Severe Outbreak - This Weekend - Discussion

[Paul Sherman]

Ok so why is this thread needed and not in the Virtual Thread.................Well at the drop of a hat both myself and Arron decided to make the 10 hour flight across the pond yesterday to chase this 3 day Outbreak as it looked too good to miss.

We landed at 1pm at DFW & Drove up Highway287 to chase some Storms near Amarillo, this also puts us in a good position for our first proper chase day today and some Dryline action, looking likely we will target the Kansas and Western Oklahoma part of today and the 10% Tornado Risk.

Please feel free to post info into this thread as the chases are in progress.

Target today looking like Woodward upto Greensburg area as it stands and starting in Amarillo.

Btw next Tornado will be my 50th!

Paul S

[Gorky]

I'm liking the look of NW Ks here... Colby/Goodland area. Seems like a higher chance of storms, better helicity, though more meager moisture. The more isolated storms down south may be a nicer chase target, presuming they pop though

[user700]

James Menzies live stream with Paul and Arron on chasertv

http://content.wdtinc.com/popout/index.php?M=14613&C=20643&O=10432

Good luck today

Edited April 12, 2012 by danieluk

[Nick F]

Liking the look of the NE TX Panhandle, Canadian as a target, skies clearing now and RUC showing 3000j/kg SBCAPE and strong low-level shear to play with in next few hours near/along advancing the dryline.

Good luck though boys, stream is working a treat, hope it keeps up when it gets interesting.

[dallas]

yes great feed, hope it stands up like that for the tours

[dallas]

http://www.spc.noaa.gov/products/md/md0500.html

Mesoscale discussion 500 looks interesting

[user700]

MESOSCALE DISCUSSION 0501

NWS STORM PREDICTION CENTER NORMAN OK

0502 PM CDT THU APR 12 2012

AREAS AFFECTED...EASTERN CO/SOUTHWEST NEB/WESTERN KS

CONCERNING...TORNADO WATCH 157...

VALID 122202Z - 122330Z

THE SEVERE WEATHER THREAT FOR TORNADO WATCH 157 CONTINUES.

TORNADO WATCH 157 CONTINUES UNTIL 02Z...WITH CONTINUED POTENTIAL FOR

TORNADOES/LARGE HAIL THROUGH LATE AFTERNOON/EARLY EVENING. A SEVERE

THREAT /MAINLY HAIL/ MAY DEVELOP NORTHWARD OUT OF WW 157...SUCH THAT

A WATCH EXTENSION/NEW SEVERE TSTM WATCH COULD BE NEEDED.

PRIMARY SHORT-TERM SEVERE THREAT WILL LIKELY REMAIN ACROSS THE

NORTHEAST CO/SOUTHWEST NEB/NORTHWEST KS BORDER REGION THROUGH LATE

AFTERNOON/EARLY EVENING. SATELLITE IMAGERY SUGGESTS THAT FORCING FOR

ASCENT/UPPER JET EXIT REGION IS INFLUENCING THIS REGION...AND THIS

CORRIDOR IS LOCATED NEAR/JUST NORTH OF A SURFACE TRIPLE POINT WITH A

SURFACE LOW ACROSS EAST-CENTRAL/NORTHEAST CO AND A SOUTHWARD

EXTENDING DRYLINE ACROSS THE HIGH PLAINS. SUPERCELLS CAPABLE OF

LARGE HAIL AND A TORNADO THREAT WILL REMAIN POSSIBLE INTO EARLY

EVENING WITHIN A HIGHLY SHEARED ENVIRONMENT...WITH A LARGE HAIL

THREAT ALSO POSSIBLE WITH INCREASINGLY ELEVATED STORMS SPREADING

NORTH OF THE SURFACE WARM FRONT ACROSS FAR SOUTHWEST NEB.

FARTHER SOUTH...RECENT SATELLITE TRENDS ARE INDICATIVE OF DEEPENING

CU FIELD NEAR THE DRYLINE ALONG CO/KS BORDER...WHICH COULD LEAD TO

AN UPSWING OF DEEP CONVECTION OVER THE NEXT FEW HOURS...AT LEAST ON

AN ISOLATED BASIS. GIVEN SUCH DEVELOPMENT...SUPERCELLS CAPABLE OF

LARGE HAIL WILL BE POSSIBLE...AND A TORNADO THREAT WILL EXIST AS

WELL ESPECIALLY GIVEN NEAR/POST-SUNSET POTENTIAL FOR A NOCTURNAL LOW

LEVEL JET INCREASE AND ABATED BOUNDARY LAYER MIXING.

[user700]

Storms popping up on radar now

Goodland KS Radar

[dallas]

Pity the live feed is down

[nsrobins]

Could be an 'good' decision to do a sneaky chase Paul as Saturday in particular looks especially active along the I35 corridor. You'll see as you get up and about today that the SPC have gone high risk on the 2-day which I think has only happened once before and the language is very serious indeed.

Increasing threat into the evening but the only suspicious parameter is the modelling of how the surface low deepens and how quickly and hence the onset of the decent low-level shear is a tad in question just now. NAM taking over from GFS will give a clearer picture by this evening.

Incidentally, could you post the link(s) where your stream is hosted.

[Dan the Man]

TOR:CON Indices for the next few days...

Friday April 13

OK southwest, west, north-central - 4

KS south-central - 4

Friday Night April 13

OK north - 5

KS southeast, south-central - 5

Saturday April 14

IA northwest - 4

IA southwest - 4 to 5

IA rest - 3 to 4

IL northwest - 3

KS south-central - 7

KS rest of central, east - 5 to 6

MN southwest - 4

MN southeast - 3

MO north - 4

NE southeast - 5

NE northeast - 4 to 5

OK northwest, north-central - 7

OK southwest - 5

SD southeast - 4

TX east panhandle - 5

WI southwest -3

Other areas - less than 2

Saturday Night April 14

IA west - 5

KS south-central, east - 6

OK north, central, west - 6

MN southwest - 5

MO northwest - 4

NE east - 5

TX north-central - 5

Sunday April 15

AR northwest - 4

IA east - 6

IL northwest - 4

KS southeast - 4

MN southeast -6

MN south - 4

MO - 4

OK southeast - 4

TX northeast - 4

Oklahoma and Kansas the place to be for chasers. Extremely dangerous few days coming up.

Edited April 13, 2012 by Dan the Man

[Paul Sherman]

Very Very Serious Wordings from the SPC.

I have been doing this for 8 years and have never seen a 65% Hatched Box on a High Risk other than the 2006 event mentioned above, I think there were well over 100 Tornadoes that day, To Put this into perspective last years May 24th High Risk had a 30% Hatched Box.

We will be playing the Oklahoma and Kansas Border as Models stand at the moment obviously with some fine tuning and I-35 Is a decent enough road with lots of East to West Options, the only problems is East of Here like the May 10th 2010 High Risk when Roads become much more unfavourable and Storm Speeds will outrun you in an instant and trees and hills become problems, Hoping the Dryline sets up further West tbh.

Tonight also sees a risk of Night-Time Tornadoes so we will have to be on our guard from these as well.

Paul S

[Harry]

Very Very Serious Wordings from the SPC.

I have been doing this for 8 years and have never seen a 65% Hatched Box on a High Risk other than the 2006 event mentioned above, I think there were well over 100 Tornadoes that day, To Put this into perspective last years May 24th High Risk had a 30% Hatched Box.

We will be playing the Oklahoma and Kansas Border as Models stand at the moment obviously with some fine tuning and I-35 Is a decent enough road with lots of East to West Options, the only problems is East of Here like the May 10th 2010 High Risk when Roads become much more unfavourable and Storm Speeds will outrun you in an instant and trees and hills become problems, Hoping the Dryline sets up further West tbh.

Tonight also sees a risk of Night-Time Tornadoes so we will have to be on our guard from these as well.

Paul S

To say I'm jealous is a huge understatement

Good luck!!!!

Edited April 13, 2012 by Harry

[Staffordshire]

Good luck!

And stay safe!

Very Very Serious Wordings from the SPC.

I have been doing this for 8 years and have never seen a 65% Hatched Box on a High Risk other than the 2006 event mentioned above, I think there were well over 100 Tornadoes that day, To Put this into perspective last years May 24th High Risk had a 30% Hatched Box.

We will be playing the Oklahoma and Kansas Border as Models stand at the moment obviously with some fine tuning and I-35 Is a decent enough road with lots of East to West Options, the only problems is East of Here like the May 10th 2010 High Risk when Roads become much more unfavourable and Storm Speeds will outrun you in an instant and trees and hills become problems, Hoping the Dryline sets up further West tbh.

Tonight also sees a risk of Night-Time Tornadoes so we will have to be on our guard from these as well.

Paul S

[Gorky]

Weirdly, they could maintain the 60% tomorrow and drop to a moderate risk if the current 60% is entirely for hail threat 60% Tornado chance is very rare. Only happened once on April 7th 2006 if I remember rightly. Last years super outbreak only mustered a 45% (although a 90% would easily have verified around huntsville!!!). Given the expected widespread nature of the outbreak tomorrow, I'm expecting larger risk area at lower probabilities, maybe pushing 45% if a focusing mechanism for initiation is obvious early on in the day.

[user700]

SPC convective outlook for Saturday

Good luck stay safe!

[chionomaniac]

How fast are the likely storms predicted to move? Is it a case of letting storms fire past you or latching onto a cell and staying with it?

[Gorky]

Out of interest, what's your plans for today? I noticed you made it up all the way to Hays yesterday. I presume it's a trip back down to NW OK today, or are you going to play a lower threat area into KS to keep flexible for saturday? These are the sort of decisions I hate when storm chasing

SPC convective outlook for Saturday

Good luck stay safe!

you always have to worry when the outlook itself looks like a tornado :o

[Supercell 89]

Good Luck guys and stay safe!

[nsrobins]

Storm motions for Sat evening ~45/50kn from the SW. Not good!

Looking at latest NAM I'd be thinking of a corridor just west of the I35, maybe as far as the 281 betwen Alva and Medicine Lodge on the OK/KS border. That estimate is based largely on the dryline setting-up just west of there. The only problem with being right on the money is with those storm motions - you might spend the next four hours chasing their tails.

Instability is not an issue but as I said earlier it's all about tracking the surface synoptics during the day to see where the surface low forms - this will determine the location of the highest vertical shear values and hence highest tornadic potential early doors.

As darkness falls it all goes mad and if cells can stay discrete some long-tracked nightime tornados look likely. Urck!

[Arron]

Todays chase is being left up to me Heading towards Clinton, OK for some lunch and then go from there. Aiming to end up in north Oklahoma tonight ready for tomorrow

[chionomaniac]

Good luck Arron. Heres hoping you can help Paul achieve his half century before the big day tomorrow. Don't end up in the path of one tonight when asleep!

[user700]

ATM my chase target for Saturday is Medford Oklahoma.

Daniel

Edited April 13, 2012 by danieluk

[Arron]

Updated SPC forcast for today contains this:

ANY STORM WHICH DOES DEVELOP WILL BE CAPABLE OF

PRODUCING VERY LARGE HAIL...DAMAGING WINDS...AND POTENTIALLY

STRONG/LONG-LIVED TORNADOES.

[user700]

MESOSCALE DISCUSSION 0507

NWS STORM PREDICTION CENTER NORMAN OK

1210 PM CDT FRI APR 13 2012

AREAS AFFECTED...NWRN TX THROUGH SWRN OK

CONCERNING...SEVERE POTENTIAL...WATCH LIKELY

VALID 131710Z - 131915Z

STORMS ARE EXPECTED TO DEVELOP SOON FROM NWRN TX INTO SWRN OK.

INITIAL PRIMARY THREAT WILL BE SUPERCELLS WITH LARGE HAIL DURING THE

AFTERNOON WITH THREAT FOR ISOLATED TORNADOES INCREASING DURING THE

EARLY EVENING. AREA IS BEING MONITORED FOR A WW.

A PRE-FRONTAL BOUNDARY EXTENDS FROM ERN KS SWWD THROUGH WRN OK AND

NWRN TX. MOIST AXIS WITH MID-UPPER 60S DEWPOINTS ARE IN PLACE IN

WARM SECTOR BENEATH 7-7.5 C/KM MID LEVEL LAPSE RATES PROMOTING AN

AXIS OF 2000-2500 J/KG MLCAPE. THE ATMOSPHERE SHOULD DESTABILIZE

FURTHER AS LOW CLOUDS MIX OUT AND THE BOUNDARY LAYER WARMS. VISIBLE

IMAGERY CONTINUES TO SHOW AN INCREASE IN CUMULUS DEVELOPMENT IN

VICINITY OF THE CONVERGENCE BOUNDARY OVER NWRN TX INTO SWRN OK AS

WELL AS A LITTLE FARTHER EAST INTO S-CNTRL OK WITHIN ZONE OF WEAK

WARM ADVECTION. MORNING RAOB DATA FROM FWD AND OKC INDICATED A

MODEST INVERSION AROUND 750 MB...AND LATEST OBJECTIVE ANALYSIS SHOW

ONLY A WEAK CAP REMAINING. INDICATIONS ARE THAT THUNDERSTORMS MAY

SOON DEVELOP IN THIS REGION. EFFECTIVE DEEP LAYER SHEAR AROUND 40 KT

SUPPORTS SUPERCELLS. LOW LEVEL WINDS HAVE BEEN VEERING AND WEAKENING

AS PRIMARY LLJ SHIFTS THROUGH THE MS VALLEY IN ASSOCIATION WITH

SHORTWAVE TROUGH EJECTING NEWD THROUGH ERN SD. THIS MAY DELAY A MORE

ROBUST TORNADO THREAT UNTIL EARLY EVENING WHEN THE LLJ WILL

STRENGTHEN OVER THE SRN PLAINS.