Chase 2010 - Day 14 Discussion

[Paul Sherman]

Am expecting this to go High Risk in tomorrow's Day 1 Outlook. The only reason it is still a Moderate is due to the Elevated Hailstorms we are expecting tonight. Every Forum which is associated with Weather is predicting a Major Outbreak, all the deciding factors seem to have come together nicely for a Tornado Outbreak! Storm Motions will be very fast at 40-50mph in Kansas, Supercells will need time to Mature before they start dropping Tornadoes but expect quite a few to become Cyclic Supercells and one or two Strong Long Tracked High EF Numbers to occur. Further down the Dryline Storms will be more discrete and will move away from favourable conditions quite quickly so the trick on these will be to get on them early before they die off.

Current Chase Target is Enid to Wichita but this could all change if things change overnight.

From the SPC

DRYLINE PERPENDICULAR DEEP LAYER WIND VECTORS...WARM/MOIST SECTOR

MLCAPE VALUES OF 2000-3500 J/KG...AND EFFECTIVE SHEAR OF 50-70 KT WILL SUPPORT DISCRETE SUPERCELLS WITH THE POSSIBILITY OF VERY LARGE

HAIL. AS LOW LEVEL/NEAR-1 KM FLOW RE-INTENSIFIES DURING THE EARLY

EVENING HOURS...FORECAST SOUNDINGS ALSO REFLECT 300-400 M2/S2 OF 0-1 KM/EFFECTIVE SRH AHEAD OF THE DRYLINE...WHICH SUPPORTS THE POSSIBILITY OF SOME STRONG TORNADOES...PARTICULARLY FROM THE OK PORTION OF I-40/44 INTO SOUTH CENTRAL KS EITHER SIDE OF I-35/135.

Paul S

[AudMun]

Stay safe guys! By hell have fun but be careful. I'm jealous as hell!

Stewart

[Gorky]

I've parked up in South Haven, KS (right on the OK border) for the night with the current intention on waiting to see what sort of outflow boundaries get set up tomorrow. If we have one straddling the dryling bulge, I'll play that. If not, I'll head further north and then wait for initiation around Wichita.

If we get some storms passing through tonight, I have uninterrupted view to the SW so should be able to get some lightning shots!

[Roger J Smith]

This situation looks complicated. Rather cool moist air at surface all over OK and KS tonight will perhaps not break down on Monday and it's possible that the best severe storms will be in southwest OK moving towards OKC as a warm sector may develop rather gradually. I imagine there will be heavy storms in KS but they may be elevated above low-level cloud ceilings with temps only reaching 65 F with 62 F dew points ahead of the tropical warm front that may get as far north as OKC to MLC. I expect rather sluggish development of a true dry line as moist air has pushed west into eastern NM and the latest 00z model run shows a trailing wave in the low complex near Pueblo CO tomorrow evening. Anyway, these factors may become clearer in the morning, but that's how I see it developing. Tornadic storm potential does appear fairly high but may be further south than current targets. However, it could also develop this way and then have a second area of tornadic storms in western KS by late afternoon. I think eastern KS is going to stay under the lid of low-level warm frontal cloud to after sunset and then get severe storms at night.

[Nick F]

HIGH RISK today over E OK/SE KS.

http://www.spc.noaa.gov/products/outlook/day1otlk.html

Strong wording from SPC:

...REGIONAL TORNADO OUTBREAK AND LONG-TRACK STRONG TO VIOLENT

TORNADOES BECOMING LIKELY IN ERN OK AND SE KS FROM LATE THIS

AFTERNOON INTO THE EVENING...

This looks like turning into a dangerous situation later today/overnight for these areas, and unfortunately there could be an EF5 tornado somewhere, lets hope it avoids cities like OK City or Tulsa and stays out over open country. Please take great care team 2, especially as the chase terrain of this area turns wooded and hilly east of the I-35 towards Tulsa and Independence/Coffeyville from experience of being in those areas. I would initially target just NE of OK City, along the I-44 - perhaps Chandler. This area is within an environment of impressive 0-3km SR Helicity values and also large amounts of CAPE developing as moisture surges north behind warm front lifting north.

Storms may intially develop west of I-35 along approaching dryline, but best wind fields look to be 50-100 miles further east of dry-line where storms will quickly move into. Ideally on a high risk day you want to be downwind of storms that develop as they could quickly turn HP with rain wrapped strong tornadoes, but these storms look to have fast motions and maybe difficult to catch up with the poorer road options east of the I-35, so will be a gamble whether to follow or let them come towards you.

Storms may initiate over Norman/OK City area where the team are staying, as the dry-line approaches from the west, lets hope we don't see another tornado hitting the OK City like the EF5 that struck Moore just up the road in 1999

[NL]

The NWS (SPC) have issued a PUBLIC SEVERE WEATHER OUTLOOK in the last few minutes.

239

WOUS40 KWNS 101015

PWOSPC

ARZ000-KSZ000-MOZ000-OKZ000-101800-

PUBLIC SEVERE WEATHER OUTLOOK

NWS STORM PREDICTION CENTER NORMAN OK

0515 AM CDT MON MAY 10 2010

...SEVERE THUNDERSTORMS EXPECTED OVER PARTS OF THE CENTRAL AND

SOUTHERN PLAINS THIS AFTERNOON AND TONIGHT...

THE NWS STORM PREDICTION CENTER IN NORMAN OK IS FORECASTING THE

DEVELOPMENT OF A FEW STRONG...LONG-TRACK TORNADOES...LARGE HAIL AND

DAMAGING WINDS OVER PARTS OF THE CENTRAL AND SOUTHERN PLAINS THIS

AFTERNOON AND TONIGHT.

THE AREAS MOST LIKELY TO EXPERIENCE THIS ACTIVITY INCLUDE

EXTREME NORTHWEST ARKANSAS

CENTRAL AND EASTERN KANSAS

PARTS OF WESTERN MISSOURI

CENTRAL AND EASTERN OKLAHOMA

ELSEWHERE...SEVERE STORMS ARE ALSO POSSIBLE FROM SOUTHERN NEBRASKA

TO THE MIDDLE MISSISSIPPI VALLEY AND SOUTHWARD TO PARTS OF TEXAS.

A STRONG STORM SYSTEM TRACKING NORTHEASTWARD ACROSS KANSAS AND

OKLAHOMA THIS AFTERNOON AND EVENING...REACHING THE MIDDLE

MISSISSIPPI VALLEY LATER TONIGHT...WILL SUPPORT THE DEVELOPMENT OF

SEVERE THUNDERSTORMS THIS AFTERNOON INTO TONIGHT ACROSS PARTS OF

CENTRAL KANSAS AND OKLAHOMA TO WESTERN MISSOURI AND NORTHWEST

ARKANSAS. STRONG SOUTHERLY LOW LEVEL WINDS WILL SUPPORT A CONTINUED

NORTHWARD TRANSPORT OF MOISTURE THROUGH THE SOUTHERN AND CENTRAL

PLAINS INTO THE OZARKS TO MIDDLE MISSISSIPPI VALLEY. THIS MOISTURE

COMBINED WITH SURFACE HEATING ACROSS WESTERN OKLAHOMA INTO SOUTHWEST

KANSAS TODAY WILL CONTRIBUTE TO A VERY UNSTABLE AIR MASS BY LATE

AFTERNOON. THE ARRIVAL OF STRONG SOUTHWESTERLY MIDDLE LEVEL WINDS

ATOP THE SOUTHERLY WINDS NEAR THE SURFACE WILL RESULT IN FAVORABLE

CONDITIONS FOR FAST MOVING SEVERE STORMS PRODUCING A FEW STRONG...

LONG-TRACK TORNADOES...LARGE HAIL AND DAMAGING WINDS BEGINNING

ACROSS CENTRAL PARTS OF KANSAS AND OKLAHOMA IN THE LATE AFTERNOON.

ATMOSPHERIC CONDITIONS WILL REMAIN FAVORABLE FOR THESE STRONG TO

SEVERE STORMS TO SPREAD NEWD INTO PARTS OF MISSOURI AND NORTHWEST

ARKANSAS TONIGHT.

STATE AND LOCAL EMERGENCY MANAGERS ARE MONITORING THIS POTENTIALLY

VERY DANGEROUS SITUATION. THOSE IN THE THREATENED AREA ARE URGED TO

REVIEW SEVERE WEATHER SAFETY RULES AND TO LISTEN TO

RADIO...TELEVISION...AND NOAA WEATHER RADIO FOR POSSIBLE

WATCHES...WARNINGS...AND STATEMENTS LATER TODAY.

[toggerob]

Just been catching up on this upcoming weather event for tonight. Oklahoma City and Tulsa look right in the firing line for flanking storms in the early afternoon along with long-tracking (possible F4/5 Tornadoes) through the evening.

One out of OK. the map looks generally sparse, with only occasional settlements alongside the highways aswell as a few National Parks going into ARK. However with never having been stateside myself distances are hard to distinguish when looking at the states.

I'd vouch for staying within the dry-line and observing on the flanks rather than getting "in" on the action with this system, trying to chase this through possible Debris fields would be impossible and staying outside the Supercell, but within observational distance, is the easiest way of not only covering distance but making sure a Secondary TN doesn't come down right over your head.

I'll try and keep updates on both here and UKWW whenever any informative information comes through later on into this evening.

[Gorky]

Morning all!

Looking at the models this morning, the NAM is keeping the large CAPE values south of where I am in SC Kansas. I suspect due to concerns over morning cloud cover. It also shows what appears to be initiation in this area much earlier than further south where it struggle to break the cap on OK until late on. I imagine there will be a storm up here capable of dropping tornadoes but if they do, it won't take long for them to move out of a favourable area and maybe become slightly elevated. The NAM really struggles to light things up further south until the storms are well past I35. Hopefully, this is due to the fact that the model will not be able to take into account residual boundaries from yesterdays chase and these will act as focal points for initiation further south.

Other models vary. The GFS is much nicer, with slightly better moisture return, shows initiation further down into ok within daylight hours, and has a wicked dryline bulge at 0z on the OK, KS border. The WRF 4km model struggles with initiation in OK also, but shows nice returns from a cell originating in north OK moving quickly into south KS.

Given all this, I am more than happy to stay in my current location. I doubt I will probably need to move much from this area for a good portion of the day as almost all areas in target are within 2 hours drive.

[Nick F]

09z RUC has some very large CAPE values (up to 4500 j/kg SBCAPE) in an axis pretty much following the I-35 corridor in Oklahoma at 21z (3pm CDT), it also starts to break out convective ppn by then around OK City,

very good SR Helicity values just ahead of dryline approaching I-35 from west:

Could well see storms intiate along I-35 corridor, and to the west as dry line moves in, where to target not so simple, but ideally need good road options E and NE to follow the storms.

One word of warning, that they seem to be banging on about over on stormtrack forum is the limited exits on the I-44 NE from OK City to Tulsa and also abundance of roadworks around Tulsa, which could cause some problems with jams and escape options should chasers get munched. Road options tend to get sparser towards NE Oklahoma and into SE Kansas too amongst the trees and hills, so will be rather challenging for chasers today, unless they play the wild card and target lone supercells that may develop further south along dry-line over south-central/SW Oklahoma into NW/N Texas - where kinematics are less favourable, but may spawn tornadoes.

[Harry]

I learned so much last week, words fail me. However, I am not sure I've learned as much as to second guess where the Shermanator will head today I'm quite a stubborn fish so will have a punt anyway

Paul S mentioned last week (before the charts became more specific I hasten to add) that a target of the NE side of LP system would give the least chance of a bust! This was certainly true of the Kansas supercell on Thursday, which was spectacular and was the only organised, tornadic supercell. Furthermore, on Thursday and indeed for the duration of Tour 1, the dry line produced nothing and on all occasions Paul S was spot on to avoid it.

Today however does not seem to be the case - the temp/due point spread appear to be almost dream material, of an approx 88F/75F spread on a line through SW to NE OK (which would appear to be the dryline - I'm only looking at GFS charts on NW), which on the W has dew points of below 32F or below, while to the East of 70F+.

The roads in OK, particularly the I35 appeared to have areas of road works at various points, and has been mentioned previously, more extensively across NE OK around the Tulsa area. Also the further East you head in OK becomes almmost like Misery (Missouri), hilly and heavily tree-lined in places. Not only is it immensely frustrating not being able to see what's coming at you, but on a day like today, very dangerous.

I imagine Paul will position either S of Norman/OK City to intercept what fires up on the dryline, or will head towards what became chase heaven for Tour 1, Kansas where there appears to be less convective inhibition and an equally strong tornado risk.....

I can't wait to see the Chase Briefing, with hopefully some funny addages from Tom also

Good luck guys - hope you see some awesome weather today And stay safe!

:lol: :lol:

Edited May 10, 2010 by Harry

[Gorky]

RUC is very bullish that the OK CAP will be broken at 0z today. Prior to that, it has a rogue cell on it's own SW of OKC firing off the dryline, but at 0z, the entire line goes up through to Kansas. This is now east of OKC and into slightly poorer chase country until you get south of I40. The RUC is showing much higher CAPE values than the other models at the moment, which is why they are holding off somewhat.

[Nick F]

Yes some insane SBCAPE values on 12z RUC over central OK:

The model breaks out convective precip just east of I-35 from OK City up to Kansas border:

Big CAPE overlapped by strong 0-3km SR Helicity to rotate storms:

Dryline bulge on I-35 north of OK City up to KS border?:

Based on this I would make a final target of Perry, OK - just off the I-35. Hopeful that higher dew points will surge north into this area ahead of dry line.

[Paul Sherman]

Lol Harry

No funny adages from Tom in the Chase Briefing today, all seriousness :lol: :lol:

I am still going with Blackwell / Tonkawa which is East of Enid (Ok) as I want to be 50 or so Miles East of the Dryline Bulge.When Storms form this will also take me away from the Tulsa area. Expect Storms to start dropping Nado's a few hours after they Initiate and not straight away. Window of Opportunity todays looks to be 5-8pm. If you get behind the Line today you might as well Give Up! 50-60mph Storm Motions to the ENE Are going to be brutal, it's a day of letting the Storms come to you.

I still very much like the chances of something kicking off further South and with storm speeds of 25-30mph this is still appealing and it is why I stopped short of going too far North. If something can kick further South and West then OK City could be in the firing line. It's all about percentages on this one, Percentage chances of a Tornado in the High Risk much higher for daytime Nado's but still good further South before Sunset!

Stay safe everyone!

Paul S

[Harry]

Cafe Del Mar, Mr Blue Sky, Insomnia, at 200dB, sitting under 4000+ CAPE and erupting supercells! Heaven!

Wouldn't play Victims until you're back at the hotel safe and sound and reviewing the footage though, HA :lol:

Edited May 10, 2010 by Harry

[Gorky]

Wow... Cape values approaching 6000 in central OK?? It's no wonder that's forecast to explode down there

[Harry]

Wow... Cape values approaching 6000 in central OK?? It's no wonder that's forecast to explode down there

S, S, S, S, SIX THOUSAND!!! :lol: :lol:

I was lucky enough to see what 3200 did - trying to comprehend what twice that would do.... (see pic - what my brain comes up with, lol)

All batteries charged lads and lasses, this could be a day we'll be talking about in 2020 (and beyond)

EDIT - For those of you in the US curious what the convective status is locally today - at peak heating (4pm, lol) I see a Cu the size of a pin cushion, amongst a colossal stratus mess - closest I've seen to CAPE was a Scottish Widow advert on TV, lol

Edited May 10, 2010 by Harry

[Gorky]

14z RUC pushing things a touch west, now the right side of I35 as far as terrain goes... (also pushing cape values close to 7000 now! :o)

Edited May 10, 2010 by Gorky

[Harry]

7000? :o

Best of luck to the cap then, lol!!

[icbinb]

Its gonna be a late night watching this one, but I wouldn't miss it for the world! 7000 is insane. Good luck tonight and don't go down too many dirt roads!

[NL]

First of many Meso-discussion.

420

ACUS11 KWNS 101538

SWOMCD

SPC MCD 101537

OKZ000-KSZ000-COZ000-101730-

MESOSCALE DISCUSSION 0506

NWS STORM PREDICTION CENTER NORMAN OK

1037 AM CDT MON MAY 10 2010

AREAS AFFECTED...PARTS OF EXTREME ERN CO...WRN KS INTO NW OK

CONCERNING...SEVERE POTENTIAL...WATCH LIKELY

VALID 101537Z - 101730Z

TRENDS ARE BEING MONITORED FOR AN INCREASING SEVERE THREAT AND THE

POSSIBILITY OF A WW...WHICH SEEMS LIKELY TO BE NEEDED AROUND 17-18Z.

LATEST OBSERVATIONAL DATA AND RUC GUIDANCE INDICATE THAT A 90+ KT

CYCLONIC 500 MB JET STREAK IS ALREADY IN THE PROCESS OF NOSING EAST

OF THE SOUTHERN ROCKIES INTO/THROUGH THE TEXAS PANHANDLE REGION.

THIS IS EXPECTED TO BE ACCOMPANIED BY STRENGTHENING MID/UPPER

FORCING FOR UPWARD VERTICAL MOTION SPREADING EAST OF THE ROCKIES

THROUGH THE CENTRAL HIGH PLAINS BETWEEN NOW AND EARLY

AFTERNOON...WHICH LIKELY WILL CONTRIBUTE TO STEEPENING LAPSE RATES

AND MODERATELY STRONG CAPE AS SURFACE HEATING PROGRESSES. THE

DEVELOPING DRY LINE NEAR A DEEP SURFACE LOW PROGGED TO MIGRATE

SOUTHEASTWARD OUT OF EAST CENTRAL COLORADO INTO SOUTHWEST KANSAS IS

EXPECTED TO BECOME THE FOCUS FOR STRONG DESTABILIZATION ...AND STORM

INITIATION...POSSIBLY AS EARLY AS THE 17-19Z TIME FRAME. DEEP LAYER

SHEAR IS ALREADY MORE THAN SUFFICIENT FOR SUPERCELLS...AND THOUGH

SOUTHERLY LOW-LEVEL FLOW FIELDS MAY REMAIN SOMEWHAT

MODEST...CLOCKWISE LOW-LEVEL HODOGRAPH CURVATURE/ INCREASING AMBIENT

VERTICAL VORTICITY AND BOUNDARY LAYER DESTABILIZATION WILL PROBABLY

BECOME CONDUCIVE FOR TORNADOES...IN ADDITION TO LARGE HAIL.

[user700]

We are all set for the high risk today!

we are atm going north on i35 to Perry Oklahoma. Then check the latest weather data.

Danny

[Paul]

Paul has put a video briefing together for today with info on the initial target, problems the team may encounter and his general thinking for today:

http://www.netweather.tv/index.cgi?action=storm-chase-highlights;sess=

[Nick F]

1630z SPC update:

DAY 1 CONVECTIVE OUTLOOK

NWS STORM PREDICTION CENTER NORMAN OK

1114 AM CDT MON MAY 10 2010

VALID 101630Z - 111200Z

...THERE IS A HIGH RISK OF SVR TSTMS OVER PORTIONS OF SOUTH

CENTRAL/SOUTHEAST KS...AND CENTRAL/NORTHEAST OK THIS AFTERNOON AND

EVENING...

...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 AND POTENTIALLY 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...

A POWERFUL AND PROGRESSIVE SHORTWAVE TROUGH IS TRACKING RAPIDLY

EASTWARD ACROSS CO/NM THIS MORNING...AND WILL EMERGE INTO THE HIGH

PLAINS BY LATE AFTERNOON. AHEAD OF THIS TROUGH...A BROAD AREA OF

STRONG SOUTHERLY LOW LEVEL WINDS IS TRANSPORTING GULF MOISTURE

QUICKLY NORTHWARD WITH MID 60S SURFACE DEWPOINTS NOW AS FAR NORTH AS

SOUTHERN OK. LOW CLOUDS ARE ALSO ERODING ACROSS OK WHICH WILL

RESULT IN A VERY POTENT SEVERE WEATHER SETUP LATER THIS AFTERNOON.

VIRTUALLY ALL MODEL GUIDANCE IS CONSISTENT IN FORECASTING THE

POTENTIAL FOR A REGIONAL TORNADO AND SEVERE WEATHER OUTBREAK OVER

PORTIONS OF KS/OK.

...SOUTHWEST KS...

INITIAL DEVELOPMENT WILL LIKELY OCCUR EARLY THIS AFTERNOON ALONG THE

DRYLINE OVER SOUTHWEST KS. LOW CLOUDS ARE ERODING FROM THE WEST IN

THIS AREA...LEADING TO A NARROW AXIS OF MODERATE INSTABILITY. LARGE

SCALE FORCING FOR UPWARD MOTION WILL ARRIVE IN THIS AREA

FIRST...WHERE THE CAPPING INVERSION SHOULD BE WEAK. WIND PROFILES

SUGGEST THE POTENTIAL FOR DISCRETE SUPERCELLS CAPABLE OF LARGE HAIL

AND TORNADOES. LONGEVITY OF THIS ACTIVITY IS UNCERTAIN AND DEPENDS

ON SPEED OF DESTABILIZATION FARTHER EAST INTO CENTRAL KS.

...SOUTHERN KS/NORTHERN AND CENTRAL OK...

THE PRIMARY CONVECTIVE DEVELOPMENT TODAY IS LIKELY TO BEGIN AROUND

21Z IN NORTH CENTRAL OR POTENTIALLY NORTHWEST OK ALONG THE DRYLINE.

THIS WILL ALSO BE NEAR THE TRIPLE POINT INTERSECTION OF THE DRYLINE

AND RETREATING WARM FRONT. STORMS IN THIS AREA WILL BE IN AN

ENVIRONMENT CHARACTERIZED BY VERY FAVORABLE DEEP LAYER /EFFECTIVE

SHEAR OF 50-75 KNOTS/ AND LOW LEVEL VERTICAL SHEAR /EFFECTIVE SRH OF

250-350 M2/S2/...ALONG WITH AMPLE MOISTURE /DEWPOINTS IN THE UPPER

60S/ AND CAPE /RELATIVELY UNCAPPED MLCAPE OVER 3000 J/KG/. STORMS

SHOULD BECOME RAPIDLY SUPERCELLULAR AND RACE EAST-NORTHEASTWARD

ACROSS SOUTHERN KS AND NORTHERN OK THROUGH THE AFTERNOON AND

EVENING. PARAMETERS INDICATE A HIGH POTENTIAL FOR INTENSE

SUPERCELLS CAPABLE OF STRONG AND EVEN LONG-TRACK TORNADOES. VERY

LARGE HAIL AND DAMAGING WINDS ALSO APPEAR LIKELY WITH THE STRONGEST

CELLS.

THE EXTENT OF DEVELOPMENT SOUTHWARD ALONG THE DRYLINE REMAINS A

QUESTION. SOME OF THE 12Z MODEL RUNS ARE MORE AGGRESSIVE IN

SOUTHWARD DEVELOPMENT...SUGGESTING WIDESPREAD COVERAGE OF SEVERE

STORMS COULD BE AS FAR SOUTH AS I-40. HOWEVER...HIGHEST CONFIDENCE

REMAINS OVER THE NORTHERN HALF OF THE HIGH RISK AREA. ANY STORM

THAT FORMS ALONG THE DRYLINE IN OK TODAY WILL POSE A THREAT OF

STRONG TORNADOES AND VERY LARGE HAIL.

SURFACE DRYLINE EXTENDS SOUTHWARD INTO CENTRAL TX...AND MAY PROVIDE

THE FOCUS FOR ISOLATED SEVERE STORMS LATE THIS AFTERNOON AND EARLY

EVENING. LACK OF SUFFICIENT LARGE SCALE FORCING AND A RATHER STRONG

CAPPING INVERSION SUGGEST THAT AREAL COVERAGE OF STORMS WILL BE

QUITE SPARSE.

..HART/SMITH.. 05/10/2010

[ian cameron]

Stopped briefly across the road from the Vortex2 Armada.

All the guys have just gone over and chatted to them, Jo has some pictures with Sean Casey and got a tour of the Tiv!

That guy is seriously nice!

Paul S

[Gorky]

I'm sat in Medford at the moment. Great roads East/West and North/South with amazing views. Very flat, gridded roads albeit a lot of them mud. The 12z WRF looks good for this area.

(time sensitive)