onshore, or easterly, flow bringing in Atlantic moisture to the mid-Atlantic.  Air circulates around the low in this counterclockwise fashion.

The low will track northeast over the coming days, but will be slow to do so.  Take a look at the upper level low from about 18,000 ft (500mb).  This is a simulation of where the low will be later this afternoon. 

NCEP

As the low tracks northeast, cloudy and damp weather will persist across the region.  It won't be a complete washout each day this week, but scattered showers will be possible through at least Thursday.  Check out the Weather Prediction Center's quantitative precipitation forecast through Thursday evening.  This forecast shows between 1 and 2 inches of rain over our region, with locally higher amounts over southwestern VA.

WPC

With moderate rain possible over an extended period of time, the National Weather Service has issued a flood watch for parts of the Shenandoah valley through late tonight.  Remember, if you encounter standing water, never drive through it. The latest Flood Watch was extended north into Clarke, Frederick (VA), Hampshire and Mineral Counties as well.

By late Thursday, the low weakens its grip and gets caught back in the overall pattern.  Compare the 500mb heights in this forecast (below) for Thursday night to the same map shown above.  Notice there is a slight dip in the wave pattern, but nothing cut-off (like in the similar image a few graphics up). 

NCEP

For us, this means a less unsettled weather pattern.... sort of, for Friday at least. High temperatures will climb to near 80 degrees by the end of the week, which could initiate a few airmass thunderstorms to develop, but nothing widespread.  A cold front will then slide through this weekend bringing continued chances for showers but drier and slightly cooler air can be expected for early next week. 

Continue Reading

Seventy-four tornadoes were spawned on May 3, 1999 including a F5 tornado which struck the suburbs of Oklahoma City. This tornado tracked along a 38-mile path for nearly an hour and a half from Chickasha through south Oklahoma City and the suburbs of Bridge Creek, Newcastle, Moore, Midwest City and Del City. The outbreak caused 46 deaths, 800 injuries, nearly 8000 homes damaged or destroyed and over $1.5 billion in damages.

Meteorologist Devon Lucie here.  I was a meteorology student at the University of Oklahoma that day, and it's one I'll never forget.  At that time, the school of meteorology was located on the top floor of Sarkeys Energy Center at the Northeast end of the campus in Norman, OK, which you can see on the map, is just southeast of the track of the infamous tornado. 

I was on the 12th floor in a room with other students when I witnessed the tell-tale flashes of power lines and transformers failing as the tornado ripped through Moore.  The massive wedge tornado also was crossing over I-35 at that time where a number of people lost their lives while trying to shelter from the twister during rush hour.  The highest wind speed recorded by the Doppler on Wheels found winds of 298mph, which is still the highest wind speed ever recorded on the planet.  It was an awesome, yet horrfying sight... one I never hope to repeat again. 

Outbreak Map from NWS Norman, OK

NOAA National Severe Storms Laboratory webpage on the Outbreak here

NOAA National Weather Service Norman, OK webpage on the Outbreak here

Meteorological Summary of the Event Here

Continue Reading

Happy May Day everyone.  The month known for blooming flowers after April showers is upon us.  When I think about the month of April, my mind was thinking "cool" just like March.  But, when I took a look at climate records, we were actually a bit on the plus side. The month ended up 2 degrees above average.  The 91 degree day on April 10th helped to skew us on the plus side.  15 days in April were above average and 14 days were below.  As we turn the calendar to the month of May, we are right on track.  

May Averages

The average high for May first is 71 degrees and we will be near that all week.  By the end of the month, we warm up with an average high of 80.  Longer days help bump up the temps this month. Here's a look at the sun on the horizon around 5:30 this morning.

WJLA Rooftop View at 5:30 a.m.

 Sunrise was officially at 6:10a.m. Today, we will get 13 hours and 51 minutes of sunshine with sunset after 8:00 P.M.  While April is known for it's showers, May actually gets more rain on average around 4" for the month.  In addition, it's time to start thinking about severe weather safety plans and rules.  May, June and July are the peak severe weather months in the Mid-Atlantic. The Stormwatch 7 team of meteorologists will always be here to help keep you safe when dangerous weather approaches.

Continue Reading