4/01/06 FCST: KS/OK/TX

Descent 1000 mb surface cyclone looks develop across the central/southern high plains Saturday and set up a nice dryline through sw/sc kansas south through western oklahoma/eastern Texas panhandle and into north texas per 0z Nam model run, GFS Proggs surface cyclone slightly deeper at 999 mb. Nicely backed surface winds(especially east of where the dryline arcs back northwest) should result in more than sufficient low level shear supportive of tornadoes, and mid upper level shear is at least supportive, and in favorable orientation of the surface boundary to make supercells the favored storm type. Lots of instability(CAPE upwards of 2000 in some areas of western oklahoma). so everything looks great if storms can manage to initiate that is. I say that because cap still looks strong across much of the area. If we could speed up the progression of the upper trough just a bit this problem could be dissolved but I dont know if this is going to happen especially considering that if anything the models have trended to slow systems down a bit lately. 700 mb temps around 5-6 are on the brink of clear sky bust for this time of the year, and there is also a strong possibility that there will be some cirrus clouds overspreading the target area through initiation. So it appears to be some what conditional at this time as to wheather storms can develop but if they manage development they would be of supercellular character and have the potential to priduce tornadoes for the reasons stated above. Surface moisture appers favorble especially from Kansas border sout with 60 degree dewpoints up to atleast the Ks border(possibly further) progged by the 0z Nam.

All in all looks good but initiation again appears to be the main problem

Thoughts?
 
I agree that initiation will be the issue with this setup. But storms should fire across Northwest Oklahoma given the vort max moving through Southwest Kansas and a upper jet streak nosing into the area. It will be a late initiation, probably 4 or even 5pm. Curved hodographs support supercells with a few tornadoes given low to mid 60 dewpoints. I like the backing of both the 850 & surace winds along the suedo warm front near the Kansas border.

Being a Saturday I plan to be up there for this event!
 
Based on fair amount of agreement in the models im going MODERATE for Saturday for NW. Oklahoma and W. Kansas
Here is my projected outlook:
[attachmentid=56]
 
My initial target for my "virtual" chase will probably be in the Woodward area - certainly expecting somethin between Woodward and DDC. I wonder whether it'll actually turn into a Medicine Lodge chase?! That place often seems to be a great target in WF/dry-line set-ups.
 
My initial target for my "virtual" chase will probably be in the Woodward area - certainly expecting somethin between Woodward and DDC. I wonder whether it'll actually turn into a Medicine Lodge chase?! That place often seems to be a great target in WF/dry-line set-ups.
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I agree with Woodward as the right target. As far as now I see something like a dry line bulge just out there. From there I would move toward Harper County KS that it's perfect with this synoptic(similar to may 12 2004)
 
Medicine Lodge/Coldwater is my iniital target, as well. Hadn't thought about the similarities to May 12, 04 mentioned in another post -- this stuck me as a "slightly south of there" setup. It'll be interesting to see how the outlooks evolve over the next 24 hours.

My initial target for my "virtual" chase will probably be in the Woodward area - certainly expecting somethin between Woodward and DDC. I wonder whether it'll actually turn into a Medicine Lodge chase?! That place often seems to be a great target in WF/dry-line set-ups.
[/b]
 
My initial target for my "virtual" chase will probably be in the Woodward area - certainly expecting somethin between Woodward and DDC. I wonder whether it'll actually turn into a Medicine Lodge chase?! That place often seems to be a great target in WF/dry-line set-ups.
[/b]
I agree on this one, an area between Dodge City, KS and Woodward, OK looks great to me! I would start in Woodward and then moving north towards Dodge city along the dryline. SPC issued MDT risk as well.
 
The setup looks better than yesterday, IMO, mainly because both GFS & NAM fire convection along the dryline across Southwest Kansas/Extreme Western OK. The NAM is probably firing convection since it indicates slightly cooler 850 temps. Both models continue to indicate a vort max ejecting into the Texas Panhandle and Southwest Kansas by 00z Sunday. From IR satellite I don't see a cirrus deck downstream to screw things up. Large scale acent with the upper jet streak, forcing from the vort max, and forcing along the dryline coupled with daytime heating should be enough to break the cap across Southwest Kansas/Northwest OK/Northeast Texas Panhandle. I'm still skeptical about convection firing further south across Southwest OK, but it appears more likely than it did yesterday. I don't want to flirt with the cap not breaking, so prefer to be around the large scale forcing.

The shear profiles are indicative of classic tornadic supercells with hodographs supportive of tornadoes. Tomorrow looks good and I think there will be tornadic supercells. My intial target is south-southwest of Dodge City near Meade, Kansas.

Game on!
 
Based on this morning's forecasted BUFKIT profiles from the NAM and GFS, I believe the corridor between Alva, OK and Enid, OK shows the most promise regarding tornado potential. First of all, the cap becomes completely eroded wrt surface based convection by 23Z (yielding CAPE values in excess of 2500) so there will still be about 2 hours of daylight left for organization should it take that long for initiation. 0-3 km forecast hodographs indicate significant turning in the lowest layers, and 6 km shear vectors of 40-45 knots oriented roughly WSW will be supportive of supercells. 3 kilometer CAPE values ~125 indicate strong low-level buoyancy and should act to increase tornadic potential.

That being said, I have a lot of stuff to do this weekend so I will not be chasing unless something makes its way to my doorstep. I am rather excited about the way SPC has significantly increased their interest in this event even wrt yesterday afternoon.
 
Right now I am planning on heading out of Wichita at 9AM for an initial target of Woodward. I plan on fine tuning the forecast from there before selecting my final target.
Everything seems to be coming together nicely. The 12Z runs have helped put my fears of a blue sky bust to rest. I am a little worried about getting good moisture all the way up to the warm front. The NAM shows a nice curved hodograph for Woodward by 00Z with CAPE >1500. Deep layer shear isn't to great until the mid level jet streak comes in later in the evening, but with shear AOA 35tks during the time period when storms should initiate, we should be just fine. I will probably play the dryline just South of the warm front, but I also like the Altus area in SW Oklahoma and I may get lured down there. The warm front area seems a little more appealing IMO because anvil level SR winds should be a little more favorable for classic supercells (5km SR winds appear favorable for tornadic storms throughout the warm sector). And god bless the slower storm motions tomorrow. I had all the fun I can take trying to keep up with those storms yesterday. 20--25kts seems stationary after that fiasco.
 
Moderator Note

Keep in mind the FCST rules:

(3) Prohibited content. Users may NOT post the following:
* Weather bulletins and forecast images, except as brief excerpts, in moderation, and with an explanation of their meteorological relevance;
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Try and avoid the: "Yes, I like Woodward as a target too" type posts. If the post contains no meteorological content, it probably shouldn't be posted at all. What would be ok is writing: "Yes, I also like Woodward as a chase target, but for the same reasons (list out what other people posted and/or add additional insight)

Aaron
 
12 UTC 12km WRF-NMM Central US Window run from this morning, available from this link:

http://www.nco.ncep.noaa.gov/pmb/nwprod/an...2/model_l.shtml

shows quite a bit of morning convection in E TX Panhandle/W OK from the 700mb Omega and 500mb Vorticity fields for tomorrow. The activity pushes into E OK/W AR by afternoon, and more convection fires along the dryline in W KS/N TX Panhandle by 00 UTC on 02 April, with further development with SWD extent into W OK/E TX Panhandle between 00-06 UTC on 02 April. Also, it appears the wind fields from the WRF run are weaker than the 12 UTC NAM run from this morning.

It seems the WRF is picking up on some of the discussed concern tomorrow, i.e., recover of boundary layer from overnight/morning convection, but appears to rebound quite well. The WRF agrees with Jim... afternoon sfc based convection initiates first with large-scale forcing across W KS/OK Panhandle/N TX Panhandle and then erupt with SWD extent into W OK as cap erodes. As highlighted quite well in Mead's 1730 2-Day Outlook, our old friend cirrus canopy might make or break tomorrow's promising setup.

That morning satellite image has been the subject of many a nightmares for me, and probably will be tonight for crews heading out tomorrow :)
 
i would be worried for folks not for us though as in a good
chance day;) but for property damage in south central/ southwestern
oklahoma tomorrow, looking at ehi index values across central ok of
near 4.5 and over 6 further into southwest ok, not to take away from
northwest ok but i think a area in sw ok from altus,ok to chickasha,ok
to norman,ok and north of a line from wichita falls,tx to healdton,ok
to just n of ardmore,ok to ada,ok i feel this area is best prime for
a possible tornado outbreak tomorrow, also this area from sw ok
into central ok by 0z has helicity values of near 350-400 tomorrow
evening. so bottom line i wouldnt discard to idea of nw ok totally
but i think best area of violent or possible large tornadoes forming
will again be in southwestern, southcentral ok and parts of nw tx
for saturday.. my guess on the day 1 to be issued early tomorrow
morning would be an upper end mod risk for my above mentioned
area i do feel mod risk could go as far e as i-35...

Todd Rasmuson
 
I think that there is a good chance that you chasers lucky enough to be able to chase on the plains tomorrow are going to get quite an outbreak. It appears to me as though there will be violent tornadoes in western Oklahoma. To demonstrate why I think this way, I have posted two forecast sounding texts links below.

0z Forecast Sounding Text

Altus, OK
Woodward, OK
 
00 UTC 4.5 km WRF NMM with no CP scheme used by the SPC...

http://wwwt.emc.ncep.noaa.gov/mmb/mmbpll/cent4km/v2/

strikes out with convection currently ongoing in the TX Panhandle, and unlike it's KF-scheme counterparts, does not have nocturnal convection at all during the simulation. Instead, it lights up the dryline like Christmas Eve at the Kranks with initiation coming at 21 UTC tomorrow afternoon, then consolidates the individual discrete cells into a line that moves across OK tomorrow afternoon. The WRF picks Woodward, OK and Pampa, TX as initiation winners.

Unfortunatley, this model runs is fast on its way to the trash can. Seems like the coarser-grids from the ARW and NMM may end up handling the activity developing near LBB better.

At least we get a glimpse at what life would be like tomorrow without a cirrus canopy! ;)

EDIT: SPC 1 Day highlights 21 UTC as intiation time and the transition to a linear MCS that the WRF picks up on.....gangbusters! Good luck to everyone out tomorrow!
 
Well, everything seems to be coming together rather good. Warm front is starting to make its way back north with tds already into the mid 60s south of the front. Still dry here in Booker with a TD of 36. My only concern with Saturday is the canopy of high cirrus clouds. I do believe that the afternoon sun will start to erode this deck around noon or so. With CAPE around 3000, TDs in the mid 60s, and exellent low level shear, tornadoes are likely, if we can overcome the cap.

My target now is still here at my house/town in Booker, TX(Northeast TX Panhandle) Really hoping that storms can isolate themselves and not become linear. Good luck to all that chases. Look for me in a Blue Chevy S-10 Pickup, with a lot of antennas on top.
 
I think we'll not no thinking about it I feel very strongly later today we will
have a TORNADO OUTBREAK across the oklahoma & texas, looking
over the latest, new spc day 1 outlook feel strongly this is gonna turn into
a high risk day. further more i STRONGLY feel areas along I-44 SPS TO LAWTON
TO OKC need to watch out, spc feels stuff will fire at or about 2100 BUT i
feel storms left over from ongoing storms in nw tx will die out over extreem
nw tx into swrn ok near sps to lawton and will leave discrete outflow boundrys
this area has gotta be closely watched for the threat of LARGE VIOLENT TORNADOES
cant put this wording any stronger but not to send mass panic but in confrence with
several other chasers on here we are in feeling this could be another 5-3-1999 setup
of when that f-5 tornado hit moore,oklahoma. rightnow iam most concerned
with extreem swrn oklahoma, i'm thinking of targeting somewhere near lawton
and have i-44 to go on, becouse i think the cells that form over sw ok have a
real threat of putting out very dangerous, violent, long lived tornadoes
through the afternoon,eve hours...
 
I have to agree with Todd, this setup is looking very similar to 5/3/99. Forecast MLCape values for the Mod risk area have gone up in the last couple of outlooks now estimated to be around 3000j/kg. That seems pretty impressive for this time of year. Lawton would be a fair target, but I don't think OKC is totally out of the woods on this one. I'm foreseeing a very volatile and busy day tomorrow. Is a High risk out of the question? I don't think so. I'm actually somewhat suprised we aren't already seeing a high risk with some of the wording that has been used on the latest outlook. Best of luck to everyone and pray safety for those who live in the bullseye this time around.
 
Before we start crying that F5s are going to hit major metro areas, I think we should be a little more cautious. I can't (nor shouldn't) tell anyone what to say, but just think we could be a bit more cautious. Some of us said similar things yesterday (3/29) and that event was largely a nonevent for most of OK. If there's one thing about severe convective forecasting and tornado forecasting, it's that forecasts are extremely difficult, especially for high-end events. There are always failure modes, especially if you take model output exactly as is. Extreme events (such as violent tornadoes) are extremely rare for a reason, and it's not necessarily because models don't forecast environments/setups that appear to favor them. If you look at most chase years, there are usually at least a few setups that look to be favorable for violent tornadoes, and few of those pan out.

I'm still undecided on a specific target for tomorrow. It almost always seems like the area east of the sfc low near the warm front is a good choice, owing to winds that tend to be more backed in that area. However, current model output would lead me to southwestern OK and adjacent areas of TX, where seasonably high Tds will be juxtaposed with strong low-level shear. The NAM is depicting some sort of boundary very near the Red River tomorrow afternoon, as evidenced by a change in the surface winds across the boundary and a rather impressive temperature increase to the south. I'm not entirely sure that I'll believe that solution, but it has been persistent for a couple of model runs. What has also been consistent has been the presence of some weak shortwave (ahead of the main vort max) that the NAM progs to be over western OK by 0z (you can see this in the 500mb height contours as well as the vorticity plots).

I think the main potential failure mode tomorrow involves widespread cirrostratus that would limited insolation and near-surface destabilization. As it stands now, the 0z NAM indicates that mid and upper-level RH >80% will overspread the TX panhandle and begin to affect western OK by late afternoon. In the morning, however, it appears that we should see significant sunshine across the target area. Of course, a visible satellite image tomorrow morning will tell all.

As it stands, this more classic dryline southern plains setup look to offer the potential for a couple of strong tornadoes. While flow aloft is not particularly strong, deep-layer shear should be in the 40-45kt range (certainly favorable for supercells given the CAPE).
 
I have to agree with Todd, this setup is looking very similar to 5/3/99. Forecast MLCape values for the Mod risk area have gone up in the last couple of outlooks now estimated to be around 3000j/kg. That seems pretty impressive for this time of year. Lawton would be a fair target, but I don't think OKC is totally out of the woods on this one. I'm foreseeing a very volatile and busy day tomorrow. Is a High risk out of the question? I don't think so. I'm actually somewhat suprised we aren't already seeing a high risk with some of the wording that has been used on the latest outlook. Best of luck to everyone and pray safety for those who live in the bullseye this time around.
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I hope that Todd isn't mad that I reveal that I'm one of those that he has been conferencing with, but I completely, 100% agree with him. I am shocked by the ETA placing 0-1km SRHs of up to 400 m**2 s**-2 in the outlook area with SBCAPE of 2000-2500 J/kg juxtaposed on top. This screams disaster, IMO, along a Woodward to Altus line. I think the Altus area is really where the highest risk for very violent tornadoes exists. A high risk tomorrow would in no way surprise; in fact, I half expect it.

Also, for those of you who struggle with hail cores (I may be joining you Sunday, but that's another thread), the hail outlook from the SPC should probably have you shaking in your boots. :p
 
I hope that Todd isn't mad that I reveal that I'm one of those that he has been conferencing with, but I completely, 100% agree with him. I am shocked by the ETA placing 0-1km SRHs of up to 400 m**2 s**-2 in the outlook area with SBCAPE of 2000-2500 J/kg juxtaposed on top. This screams disaster, IMO, along a Woodward to Altus line. I think the Altus area is really where the highest risk for very violent tornadoes exists. A high risk tomorrow would in no way surprise; in fact, I half expect it.

Also, for those of you who struggle with hail cores (I may be joining you Sunday, but that's another thread), the hail outlook from the SPC should probably have you shaking in your boots. :p [/b]

Where do you see 0-1km SRH of 400 in the target area? Looking at http://weather.cod.edu/forecast/ETA/SP/etaSP_1km_hel_24.gif , I see an area of ?175m2/s2 of 0-1km SRH near and east of I35 near the Red River, which is considerably removed from the dryline target. Other than that, however, 0-1km SRH doesn't look very impressive near the dryline, at least according to the NAM output I am looking at.

On a FCST note, I should say that I love that we have a few 68-70F TD obs in central TX! I see a td=69F northwest of Austin, and a 71F Td in Uvalde (east of DRT). I do wish that the surface flow was stronger, however. It'll take some time to get that true Gulf moisture (>65F td) up into the target area if winds are only 5mph!
 
I think the main potential failure mode tomorrow involves widespread cirrostratus that would limited insolation and near-surface destabilization. As it stands now, the 0z NAM indicates that mid and upper-level RH >80% will overspread the TX panhandle and begin to affect western OK by late afternoon. In the morning, however, it appears that we should see significant sunshine across the target area. Of course, a visible satellite image tomorrow morning will tell all.[/b]

Also some model-to-model consistency between the old NAM (ETA) and new NAM (WRF) in terms of the UL RH fields and the possibility of a cirrus canopy. I think it underlines a very important point...theres quite a few unresolved questions and uncertainies, particuarly with respect to cloud cover in the warm sector from ascent and convection. Just because a setup looks good on paper, or the SPC goes gangbusters with it in an outlook, doesn't imply its a money-in-the-bag tornado outbreak.

I am shocked by the ETA placing 0-1km SRHs of up to 400 m**2 s**-2 in the outlook area with SBCAPE of 2000-2500 J/kg juxtaposed on top. [/b]

I think you might be referring to 0-3 km SREH. As Jeff showed, the 00 UTC NAM 0-1km SREH is fairly low near the dl, and it's very rare to get 0-1 km SREH that high from a "Midwestern" setup. High SREH in the 0-1 km layer is more reserved for tropical supercell setups with fast flow above the boundary layer and significant veering.

Hoep that helps!
 
I'm liking tomorrow -- albeit the relatively small SRH forecasted by the NAM for tomorrow along the dryline (e.g. 50-75m2/s2 0-1km SRH). The forecast soundings around northwest OK around 21z are quite favorable for slow moving, chaseable classic supercells -- with relatively decent tornadic potential with them (especially with any deviant moving storm which would, of course, increase the SRH). Nonetheless, the combination of very large SBCAPE and deep-layer directional shear for supercells will of course make me wanna chase [I'm still in KS til SUN]. The NAM forecast sounding for Enid, OK at 21z SUN shows a very favorable kinematic profile for supercells -- with beautiful thermodynamics progged across the moist sector (e.g. 60-65 Tds helping to support the 2500-3000j/kg SBCAPE).

--> http://wwwt.emc.ncep.noaa.gov/mmb/mmbpll/c..._hybl35_f24.gif

I wanna be with one of those twin sups in nw OK/sc KS :lol:
 
Morning Guys, it is 6:08, looking over all the latest data, not to pleased with the
morning cloud deck here at my location just n of ardmore BUT RUC is showing
some precip forming near sps by 18z and spreading ne into sw,sc ok by 21z
iam fairly concerned with this in the fact we could get a couple large supercells
with the threat to produce a couple strong tornadoes in this region, for the fact
of overnight convect in this area, which will leave outflow boundrys, so my target
area attm is still gonna be on as lawton area & i-44.... post more in a bit



Todd Rasmuson

EDIT: TAKE A LOOK AT THE EHI INDEX FOR SC, SW AND CENTRAL OK FOR 0Z
SHOWING IT MAXING AT A 7! ACROSS SC OK CLOSE TO ADM OVER TO AROUND LAWTON
VERY IMPRESSIVE!!

EDIT 2: ALSO TAKE NOT HERE AT MY LOCATION AT THE HOUSE JUST N OF ADM
CLEARING SKYS!! SUN IS COMING OUT... IAM EXPECTING A HIGH RISK TODAY..
SPC SHOULD ALSO HIGHLIGHT THE S END OF THE RISK AREA OF SC OK INTO NW
TX, IF ANYTHING BLOWS THIS AFTERNOON IT WILL BEYOND MAJOR, VIOLENT TORNADOES
IN THAT AREA POSS LATER...
 
I disagree with Todd's assement of the apocalptyic - May 3rd - Andover - super-de-duper wedge fest outbreak...

While hodos are certainly quite nice for supercells, I'm just not seeing the low level shear required for a significant wedge fest. Add in uncertainties in the cap strength/storm mode and I'm just hoping to get on some isolated supercells. I highly doubt SPC will go high...

Aaron
 
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