Central/Western Medium-Long Range Discussion

[jojo762]

34 minutes ago, Chinook said:

SPC day-3 (Friday) outlook includes northeast Texas and southwest Arkansas. Tonight's 3km NAM shows this impressive sounding near Texarkana, AR. This is some nifty eye-candy. It is In the warm sector, before scattered storms develop in Oklahoma/Arkansas. The only weakness here would be winds that are weaker at 300mb-250mb, compared to 500mb.

Putting aside all over context, this sounding SCREAMS HP supercell with intense mesocyclone. 

[Quincy]

Assuming the model prog is correct, it's just a messy setup with a cold front crashing south from Oklahoma. Soundings ahead of the front show a monster cap near the Red River and into East Texas, although that is less of a problem up into Arkansas near the warm front. In such a scenario, we'd probably see a big squall line with perhaps a few embedded supercellular elements, but definitely HP.

I also don't like the looks of limited CAPE in the lowest 2-3km. So far this year, we've had no problem driving the EML eastward with impressive 700-500mb lapse rates (probably dry air punching farther east with the ongoing High Plains drought and cold intrusions from the north), but a lot of the setups so far have had limited low-level CAPE. I guess that's to be expected until we're later in the season and it's easier to get surface temperatures into the 80s.

 

[bjc0303]

Just took a look into the 00z ECMWF op.. Gotta say if you speed the progression of the euro up by ~6 hour or so.. You're probably looking at a rather robust severe weather event over the plains.

[cheese007]

Day 2 ENH out for ArkLaTex into MS

[jojo762]

Next Friday has a fairly interesting setup on the Euro. Would likely be looking at widespread severe storms, with at least a marginal tornado threat... OR Thursday potentially if the system were to speed up, which would probably end up resulting in a higher tornado threat. 

[Chinook]

Next week: (April 14-15) I wonder if we could get a severe weather outbreak in the central-southern Plains and a blizzard in the northern Plains on the same day. Today's GFS has a low pressure of 972 mb next Friday.

[WhiteoutWX]

Gfs and euro are worlds apart with the timing of the wave ejection end of next week. Gfs says late Thursday, euro says Friday. Severe potential much greater on the Euro with better moisture and shear.

[bdgwx]

That is a huge powerhouse trough and upper level low showing up on the 12Z EPS. By 18Z on Friday (hour 174) it has 3 fully closed 500mb isohypses and that's just an ensemble mean. The 12Z GEFS also shows big troughing during this period. That's a pretty strong signal for a big weather maker. And it's that time of year so...

[bjc0303]

Operational 12z Euro looks like a pretty nice event over OK, KS, and adjacent areas. This in large part to a potent vort max on the southern periphery of the larger central US trough. As a result of the approaching vort max, consolidated pressure falls in OK lead to backed winds along the entirety of the dry line. This configuration with enhanced downward momentum transport on the dry side of the dry line, and enhanced lift, would probably lead to a mesolow/dry line bulge configuration over OK. Combined with strong height falls, the ECMWF initiates convection/QPF in a signal that suggests scattered convection along the dry line from OK into KS, likely supercellular.

 

This run certainly presents its most potent threat yet across the I-35 corridor and areas east, with strong S LLJ and strong SW winds aloft. Perhaps backing aloft, which could prove to be a mitigating factor with time regarding storm mode. All of this is of course perfect progging the 12z ECMWF.

[bjc0303]

Forecast graphics to accompany the above:

 

 

 

 

 

 

 

 

 

[jojo762]

1 hour ago, bjc0303 said:

Forecast graphics to accompany the above:

 

 

 

 

 

 

 

 

 

Not a PERFECT looking setup, but a damn good looking one nonethless. If we can get flow to be just a tad less meridional looking, that'd really increase the threat level markedly imo. Anyways, this is probably the sexiest looking dryline and warm sector we've seen in quite some time. Regardless of what the "king" I said showing, this is still a week out, so probably shouldn't get my hopes up. 

[Radtechwxman]

What site did you get those euro graphics from? I have a subsription to weathermodels now but not impressed

[canderson]

Had large almost tennis ball sized hail at my parents last night just NE of Longview. 

[Chicago Storm]

7 hours ago, StormChaser4Life said:

What site did you get those euro graphics from? I have a subsription to weathermodels now but not impressed

Looks like weatherbell.

[jojo762]

00Z GFS and the 12Z Euro are incredibly far apart in many, many ways for 4/13... geez. The euro would appear to imply a higher-end threat for a large part of the eastern plains with an environment favorable for scattered supercells along the dryline with moderate instability and ample deep-layer and sufficient low-level shear, whereas the GFS has a very fast moving cold front with deep-layer flow mainly parallel to the front. 

Obviously a lot of time to work details out, but to see such a spread in the op models is not great. Even the GEFS members show a similar spread. With some supporting more of euro solution, and most supporting more of a easterly/fast solution. 

[CheeselandSkies]

How the heck does the 12Z GFS wipe the Gulf bone dry next Monday (week from tomorrow) and then have upper 60s to the Red River by Wednesday evening?

[bjc0303]

Boy the 12z euro pretty much annilhates the gulf. Meanwhile the EPS shows several western troughs passing through afterward. Man am I tired of these garbage April years. Used to be you could actually get tornadoes in April

[Quincy]

This Thursday/Friday storm system is kind of funny. Instead of being upset or depressed with the following scenario, I actually take a moment to chuckle and move on. It's not worth it getting upset over a lousy pattern.

Assuming the latest models are close to right, both the GFS and Euro take a <982mb low from west to east across Nebraska Thursday evening into the overnight. Despite such a strong surface cyclone so far north, the Euro struggles to bring 60F dew-points to the Kansas border by 00z Friday, while the GFS does manage to bring dews into the lower 60s as far north as Kansas City. 

All else put aside, if someone said that a deepening 982mb low was going to move across Nebraska in mid-April, the alarm bells would probably be going off for a potential severe weather event. Since temperatures aloft are going to be quite warm and low-level moisture will be lower-end for the setup, it's probable, if not likely, that no convection will initiate in the Plains on Thursday. Sure, the event is still several days out and if the low-levels improve a bit, there's still a shot at something conditional, but it looks like Thursday will probably be wasted. If that wasn't bad enough, Friday has better potential, but the warm sector will be relatively narrow, the best forcing becomes farther displaced from areas with more favorable buoyancy and most, if not all of the convection should initiate over "poor" terrain in the Arkansas/Missouri vicinity. 

Too slow for Thursday to be promising and probably too sloppy of a setup for a bigger event on Friday. It's also slowed down and shifted enough west that the corn belt region will likely be on the cooler side of the setup, rendering any severe threat close to zero there.

The weekend looks like another trough over the eastern third of the U.S., but there are signs that the pattern gradually becomes more conducive for severe weather in the central states by the following week. That's not saying a lot given the calendar, but as it stands, it still looks like nothing major in the foreseeable future.

We had snow yesterday and now the models show temperatures in the 90s to around 100F for parts of western Oklahoma on Thursday.  

[andyhb]

2010s post-2012 are fun, eh?

This entire regime that we've been in for most of the last half decade has been very testing on my patience for following this stuff (and that says a lot). Fortunately there was 2016 to have success with chasing to keep the interest high, but aside from that, not a whole lot.

All of this bupkis on Twitter/etc. about calling the season now isn't helping either.

[cheese007]

Hey at least 2017 met the average tornado count wise

[CheeselandSkies]

6 hours ago, andyhb said:

2010s post-2012 are fun, eh?

This entire regime that we've been in for most of the last half decade has been very testing on my patience for following this stuff (and that says a lot). Fortunately there was 2016 to have success with chasing to keep the interest high, but aside from that, not a whole lot.

All of this bupkis on Twitter/etc. about calling the season now isn't helping either.

I recall 2012 being the worst severe season of the lot. The "season" was essentially March 2nd and April 14th. I remember being totally stoked for all that March and early April heat this far north to lead to some epic severe weather outbreaks (think mid-March 1990) when those powerhouse early season systems plowed into an airmass that they didn't have to modify from Arctic conditions at the 11th hour, but aside from those two days (one well southeast and one well west of here), such systems never came. It hardly even stormed around here, and then we baked. Wisconsin recorded a measly four tornadoes for the entire year, and Illinois was well below average as well.

I'm still convinced April 2011 broke something in the atmosphere's ability to produce a proper tornado season. Even the ensuing May was weird, dead for the first three weeks followed by three more days of extreme violence, then quiet again.

2013 had the back half of May and the fall outbreak in IL/IN and that's about it.

2014, until now as bad as I thought it could get in terms of a winter hangover, had April 27-28 and June 16-18, not much of note apart from that. The few setups in May were tempered by lingering cold air.

2015 had a certain event three years ago to the day that I still can't think about too carefully without wanting to put a gun to my head. Early-mid May were fairly active, but what looked like it would be the biggest day (May 16th) couldn't hit its ceiling due to lingering junk convection and cool outflow over all but a small portion of what would have been a Plains-wide risk area. There was one regional opportunity in late June which I chased and was looking right at where a tornado was, but it was rain-wrapped UNlike that certain April event. Then it had the anomalous December outbreaks related to the Super Nino.

2016 had the active February in Dixie and the East. Mid-March had one opportunity in the upper Midwest region, when I got my only glimpse of an actual tornado, but it was just that, a glimpse in the lightning flashes of a large cone funnel hanging down to the tree line after dark. May produced three potential career highlight chase days on the 9th and 24-25 but with little activity otherwise. My vacation started on the 30th. Ouch, and June turned out to be one of the quietest on record until the 22nd, the same day as the previous year when another opportunity presented itself in the same area of north-central Illinois. I got on a tornadic supercell but once again any tornadoes were buried in murk.

Last year was pure garbage in terms of quality chase days, except for that one in FREAKIN' FEBRUARY! I couldn't chase because of a prior commitment, which I made because it was FREAKIN' FEBRUARY and the northern target didn't really look like anything until the day of.

[jojo762]

Friday looks maybe decent on the 00Z Euro, personally I'd stay in eastern/southeastern KS if I was chasing and hope for a supercell that wasn't in the jungle, like they will be in Arkansas. Likewise, storm-mode has me a bit concerned about the northern area due to a less than ideal mid-upper wind profile... Meanwhile, Thursday is an infuriating waste of an IMPECCABLE low-level wind field.  *sigh*

[Drz1111]

seems like both the Euro and GFS are seeing some troughiness out west at day 10?  I can buy it - there's strong support for low heights in the Maritimes and with the wavelengths this time of year that's not inconsistent with something coming out of the four corners. We shall see.

[WhiteoutWX]

23 minutes ago, Drz1111 said:

seems like both the Euro and GFS are seeing some troughiness out west at day 10?  I can buy it - there's strong support for low heights in the Maritimes and with the wavelengths this time of year that's not inconsistent with something coming out of the four corners. We shall see.

Problem is the front late this week plows south basically to the equator...will moisture recover quick enough for whatever next system may approach?

[jojo762]

6 minutes ago, WhiteoutWX said:

Problem is the front late this week plows south basically to the equator...will moisture recover quick enough for whatever next system may approach?

GFS, which is currently a bit faster with that D10+ system says NO with the GOM still largely scoured of moisture. Euro, which is slower with the system looks MUCH better in the Gulf. But another concern could be the system that is right before the one in question.

[Chinook]

If you check the soundings for Thursday, you'll realize that this is going to be a waste of a favorable 0-1km SRH and 0-3km SRH for Oklahoma City, considering there's some CAPE and a dryline/cold front. There's a cap that's fairly strong, so Thursday is probably going to be dry. Friday may be worthy of a slight or enhanced risk for Louisiana, Arkansas, Missouri, and northeast Texas. Possible slight risk scenario for Saturday, east of the Mississippi River.

[Drz1111]

I don't have access to good Euro data, but eyeballing it based on public stuff it looks like there's a pretty big difference between the Euro and the GFS in terms of whether Friday is a viable chase day.

[jojo762]

1 hour ago, Drz1111 said:

I don't have access to good Euro data, but eyeballing it based on public stuff it looks like there's a pretty big difference between the Euro and the GFS in terms of whether Friday is a viable chase day.

12Z Euro setup shows what would probably result in a widespread severe outbreak from SE Nebraska southward into NE Texas with all modes of severe weather possible including some possibly significant instances of hail, damaging winds, and tornadoes. GFS is pretty gun shy, and the NAM looks much more like the euro, but the NAM shows the main tornado threat (and a possibly significant one at that, depending on storm mode) being relegated to SE OK/W AR.

[Chreeyiss]

53 minutes ago, jojo762 said:

12Z Euro setup shows what would probably result in a widespread severe outbreak from SE Nebraska southward into NE Texas with all modes of severe weather possible including some possibly significant instances of hail, damaging winds, and tornadoes. GFS is pretty gun shy, and the NAM looks much more like the euro, but the NAM shows the main tornado threat (and a possibly significant one at that, depending on storm mode) being relegated to SE OK/W AR.

18z NAM appears a little faster and not quite as deep with the trough as the 12z. According to the FWD AFD this afternoon, the 12z Euro has sped up a little bit too, relative to previous runs. Euro still shows pretty substantial storms back into N/NE Texas though. The level of severity on Friday is going to have a lot to do with just how fast that dryline mixes east, and how much the trough will dig and hang back out west. It would seem that the faster this system plows through, the less favorable the shear profiles are overall, and the less instability for storms to capitalize on.  

[jojo762]

21 minutes ago, Chreeyiss said:

18z NAM appears a little faster and not quite as deep with the trough as the 12z. According to the FWD AFD this afternoon, the 12z Euro has sped up a little bit too, relative to previous runs. Euro still shows pretty substantial storms back into N/NE Texas though. The level of severity on Friday is going to have a lot to do with just how fast that dryline mixes east, and how much the trough will dig and hang back out west. It would seem that the faster this system plows through, the less favorable the shear profiles are overall, and the less instability for storms to capitalize on.  

18z NAM was incrementally faster than 12Z but verbatim it actually expanded the area of best parameters. The speed of the system, eastward movement of the dryline, in addition to the effects (and/or actual existence) of morning convection will all play a significant role in how Friday plays out. Euro/NAM both indicate a fairly active day across a large portion of the country. 

STP obviously does not present the whole picture, but gotta admit I was fairly impressed by this. Likewise, the tornado threat is probably limited by mid/upper level flow that is oriented nearly parallel to the dryline... However, if the system ends up just incrementally slower, we could be talking about more favorable wind profiles.