Chase 2009 Day 6 Discussion

[Paul Sherman]

- 10% Which could be Upgraded :lol:

DAY 1 CONVECTIVE OUTLOOK

NWS STORM PREDICTION CENTER NORMAN OK

1244 AM CDT FRI MAY 01 2009

VALID 011200Z - 021200Z

...THERE IS A SLGT RISK OF SVR TSTMS ACROSS A LARGE PART OF THE SRN

PLNS EWD INTO THE MID-SOUTH AND OH/TN VLYS...

...SYNOPSIS...

UPR TROUGH WILL DEEPEN SLIGHTLY ACROSS THE MIDWEST...GREAT LAKES AND

NERN STATES ON FRIDAY AS THE HUDSON BAY VORTEX REPOSITIONS SWD. A

SEPARATE BELT OF MODEST FLOW WILL EXIST ACROSS THE SRN PLNS INTO THE

MID-ATLANTIC REGION. EMBEDDED CONVECTIVELY ENHANCED DISTURBANCES

WILL EXIST WITHIN THIS JET. NEXT MID-LVL SHORTWAVE TROUGH...NOW

OVER THE ERN PACIFIC BASIN...WILL QUICKLY TRANSLATE EWD...ARRIVING

INTO CA BY EARLY SATURDAY.

IN THE LWR LEVELS...SYNOPTIC CDFNT TIED TO THE AMPLIFYING NRN STREAM

UPR WAVE WILL SETTLE SEWD...REACHING NEW ENGLAND...THE OH VLY...AND

SRN PLNS STATES BY FRIDAY NIGHT. A MYRIAD OF PRE-FRONTAL OUTFLOW

BOUNDARIES WILL LIKELY EXIST THROUGHOUT THE OH/TN/LWR MS VLYS AND

SRN PLNS. A DRYLINE WILL MIX EWD INTO NWRN TX AND THE ERN EDWARDS

PLATEAU.

...SRN PLNS INTO THE MID-SOUTH...

SEVERAL TSTM CLUSTERS ARE EXPECTED TO BE ONGOING FRIDAY MORNING

ACROSS THE OZARKS AND ERN OK ALONG THE NOSE OF A VEERING LLJ.

STORMS MAY ALREADY BE PRODUCING LARGE HAIL AND GUSTY WINDS. AIR

MASS DOWNSTREAM ACROSS THE MID-SOUTH WILL LIKELY HEAT SIMILAR TO

THURSDAY AND MAY BE COMPARATIVELY MORE UNSTABLE OWING TO STEEPER

MID-LVL LAPSE RATES WITH MLCAPES OF 1500-2000 J/KG EXPECTED. THE

FLOW ALOFT WILL BE SOMEWHAT WEAK...WELL REMOVED FROM THE PRIMARY

TROUGH ACROSS THE MIDWEST. HOWEVER...CORRIDORS OF STRONGER FLOW MAY

EVOLVE WITH ANY MCV THAT MAY DEVELOP...AND GIVEN AT LEAST MODEST

BUOYANCY...MULTICELL STORMS MAY PRODUCE SPORADIC DMGG WIND AND LARGE

HAIL.

HIGHER SVR PROBABILITIES WILL DEVELOP UPSTREAM BY LATE FRIDAY AFTN

AND EVENING. TRAILING OUTFLOW FROM OVERNIGHT STORMS WILL LIKELY

STALL ACROSS SRN OK AND ADJOIN WITH A TRIPLE POINT OVER FAR SW

OK/WRN N TX. STRONG HEATING IN COMBINATION WITH MID-UPR 60S SFC DEW

POINTS AND 8-8.5 C/KM MID-LVL LAPSE RATES WILL CONTRIBUTE TO AN

EXTREME UNSTABLE ENVIRONMENT OVER SRN OK/NRN TX WITH MLCAPES OF

3000-4000 J/KG. AS SBCINH WEAKENS...INGREDIENTS WILL BE FAVORABLE

FOR RAPID TSTM INITIATION INVOF THE TRIPLE POINT AND POINTS EWD

ALONG/N OF THE OUTFLOW BOUNDARY. BULK SHEAR OF 30-35 KTS AND

EXTREME INSTABILITY WILL RESULT IN SUPERCELLS WITH VERY LARGE HAIL.

A FEW TORNADOES WILL BE POSSIBLE WITH MATURING DISCRETE CELLS ACROSS

EXTREME SWRN OK AND WRN N TX THROUGH EARLY EVENING. ANY SUPERCELL

SPLITS WILL MOVE NWD...POSSIBLY INTO CNTRL OK DURING THE EVE WITH A

LARGE HAIL THREAT.

WNWLY H5 FLOW OF 30-35 KTS AND PERSISTENT MOIST BOUNDARY LAYER

INFLOW DURING THE EVENING ALONG WITH GROWING COLD POOLS MAY LEAD TO

A FORWARD PROPAGATING MCS /BOW ECHO/ THAT DEVELOPS ACROSS SRN OK AND

N TX...WITH THE APEX FAVORING THE EVENTUAL RESTING PLACE OF THE

OUTFLOW BOUNDARY...PROBABLY INVOF THE RED RIVER FRIDAY EVENING.

DMGG WINDS AND LARGE HAIL WILL BE LIKELY. TAIL-END OF THE MCS MAY

CONTINUE TO BACKBUILD SEWD TOWARD I-20 AND MAINTAIN CYCLIC SUPERCELL

CHARACTER INTO LATE EVE WITH DMGG WINDS/LARGE HAIL AND ISOLD

TORNADOES.

ONCE THE FINAL LATITUDINAL PLACEMENTS OF THE AFOREMENTIONED

BOUNDARIES ARE BETTER KNOWN...PARTS OF THE REGION MAY NEED AN

UPGRADE TO A MDT RISK.

Going to be a Late One Tomorrow even after Chasing as Tornadoes could be occuring as we book into the Hotel after the Chase

Paul S

[MAF]

looking good Paul

Morning to you and the chase team :lol:

[MAF]

Latest update for status report #219

VALID 010625Z - 010740Z

THE SEVERE WEATHER THREAT CONTINUES ACROSS THE ENTIRE WATCH AREA.

WRN PORTIONS WW MAY BE CLEARED IN NEXT 1-2 HOURS GVIEN CURRENT

WEAKENING TRENDS WITH LONE REMAINING SUPERCELL IN CENTRAL OK.

[Nick F]

Yep, looks like it could go moderate - especially over NW/N-central TX. Looking at the models, Dryline triple point looks like being the focus for some possible tornadic supercells in a triangle of NW TX between Childress and Guthrie to Witchita Falls ... some big CAPE and strong helicity values modelled roughly in this area by WRF:

WRF Tds 00z Sat, showing dryline triple point with cold front over NW TX (as I've marked):

WRF SB/MUCAPE 00z Sat:

Some strong 0-1km and 0-3km SRH values in this general area

Certainly would head down to Wichita Falls or perhaps Childress and see what happens ... could be very productive.

[MAF]

latest radar for those areas Nick mentions

http://radar.weather.gov/radar.php?rid=fdr...111&loop=no

local forecasts for both Childress and WF could mean its going to need an executive decision as to which are to choose. :lol:

basically it may need a toss of a coin

[chionomaniac]

Morning all. I missed last nights chase but heard you bagged the only supercell. Well done.

It looks promising today with a compact area to focus on. I reckon that I would sit up in Vernon and wait to see what happens. Looks good road network there and hopefully bandwidth!

c

[Tony Gilbert]

A classic chase day with the potential for slow moving well defined tornadoes within a low shear high instability climate. I agree with Nick, this one could go moderate. Locating the triple will be key to success. I usually draw a line between the contrast of low to high dew points. Low to high temps can also be use here. TP can be recognised by studying this line to recognise the intersection of occlusion and cold front by a pressure drop and wind veer.

Classic chase day potentially. I would be getting to Witchita Fall by mid afternoon and then check the surface obs.

[MAF]

lots of info for the area here >>

http://www.srh.noaa.gov/oun/enhanced.php

[chionomaniac]

Latests obs (1009Z) show the dry line on the TX/NM border with the triple point near Clovis.

http://www.hpc.ncep.noaa.gov/sfc/lrgnamsfcwbg.gif

Some good differences in dewpoints there already though I am not too sure how nighttime affects this.

[Gorky]

Not had chance to look at the models today, but yesterday, I was tending towards Wichita Falls or perhaps even further south. Seems like the sort of setup where you could get adiscrete cell or two forming off the dryline bulge forecast down in TX. I think the triangular area bounded by Throckmorton, Graham and Breckenridge might be the place to be for intiation. Will update my thoughts at 5pm-ish :unsure:

Also, I'm sure we'll get an upgrade to the tor chances next update (to 10% hatched at least) and over a slightly larger area. Shear and Cape values are both suitable for strong tornadoes. Looks like it could be good day. Most models break out a few areas of precip this far south, but the only concern would be with a strongish cap which might limit the southern extent of the action and keep cells up near the triple point (as happened yesterday)

[Paul Sherman]

Going to get the troops ready to roll at about 11am and head for Lunch at Witchita Falls (Tx) and see how things are panning out from there, big concern about River Crossings today in the Tornado Area on two counts, firstly there are not many of them so finding a Supercell with good road options could be tough and secondly the Flood Options, Witchita Falls and the Red River has recieved over 6" of Rain this week and the River is already in Flood at the Moment.

We will do our best with what road options we have but I think The Storms have a greater Chance of dropping Tubes than yesterday.

Paul S

[MAF]

morning Paul, yes i was going to ask you about the rainfall situation out there. understand there is potential for lots off flooding.

[Tom Lynch]

looking good Paul

Morning to you and the chase team

and a good morning to you too.

Tom

[Paul Sherman]

morning Paul, yes i was going to ask you about the rainfall situation out there. understand there is potential for lots off flooding.

Yes Mick

It is a big concern, Will NOT Be taking any dirt roads today for obvious reasons, the ground down there is absolutely Saturated and Flash Flood Advisories have been going off all week for the Red River around the Witchita Falls area so certainly one to watch.

Paul S

[MAF]

well lets hope the weather plays the game and stays close to major routes today

its a glorious day here in C London and Trafalgar Square/Whitehall is packed with tourists/may day procession.

[Paul]

Paul (plus stalker) have uploaded today's briefing for you to view:

http://www.netweather.tv/index.cgi?action=...ase-video;sess=

[Louby]

Please don't tell me they are pants on Tom's head!!

[salts100]

what camera are you using for the shots you have got,

woud love to be out there with you guys all i do is wait for a good thunderstorm here in uk.

none as yet my way though

good pics any funnel clouds spotted yet.

all the best

[Ross B]

what camera are you using for the shots you have got,

woud love to be out there with you guys all i do is wait for a good thunderstorm here in uk.

none as yet my way though

good pics any funnel clouds spotted yet.

all the best

There is a video of a small funnel posted in the day 5 pictures topic i think.

Equipment topic: http://www.netweather.tv/forum/index.php?showtopic=54288 Should have peoples camera type

[Thermohaline Conveyor]

There is a video of a small funnel posted in the other topic i think.

Equipment topic: http://www.netweather.tv/forum/index.php?showtopic=54288 Should have peoples camera type

Lets get one like this today guys

http://www.youtube.com/watch?v=I2qf7Re0K8E...feature=related

I'll be following you again tonight. I trust you're doing Wichita Falls way.

[NL]

Moderate risk issued.

DAY 1 CONVECTIVE OUTLOOK

NWS STORM PREDICTION CENTER NORMAN OK

1131 AM CDT FRI MAY 01 2009

VALID 011630Z - 021200Z

...THERE IS A MDT RISK OF SVR TSTMS ACROSS PARTS OF SOUTHERN

OKLAHOMA AND PARTS OF NORTHERN TEXAS...

...THERE IS A SLGT RISK OF SVR TSTMS AROUND THE MODERATE FROM NWRN

TX TO THE LOWER OH VALLEY...

...THERE IS A SLGT RISK OF SVR TSTMS IN THE MID ATLANTIC REGION...

...SWRN OK INTO NRN TX...

MODERATE TO STRONG INSTABILITY AND /SBCAPE TO 4000 J PER KG/ AND

DEEP LAYER SHEAR 30-40 KT /SUFFICIENT FOR SUPERCELLS/ SHOULD

CONTINUE TO EVOLVE AHEAD OF THE ADVANCING COLD FRONT AND DRYLINE

FROM SWRN OK ACROSS THE RED RIVER VALLEY THIS AFTERNOON. THERE IS

NEARLY UNANIMOUS AGREEMENT ACROSS A BROAD RANGE OF AVAILABLE MODEL

GUIDANCE THAT SURFACE-BASED CONVECTION WILL INITIATE BY EARLY

EVENING NEAR FRONT/OUTFLOW/DRYLINE TRIPLE POINT AROUND SPS.

WHILE SYNOPTIC SCALE FORCING FOR ASCENT ACROSS THIS AREA OF INTEREST

IS EXPECTED TO BE WEAK IT WILL NOT NECESSARY BE HOSTILE TO STORM

DEVELOPMENT AS EVIDENCED IN THE NAM/GFS GUIDANCE AND RELATIVELY FLAT

MID-LEVEL HEIGHT PATTERN AND WLY 500MB WINDS AOB 30KT. THE EXISTENCE

OF STRONG LOW LEVEL FORCING ON THE MESOSCALE APPEARS TO AID

CONVECTIVE INITIATION IN A STRONGLY UNSTABLE AND SUFFICIENT SHEARED

ENVIRONMENT FOR STORMS TO QUICKLY ACQUIRE SUPERCELLULAR STRUCTURE.

MAGNITUDE OF CAPE WILL SUPPORT ROBUST UPDRAFTS AND MAY COMPENSATE

SOMEWHAT FOR LACK OF STRONG SYNOPTIC ASCENT WITH STROM MERGERS AND

COLD POOL DEVELOPMENT AIDING UPSCALE ORGANIZATION ACROSS NRN TX

THROUGH THE EVENING.

GIVEN THE STRONG SIGNAL FOR STORM DEVELOPMENT...AND DEGREE OF

DESTABILIZATION EXPECTED...A SMALL HIGHER PROBABILITY HAIL AREA HAS

BEEN ADDED TO THIS FORECAST. BASEBALL OR LARGER HAIL APPEARS QUITE

POSSIBLE WITH THESE STORMS...ESPECIALLY WITHIN A FEW HOURS OF

INITIATION. LACK OF STRONGER DEEP SHEAR AND WEAK LARGER SCALE

FORCING MAY LIMIT STORM COVERAGE. THIS FACTOR...AND GENERALLY

MARGINAL FORECAST HODOGRAPH STRUCTURE...INDICATE TORNADO POTENTIAL

MAY BE LIMITED IN TIME/SPACE. HOWEVER...MOIST BOUNDARY LAYER AND

LIKELIHOOD FOR SOME STORM-SCALE AND MESOSCALE ENHANCEMENT TO THE LOW

LEVEL WIND FIELD...MAY PLAY A ROLE IN FAVORING A TORNADIC SUPERCELL

OR TWO IN THIS REGIME.

EVENTUALLY...STRONG INSTABILITY AND RESULTANT COLD POOLS SHOULD

RESULT IN A SMALL MCS ACROSS THE RED RIVER/NWRN TX. THE POTENTIAL

FOR BOWING LINE SEGMENTS/SUPERCELLS WITH SEVERE HAIL AND WIND COULD

SHIFT ESEWD ACROSS FAR NRN TX/DFW THROUGH EVENING/LATE EVENING.

...NERN OK TO AR AND ACROSS LWR/MID MS VALLEY...

LEADING PORTION OF SYNOPTIC FRONTAL ZONE ACROSS NW AND NCNTRL OK IS

BEING REINFORCED BY ONGOING MCS NOW SPREADING ESEWD ACROSS NERN OK

AND THE OZARKS. MODEST CONTINUING INFLUX OF LOW LEVEL MOISTURE AND

MASS CONVERGENCE INTO THE MCS OUTFLOW/COLD POOL WILL MAINTAIN SOME

POTENTIAL FOR SEVERE HAIL AND WIND FROM NERN OK ACROSS AR THIS

AFTERNOON. POSSIBLE MCV EVOLVING FROM THIS ONGOING SYSTEM MAY

SUPPORT THE DEVELOPMENT AND PERSISTENCE OF ADDITIONAL STORMS ALONG

THE STALLING COLD FRONT...ALONG A LIT-MEM-BNA LINE...THROUGH LATE

TONIGHT. GENERALLY WEAKER DEEP LAYER FLOW ACROSS THIS ZONE SUGGESTS

THAT PRIMARY THREAT MAY BECOME EXCESSIVE RAIN. HOWEVER...A FEW

SEVERE STORMS ALSO APPEAR POSSIBLE IN THIS CORRIDOR THROUGH EARLY

SAT.

...LOWER/MID OH VALLEY...

A MARGINALLY UNSTABLE AIR MASS AHEAD OF THE SLOWLY ADVANCING COLD

FRONT ACROSS THIS AREA SHOULD LEAD TO AN INCREASE IN SHOWERS AND

THUNDERSTORMS THROUGH THIS AFTERNOON. DESPITE WEAK LAPSE

RATES...DEEP LAYER WLY FLOW MAY SUPPORT SOME ORGANIZATION TO THIS

ACTIVITY INTO THE EVENING HOURS WITH WIND AND MARGINALLY SEVERE HAIL

BEING THE PRIMARY HAZARDS.

...MID-ATLANTIC...

LOW AMPLITUDE SHORT WAVE TROUGH AND DIURNAL DESTABILIZATION WILL

CONTRIBUTE TO AN INCREASING CHANCE FOR THUNDERSTORM DEVELOPMENT

ALONG ADVANCING LEE/SYNOPTIC TROUGH THIS AFTERNOON.WARMING INTO THE

70S SHOULD YIELD SBCAPE AROUND 500-1000 J/KG. THIS INSTABILITY ALONG

WITH UNIDIRECTIONAL WLY WINDS AT 30-40 KT BETWEEN 850-300 MB SHOULD

BE SUFFICIENT FOR SPORADIC WIND DAMAGE WITH THE SQUALL LINE...BEFORE

IT PASSES OFF THE ATLANTIC SEABOARD THIS EVENING.

..CARBIN/GUYER.. 05/01/2009

[Ross B]

Lets get one like this today guys

http://www.youtube.com/watch?v=I2qf7Re0K8E...feature=related

I'll be following you again tonight. I trust you're doing Wichita Falls way.

I'm not out there until next friday... but i'll be watching again tonight.

They are heading Wichita Falls way yeah.

[Nick F]

GIVEN THE STRONG SIGNAL FOR STORM DEVELOPMENT...AND DEGREE OF

DESTABILIZATION EXPECTED...A SMALL HIGHER PROBABILITY HAIL AREA HAS

BEEN ADDED TO THIS FORECAST. BASEBALL OR LARGER HAIL APPEARS QUITE

POSSIBLE WITH THESE STORMS...ESPECIALLY WITHIN A FEW HOURS OF

INITIATION. LACK OF STRONGER DEEP SHEAR AND WEAK LARGER SCALE

FORCING MAY LIMIT STORM COVERAGE. THIS FACTOR...AND GENERALLY

MARGINAL FORECAST HODOGRAPH STRUCTURE...INDICATE TORNADO POTENTIAL

MAY BE LIMITED IN TIME/SPACE. HOWEVER...MOIST BOUNDARY LAYER AND

LIKELIHOOD FOR SOME STORM-SCALE AND MESOSCALE ENHANCEMENT TO THE LOW

LEVEL WIND FIELD...MAY PLAY A ROLE IN FAVORING A TORNADIC SUPERCELL

OR TWO IN THIS REGIME.

Maybe an idea for the team not to core punch today ... LOL.

Could be some Gorrilla Size Hail! Not suprised though, hourly meso charts already bullseyeing 4500 j/kg of SBCAPE just SW of Childress in the likely area if intiation in the Moderate risk area:

Bit of a cap to contend with though, so we will need to wait for UVV forcing from the dryline/triple point as it arrives later.

[MAF]

latest outlook for this afternoon

[salts100]

thanks for that guys. does your web feed have any sound at all would be great if there was.

how do you rate a nikon d80 with 18-135 lense as got one but want to know best cam for this type of photography

many thanks