3/28/11 FCST: TX

[Doug Drace]

Been spending my time off work today looking down the road to see if anything looked interesting in the near future and found this. Monday 3/28 appears to have some interesting features coming together in the NW Texas area, generally speaking ATTM from near Childress, TX southward to Abilene. I am by NO means an expert at forecasting as some of you are, but I know enough to look down the road and end up getting myself where I need to be come chase day with good confidence. With all that said, the afformentioned area I spoke of, IMO, looks decent enough 4.5 days out that I felt it was time to start a thread on it. A couple different GFS models I look at are painting in a nice stripe of 1500+ J/kg of CAPE from South TX up into the Abilene area and points north into NW TX near Childress. There also are decent DP's nearing 60, along a fairly sharp Dryline which extends the length of the Eastern TX Panhandle down into South TX. This is also supported by a nice shot of Thete-E injection the length of the DL up into the Eastern TX Panhandle. There also appears to be a nice chunk of Mid-upper level energy rounding the base of a decent Trough from 700-300mb, with winds consistantly increasing with height. Forceasted Surface Temps dont look bad either in the Mid 70's range. The best Upper Support certainly looks to be north of I-20 in the region, and Climatology also is favorable to this general area in the 3/28 time frame...ie: (3/28/07...Although that day was concentrated more into the Texas Panhandle), not that I am saying this is a setup as awesome as that ending up being. GFS does have a couple areas of Precip broke out by 0Z from Childress south. If the models maintain or even shift things a little NW it would still look quite promising to me...I absolutely Love chasing out west...as I know most everyone does I look forward to hearing some opinions from some of you more experienced mets on here.

 

[Skip Talbot]

Some absolutely beautiful forecast skew-t's and hodos down in TX on that GFS run:
http://www.twisterdata.com/index.ph...iew=large&archive=false&sounding=y&sndclick=y

At face value my concern is that the instability axis is pretty narrow where the best shear to the north is, and there is some lingering inhibition being plotted at 0z even though the cap opens earlier. The GFS is plotting precip at 0z, but updrafts might be struggling a little against the lingering cin and modest instability. Still a beautiful setup though... if it verifies...

And that's the real kicker. This is the first run the GFS has showed a solution like this for Monday. I'd love to see it plotted again on later runs, but I don't put any stock into solutions that magically appear out of nowhere for the first time. Lately, the GFS has also been consistently overdoing dewpoint forecasts and pushing the warm front too far north at the 108 hour time frame. When the NAM comes into range the next morning its a completely different story with the dewpoints and warm front much further south. I fear we may see the same thing here tomorrow morning, and what could have been a localized but awesome chase event, could turn out to be a non event as the GFS may just be teasing us again.

 

[Doug Drace]

Hey Skip Thanks for your input! You certainly were one of the guys I was hoping for another opinion from I agree about this thing popping up out of nowhere, the only other run that I had seen even remotely close to this sweet looking setup GFS is currently putting out, was a couple days ago. On Tuesday the run for this day (might have been Sun 3/27) showed a WF feature generally around I-20 with a DL intersecting near Abilene and some pretty decent CAPE, along with precip breaking out near the WF....then it magically pretty much disappeared over the next couple days runs. I agree if it verifies it could be a sweet setup in NW Texas provided CIN is further removed....and those Hodo's do look really nice!!! Guess time will tell on this one, right now doesn't look like much else for the Southern Plains except maybe a little severe in N-NE TX/SE OK/ARK tomorrow.

 

[Connor McCrorey]

I'm typically optimistic about setups holding in this timeframe instead of vanishing or drastically changing, but the GFS has been so all over the place lately that I really wouldn't count on it. However if it does verify, Monday would be huge in NW TX in my opinion. Those hodographs are gorgeous, and almost 2000 J/kg of CAPE has me drooling! As Doug said, March 28th has been big in Texas before (Fort Worth tornado in 2000, 3/28/07...), even though that really doesn't affect this at all

 

[TimothyCarroll]

I agree with Connor in regards to the GFS being all over the place, but IF it does verify, I see a real potential for a chase from about Vernon to Abilene, Eastward to Ft. Worth to Gainsville / Red river. . . If these models continue the trend they are on, we would have significant deep layer sheer, very good low level inflow, and winds are nicely backed. CAPE's being AOA 2K j/kg, and LI's as intense as -6 to -7 near Throckmorton, TX, 25-30kt 10m SSE Inflow winds, and storm motions to the ENE AOA 30kt's leaves us time to play, as the storm motions will not be too insane.

That is just my basic 5 minute brief run down of what I saw from the models . . . and my $0.02 worth. . .

Detailed Forecast to come with future runs.

We Shall See . . .

 

[Robert Edmonds]

Last I checked the surface low was placed more to the SE. This causes the moisture return to be further SE. While some nice curved hodos and (weaker) shortwave remain, the cap appears more robust. Wait and see if this changes in the next few runs...

 

[Chris Wilburn]

Three consecutive runs of the GFS have shown a favorable chase setup for this day from extreme Southern OK to Northern TX. The lates 06z run has very nicely curved hodographs. CAPE in the area of 2,000 J/kg is forecasted for Northern TX with CINH values actually decreasing with this model run. The area of instability isn't confined to a narrow band like on previous runs either. Dews near mid 60 are also forecasted. I know this is an off hour run of the GFS but it is worth keeping an eye on. It will be interesting to see how the NAM compares. The 84 hours NAM from 12z this morning should be in the timeframe of Monday evening so we should be able to compare the two models here in just a few hours. Anyway that's just my thoughts for this day.

 

[Doug Drace]

Just took a look at GFS this morning for Monday and wow! Also just looked over NAM out to 18Z Monday and what a major difference in the two...not even close right now. The one thing thats keeping me pretty optomistic is that as Chris said, there have been 3 consecutive runs on GFS with basically the same setup...with just a slight eastward push to it from yesterday afternoon. GFS is still putting out some real mouth watering Large Curved Hodo's, and even deeper low level moisture than yesterday with DP's easily 65+ making it into extreme Southern Okla from around Lawton, down into North Tex generally around Wichita Falls to the south through I-20, so its still favorable chase territory. CAPE has increased from yesterdays runs to 2500+ with LI's around -5 to -7. Guess we'll see what the next few runs of NAM put out, cause this mornings run out to 18Z looks like everything would be in deep south Tex...maybe they will come closer together over the next couple days.

 

[Skip Talbot]

Wow, the NAM is actually much worse than I thought it would be:

http://www.twisterdata.com/data/mod...25/12/NAM_221_2011032512_F84_CAPE_SURFACE.png

The models were diverging significantly last night, but I have a tendency to side with the NAM here since its been performing better and plotting much realistic solutions at the 84 hour time frame than the GFS.

The best instability is now limited to extreme southern TX. The shear is so light down there, and with significant capping also forecast, I don't see much of a chase potential at all if the NAM solution verifies, except for maybe an outside chance for south TX locals to pick up something isolated.

 

[Jesse Risley]

The H5 charts on both the GFS and ECMWF per today's 00z runs were pretty similar, though there is the difference in the surface maps with the Euro progging a slight deeper 996 mb surface low over far SE CO at 00z TUE, whereas the GFS has a 1000 mb low shifted slightly further SE during the same time frame. While the NAM's 12z run today may be disheartening, as Skip noted, the 00z GFS and ECMWF are somewhat similar in depicting that broad dome of generous SBCAPE value AOA 1000 - 2000 J/KG nosing into NC TX.

However, the ECMWF is not indicating anything over 1500 J/KG making it very far north of the Rio Grande at 00z TUE, whereas the GFS is far more magnanimous in progging that area of CAPE values AOA 2000 J/KG from Witchita Falls - Denton, extending back towards San Antonio. The hodos on the ECMWF across the same areas that were previously listed from earlier model runs (NC/NW TX) look somewhat similar, with SRH values of app. 250 m2/s2, and favorable directional shear in the lowest 1km, though surface winds on the ECMWF Skew-T profiles are somewhat weaker than what's being depicted on the GFS (i.e., 10 kts versus 15 kts or so).

The models should converge on a more coterminous solution by late weekend.

 

[Doug Drace]

As of this morning this one still has me fairly confused with a huge spread between GFS and NAM. If you go with NAM's solution, there is basically NO chance for severe weather this day...except maybe in the Deep S Tex area...which has been consistant for 2 morning runs now. If you go with GFS, it has backed off the northward return of Deeper 65+ DP's and best MLCAPE returning all the way into extreme S Okla, however this mornings run still brings in 60's DP's, in a tongue from S Tex through I-20, then narrows considerably as it moves north toward Seymour, Tex. Today CAPE slacks off a little from yesterdays run in NW Tex which was pushing 2500+ to todays run anywhere from 1000-1500 J/Kg, then gradually increasing closer to 1500+ near I-20 generally around Cisco and Breckenridge on TwisterData's GFS. On Dupage's GFS, MLCAPE is still really nice around 2200+ in the same area...not a chase crushing change overnight. Dispite the somewhat suckier run this morning, the mouth watering Large Curved HODO's from I-20 into NW Tex are still there and the SPC has put out a "See Text" for West Texas into NW Texas on Day 3, which leads me to believe they do have some confidence that the GFS isn't completely out of wack on this. Who knows right now...but im pretty sure there's gonna be something decent pop up monday, even if its 1-2 Isolated Supercells. Right now, if today was monday I would be headed out to the I-20 area generally around Abilene...that area always puts out sweet Isolated Supers. The NAM and GFS have both been very consistant on this one so far....consistantly DIFFERENT! Lets just hope the GFS wins out, or we can at least split the difference between the two...in favor of the GFS!!!

 

[Doug Drace]

Patience has not always been my best forte. Just before I went to work yesterday afternoon I took another peak at the latest GFS & NAM, and was quite disapointed to see the GFS had finally trended more toward the NAM after 3 straight mornings of a very sweet setup from I-20 into NW TX. However this morning things have somewhat modified back toward what GFS was showing...this time with the NAM...though still not as breathtaking a setup...and in a somewhat "splitting the difference" kind of way. Yesterday I mentioned I could see myself heading down to the Abilene area, and after a look at both models this morning, I can still see that happening, a little SE of there, say generally on an Abilene to Coleman line. NAM is certainly stingier with moisture return, DP's only in the 50's, where GFS as always has been the case, is bringing a tongue of 60's into that same area. CAPE is around 12-1500J/kg NAM, 15-1750 GFS. The HODO's in that area continue the large curvature, on both NAM/GFS, so that part also keeps hope alive. SPC also continues with there "See Text" area from yesterdays Day 3. Probably going to be an elevated storm or two if NAM verifies, possible surface based Supercell if GFS wins out. For some reason I just can't seem to shake the idea of chasing tomorrow afternoon....might be wish chasing this...or might be that complete lack of patience I mentioned earlier. If I haven't learned patience after 15 years of chasing, it's probably not going to happen now, and I like that area for a tiny possibility tomorrow.

Skew T/HODO from NAM/GFS near Coleman, TX 3/28:

 

[Brandon Sullivan]

Still some major synoptic scale differences in the GFS/NAM in placement of the dryline, and some other mid level features.. Both models do show some good kinematics for supercells, and enough low level shear for tornadoes.. However, we would definitely need the GFS moisture to come to reality first.. The SREF tends to side just a bit more with the NAM in regards to moisture return..

One issue that definitely worries me is the EML plume present across the area.. With weaker instability, and no huge UA forcing to set the show off, could see a sun tan afternoon.. Will have to watch to see what the Hi Res models say later, and the other models this evening.

 

[Connor McCrorey]

Unfortunately, it would appear that the RUC is closer to the NAM's solution, with 60+ Tds confined to S TX at 18Z tomorrow. The GFS has the 60F isodrosotherm all the way into central TX at the same time, so while I would certainly chase if the GFS were to verify (somewhere near Abiliene), I'm not at all confident that will be the case.

 

[Doug Drace]

Yeah im liking this a whole lot less with each run. The trend keeps on with the NAM winning out, so looks like another long range GFS bust. Don't think we're gonna chase this one now, a whole lot of fuel with likely not much reward. So i'll check it in the morning, then start hoping the new GFS run that popped up seeingly out of nowhere for this coming saturday can manage to move in the right direction for once this early season.