Monday, May 10, 2010

Post date: May 10, 2010 1:06:03 PM

8:00 am CDT

This is the day that we've all been patiently waiting for. Now let's see if it can possibly live up to all the hype!

Overnight, the area of interest has shifted to the south... and a bit to the east as well. Our initial relocation from Norman this morning should be a very short one, and then we will tweak our location to hopefully be well-positioned when things start firing up. One problem is that it's very likely that the cells may not fire up until late afternoon, but all we can do is be in a good spot early (since the "chaser convergence" will probably be extreme), and then sit... and wait... and hope.

Here's the SPC's tornado probability map for today:

...and here is the detailed report from the SPC, as of 7:33 am CDT:

SPC AC 101233

DAY 1 CONVECTIVE OUTLOOK

NWS STORM PREDICTION CENTER NORMAN OK

0733 AM CDT MON MAY 10 2010

VALID 101300Z - 111200Z

...THERE IS A HIGH RISK OF SVR TSTMS LATE THIS AFTERNOON/EVENING FOR

CENTRAL/NE OK AND SE KS...

...THERE IS A MDT RISK OF SVR TSTMS SURROUNDING THE HIGH RISK IN

KS...OK...SW MO...AND NW AR...

...THERE IS A SLGT RISK OF SVR TSTMS FROM CENTRAL/NW TX TO THE

CENTRAL PLAINS AND MID MS VALLEY THROUGH TONIGHT...

...A FEW STRONG/LONG-TRACK TORNADOES...ALONG WITH VERY LARGE HAIL

AND DAMAGING WINDS...WILL BE POSSIBLE THIS AFTERNOON/EVENING ACROSS

CENTRAL/NE OK AND EXTREME S CENTRAL/SE KS...

...SRN/CENTRAL PLAINS THIS AFTERNOON TO MO OVERNIGHT...

RAPID CHANGES ARE EXPECTED TODAY ACROSS THE SRN/CENTRAL PLAINS AS A

PRONOUNCED SHORTWAVE TROUGH NEAR THE FOUR CORNERS MOVES QUICKLY EWD

TO CENTRAL KS/NRN OK BY THIS EVENING...AND CONTINUES ENEWD TO THE

MID MS VALLEY OVERNIGHT. A SURFACE WARM FRONT AND ASSOCIATED MOIST

AIR MASS /BOUNDARY LAYER DEWPOINTS OF 65-70 F/ WILL SURGE NWD FROM

NW/N CENTRAL TX TO CENTRAL AND NRN OK BY MID-LATE AFTERNOON. THIS

MOISTENING WILL OCCUR BENEATH A PLUME OF STEEP MIDLEVEL LAPSE RATES

AND IN RESPONSE TO EWD DEVELOPMENT OF THE SURFACE CYCLONE ACROSS

SW/S CENTRAL KS. THE MOST FAVORABLE PHASING OF THE UNSTABLE WARM

SECTOR AND STRONG VERTICAL SHEAR ENVIRONMENT WILL OCCUR LATE THIS

AFTERNOON/EVENING ACROSS CENTRAL/N CENTRAL/NE OK...AND THE ADJACENT

BORDER COUNTIES IN KS. OVERNIGHT...THE BELT OF STRONGER FORCING FOR

ASCENT WILL ACCELERATE ENEWD OVER MO AT A FASTER RATE THAN THE LOW

LEVELS WILL BE ABLE TO MOISTEN/DESTABILIZE...RESULTING IN A DECREASE

IN THE SEVERE STORM/TORNADO RISK LATER TONIGHT.

DISCRETE THUNDERSTORM INITIATION IS EXPECTED BY 18-20Z IN SW KS NEAR

THE SURFACE LOW AND LEFT EXIT REGION OF THE MID-UPPER JET.

ADDITIONAL DEVELOPMENT WILL OCCUR FARTHER SE ALONG THE SRN KS/NRN OK

DRYLINE AROUND 21-22Z...WITH ISOLATED STORMS POSSIBLE SWD INTO

CENTRAL OK AND NW TX CLOSER TO 22-00Z. THE STRONG DEEP-LAYER SHEAR

ENVIRONMENT NEAR THE MID-UPPER JET CORE SUGGESTS THAT STORMS MAY

TAKE UP TO AN HOUR OR SO TO MATURE. HOWEVER...EFFECTIVE SRH OF

400-600 M2/S2...BOUNDARY LAYER DEWPOINTS OF 65-70 F AND MLCAPE OF

2000-3500 J/KG ALL FAVOR THE POTENTIAL FOR STRONG/LONG-TRACK

TORNADOES IN THE MDT-HIGH RISK AREAS. THE TORNADO AND LARGE HAIL

THREAT SHOULD MAXIMIZE FROM ABOUT 22-02Z IN OK/SE KS...WITH A

GRADUAL EVOLUTION TO A MORE LINEAR CONVECTIVE MODE WITH DAMAGING

WINDS/LARGE HAIL OVERNIGHT ACROSS MO.

POTENTIAL CONCERNS WILL BE THE LATE ARRIVAL AND NARROW WIDTH OF THE

WARM SECTOR COMPARED TO THE STRONG VERTICAL SHEAR PROFILES AND FAST

STORM MOTIONS. A COMPARISON OF EXPECTED 45-50 KT STORM MOTIONS WITH

WARM SECTOR WIDTH/PROGRESSION SUGGESTS A 2-3 HOUR WINDOW FOR

SUPERCELLS TO MATURE AND REMAIN WITHIN THE CORRIDOR OF STRONGER

INSTABILITY ACROSS EXTREME SRN/SERN KS AND NRN/NERN OK THIS EVENING.

STILL...IT APPEARS THIS WINDOW OF OPPORTUNITY WILL BE SUFFICIENTLY

LONG TO SUPPORT A SIGNIFICANT SUPERCELL/TORNADO RISK FOR A FEW HOURS

LATE THIS AFTERNOON/EVENING...INCLUDING THE WICHITA...TULSA...AND

OKLAHOMA CITY METROPOLITAN AREAS.

..THOMPSON/HURLBUT.. 05/10/2010

12:00 pm CDT

The 1630z is out, and here's what it looks like:

We're headed north, but we probably won't go far. There are chasers all over the place! Take a look...

10:00 pm CDT

Well, it was a good chase day, because we ended up seeing a tornado! (Well, actually there was a second one --- very quick, apparently --- but I didn't see it myself.) It was (or "they were") in north-central Oklahoma, near Wakita. There were others in that vicinity, too, because we saw many twisted and snapped trees and about six or seven tractor trailers overturned along the side of the highway. There was also baseball to softball-size hail --- and lots of it --- in Cherokee, OK, but fortunately for us, it had already fallen by the time we blasted through town. The worst of it, though, (so far) was apparently back in the Norman, OK and/or Moore, OK vicinity. See http://www.cnn.com/2010/US/weather/05/10/severe.storms/?hpt=T3 for more on that... Why in the world does the Moore, OK get hit so frequently? Hard to fathom...

Anyway, the day wasn't as great for chasing as we would have hoped, however. Everything was moving so fast that it was essentially impossible to keep up with it. All you could hope to do, really, was position yourself, be lucky enough to be in the right place, and then watch the cells as they blew past, lightning fast. Everything was moving between 45 and 70 knots. It was incredible... and maddening! Add to that the sheer numbers of chasers out there, and it made for very very difficult chasing. All in all, I guess we were lucky to have seen as much as we did!

Anyway, here's our travel map for the day. I'll post a few pictures later, though there won't be any still shots of the tornado. We weren't able to get out of the vehicles, given the conditions.

11:45 pm CDT

Okay, I've now finished uploading some pictures from the day. You can find them HERE.