bjc0303

Feeling pretty confident we are going to see a few severe events evolve over the next several weeks, starting somewhere around mid/late next week. Certainly next week could get interesting.

Timing looks okay, but timing and any early shower/elevated convection concerns aren't even worth addressing right now.

Wish I could post latest ECMWF ensemble run. Shows mean west troughing evolving around 22nd or so. We will see.

Pretty small cells, not sure I'd expect an outflow boundary from them unless they congealed into a big mess. And if that were the case, there wouldn't be much time for the cool side to modify.

Indeed; I would agree. Accounts for MJO and other influences as he mentioned. I recall seeing forecasts of GWO entering the phase 1/2 space about 14 days or more before the big outbreak Feb 28, of course there are gonna be pitfalls since severe weather events depend heavily on mesoscale factors that this method cannot account for (large MCS wiping out a warm sector, for example)... But it at least gives clues into the large scale pattern/base state for severe weather. Even now, if you look at the deterministic GFS, there are hints that an extension of the NP jet will make its way to the west coast, and the ridge breaking down in response. Also, Gensini and others produce 2 and 3 week outlooks/forecasts for enhanced tornado activity (link: http://weather.cod.edu/~vgensini/ertaf/) Not sure what they look at in total when making their forecasts, but they agree: "Dynamic models show large amounts of noise for the week 3 period. The current thinking is that a more coherent signal may emerge by week 3 that features a NPJ extension that will need to be monitored. When/if this process occurs, it should lead to a favorable pattern for severe convective storms. This could happen as early as the end of week 3, but likely beyond. Many seasonal climate signals continue to point toward an active base state for severe convective storms. " Next week looks pretty dormant severe weather wise with a western ridge in place, but that looks like it will break down around the 21st or so. Obviously the operational models are inherently super inaccurate this far out but the GFS continues to advertise the breakdown of the ridge and even shows the extension of the mentioned jet into the west coast. We will see. Ensembles have yet to totally show any significant changes/signals for western US troughing.

https://ams.confex.com/ams/28SLS/webprogram/meeting.html#Friday1 Look for "tornado frequency in the US related to the Global Wind Oscillation" and watch Gensini's recorded presentation for more information.

Looks like for the most part the next 10-14 days are going to be pretty darn quiet over the southern and central plains, given large scale ridging over west/central states. A return to a more favorable pattern for severe weather seems more likely after that, with some signal of a pattern change. AAM will remain low, but will build up magnitude into the 1 and 2 phase spaces, associated with enhanced potential for tornado days. Ensembles do not show a strong signal yeto, although operational models do show breakdown of the ridging, even though it means nearly nothing at its current range. GEFS forecast of AAM:

Yeah, GFS has trended some better on instability into east OK with 1000 mlcape. Still considerable spread among SREF members, as well as deterministic guidance. Looking past Monday, still looks like potential uptick in severe next weekend/early next week.

Looking past Monday, GEFS continues to suggest increased severe potential late next week... somewhere around Sat or Sunday

Agreed. Storm mode will also probably preclude sig tor potential, unless open warm sector development is to occur. Not sure this will be the case.

Looks like more than a localized wind/hail threat. Assuming initiation does happen and that the NAM isn't grossly overdoing moisture... Looks like a nocturnal tornado threat into east OK Monday eve/night.

Saw that too. ECMWF is harsher. It basically pushes a high amplitude Ridge over the west/central states. I haven't looked into the ECMWF ensemble, but the GFS ensemble shows support for a multi day severe weather threat next week. interestingly enough the GFS started showing this about when the euro stopped doing so. Looks more like Thursday and/or Friday but I could be mistaken. Edit: 18z GEFS continues to suggest increased severe potential late this upcoming week (most likely Fri-Sat-Sun).

Too early to tell. The operational 12z GFS looks awful... but I am more interested in the ensemble forecast, the 12z operational ECMWF, and SREF forecasts. latest SREF doesn't look awful across OK/SE KS

Although currently an outlier the NAM looks pretty potent for Monday evening across OK and central KS

Hard to tell. I'm not sold yet that moisture return will be sufficient, but it could be. The gulf of mexico made it through the brunt of the cold season without any harsh intrusions. In fact it was one of the warmest seasons for the gulf ever I think... I saw an article about the GOMEX temperatures not dropping below a certain value thru winter since some time in the 60s or something...anyway... The NAM and GFS show quite the deep upper level low approaching the west coast by hour 84. The trend with the GFS has been to deepen and amplify the system with each run. the ECMWF 12z deterministic and ensembles did the same, though to a lesser degree. Personally, there probably will be, somewhere, a marginal supercell environment somewhere, probably farther north where colder Temps aloft will reside over modest moisture. If moisture return is sufficient, which would require stronger return flow/longer or weaker frontal passage than currently depicted, then I could see a pretty widespread severe risk over a large portion of the plains. Finally the GFS for now indicates potential for widespread cloud cover, which would probably kill any potential even with stronger return flow. Next few days will provide more clarity. The shear and dynamics of the system do look impressive. It would help if the system continued its trend to be more amplified with each run.

On the other hand if we get forecast sfc lows closer to 1000 mb the flow will be largely veered and the warm sector will be more in line with what is currently depicted in the day 4-8 outlook.

Key point here is with the jet stream overhead small fluctuations in amplitude, strength, etc make a huge difference, hence varying strength and positioning of key features. Likewise bulk shear will be high given strong flow aloft. if stronger sfc low becomes forecast or evident... could be in for a show given MLCAPE 1000-2000 likely

Not sure it is ever that extreme. I would bet on a dry line no father east than I 35 unless flow becomes veered overall like previous model runs suggested

Idk if it's completely dead in the water. 00z ECMWF pulled the dry line back closer to i-35 again. So did the GFS. here is dprog/dt for GFS.

Yeah, it's nothing really to worry about. Might get some western US troughing as we approach spring break, which would be absolutely perfect. euro ensemble indicates retrogressuon of the west us ridging around the middle of march. For March though you need a few days worth of return flow. ..so we will see how that pans out when the pattern inevitably changes.

Best way to describe evolution of GFS runs would probably be...wacky. Highly inconsistent and lots of spread among ensemble members. Interested in whether the euro continues its consistency.

00z and 12z Euro advect 60s dewpoints into central/eastern OK ahead of an eastward mixing dry line. winds back to S/SE towards 00z. I'm not even going to address the GFS because it is so 1) inconsistent and 2) crappy, so it's a very low confidence forecast (hence predictability too low). However, playing around with a GFS sounding on sharpPy to incorporate what I would anticipate given the ECMWF thermodynamic and kinematic progged profiles, almost verbatim, would yield 1000-1500 MLCAPE, maybe higher, juxtaposed with strong deep layer shear, strong low level shear, etc... with initiation likely occurring just to the west of I-35. Plenty could and probably will change, but the Euro suggests a pretty intriguing event. I definitely have my eyes on it. Unlike past few systems this one looks to have substantial moisture return aided by an ejecting wave/speed max ahead of the main system that, while producing some overnight convection, doesn't obliterate or mess up the warm sector and helps accelerate low level flow in anticipation of the main wave. Probably too much in terms of details this far out, but I think there will be a severe weather event next week. Moisture return and timing of upper level/associated low level response will be key.

Seems like with recent rains, and more importantly, the early greening on the large scale, and GOMEX conditions, that the potential will exist for a somewhat earlier start to the severe weather season, or at least a brief period early next week where active weather takes place. Current GFS forecasts low 60s dewpoints to reach southern/central OK by next Monday. Some ensemble members become more unstable. The Euro is a little less progressive than the GFS and has low-mid 60s dewpoints in OK by Tuesday. Both depict similar setups, with a NE-SW oriented dry line owing to an SW-NE oriented jet streak aloft/SW flow aloft, but shear profiles look impressive nonetheless. Deterministic Euro is currently significantly more unstable than the deterministic GFS. Interesting to see how things unfold... Even a mix of the two models would yield bulk shear ranging in the 50s-60s, 0-1 km SRH 200+, and SBCAPE 1000-1500 j/kg.

Disappointing to see such a potent system will likely pass through with no favorable moisture. Given a respectable return flow scenario, this is a possible tornado outbreak from OK into KS. GFS and ECMWF trend drier, but trend upward with shear. Oh well.

If the system can slow ~24 hours, maybe. The dynamics of the system look really impressive on both 06z deterministic GFS and 00z Euro. Large area of backed surface winds in the warm sector, along the dry line, etc. Transport of EML supporting steep lapse rates. Everything will be in place - except perhaps moisture. Gonna be interesting to watch. Don't get strong dynamics like that in S plains too often per year.