Wednesday, May 28, 2008

More Ups & Downs May Bring Severe Weather by Friday


The atmosphere is certainly out of balance and everybody is asking for warmer weather after wind chills fell into the 30s in some places on Tuesday. The big theme today is to be careful of what you wish for. The good news is that all the kids on summer vacation can get back outside today and even blow some bubbles. The bad news is that we are long overdue for severe weather and here was the latest statement from the Storm Prediction Center as of late last night.

AS A SURFACE LOW MOVES ACROSS THE GREAT LAKES REGION DAY 4 IN CONJUNCTION WITH THE UPPER SHORT-WAVE FEATURES...A COLD FRONT WILL MOVE SEWD ACROSS MID MO/MID AND UPPER MS VALLEYS DURING THE DAY...AND INTO THE OH VALLEY REGION OVERNIGHT. WITH MOIST/UNSTABLE AIRMASS EXPECTED S OF THIS FRONT AND STRONG DEEP-LAYER WIND FIELD ACCOMPANYING THE SHORT-WAVE FEATURES /INCLUDING MID-LEVEL FLOW IN EXCESS OF 60 TO 70 KT/...WIDESPREAD SEVERE THREAT APPEARS LIKELY.


We are long overdue for severe weather. Here are your stats of the day and they are real eye-openers! In May of 2007 we recorded 18 storm damage reports, while in May of 2006 there were 27 reports of damaging winds, large hail, and tornadoes. This year we have had NONE. Here at home the earth has been shaking more from earthquakes and aftershocks than strong thunderstorms and this is very unusual. Here is the concern. The same extreme pattern that has caused a record tornado pace across the country along with the most tornado fatalities (110) in 10 years is still in place. How bad has it been. Well, the all-time tornado record of 1,817 set back in 2004 will be history in a few weeks if we keep this pace up. We have been very lucky to this point but this can change in a hurry. Here is why.


Unfortunately, the La Nina jet stream responsible for the wild weather continues to roar across the country and the concern by later this week is that it will not only move into Indiana to add spin to our thunderstorms, but it will have plenty of warm, tropical air to work with. So this is something we will have to watch very closely for the rest of the week and as we get closer I will fine-tune the timing for you. We have some ingredients coming together that we have not had so far this Spring which also includes a mix of both wind shear and instability. The latest lifted index for Lafayette by late Friday is now at -6. What does this mean. Check out the chart below.

Lifted Index:
+3 to +1: Slightly Unstable, chance of showers
+1 to -1: Unstable, expect showers and possibly an isolated thunderstorm
-1 to -3: Moderately Unstable, supports widespread thunderstorms
-3 to -6: Very unstable, widespread thunderstorms that may be severe
< -6: Extremely unstable, widespread severe weather

The CAPE values for Lafayette are running close to 2,100 j/kg. Here is what this means in human terms.

CAPE
500-1000 J/kg: Thunderstorms are possible
1000-2500 J/kg: Moderate thunderstorms, possibly severe
>2500 J/kg: Severe Thunderstorms likely

These numbers are only guides and should not be taken literally, just like our weather models.

Of course this could still change, but it is better for you to have a Plan B now rather than come up with one at the last minute on Friday. So now that we are aware of what can happen, we prepare for the worst just in case and hope for the best. Live Doppler 18 and Precision are ready to go. We will know more as we get closer and I will make sure to keep you updated on the upcoming crucial model runs.
At least for today we have some fine golfing weather for the NCAA Golf Championships being held at the Birck-Boilermaker Complex today through Saturday. Take a look at our virtual forecast for this afternoon. It is looking like nature is acing the forecast for all the golfers. Although if you are teeing off like UC-Irvine will be doing first thing this morning it will be a bit nippy with temperatures only in the 40s.

Our blog weather question today is dealing with the moon and why some folks have seen bright flashes on it, mainly with their telescopes. Were they seeing things or was it real? Is it the fighter jets again? I will have your answer coming up. Meanwhile, make it a great day!




2 comments:

Anonymous said...

Thanks for those explanations, Mike, on CAPE values and lifts.

We will wait and watch together!

Mary Anne in Remington

Anonymous said...

Recently, I just read about Flashes of light being seen on the moon. I believe the flashes of light are due to explosions caused by meteoroids hitting the moon. A typical blast is about as powerful as a few hundred pounds of TNT, and can be seen using a backyard telescope.

These explosions don't require oxygen or combustion. Meteoroids hit the moon with tremendous energy, traveling 30,000 mph or faster. "At that speed, even a pebble can blast a crater several feet wide. The impact heats up rocks and soil on the lunar surface hot enough to glow like molten lava--hence the flash."

Ray in Lafayette