Virtual Storm Chase 3

[NL]

I'm with Nick on this one and waiting on the dry-line for some cells firing, i'll go slightly west to Throckmorton, Texas.

CAPE is already 2000+J/Kg with strong CIN over SW Texas presently

and the lifted index

[Mesosphere]

well guys i'm new to Virtual Storm Chasing and thank you Nick F for posting that great tutorial on Virtual Storm Chasing , it has really helped me pick my location today .

It's my first day Virtual Storm Chasing so some of you's may think this location is a bad idea , some may think it is good.

But i'm Going to to go for Archer City , Texas

Looking forward to seeing how it goes

Edited April 3, 2008 by Calum

[Paul Sherman]

That is a pretty good Chase Target Calum. Going to stick with Witchita Falls, this is just North of Archer City, we were chasing around Throckmorton - Archer City last year, remember Lake Kickapoo Guys, could get a Waterspout out of today.

2 main areas today, the Dryline Magic or the bigger threat further East, think this will be a mainly Nocturnal Tornado event though.

Paul S

[Nick F]

1248 update has shrunk the MDT area - but still looks like the cap will hold nicely over our target areas in north central TX to build up large amounts of CAPE until finally breaks explosively late afternoon/early evening due to surface heating and arrival the dry line and shortwave trough from the west... limiting factor for tornadoes still looks to be low-level shear towards the west of the MDT risk area, but as the fcst mentions - a complicated flow regime means that nothing can be ruled out:

...OK/TX LATE THIS AFTERNOON AND OVERNIGHT...

THUNDERSTORM DEVELOPMENT ACROSS OK/N TX WILL LIKELY BE DELAYED UNTIL

LATE AFTERNOON/EVENING BY LINGERING CONVECTIVE INHIBITION WITH THE

ELEVATED MIXED LAYER...AND BY SLOW RECOVERY THIS AFTERNOON OF THE

LOW-LEVEL MASS FIELDS IN THE WAKE OF THE LEAD SHORTWAVE TROUGH.

FORECAST SOUNDINGS ACROSS SRN OK/N TX REVEAL MLCAPE VALUES AOA 2500

J/KG AND RELATIVELY STRONG DEEP LAYER SPEED SHEAR...BUT WEAK

LOW-LEVEL SHEAR THIS AFTERNOON. SUCH PROFILES WILL LIKELY FAVOR

SPLITTING SUPERCELLS CAPABLE OF PRODUCING VERY LARGE HAIL AND

DAMAGING WINDS. A FEW TORNADOES WILL BE POSSIBLE THIS EVENING WITH

THE MORE DISCRETE SUPERCELLS PRIMARILY E OF THE TRIPLE POINT AND S

OF THE COLD FRONT...IF THE LOW-LEVEL WINDS RETURN TO SLY AND SHEAR

INCREASES LIKE SHOWN IN THE 06Z NAM. SHORT TERM ASSESSMENT OF THE

TORNADO THREAT WILL REQUIRE CLOSE ATTENTION TO THE LOW-LEVEL WIND

FIELDS IN THIS COMPLICATED FLOW REGIME. LATER DURING THE EVENING

AND OVERNIGHT...CONVECTION WILL LIKELY EVOLVE INTO AN EXTENSIVE

ENE-WSW ORIENTED BAND ALONG THE COLD FRONT FROM N TX/SE OK ACROSS AR

TO WRN TN...WITH A CONTINUED THREAT FOR HAIL/DAMAGING WINDS AND VERY

HEAVY RAINFALL.

DESPITE A STRONG CAP IN 12Z SOUNDINGS...ISOLATED SUPERCELLS MAY FORM

LATE THIS AFTERNOON JUST W OF THE SJT-DRT CORRIDOR. STRONG SURFACE

HEATING/MIXING WILL REDUCE CONVECTIVE INHIBITION ALONG THE DRYLINE

AS THE BAND OF LEE MOUNTAIN CIRRUS CLEARS THIS AREA...RESULTING IN

STRONG INSTABILITY IN AN ENVIRONMENT WITH SUFFICIENT BULK SHEAR FOR

SUPERCELLS. A STORM OR TWO MAY ALSO FORM OVER THE HIGH TERRAIN W OF

DRT AND MOVE ACROSS THE RIO GRANDE BEFORE WEAKENING LATE THIS

EVENING.

[Paul Sherman]

A very early MD :lol:

MESOSCALE DISCUSSION 0537

NWS STORM PREDICTION CENTER NORMAN OK

1047 AM CDT THU APR 03 2008

AREAS AFFECTED...N-CNTRL/NERN TX INTO S-CNTRL/SERN OK

CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE

VALID 031547Z - 031645Z

TSTMS /INITIALLY ELEVATED/ MAY INCREASE IN COVERAGE AND INTENSITY

LATE THIS MORNING INTO AFTERNOON. INITIALLY LARGE HAIL WOULD BE THE

PRIMARY HAZARD. BUT AS STORMS BECOME MORE SURFACE-BASED...AN

ATTENDANT THREAT OF TORNADOES AND DAMAGING WINDS WILL CONCURRENTLY

INCREASE. THERE IS STILL SOME UNCERTAINTY AS TO WHETHER DEVELOPING

STORMS WILL BECOME SUSTAINED...NECESSITATING A WW THIS MORNING. IT

DOES APPEAR THAT A WW WILL LIKELY BE REQUIRED AT SOME POINT LATER

TODAY.

VISIBLE SATELLITE AND REGIONAL RADAR IMAGERY INDICATE DEEPENING

CUMULUS CONVECTION/EARLY TSTM DEVELOPMENT FROM THE METROPLEX WSWWD

TO NEAR ABI...PERHAPS IN RESPONSE TO A LOW AMPLITUDE PERTURBATION

MOVING ACROSS THE REGION. LATEST MESOANALYSIS INDICATES THAT THIS

ACTIVITY IS OCCURRING WITHIN SYSTEM WARM SECTOR WHICH IS DELINEATED

BY A RAPIDLY RETREATING WARM FRONT WHICH EXTENDED FROM JUST N OF THE

RED RIVER NW OF SPS TO JUST SW OF PRX AS OF 15Z. HOWEVER...BASED ON

THE 12Z OBSERVED SOUNDING FROM FWD AND RUC PROXIMITY SOUNDINGS IT

APPEARS THAT THE DEVELOPING STORMS MAY STILL BE SLIGHTLY ELEVATED

ABOVE A NEAR SURFACE STABLE LAYER.

GIVEN THE MOISTENING LOW-LEVELS AND PRESENCE OF VERY STEEP MIDLEVEL

LAPSE RATES OF AROUND 8.5 C/KM...ENVIRONMENT IS ALREADY MODERATELY

TO STRONGLY UNSTABLE FOR ELEVATED PARCELS WITH MUCAPES OF 2000-3000

J/KG. SHOULD TSTMS BECOME SUSTAINED...THE INITIAL SEVERE THREAT

WILL BE LARGE HAIL. WITH TIME THE BOUNDARY LAYER SHOULD WARM

SUFFICIENTLY SUCH THAT ANY ONGOING ACTIVITY WILL BECOME

PROGRESSIVELY MORE SURFACE-BASED. GIVEN 45-55 KT OF EFFECTIVE BULK

SHEARS AND MODERATELY STRONG LOW-LEVEL SHEAR...THE POTENTIAL WILL

EXIST FOR SUPERCELLS CAPABLE OF TORNADOES...DAMAGING WINDS IN

ADDITION TO THE LARGE HAIL.

[kold weather]

I'm going to stick with where I was before, Frederick. Dry line evident on the sat.images and there is a little convection but not a huge amount that is of any depth right now. Just hope that any of the convection present now over N.Texas doesn't beocme too enlarged and messy because it could limit surface heating a little.

Still for now looks like we are going to have a late afternoon (USA time) event as the cap breaks down (hopefully) along the dryline then things can get going...right now temps are too low to break the cap away from central parts of Texas where moisture profiles are much higher and the cap is pretty much non-exsitant. Interestingly the 16z obs showed most of the chase region only had temps of 40-45F I'm guessing thats pretty normal for the time of year...though away from the deeper convection that should rise pretty rapidly I'd have thought.

[NL]

http://www.spc.noaa.gov/products/md/md0540.htmlw

MD discussion.

[Paul Sherman]

Witchita Falls about to get hammered by a Supercell, nasty looking storm this one.

Paul S

[NL]

Witchita Falls about to get hammered by a Supercell, nasty looking storm this one.

Paul S

Yes Paul lots of CG's+CC with that cell. Just been checking David Drummonds cam, he's along the dry-line

somewhere and lots of convection going on now.

[Nick F]

Yes, line of storms breaking the cap and firing along the northern end of the dry-line up into SW OK:

1800 sfc chart

waiting for it to break out further south now for my target

[NL]

another new MD http://www.spc.noaa.gov/products/md/md0541.html

[Paul Sherman]

LOL

We went to all 4 of those places on the 9th May last year, Good ol Lake Kickapoo!

SEVERE THUNDERSTORM WARNING

NATIONAL WEATHER SERVICE NORMAN OK

258 PM CDT THU APR 3 2008

THE NATIONAL WEATHER SERVICE IN NORMAN HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...

NORTHERN ARCHER COUNTY IN NORTHERN TEXAS...

EASTERN BAYLOR COUNTY IN NORTHERN TEXAS...

SOUTHERN WICHITA COUNTY IN NORTHERN TEXAS...

* UNTIL 345 PM CDT

* AT 258 PM CDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A

SEVERE THUNDERSTORM 6 MILES WEST OF LAKE KICKAPOO...MOVING

NORTHEAST AT 35 MPH. HAIL UP TO THE SIZE OF GOLFBALLS AND WINDS OF 65

MPH ARE LIKELY.

* LOCATIONS IN THE WARNING INCLUDE EXTREME SOUTHWESTERN WICHITA

FALLS...HOLLIDAY...LAKE KICKAPOO...MANKINS AND SCOTLAND.

[Roger J Smith]

I would expect back-building and wave formation southwest of Wichita Falls, would suggest tailing current cell then breaking off to south to a position between Graham and Jacksboro to await larger developments in 2-3 hours.

[Nick F]

Storms atm firing along dry line NE through Wichita Falls aren't in an ideal environment for tornadoes atm, winds aren't strongly backed going down from 700mb to the surface and hence storm-relative helicity/1km wind shear is weak until you get further east and SE - looking at current mesoanalysis:

So ... we could be looking at a few hours yet until storms move into an area with more favourable dynamics further east/SE for tornado development

[Paul Sherman]

DFW ??

[Nick F]

DFW ??

Yes, I'm thinking it could be quite lively for the metroplex area later - be good to get some live TV streaming from DFW should it turn out that way!

[kold weather]

Yeah its about this time in real life I'd go as fast as possible SE towards the main action...however instead I'll just have to watch the webcams.

[Nick F]

TVS on storm crossing Henrietta on the HWY to Heaven:

[Gorky]

That is one obscene hailspike on that Henrietta storm. That could well be dropping Softball sized hail right now.

[Nick F]

The storm cell(s) near Throckmorton is probably the one to watch - have more of an easterly motion than the ones further NE ... heading towards an area of better Storm-Relative Helicity vectors looking at 2100 mesoanalysis - so maybe a tornado warning in the next hr or so:

[kold weather]

Agreed Nick thats the one to watch I think. I think if anything everything has set up a touch further SE then the models progged though they did shift that way last night a little.

Watching David Drummond's livestream, on the move at the moment...really getting me into the severe season mood now...tornadoes till June then hurricanes from then on...oh how I would love to spend a year in the states!

Edited April 3, 2008 by kold weather

[Bilz]

NWS now saying that a collision between the cold front and outflow boundary could lead to rapid storm development south of Oklahoma City. Should hopefully be seeing some storms pop in the next hour down in Norman then.

[Paul Sherman]

NWS now saying that a collision between the cold front and outflow boundary could lead to rapid storm development south of Oklahoma City. Should hopefully be seeing some storms pop in the next hour down in Norman then.

Yep

Thats the Old Outflow Boundary from the Witchita Falls Storm much earlier and the SE Moving Cold Front, thankfully the CF Should not interfere with the Throckmorton Cell, If one is going to Tornado today in that part of the world then that is the one.

Paul S

[kold weather]

Nice big storm clearly visable on the stream I'm watching now with a clear overshooting top. Will be interesting to see if anything does develop Bliz.

Paul---I think David is trying to intercept that cell does look strong as I said nice overshooting top.

Edited April 3, 2008 by kold weather

[Cookie]

Nice big storm clearly visable on the stream I'm watching now with a clear overshooting top. Will be interesting to see if anything does develop Bliz.

what stream are you watching mate?