Wednesday Afternoon Weather

Wednesday, July 25th 2007, 3:45 am

By: News On 6

A weak disturbance is dropping across central and eastern Kansas this afternoon and will approach northern OK later tonight. Iâ€™m a little concerned this feature may be able to generate a shower or storm that could float down near the area later. The upper air flow is still from the northeast but should change around Thursday. So far, I have not included any precipitation with this feature for northern OK. Travis will have another update later this afternoon.

Meanwhile moisture continues to slowly stream northward out of East TX and we could see a shower or storm forming in extreme southeastern OK or Northwestern Arkansas coincident with afternoon daytime heating. This probability also is very low.

No major changes will be made to the extended forecast at this point and weâ€™ll keep a slight chance of showers and storms basically from Friday late across the weekend. Probabilities will remain low for now. Latest computer guidance is supporting slightly higher coverage with the boundary Saturday into Sunday.

I have left the early morning discussion located below intact.

Alan Crone
KOTV

From this morning:
What a wonderful start regarding temperatures this morning! Some locations in eastern OK will be in the lower 60s. Most folks will be in the mid to upper 60s. This is really nice for late July! Highs today should be around 90 or so.

The weak boundary that has been near the area for the last few days is just about gone. Yesterday some scattered showers and storms formed just west of the boundary, but today with no real surface focus, only a stray storm would be likely. I'll not place a probability on the map today.

The wacky northeast flow is about to come to an end. What a strange pattern for July. The upper ridge has already shifted back to the southwest and now our air flows aloft will be arriving from the northwest sometime Thursday. This is still different for late July but something that we've seen for most of this summer. Another boundary will take a run at the area Friday night or Saturday and bring a chance of showers and storms to the area. Again, itâ€™s very hard to imagine a front making it south of the area, but we'll put the seat belt on and see what happens! I'll probably keep the winds from the southeast Saturday and knock a degree off the highs, but not much. Temperatures have remained well below average over the past few days and that will be the case for the next few days.
Latest computer data slowly moves the front southward into the area Saturday and Sunday. If this is true, the better coverage would end up around Sunday, and only around 30%. I have discounted this coverage and just kept a 20% probability for late Friday night after midnight, Saturday, and Sunday. Iâ€™ll be shocked if the front drops south of the I-40 corridor this weekend. But again, itâ€™s been a strange summer.

Record heat and wildfires continue across the intermountain regions of Utah, California, Nevada, Montana, and other states. A lack of significant snow pack earlier this year resulted in even less moisture during the spring thaw. Combined with dry fuels and drought conditions, major fires are underway. Some thunderstorms have occurred, but these storms have actually resulted in more fires. DRY THUNDERSTORMS are common in the west where clouds bases are very high and a layer of dry air resides under those bases. Any precip that manages to fall is usually evaporated before making it to the ground. This enhances the local wind flow at the surface. Additionally and more importantly, these thunderstorms do of course produce lightning which causes additional fires to form. Some additional fires in Utah over the past 3 weeks have been produced by lightning strikes from dry thunderstorms. Rain that falls and evaporates before reaching the ground is called virga. Virga has a thin and wispy appearance and is also many times accompanied by an increase in surface winds.

Enjoy the weather!

Alan Crone
KOTV