Central/Western Medium-Long Range Discussion

[WhiteoutWX]

Moisture quality finally looks to improve into Texas and Oklahoma starting Sunday through at least Tuesday. Will see if other parameters can finally line up to go with it. This Friday looks rather unimpressive to me at the moment.

[Jim Martin]

12z GFS for Sunday Evening.

[jojo762]

00Z GFS is incredible for Sunday from southern Oklahoma through central Oklahoma into southern Kansas. 

[bjc0303]

3 hours ago, jojo762 said:

00Z GFS is incredible for Sunday from southern Oklahoma through central Oklahoma into southern Kansas. 

Moisture return looked late. also 00z GFS looked potent out into the SE US a day or two later. 

[WhiteoutWX]

1 hour ago, bjc0303 said:

Moisture return looked late. also 00z GFS looked potent out into the SE US a day or two later. 

Yeah I'm not sure I buy mid 60s dewpoints into central OK by 00z Mon but I think somewhere near or south of the red river definitely has a shot. If the Friday system could just get out of the way quicker...man.

[bjc0303]

7 minutes ago, WhiteoutWX said:

Yeah I'm not sure I buy mid 60s dewpoints into central OK by 00z Mon but I think somewhere near or south of the red river definitely has a shot. If the Friday system could just get out of the way quicker...man.

I guess we will see. If it doesn't pan out, the gulf looks to become wide open for future systems shortly after with 70S Tds progged throughout the Gulf, unperturbed, by early/midweek. I will say that something of concern down here is the tendency for GFS and NAM to pretty substantially underforecast surface mixing. Could be offset by minor cloud cover and some greening or really strong moist advection but it could become a problem.

 

Of course at the same time moisture for Sunday has really trended up in the last few runs so we will see 

[brettjrob]

I don't think I've ever seen one of these quick hitting, compact shortwaves pan out in the Plains early in the spring, but that doesn't mean it can't happen. Last night's GFS and Euro both raise an eyebrow for Sunday.

I will say that, as currently progged, I wouldn't be especially worried about mixing as a main failure mode. Rapid cyclogenesis and strong moist advection in the final 12-24 h should minimize the impact there. I think it's more an issue of shortwave timing and whether we can actually pull the preexisting juice to our south up in time.

[bjc0303]

22 minutes ago, brettjrob said:

I don't think I've ever seen one of these quick hitting, compact shortwaves pan out in the Plains early in the spring, but that doesn't mean it can't happen. Last night's GFS and Euro both raise an eyebrow for Sunday.

I will say that, as currently progged, I wouldn't be especially worried about mixing as a main failure mode. Rapid cyclogenesis and strong moist advection in the final 12-24 h should minimize the impact there. I think it's more an issue of shortwave timing and whether we can actually pull the preexisting juice to our south up in time.

Yeah, with the quick progression and development I wouldn't anticipate significant mixing. As it was progged 00/06z, reminded me of May 10 2010 in the loosest way possible (rapid changes, fast compact shortwave) although the shear and instability do not compare.

 

I would have to agree that the next series of waves, pending any significant changes to the forecast output, nothing screams anything significant to me. But the Gulf looks like it'll be good by midweek should things pan out with a particular wave. 70s dewpoints forecast across the gulf, yes please

[Indystorm]

DFW area now looking quite ominous for sig svr for Sunday evening with CAPE and helicity quite favorable per 18z GFS this Tuesday if it continues to hold and the first system gets out of the way.

[Jim Martin]

To what Indystorm is referring to.

[WhiteoutWX]

GFS has taken many steps backward for Sunday as far as moisture quality into Oklahoma is concerned, mainly due to a stronger frontal push with the Friday system. I'm now convinced any tornado threat stays along and south of Red River, with maybe the exception of far SE Oklahoma into SW Arkansas. 

And the broad SW flow aloft it was showing a few days ago for early to middle next week has quickly morphed into one much stronger, slower trough that doesn't look to eject until mid to late next week. Euro may offer slightly more hope, but probably still too far out to speculate what potential that one has though. 

Overall rather disappointing changes for any Oklahoma locals, but hey it's only March. Probably to be expected!

[brettjrob]

The 500 mb pattern progged over the next two weeks right now is nothing short of insane, especially by the standard of recent years. Nonstop intense shortwaves dropping into the Rockies and carving across the central CONUS, one after another, with no end in sight. It's been at least since 2011 since we saw a similar pattern in the springtime, and maybe 2008 for the Plains. Really, the first half of May 2003 is what comes to mind, looking at this morning's GFS. It's just happening 30-45 days too early to take full advantage with these short wavelengths, from a severe perspective. But we'll probably get our first headline-making tornado event of the year (outside the Gulf coast) out of this period somehow, regardless.

[WhiteoutWX]

6 minutes ago, brettjrob said:

The 500 mb pattern progged over the next two weeks right now is nothing short of insane, especially by the standard of recent years. Nonstop intense shortwaves dropping into the Rockies and carving across the central CONUS, one after another, with no end in sight. It's been at least since 2011 since we saw a similar pattern in the springtime, and maybe 2008 for the Plains. Really, the first half of May 2003 is what comes to mind, looking at this morning's GFS. It's just happening 30-45 days too early to take full advantage with these short wavelengths, from a severe perspective. But we'll probably get our first headline-making tornado event of the year (outside the Gulf coast) out of this period somehow, regardless.

It seems like maybe too many short waves for this time of year? Not enough time for moisture recovery? Agreed that you have to think this upcoming pattern has to produce SOMEWHERE...it's just a question of how far north and west the threat can make it.

[bjc0303]

3 hours ago, brettjrob said:

The 500 mb pattern progged over the next two weeks right now is nothing short of insane, especially by the standard of recent years. Nonstop intense shortwaves dropping into the Rockies and carving across the central CONUS, one after another, with no end in sight. It's been at least since 2011 since we saw a similar pattern in the springtime, and maybe 2008 for the Plains. Really, the first half of May 2003 is what comes to mind, looking at this morning's GFS. It's just happening 30-45 days too early to take full advantage with these short wavelengths, from a severe perspective. But we'll probably get our first headline-making tornado event of the year (outside the Gulf coast) out of this period somehow, regardless.

And interestingly the newest GEFS and EPS show more negative height anomalies in the west/desert southwest towards the end of the cycle...so no real end in sight.

 

Courtesy of yet another NPJ extension.

 

Is there any reason this might make for a quiet late April or may? I see people mention this but never based on any logic other than how active it is now.

[bjc0303]

Last night's euro has a decent looking high plains setup Tuesday. Would seem likely to me that supercells initiate on dry line and eventually grow upscale... model QPF seems to support this. 

[brettjrob]

Tuesday is looking more and more like the best shot to start pulling real moisture up more than 2 hours before showtime - something Sunday is sorely lacking on most of today's runs.

[bjc0303]

13 hours ago, brettjrob said:

Tuesday is looking more and more like the best shot to start pulling real moisture up more than 2 hours before showtime - something Sunday is sorely lacking on most of today's runs.

As the GFS trends a little more to the Euro consider me pretty interested in Tuesday. Degree of moisture return will determine how big a day it could be. shear profiles look really nice as a whole on 06z GFS.

ECMWF manages upper 50s/low 60s into the TX PH and west OK. Gonna need to watch that trend. 

 

If anything this general pattern will help bring some *much* needed rain to the area. Low soil moisture and intense mixing is causing severe underperformance as far as moisture goes, and we do not want that problem lingering later into April or May.

[bjc0303]

Well, I have been eyeing Tuesday for a pretty cool minute now and SPC just put out a day 3 enhanced. This one has been trending the right direction for just about everything. Looks to me like a potential tornado event for sure. 

[cheese007]

D1 mod out for today

[andyhb]

Can't say I'm not impressed with the 12z GFS on Tuesday in the PPA-CDS-FDR corridor. Those are some pretty hellacious looking soundings with a very high degree of turning between the surface and 6 km, very low LCL heights (we'll see how moisture behaves) and a pretty classic arcing dryline configuration. Synoptically, especially at 500 mb, there appear to be quite a few similarities to significant early season High Plains events in the past with a large, slow-moving ULL generally near/just east of the Four Corners. Dryline position will probably end up being west of where the GFS depicts it, and there seems to be some concern regarding displacement of the stronger 700 mb flow away from overlapping the effective warm sector.

Oh, and there's definitely some indication of after dark problems, of which this region is no stranger to with early season events.

[Misstertwister]

whats the latest thoughts on what this actual topic is for............Central/Western Medium-Long Range Discussion???

[Chargers09]

 From the SPC long range discussion:

Thereafter, latest guidance suggests that broad and deep surface
   cyclogenesis is possible to the east of the Rockies by the middle of
   next week.  The magnitude of this wave appears supportive of at
   least some risk for considerable severe weather potential that could
   impact portions of the Plains into the Mississippi Valley next
   Tuesday/Wednesday, and portions of the Southeast, and perhaps Mid
   Atlantic, by 12z Friday April 7th.  However, too many uncertainties
   exist, both on the larger and smaller-scale, to allow a forecast of
   15 percent probabilities at this time

[bjc0303]

would be more encouraged if models weren't showing a washout of the gulf 

[bjc0303]

00z ECMWF and last few ensemble runs show quite the pattern this weekend into next week. Think first big chase able setup may come from this one. moisture looks great on deterministic and pattern wise, with a southeast US ridge, the pattern looks great. Given gulf conditions.. a substantial moist layer may develop. Optimism is high.

[WhiteoutWX]

Really confused as to why the SPC outlook for Sunday only extends as far south as Kansas. 12z GFS has some very impressive parameters (minus some S-shaped hodos) all the way south through Oklahoma and into north Texas, with several PDS TOR soundings throughout that corridor. Obviously it's a ways out and could change but given the current data the placement of the risk area seems odd to me. I haven't seen the Euro is it completely different?

[bjc0303]

1 minute ago, WhiteoutWX said:

Really confused as to why the SPC outlook for Sunday only extends as far south as Kansas. 12z GFS has some very impressive parameters (minus some S-shaped hodos) all the way south through Oklahoma and into north Texas, with several PDS TOR soundings throughout that corridor. Obviously it's a ways out and could change but given the current data the placement of the risk area seems odd to me. I haven't seen the Euro is it completely different?

Not really, they are pretty similar last I saw. However, capping looks to be an issue farther south. That's not to say CI won't happen.. The GFS was forecasting CI and so has the ECMWF. Given how far out it is they will likely expand in later outlooks, but better (or should I say more likely to be focused) large-scale ascent will be farther northeast. I'd expect it to expand in subsequent outlooks.

[WhiteoutWX]

1 minute ago, bjc0303 said:

Not really, they are pretty similar last I saw. However, capping looks to be an issue farther south. That's not to say CI won't happen.. The GFS was forecasting CI and so has the ECMWF. Given how far out it is they will likely expand in later outlooks, but better (or should I say more likely to be focused) large-scale ascent will be farther northeast. I'd expect it to expand in subsequent outlooks.

Fair enough, that makes sense. Definitely has my interest piqued. Could be the first big plains setup this year, as you stated previously.

[bjc0303]

1 minute ago, WhiteoutWX said:

Fair enough, that makes sense. Definitely has my interest piqued. Could be the first big plains setup this year, as you stated previously.

GFS showed enough height falls/glancing influence of DCVA from the wave such that CI would be probable along the dry line. Anything less probably results in capping winning out.. You really need large scale ascent to destabilize the atmosphere. Sfc heating is rarely enough.

[bjc0303]

Euro continues to show a pretty nice dry line setup from SW OK into east kansas. CI looks to be an issue far southwest but ECMWF QPF suggests what would probably be discrete supercells along dry line from central OK into eastern KS. 

 

S/SE flow along the dry line currently forecast verbatim, veering to 40 knots S/SW at 850. Definitely one to watch.

 

GFS is in relatively good agreement as well. Fcst soundings show widespread 0-1 SRH ~200 m2/s2, MLCAPE 2000-2500 range. 

[bjc0303]

trend among the most recent 12z EPS 500 height + anomalies mean suggest a nice severe threat Sunday. Prominent east ridging will allow for quality moisture return. Solid EML advection likely as well leading to steepening lapse rates. Looking like a classic dry line setup.