Chase 2011 - Day 22 Discussion

[Paul Sherman]

Changeover Day..................But this might just be reachable to the 5% Tornado Risk if we can lock and load and get away from DFW By about 5pm

DAY 1 CONVECTIVE OUTLOOK

NWS STORM PREDICTION CENTER NORMAN OK

1249 AM CDT SAT MAY 21 2011

VALID 211200Z - 221200Z

...THERE IS A SLGT RISK OF SVR TSTMS OVER ERN PORTIONS OF THE SRN

AND CNTRL PLAINS INTO THE LOWER-MID MS VALLEY...

...SYNOPSIS...

LARGE CUTOFF UPPER LOW SITUATED OVER THE HIGH PLAINS WILL DRIFT

SLOWLY EWD TODAY WHILE SEVERAL SHORTWAVE TROUGHS ROTATE THROUGH THIS

FEATURE. EARLY SATURDAY AN OCCLUDED FRONT WILL EXTEND FROM A SURFACE

LOW OVER THE DAKOTAS SWD INTO THE CNTRL PLAINS. THERE IT WILL

TRANSITION TO A PACIFIC FRONT/DRYLINE AND EXTEND SWD THROUGH THE

REMAINDER CNTRL OK TO NEAR THE BIG BEND AREA OF TX. SRN PORTION OF

THIS FRONT WILL ADVANCE INTO ERN OK AND NERN TX DURING THE DAY

BEFORE RETREATING WWD ONCE AGAIN OVERNIGHT.

...CNTRL AND SRN PLAINS INTO THE LOWER-MID MS VALLEY...

THE ONGOING MCS FROM THE LOWER MS VALLEY SWWD THROUGH SERN TX WILL

CONTINUE THROUGH THE EARLY MORNING WHILE GRADUALLY WEAKENING. IN

WAKE OF MCS...MODEST SLY BOUNDARY LAYER FLOW WILL MAINTAIN MID TO

UPPER 60S DEWPOINTS IN THE SRN PLAINS AND LOWER MS VALLEY WARM

SECTOR WITH LOW-MID 60S FARTHER NORTH THROUGH THE CNTRL PLAINS. THIS

IN CONJUNCTION WITH EWD ADVECTING EML PLUME WILL CONTRIBUTE TO

POTENTIAL FOR AXIS OF STRONG INSTABILITY. AS THE MOIST BOUNDARY

LAYER WARMS MLCAPE WILL LIKELY INCREASE TO 3000+ J/KG FROM ERN TX TO

AROUND 2000+ J/KG FARTHER NORTH INTO THE CNTRL PLAINS AND THE MID MS

VALLEY.

VORT MAX NOW LOCATED OVER THE SWRN STATES WILL ROTATE THROUGH THE

BASE OF THE UPPER LOW AND INTO THE SRN PLAINS AND MID MS VALLEY

DURING THE AFTERNOON AND EVENING. DEEPER FORCING ACCOMPANYING THIS

FEATURE WILL AUGMENT POTENTIAL FOR ISOLATED TO WIDELY SCATTERED

STORMS TO DEVELOP ALONG DRYLINE/PACIFIC FRONT FROM CNTRL TX NWD

THROUGH ERN OK...ERN KS AND NEB AS CAP WEAKENS. EFFECTIVE VERTICAL

SHEAR WILL SUPPORT SUPERCELLS FROM TX THROUGH OK AND KS INTO THE

LOWER MS VALLEY WITH MORE MARGINAL SHEAR WITH NWD EXTENT THROUGH ERN

KS AND NEB. PRIMARY INITIAL THREAT WILL BE LARGE HAIL WITH ISOLATED

VERY LARGE HAIL ALSO POSSIBLE GIVEN EXPECTED HIGH VALUES OF

NORMALIZED CAPE ASSOCIATED WITH STEEP LAPSE RATES. ISOLATED

TORNADOES WILL ALSO BE POSSIBLE...ESPECIALLY TOWARD EARLY EVENING

OVER THE SRN PLAINS AND LOWER MS VALLEY AS LLJ STRENGTHENS AND

BEFORE THE BOUNDARY LAYER BEGINS TO STABILIZE. ACTIVITY WILL

CONTINUE INTO THE LOWER-MID MS VALLEYS OVERNIGHT POSSIBLY EVOLVING

INTO MCS CLUSTERS WITH A THREAT FOR ISOLATED DAMAGING WIND AND HAIL.

[Arron]

Quick update, just waiting at DFW for the last passenger and then going to head south to catch the line of storms that have fired. Should hopefully be within the next 30 minutes or so It's JUICY here!

Edited May 21, 2011 by Smokes

[Arron]

And we're off! Heading south towards Midlothian and then we'll take a check on data.

[Paul]

Are you going to be streaming? It's not live at the moment.

[Arron]

Sorted!

[Paul]

Thanks mate

[Paul]

Team currently headed towards watch area:

http://www.spc.noaa.gov/products/watch/ww0316.html

Live stream

http://www.netweather.tv/index.cgi?action=chaselive;sess=

[Gorky]

Letting you guys know I came south also and have set up near Ardmore. Watching some TCU try and make it just to my East at the moment. Magic hour is approaching so hopefully it pays off!

[Nick F]

Interesting tornado warned cell with a hook SE of Lampasas or NE of Burnet, central texas in the cluster of storms which the team are on the northern side. I see they have stopped for dinner at Burger King ...

BULLETIN - EAS ACTIVATION REQUESTED

TORNADO WARNING

NATIONAL WEATHER SERVICE AUSTIN/SAN ANTONIO TX

727 PM CDT SAT MAY 21 2011

THE NATIONAL WEATHER SERVICE IN AUSTIN SAN ANTONIO HAS ISSUED A

* TORNADO WARNING FOR...

CENTRAL BURNET COUNTY...

EXTREME WEST CENTRAL WILLIAMSON COUNTY...

* UNTIL 800 PM CDT.

* AT 727 PM CDT...NWS METEOROLOGISTS HAVE DETECTED A SEVERE

THUNDERSTORM CAPABLE OF PRODUCING A TORNADO NEAR SHADY GROVE...OR

ABOUT 6 MILES NORTHEAST OF BURNET...MOVING EAST AT 10 MPH.

* SOME LOCATIONS IN THE WARNING INCLUDE BERTRAM...JOPPA AND BRIGGS.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

IF YOU ARE IN A MOBILE HOME OR VEHICLE...GET OUT AND GO TO A STURDY

SHELTER. IF NO SHELTER IS AVAILABLE...LIE FLAT IN THE NEAREST DITCH

OR OTHER LOW SPOT AND COVER YOUR HEAD WITH YOUR HANDS.

A SEVERE THUNDERSTORM WATCH REMAINS IN EFFECT UNTIL 900 PM CDT

SATURDAY EVENING FOR SOUTH CENTRAL TEXAS

[Arron]

A bit too far south for us unfortunately Nick as we don't want to get out of position for tomorrow. Going to try and get some lighting shots from these cells just to our south then find some food and a hotel

[Arron]

Sat just waiting for the rain to clear, then get some lightning shots

Steam should look good!

[Paul Sherman]

Did not get away from DFW until after 5pm so would not have made the Ardmore Beast anyway so dropped 60 miles south of Dallas for the Central Texas Supercells and played with some hail and Lightning. Congratulations to Nathan who was on a great storm. This time last year leaving at 2pm allowed us to get the Wynewood Cell in much the same area but this year we just could not make it.

1st Chase day proper tomorrow so should be in full chase mode for Tour 3

[Gorky]

To be honest, it was real touch and go whether these cells got going anyway. You'd probably already started the trip south before the TCU even started, the SPC last meso was very unconvincing about the OK play even getting started so even if you had set off earlier, it would have been a risk to come north and take a possible bust over some guaranteed action further south. If I'd been in your position, I think I'd have headed south. Too jaded after the last few days to risk another bust. I had put myself in a position where it was all or nothing with the OK target and luckily, it worked out. I'm still amazed at where all the chasers came from. Only about 3 or 4 spotter network icons in the area and mine was one of two reports of the first tornado (although I only saw it in funnel form between trees whilst driving). By the time it was cranking up 20 mins later, about 40 vehicles were all over my little piece of highway I was watching from. I think a fair amount were locals however but it was crazy to see them all come out of the woodwork!

As it happens it appears my original target as of yesterday, and the main reason I abandoned that chase to get into position in Salina was hit by an EF0 tornado (Topeka). A potentiallly very damaging tornado went through Reading also not too far from there. Paul Knightly stayed up north looking at Spotter Network and UKWW so hopefully he has some photos of those storms!