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Uncle Slayton
04-16-2013, 10:35 AM
SPC has trimmed the slight risk for today pretty substantially. OK is no longer included.

This is due to the thick, low hanging clouds we have around at this time that are aiding in the cooler temperatures.

Yeah, this has me bummed. I hope it doesn't take the wind out of the sails of tomorrow's outbreak. Although, I have a sneaking suspicion, to modify Venture's analogy slightly, we may be in for just some crappy tasting water tomorrow rather than a good pot of stew, or even (were I to dare hope), a hot pot of chili.

s00nr1
04-16-2013, 10:38 AM
12Z GFS prog for 00Z Thurs (7pm Wed). Yikes.


http://68.226.77.253/skewts/GFS-test/036/SKT_GFS__KOUN.png

venture
04-16-2013, 10:39 AM
Okay so I decided to show both NAM and GFS in this so that way everyone knows what is out there right now.

First off, Today. Slight risk is gone over Western Oklahoma. Something I completely agree with. Cap is too strong, we are socked in with clouds, and there just isn't any instability in that area. Might still see some storms late tonight and those could have some hail with them.

This morning's upper air sounding from Norman.
http://climate.cod.edu/data/raob/KOUN/skewt/KOUN.skewt.20130416.12.gif

Wednesday

As I've said many times already, higher end severe weather days are forecasts done based on all the conditions coming together perfectly. If one fly gets in the ointment, then you are liable to completely bust. So what are our flies for tomorrow?



Warm front doesn't proceed as far north as forecast.
Cold front moves in faster Wednesday than forecast.
Clouds - remember, bright clear sunny skies is NOT a positive if you don't want storms.
Early Convection - either on going Wednesday morning or storms fire too quickly late in the morning or early afternoon.


I don't envy SPC on trying to nail this one for tomorrow. So many variables in play and this has a feel that some of those factors mentioned above are probably going to happen. The other thing I don't care for is that now less than 24 hours to go, NAM and GFS are still separate. I like getting the domestic models together this close to an event, but maybe NAM is on to something. Regardless, the WPC has continued to favor GFS/UKMET for tomorrow. So what happens with NAM?

http://www.weatherspotlight.com/screencap/outlooks/20130417-3nam.png

This is at 7PM. Front never makes it all the way through NW OK so it starts coming back as a cold front at this time. Dryline sets up in SW OK. Instability is pretty good along/south of I-44. I highlighted the area that has the best chance for severe weather tomorrow, which is pretty close to the existing moderate risk. Forecast sounding over Norman still highlights a very favorable environment for severe weather in Central OK with the possibility for some strong tornadoes. We'll just have to see how the limiting factors could come into play.

http://beta.wxcaster.com/skewts/NAM-test/036/SKT_NAM__koun.png

SPC also has a index called "Significant Tornado" to calculate the potential for strong tornadoes. Here is that from NAM...

http://climate.cod.edu/data/forecast/NAM/12/SGP/namSGP_con_stp_036.gif

Finally the Supercell Composite Index, also from SPC, shows the potential for storms to take on supercell characteristics.

http://climate.cod.edu/data/forecast/NAM/12/SGP/namSGP_con_scp_036.gif

Now for the GFS side.

Don't have the custom map on this one since the 12Z data is in my app yet to draw it up. However, here are some snap shots of things to look at...

This is dewpoint and surface winds. You can see dryline back along OK/TX border and front is waaaay up into KS. Not sure how likely the front will go that far north, so we need to probably go a bit more realistic and put it closer to the OK/KS border.

http://climate.cod.edu/data/forecast/GFS/12/SP/gfsSP_0_30mbdewp_36.gif

Looking at CAPE values shows a very unstable atmosphere over Western OK along the dryline.

http://climate.cod.edu/data/forecast/GFS/12/SP/gfsSP_0_cape_36.gif

Finally the forecast sounding which is loaded for a severe weather outbreak type of day.

http://beta.wxcaster.com/skewts/GFS-test/036/SKT_GFS__KOUN.png

So looking at it all it is one of those days that can be very very big. However, if one of those 4 issues creep in it can throw the entire forecast off. Such is the case on these potential big days.

venture
04-16-2013, 11:31 AM
SPC updated the moderate risk for tomorrow. Skinnier than before and pretty much is the I-44 corridor.

http://www.spc.noaa.gov/products/outlook/day2otlk_1730.gif

http://www.spc.noaa.gov/products/outlook/day2probotlk_1730_any.gif

DAY 2 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1227 PM CDT TUE APR 16 2013

VALID 171200Z - 181200Z

...THERE IS A MDT RISK OF SVR TSTMS FOR FAR NWRN TX/SERN KS/SWRN
MO...SW TO NE OK...

...THERE IS A SLGT RISK OF SVR TSTMS FROM THE SRN PLAINS TO THE
MID-MS VALLEY...

...SYNOPSIS...
AN AMPLIFIED UPPER-LEVEL TROUGH OVER THE WRN CONUS WILL SHIFT EWD
STRETCHING FROM THE NRN PLAINS TO THE SOUTHWEST BY EARLY THU. A
VIGOROUS SHORTWAVE IMPULSE EMBEDDED WITHIN THE TROUGH SHOULD REACH
THE CNTRL HIGH PLAINS WED NIGHT WITH AN ATTENDANT MID-LEVEL SPEED
MAX EJECTING ACROSS THE CNTRL/SRN PLAINS. AT THE SURFACE...GUIDANCE
CONTINUES TO DEPICT SUBSTANTIAL DIFFERENCES WITH THE EVOLUTION OF AN
OSCILLATING FRONT AND ASSOCIATED CYCLOGENESIS OVER THE CNTRL CONUS.
AVERAGE CONFIDENCE EXISTS IN DRYLINE POSITION EXPECTED TO REACH
PARTS OF NWRN TX TO THE EDWARDS PLATEAU ON WED AFTERNOON.

...SRN PLAINS TO THE MID-MS VALLEY...
RELATIVELY MESSY SEVERE WEATHER SCENARIO IS EXPECTED WITH THE
AFOREMENTIONED SPREAD IN GUIDANCE BEING QUITE PRONOUNCED...WHICH
RENDERS LOW CONFIDENCE IN MAKING ANY SUBSTANTIAL CHANGES TO HIGHER
SEVERE PROBABILITIES ATTM. WILL DEFER TO LATER OUTLOOKS WHERE
OBSERVATIONS WILL PLAY A LARGER ROLE IN ADJUSTMENT TO THE MODERATE
RISK.

SIGNIFICANT LARGE-SCALE DIFFLUENCE/MID-LEVEL HEIGHT FALLS WILL
OVERSPREAD THE CNTRL CONUS ACROSS A RICH LOW-LEVEL MOISTURE PLUME.
THIS WILL ULTIMATELY YIELD A CONSIDERABLE AMOUNT OF CONVECTION ALONG
AND N OF THE SURFACE FRONTAL ZONE...MAINLY WED EVENING THROUGH THU
MORNING. GUIDANCE DIFFERS GREATLY ON PLACEMENT/TIMING OF CONVECTION
PRIOR TO PEAK HEATING ALONG THE FRONTAL CORRIDOR...WHICH MAY
MITIGATE MORE ROBUST NWD DESTABILIZATION. IN AREAS WHERE STRONGER
SURFACE HEATING CAN OCCUR...WHICH APPEARS MORE LIKELY INVOF THE
DRYLINE AND COMPOSITE FRONT /POSSIBLY-REINFORCED BY CONVECTIVE
OUTFLOW/ IN PARTS OF NWRN TX...MODERATE TO STRONG BUOYANCY SHOULD
DEVELOP. FARTHER E/NE...IF EARLY-DAY CONVECTION INDEED OCCURS INTO
THE WARM SECTOR...BUOYANCY WILL BE MORE MODEST. STILL...POCKETS OF
STRONGER BUOYANCY SHOULD OCCUR AS FAR NE AS IL...GIVEN A PLUME OF
UPPER 60S TO LOWER 70S SURFACE DEW POINTS CURRENTLY ACROSS THE LOWER
MS VALLEY.

LOW/DEEP-LAYER SHEAR WILL BE STRONG AND STRENGTHENING THROUGH THE
PERIOD AS THE VIGOROUS SHORTWAVE IMPULSE EJECTS ONTO THE PLAINS.
THIS WILL CONDITIONALLY YIELD QUITE FAVORABLE HODOGRAPHS FOR
ROTATING UPDRAFTS AND ORGANIZED LINE SEGMENTS CAPABLE OF PRODUCING
ALL SEVERE HAZARDS. THE GREATEST POTENTIAL RISK FOR SIGNIFICANT
SEVERE REMAINS POSSIBLE FROM NWRN TX TO THE OZARK PLATEAU.
HOWEVER...BY WED EVENING/NIGHT...THE FRONT IN THE SRN PLAINS WILL
SURGE BACK SWD...PROBABLY UNDERCUTTING UPDRAFTS AND YIELDING
INCREASINGLY ANAFRONTAL TSTM DEVELOPMENT WITH SWRN EXTENT.
CONTINUING RISKS FOR ALL SEVERE HAZARDS WILL LIKELY BE PROMINENT
WITH NERN EXTENT OVERNIGHT...ESPECIALLY AS CYCLOGENESIS PROBABLY
OCCURS TOWARDS THE MID-MS VALLEY.

..GRAMS/COHEN.. 04/16/2013

s00nr1
04-16-2013, 11:37 AM
Looks like they are leaning a little bit more toward a mix of the GFS and NAM in terms of frontal placement and thus the narrower corridor of MDT.

venture
04-16-2013, 11:37 AM
NWS Norman briefing for tomorrow...

xwEpNXmM3rE

jn1780
04-16-2013, 11:47 AM
Wow, thats a highly uncertain day 2 outlook. Looks like we will have to wait until tomorrow for more certainly.

kelroy55
04-16-2013, 12:11 PM
12Z GFS prog for 00Z Thurs (7pm Wed). Yikes.


http://68.226.77.253/skewts/GFS-test/036/SKT_GFS__KOUN.png


OK, am I the only one that has no idea what this is or how to read it?

venture
04-16-2013, 12:25 PM
OK, am I the only one that has no idea what this is or how to read it?

http://www.okctalk.com/current-events-open-topic/33635-oklahoma-severe-weather-discussion-april-2013-a-11.html#post636102

:)

Uncle Slayton
04-16-2013, 12:30 PM
http://www.okctalk.com/current-events-open-topic/33635-oklahoma-severe-weather-discussion-april-2013-a-11.html#post636102

:)

If I recall correctly, if the dashed line stays to the left of the solid line, those of us who "enjoy" extreme weather events might be in for a good day? Or vice versa?

venture
04-16-2013, 12:33 PM
If I recall correctly, if the dashed line stays to the left of the solid line, those of us who "enjoy" extreme weather events might be in for a good day? Or vice versa?

Dashed line left, solid line middle, dotted line right. Though it does get more complicated than that, but that is the general gist.

ou48A
04-16-2013, 12:33 PM
OK, am I the only one that has no idea what this is or how to read it?

I know just enough to know that it doesn’t look good.

I could be wrong but it looks like the wind profile from the surface on up would probably cause rotation, perhaps significant.
The strong jet stream winds should cause significant evacuation of air out the top which creates a syphon like effect that would enhance rising air and rotation. With want look like strong cape values a lot will depend on where the boundaries set up and how they interact.

Somebody please tell me where I'm wrong.

venture
04-16-2013, 12:36 PM
I know just enough to know that it doesn’t look good.

I could be wrong but it looks like the wind profile from the surface on up would probably cause rotation, perhaps significant.
The strong jet stream winds should cause significant evacuation of air out the top which creates a syphon like effect that would enhance rising air and rotation. With want look like strong cape values a lot will depend on where the boundaries set up and how they interact.

Somebody please tell me where I'm wrong.

That's a good summation right there. The link I posted in response to Kelroy is to a post I made yesterday that details the basic of reading the Skew-T and the various values.

venture
04-16-2013, 12:44 PM
NWS Norman is having a twitter Q&A right now

‏@darvinpin (https://twitter.com/darvinpin)36m (https://twitter.com/darvinpin/status/324220596139474944)
@NWSNorman (https://twitter.com/NWSNorman) where is the highest risk for tornados and what is the expected timeframe for that risk? Thanks!
NWS Norman ‏@NWSNorman (https://twitter.com/NWSNorman)26m (https://twitter.com/NWSNorman/status/324222979217190913)
@darvinpin (https://twitter.com/darvinpin) Based on our current forecast, the highest tornado potential would be SW OK and N TX, incl Altus, Hobart, Lawton, Wichita Falls

Mike Pilosof ‏@Mike_Pilosof (https://twitter.com/Mike_Pilosof)29m (https://twitter.com/Mike_Pilosof/status/324222681119617024)
@NWSNorman (https://twitter.com/NWSNorman) what's it looking like for Westherford/Clinton area tomorrow? #okwx (https://twitter.com/search?q=%23okwx&src=hash)
NWS Norman ‏@NWSNorman (https://twitter.com/NWSNorman)26m (https://twitter.com/NWSNorman/status/324223451898458113)
@Mike_Pilosof (https://twitter.com/Mike_Pilosof) Hey Mike, you guys will be on the line - again! Depends on the front. If you end up in the SE winds and warm temps, watch out!

ntxweathersooner ‏@ntxweathersoonr (https://twitter.com/ntxweathersoonr)29m (https://twitter.com/ntxweathersoonr/status/324222728930480129)
@NWSNorman (https://twitter.com/NWSNorman) Whats capping you expect and will there be morning convection
NWS Norman ‏@NWSNorman (https://twitter.com/NWSNorman)26m (https://twitter.com/NWSNorman/status/324223694731878401)
@ntxweathersoonr (https://twitter.com/ntxweathersoonr) Great question, and one of the big issues tomorrow. Weak cap would mean more storms and lower tornado potential.

ntxweathersooner ‏@ntxweathersoonr (https://twitter.com/ntxweathersoonr)30m (https://twitter.com/ntxweathersoonr/status/324222728930480129)
@NWSNorman (https://twitter.com/NWSNorman) Whats capping you expect and will there be morning convection
NWS Norman ‏@NWSNorman (https://twitter.com/NWSNorman)25m (https://twitter.com/NWSNorman/status/324224021010980865)
@ntxweathersoonr (https://twitter.com/ntxweathersoonr) We will probably have some morning storms, but they should be clear of the area in time for heating to occur. Still iffy!

Nick Rutledge ‏@NRutt2005 (https://twitter.com/NRutt2005)29m (https://twitter.com/NRutt2005/status/324222949357912064)
@NWSNorman (https://twitter.com/NWSNorman) What time do you think convection will take place tomorrow?
NWS Norman ‏@NWSNorman (https://twitter.com/NWSNorman)24m (https://twitter.com/NWSNorman/status/324224309654605824)
@NRutt2005 (https://twitter.com/NRutt2005) We may see morning storms, but we expect the stronger storms to start by 1-2pm

Mike McShan ‏@n5jky (https://twitter.com/n5jky)28m (https://twitter.com/n5jky/status/324223317227761664)
@NWSNorman (https://twitter.com/NWSNorman) Do you anticipate a typical year for severe wx in Oklahoma?
NWS Norman ‏@NWSNorman (https://twitter.com/NWSNorman)23m (https://twitter.com/NWSNorman/status/324224539687022592)
@n5jky (https://twitter.com/n5jky) Mike, I'm not sure what typical really means in OK. We haven't seen a lot of tornadoes yet this year, but that can change quickly!
Mike McShan ‏@n5jky (https://twitter.com/n5jky)21m (https://twitter.com/n5jky/status/324225788582981632)
@NWSNorman (https://twitter.com/NWSNorman) I understand; however I wondered if an algorithm can predict for a given year considering wx patterns, solar cycle, etc
NWS Norman ‏@NWSNorman (https://twitter.com/NWSNorman)14m (https://twitter.com/NWSNorman/status/324227471828467712)
@n5jky (https://twitter.com/n5jky) Not really. Even in a weather pattern that would seem quiet, it only takes one storm.



ntxweathersooner ‏@ntxweathersoonr (https://twitter.com/ntxweathersoonr)27m (https://twitter.com/ntxweathersoonr/status/324223672019714048)
@NWSNorman (https://twitter.com/NWSNorman) Also why the lack of more sig instability as indicated by SREF with such high dews? Clouds?
NWS Norman ‏@NWSNorman (https://twitter.com/NWSNorman)18m (https://twitter.com/NWSNorman/status/324225967990132736)
@ntxweathersoonr (https://twitter.com/ntxweathersoonr) Don't know for sure, but it may be due to clouds.

CrysCross ‏@ILoveCatsMore (https://twitter.com/ILoveCatsMore)27m (https://twitter.com/ILoveCatsMore/status/324223822213545984)
@NWSNorman (https://twitter.com/NWSNorman) random question, Do tornadoes have a temperature difference, if so is there a way to detect them with an inferred camera? #okwx (https://twitter.com/search?q=%23okwx&src=hash)
NWS Norman ‏@NWSNorman (https://twitter.com/NWSNorman)18m (https://twitter.com/NWSNorman/status/324226147992891392)
@ILoveCatsMore (https://twitter.com/ILoveCatsMore) interesting question! I'm not aware of any temperature difference that could be measured by infrared devices.

Jesse wagner ‏@jdubwx (https://twitter.com/jdubwx)27m (https://twitter.com/jdubwx/status/324224057933434880)
@NWSNorman (https://twitter.com/NWSNorman) do any of the models surge the front earlier than expected?
NWS Norman ‏@NWSNorman (https://twitter.com/NWSNorman)17m (https://twitter.com/NWSNorman/status/324226383180099584)
@jdubwx (https://twitter.com/jdubwx) Of the main models we're looking at, the GFS model moves the front furthest north, into S KS by tomorrow morning.

wade norris ‏@k5wpn Protected account (https://twitter.com/k5wpn)26m (https://twitter.com/k5wpn/status/324224348539981824)
@NWSNorman (https://twitter.com/NWSNorman) Guys what is the thinking on the warm front location tomorrow?
NWS Norman ‏@NWSNorman (https://twitter.com/NWSNorman)14m (https://twitter.com/NWSNorman/status/324227256857812994)
@k5wpn (https://twitter.com/k5wpn) That's the big question, Wade! We've got it north of I-40 by early afternoon.

Jenna Ostrow ‏@JFox0512 (https://twitter.com/JFox0512)13m (https://twitter.com/JFox0512/status/324227756583964672)
@NWSNorman (https://twitter.com/NWSNorman) according to our news in Wichita Falls, it's seems the possibility for more tornadic activity will be in OK. Would you agree?
NWS Norman ‏@NWSNorman (https://twitter.com/NWSNorman)8m (https://twitter.com/NWSNorman/status/324229201999822848)
@JFox0512 (https://twitter.com/JFox0512) Jenna, it will be close. It all depends on where the front ends up. There is a risk as far SW as Wichita Falls.

Stephen Gribble ‏@supergrib21 (https://twitter.com/supergrib21)13m (https://twitter.com/supergrib21/status/324227851433938944)
@NWSNorman (https://twitter.com/NWSNorman) im in altus and i know we are at the sw edge of the mod risk area tomorrow, but what are the chances of a PDS being issued for ok
NWS Norman ‏@NWSNorman (https://twitter.com/NWSNorman)8m (https://twitter.com/NWSNorman/status/324229458846445568)
@supergrib21 (https://twitter.com/supergrib21) Don't know. A PDS watch is just a tornado watch with some extra emphasis. I'd be surprised if we don't have a tornado watch.

david imy ‏@AgsAllTheWay (https://twitter.com/AgsAllTheWay)26m (https://twitter.com/AgsAllTheWay/status/324224738257940480)
@NWSNorman (https://twitter.com/NWSNorman) Looks like main forcing does not come out until tomorrow night. What will force storms during afternoon?
NWS Norman ‏@NWSNorman (https://twitter.com/NWSNorman)5m (https://twitter.com/NWSNorman/status/324230280141471744)
@AgsAllTheWay (https://twitter.com/AgsAllTheWay) Is this a trick question? ;-) Could be storms along the dry line/front if we can destabilize by early-mid afternoon.

Jesse wagner ‏@jdubwx (https://twitter.com/jdubwx)6m (https://twitter.com/jdubwx/status/324230182410006531)
@NWSNorman (https://twitter.com/NWSNorman) what is the nws definition of outbreak? That term is thrown around often now a days.
NWS Norman ‏@NWSNorman (https://twitter.com/NWSNorman)27s (https://twitter.com/NWSNorman/status/324231560154972160)
@jdubwx (https://twitter.com/jdubwx) We really don't have an official definition. See: http://www.spc.noaa.gov/publications/edwards/defpaper.pdf … (http://t.co/OXfrQKCdJD)

SoonerDave
04-16-2013, 01:06 PM
I'm sure this is purely subjective, but man, it seems like spring storm forecasting has become a lot more complex than it was when I was a kid.

By that I mean simply this: By the time April rolled around in Oklahoma, you just got accustomed to the notion that every three or four days, you should just darned well expect a big, hairy dryline to show up in advance of a front, with big, hairy storms in the west part of the state, hitting central OK later in the afternoon or early evening. And, to this day, I remember my gut twisting up into a knot as a kid every time I heard a "Tornado Warning" or one of the local weather beeps until I heard it was for an area away from where I lived. And I also learned to get nervous if things start approaching Chickasha, Tuttle, or Union City.

But these days, man, it seems like we're so much smarter about the weather in general that its made forecasting in the particular much dicier, because it at least seems we're much more aware of the variables than we were 30+ years ago.

And I'll also contend without an ounce of science to back it up that my perception is that OK weather has changed subtly since I was a kid. As I noted above, I was accustomed to the spring afternoon squall line, but those have seemed to be less prevalent in, oh, the last decade+ or so. And, as I said, I've not any data to back that up :) Just perception.

While I can't say my gut wrenches up anymore, its hard not to get a little on edge when you start hearing the NWS folks toss around the PDS possibilities in the (very) near future.

venture
04-16-2013, 01:08 PM
Chat wrapped up, here are the remaining posts...

NWS Norman ‏@NWSNorman (https://twitter.com/NWSNorman)18m (https://twitter.com/NWSNorman/status/324232769939066881)
@MarcusHylton (https://twitter.com/MarcusHylton) We could see storms start to go by 1-2pm in SW OK. C OK may not be impacted until after 5pm.

Ryan Tracy ‏@ryanEtracy (https://twitter.com/ryanEtracy)20m (https://twitter.com/ryanEtracy/status/324232480934744064)
@NWSNorman (https://twitter.com/NWSNorman) What exactly produces the crazy noise during an earthquake?
NWS Norman ‏@NWSNorman (https://twitter.com/NWSNorman)13m (https://twitter.com/NWSNorman/status/324234225119277057)
@ryanEtracy (https://twitter.com/ryanEtracy) We don't really do earthquakes, and I'm not really sure about the sound you're describing. http://earthquake.usgs.gov/learn/listen/index.php … (http://t.co/cIY1u2ETUs)

Todd Jones ‏@todjones (https://twitter.com/todjones)18m (https://twitter.com/todjones/status/324232910448242688)
@NWSNorman (https://twitter.com/NWSNorman) what is the best map to use to determine the best chance for tornadic activity? CAPE?
NWS Norman ‏@NWSNorman (https://twitter.com/NWSNorman)16m (https://twitter.com/NWSNorman/status/324233558174609408)
@todjones (https://twitter.com/todjones) This page from SPC has a lot of the forecast variables that meteorologists use to forecast severe weather - http://www.spc.noaa.gov/exper/mesoanalysis/ … (http://t.co/9r8UPClg3N)
Todd Jones ‏@todjones (https://twitter.com/todjones)14m (https://twitter.com/todjones/status/324234029455003648)
@NWSNorman (https://twitter.com/NWSNorman) Thank you. Is there a particular variable or two that I should be looking at?
NWS Norman ‏@NWSNorman (https://twitter.com/NWSNorman)12m (https://twitter.com/NWSNorman/status/324234374604288000)
@todjones (https://twitter.com/todjones) There are a lot of ingredients, and if they're not all there in the right mixture, tornadoes won't happen.

Paula Cain ‏@pkc114 (https://twitter.com/pkc114)17m (https://twitter.com/pkc114/status/324233472107483136)
@NWSNorman (https://twitter.com/NWSNorman) Get the feeling the confidence in tomorrow's forecast isn't particularly high. Can you rate the confidence level? #okwx (https://twitter.com/search?q=%23okwx&src=hash) #ponca (https://twitter.com/search?q=%23ponca&src=hash)
NWS Norman ‏@NWSNorman (https://twitter.com/NWSNorman)12m (https://twitter.com/NWSNorman/status/324234689428725760)
@pkc114 (https://twitter.com/pkc114) Confidence is not high, but it's getting higher. The front location and early morning storms ?? make it tougher than usual.

daisy rothschild ‏@daisyrothschild (https://twitter.com/daisyrothschild)17m (https://twitter.com/daisyrothschild/status/324233384303927296)
@NWSNorman (https://twitter.com/NWSNorman) thanks! Wondered if was a separate structure. Will severe weather in OK this week entail a complex tornado outbreak?
NWS Norman ‏@NWSNorman (https://twitter.com/NWSNorman)10m (https://twitter.com/NWSNorman/status/324235168548274176)
@daisyrothschild (https://twitter.com/daisyrothschild) Hard to say. We could have a lot of storms Wednesday and Wednesday night.

kelroy55
04-16-2013, 01:13 PM
http://www.okctalk.com/current-events-open-topic/33635-oklahoma-severe-weather-discussion-april-2013-a-11.html#post636102

:)


muchas gracias

jn1780
04-16-2013, 04:00 PM
So yeah, new models didn't clarify anything. NAM and GFS still don't agree. lol

venture
04-16-2013, 04:05 PM
Yeah I figured that would be the case as soon as NAM came in earlier. Sigh. NAM does have us completely socked in with clouds all day too, so that could be a telling tail if we see any clearing at all tomorrow.

venture
04-16-2013, 04:25 PM
OUN's Afternoon Discussion sums up things very well...

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORMAN OK
333 PM CDT TUE APR 16 2013


.DISCUSSION...
WITHIN COOL NORTHEASTERLY FLOW TO THE NORTH OF A SLOWLY
RETREATING WARM FRONT...MUCH OF OKLAHOMA HAS REMAINED CLOUDY AND
UNSEASONABLY COOL TODAY. A FEW SPOTS ACROSS EXTREME SOUTHERN
OKLAHOMA AND WESTERN NORTH TEXAS HAVE EXPERIENCED SOME HEATING
TODAY. THIS FRONTAL FEATURE WILL CONTINUE TO SLOWLY LIFT NORTHWARD
THROUGH THE EVENING AND OVERNIGHT. WHILE CAPPING REMAINS AN
ISSUE...IT IS POSSIBLE THAT AN ISOLATED STORM OR TWO MAY DEVELOP
IN VICINITY OF THE FRONT OVER CENTRAL TEXAS...SOME OF THIS
ACTIVITY MAY EVENTUALLY SPREAD NORTHWARD INTO NORTH TEXAS BY
AROUND 00-03Z. WHILE SOME LOW END SEVERE POTENTIAL WILL EXIST WITH
THIS ACTIVITY...SIGNIFICANT SEVERE WEATHER WILL REMAIN UNLIKELY
TODAY AND TONIGHT. OVERNIGHT...AS LOW LEVEL WARM ADVECTION RAMPS
UP WITH AN ACTIVE LLJ...EXPECT AT LEAST SCATTERED SHOWER AND
THUNDERSTORM ACTIVITY OVER FAR NORTHERN OKLAHOMA. WITH MODEST
ELEVATED INSTABILITY...A SEVERE HAIL THREAT WILL EXIST WITH THE
STRONGEST ELEVATED STORMS OVERNIGHT.


UNCERTAINTY REMAINS RELATIVELY HIGH REGARDING SEVERE POTENTIAL
TOMORROW. MUCH OF THIS WILL BE TIED TO MESOSCALE FEATURES THAT
WILL LIKELY NOT BE RESOLVED UNTIL TOMORROW MORNING...AS MODELS
CONTINUE TO DEVIATE FROM ONE ANOTHER OVER THE NEXT 24 TO 48 HR.
CURRENT THINKING IS CLOSEST TO LATEST ECMWF...WHICH ESTABLISHES A
SW TO NE ORIENTED FARM FRONT FROM NORTHEAST OKLAHOMA INTO
SOUTHEAST KANSAS AND NORTHWEST MISSOURI. THIS WOULD PLACE THE
MAJORITY OF THE FA IN A MODERATELY UNSTABLE WARM SECTOR...WITH
IMPRESSIVE LOW LEVEL SHEAR AND VERY FAVORABLE WIND PROFILES FOR
SUPERCELL DEVELOPMENT. ATTM...THE ONLY REMAINING QUESTION IS HOW
MUCH MORNING CONVECTION WILL BE PRESENT...WHICH MAY LIMIT
INSTABILITY. STILL...EVEN WITH ONLY 1500 TO 2000 J/KG OF
CAPE...MAGNITUDE OF LOW LEVEL SHEAR AND RELATIVELY LOW LCLS WOULD
SUPPORT TORNADOES...IF STORMS CAN PERSIST AND REMAIN RELATIVELY
DISCRETE. THE FRONT MAY ALSO SERVE AS AN ENHANCEMENT TO LOW LEVEL
SRH...THOUGH MID LEVEL WINDS NEARLY PARALLEL TO SAID BOUNDARY MAY
LEAD TO A RATHER MESSY SCENARIO IN VICINITY OF THE FRONT. WITH
RATHER WEAK CAPPING ACROSS MUCH OF THE WARM SECTOR DURING THE
DAY...SEVERE STORMS WILL BE POSSIBLE AS EARLY AS 1 PM...WITH
ADDITIONAL DEVELOPMENT POSSIBLE NEAR THE DRYLINE ACROSS SOUTHWEST
OKLAHOMA AND WESTERN NORTH TEXAS. IF APPRECIABLE INSTABILITY CAN
BE REALIZED...AND STORMS CAN REMAIN SOMEWHAT DISCRETE IN THE OPEN
WARM SECTOR...A POTENTIAL WIDESPREAD SEVERE WEATHER EVENT MAY
UNFOLD THROUGHOUT THE EARLY AFTERNOON AND EVENING HOURS. THIS
WOULD INCLUDE POTENTIAL FOR VERY LARGE HAIL TO THE SIZE OF
BASEBALLS...DAMAGING WINDS IN EXCESS OF 70 MPH...AND SEVERAL
TORNADOES. AS STATED ABOVE...THE EVENT WILL BE STRONGLY TIED TO
THE ADVANCEMENT OF THE WARM FRONT AND ANY EARLY DAY ELEVATED
CONVECTION...WHICH REMAINS DIFFICULT TO PINPOINT ATTM.


A STRONG COLD FRONT WILL SURGE SOUTHWARD OVERNIGHT WEDNESDAY
NIGHT INTO THURSDAY MORNING. TORNADO POTENTIAL WILL DIMINISH
RAPIDLY AS THIS OCCURS...BUT A THREAT OF LARGE HAIL WILL REMAIN
THROUGH AT LEAST 4 AM THURSDAY. THERE MAY EVEN BEE A BRIEF WINDOW
OF OPPORTUNITY FOR A RAIN SNOW MIX OR RAIN/SNOW/SLEET MIX OVER
PORTIONS OF NORTHWEST OKLAHOMA AS COLD AIR FILLS IN. HOWEVER...NO
ACCUMULATIONS ARE EXPECTED NOR ARE ANY SIGNIFICANT IMPACTS.


THE OVERALL WEATHER PATTERN WILL SETTLE DOWN QUICKLY BY
THURSDAY...THOUGH A DECENT FREEZE CAN BE EXPECTED FRIDAY MORNING
NORTH AND WEST OF I-44. A GRADUAL WARMUP IS THEN FORECAST...WITH A
SECOND FRONT MAKING ITS WAY THROUGH THE AREA BY EARLY NEXT WEEK.

Uncle Slayton
04-16-2013, 05:19 PM
Looks like they're gonna have to hire an entire staff of gardeners to trim the hedges around those bets...

SoonerDave
04-16-2013, 05:24 PM
I personally think even the TV folks deserve quite a bit of kudos for not hyping this very much. I think they've (at least the ones I've seen), have been very measured in pointing out the possibility for a bad severe weather day, but also acknowledging that not all the dominoes may line up quite right.

jn1780
04-16-2013, 05:26 PM
I personally think even the TV folks deserve quite a bit of kudos for not hyping this very much. I think they've (at least the ones I've seen), have been very measured in pointing out the possibility for a bad severe weather day, but also acknowledging that not all the dominoes may line up quite right.

Ha! Not Morgan! He's pretty much saying there's going to be a tornado outbreak tomorrow.

jn1780
04-16-2013, 05:29 PM
Looks like they're gonna have to hire an entire staff of gardeners to trim the hedges around those bets...

There's a 100% chance someone is going to say the NWS doesn't know what their doing this time tomorrow. Poor guys can't win.

venture
04-16-2013, 05:37 PM
There's a 100% chance someone is going to say the NWS doesn't know what their doing this time tomorrow. Poor guys can't win.

Mmmhmm. No one here though...at least there better not be. As descriptive as it gets here, there shouldn't be any surprises tomorrow. :-P

Uncle Slayton
04-16-2013, 07:05 PM
There's a 100% chance someone is going to say the NWS doesn't know what their doing this time tomorrow. Poor guys can't win.

I'll be pleasantly surprised if the sky starts twisting tomorrow, but the gut feeling I have is that this one's gonna have more bust in it than an MTV Spring Break kegger. I will be happy to be proven wrong.

bchris02
04-16-2013, 07:09 PM
It looks like more freezing temperatures next week. This year I don't suggest anybody do any planting until the middle of May.

Its hard to believe next week is the last week of April and we will still be wearing sweaters and heavy winter coats.

Uncle Slayton
04-16-2013, 07:13 PM
It looks like more freezing temperatures next week. This year I don't suggest anybody do any planting until the middle of May.

I was disgusted with myself for not getting anything in the ground, but now that's looking positively prescient. My asparagus has had more beatdowns than Chris Brown's girlfriend.

SomeGuy
04-16-2013, 07:16 PM
Getting ready to clear out the shelter for possible tornadoes. Might as well stock up on batteries too

SoonerDave
04-16-2013, 07:28 PM
Ha! Not Morgan! He's pretty much saying there's going to be a tornado outbreak tomorrow.

I figured Morgan as the exception was a given.....

bchris02
04-16-2013, 07:32 PM
[QUOTE=jn1780;636658]Ha! Not Morgan! He's pretty much saying there's going to be a tornado outbreak tomorrow.[/QUOE]

I figured Morgan as the exception was a given.....

Is Mike Morgan a good weatherman to watch for an accurate prediction, or is he all about sensationalism? David Payne doesn't seem to be pumping up the tornado threat quite as much as Morgan.

SOONER8693
04-16-2013, 07:59 PM
[QUOTE=SoonerDave;636703]

Is Mike Morgan a good weatherman to watch for an accurate prediction, or is he all about sensationalism? David Payne doesn't seem to be pumping up the tornado threat quite as much as Morgan.
There's a reason he's called Mike Morgasm in weather circles.

td25er
04-16-2013, 08:57 PM
Yeah, this has me bummed. I hope it doesn't take the wind out of the sails of tomorrow's outbreak. Although, I have a sneaking suspicion, to modify Venture's analogy slightly, we may be in for just some crappy tasting water tomorrow rather than a good pot of stew, or even (were I to dare hope), a hot pot of chili.

Yeah, I was hoping for widespread destruction and maybe a death or two.

venture
04-16-2013, 09:04 PM
00Z NAM is the same as it has been. Waiting for GFS to see if that changes any.

bchris02
04-16-2013, 09:09 PM
Mike Morgan is pumping up a major tornado outbreak with 80MPH winds and baseball or larger sized hail. If he's right, this could end up being a major event with a lot of destruction in OKC.

LocoAko
04-16-2013, 09:22 PM
00Z NAM is pretty scary from early evening into the night. The helicity along the I-44 from LAW into the metro is ridiculously high (nearly 500 m2/s2 for 0-3km SRH and nearly 300 m2/s2 for 0-1m SRH in Chickasha at 3Z). Still has the front further SE than most other models and morning crapvection is still a risk but definitely the potential for some really serious weather tomorrow evening...

venture
04-16-2013, 09:26 PM
Loco...

I've been having this thought of if the front stalls out near the Metro...what is to keep it from being a tornado machine we've seen warm fronts be in the past. Normally these are Kansas type setups, but I remember back to a couple years ago in North central OK where an old boundary just sat there and kept dropping left and right. Usually we look for storms getting rooted in boundaries for that additional shear to assist them. It very well could be what we get tomorrow.

Nothing says it has to be 80 degrees and sunny tomorrow. How many tornado days do we see in more cool setups but the shear/helicity overcomes it.

Just thinking aloud randomly...not saying that this is what will happen.

bchris02
04-16-2013, 09:31 PM
What does this look like as far as F4/F5 potential?

LocoAko
04-16-2013, 09:33 PM
00Z tomorrow night for Frederick, OK off the 00Z NAM. Amazingly textbook sickle-shaped hodograph.

http://i46.tinypic.com/25880zo.png

LocoAko
04-16-2013, 09:35 PM
Loco...

I've been having this thought of if the front stalls out near the Metro...what is to keep it from being a tornado machine we've seen warm fronts be in the past. Normally these are Kansas type setups, but I remember back to a couple years ago in North central OK where an old boundary just sat there and kept dropping left and right. Usually we look for storms getting rooted in boundaries for that additional shear to assist them. It very well could be what we get tomorrow.

Nothing says it has to be 80 degrees and sunny tomorrow. How many tornado days do we see in more cool setups but the shear/helicity overcomes it.

Just thinking aloud randomly...not saying that this is what will happen.

Definitely. You know I'm new to the area but I think on paper this has the potential to be a pretty hairy situation for the metro tomorrow evening, esp if the front sets up exactly on or just NW of 44. We shall see. I'll be out chasing tomorrow, but night chasing and chasing in the metro is just stressful.

jn1780
04-16-2013, 09:35 PM
What does this look like as far as F4/F5 potential?

The potential for everything is there. Including nothing happening at all. lol

SoonerBoy18
04-16-2013, 09:39 PM
The potential for everything is there. Including nothing happening at all. lol

I'm gonna try my hardest not to get to excited over the fact of possible Tornadoes, after how last week turned out =(

venture
04-16-2013, 09:39 PM
Definitely. You know I'm new to the area but I think on paper this has the potential to be a pretty hairy situation for the metro tomorrow evening, esp if the front sets up exactly on or just NW of 44. We shall see. I'll be out chasing tomorrow, but night chasing and chasing in the metro is just stressful.

Be careful out there. I did a few night chases in my 13 years doing it...hated them. LOL Of course I hate the chaser convergence as well now, so I just sit back and watch from home. Which hasn't been too bad though. Still managed to see a tornado or two from the front yard. LOL

venture
04-16-2013, 09:40 PM
00Z GFS rolling in now. Drum roll....

venture
04-16-2013, 10:01 PM
GFS stubborn as well.

LocoAko
04-16-2013, 10:07 PM
Crazy discrepencies so close to the event. Oy vey. Dryline still definitely looks nasty on OK/TX western border on the GFS though. Tricky tricky.

boscorama
04-16-2013, 10:11 PM
Getting ready to clear out the shelter for possible tornadoes. Might as well stock up on batteries too
I do this twice a year. Recently I draped aluminum foil over chairs, water bottles, candles, etc,, to keep the dust under control. Having marveled at that brainstorm, perhaps I'll humor my inner prepper with some canned goods (and can opener, of course).

damonsmuz
04-16-2013, 10:49 PM
Looks like the 00Z GFS did not initialize too well with the warm front location.

I haven't been a big fan of the GFS for the past few days,but this much discrepancy b/w the NAM and GFS less than 18 hours from the event unfolding is crazy.

Now on to the EURO, time to make a pot of coffee... or take an energy shot.

bchris02
04-16-2013, 10:54 PM
Looks like the 00Z GFS did not initialize too well with the warm front location.

I haven't been a big fan of the GFS for the past few days,but this much discrepancy b/w the NAM and GFS less than 18 hours from the event unfolding is crazy.

Now on to the EURO, time to make a pot of coffee... or take an energy shot.

I am not a meteorologist so I have a difficult time reading the charts posted on this thread, but from the models you've seen, would you say my apartment will likely still be standing at this time tomorrow night or not?

venture
04-16-2013, 10:58 PM
I am not a meteorologist so I have a difficult time reading the charts posted on this thread, but from the models you've seen, would you say my apartment will likely still be standing at this time tomorrow night or not?

Depends if the earth finally opens up under us and unveils the new Oklahoma Volcano that's been brewing. ;)

Plutonic Panda
04-16-2013, 11:12 PM
Depends if the earth finally opens up under us and unveils the new Oklahoma Volcano that's been brewing. ;)Maybe Yellowstone is determined to become the biggest volcano in the solar system? lol

Anonymous.
04-16-2013, 11:23 PM
Echos popping up in extreme NW OK into the panhandle as of ~12:20.

This could be the beginning of morning convection that casts disgusting clouds over the NW 2/3 of the state.

Warm front is still floating around SE OK. Looks like it may be jogging back NW. The moisture needed to fuel these things is behind it. Unless it is here by mid-morning in C OK. It may be time to sound the bust sirens.

venture
04-16-2013, 11:26 PM
Cell near Coldwater, KS is already severe.

damonsmuz
04-16-2013, 11:33 PM
Something I have been trying to look at is let's say the warm front does make it to OKC and slightly north. At what time does the warm front need to make it to the Metro by in order for OKC to see a more significant severe threat. Just because we get the warmer air in here doesn't mean squat if that warm air isn't in place by a certain time. But what is that time? Peak heating? Or does it need to be in here before or after? Or does it even matter?

And if we get enough storm activity in Kansas, how does the cold pool of air over Kansas impact warm front movement? Does it? Does it not? I don't expect anyone here to know the answer to this. But, these are just 2 of the gazillion questions running through my head...

venture
04-16-2013, 11:45 PM
http://www.spc.noaa.gov/products/md/mcd0488.gif
MESOSCALE DISCUSSION 0488
NWS STORM PREDICTION CENTER NORMAN OK
1241 AM CDT WED APR 17 2013

AREAS AFFECTED...NW OK...SCNTRL KS

CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE

VALID 170541Z - 170715Z

PROBABILITY OF WATCH ISSUANCE...40 PERCENT

SUMMARY...AN ISOLATED THREAT FOR LARGE HAIL WILL LIKELY DEVELOP
ACROSS PARTS OF NW OK AND SCNTRL KS OVER THE NEXT FEW HOURS. WW
ISSUANCE IS BEING CONSIDERED.

DISCUSSION...THE LATEST MESOANALYSIS SHOWS A 4O TO 50 KT LOW-LEVEL
JET EXTENDING NEWD ACROSS NW TX...WRN OK INTO SCNTRL KS WHERE STRONG
WARM ADVECTION IS OCCURRING. ALTHOUGH THE BOUNDARY LAYER IS STABLE
ACROSS THE MCD AREA...STRONG INSTABILITY IS LOCATED ACROSS THE ERN
TX PANHANDLE AND WRN OK WHERE MUCAPE VALUES ARE ESTIMATED IN THE
2500 TO 3500 J/KG RANGE. AS WARM ADVECTION CONTINUES LATE
TONIGHT...INSTABILITY SHOULD INCREASE NWD ACROSS SCNTRL KS WITH
CONVECTION EXPANDING IN COVERAGE AS THE LOW-LEVEL JET STRENGTHENS.
THIS ELEVATED INSTABILITY...STRONG EFFECTIVE SHEAR AND STEEP
MID-LEVEL LAPSE RATES WILL BE FAVORABLE FOR LARGE HAIL. ANY SEVERE
THREAT IS EXPECTED TO REMAIN ISOLATED.

..BROYLES/HART.. 04/17/2013

venture
04-16-2013, 11:53 PM
Something I have been trying to look at is let's say the warm front does make it to OKC and slightly north. At what time does the warm front need to make it to the Metro by in order for OKC to see a more significant severe threat. Just because we get the warmer air in here doesn't mean squat if that warm air isn't in place by a certain time. But what is that time? Peak heating? Or does it need to be in here before or after? Or does it even matter?

And if we get enough storm activity in Kansas, how does the cold pool of air over Kansas impact warm front movement? Does it? Does it not? I don't expect anyone here to know the answer to this. But, these are just 2 of the gazillion questions running through my head...

Yeah I'm still trying to get my mind around how things are going to go. Something has to be said though, this has yet to be an easy year with a classic boring setup. LOL

HRRR has the warm front through OKC around 10AM, NAM is pretty close to that. So we'll see how far it makes it. I'm almost inclined to do an average between NAM and GFS. GFS is way out there, but maybe NAM is just being too conservative in how far it wants to move it. We've seen several big events take place in colder environments than what we normally want. We also see perfect setups just grunge out with crapvection and provide a day of watching a bunch of heavy rain and small hail storms.

Are we also perhaps underplaying the severe squall line that will come through tomorrow night? With the amount of shear out there, we very well could see many wind damage reports and embedded circulations. Then depending on the line, we could have a broken line where inflow could get established in some cells and give us some trouble or we could have the classic tail end charlie cells that spin away.

Just a few minutes away now from the new Day 1. It'll be interesting to see what SPC is thinking now to. I don't think they would go to High with it still being very conditional, but I think could go with some very strong //conditional// wording and probabilities.

venture
04-17-2013, 12:05 AM
Moderate Risk Remains...

DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0100 AM CDT WED APR 17 2013


VALID 171200Z - 181200Z


...THERE IS A MDT RISK OF SVR TSTMS ACROSS PARTS OF NORTH TX AND OK TO EASTERN KS/SOUTHWEST MO...


...THERE IS A SLGT RISK OF SVR TSTMS FROM THE SOUTHERN PLAINS TO THE LOWER MO VALLEY/MIDWEST...


...SYNOPSIS...
A PROMINENT/NEUTRAL TO SLIGHT POSITIVE-TILT UPPER TROUGH OVER THE WESTERN CONUS WILL CONTINUE EASTWARD TODAY FROM THE GREAT BASIN/ ROCKIES TO THE HIGH PLAINS...WITH PHASED POLAR/SUBTROPICAL JETS INCREASINGLY INFLUENCING THE CENTRAL/SOUTHERN PLAINS INTO THIS AFTERNOON/TONIGHT. SURFACE CYCLOGENESIS IS EXPECTED ACROSS THE SOUTHERN HIGH PLAINS...WITH AN EASTWARD MIXING DRYLINE ACROSS NORTHWEST/WEST-CENTRAL TX. NORTHEASTWARD FROM THE SURFACE LOW...A SURFACE FRONTAL ZONE WILL ONLY MOVE SLOWLY ACROSS OK/NORTHWEST TX THROUGH THE AFTERNOON...WITH A MUCH MORE AGGRESSIVE NORTHWARD PUSH AS A WARM FRONT ACROSS THE LOWER MO VALLEY/MIDWEST THROUGH TONIGHT IN RESPONSE TO LATE PERIOD SURFACE CYCLOGENESIS.


...SOUTHERN PLAINS TO LOWER MO VALLEY/MIDWEST...
WELL-ABOVE TYPICAL GUIDANCE SPREAD CONTINUES INTO THE DAY 1 PERIOD...ACCENTUATED BY A MUCH MORE NORTHWARD AND SEEMINGLY LESS LIKELY SOLUTION OF THE 00Z GFS AS COMPARED TO THE 00Z NAM/12Z ECMWF.
AMONG OTHER UNCERTAINTIES...THIS IS A FACTOR FOR ONLY MODEST CONFIDENCE IN SPECIFIC DETAILS LATER TODAY. EVEN SO...POTENTIALLY WIDESPREAD/MULTI-FACETED SEVERE WEATHER IS LIKELY ESPECIALLY INTO THIS AFTERNOON/EVENING.


INITIALLY...ELEVATED STRONG/POTENTIALLY SEVERE TSTMS CAPABLE OF HAIL WILL LIKELY BE ONGOING THIS MORNING ACROSS PORTIONS OF THE LOWER/MIDDLE MO VALLEY AND ADJACENT MIDWEST. THIS WILL BE IN ASSOCIATION WITH A STRONG LOW LEVEL JET/WARM ADVECTION REGIME.


FARTHER SOUTH...A MORE WIDESPREAD/SURFACE BASED TSTM THREAT WILL LIKELY EVOLVE AS EARLY AS THIS AFTERNOON...BUT ESPECIALLY INTO THIS EVENING/TONIGHT ACROSS THE SOUTHERN PLAINS TO THE LOWER MO VALLEY IN GENERAL VICINITY OF AFOREMENTIONED FRONTAL ZONE. WHILE NOT NECESSARILY LIKELY...THERE MAY BE SOME POSSIBILITY THAT TSTMS DEVELOP RELATIVELY EARLY IN THE AFTERNOON ACROSS PORTIONS OF NORTH TX INTO EASTERN OK AND PERHAPS EVEN THE OZARKS...AND POTENTIALLY BECOME SURFACE BASED WITHIN AN INCREASINGLY MOIST/UNINHIBITED BOUNDARY LAYER. SHOULD THIS OCCUR...DISCRETE SUPERCELLS CAPABLE OF LARGE HAIL/TORNADOES WOULD BE POSSIBLE.


SURFACE BASED DEVELOPMENT DOES SEEM MORE PROBABLE NEAR THE TRIPLE POINT VICINITY OF DRYLINE/COMPOSITE FRONT...UNDER THE INFLUENCE OF A BIT STRONGER HEATING/MASS CONVERGENCE. THIS WOULD BE ACROSS PARTS OF NORTH-CENTRAL/NORTHWEST TX INTO SOUTHWEST/SOUTH-CENTRAL OK.
ESPECIALLY GIVEN AN INTENSIFYING LOW LEVEL JET TOWARD/AFTER DARK...POTENTIAL WOULD EXIST FOR LARGE HAIL AND PERHAPS A FEW STRONG TORNADOES ACROSS THIS REGION.


OTHERWISE...STORMS ARE EXPECTED TO INCREASE AFTER DARK IN VICINITY OF THE SOUTH-SOUTHWEST TO NORTH-NORTHEAST ORIENTED FRONTAL ZONE ACROSS OK INTO THE LOWER MO VALLEY AND EVENTUALLY MIDDLE MS VALLEY MIDWEST. SOME POTENTIAL FOR SURFACE BASED TSTMS/SUPERCELLS AND ASSOCIATED DAMAGING WIND/TORNADO POTENTIAL WILL EXIST MAINLY THROUGH THE EVENING IMMEDIATELY NEAR THE FRONT...BUT THERE WILL LIKELY BE A TENDENCY FOR UPDRAFTS TO BE UNDERCUT BY THE NOCTURNALLY SOUTH/SOUTHEASTWARD-ACCELERATING COLD FRONT. AS SUCH...LARGE HAIL MAY BECOME THE MOST PROBABLE/MORE WIDESPREAD CONCERN ACROSS THE REGION.


...TN VALLEY TO CENTRAL/SOUTHERN APPALACHIANS...
AT LEAST ISOLATED TO WIDELY SCATTERED TSTMS ARE EXPECTED TO DIURNALLY INCREASE THIS AFTERNOON ACROSS THE REGION. WHILE FORCING ON THE LARGE SCALE WILL BE MODEST AND MID-LEVEL LAPSE RATES/VERTICAL SHEAR WILL BE WEAK...STEEPENING LOW LEVEL LAPSE RATES DURING THE AFTERNOON MAY CONTRIBUTE TO SOME POTENTIAL FOR EPISODIC BOUTS OF LOCALLY DAMAGING WINDS/HAIL.

venture
04-17-2013, 12:07 AM
The outline...MDT risk is bigger again.

http://www.spc.noaa.gov/products/outlook/day1otlk_1200.gif

http://www.spc.noaa.gov/products/outlook/day1probotlk_1200_torn.gif

http://www.spc.noaa.gov/products/outlook/day1probotlk_1200_wind.gif

http://www.spc.noaa.gov/products/outlook/day1probotlk_1200_hail.gif

jn1780
04-17-2013, 12:17 AM
So their going on the belief that GFS isn't completely crazy and the front will end up somewhere in northern oklahoma.

venture
04-17-2013, 12:17 AM
So their discussion really doesn't answer anything. They are pretty much in the same position we are, except they are a bit more certain. The good thing out of all of this. The big show is in a very chaser friendly area. I loved chasing that area. It also gives us plenty of lead time for when things move into the Metro area.