4/9/04: FCST: N TX & S OK

[Tony Laubach]

Originally posted by Chris Rozoff
But who knows, I'm almost as insane as a *real* stormchaser.

And I am insane like a *real* storm chaser .. but I guess I'm not stupid, though... bad luck has forced me to withdrawl my name from the hat :banghead: .. on my way home to pick up a check, my car's front end began to wig out on me.. guess I knew it was due, especially after successfully surviving the 2300 miles I put on that bad axel going to Iowa, then down to Oklahoma and back :shock: . Fortunately it happened on Hwy. 6 five miles from my house and not in Sherman, TX 650 miles from my house..

In any case, with less than 4 hours before my departure time, I am going to have to take a sideline seat for this one (as it snows on me here)..

Best of luck to everyone, I will wear the lucky #81 jersey for everyone heading down! It's still early in the season, so I won't spit too much fire for this one :angryfire: .. glad I'll have some synoptic time to try and get this fixed and ready for when the real action starts!

Watchin' for ya!

Tony :cry:

 

[Anonymous]

I think tomorrow will be real borderline, but I will be out. I am thinking somewhere south of Chickasha and Pauls Valley in between 44- and -35, as tomorrow pans out I will decide 35 or 44.

 

[John Cameron]

If any of yous guys are within 45 miles of SPS, you can hear the audio portion of our signal @ 87.7 FM.

Best of luck to anyone. If you see a tornado in the area call 322-1153.

 

[Peter Wharton]

Re: Some Thoughts on the 18 Z eta

Originally posted by Chris Rozoff
Early in the year, a year that potentially looks miserable for chasing from a persistence forecasting standpoint. (i.e., Jupiter's redspot situated over the western united states)
Chris

Can you please explain this comment - for a relatively novice storm analysis guy - how did you arrive at this view?

Cheers,

Peter

 

[Kevin Scharfenberg]

The convective system in the panhandle down into southeast NM is resulting in a large cold pool at the surface. The 00Z temperature at AMA was 48, as opposed to the progged temp of 65 by the 00Z eta. To me, this does not bode well for tomorrow's chances.

More after I have time to digest the 00Z data.

 

[Jason A.C. Brock]

Hey John

Is that the # for one of the local stations in SPS? If so which one and should I ask for anyone if I see anything interesting? You interested in Tornado reports only?

Jay

 

[Kevin Scharfenberg]

Short version:
Tonight's convection looks disruptive to chase potential in Oklahoma and much of north Texas. Best threat shifting down into the area SW of the D/FW metroplex. Supercells possible, but low tornado threat.

Long version:
The 00Z eta and RUC models have no concept of the cold bubble of air accelerating southeast across west Texas. For example, the 00Z eta says the surface temp in Lubbock at 1am will be 62. I'll bet the house on "colder".

The vort max responsible for this convection will lift ENE into Oklahoma in the morning as it shears out. This will carry the convection east, as the dense cold air in west Texas continues to spread southeast. By morning, I expect a large area of stable air roughly northwest of an San Angelo - Ardmore line.

The weakening shortwave trough and continued strong zonal flow over the terrain in New Mexico will keep the surface low virtually anchored over far NE New Mexico. The sub-tropical air will ascend isentropically over the remnant cold dome. The weakening, shearing and lifting nature of the lead vort max makes me suspect the isentropic ascent will win out over any subsidence behind the shortwave trough, keeping Oklahoma grunged in most of the day.

Farther SW, down toward Abilene, the cold pool will have a better chance to be eroded during the day, as isentropic ascent will be much weaker. If we can keep a cold ridge from anchoring down into deep southwest Texas tonight, the 00Z El Paso sounding suggests the dryline may be able to sharpen up. So I'd look for a triple point to set up somewhere down in the Abilene-San Angelo area.

Storm motion estimates, given a reasonable 00Z eta forecast profile, would take storms toward the east southeast, keeping them out of the cold/stable air. Seasonably marginal instability, combined with shear profiles that are "okay but not that great", make me think widespread/significant tornadoes are not a major threat.

Initial target: Rising Star, Texas.

 

[Bill Hark]

Friday potential

Friday looks interesting but not exciting. On the 00Z eta, there is a nice projection of CAPE up to 1500 through central Texas that extends northward and shifts eastward by 0000Z into south central Oklahoma. SRH is better in central Oklahoma but there is still an area of 200 m2s2 that extends to the south into Texas. The low shifts into the Texas Panhandle with backed surface winds across the Red River Valley by 1800Z. By 000Z, those winds are progged to shift to the SW. Upper level winds are unimpressive. The strongest winds (250 mb) level are south of Texas with only winds of about 60 across northern Texas and Southern Oklahoma. The 500 mb are weaker with winds of 40 across the Red River Valley at 1800 Z and these shift to the east later in the day. I do like the change in wind direction: W,SW,SW and SE for 500 mb, 700, 850 and surface respectively. The CAP should be almost non-existant. I am very concerned about the ongoing convection over the Texas Panhandle that will shift eastward. Although some good boundaries may be formed, cloud cover will retard heating.

Right now, I would like to be staying in Wichita Falls, Texas.

Bill Hark

 

[Tim Vasquez]

I'm bothered that the MCS hasn't gotten far into OK / N TX, and new development persists in far E New Mexico. This is really beefing up the cold pool. MAF radar loop at 06Z is showing the outflow surging south like there's no tomorrow. If the MCS keeps putzing around out west then we'll be looking at sucky NE-SW boundary orientations to boot.

Tim

 

[Lance Maxwell]

Ya, tomorrow looks like total suckage. Looks like I will pass up chasing in favor of going to morning class and then heading toward the D/FW area in the afternoon to see the parents for Easter. Who knows, I may have just as good a chance of seeing something heading down I35 in the afternoon as I would if I were out chasing all day.

I will make one last check of the models in the morning to make certain of a final decision. However, attm, I find it hard to believe that anything besides some spotty (only decent) cells will pop tomorrow in lieu of the morning (and perhaps noontime) MCS.

 

[Kevin Scharfenberg]

The good news is, the MCS didn't blast a cold pool too far south. The bad news is I don't think it matters. The 6am surface map shows 60 dewpoints confined well south of San Antonio, and there is no mechanisim that far south to start moving the moisture farther north. Every consecutive model run has shown weaker and weaker wind fields over Texas, and this morning's nearly calm winds suggest it is coming to pass. I think the 09Z RUC has the right idea, and dewpoints will struggle to break the mid 50s in central and northern Texas.

I was looking forward to chasing today, but now it looks like a no-go.

 

[Mike Umscheid]

I like the I-35 corridor south of DFW, near Waco. Straight west to east 500mb flow around 35 with decent lower trop convergence on the dryline in this area on nose of richer moisture advecting north. Current obs this morning (11z) certainly don't look promising for moisture, thus a south adjustment, I think, would be necessary to realize 2000+ surface based CAPE. Should be a decent push on the dryline (enhanced convergence) around the US-84 latitude. Gatesville to Waco is my pick.... hope it works (I'll be chasing on the D2D today...)

Mike U

 

[John Cameron]

Originally posted by Jason A.C. Brock
Hey John

Is that the # for one of the local stations in SPS? If so which one and should I ask for anyone if I see anything interesting? You interested in Tornado reports only?

Jay

that # gets you direct to the channel 6 WX center. I would limit calls to promising wall clouds and tornadoes only. Just say who you are and mention Stormtrack.

 

[Kevin Martin]

My Analysis

My newly developed Math Analysis for Severe Weather shows a marginal day today. with higher risk being hail, and lower end being tornadic. here is my math analysis. I call it Martin's Law of Weather,lol.

FORECAST ANALYSIS FOR THE RED RIVER VALLEY< NORTH OF DFW METRO AREA ON HIGHWAY 35

Dewpoint Forecast shows a dewpoint at 62= 50%
Surface Temperature will be at 70 degrees= 40%
Low Level Jet inflow at 850mb will be at 20-25 knots= 25%
Surface Moisture Carrying Wind= 100%
700MB Dry Air Carrying wind= 100%
Upper Level Jet Stream will be blowing at 50 knots= 0%
500MB vort values= 20%
CAPE= 50%

Probability of Severe Thunderstorms is 55%
So with that 55% it corresponds with my charts on........

Severe Thunderstorm Risk.
NO SEVERE RISK(NONE)
GREEN ALERT(LOW)
YELLOW ALERT(SLIGHT)
ORANGE ALERT(MODERATE)<---
RED ALERT(HIGH)
PINK ALERT(EXTREME)

Type of Event.
NO SHOWERS
SHOWERS
NO THUNDERSTORMS
WEAK THUNDERSTORMS
STRONG THUNDERSTORMS
SEVERE THUNDERSTORMS<----
HIGH RISK SEVERE THUNDERSTORMS

Thunderstorm probability is 60%.
no Thunderstorms expected.
Slight Chance
Chance
Possible<---
Likely
Run For the Hills


HELICITY= 100-150 Weak Torandoes Possible F0 to F1 Damage

Hail values.

50%
100%
50%
50%
100%

added together is 350 or.

Greater than 3/4 inch hail possible!

And now for my discussion

Forecast Discussion.

Surging moisture from the South will result in very high dewpoints in the forecast area today. A dryline will move through the region setting a boundary for Severe Thunderstorms to develop. With CAPE values expected to be in the 2000-2500 range, expect explosive developments. Large Hail will be a large factor, and perhaps the largest threat of the day with these storms. Wind fields don't really show all that much in Tornadic activity, except for Oklahoma City, Northeastward towards Tulsa, Oklahoma, where the highest helicity values will be. If a tornado forms in any of these storms, it will have to be around that area, leaving Northern Texas under a very slim, to nil chance of a tornado, so im leaving that wording out. 500MB chart also shows no signs of fast storm movement, so strong damaging winds within the storms, and bow echo thunderstorms will not be a problem.

Main Concern: Large Hail. Isolated Tornado from Red River to Tulsa, Oklahoma.

MARTIN

Please do check out a map I develop a day before the action hits, and daily updated. My tornado watch, and severe thunderstorms watch, and the very first Tornado Intensity Forecast Map. Should help some of the chasers this spring if they visit the site.
check it out here.
http://www.powow.com/orbiteradds/severe.html

Kevin Martin

 

[Shane Adams]

Just completed a detailed analysis of ETA/GFS/RUC data.....and I now have two targets, lol. The first one is the area from Ardmore (my original target town) to Ada, OK. This area's pros include close proximity to the front (and subsequently the best backed surface winds), enhance local helicity, and the help of a decent 850 speed max moving through the area by 21Z. The cons of this particular spot are a potentially severe lack of moisture, bad chase terrain, and the possibility of clouds/ongoing precip messing up insolation. Hope I used that term properly, that's a big word for me :lol:

My second target is Brownwood, TX. Pros of this area are a much better fetch of moisture (especially at h7 per ETA), higher temps, and (if it doesn't mix out too much) the forcing of the dryline (or surface trough as nealras would have it) Cons include a lack of surface veering (although any decent storm could back the winds locally), and (per RUC) an indication of subsidence in the wake of (I guess) previous precipitation. UVVs looked good at h5 on the ETA & GFS, but the RUC has a complete void in this region, which to me says "subsidence." But I'm not meteorologist.

I'm leaning towards southern/SC Oklahoma and points east, betting on the front to jack helicities on any storms. However, I'm not commited to either spot at this time. I'm sure the 13Z SPC outlook will heavily influence my thinking, if they're anywhere close to what I've come up with.