11/27/05 FCST: Southern Plains

[afischer]

Anyone perusing the latest NAM guidance will note things look a might bit breezier and even more wrapped up. I have no problems with this if it pans out... but accordingly, forecast uvm fields are far stronger than before and suggest that forcing for ascent with this system will *not* exactly be subtle... lol. Of course, the devil will be in the details... boundary layer destabilization, convective mode, forward speed of the occluded front etc. I have to work until 2pm but am still thinking I'd prefer to play the northeast quadrant of the developing closed low anyway, where synoptic lift might be comparatively weaker and where the dryline/cold front/occluded front thing isn't mixing eastward at 9999mph. I'll be watching things closely in the morning. If nothing else it sure is an exciting system close to home!

 

[Bill Schintler]

Chase target for November 27

Chase target:
Miami, OK (along I-44 in the extreme NERN corner of the state)

Timing:
Storm initiation around noon.

Storm type and evolution:
All types of severe WX will be possible, including a small tornado threat. Storm motion will be very rapid, with cells traveling to the NE at 60 mph.

Discussion:
An active fall storm system will affect much of the central US with a full spectrum of hazardous WX including severe storms and heavy snow over the next 48 hours. Active WX setup upstairs at 00Z, with 180kt H3 max over NRN CA diving SE towards base of negatively-tilted trough. Several embedded waves were noted, with lead S/WV lifting through ERN NM/WRN TX along with primary wave in exit region of streak now moving through AZ. At the SFC, slow cyclogenesis has commenced in WRN KS. This low begin to rapidly deepen beginning this time tomorrow when the best upper support arrives, and it will take a track through NWRN IA into MN through the day Monday as heavy snow develops to the N and W of this track.

Tonight:
SFC WF extends E from the low along the NE/KS border and IA/MO border. A 60kt LLJ is developing and nosing into WRN IA. Significant moisture and instability, rooted just above the BL, is being advected towards the upper-Midwest. 00Z TOP and OAX soundings both show 100-150mb deep moist layer along with region of steep lapse rates just above a stable layer. Later this evening, H85 WF should bisect IA from NW to SE. Convergence along front, and isentropic lift of around –5ub/S on 290K through 296K surfaces to the N of the front may provide the focus for some elevated showers and storms in NRN IA and SRN MN. No severe WX is expected.

Sunday:
The SFC low will rapidly deepen and lift from NWRN OK into KS. A secondary developing WF along the OK and KS border will provide the focus for severe WX early in the afternoon, while a dryline dives to the E towards the target by mid-afternoon. The resulting triple point will lift rapidly off to the NE with the advance of the DL. As is often the case this late in the season, moderate instability will be coupled with very strong mid- and upper-level forcing and shear. Mid-afternoon MLCAPE’s will generally be below 1000J/kG while deep layer shear to 70 kts in left-exit region of H5 streak will result in very long but only slightly curved hodographs which will support organized severe WX with the primary threat severe wind gusts to 80 mph.

Sunday night and Monday:
Attention will turn from severe convective WX to the first significant snowstorm of the season. Main axis of heavy snow will occur along an axis of deformation to the N and W of the SFC low track in SD/ND/MN.

- bill

 

[Ronnie Bradley]

SPC's latest day 2 outlook states that there may be embedded supercells within the squall line as it marches east tomorrow PM. Right now, they have just a slight risk out but I think a moderate risk, provided that all this gels together at the right time, is in order. They also stated that there will be enough directional shear for some discreet cells out ahead of the squall line, particularily over the Ozarks and back toward extreme NE OK.
By the time it reaches my area, it will be dark (egads!!) so it ought to be interesting for me tomorrow!
Right now, KLZK VWP is showing 15-20 kt SSE surface winds, 40 kt S winds around 3,000 ft and S / SSW winds in varying wind speeds above 5,000 ft, veering toward the right with height. Upper level winds are at 90 kts @ 35kft out of the SSW. Numerous showers are lifting north @ 40 to 45mph.

 

[nickgrillo]

--> http://www.midwestchase.com/november_sat_outlook14.gif

That surface analysis is for 21z and the outlined threat area is for through all of tomorrow. The approaching mid-level impulse coupling with low-level convergance ahead of the dryline should provide sufficient upward motion to release instability... Highly favorable deep and low-level shear will enhance storm organization and supercell formation is quite likely. With the main threats being both damaging winds and isolated tornadoes.. Unmodified DMO NAM model sounding for 21z SUN shows a well-mixed boundary layer -- owed to strong flow present with nearly dry adiabatic lapse rates. Strong rotation (from +100kt SW flow at 250mb, to backed southeast flow at the sfc) yields widespread >60kt deep-layer shear across the warm sector -- indicating the potential for long-lived updrafts. In addition, >55F sfc Tds yields marginal to moderate sfc-based instability across the warm sector, which when combined with 250-400m2/s2 0-1km SRH indicates the potential for an isolated strong tornado or two. Storms may initially form ahead of the dryline around 21z across western MO... Storms should then evolve into a broken line by evening, with a continued threat for damaging winds and isolated tornadoes well into IL. As of now, I think a target of Sedalia, MO would be a pretty good starting point... Good luck to all tomorrow!

 

[Jonathan Whitehead]

bullseye MDT risk for Ozarks and pts east to Eastern sections of Norther Ark and Southern MO. w/ attendent 5% region
http://www.spc.noaa.gov/products/outlook/day1otlk.html

Believe this will be where triple point will occur and move east to NE from there

 

[Dan Chaffee]

I noticed both ETA and GFS are showing a well defined dry incursion at
700mb at 0Z Mon; just ahead of the progged dryline bulge in SE
Ks at that time. Very classic synoptic set up in many ways. I like that the strongest veering with height is in the lowest 1-2 Km. However, I expect
no storm slower than 40kts and a good deal faster S of MO., with
storm motions almost due N. That actually can help with the road situation. Considering the likely speeds and locations for most of the prospecticve supercell activity, these storms may be unchaseable. Well, at least the jungles have no leaves now A small window of opportunity may be there for extreme E. Ks and W Mo by late afternoon. Point, click and get out of the way, may be the best one can do for this round--good luck to anyone who gives it a shot.

 

[Mark Farnik]

Wow. This November has been absolutely relentless in terms of tornado outbreaks and general severe weather, and tha trend looks to continue today.
From the SPC Day 1 1300 UTC Outlook:
MORE SIGNIFICANT SEVERE THUNDERSTORM DEVELOPMENT SHOULD OCCUR NEAR
21Z JUST AHEAD OF THE SURFACE COLD FRONT FROM ERN KS/WRN MO INTO ERN
OK/WRN AR AND THE ARKLATEX REGION. ENVIRONMENT WILL BECOME QUITE
FAVORABLE FOR TORNADIC SUPERCELLS WITH EXTREME LOW/DEEP LAYER SHEAR
AND HIGH VALUES OF BOUNDARY LAYER RH. LARGE HODOGRAPHS /0-1 KM SRH
IN EXCESS OF 250 M2/S2 / SUGGEST SUSTAINED SUPERCELLS WILL BE
CAPABLE OF TORNADOES...A FEW OF WHICH COULD BE SIGNIFICANT.

The setup is highly conducive for a few potentially strong, damaging tornadoes, especially across far east KS/southwestern MO/northern AR/far northeastern OK with initial discrete supercells that form on the triple point, which should develop here around mid-afternoon. :shock: The shear this system has to work with is insane for this time of year and will overcome the issue of SBCAPE's of less than 1000 with no problem. I think I'm going to call my aunt; she lives southwest of Jefferson City. I love her dearly, but she pays no attention to the weather. And this is going to be a day, I fear, where paying attention could save lives. Anyone living in an area from Jefferson City, MO, to Poplar Bluff, MO to Little Rock, AR to Tulsa, OK to Overland Park, KS needs to be on high alert this afternoon and evening. Good luck to anyone who tries to chase these storms; they'll be haulin' ass northeast through the Ozark Jungle!

 

[afischer]

Pretty impressive... the base of the mid/upper trof is starting to translate through west TX, and the Jayton profiler has shown mid-level (6-8km) flow of 110-120kts during the past 3 hrs. This is 15-25kts stronger (!!!) than what the 12z NAM has for a 500mb wind max from 12-15Z. I don't know that this specifically will have much of an impact on the convective evolution later today, but I wouldn't be surprised to see an even deeper surface low develop this aftn-eve than is progged. Just got a look at the new GFS, and it may be accounting for the stronger kinematics as it has a deeper system over the northeast quarter of KS by 00Z (984mb)

Edit, Just saw the 15Z ruc... it has picked up on this, showing "breezier" mid-level flow. It holds the surface low over Salina KS at 00Z and is down to 983mb!

 

[Joey Ketcham]

I'm already in my Target area... my house in Pittsburg Kansas. Very impressive setup.

 

[Bart_Comstock]

I'm stuck in my target area (my house), of course there would be this nice of a setup only weeks after my chase vehicle throws a rod. Plus I have to find someone to cover for me at work. Anyone need a chase partner in the Bentonville, Arkansas area? If so send me a PM.

 

[Glen Romine]

I think Bill's discussion above is pretty reasonable, but I prefer a (virtual) target in extreme SE OK. Nice looking westerly surge at the surface, secondary warm front with > 60 sfc dewpoints, some clearing skies to help low-level lapse rates and mid-level flow with a better westerly component than in ne OK, where I don't see the shear profiles being favorable in the model forecast anyway. Didn't spend much time looking things over carefully, but thought I'd throw in my 2 cents.

Glen

 

[Bill Schintler]

bullseye MDT risk for Ozarks and pts east to Eastern sections of Norther Ark and Southern MO. w/ attendent 5% region
http://www.spc.noaa.gov/products/outlook/day1otlk.html

Believe this will be where triple point will occur and move east to NE from there

For those who pick their chase targets in the center of the SPC risk area, you have to remember that because the sun goes down at 4:30 these days, much of the severe WX in the risk area today will be AFTER dark - bill

 

[Bart_Comstock]

Also remember they don't call it green country for nothing, NE Oklahoma does have a lot more trees than Kansas and once you get into NW Arkansas and extreme SE Missouri you get into heavily wooded hills (the Ozarks) which can make seeing anything a pain after dark and even in the day.

 

[Jonathan Whitehead]

I think I'm going to call my aunt; she lives southwest of Jefferson City. I love her dearly, but she pays no attention to the weather.

Will be doing the same here, calling my grandparents in NW Ark, Rogers/Springdale vicinity if things get out of hand. I would chase this but if im not going to chase the Nov 15th high risk, then im not chasing this one. One b/c I dont have the money, still building up for next spring and I have hw.

I prefer a (virtual) target in extreme SE OK.

I agree with Glen here on this one. Higher dews will yield lower LCL's and as a previous poster mentioned, the Jayton profiler is showing some significant winds that will be heading into this area.

Just like on the night before the 15th I and other people I know were saying that no matter what happens Memphis is going to have a very interesting day, its just impossible for that city to not experiencing something out of this. Well on this day im saying the same thing for Little Rock. That city going to get slammed some way some how.

 

[Shane Adams]

I'm not chasing this for one simple reason - I can't keep up with it.