[Sam Jowett]

Looking like some very severe weather likely across the central plains late Saturday and in to Saturday night. Some very strong language being used in the day 2 convective outlook from SPC, pasted below. The potential for strong tonrnadoes and a tornado outbreak is high. Unusual to see such strong language used in a day 2 outlook...

DAY 2 CONVECTIVE OUTLOOK RESENT 1
NWS STORM PREDICTION CENTER NORMAN OK
0102 AM CDT FRI APR 13 2012

VALID 141200Z - 151200Z

...THERE IS A HIGH RISK OF SVR TSTMS ACROSS PARTS OF OK AND KS...

...THERE IS A MDT RISK OF SVR TSTMS ACROSS PARTS OF NW TX...CNTRL
AND WRN OK...CNTRL AND ERN KS...SE NEB...NW MO AND FAR SW IA...

...THERE IS A SLGT RISK OF SVR TSTMS ACROSS PARTS OF THE MID-MO
VALLEY...UPPER MS VALLEY...SRN PLAINS AND CNTRL PLAINS...

TORNADO OUTBREAK LIKELY ACROSS THE SRN AND CNTRL PLAINS NWD INTO THE
MID-MO VALLEY FROM SATURDAY AFTERNOON THROUGH SATURDAY NIGHT

...SRN AND CNTRL PLAINS...
AN IMPRESSIVE UPPER-LEVEL LOW WILL MOVE EWD ACROSS FOUR CORNERS
REGION SATURDAY AS A POWERFUL 90 TO 110 KT MID-LEVEL JET EJECTS NEWD
INTO THE SRN AND CNTRL PLAINS. AHEAD OF THE SYSTEM...A CORRIDOR OF
MODERATE TO STRONG INSTABILITY IS FORECAST ACROSS ECNTRL KS...CNTRL
OK INTO NW TX. THIS COMBINED WITH STEEP MID-LEVEL LAPSE RATES AND
STRONG LOW-LEVEL SHEAR WILL BE VERY FAVORABLE FOR SEVERE STORMS AND
A TORNADO OUTBREAK WILL BE LIKELY ACROSS THE SRN AND CNTRL PLAINS
FROM LATE SATURDAY AFTERNOON LASTING THROUGH THE EVENING AND INTO
THE OVERNIGHT PERIOD.

NAM AND NAMKF FORECAST SOUNDINGS AT 00Z SATURDAY EVENING FROM SALINA
KS SWD TO AROUND OKLAHOMA CITY SHOW MLCAPE VALUES FROM 2000 TO 3000
J/KG WITH 0-6 KM SHEAR IN THE 60 TO 75 KT RANGE. IN
ADDITION...HODOGRAPHS ARE LARGE AND LOOPED WITH 0-1 KM SHEAR VALUES
IN THE 30 TO 40 KT RANGE. THIS ENVIRONMENT SHOULD BE VERY FAVORABLE
FOR SUPERCELLS AND TORNADOES. 0-3 KM STORM RELATIVE HELICITIES ARE
FORECAST TO BE AROUND 400 M2/S2 WHICH IS IDEAL FOR STRONG TORNADOES
AND A TORNADO OUTBREAK APPEARS LIKELY. THE GREATEST THREAT FOR
SIGNIFICANT TORNADOES SHOULD EXIST SATURDAY EVENING FROM SALINA SWD
TO OKLAHOMA CITY. 700 TO 500 MB LAPSE RATES AROUND 7.5 C/KM WILL
ALSO BE FAVORABLE FOR LARGE HAIL AND HAIL GREATER THAN 2 INCHES WILL
BE POSSIBLE THE MORE INTENSE SUPERCELLS. A WIND DAMAGE THREAT WILL
ALSO EXIST DUE TO THE EXPECTED INTENSE NATURE OF THE STORMS.

THE MAIN CONCERN FOR THIS FORECAST IS CONVECTIVE COVERAGE. MANY OF
THE MODELS DO NOT DEVELOP NUMEROUS THUNDERSTORMS ALONG THE DRYLINE.
IN SPITE OF THIS...THE MODELS DIMINISH THE CAP ACROSS THE SRN AND
CNTRL PLAINS LATE SATURDAY AFTERNOON SO THIS BRINGS THE MODELS INTO
QUESTION. IN ADDITION...THE MODELS DRIVE A BAND OF LARGE-SCALE
ASCENT ACROSS CNTRL KS DURING THE EARLY EVENING SUGGESTING MANY
STORMS SHOULD INITIATE WITH STORMS INITIATING SWD WITH TIME EARLY
SATURDAY EVENING AS THE LOW-LEVEL JET STRENGTHENS. THESE FACTORS
COMBINED WITH SFC DEWPOINTS IN THE LOWER TO MID 60S F AND VERY
FAVORABLE LOW-LEVEL SHEAR PROFILES SHOULD PRODUCE AND ENVIRONMENT
FAVORABLE FOR A TORNADO OUTBREAK. AFTER COLLABORATION WITH WFOS
WICHITA...NORMAN...TOPEKA...TULSA AND DODGE CITY...A HIGH RISK WILL
BE ISSUED DUE TO THE POTENTIAL FOR A HIGH-END LIFE THREATENING EVENT
ACROSS THE SRN AND CNTRL PLAINS.

...MID-MO VALLEY/UPPER MS VALLEY...
AN IMPRESSIVE UPPER-LEVEL LOW WILL MOVE ACROSS THE FOUR CORNERS
REGION SATURDAY. AT THE SFC...A LOW SHOULD MOVE ACROSS NEB WITH A
WARM FRONT EXTENDING EWD ACROSS IA. THUNDERSTORMS SHOULD BE ONGOING
ALONG THIS BOUNDARY WITH STORMS EXPANDING NWD INTO THE UPPER MS
VALLEY. SOUTH OF THE BOUNDARY...THE MODELS DEVELOP MODERATE
INSTABILITY WITH A DRYLINE LOCATED IN ECNTRL NEB. THUNDERSTORMS THAT
INITIATE ALONG THE DRYLINE AND EWD ACROSS THE WARM SECTOR WILL
LIKELY HAVE AN ENHANCED SEVERE THREAT. STRONG DEEP LAYER SHEAR AND
ENHANCED LOW-LEVEL SHEAR WILL BE FAVORABLE FOR SUPERCELLS AND
TORNADOES. A FEW STRONG TORNADOES MAY OCCUR WITH THE MORE DOMINANT
SUPERCELLS ESPECIALLY AS THE LOW-LEVEL JET STRENGTHENS SATURDAY
EVENING. ALTHOUGH A TORNADO OUTBREAK WILL BE POSSIBLE ACROSS PARTS
OF THE REGION...THE GREATEST MOISTURE RETURN SHOULD REMAIN FURTHER
TO THE SOUTH SUGGESTING THE HIGHEST TORNADO THREAT SHOULD EXIST
ACROSS SERN NEB...SW IA...NW MO AND ERN KS WHERE A MODERATE RISK IS
LOCATED.

...NW TX/WCNTRL TX...
AN IMPRESSIVE UPPER-LEVEL LOW WILL MOVE EWD ACROSS THE FOUR CORNERS
REGION AND INTO THE HIGH PLAINS SATURDAY EVENING. MODEL FORECASTS
DEVELOP THUNDERSTORMS ALONG A WELL-DEFINED DRYLINE DURING THE
EVENING FROM WRN OK SSWWD ACROSS NW TX INTO WCNTRL TX. FORECAST
SOUNDINGS SATURDAY EVENING ALONG THIS CORRIDOR SHOW MODERATE
INSTABILITY...STRONG DEEP LAYER SHEAR AND STEEP MID-LEVEL LAPSE
RATES WHICH SHOULD BE FAVORABLE FOR SUPERCELLS WITH LARGE HAIL.
SUPERCELLS SHOULD BE CAPABLE OF PRODUCING 2 INCH OR GREATER HAIL DUE
TO THE THERMODYNAMIC PROFILE. STRENGTHENING LOW-LEVEL SHEAR DURING
THE EVENING SHOULD ALSO RESULT IN A TORNADO THREAT AS WELL.

..BROYLES.. 04/13/2012

[Tony Gilbert]

Indeed.! And very rare for SPC to go straight to High Risk this early in the model evolution. There must be some certainty within the various model output.

Many UK chasers will be 'chomping at the bit' for a taste of this lot!
Whilst there is some certainty that a Moderate/ High risk will occur during April, we can never really be sure as to when. The dilemma for any early season UK storm chaser would be taking that gamble for this particular month. Hence the obvious advantages of living in the USA

[Krun2k]

Tony Gilbert, on 13 April 2012 - 07:22, said:

Indeed.! And very rare for SPC to go straight to High Risk this early in the model evolution. There must be some certainty within the various model output.

Many UK chasers will be 'chomping at the bit' for a taste of this lot!
Whilst there is some certainty that a Moderate/ High risk will occur during April, we can never really be sure as to when. The dilemma for any early season UK storm chaser would be taking that gamble for this particular month. Hence the obvious advantages of living in the USA

Tony, so this will likely stay in more southern areas like Kansas and Oklahoma? I couldn't get a read on that warning posted except that it'll be from Kansas and South as the most severe on Saturday. I'll be keeping an eye out but I'd really appreciate your opinion!!

Karen
Omaha Nebraska

BTW Tony, my Grandmother lived through the Late March 1913 tornado in Omaha which killed hundreds of people. SO April isn't out of the question for this area.

This post has been edited by Krun2k: 13 April 2012 - 07:43

[Ian Williams]

Krun2k, on 13 April 2012 - 07:40, said:

Tony, so this will likely stay in more southern areas like Kansas and Oklahoma? I couldn't get a read on that warning posted except that it'll be from Kansas and South as the most severe on Saturday. I'll be keeping an eye out but I'd really appreciate your opinion!!

Karen
Omaha Nebraska

BTW Tony, my Grandmother lived through the Late March 1913 tornado in Omaha which killed hundreds of people. SO April isn't out of the question for this area.

Hi Karen, Omaha is in the northern most moderate risk area, at this time. Best checking again later in the day for any subtle changes

This post has been edited by Ian Williams: 13 April 2012 - 08:44

[Bazmundo]

Given the moisture feed from the south with around 50kts of bulk DLS it's easy to see why they're being proactive with this one. SErn NE does looks to have some nasty storms going by both NAM and GFS, but the risk is greater further south. Quite significant differences in precip pattern between the NAM and GFS, but the potential looks to be agreed.

Shame I'm on a wedding shoot this Saturday raising funds for the chase, otherwise I'd be following this very closely. Best of luck to everyone in the Mid West, it's times like this when they need it most.

[Nathan Edwards]

I'll be away at a Wedding this Saturday so won't be around much to follow this. Certainly looks like a potentially big day, though usual caveats apply regarding overnight convection. The raw ingredients are there, but initiation pre dusk is still not a guarantee looking a the models. Of course, these models will not be picking up on boundaries left by overnight convection and I imagine these will be key as far as afternoon initiation goes. Would be definately worth keeping an eye out for residual outflow boundaries on the morning satellite imagery and picking a chase location based on that. Any cell that goes up in the warm sector has a good chance of being tornadic so nailing initiation seems to be the big challenge on Sat.

[Gone Fishing]

Hi Tony,


Some of us mad brits have made the trip over for this one so hopefully we can get some decent images for you. (It's Paul Sherman Here Btw Just cannot log on since the server change)

Flew in on Wednesday and played around with some of the Supercells around Amarillo that day, yesterday was a Total Bust along the Dryline in SW Kansas (Reminded me of a day last year in the same area when Cirrus and High Clouds Ruined Surface Heating)


Today sees us move back down towards Central Oklahoma for another possible Dryline day and tomorrow sees the last day of our 4 Day Trip before the Flight back on Sunday.


This is new ground for me as the other dozen or so High Risk's I have chased have never seen a 60% Hatched Box and even May 24th 2011 only had a 30% Hatched Box (Canton EF4 & Piedmont EF5 Storms)

I am hoping the dryline sets up further West tomorrow and does not Impact OK City or Wichita though the omens do not look good, stupid Storm Motions once again will be the concern for chasers and also having to cut the chase off to give assistance if we come across it.

Will keep you all updated and you can find our stream on Chasertv under the James Menzies car Icon.

[Ian Williams]

Gone Fishing, on 13 April 2012 - 14:23, said:

Hi Tony,


Some of us mad brits have made the trip over for this one so hopefully we can get some decent images for you. (It's Paul Sherman Here Btw Just cannot log on since the server change)

Flew in on Wednesday and played around with some of the Supercells around Amarillo that day, yesterday was a Total Bust along the Dryline in SW Kansas (Reminded me of a day last year in the same area when Cirrus and High Clouds Ruined Surface Heating)


Today sees us move back down towards Central Oklahoma for another possible Dryline day and tomorrow sees the last day of our 4 Day Trip before the Flight back on Sunday.


This is new ground for me as the other dozen or so High Risk's I have chased have never seen a 60% Hatched Box and even May 24th 2011 only had a 30% Hatched Box (Canton EF4 & Piedmont EF5 Storms)

I am hoping the dryline sets up further West tomorrow and does not Impact OK City or Wichita though the omens do not look good, stupid Storm Motions once again will be the concern for chasers and also having to cut the chase off to give assistance if we come across it.

Will keep you all updated and you can find our stream on Chasertv under the James Menzies car Icon.

Nice one Paul, cheers for the cam link i will be following proceedings tomorrow night. And i had a virtual bust last night too, which isn`t quite as frustrating as actually being out there of course, my target yesterday was Garden City SW KS but it all kicked off further north as you know. Are you not out there for your normal 6 week long haul this year? We are all out there Glyn, Chris Riley and myself and co, from 23rd May, so hopefully if your out there we may bump into each other again. Happy Hunting!!!!

[ChaserUK]

wow better change title of thread!! High Risk also NEB and IA now !!!

This post has been edited by ChaserUK: 13 April 2012 - 18:03

[Tony Gilbert]

Too early to make any precise target zone though Hutchinson Kansas looks good for now!

Karen you may be in line for severe weather by the early hrs of Sunday. Though this may change as the models are not reading correctly for me ATM?...Anyway hope you stay tuned and stay safe!

Nathen has made a good point regarding chase potential in that most of the severe weather aspect is likely to occur after dark. Not good for chasers!!

The corridor for activity is long and broad and I am glad to see that the SPC have come out on a limb to 'take the bit between the teeth' and issue a high risk at an early stage!
Opinion; recent years have seen a Slight Risk jump to Moderate/ High in no more than a 3 hr period. This is of no use to the public and may have contributed to unnecessary injury or even fatalities? I fully understand that the SPC's job is at best a thankless task but maybe the swing to better prep is the right direction, me thinks!

This post has been edited by Tony Gilbert: 13 April 2012 - 19:38

[ldavidcooke]

Hey All,

The language is new, this is an update to the older, "Probability of Sever Thunderstorms, with Hail, High Winds and localized flooding". (What I am waiting for are the introduction of multi-state evacuation orders next...) You would think that the states involved would either open below ground shelters or recommend evacuations based on predicted storm paths by now.

I believe this is first application of the new warning language, it is intended to make people take action on their own. Though if you are in the middle of the "kill zone" you would have to travel about 250-400 miles to move outside of the approaching front boundaries/convective plumes, which suggests if you are not out of the region by 9-10am local/cds you need to find an underground shelter. You should have 6-7 hours left to make final preparations, by 9am Sat.

(Est. Touch down potential is supposed to be nearer to 8-9pm. Experience suggests anytime after 2-3pm the chances are highest through roughly 1-2am, in this region. So you need to have at least 48hrs of food/water supplies in place by early Sat. morning, your radio turned on and at least one change of fresh batteries, one set each for the radio and another for the flashlight.)

[Krun2k]

Tony Gilbert, on 13 April 2012 - 19:36, said:

Too early to make any precise target zone though Hutchinson Kansas looks good for now!

Karen you may be in line for severe weather by the early hrs of Sunday. Though this may change as the models are not reading correctly for me ATM?...Anyway hope you stay tuned and stay safe!

Nathen has made a good point regarding chase potential in that most of the severe weather aspect is likely to occur after dark. Not good for chasers!!

The corridor for activity is long and broad and I am glad to see that the SPC have come out on a limb to 'take the bit between the teeth' and issue a high risk at an early stage!
Opinion; recent years have seen a Slight Risk jump to Moderate/ High in no more than a 3 hr period. This is of no use to the public and may have contributed to unnecessary injury or even fatalities? I fully understand that the SPC's job is at best a thankless task but maybe the swing to better prep is the right direction, me thinks!

Tony, Thanks, I'm glad to see it's an early morning event. Takes the choice of location to ride it out away from me. I'll be at home watching out the back door as usual.
Karen

[Sam Jowett]

Looking at this mornings model runs, I'd have said the Eastern half of the KS/NE border looks the best starting point for any chase. Helicity is stronger in this northern part of the high risk zone and arrives nearer to peak heating. The show in OK and S KS looks later and the best shear only overspreads the region after 1800 CDT, so I'd imagine there's greater change of the boundary layer decoupling and reduced potential for the full scope of the shear and helicity to be utilised. SPC seem to be less bullish with their language regarding the potential in the southern part of the risk zone now too... though of course it is still high! Stay safe out there folks... could be a rough ride tonight!

[Bazmundo]

I think the worst of this is going to be northeast KS and central to eastern NE, there still doesn't seem to be as much precip further south from models other than the GFS, though the RUC is starting to show isolated fast-movers in western OK on the dryline at 20z. I'd probably target Salina KS early on from around 18z onwards for slower moving storms with broader hods, then recheck from there if a dive south is possible going into dusk.

[ChaserUK]

Here we go! Bit earlier than I thought??

URGENT - IMMEDIATE BROADCAST REQUESTED
TORNADO WATCH NUMBER 165
NWS STORM PREDICTION CENTER NORMAN OK
1045 AM CDT SAT APR 14 2012

THE NWS STORM PREDICTION CENTER HAS ISSUED A
TORNADO WATCH FOR PORTIONS OF

CENTRAL KANSAS
NORTHWEST OKLAHOMA

EFFECTIVE THIS SATURDAY MORNING AND EVENING FROM 1045 AM UNTIL
600 PM CDT.

...THIS IS A PARTICULARLY DANGEROUS SITUATION...

DESTRUCTIVE TORNADOES...LARGE HAIL TO 4 INCHES IN DIAMETER...
THUNDERSTORM WIND GUSTS TO 80 MPH...AND DANGEROUS LIGHTNING ARE
POSSIBLE IN THESE AREAS.

THE TORNADO WATCH AREA IS APPROXIMATELY ALONG AND 85 STATUTE
MILES EAST AND WEST OF A LINE FROM 25 MILES EAST SOUTHEAST OF
GAGE OKLAHOMA TO 55 MILES NORTHWEST OF CONCORDIA KANSAS. FOR A
COMPLETE DEPICTION OF THE WATCH SEE THE ASSOCIATED WATCH OUTLINE
UPDATE (WOUS64 KWNS WOU5).

REMEMBER...A TORNADO WATCH MEANS CONDITIONS ARE FAVORABLE FOR
TORNADOES AND SEVERE THUNDERSTORMS IN AND CLOSE TO THE WATCH
AREA. PERSONS IN THESE AREAS SHOULD BE ON THE LOOKOUT FOR
THREATENING WEATHER CONDITIONS AND LISTEN FOR LATER STATEMENTS
AND POSSIBLE WARNINGS.

DISCUSSION...A CLUSTER OF THUNDERSTORMS IS RAPIDLY INCREASING OVER
SOUTHWEST KS AND SHOULD SPREAD ACROSS CENTRAL KS THROUGH THE
AFTERNOON. OTHER STORMS MAY DEVELOP SOUTHWARD INTO NORTHWEST OK IN
THE NEXT COUPLE OF HOURS. INITIAL STORMS MAY BE ELEVATED.
HOWEVER...SURFACE DESTABILIZATION WILL OCCUR AS LOW CLOUDS BURN
OFF...AIDING IN STORMS BECOMING SURFACE-BASED. VERY FAVORABLE
VERTICAL SHEAR PROFILES WILL PROMOTE A RISK OF TORNADIC SUPERCELLS
CAPABLE OF VERY LARGE HAIL AND DAMAGING WINDS. STRONG TORNADOES
WILL BE AN INCREASING RISK THROUGH THE AFTERNOON.

[ChaserUK]

BULLETIN - EAS ACTIVATION REQUESTED
TORNADO WARNING
NATIONAL WEATHER SERVICE HASTINGS NE
1209 PM CDT SAT APR 14 2012

THE NATIONAL WEATHER SERVICE IN HASTINGS HAS ISSUED A

* TORNADO WARNING FOR...
WESTERN JEWELL COUNTY IN NORTH CENTRAL KANSAS...
NORTHWESTERN MITCHELL COUNTY IN NORTH CENTRAL KANSAS...
NORTHEASTERN OSBORNE COUNTY IN NORTH CENTRAL KANSAS...
SOUTHEASTERN SMITH COUNTY IN NORTH CENTRAL KANSAS...

* UNTIL 1245 PM CDT

* AT 1204 PM CDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
SEVERE THUNDERSTORM CAPABLE OF PRODUCING A TORNADO. THIS DANGEROUS
STORM WAS LOCATED 5 MILES SOUTH OF OSBORNE...OR 30 MILES WEST OF
BELOIT...AND MOVING NORTHEAST AT 45 MPH.

* LOCATIONS IMPACTED INCLUDE...
DOWNS...CAWKER CITY...IONIA...ESBON...BURR OAK AND MANKATO.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

THIS TORNADO WARNING REPLACES THE SEVERE THUNDERSTORM WARNING THAT
WAS IN EFFECT FOR THE SAME AREA.

[Jason Smith]

Woŵ, you know something will hit the fan when sky have a chaser reporting for 5 mins on news. EF4-5 high probability with set up, stay safe chasers.

[Tony Gilbert]

Ironically the next 3 hrs is likely to produce numerous large tornado reports for OK and KS. Though particular attention is given to the cell now developed NW OK as per image which based on the HRRR model could produce quite a prolific dangerous sized tornado within the projected path. The HRRR whilst experimental is ingesting all the obs data as we speak and has made a real focus on this particular cell regarding shear parameters!

Attached thumbnail(s)

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This post has been edited by Tony Gilbert: 14 April 2012 - 20:28

[Ian Williams]

Tony, do you have any links to the HRRR model please.?

[ChaserUK]

looking at chasetv numerous tornadoes about to drop from those cells