B_Rock's Blog

This occured on March 4, 2008 around 4:54 pm

NWS STORM SURVEY FINDS AN EF-0 TORNADO IN NORTHERN ALAMANCE
COUNTY...

AN EF-0 TORNADO TOUCHED DOWN ONE HALF MILE SOUTH OF WILLIE PACE
ROAD... NEAR UNION RIDGE ROAD IN NORTHERN ALAMANCE COUNTY YESTERDAY
AFTERNOON...MARCH 4TH 2008. WINDS WERE ESTIMATED TO BE BETWEEN 70
AND 75 MPH. THE TORNADO TRACKED TO THE NORTHEAST AFTER TOUCH DOWN...
AND CONTINUED FOR APPROXIMATELY 5 MILES... WITH A DAMAGE WIDTH OF
APPROXIMATELY 100 YARDS WIDE. THE TORNADO WAS ON THE GROUND IN
NORTHERN ALAMANCE COUNTY FOR APPROXIMATELY 2 MILES AND CONTINUED ON INTO CASWELL COUNTY FOR APPROXIMATELY ANOTHER 3 MILES. THE TORNADO CAUSED DAMAGE TO SEVERAL STRUCTURES NEAR WILLIE PACE ROAD IN NORTHERN ALAMANCE COUNTY AND DESTROYED A BARN NEAR VINSON ROAD NEAR THE ALAMANCE/CASWELL COUNTY LINE. NUMEROUS TREES WERE DOWNED ALONG THE TRACK. IN ADDITION...A COUPLE OF HOMES WERE DAMAGED AND NUMEROUS TREES WERE DOWNED IN CASWELL COUNTY. FURTHER INFORMATION FOR CASWELL COUNTY CAN BE FOUND IN STATEMENTS

This map is a "very rough" image that I made of the estimated path of the tornado.

<a href="http://s258.photobucket.com/albums/hh269/davidd2
172/?action=view&current=AlamanceCountyTornadoPath.png<
/a>" target="_blank"><img src="http://i258.photobucket.com/albums/hh269/davidd21
72/AlamanceCountyTornadoPath.png" border="0" alt="alamance county tornado 3_4_08"></a>

 

March 2-8 is NC Severe Weather Awareness Week. There will be a specific topic of discussion each day that I will post on this blog entry. Also Wednesday will be the annual state-wide tornado drill. This along with our slight potential of severe weather on Tuesday evening should get everyone to begin thinking about what you would do in case severe weather strikes your area. With winter storms and tropical systems there's always lots of advance notice. Severe storms however may fire up quickly and unexpectedly with little to no warning. Here now is today’s entry:

Each day we will cover a different topic. Today we will define exactly what is a severe thunderstorm?

The last five years alone have seen a large amount of severe weather in North Carolina. Over the last five years there have been nearly 5000 reports of large hail and damaging wind statewide resulting in over thirty two million dollars in damage. Severe thunderstorms are also responsible for injuries and even deaths in the state resulting from lightning and high winds. The severe thunderstorm season in central North Carolina typically starts in March and does not end until late in the fall.

...severe thunderstorms...

The National Weather Service considers a thunderstorm severe if it produces a tornado, hail at least the size of a penny and or winds of 58 mph or greater. These minimum wind and hail parameters are the National Weather Service's warning criteria for severe thunderstorms. It is worth noting that the National Weather Service does not issue warnings for lightning and given the deadly nature of lightning you should always be aware of the lightning danger anytime a thunderstorm is nearby. In 2007 warnings issued by National Weather Service offices provided an average of sixteen minutes lead time for severe thunderstorms with a detection rate of nearly ninety percent.

...large hail...

In the last 5 years severe thunderstorms in North Carolina have  produced hail as large as tennis balls and even baseballs across the piedmont and eastern North Carolina. Just 2 years ago baseball size hail struck Eastern North Carolina resulting in over one hundred thousand dollars in damage. Back in 2005 hail of nearly 4 inches in daimeter caused damage across the triangle. While hail is not usually life threatening, these large chucks of ice when driven by strong winds cause serious damage to roofs, automobiles, and crops. Hail season in central North Carolina typically runs from mid March through early July, typically peaking in May.

Hailstones grow in thunderstorms with strong updrafts. These strong upward moving currents of air keep the ice suspended inside the thunderstorm...allowing the chunk of ice or hailstones to grow larger and larger. Once ice stones become too heavy for the updrafts to keep suspended...they fall to earth as hail. Thunderstorm updrafts which show signs of rotation on radar are very effective at suspending hail since the internal velocities in rotating updrafts are higher that those of non rotating updrafts.

...damaging wind…

Strong gusts of wind from a thunderstorm called downbursts or straight line wind, are another serious danger. These gusts of wind rush down from the sky sometimes reaching speeds in excess of 100 mph. Thunderstorm wind of this magnitude can impact large areas creating widespread damage. Damaging straight line winds can even cause damage equivalent to that of a tornado. Lines of well organized thunderstorms...called squall lines... Occasionally move across central North Carolina in the spring and early summer. These dangerous storm systems can be very explosive racing across the state at over 50 mph creating widespread wind damage over entire counties.

Damaging wind events in central North Carolina typically start as early as mid March and run into August. Damaging thunderstorm wind events are most notable from May through early August which is much longer than the typical severe hail season.

...safety...

You can protect yourself during thunderstorms by remembering this phrase…hide from the wind and lightning. Stay away from windows when storms approach and seek shelter in an interior bathroom or closet when the wind really starts to blow. Your best line of defense against severe thunderstorms...is to stay informed. There are so many great outdoor activities across the state of North Carolina and severe weather can bring a quick end to a days pleasure. Listen to NOAA weather radio, television or local radio for the latest forecasts and possible threat of thunderstorms and severe weather. If warnings are issued...take action and protect your family and property. Remember being safe is a lot better than being sorry.

SkywarnTM at WFO Raleigh
NWS Watch, Warning, and Advisory criteria
What's New:We need your rain, snow and hail reports. Interested in reporting precipitation more frequently?  Join the CoCoRaHS (Community Collaborative Rain, Hail and Snow) weather spotter network. 

Interested in receiving the Raleigh NWS newsletter "Changing Skies" along with other SkywarnTM Spotter updates and news via email. Just send an email to jeff.orrock@noaa.gov and ask to receive the office newsletter via email.
Local SkywarnTM Groups:

Central Carolina SkywarnTM serving the Eastern Piedmont and Coastal Plain
Triad SkywarnTM serving the Northwest Piedmont

Training Sessions:Online Weather School

02/19/08 830am-11am SkywarnTM - BASIC Spotter Training Moore Carthage - (105 W. Saunders St, Moore County Emergency Services) 02/21/08 7pm-9pm SkywarnTM - BASIC Spotter Training - Open to the public Moore Carthage -( Moore Co Agricultural Center) 03/08/08 930am-1130am SkywarnTM - Basic Spotter Training & Radar - Open to the public Durham (CISCO at RTP) CISCO, 7025-5 Kit Creek Rd -(Registration is required (18 years and older). 03/08/08 1pm-3pm SkywarnTM - Advanced Spotter Training - Open to the public Durham (CISCO at RTP) CISCO, 7025-5 Kit Creek Rd -(Registration is required (18 years and older). 03/10/08 730pm-9pm SkywarnTM - Advanced Spotter Training - Open to the public Forsyth Winston-Salem -( Northwest Chapter of the American Red Cross) 03/12/08 2pm-4pm SkywarnTM - Radar Interpretation & Advanced Spotter Training - Open to the public Guilford Greensboro -( Guilford County Emergency Management
1002 Meadowood Dr.) 03/12/08 7pm-9pm SkywarnTM - Advanced Spotter Training - Open to the public Guilford Greensboro -( Guilford County Emergency Management
1002 Meadowood Dr.) 03/13/08 7pm-9pm SkywarnTM - BASIC Spotter Training - Open to the public Edgecombe Tarboro -(Edgecombe County Building Auditorium)

 

 

View the page at http://www.erh.noaa.gov/rah/skywarn/index.php#training

The *surprise* snow that fell the evening of the 13th has been under some mild scrutiny. Why wasn't this predicted? What happened to catch us so off-guard? The official word from the NWS has not yet been posted, but here's a chart of total snowfall:

  

 

Now how did this happen? Well, I'm not up to date on all the jargon used by meteorologists, but the bottom line is that winter weather, especially here in central NC is very difficult to predict. And when something is forming and developing right on top of us, it makes it even more challenging. Also water content is a big deal in snow forecasts. For example if an on-air weather personality predicts 1/4" of rain and we actually get 1/2" of rain, it's not really a big deal to any of us right? Remember to figure water content in snow, 1/10" of water equals 1" of snow. (On average of course, some snows are wetter, some are drier) So if that same prediction of 1/4" of liquid (which would be 2-3" of snow) suddenly became 1/2" of liquid (then it would be around 5" of snow) Then all of a sudden the public goes nuts and demands the collective heads of the local weather forecasters.

 

 

The situation with this system was that some models predicted that some lingering moisture could interact with the cold air as it made its way into the piedmont. I don't think any models picked up on a weak low pressure system rapidly developing behind the cold air however. When the NWS Raleigh updates their past events history for this system, I’ll post it.

 

 

 

 

 

 

A major springtime-like severe storms outbreak has occurred over the last 18 hours in Arkansas, Tennessee, Mississippi, Kentucky, and parts of Georgia and Alabama. As I'm posting this, the numbers continue to grow. 337 severe weather reports with 68 of those being tornado reports. At least 44 people have been killed and that number is likely to rise. 

 

 

The dead included 24 people in Tennessee, 13 in Arkansas, and seven in Kentucky, NBC News said. Among those killed were Arkansas parents who died with their 11-year-old in Atkins, about 60 miles northwest of Little Rock.

 

The severe potential for our area seems to have lessened and this storm system is slowing down a bit more than previously anticipated, and while a widespread outbreak here in central North Carolina is unlikely, we could still see an isolated wind gust of over 50 - 60 mph. The best advice I can give is for everyone to simply keep monitoring this rapidly-changing system and go ahead and have a plan in place of what to do and where to go should severe weather threaten. It looks like the timing of these storms will be around the 4pm to 11pm time frame, but even that could change. Listen to your weather radios, radio stations in your car (101.1FM is very good for putting weather warnings out over the air) and of course our good friends at WGHP will keep us informed. On a side note, those of you with weather alert radios (which should be everyone) Here is a statement regarding the tests normally done on Wednesdays.

 

.... Routine weekly test postponed until Thursday...
Due to the threat of severe weather today the routine weekly test of the
NOAA Weather Radio tone alert feature has been postponed. Instead... the test will be conducted tomorrow between 11 am and noon.

 

Everyone please keep safe out there and remember and lift up a prayer for those suffering and for those who have lost loved ones in this unusual wintertime severe weather outbreak.

 

 

 

There is a new all-volunteer network for weather watchers that was launched in North Carolina back in September of 2007 that you may want to look into. It's called the Community Collaborative Rain, Hail and Snow Network, or CoCoRaHS for short. CoCoRaHS, (No it's not a chocolate kids cereal) is a unique, non-profit, community-based network of volunteers of all ages and backgrounds working together to measure and map precipitation (rain, hail and snow).   By using low-cost measurement tools, stressing training and education, and utilizing an interactive Web-site, their aim is to provide the highest quality data for natural resource, education and research applications. I personally have been a member since the start of this year, and it has been a blast.

What's required? You need to have daily access to the internet; you need to be able to report your daily data around the same time each day, i.e. 7am, 8am, etc... And finally you need to purchase a specific rain gauge for around $30. The reason for the latter is that all rain gauges are not created equal, and the one they recommend has been tested and approved by the Colorado Climate Center.  There is much more info here at http://www.cocorahs.org/Content.aspx?page=aboutus

 

 

It's a fun way to report daily directly to the National weather Service and for you at your own home to really make a difference in your community and nationwide, as lately there are several national organizations that are using this data.

 

 

Anyone from any county can be used but specifically there are exceptional needs for new volunteers in the following counties:  Davie, Montgomery, Randolph and Rockingham. These counties are currently unrepresented in the CoCoRaHS network, and most other counties have only 3-5 volunteers per county, so all you weather nerds and geeks out there, jump into this if you like. It's Fun! I'll answer any questions I can via this blog.

 

 

 

....(I've always liked hearing these things called "events". It's like, "A snow event in North Carolina? Where do I get tickets for that!?")

 

After today's wimp of a "storm" came through, (hey, at least there was enough rain to wash all of the 4 layers of salt & brine the road crews put on the roads... talk about overkill!) I have been watching the short-range models, and Saturday (Jan 19th) is looking more and more interesting!

As it looks now, there would be plenty of cold air in place for all precip to be snow. No mixed bag BLEEP like today.  The big question is going to be the track of the low pressure that as of now, hasn't even developed, but the initial model run has it coming up the SE coast and being able to throw copius amounts of moisture into a cold atmosphere.  Here's the text from NWS that eludes to it.

MEANWHILE ... A STRONG SURFACE LOW WILL BE DEVELOPING OVER THE
WESTERN GULF COAST ON FRIDAY ... MOVING TO THE CENTRAL GULF COAST
BY SATURDAY.  THE STORM WILL BE INJECTING GULF OF MEXICO MOISTURE
OVER THE GULF COAST AND THE SOUTHEAST PRODUCING LIGHT TO MODERATE
RAIN OVER PORTIONS OF THE TEXAS AND LOUISIANA COAST WITH SOME
LIGHT RAIN INLAND BY FRIDAY EVENING.  BY SATURDAY MORNING A LARGE
AREA OF MODERATE TO HEAVY RAIN WILL DEVELOP FROM THE CENTRAL GULF
COAST NORTHEASTWARD TO THE SOUTHERN MID-ATLANTIC.  AS THE SYSTEM
BEGINS TO WINDUP ... MODERATE TO HEAVY SNOW WILL DEVELOP OVER THE
SOUTHERN/CENTRAL APPALACHIAN AND SNOW OVER THE TENNESSEE VALLEY
ALSO BY SATURDAY MORNING. 

See those words in that last sentence, "moderate to heavy snow"? Now THAT'S what gets me excited. I will of course be watching!

Fri Nov 30, 2007

U.S. weather experts posthumously upgraded Tropical Storm Karen to a hurricane as the 2007 Atlantic storm season drew to a close on Friday, making the year a near-average one for hurricane activity.

The U.S. National Hurricane Center, in a post-season analysis of Karen, said the storm briefly reached hurricane intensity on September 26, with winds of 65 knots, equal to 74.8 mph (120 kph) or just over the threshold at which tropical storms become hurricanes.

The upgrade of Karen took the 2007 season's hurricane toll to six, bang on the long-term average. The 14 named storms that formed exceeded the long-term average of around 10 for a six-month Atlantic hurricane season.

But most of the storms were short-lived, meaning the so-called accumulated cyclone energy index, which measures the collective strength and duration of storms and hurricanes, reached only about 82 percent of the 1951-2000 median, "the lowest observed since 2002," the hurricane center said.

Only one hurricane -- Humberto -- hit the United States this year. It was relatively weak and a far cry from the destruction wrought by hurricanes Katrina, Rita and Wilma in the record-setting season of 2005.

Two of the current season's hurricanes did reach maximum Category 5 strength on the five-step Saffir-Simpson scale of intensity.

Hurricane Dean in August slammed into Mexico's Yucatan Peninsula and killed around 27 people throughout the Caribbean, while Hurricane Felix in September plowed into Nicaragua, killing more than 100.

The season's deadliest storm was also its last, Hurricane Noel, which doused the Dominican Republic and Haiti and triggered floods and mudslides that killed more than 150 people in the neighboring countries.

Van, Emily... Your take on this?

Judge the 2007 Atlantic hurricane season by the 13 storms so far, and it looks like a relatively busy year. But look at the number of days a hurricane has swirled in the Atlantic, or use other measures of a storm season's ferocity, and 2007 has been surprisingly benign.

Hurricane experts had predicted the season to be above-average because of warm Atlantic sea surface temperatures, the continuance of a decades-long natural period of increased storm activity, and the development of La Nina weather conditions in the Pacific.

Many tropical waves, often a precursor of a tropical storm, developed in the Atlantic over the busiest weeks of the season between September and early October, and eight named tropical storms formed in September -- matching a record for the month.

But apart from maximum-strength Hurricane Felix, which slammed into Central America on September 4, most were exceedingly brief or weak, meaning September only registered 3.5 days with a hurricane.

One noted hurricane forecasting team at Colorado State University had predicted 20 hurricane days that month.

This year's storms caused relatively little damage and casualties especially compared to the havoc inflicted in 2005, when Hurricane Katrina flooded New Orleans, Wilma pummeled the Mexican resort of Cancun and Florida, and Rita hit the Texas-Louisiana border area.

The main reason for the low number of hurricane days this year has been high vertical wind shear -- the difference in windspeeds at different altitudes -- which tears storms apart while they try to form, hurricane experts said.

Scientists are puzzled. A periodic cooling in sea temperatures in the eastern equatorial Pacific, known as La Nina, is supposed to reduce shear over the Atlantic.

END OF SEASON SURPRISE?

The U.S. National Oceanic and Atmospheric Administration said on Tuesday the La Nina phenomenon had definitely kicked in and would be weak to moderate this winter.

That could make the end of the six-month hurricane season, which began on June 1, a little busier than one might otherwise expect because a normal increase in late-season wind shear might be suppressed by La Nina, experts said.

There have officially only been four hurricanes this season but many experts expect Tropical Storm Karen to be upgraded to a hurricane in a post-season analysis, pushing the number to five. The long-term average is for 10 to 11 named storms and six hurricanes per season.

But James Elsner, a Florida State University professor of geography who analyzes hurricane forecasting, said: "We are getting to the end. If something doesn't happen in the next two weeks it's basically over."

"I think what we have to question is why there was so much enthusiasm for this season (in terms of the activity predicted)," he said.

From a story on Yahoo weather...

A tropical or subtropical system could develop during the next couple of days near South Florida as a low-pressure area moves westward toward the Gulf of Mexico, the U.S. National Hurricane Center and other forecasters said Monday.(10-1-07)

Three computer weather models show the system crossing south Florida, then moving northwest in the eastern Gulf of Mexico before making landfall in the Florida Panhandle or along the Mississippi-Alabama coast.

A fourth model shows the system tracking north up the Florida Peninsula and into Georgia.

By late Tuesday into Wednesday, a large majority of weather models indicate the upper level low would supply enough energy to the surface and spark a storm system over western Cuba and adjacent areas of the Gulf of Mexico.

Another forecaster, AccuWeather, also predicted the South Florida system could develop tropical characteristics later this week and could intensify over the warm Gulf waters.

The NHC will name the next tropical storm (winds 39-73 mph) Noel.

TROPICAL OR SUBTROPICAL

A subtropical storm has high winds and thunderstorms near the outer edge of the system, while a tropical storm has high winds and thunderstorms near the center.

The biggest damage caused by a tropical system is usually near the center of the storm, while in a subtropical system the biggest effect is closer to the outer edge of the storm.

KAREN AND MELISSA

The remnants of Karen extend from the Leeward Islands (Virgin Islands, Anguilla, St Martin, Saba, Antigua, Barbuda, Saint Kitts, Nevis, Montserrat and Guadeloupe) eastward for several hundred miles. The NHC said upper levels winds were not favorable for redevelopment of this system.

The NHC also said there were no signs of redevelopment of the remnants of Tropical Depression Melissa, which was located about 825 miles west of the Cape Verde Islands and moving westward at about 10 to 15 mph.

 

from hurricanetrack.com:

The Hurricane Hunter plane went out and investigated the large area of showers and thunderstorms in the eastern Gulf of Mexico today and found a low pressure area without any deep thunderstorms. The entire weather system is still quite broad and should run out of time to get its act together before moving inland this weekend. For what ever reason, with the exception of Dean, Felix and a few hours for Humberto, this season just has something missing. Everything else that has formed has struggled and this system is no exception. None the less, in means very little anxiety for those who live near the coast- and that is certainly welcomed news. It seems that this system will bring rain to parts of the central and northern Gulf Coast region but that's about it. Unless some unforeseen force comes along and ramps this up, it will not be too big of a deal. Obviously, the NHC will keep monitoring it and I will do the same- posting regular updates here as needed. The remainder of the tropics are fairly quiet with no threats to land areas anytime soon.

from Hurricanetrack.com...

Just a few weeks ago, it seemed like the hurricane season was slow. It was. We went through June and July with very little activity and it was not until mid-August that the reality of this season began to set in. Dean was a reminder of how powerful any hurricane can get, under the right conditions. Surely there would not be another cat-5 hurricane so soon- but now there is with Felix. In between, we had a deadly TS Erin which impacted Texas and a great deal of the eastern U.S. with flooding rains. The season is a reality now and that reality has potential for being quite harsh.

Felix is still a category five but indications are that it may be weakening some. The pressure is up since last night and the overall structure is not quite as pefect as we saw earlier. It won't matter much though, if Felix hits Honuras and/or Nicaragua and then on in to Central America, the flooding rains alone are lethal enough. The winds will die down quickly over land and will only add to the misery of the flooding. I sincerely hope that people can be evacuated from areas that are typically threatened by landslides but that may be wishful thinking. Felix is going to be a very bad hurricane for Central America. The threat to the U.S. is for all intents and purposes gone. It looks like Felix will track very far to the south and could even get lost in the land mass of Central America- who knows- it might just pop out the other side in to the east Pacific. We won't even go there yet, but it is a remote possibility.

Off the Southeast Coast, we are watching a slowly developing system that most computer models develop in to some degree of storm. This really is going to be a wait and see situation as the process takes time and the broad area of low pressure is not going anywhere fast. Those of us here in the Carolinas, I would keep an eye on this during the week. Some infamous hurricanes have formed from old frontal boundaries over the years (Diana in 1984, Bob in 1991 as just a couple of examples). You never know- the water is very warm off the Southeast coast.

In the far eastern Atlantic, we will be watching for the potential development of another tropical depression later this week. Almost all of the long range models develop something out there and track it westward over the open Atlantic. This is to be expected as the so-called Cape Verde season is in full gear now. We will have plenty of time to watch what ever forms.

From one of my favorite websites, Hurricanetracker.com

There are still no named storms anywhere on the planet and while this is remarkable, it will not last long. The bursts of activity come in just that- bursts. 2005 was an exceptional year where every few days we had a new named storm. That won't happen again this year (it better not) but we are about to ramp things back up again. The tropical waves over Africa are getting vigorous with deeper convection associated with them. Most long range models show more development off of Africa within a week. We will also have to look closer to the west Atlantic in the coming days as well as this time of year so-called "home grown" development can take place. Have no fear- the tropics are very quiet today and will remain so this weekend. I think we might squeek out another 5 to 7 days without any real problems brewing, but after that period, things should be quite busy once again.

During this stretch of hot weather, I thought it would be fun to get people to report what the high temperature for the day is in your own backyard. If you have a thermometer, go ahead and list your location and the high temperature from your backyard and any other information that you would like. (Time of day, any rainfall, etc...)

 

I'll start with yesterday's report:

 

Burlington, approx 3 miles NE of Burlington Airport:

 

Monday, August 6

 

99.1 degrees, recorded at 4:19pm

 

 

With the highs forecast to be in the mid-90's for the next several days, I want to start reporting the high temps recorded at my location to the TV meteorologists. Even though this is not "severe" weather, it is significant weather and a significant weather story. If you can use this information on-air that's totally up the people in charge of course.

The one thing I am unclear about is when reporting previously, I did not know who to send the e-mail to, since I do not know which person is scheduled to be on-air that evening. Is there a central place on this site for us to use to report this info, or should the Weather Watchers e-mail those reports Charles, Van and Emily all at once?

(ps) Thanks so much for the t-shirt. It's really nice and I may be submitting a new picture with me wearing it. I've been told that my current picture looks a little too "hairy".