Monday, April 30, 2007

It's All Greek.........Omega Anyone?


This is a very interesting pattern we're dealing with. I have said this before, and I'll say it again, you'll need to locate the jetstream in order to come up with the forecast.


Right now we have a cutoff low that's developed over Texas. I have pointed that out on the diagram above. This low will slowly work our way, and provide the necessary lift for showers and storms over the next couple of days; moreover, if this low didn't exist, 850 mb temperatures would soar under the ridge, most likely creating record breaking temperatures all across the central and southern plains.


The position of the jetstream over the central plains is almost reminiscent of a typical summer like upper level pattern. The two lows that make up the omega block will help keep the ridge firmly in place. Both lows will deepen, creating a stronger and more pronounced ridge of high pressure by the end of the week, sending our temperatures into the 80s for the upcoming weekend!
I'm glad we have a cutoff low to save us from an early summer heat wave! We'll take the rain, welcome to May!

Posted by Drew Michaels at 8:25 PM 0 comments

WX GEEK HUMOR


Be careful what you do..., the Vorticity Owl may be spying on you!


~Hoo Hoo

Posted by Ted Zarras at 11:00 AM 0 comments

Sunday, April 29, 2007

PLANET C



So, we have found a planet 20.5 light years away from Earth that is within the “Goldilocks” belt of its parent sun, a region that is not too hot or too cold, it’s just right, to potentially support or sustain life as we know it. The planet orbits a red dwarf star named Gliese 581 and is formally known as Gliese 581 c, though astronomers have just been calling it Planet C.

First things first… how can we get there? Traveling at the speed of light or approximately 670616629.384 miles per hour, it will take us twenty and a half years en route, though Einstein proposed that anything having mass was incapable of traveling that fast… back to the drawing board. Even at a speed close to that of light, we’ve got some time on our hands. Checkers anyone? How about some sort of cosmic slingshot? There’s a saying that “laws are made to be broken”. Perhaps, like many discoveries, the mysteries of bending time and space will be un-locked while someone is trying to figure out something else totally unrelated. For now we'll assume that the getting there part isn't a big deal.

So, what would it be like? Temperatures are estimated to be in the range of 32 to 104 F and theoretically the planet has water. It sounds good so far. Planet C takes about two weeks to orbit the red dwarf and it may not be spinning on its axis. Well, one week of daytime and one week of night! Just think, your long day at work will be rewarded by a week of sleeping… again, doesn’t sound too shabby. I don’t suppose many Earth employers now would buy an “I was so tired and overworked that I had to sleep like I was on Planet C”, excuse. Oh well. Here’s another thought, celebrating your birthday might become passé, at one every fourteen days they would be coming quick. You might run out of gift ideas, and after awhile they would probably make a law against singing “Happy Birthday”. There’s a law that might not be broken, at least on Planet C. What is your age on Planet C? To find out, multiply your present age by 26 and there you go. I’d be over 1000!

Swiss scientist Michel Mayor, who heads up the European team that announced the discovery of Planet C, believes that top researchers are less than two decades away from being able to detect real signs of life in the solar system of Gliese 581. Perhaps, somewhere in time and space, someone else has figured out how to sling shot through the cosmos and is now finishing up a last game of checkers!






Posted by Ted Zarras at 4:59 PM 0 comments

Saturday, April 28, 2007

LITTER PREVENTION AND CONTROL

The facts below are taken from http://www.keeparkansasbeautiful.com/litter_prevention/

Facts about Littering


Arkansas has 100,000 acres of public roadside along its 16,367-mile state highway system, 9,700 miles of streams, and 600,000 acres of lakes … and, unfortunately, litter can be found along all of them!

It costs Arkansas more than $2 million annually to clean up along the highways, and $5 million in total cleanup costs. And even though littering is illegal in Arkansas - punishable by a fine and community service - litter continues to be a problem.

Common Forms of Litter in Arkansas:
Cigarette Filters
Plastic Foam
Food Wrappers and Containers
Paper
Glass
Plastic
Aluminum

Littering Effects - Litter Impacts Economic Development

Litter isn't just an environmental issue. It's also an economic development issue. When prospective businesses tour a community, they're looking for a dynamic, growing community where their businesses can grow. When communities have a lot of litter, it simply shows that the people living there don't care about their town's future. If they don't, new businesses won't, either.
This can hurt the economic development of a community. The absence of litter in a community reflects the pride that it shows and really does make a difference. Find out more about littering effects and how you can help
clean up your community.

Facts About Littering - How Litter Happens

It Gets Blown
Litter can blow out of a truck bed without the driver knowing.
Avoid putting anything in a truck bed that might blow out on the road.
Cover all loads to avoid items blowing out.

It Gets Thrown
Litter shouldn't be thrown from a vehicle.
Avoid throwing litter out of car windows by keeping a litterbag in the car at all times.
Request your free litterbag today!

It Gets Dumped
It is illegal to continue dumping your trash at the site where a dumpster once was.
These
illegal dumping sites can poison groundwater and kill local wildlife.
Don't create illegal dumping sites.

Reducing Litter

Reducing litter may be easier than you think! Here are three easy ways to reduce the amount of litter in your community:

Don't Litter! It's
illegal.
Report Littering.
Pick up Litter.

Additional Resources
Orang-U-Tongs
EZ Reacher

Looking for facts about recycling? Find out how Arkansas recycling can improve the success of the communities and businesses throughout the Natural State. Start recycling in Arkansas today!

Posted by Ted Zarras at 9:10 PM 0 comments

Friday, April 27, 2007

Helping the Environment by Planting a Tree

Today is Arbor Day, and with all of the talk about Global Warming and the overall destruction of the environment, I wanted to share some facts with you that will hopefully make you understand the importance of trees.

My goal is to help people realize that they really can make a difference by just simply changing some of their daily habits!

Trees make up an urban forest which works to:

1. Help reduce pollution in our air and water
2. Conserve utility costs and cool city streets
3. Reduce crime
4. Reduce asthma and improve our overall health and quality of life
5. Increase residential and commercial property values

Here are some very interesting statistics...

Around 500 full sized trees are needed to absorb the carbon dioxide produced by a typical car driven 20,000 miles per year.

One large tree can provide a day's worth of oxygen for up to 4 people.

One large tree can lift up to 100 gallons of water out of the ground and discharge it into the air in one day.

Researchers estimate that an urban tree can save 5 to 10 times more overall carbon dioxide than a rural tree.

If you have the opportunity, please plant a tree and help create a natural habitat in your own yard. Whether you live in the country, or the city, we can all do our part to help the environment.

Posted by Drew Michaels at 8:18 PM 0 comments

Wednesday, April 25, 2007

The Front is Coming Through.....

The severe weather is winding down. Strong storms continue to move across Newton, Pope, and Yell counties. These storms have the capability of producing strong gusty winds to 50 mph along with small hail.

As the sun goes down, these storms will quickly fall apart. A cold front will continue to sweep across eastern Oklahoma through 6 p.m. A few storms will remain possible along and north of I-40. through 7 p.m. No more severe weather is anticipated.

Posted by Drew Michaels at 3:32 PM 0 comments

1:45 PM UPDATE

Severe thunderstorm warnings have been issued for Craig and Nowata counties which border our north western area. Good breaks of sunshine have been developing off to the west and with a cold front still back near Tulsa; thunderstorms are likely through the late afternoon and into the early evening. A line of thunderstorms appears to be developing north to south, stretching through Muskogee and McAlester. We are watching this activity closely. The main threat with today's afternoon thunderstorms will be hail and gusty winds, though an isolated tornado can't be ruled out.

We'll be updating the blog throughout the afternoon and making cut-ins on-air as deemed necessary. Keep it tuned to 40/29... we've got you covered on-air and on the web!

Posted by Ted Zarras at 11:44 AM 0 comments

12:30 PM UPDATE


Northern counties; Delaware, Cherokee, and Adair in OK, along with Washington, Benton, Carroll, and Madison in AR, are now breaking out in sunshine. Cumulus clouds are beginning to pop as well. With the cold front still lagging back to our west the potential for thunderstorms, some of which may produce large hail, still exists. The wet bulb zero temperature is roughly at 8000 to 8500 feet. This is low and will certainly support large hail growth.

Individual thunderstorms are starting to pop between I-35 and I-44 in northern OK. The atmosphere has been capped this morning and into the early afternoon, though now this is starting to break. RUC analysis has a bull’s eye of 500-1000 J/kg of CAPE (Convective Available Potential Energy) over NW AR and NE OK. We are watching this area closely as a hot spot for thunderstorm development. The best window for storm development, coinciding well with sun breaks and peak heating. is now through the late afternoon as the cold front finally pushes through.

Posted by Ted Zarras at 10:37 AM 0 comments

Tuesday, April 24, 2007

RAIN REPORTS... so far

ARKANSAS

Mena 1.50"
Booneville 1.36”
Fort Smith 1.12”
Siloam Springs 0.97”
Fayetteville .93”
Springdale 0.75”
Bentonville 0.60”



OKLAHOMA

Talihina 2.26”
Poteau 2.21”
McAlester 1.86”
Westville 1.14”
Wilburton 1.16”
Cookson 1.09”
Sallisaw 0.91”



The heaviest thunderstorm activity right now is along a line which stretches from southeastern OK through Mena, Clarksville, and Harrison, AR. There have been severe thunderstorm warnings in association with this band, prompted by gusty winds along the leading edge. Heavy to moderate rain continues to fall across the River Valley as well as NW AR. We were down about two inches of rain as compared to monthly averages for April. With this event and additional rain tomorrow we may end up close to, or slightly above average for the month.

Posted by Ted Zarras at 6:57 PM 0 comments

8:30 P.M. Update

Showers and storms continue to move across portions of western Arkansas. Several severe storms were reported throughout Franklin, Johnson, Logan, Scott, and Polk counties. Heavy flooding rainfall may be an issue with some locations seeing localized street flooding. Never cross a street that is covered with water.

The severe threat continues to wind down across our viewing area. Lingering showers and some embedded storms will be possible through 9 p.m.

Posted by Drew Michaels at 5:27 PM 0 comments

6:00 P.M. Update

Strong to severe storms continue to push throughout eastern Oklahoma this evening. Look for those storms to contain small hail and gusty winds from 40 to 60 mph. There's still a tornado watch until 11:00 p.m.; however, the tornado threat is weakening as storms merge together in a general line.

The line of storms will move across the Oklahoma/Arkansas state line after 6 p.m. Rainfall could amount between .25" to 1.00" across the viewing area. Stay away from windows as the storms move over your town.

Posted by Drew Michaels at 3:31 PM 0 comments

3:30 PM SEVERE WEATHER UPDATE

An intense line of thunderstorms is racing across OK, and out ahead of the line there have been individual supercells. Numerous severe thunderstorm warnings along with tornado warnings have been issued in association with the line. Our entire area is under tornado watch, which carries through 10:00 PM this evening. The threat of damaging winds, large destructive hail as well as tornadoes will accompany this system as it continues moving towards the east. Individual storms will be traveling to the northeast at speeds of up to 40-50mph. The parent Low is centered over southeastern CO, as highlighted in radar imagery.

We are tracking individual cells in our western periphery and it is likely that over the next several hours we will have warnings, both tornado and thunderstorm, issued for some of our counties. We will be making all necessary cut-ins as deemed necessary. Right now the heaviest activity stretches from Bartlesville southward through McCalester and points south westward. Please have a severe weather plan ready.

Keep it tuned to 40/29… we’ve got you covered on-air and on the web.

Posted by Ted Zarras at 1:39 PM 0 comments

2:45 Weather Update

The dryline has become very active this afternoon, and storms are starting to fire in the moisture rich atmosphere ahead of the main line. Most of the storms are lined up along I-35 through OKC.

Expect showers and storms to intensify by 5 p.m. across eastern Oklahoma. Storms will move closer to western Arkansas by 7 p.m. tonight. Large hail and damaging winds remain the primary threats; however, there will be a strong tornado potential across SE OK tonight. EHI values have increased to 3.0, indicating strong low level wind shear.

We'll continue to update you throughout the afternoon.

Posted by Drew Michaels at 12:17 PM 0 comments

12:15 PM SEVERE WEATHER UPDATE

The dryline has now pushed into western OK, indicated by satellite imagery highlighting initial convection and thunderstorm development, along with surface dewpoint contours showing a bowing line of dry air pushing into the Clinton and Cordell area. A line of severe thunderstorms now stretches from Watonga and Lawton, OK through the Wichita Falls and Abilene area of TX. These storms mark the western periphery of Tornado Watch box #173, which encompasses our western area and expires at 8:00 PM.

We are still anticipating our western area to become active this early afternoon, with south and western counties having the threat of large hail, damaging winds and a few isolated tornadoes. This threat will be moving eastward throughout the day and as early as 6:00PM isolated severe thunderstorms along with line segments of severe storms will likely stretch through Jay, Tahlequah and Muskogee, OK to points southwestward. Benton, Washington, Crawford, Sebastian, Scott, Polk, Leflore and McCurtain counties will likely see the greatest threat of severe thunderstorms after 6:00 PM. Expect activity to be the most intense through the Midnight hour.


Be safe and be smart, which means being prepared! Have a severe weather plan ready. We are continuing to monitor developments. Keep it tuned to 40/29… we’ve got you covered on-air and on the web!

Posted by Ted Zarras at 10:15 AM 0 comments

Monday, April 23, 2007

Tuesday's Moderate Severe Weather Risk

The entire eastern Oklahoma and western Arkansas area remains under a moderate risk for severe weather for Tuesday evening. Our thinking remains the same. We'll have to wait for a strong 100+ knt jetstreak to move over the central plains by Tuesday afternoon in order for storms to fire. Storm initiation will likely occur along the dryline after 3 p.m. These storms will rapidly develop and move NE over 50 mph. We'll likely see storms after 5 p.m. across our area.

Dewpoint temperature, or the measure of low level moisture, will remain in the 60's throughout the warm sector on Tuesday. The air mass will be capable of supporting severe storms, so all of the necessary ingredients per our computer models will come together. Sunshine will be in question tomorrow, but it wouldn't surprise me to see peeks of sun throughout the day. Increased sunshine will only create more of a volatile and unstable atmosphere.

Make sure you have a severe weather plan in place. Please check back during the day on Tuesday for more blog updates..............

Posted by Drew Michaels at 8:18 PM 0 comments

MONDAY 1:00 PM SEVERE WEATHER THREAT UPDATE


After looking over some of the latest data, it’s still quite apparent that a significant severe weather event will unfold over the next few days. We’re starting to see partial breaks of sunshine to the south west and dewpoints are now in the low 60s across our entire area. As a general forecasting guideline, dewpoints above 55 are needed to sustain supercells.

As of the12Z observations, a broad trough of Low pressure is centered south of the four corners region of the US. Surface low development is occurring in the Albuquerque region of northern New Mexico with surface pressure now down to 1009mb. Air aloft at 700mb (10,000 ft.) is -4c, whereas the 700mb temp in Amarillo is 6c. *NOTE (see map above) Cold air filtering in from the North West, will continue to intensify the Low. This pool of cold air aloft will also destabilize the atmosphere and already, showers and thunderstorms are developing.

The 12Z run of the NAM has slowed down the forward movement of the Low, though the track is still to the east and over our area. The best dynamics appear to be coming together in the 6 PM to Midnight window of Tuesday. We will have a lot of jetstream energy aloft with winds blowing from the West South West as high as 130mph and a low level jet of 50mph blowing from the south. Surface winds look to be blowing from the South South East. This turning of height with the winds will aid in developing forward tilting and rotating thunderstorms, which are also known by the aforementioned name of supercells. The inflow of warm humid air into the thunderstorm rises, cools and condenses; then instead of falling back down into the storm, cutting off the fuel source, it gets blown to the front and back of the storm, allowing the thunderstorm to sustain itself for perhaps as long as a track as 200 miles. These storms will be moving at speeds of up 50mph to the north east. We will have the threat of seeing not only damaging winds and large hail, but tornadoes too. Please review your family’s severe weather plan and know what to do immediately if a Tornado warning is issued for your location.

Lastly, several embedded troughs, cycling around the low will provide the lift to initiate storm development. The dryline, which will be just to the west of OK City by tomorrow afternoon, will likely be a hot spot for storm initiation too. With the slower speed of the parent Low, it is likely that large storms on Tuesday, will transition into a batch of heavy rain with embedded lightning and thunder, lasting into the early morning hours of Wednesday. We’ll then be watching for redevelopment of storms by Wed. afternoon, which may last once again overnight, into the early morning hours of Thursday.

We will be making updates throughout this entire event. Keep it tuned to 40/29, we’ve got you covered on-air and on the web!

Posted by Ted Zarras at 10:30 AM 0 comments

Sunday, April 22, 2007

Tuesday's Severe Weather Update


I want to take this opportunity to add to what Ted wrote in his previous blog entry about this week's severe weather. Spring time is all about the location of the jetstream. The placement of the jet is crucial for severe weather development; moreover, our window of opportunity will be late Tuesday afternoon and evening for strong to severe storms.


Our next jetstreak is currently moving out of California toward the desert southwest. This tightly packed bundle of winds around 30,000 ft could be as strong as 130 knots. These types of winds will ultimately lead to strong upward vertical velocities, and explosive severe thunderstorm development. Look for the central Oklahoma dryline to provide the initial focus for storms by Tuesday afternoon.


Wind shear will be every high by Tuesday evening across SE OK and SW AR. Storm motion will be very fast, moving from the SW to NE. Storms that fire across SE OK will have the chance to move toward the River Valley. Large hail and isolated tornadoes can't be ruled out with the strongest storms. The best tornado threat at this point looks to be along and south of I-40. ***Please take a look at where the tornado threat exists in relation to the jetstreak.***


This would be a good time to review your severe weather safety plan with your family. It has been a few weeks since we've seen severe weather, so make sure everybody knows where to go when severe weather strikes. More updates to come!

Posted by Drew Michaels at 8:23 PM 0 comments

SEVERE WEATHER THREAT

The top half of the week will be quite active as a powerful storm system passes through our area. We’ve had a southerly wind for several days, due to an area of High pressure parked to our east. The wind has been blowing over the Gulf of Mexico; subsequently, lots of moisture has now been transported into our area. In fact, today actually felt a little humid! This moisture is a precursor and important ingredient to a set-up for thunderstorms.

The storm system is pulling in a relatively cold air mass aloft and this will make the atmosphere unstable. Daytime heating coupled with a frontal boundary will provide the lift to fire off convection and due to the turning of the windfield with height; it is likely that rotating supercells will develop. Our threat will mainly be for large hail and gusty winds though there is chance of tornados too. The storm system will likely push through early on Wednesday and there afterwards, we should get break for a few days. We’re monitoring developments closely… keep it tuned to 40/29 on-air and on the web, we’ll keep you advised!

Posted by Ted Zarras at 4:03 PM 0 comments

Saturday, April 21, 2007

SEVERE THUNDERSTORMS ERUPT OFF THE DRYLINE


As the day progressed, ingredients mixed together nicely to kick off a large batch of storms to our west. By early afternoon, much of western Kansas, Oklahoma and Texas were nearing CT or Convective Temperature. Convection is a word for rising motion and CT is just the temperature at which air will rise unimpeded by a surrounding colder environment. Think of a bar of ivory soap brought down to the deep end of swimming pool. When let go the soap goes shooting to the top. In this case air goes shooting to the top of troposphere, where the temperature of the atmosphere warms. The air will rise until it is cooler than its surrounding environment. This is the general concept of stability, or in today’s case, instability. The atmosphere was very unstable. Storms fired off of the dry line, where air of different densities and very different moisture content meet. It is often the first place storms will develop. To the east dewpoints were in the upper 50s and to the west of it, values were in the mid 30s. The wind profile, associated with an impressive upper level storm system, helped churn the atmosphere up, and like clockwork around the hottest time of the day, the storms went off! Thus far, there have been 12 reports of Tornados.

Presently, single cell thunderstorm activity is melding together into a batch of thunderstorms that is linear in nature. Such features are capable of and indicative of damaging winds, especially if the line begins to bow. The tornado threat is lessening, though south of the batch of thunderstorms, there still is the possibility of single cells forming. This cluster is sending clouds as far east as Oklahoma City and precipitation extends to Clinton, OK which is about 85 miles to Ok City’s west. General movement with this storm system is too the North Northeast. We may get a lingering shower or thunderstorm early, though the activity will have significantly lessened at that point. There may be an outflow barrier or two lingering over our north western area that may provide a focus for a few thunderstorms tomorrow afternoon.

Posted by Ted Zarras at 9:45 PM 0 comments

Friday, April 20, 2007

Dry Line Storms for Saturday?


We're watching a shortwave trough toward the southwest that looks to ignite storms along the dryline by Saturday evening. Dynamically speaking, the trough looks to become negatively tilted after sundown, but will those storms move off the dryline and into our area by Sunday morning? A negatively tilted trough is significant because of the enhanced upward vertical motion it provides. These types of upper level features commonly produce severe weather. I have included a model depiction of a negatively tilted trough above.


The 0Z run of the WRF shows a specific dryline to set up across western Oklahoma, and with decent surface heating creating CAPE values over 2,000, those storms will erupt as the cold pool aloft cracks the cap. Overall shear is not very favorable for a large number of tornadoes, but significant surface heating and strong updrafts would support large hail and damaging winds.


Storm motion will likely be to the northeast, so chances for our area seeing storms is only running around 20%. The models are trying to indicate an MCS to move across central Oklahoma, so extreme eastern Oklahoma would be the most likely area for decaying storms for Sunday morning. We'll keep an eye out on any thunderstorm potential.

Posted by Drew Michaels at 7:58 PM 0 comments

NASA, NOAA Data Indicate Ozone Layer is Recovering


A new study finds consistent evidence that the Earth’s ozone layer is on the mend. The study was conducted by a team of scientists from the Georgia Institute of technology and led by Dr. Eun-Su Yang. The study compared observations with model data throughout all levels of the Stratosphere.

The Stratosphere, the Earth’s second lowest atmospheric layer, which lies between10 and 50 kilometers (6 and 31 miles) above the surface, contains 90 percent of all atmospheric ozone. Ozone filters out harmful UV rays from the sun. Ozone declined steadily from 1979 through1997, correlating well with a peak production of ozone-destroying gases such as chlorofluorocarbons or CFC’s. CFC’s were phased out after the 1987 international Montreal Protocol was enacted.

To measure ozone at different layers in the atmosphere Dr. Yang’s team used data from balloons, along with independent ground-based observing networks, as well as monthly averaged satellite data which came from five independent NASA and NOAA instruments. The measurements were compared to computer predictions of ozone recovery that factored in variations in human produced ozone destroying chemicals.

Results of the study confirm that the Stratosphere is no longer being depleted of ozone and that levels could be restored to those of 1980, by sometime in the middle of the century.

Posted by Ted Zarras at 8:19 AM 0 comments

Thursday, April 19, 2007

A Warm March, A Cool April… So Far

We ended up eight degrees above monthly averages for the month of March, temperature-wise in both Fayetteville and Fort Smith. Conversely, April has been cool so far with temps running about 6 to 8 degrees below average, though over the past few days we have been at average our slightly above.

Rainfall-wise, we’ll need a few more decent events to bring us up to par, though we’re not terribly dry right now. By next week, a trough which is now digging out in the Pacific south of the Aleutians is slated to track across the mid-south and central plains. This will likely bring both our next shot of significant rain and potential severe weather to the area.

Posted by Ted Zarras at 11:17 AM 0 comments

Wednesday, April 18, 2007

Scattered, Isolated, or Likely??????

The warm summer months are right around the corner, and you know that means more familiar terminology from your friendly 40/29 meteorologist. These definitions are straight from the National Weather Service criteria.

Isolated = Less than a 30% chance for storms to occur in a given a location.

Scattered = 30% to 50% chance for storms to occur in a given location.

Likely = Greater than a 60% chance that storms will occur in a given location.

Posted by Drew Michaels at 8:17 PM 0 comments

Gusts to 156 mph!




Gusts up to 156 mph and winds equivalent to a category 5 hurricane blasted the top of Mount Washington, NH in the recent powerful Nor'easter. While not common, this is the second time in the past year and only the third time in the past ten years that winds have reached this velocity. Sustained winds, blowing in from the east were over 120 mph for many hours.

Weather Observers had a tough time keeping instruments clear of ice and debris because of the force of the winds against the observatory doors. Check out the force of the winds in this link.
http://www.youtube.com/watch?v=lmQw-MF62BU

The Mount Washington Observatory, which began recording meteorological observations in 1870, recently celebrated the anniversary of their world record recorded wind gust on April 12 (April 12, 1934 gust at 231 mph!).

Posted by Ted Zarras at 8:26 AM 0 comments

Tuesday, April 17, 2007

Tuesday Evening Weather Update

We're continuing to watch scattered showers and a few embedded thunderstorms move out of central Oklahoma toward our area. No severe weather is anticipated, but some of the stronger cells may contain small pea size hail, especially as the cold core low moves overhead after sundown. We're still expecting between a .25" to 1.00" of rain across the viewing area. Heavier rainfall looks to move in after 10 p.m.

As the low departs to our east on Wednesday, we'll expect subsidence on the back side of the system to create afternoon sunshine. Look for highs in the mid to upper 60s and lower 70s. Warmer temperatures will return toward the end of the week! Enjoy the rain......

Posted by Drew Michaels at 4:38 PM 0 comments

Monday, April 16, 2007

More Rain for Tuesday....Hail Producing Storms?


A similar southbound moving storm storm system is heading our way for Tuesday afternoon and evening. Right now we're watching this storm move out of the 4-corners region of the southwest. Dewpoints are pretty low today, which helped temperatures warm quickly this afternoon into the 70s; however, moisture will be increasing overnight, as a surface high slides southeast toward the gulf.


Our computer model guidance has our area receiving between 0.25" to 1.0" of rainfall. Some spots could see some locally higher amounts under some of the stronger thunderstorms. The heavy rainfall will likely happen toward sundown on Tuesday evening.


These types of low pressure areas have a lot of cold air aloft, so small hail will be a threat for everybody. I have included a model depiction of the cold air aloft around 10,000 ft, so you can visually understand what I'm referring to.


There is a severe weather threat for extreme southeastern Oklahoma and southwestern Arkansas, but much like last week, most of the severe weather will be contained across Texas. Stay tuned for more updates.

Posted by Drew Michaels at 4:04 PM 0 comments

Sunday, April 15, 2007

VENUS…Looking Good!


One of our regular weather trackers out in Wister, OK called tonight wondering what the bright object in the western sky was. A quick guess from both of us was that perhaps it was Jupiter, though I told him that I would check it out. Well, it turned out to be VENUS! In fact, a lot of people have been taking notice of Venus. Some have even thought they were seeing a UFO!

We should have good viewing conditions again tomorrow so here’s where to look. Venus will be about 40 degrees north of the western horizon at sunset and will continually lower in the western sky until it sets around 11:00 PM. On the 19th, this Thursday, a thin crescent moon will add to the beauty of the second planet from the Sun, sitting just a few degrees lower and to the right in the sky.

Posted by Ted Zarras at 8:52 PM 1 comments

Saturday, April 14, 2007

One more cold night!

The system that brought better than an inch and a half of rain to a few lucky locations and a solid half inch to an inch plus in others on Friday has pushed off to the north east. Wrap around clouds and precipitation across NW AR and NE OK and some chilly air aloft kept temps today some 25 degrees below seasonal average highs! This will not be the case for Sunday, but we do have to contend with one more cold night as a few northern locations settle mighty close to the freezing mark by tomorrow morning.

We’ve been monitoring a clearing trend which has been slow but steady. Fort Smith and the River Valley saw late day breaks of sun give way to a mostly clear sky, though areas to the north still had the clouds to contend with. A few fast moving showers dropping into our area from Kansas may stick together long enough tonight to bring a little drizzle and or a flurry to northern locations overnight. But, tomorrow afternoon will be feeling a bit more spring-like with ample sunshine and much warmer temps.

Posted by Ted Zarras at 9:04 PM 0 comments

Friday, April 13, 2007

Severe Weather Threat is Over

The showers and storms that raced our way across central Oklahoma have finally hit the wall. The atmosphere across eastern Oklahoma has cooled and become stable.

Most of the strong thunderstorms have weakened, but some cells may produce small pea size hail. The heavy rain will transition after midnight to light rain and drizzle. Snow will be a factor if you're heading north along 71 to Kansas City tonight. Extreme northeastern Oklahoma may see some snow mixing with rain by Saturday morning, but no major accumulations are expected across our viewing area.

Posted by Drew Michaels at 8:24 PM 0 comments

EVENING SEVERE WEATHER THREAT

The Storm Prediction Center has extended a watch box to encompass many of our southern counties in AR. This latest watch is active through 2:00 AM. This includes Sebastian, Logan Scott and Polk counties. The northern boundary is very close to I-40. Many of our Oklahoma counties still remain under a severe thunderstorm watch too.

An intense line of storms has been racing across Texas and Oklahoma, where breaks of sunshine and very moisture rich air have fueled super cells. Although the motion of the upper level Low continues to be to the east, this line of storms may rotate through our southern area tonight. The main threat will be gusty winds and large hail, though an isolated tornado across extreme southern counties near the OK / TX border can’t be ruled out. Expect the heaviest precipitation to fall through the 10:00 PM to 3:00 AM window.

Posted by Ted Zarras at 4:47 PM 0 comments

Severe Storms South...5:00 Update

Good news, the tornado threat continues to remain south across Texas this afternoon. As we anticipated, the warm front has not moved very far north, keeping the real juicy air out of our reach. Shear and moisture convergence are very impressive this afternoon ahead of the dry line, and that's where the nasty weather is contained.

This evening more scattered showers and storms will some locally heavy rainfall will move north ahead of the upper level storm. Some of the stronger storms may contain small hail, but no major severe weather is anticipated. We'll have more updates to come!

Posted by Drew Michaels at 2:08 PM 0 comments

1:45 PM Update


We’ve received reports, as well as the above picture taken 3 mi. west of Hon, Ar, of small hail that fell in some stronger thunderstorms that pushed through this morning and early afternoon. The storms we’re kicked up by a wave of low pressure that has now moved into southern MO.

RAIN REPORTS

Here are the totals so far.

Fort Smith 0.20”
Fayetteville 0.22”
Poteau 0.38”
Sallisaw 0.59”
Springdale 0.22”


We’ll continue to see bands of moderate to heavy rain push up into our area from the south west, though we are north of the warm front and in a more stable environment. Consequently, we look to remain cool, rainy and overcast throughout the rest of the day.

Posted by Ted Zarras at 11:22 AM 0 comments

11:45 AM Update:

Heavy rain showers with some imbedded pea size hail have pushed into the River Valley area. A cell, capable of producing nickel to quarter size hail is moving into SW Logan County. This storm looks to continue on a north easterly track and will likely pass near or through Booneville, Paris and Clarksville over the next hour.

As a leading wave of low pressure, cycling around the main area of Low pressure to our west, continues to push through over the next several hours, expect a transition to more of a heavy rain event with embedded lightning and thunder. Temperatures will stay cool today with the threat of severe weather holding to our south.

Posted by Ted Zarras at 9:33 AM 0 comments

Thursday, April 12, 2007

Close Call for Severe Weather


Position and timing is everything when it comes to severe weather. What looked like a potentially dangerous severe weather day, may now actually turn out to be more of a heavy rain event. No complaints here, bring on the rain! Now, with that being said, we're still going to watch Friday closely.


The warm front is forecast to basically hang over the Red River, keeping the real deep moisture and warmth to our south. If the warm front moves further north than expected, then SE OK and SW AR will end up being in a moderate risk for severe storms. The warm front will provide the tornado focus by Friday afternoon and evening, so my thought is that north Texas and Louisiana will be targeted.


The dynamics to this system remain very impressive. The turning of winds with height known as "wind shear" is off the charts, especially along the warm front. Deep moisture convergence, and a screaming jet streak make a severe weather outbreak likely, but not here.


For us, we'll be north of the warm front, which means steady rain and embedded storms. The winds will be howling from the east, with temperatures only climbing into the 50s. We can expect anywhere from .50" of rain to 1.50" by Saturday morning. We desperately need a surplus of rain before we get into the summer months.

Posted by Drew Michaels at 2:31 PM 0 comments

Wednesday, April 11, 2007

Winds of Change....Friday's Severe Weather?

You could definitely feel the winds of change in the air on Wednesday. Winds gusted over 40 mph in many locations, downing trees in saturated soils, as a tight pressure gradient engulfed the area. That same system was also responsible for heavy snowfall across portions of the Midwest. Welcome to April! As we say goodbye to our last weather maker, we watch another one coming our way for Friday.

This next storm could turn out to be more of a rain maker than a severe weather maker across eastern Oklahoma and western Arkansas; however, we're keeping our eyes on SE OK and SW AR for a significant severe weather threat. Why will only our southern counties see the chance for significant storms? The answer lies in the position of the warm front.

Typically, a trough will start to lift as it moves east out of the southwest of the U.S., racing a surface low to the northeast. Our area tends to become warm sectored, and if enough instability exists, we'll rapidly develop severe weather. The Friday storm looks different. Instead of lifting, the trough is forecast to dig, creating a surface low that will ride east along the Red River. We're expecting the warm front to set up somewhere across SE OK and SW AR, which is pretty far south.

The warm front is a very interesting place to be during the spring. North of the front will typically experience embedded storms and heavy rainfall; however, along the boundary itself, extreme turning of the winds will occur, creating a favorable environment for tornadoes. Storms that form along the warm front will have the potential to rotate and produce tornadoes. Think of all the winds spiraling into the surface low. It will be a heavily sheared environment.

The key on Friday will be to locate the actual position of the front, and determine just how far north it will go. I have noticed the NAM likes to advect the front too far north, but my gut says the warm front will stay south of the River Valley. Temperatures across NW AR may only be in the 50s on Friday! We'll continue to update you on this developing storm system.

Posted by Drew Michaels at 9:29 PM 0 comments

Monday, April 09, 2007

FAIR WEATHER FUNNEL


It all started with an email we received on Saturday April 7th; a tornado had been sighted. High pressure was in control and the closest thunderstorms were several hundred miles away, so what could it have been?

After a pleasant email exchange and a great description of the event, it was absolutely apparent that indeed something happened around 10:50 am that Saturday morning in Benton county. It was time to do some atmospheric investigating. Satellite imagery confirmed that we just had a few high clouds in place but shape-wise they were indicative of a strong jet stream. Archived upper air maps for Saturday, showed that not only were winds aloft in excess of 100 kts., but due to the positioning of the jet stream, NW AR was in a sweet spot for upper level divergence, inferring rising-motion at the surface.

On Saturday morning we tied records and temps were still in the upper 20s at the time the funnels were observed. With good breaks of sun earlier in the morning it is likely that strong heating of the ground, perhaps over a recently plowed field, set a "blob" of air rising. On a micro scale the atmosphere was very unstable with this warm pocket sitting below and being surrounded by cold air. A little eddy of spinning air, possibly originating from something as simple as a breeze blowing around a barn, hit that rising blob. At this point a process known as vortex stretching took place. As the spin rose and became elongated, due to the conservation of angular momentum, the speed of the funnel increased. As the rising air condensed and perhaps some dust and debris became suspended, it became visible.
We were told that the main funnel lasted for over ten minutes and that a secondary one eventually intersected with the main. The picture above, which was toned down to better highlight the funnels was captured as part of this meeting took place. Shortly there-after, the funnels dissipated.
A big THANKS goes out to the fine folks who shared this neat meteorological occurrence with us.
Perhaps there were other viewers of this awesome sight too.

Posted by Ted Zarras at 8:09 PM 0 comments

How to care for damaged plants and trees

I have good news to report, even after this nasty cold snap, many of the damaged trees and plants should make a decent recovery. I talked with Donna at the Fort Smith Garden Center, and she says that we should see more growth when the weather turns warmer. Here are some important tips she says you should follow in order for your foliage to make a healthy comeback.

1. Don't prune or cut back the plants or trees. Allow the leaves or buds to fall off naturally. When the warm weather returns, they will likely bloom again.

2. Don't feed the plants with plant food or fertilizer. This will damage the plants. Allow them to naturally return.

Posted by Drew Michaels at 7:17 PM 0 comments

Sunday, April 08, 2007

TWO TIES TWO RECORDS

So, if you were out and about pretty much anytime over the weekend, we don’t have to mention that it was cold! But, let’s quantify what cold meant the past two mornings.

Just below this post were the records in jeopardy over the weekend and like the title of this entry states, we tied two and left two in the dust!

Saturday’s Lows: TWO TIES

Fort Smith: 29F
Fayetteville: 24F

Sunday’s Lows: TWO RECORDS !

Fort Smith: 24F
Fayetteville: 17F

The week ahead is looking very spring like with several chances for rain. Tuesday into Wednesday is chance number one. This system does not look to bring in severe weather, though a system late in the week will be coming in with a hefty jet. This is chance number two and the ingredients may come together for a batch of strong thunderstorms. Our long range pattern is looking to become more active too, with perhaps another impressive system for next Monday / Tuesday.

Posted by Ted Zarras at 9:00 PM 0 comments

Friday, April 06, 2007

IMPENDING RECORD LOWS!

Present Records:

Fort Smith, AR

April 7, 29F 1990
April 8, 33F 1971

Fayetteville, AR

April 7, 24F 1971
April 8, 27F 1956

We’re likely to bust all four of the above records over the next few days as cold air continues to flow southward. Tonight, there is a freeze warning that goes just about all of the way to the Gulf of Mexico! Sunday will likely be the lower of the next few mornings, with many locations dropping into the teens in NW AR and NE OK.

*March was about ten degrees above average for the month, so we shall see how we end up for the month of April.

Posted by Ted Zarras at 4:02 PM 0 comments

Thursday, April 05, 2007

Let it Snow, Let it Snow.....


Well, back by popular demand, northwest Arkansas and northeastern Oklahoma saw the snow come down on Thursday night. We have talked about the snow over the last couple of days, and I was glad to see some winter like pictures!


A fast moving shortwave kicked off the snow in Kansas, which quickly spread across Missouri and Arklahoma. Temperatures aloft were able to support the snow, but at least the ground temperatures were warm enough to keep snow from accumulating on the roads; however, grassy surfaces and cars were able to accumulate snow. Many spots in Benton and Carroll counties saw between a dusting to an inch.


Chilly temperatures will be with us through the Easter weekend before warmer temperatures return by early next week.

Posted by Drew Michaels at 8:19 PM 0 comments

Tuesday, April 03, 2007

Flurries Return to the Forecast......


I know, I know, it's hard to believe that we're talking about a chance for flurries after temperatures have been in the 80s. That's almost as realistic as me taking over the U of A basketball program, well, anything is possible.


Here's the setup. We're going into a pattern where our forecast will be dominated by a northwest flow regime. What does that mean from a forecasting perspective? The winds from 5,000 feet all the way up to 30,000 ft will be out of the northwest. I have included a picture to show you what this pattern looks like. We'll see reinforcing shots of cold air coming our way, especially into Friday morning. Several disturbances within the northwest flow could provide the lift for precipitation to develop if the moisture is present.
Moisture at the 700 mb level will be riding along the northwest flow, and according to the oZ WRF model, temperatures aloft would support snow flurries north of I-40. We're expecting surface temperatures in the 30s for Friday morning.


Typically, when we cold air advect, we'll see cold air stratocumulus develop across the area. If a little disturbance aloft can create some precipitation, it will fall as snow flurries if the atmosphere is cold enough. The 0 degree isotherm at 850 mb cuts across northwest Arkansas, so this will be a close one.

Posted by Drew Michaels at 8:04 PM 0 comments

Winter like Highs & Lows Return

Over the next several days a blocking pattern will develop with a Low over the Pacific, a ridge of High pressure just to our west, and an impressive Low over Hudson’s bay in Canada. This set-up as we’ve discussed on the weather blog before is known as an Omega Block; typically weather becomes somewhat stagnant within this feature and depending on position within, the same type of conditions can persist for days. With that being said, the Jet stream will be parked in place just to our west, keeping us in a cool northwesterly flow regime. Another boundary looks to pass through on Thursday, ushering in even colder air aloft. So, a period of seasonably cool weather is looking imminent.

So, just how cold might we get? Climatological averages for this week are around 71/45 High/Low in Fort Smith and 65/43 in Fayetteville. Over the next several days Fort Smith will be averaging highs in the mid and upper 50s with lows in the mid and lower 30s. Fayetteville’s highs may not break 50 for a few days and lows will likely be dipping below the freezing mark. These numbers are more indicative of early and mid February! Sensitive plants may need to be brought indoors for a few nights.

FYI: Frosts are possible in the River Valley through mid-April and in Fayetteville through mid-May.

Posted by Ted Zarras at 4:19 PM 0 comments

Monday, April 02, 2007

Cooler Changes Are Coming........

We're watching a pretty stout cold front to our north which looks to bring a chance for some showers and storms on Tuesday, and some cooler changes to our weather. Temperatures this time of the year should be in the upper 60s and lower 70s, but over the past week, we've been enjoying above average highs; however, after this front passes through, we'll experience below average temperatures all the way into the Easter weekend.

Let's talk about storm chances for Tuesday. Look for a pretty substantial cap aloft to exist in our atmosphere from all of the warm air advection, with that being said, we'll need a lot of surface heating ahead of the front to lift the air mass. The best chance for this to occur will remain south of I-40. This area will have the greatest potential for maximized surface heating before the frontal passage. If the cap can be broken, look for CAPE values to exceed 2,000, which could result in large hail. Storms won't be sticking around though, so if you're lucky, you could see some brief heavy rain before the front clears your area. Rain chances from north to south are only running around 30%-40%.

Aloft, we'll see a blocking pattern set up toward the end of the week, which will allow an area of low pressure to deepen across the northeast. This dominant low will send reinforcing shots of colder air our way throughout the weekend. More to come on the colder weather!

Posted by Drew Michaels at 8:07 PM 0 comments

Sunday, April 01, 2007

THE WEEK AHEAD...

The week ahead is filled with a little of everything. We’ll start off on the warm side cresting better than 85 degrees in many locations on Monday, but, by Tuesday a fair amount of moisture looks to make it back into the area on south southwesterly winds setting the stage for the possibility of some strong afternoon thunderstorms as a cold front passes through.

On the severe weather note and threat for Tuesday, forecasted cape values are high and dewpoints are better than 60 in the River Valley. The cold front will provide the necessary lift. Timing will be key and just how much sunshine we receive will largely dictate the severity of the storms. Hail, gusty winds will be the primary threat, though an isolated tornado can’t be ruled out. We’ll cool down quite substantially after this, with several days of temps slightly below seasonal averages.

A secondary shot of cold air looks to slide in on northwesterly flow for Thursday. At this point it does not appear to have a great amount of moisture with it, though temps look to flirt around the freezing mark in northern locations come Friday and Saturday morning. Make sure to protect those sensitive plants.

Have a great week!

Posted by Ted Zarras at 9:38 PM 0 comments