Severe Storms Next Week?

Right now, WFAA has mentioned a possibility of showers & thunderstorms late next week into early next weekend. The question on everyone's mind is, will we see storms out of this disturbance? Well, usually these disturbances have been known to "peel" away the cap in order to induce forcing (how the thunderstorms punch through.) I am going to post a series of Upper Air Soundings showing the difference in the soundings to tell whether there is a cap or no cap. (Measure of the Earth's Atmosphere)

Sounding Examples

GFS Sounding from Lubbock, Texas (3/19/2011 at 04z (11:00 pm))

This sounding shows 4 lines. Focus on the main red one which is the actual temperature. As you can see, the line is going up at a steep angle and is not curved. This means there is not a capping inversion in the atmosphere. There was a severe weather situation occuring in Lubbock due to this no capped atmosphere. Plus there was a dryline and stationary front to fuel it all.

GFS Sounding of Decatur, Texas (3/19/2011 at 04z (11:00pm))

This sounding shows 2 caps in the atmosphere. One at about 920 mb and one at between 850 and 700 mb's. This shows the strength of the inversions. Inversions also produce long distance radio reception, so if you are one of those people that likes to go out and listen to long distance radio stations, tonight may be a win or a fail for you.

Looking to the Future

We are going to look at a few soundings to determine if the cap "peels" back and lets some liquid gold in. Remember, focus on the red line.

GFS Sounding in Decatur, Texas Friday Morning 8:00am

This is a perfect example of a "morning inversion". If you avid long distance radio listeners have noticed a spike in the amount of stations received in the morning, this is why. A morning inversion is normal across the US, but what really gets everyone is that this morning cap burns off, but if you live close to the source (Mexican Plateaus), you may see a longer lasting capping inversion (Texas). Now, at 8am, there is a strong inversion here. Surface temp is at 13 degrees Celsius or 55 degrees. And where the peak bump is at 925 mb or so: 69 degrees. So a relatively cool day for Spring here in North Texas. But, we also look at the dew point (green) which is not very healthy. Only 46 degrees at the surface.

GFS Sounding from Decatur, Texas at 18Z (1PM CDT)

Now the difference has become a lot clearer. The surface temps are decreasing with height but, there is a minor cap at 850 mb. There has to be some type of cap there to decrease the forcing, too much equals a LOT of rain and that equals TONS of flooding. Now, the dew points are little more healthier suggest the atmosphere is moistening up a lot more. This may not be healthy though. Dew points are only in the lower to mid 50's. The surface temps are at 77 to 79 degrees suggest healthy surface temps. That 850 mb cap may have some on edge. That cap is at 68 degrees so the cap is weakened but can limit forcing enough to keep us from flooding. And the separation of these lines suggest no cloud cover in the morning or afternoon suggesting potent heating all day.

GFS Sounding in Decatur, Texas at 00Z (8pm)

All right, the moisture is totally in place, there is enough heating, but that 700 and minor 925 mb cap is bugging the crap out of us, and all the lines convergence on the 850 mb level so lets break it down. 1. The dew point temp is showing dew points up to 66 degrees! That is an over load of moisture at the surface and definately shows that the dryline hasn't passed through yet. 2. The surface temp has cooled down a tad from that 78 degrees at 1PM to 74 degrees. Plenty of heating and moisture, its the fact that the inversion is coming back. 3. The cap is a now a tad warmer than the surface, 76 degrees. Minor yes, but will it be enough to flatten the storms? At the 700 mb level is where we REALLY look for a big inversion, but any inversion can flatten a storm if too strong and if the storm has a small updraft. The 700 mb inversion is at around 70 degrees. Making it thin line here to say if the storms will flatten or not. But here's the kicker, 4. The cloud layer at 850 mb. This suggest that the skies may be cloudy suggesting that the storms may be on top of us by then. So the cap, we may not have to worry about. But what really concerns us is if this holds out or not. Cause if this does, a line of storms may come through here Friday Night. If it doesn't, then no storms for us.

DISCLAIMER: This is not the only thing that can predict severe weather. Other dynamics need to be there in order for this to pan out. So the idea here is do not rely solely on soundings. I am just showing the atmospheric dew points and capping inversions to show if the cap will "peel back" or not. Plus, this is GFS looking 140 to 160 hours out. I wouldn't rely on these pics.