5/23/07 FCST: TX/OK/KS

[Bill Schintler]

Chase target for Wednesday, May 23

Chase target:
Woodward, OK

Timing:
Storm initiation 3 PM CDT.

Discussion:
A CF across NW OK will begin to retreat slowly NWRD today as SFC low pressure organizes in ERN NM in response to a vort max rounding base of H5 trough. Deep-layer shear will increase to 50 kts as trough slowly shifts E while backing SFC flow should result in SFC-3km SRH’s to 300m2/s2. SFC dewpoints of 65-70F with a 100mb deep moist layer beneath steep mid-level lapse rates will result in MLCAPE’s to 3000J/kg.

[FONT=&quot]- bill[/FONT]

 

[Chris Hayes]

Target for today is from Woodward Oklahoma to Canadian TX. RUC computer model forecasting CAPE values in excess of 3000, closing in on 4000 in the eastern TX PH near Canadian with 0-3KM helicities as high as 350 across the target area. A decent cap should hold down storm production for a while, but expect explosive development in the target area after 3pm. Pretty decent chance of a few isolated supercells across the TX PH today with some strong tornados possible.

 

[Jason A.C. Brock]

As I am sitting here waiting for some detailed GPS maps to load .I am surprised to see how far the front made it this AM but NWS continues to believe it will eventually retreat North. Even if it doesnt I will be headed towards the Pampa area with options to go North etc. While I was loading some chase gear it actually lightly rained here in Wichita Falls I am guessing from WAA showers popping up so there is some good moisture going on. I do hope some of this cloud cover erodes Along and SE of the front. I will be departing no later than 11am and I may stop for a quick data check at the rest stop on 287 near Hedly for some internet. Here in Wichita Falls we have 72 over 65 on temp. and dew.
Area I am liking is Woodward Canadian and Pampa areas. However if the front does go further North than expected Dumas to Guymon should be decent starting points...or if the front is further South Amarillo over to Shamrock could even be a possibilty. The ride home will long and storms nipping at our heels. It may give some good lightning opputunities however after dark. No reason to stick around and stay the night as tomorrow looks very marginal and further SE but things could be in my neck of the woods on Thursday for anything that did happen locally. I am sure ill be sleeping in after this one tho. ;-)

 

[Donald Giuliano]

It appears that this system is indeed slower than last night's model runs, which has tempered my enthusiasm for this setup somewhat, at least during the daytime. It still looks amazing around/after dark, especially if precip fires in western OK like the NAM is forecasting. Regardless, still heading out today as it looks pretty darn good, especially if we get some 00Z LLJ magic.

 

[Eric Flescher]

slower than last night's model runs,

I am curious to know your prognosis that
"It appears that this system is indeed slower than last night's model runs"
what makes fast better ?
I can guess but interested to know


**

It appears that this system is indeed slower than last night's model runs, which has tempered my enthusiasm for this setup somewhat, at least during the daytime. It still looks amazing around/after dark, especially if precip fires in western OK like the NAM is forecasting. Regardless, still heading out today as it looks pretty darn good, especially if we get some 00Z LLJ magic.

 

[Donald Giuliano]

I am curious to know your prognosis that
"It appears that this system is indeed slower than last night's model runs"
what makes fast better ?
I can guess but interested to know


**

Sorry, should've been more specific...I was referring to a previous post where I expressed those concerns last night, of course that's about 15 posts back by now, should've realized that.

Anyway, I'm primarily concerned about the best low-level shear being out-of-phase and not arriving until after dark as the 850mb low deepens and shifts northeast into western KS. Hodographs look mediocre at 00Z, but by 03Z are really nice. This is likely partly due to the nocturnal LLJ, and partly due to better dynamics as the 850mb low deepens. However, I think it possible that the nocturnal LLJ will be able to compensate before dark as it strengthens around/just after 00Z ahead of the best dynamics, so I'm still excited about the possibilities this evening even if the best shear dynamically doesn't arrive until later. Otherwise we might be left to just chase more night-time tornadoes...cool and all, but I want my sunlight dang it!! There's only so much one can see at night.

**EDIT: A second concern would be initiation holding off until later due to weaker forcing, but I haven't looked closely enough at that to have much of an opinion one way or another.

 

[Tim Marshall]

TARGET: SPEARMAN, TX TIME OF DEPARTURE: 1PM - In Woodward this morning. I like the target from Pratt, KS to Spearman, TX. Interestingly, the RUC backs up the tail end of this front so that the panhandles become the play today. Figure to get to the southwesternmost cell along the front as storms will seed each other (like yesterday). TM

 

[Brian Swiatowy]

Hmmm...interesting that the front really hasn't made much progress back north yet. But then again, we've had clouds a little while longer this morning and that will slow the shove back north. Just looking initially at the 15Z RUC there are two things to note...one is the the rapid transition to southeast winds across most of the Texas Panhandle by this afternoon. I think that's a bit overdone. Secondly, the RUC still puts the dryline east of I-27. While it may be close, I would expect it to be just west of I-27 by mid afternoon. The 1630Z update to the Day 1 will likely reflect these issues with the MDT risk pushed farther south (again) to include the I-40 corridor (probably to around Claude to Wellington, TX on the southern fringe) then curling up into northwestern OK. With that said, I agree with Matt that the I-40 corridor will probably be the northern fringe of the chase realm in the central TX Panhandle then going up into the northeastern TX Panhandle maybe along and just north of U.S. 60...but also including the area off the Caprock in the southeastern Pahandle if a storm gets going south of I-40 and along I-27.

 

[Paul Knightley]

Extrapolating the ECMWF from its start position (which is slightly wrong), and incorporating the other models, I think we'll head to the Guymon - Perryton area - in Garden City just now so will be leaving very soon.

I think the front should be in or very close to this area around 21-00Z, and the dryline push in from the SW won't be far away.

Good luck everyone, and stay safe.

 

[Chris Hayes]

Looking at the updated RUC forecast on the COD website, the parameters coming together over the central TX PH are insane for severe weather with a breakable cap, cape values in excess of 4000J/KG and 3KM helicities of 200-450 over a large area centered on the Amarillo area. Again, I'm new at forecasting, but it appears to be a crazy and long day/night in the PH.

 

[Fritz Kruse]

Siggy Tornados Possible TX Pan

Strong shortwave trough now coming into northern New Mexico with
attendant pressure falls. With these falls the moisture should be sucked
rapidly northward into the northern TX pan.

With 50 knots coming out with shortwave at mid levels on top of the deep
returning moisture and CAPEs forecast around 4000 J/kg looks to be a possible
significant tornado event.

 

[Jim Bishop]

I'm really liking the area from just east of Amarillo to Panhandle/Pampa to Perryton (basically the central & northeastern Texas Panhandle). That area should light up along the front early this evening. The shear alone supports supercells with tornadoes, but any storm that can ride the boundary will have even higher tornado potential.

What's interesting is the models deepen the low after 00z, and in response 850mb winds increase from ~30 knots to 40-45knots. I see really good tornado potential in the hour before dark and thereafter.

Good luck to chasers out today. Looks like I have to sit this one out.

 

[Shane Adams]

We're in Woodward, following the slow northern progression of the front. Honestly having a bit of trouble picking out the surface low but we're planning to latch onto it like a mother's teet and ride it north to whatever end.

It's soupy out here.

 

[Donald Giuliano]

Definitely liking the 15Z RUC, which bumps the shear back up a bit. Vort max looks to be on track to be near the four corners near 00Z, which agrees with current progs.

Anyway, about to head out of here, and will probably target Pampa, TX, given that the dryline appears to be setting up pretty far west. The models seem to want to initiate things fairly early, which may well happen, but I'm not too excited about the tornado potential until closer to/after 00Z.

 

[Michael Johnson]

First post here...so I thought I would say hi.

It does look good for a good chunk of the central and eastern TX Panhandle this aftn/eve. Looks to be a long night at the office. Feel free to let the NWS know what you see. Any real-time info is greatly appreciated, even though you might not get that impression over the phone. It really does help.