Archive for September, 2007

TWO SYSTEMS
September 30, 2007

Two troughs of low pressure mark our weather over the next several days. The first is just off to our north north west. With most of the jet energy to our north, the threat of severe weather looks to remain low , though a strong storm may pop across northern locations late in the day on Sunday. System number two is just pushing into the pacific northwest and again, this looks to go just to our north, though moisture will be funneling into our area with a predominant southerly wind; so, some shower and thunderstorm activity is likely as it passes through around the Tues. / Wed. time frame.

The jetstream goes somewhat flat there afterwards and remains to our north. We may have a week plus wait until the next substantial cool down.
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Speed of Sound
September 29, 2007

Speed of Sound

The speed of sound is roughly 769 mph or 1128 ft. per second.

One mile equals 5, 280 feet.

Sound travels 5,680 feet in 5 seconds. So, this distance is just over one mile.

This information comes in handy when figuring how far away a bolt of lightning is. By counting the seconds of silence between lightning and thunder and dividing by five you will be able to approximate how far away the bolt was. For example: If you can count to ten after a bolt of lightning strikes before hearing the thunder, that bolt was about 2 miles away.

Interesting things happen as an object approaches the speed of sound, specifically with airplanes. Waves of sound become compressed in relation to the nose. Depending on the content of water vapor in the air, a variety of cone shaped condensation clouds can appear very close to the moment that the speed of sound is exceeded. For more information about this phenomena try searching “Prandtl-Glauert singularity”.

The Jetstream’s Getting Active
September 28, 2007

Welcome to the fall. The sun angle is quickly decreasing, and cold air is really starting to pool to our north. With all of that said, we’re talking about an active jetstream, and that’s a sure sign of the fall. season The jetstream’s strongest winds occur during the winter; however, they do start increasing throughout the fall, and that can spell severe weather outbreaks.

Severe weather may be an issue to our north this weekend. Look at the jetsream to our north. Divergence aloft will mean rapid lift for showers and storms throughout the upper Midwest. We call this a negatively tilted trough, which is very indicative of severe weather when moisture is present.

With most of the dynamics to our north, we’ll only see a slight chance for showers and storms on Sunday.

Cold Front In The Northwest…
September 27, 2007

A cold front moving into the Pacific Northwest will be creating showers along the coast. Behind this front is much colder air which will begin to cool the Pacific Northwest over the next 36 hours. Highs look to only be in the upper 50s for Seattle, Washington today. This front could skim the area on Sunday giving us a slight chance for showers. We will continue to follow this system very closely and will keep you updated on whether it will effect your weekend plans.

Wednesday’s Rainfall
September 26, 2007

Another disturbance aloft ignited more showers and storms across the area today. Rain and storms moved across eastern Oklahoma and western Arkansas leaving some spots under an inch of water. All in all September has been a wet month in many spots, but it looks like we’ll finish out the month with dry weather.

FALL SEASON OUTLOOK
September 26, 2007

Here is the latest Fall Outlook for the United States from the Climate Prediction Center. This is a great tool to get a feel of what we could be seeing in the months ahead when it comes to precipitation and temperatures. We look to be right on par for where we should be with our Fall Season precipitation totals, but notice the prediction for the temperatures. The Above Average contour is located in Eastern Oklahoma and Western Arkansas. So if this prediction is accurate we are looking at normal precipitation and above average temperatures for the next 3 months. It’s a whole new way to look at Autumn!

Tropical Storm Lorenzo?
September 26, 2007


Tropical Depression #13 is taking currently spinning in the Gulf of Mexico. This system looks to take on Tropical Storm characteristics later today or early Thursday morning. Weather models don’t really know what to do with this depression, but it looks like it could send some moisture into Southern Texas over the weekend.

The Latest On Tropical Storm Karen
September 26, 2007

Tropical Storm Karen is located about 1285 miles East of the Windward Islands. She is moving West at 14 mph and is showing a gradual turn to the West-Northwest over the next 24 hours. Karen’s maximum sustained winds are 50 mph with even higher wind gusts. She should begin to strengthen in the next 24 hours and she could become a hurricane by Thursday afternoon.

Tuesday Afternoon Update
September 25, 2007

The leading edge of the bright clouds draped across NWA, which stretch back to the southwest across eastern OK mark a line of strong thunderstorms which are firing off along a front just to our west. These storms could be packing wind gusts as high as 50 mph along with small hail. Please monitor developments using our looping SuperDoppler radar. You may want to adjust a trip to the grocery store or mall accordingly.

Keep it tuned to 40/29, we’ve got you covered on-air and on-line!

Moisture Transport…..Fueling Storms
September 25, 2007

A large area of high pressure continues to dominate the east coast. Winds around this high are ushering in southerly winds straight off the gulf of Mexico right into our area. Over the last couple of days we’ve seen southerly winds pumping dewpoints back in the 60’s throughout eastern Oklahoma and western Arkansas.

This type of airmass is more reminiscent of spring, and it could fuel showers and storms Tuesday afternoon and evening. A cold front will provide the lift for the showers and storms. The severe threat should remain low. Limited wind shear and warmer temperatures aloft will suppress large hail; however, sunshine is present, look for the chance for small hail and gusty winds with the stronger storms.