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MattPetrulli

May 15-20 Severe Threat

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Looks like a very active period of severe weather is possible next week with multiple troughs swinging through. Some bigger Plains days are possible with the first one being Tuesday. Only Tuesday is highlighted on day 4-8 but more days are likely to come. 

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Tuesday and Thursday are of greatest interest to me. Thursday pattern and model QPF suggestive of quite the severe event from TX through Nebraska. 

 

12z ECMWF looks to push the Tues/Thurs threats a hair east, involving more of the I-35 corridor/OKC metro.

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3 hours ago, MattPetrulli said:

Looks like a very active period of severe weather is possible next week with multiple troughs swinging through. Some bigger Plains days are possible with the first one being Tuesday. Only Tuesday is highlighted on day 4-8 but more days are likely to come. 

If models continue with what they are showing, fully expect a 30% contour to be added tomorrow across parts of KS/OK for Tuesday, very favorable parameter space coming together.

Current SPC D4-8 regarding the potentially more interesting days, just for posterity: 

 ...Day 5/Tue...

   A strong shortwave impulse will eject across the southern and
   central Plains on Tuesday afternoon. While there are some
   differences in guidance in the evolution of this impulse into
   Tuesday night across the Upper Midwest, agreement remains good that
   a severe threat will develop during the afternoon along a surface
   dryline in the vicinity of western/central KS into western OK and
   perhaps the eastern TX Panhandle and adjacent western north TX. This
   threat may extend further north into parts of the mid-MO valley, but
   capping will be a concern this far north as stronger forcing and
   height falls do not arrive until after 00z. Thermodynamic and
   kinematic parameter space will support supercells with all hazards
   possible across the 15% risk area.

   ...Day 6/Wed...

   Quite a bit of model variability exists on Day 6 with large
   differences in the evolution of the Plains/Upper Midwest shortwave
   trough. Some threat could exist across parts of the upper Great
   Lakes and mid-MS Valley, or, further south across the central and
   southern Plains and even Ozarks, but, predictability is low given
   several hundred miles of difference in the location of the shortwave
   trough at 12z Wed. This will have large implications on surface
   recovery from convection on Tuesday. Additionally, forcing will be
   more subtle with broad swath of southwesterly flow and potential
   shortwave ridging over much of the Plains. While a severe threat
   likely will evolve somewhere in the central U.S, uncertainty is too
   high to introduce any probs at this time. 

   ...Day 7/Thu...

   By Thursday, the larger-scale western upper trough begins to
   progress eastward. However, uncertainty remains quite high given
   continued large differences in latitude of the ejecting upper trough
   and attendant surface cyclone. While a severe threat is possible
   along a surging dryline somewhere from NE to TX, and potentially
   further north and east along whatever warm front develops, details
   are still too uncertain to introduce probabilities at this time. 

   ...Day 8/Fri...

   Model solutions diverge even further by Friday and predictability is
   too low.

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5-day mean pattern from the GFS for next week has been consistently a picture of just persistent favorable conditions, thanks to ideal wavebreaking from the Plains to Midwest.

This is one of those situations where I haven't bothered looking at any individual day yet, and probably won't until morning of. A signal like this in a time-averaged pattern is impressive and something that does not come around every year -- an indication of potential that surely will be realized by at least one or two days.

 

 

GFS_SVRpattern_04_08.thumb.png.8e302bb045c0593edfd40aa5b95661b4.png

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Interesting trends are for a stronger wave farther west/south on Tuesday rather than the whole thing ejecting to the north. As a result, strong vorticity max leads to pressure falls along the OK/SW OK portion of the dry line. This causes backed surface winds (also strengthens/backs 850 winds) enhancing tornado/sig svr potential in SW OK. NEXLABdpdt-00Z-20170517_GFSSGP_500_spd-1

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Local WFOs already beginning to get concerned...

ICT: 

Quote
.LONG TERM...(Tuesday through Friday)
Issued at 247 PM CDT Fri May 12 2017

This period has the potential to be increasingly active
thunderstorm-wise, as a longwave trough sets up over the western
CONUS and ejects a handful of shortwaves northeast across Mid-
America. In the low-levels, persistent southerly flow will allow
rich Gulf moisture to spread north, ahead of a wobbly High Plains
dryline that will at times reload and sharpen during the
afternoon/evening hours. While timing, placement and amplitude of
individual shortwaves are still in question, consensus between
ensembles and deterministic models suggest the highest potential
for thunderstorms will be Tuesday afternoon-night, and Thursday-
Friday night. The overall synoptic setup along with favorable
instability and deep layer shear will likely favor a few rounds of
severe storms, some of which could be higher-end magnitude,
especially if the not-so-meridional mid/upper winds of the GFS and
Canadian models verify compared to the more meridional ECMWF.
Additionally, a few more rounds of heavy rain/flooding are
possible, especially Thursday-Friday night.

OUN: 

Quote
Tuesday is the most concerning day of the next seven, although
there are some uncertainties. Models all show a deepening
shortwave trough over California on Monday ejecting east-northeast
quickly on Tuesday. Deterministic guidance is in reasonably good
agreement with timing but there is some spread in the ensembles.
GEFS mean is slightly faster than deterministic GFS. Although
most of the members are pretty close, a few are quicker.
Regardless, there is reasonable enough agreement to have fairly
high confidence in instability, shear, and ascent being in phase
for severe weather, including the potential for a fairly
significant event with all severe hazards possible. Once we have a
better handle on timing of the wave we will have more confidence
in magnitude of the event and placement of the highest threat
areas (which could be slightly north of the area). Right now, it
appears that thunderstorms would develop on a synoptically-active
(eastward shifting) dryline driven by fairly strong mean semi-
orthogonal flow. This would be most likely over western Oklahoma
and north Texas. Convection would then shift eastward across the
area into the evening/overnight. Coverage may not be particularly
high, especially if the wave takes a track further northwest
and/or is less amplified.

Some convection may linger or redevelop across the southern
portion of the area on Wednesday, although significant mid-level
height rises and subsidence in the wake of the aforementioned
shortwave trough should limit convective potential.

All medium range deterministic and ensemble guidance shows a deep
closed low evolving to our west on Wednesday and approaching the
area late Wednesday. Low level response to this will result in a
northward surge of moisture into the area. Forecast soundings
suggest a fairly deep saturated low levels beneath capping
inversion, and the QPF signal in the models Wednesday night may be
too aggressive (typical in this scenario). We have lowered
precipitation probabilities below the blends accordingly.

Thursday and Friday appear to be quite active as significant
moisture is expected ahead of the slowly eastward moving deep
closed low. Severe thunderstorms will be possible. Anomalous PWAT
values would support a flooding threat as well.

Most other WFOs (GID, DDC, TOP, etc...) are highlighting the favorable pattern for severe storms as well, but ICT and OUN went into more detail.

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Looks like Reed Timmer has zeroed in on these days 

 

http://premiuma.accuweather.com/premium/timmer_promo/

 

Friday, May 12, 2017 20:51
Severe weather possible every day next week across parts of the central and southern U.S.! Here is the initial breakdown:

SUMMARY: Severe weather will be possible over parts of the central and southern U.S. nearly every single day next week, with the most significant and widespread events including tornado potential on Tuesday afternoon across western Oklahoma into eastern Nebraska, and Thursday across roughly a similar area. Below is a day-by-day breakdown of the severe weather each day starting on Monday night. Please realize that this is long-range model guidance, and the severe weather target areas will likely change drastically between now and then.

Monday:

An active week of severe weather will begin late on Monday most likely along or just east of a dry line draped across western Kansas into southwestern Nebraska. However, the environment looks most favorable over southeastern South Dakota, northeastern Nebraska and across northern Iowa, but ridging aloft likely will prevent any storms from developing there. Assuming a supercell or two can develop Monday evening in western Kansas into southwestern Nebraska, a few tornadoes could be possible through a few hours after sunset with an intensifying low-level jet.

 

590x382_05122054_longrange_blog_monday.png

 

 

Tuesday:

By Tuesday afternoon, a much-expanded warm sector will stretch from West Texas to as far north as eastern Dakotas/Minnesota with widely separated supercells, including tornado potential, possible from northwestern Texas through eastern South Dakota. The greatest tornado threat based on the current long-range models appears to be setting up for western/central Oklahoma/Kansas. Meanwhile, an even stronger wave right on the heels of this one is making "landfall" from the northern Pacific Ocean in southwestern Oregon.

 

590x386_05122055_longrange_blog_tuesday.png

 

Wednesday:

Conditions appear conducive for supercells, isolated tornadoes across eastern Iowa, northern Illinois, southern Wisconsin in the northern part of the warm sector ahead of the shearing out lead system. Meanwhile, the next upper-level storm system will head toward the central/southern Great Plains, likely with nocturnal severe convection across the southern High Plains as low-level jet intensifies on Wednesday night.

 

590x390_05122056_longrange_blog_wednesday.png

 

 

Thursday:

The second, stronger of the upper-level storm systems next week will continue to amplify over the Four Corners region by Thursday, with a massive warm sector with strong instability and wind shear from northwestern Texas through central/eastern Nebraska, likely expanding farther north. It looks like this will be the most significant and widespread of the severe weather events next week, and tornadoes will certainly be possible if these models are even close to verifying.

 

 

590x383_05122056_longrange_blog_thursday.png

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20 hours ago, weatherextreme said:

Looks like Reed Timmer has zeroed in on these days 

 

http://premiuma.accuweather.com/premium/timmer_promo/

 

Friday, May 12, 2017 20:51
Severe weather possible every day next week across parts of the central and southern U.S.! Here is the initial breakdown:

SUMMARY: Severe weather will be possible over parts of the central and southern U.S. nearly every single day next week, with the most significant and widespread events including tornado potential on Tuesday afternoon across western Oklahoma into eastern Nebraska, and Thursday across roughly a similar area. Below is a day-by-day breakdown of the severe weather each day starting on Monday night. Please realize that this is long-range model guidance, and the severe weather target areas will likely change drastically between now and then.

Monday:

An active week of severe weather will begin late on Monday most likely along or just east of a dry line draped across western Kansas into southwestern Nebraska. However, the environment looks most favorable over southeastern South Dakota, northeastern Nebraska and across northern Iowa, but ridging aloft likely will prevent any storms from developing there. Assuming a supercell or two can develop Monday evening in western Kansas into southwestern Nebraska, a few tornadoes could be possible through a few hours after sunset with an intensifying low-level jet.

 

590x382_05122054_longrange_blog_monday.png

 

 

Tuesday:

By Tuesday afternoon, a much-expanded warm sector will stretch from West Texas to as far north as eastern Dakotas/Minnesota with widely separated supercells, including tornado potential, possible from northwestern Texas through eastern South Dakota. The greatest tornado threat based on the current long-range models appears to be setting up for western/central Oklahoma/Kansas. Meanwhile, an even stronger wave right on the heels of this one is making "landfall" from the northern Pacific Ocean in southwestern Oregon.

 

590x386_05122055_longrange_blog_tuesday.png

 

Wednesday:

Conditions appear conducive for supercells, isolated tornadoes across eastern Iowa, northern Illinois, southern Wisconsin in the northern part of the warm sector ahead of the shearing out lead system. Meanwhile, the next upper-level storm system will head toward the central/southern Great Plains, likely with nocturnal severe convection across the southern High Plains as low-level jet intensifies on Wednesday night.

 

590x390_05122056_longrange_blog_wednesday.png

 

 

Thursday:

The second, stronger of the upper-level storm systems next week will continue to amplify over the Four Corners region by Thursday, with a massive warm sector with strong instability and wind shear from northwestern Texas through central/eastern Nebraska, likely expanding farther north. It looks like this will be the most significant and widespread of the severe weather events next week, and tornadoes will certainly be possible if these models are even close to verifying.

 

 

590x383_05122056_longrange_blog_thursday.png

Lol are the trying to draw a penis?   In all seriousness, next week looks impressive over a fairly large area.  One or more of the days will produce somewhere.

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12Z NAM showed some issues with Tuesday's setup, but it's probably useless until tomorrow. GFS looked pretty neat. 

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12z Euro was indicating some rather rambunctious low level shear profiles both on Tuesday (00z MPAS agreed here) and Thursday generally over the same area. Especially the latter with a 40-50 kt southerly or even south-southeasterly low level jet across W OK and the E TX Panhandle. It does have some sub-tropical jet induced junk in central TX (need to watch subtle vort maxes along this for effects on the low/mid level mass fields), but still manages sizable CAPE across the primary threat area.

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Agreed with what's already been said, that Tuesday looks pretty nice on the GFS and Euro. Thursday does too if the warm sector can remain undisturbed. Thursday/Friday's setup reminds me of a set up we had in mid-May last year, where we had a really impressive parameter space, but everything went up at Noon and it was a dud. Let's hope that is not the case this go around. 

Perhaps the biggest threat from all of this may be the flooding. Much of S KS, OK, S MO and NW AR have had 10-30 inches of rain in the last 60 days and another 2-4 inches (at least) is expected. 

 

Screen Shot 2017-05-13 at 6.03.45 PM.png

p168i.gif

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I'm a little concerned with how sharp the shortwave is progged to be for Tuesday. The more meridional mid level winds ahead of the trough axis could possibly create some issues with backing winds between 700-500 mb. It's still way near the end of the run, but it appears the NAM has begun to pick up on this potential issue.

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1 hour ago, rockchalk83 said:

Agreed with what's already been said, that Tuesday looks pretty nice on the GFS and Euro. Thursday does too if the warm sector can remain undisturbed. Thursday/Friday's setup reminds me of a set up we had in mid-May last year, where we had a really impressive parameter space, but everything went up at Noon and it was a dud. Let's hope that is not the case this go around. 

Perhaps the biggest threat from all of this may be the flooding. Much of S KS, OK, S MO and NW AR have had 10-30 inches of rain in the last 60 days and another 2-4 inches (at least) is expected. 

 

Screen Shot 2017-05-13 at 6.03.45 PM.png

p168i.gif

Are you referring to 5/26/16? MDT risk day that went to sh*t because of this, along with perhaps some storm mode and storm-scale process issues due to VBV. VBV is such a frustrating thing as the effects of it are still not exactly clear. Almost every day I can think of that became a bust, and VBV got blamed had many other issues such as 1. early CI, 2. LOTS of storms, 3. Weak/modest low-level winds... Tuesday will probably have none of those issues, so if the VBV on the NAM comes to fruition I will be curious how it effects the discrete/isolated storms in an otherwise very favorable environment. 

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I'm not sure, given the current forecast wave timing, that I really see Thursday as an early CI day, at least as early as 5/26/16 was, probably around 4pm or later as it sits right now verbatim in the "main" area for Thursday. Perhaps an issue could be seen with some morning convection further south, as well as the issues discussed above by Andy. Thursday looks more solid imo than any other day, Tuesday would be a fairly high-end threat imo but CINH will likely increase markedly after dark, VBV (if the NAM is correct with depicting fairly significant backing below 500mb) could play a role in deterring discrete storm-modes possibly as well as disrupt some storm-scale processes related to tornadogenesis, and the area with the best parameter-space really isn't forecast to be very wide which could also impact tornado potential as storms are going to have fairly fast motions... and last but not least T/Td spreads (Less than ideal LCLs) could be fairly large as well, but that's still a bit uncertain at this point.  Nonetheless still think we will likely get a few tubes before 02Z on Tuesday. I'm not quite sure what the ceiling is for any of these days, nothing really screams outbreak/big day but the parameter space on a couple of the days will likely be fairly substantial. 

Seems like hype for this is pretty subdued compared to what it would be because of the debacle that late April was. Suppose models also aren't showing a synoptically obvious massive day (along with those insane parameters on the GFS) like Friday (4/28) was once forecast to be. 

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I think Tuesday and Thursday could both play out to be higher-end days...devil is always in the details, and those details won't really become clear until down the road.

Regarding the narrow warm sector for Tuesday... It's pretty interesting that surface temps are so low at OKC/Central OK by 00z. None of the models (except maybe the NAM) forecast substantial cloud cover yet soundings exhibit low 70s surface temps east of the dry line. SREF forecasts a mean sfc T of 78 or so throughout the same area, so I'm not really sure I buy it. The warm sector probably will be pretty narrow as far as favorable thermodynamics go, but not as narrow as shown.

Thursday could be a pretty volatile day.. ECMWF took a huge step forward with a less amplified/less meridional wave, and a substantial low-level jet. Convective timing will be something to watch, but could easily be quite the day. Again - we're five days out, so details will change often (as they still probably will for Tuesday even being three days out).. but I like the look of both days. 

 

To be completely honest veer-back profiles are not really that much of a concern to me except when they clearly prove to be inhibiting low-level SRH or redirect deep-layer shear vectors to be oriented significantly more N/S (boundary-parallel) than they would be otherwise. Also should consider storm coverage when looking at these hodographs. The VB pattern I'm seeing on Tuesday doesn't look like anything that would keep me from chasing.

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00Z NAM continues with its VBV signature below 500mb, and also does not develop any convection along the dryline prior to 00Z, GFS says otherwise. NAM is a bit of an outlier IMO as of now, its still a bit outside of its skill range. 

00z GFS verbatim, without delving too much into convective parameters, develops what would be a potentially high-end day on Tuesday across western OK/KS. At the surface a 990mb low (more like a surface trough due to no westerly or easterly components) develops across NW KS by 7pm with a surface dryline extending roughly from Hill City, KS southward to Dodge City to Magnum, OK and areas south. South-southeasterly SFC winds exist east of the dryline across W/C KS and W/C OK amidst a moist and strongly unstable environment, with 63-68DPs across most of Kansas and Oklahoma and CAPE values of 2000-3000+J/KG along and east of the dryline. Above the surface, a very large 40-45kt low-level jet at 850mb prevails across much of plains, which is helping aid in more-than-sufficient ESRH of 200-300m2/s2... with a substantial, slightly negatively tilted, trough ejecting into the plains by 21-00z, with 50-60kt flow at 500mb across the warm sector by 00z, helping provide 45-60kts of cloud bearing shear. GFS QPF would indicate several dryline supercells developing between 21-00z across western KS and OK... Biggest question if you're looking at the GFS would be **how long** will the higher-end severe threat exist? As CINH increases significantly by 03Z, with questions of the breadth of the warm sector (eastward extent of better instability) still withstanding. ATTM it appears at least a few hours will exist along and east of the dryline in W KS and W OK where all significant-severe hazards could occur, including very large hail and tornadoes - including at least some risk for strong tornadoes with any well-developed supercells... But all of that is just off of the GFS verbatim.

 

Obviously questions are still abound about dryline location as well as moisture-quality and associated T/Td spreads, and that really won't be ironed out until the day-of... As well as how much of a VBV signature will exist and where exactly in the wind profile it will be located. But aside from that it looks pretty good to me. 

Given that it is still 5 days out, wont get into much detail about Thursday... But it continues to look like a potentially big day across KS/OK on the GFS

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Regarding the 00z NAM, what is happening here in Kansas? Is the moist sector advancing northward into the dry sector through the daytime, without significant convergence?

OXcpqoE.png

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43 minutes ago, Chinook said:

Regarding the 00z NAM, what is happening here in Kansas? Is the moist sector advancing northward into the dry sector through the daytime, without significant convergence?

OXcpqoE.png

That would be the intersection of the dry line and the cold/quasi stationary front sagging between the low that ejects overnight Monday and the developing lee cyclone Tuesday afternoon/eve.

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One thing to note is that between 700 and 500mb, there is a very slight backing based on some GFS soundings.  This backing should be weak enough to not break things. One plus with it is that it's a sign of cold air advection (If someone wants I can do the calculation, but I took a final on it Friday and I would rather let the model do the math for me).  This should steepen the lapse rates below this area, increasing instability. This seems like it could be one of the primary reasons the GFS totally erodes the capping inversion.

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Was going to point this out on a post here, but I tweeted it already so I figured I'd just repost it here.

The above leads to (on both the NAM and GFS) a 6-10 mb pressure fall in 6 hours between 18z and 00z associated with the lee cyclone in eastern Colorado. That is going to lead to a pretty impressive low level jet and possibly surface backing. Certainly no slouch of a synoptic scale shortwave for May.

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5 minutes ago, andyhb said:

Was going to point this out on a post here, but I tweeted it already so I figured I'd just repost it here.

The above leads to (on both the NAM and GFS) a 6-10 mb pressure fall in 6 hours between 18z and 00z associated with the lee cyclone in eastern Colorado. That is going to lead to a pretty impressive low level jet and possibly surface backing. Certainly no slouch of a synoptic scale shortwave for May.

Very impressive.

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Good write up from DDC regarding Tuesday and later in the week as well:

Quote
Tuesday will likely be an active severe weather day across much of
the southwestern KS through southwest Texas corridor. Global models
show a surface low deepening down to 990-992mb with enhanced
downslope momentum south of the low and along/west of the dryline.
The dryline by late afternoon should extend along a line from
roughly Hill City to Dodge City to Canadian, TX. Good convergence
along the dryline should support aggressive surface based
convection. 500/250mb flow will increase even more to the tune of
50/75 knots, respectively. The shear profile puts convective mode
well into supercell category and when you add in the low level
moisture factor, the CAPE/Shear combination would support longer
lived supercell storms, potentially capable of high end severe
weather, including tornadoes, from west central KS and points south.

As we head deeper into the work week, the forecast becomes more
difficult regarding severe weather risk. The initial storm system
Tuesday is stronger and farther south than previously expected, and
this will play into the forecast Wednesday-Thursday. On Wednesday,
The Pacific Cold front (acting dryline) will push way east into far
eastern KS/OK as west winds surge dry air into our region. Drier air
will preclude thunderstorm activity Wednesday as west winds prevail.
That said, as the first low lifts out, some wrap-around moisture may
clip the Hays area through the afternoon hours, although this should
be more showery in nature vs. thunderstorms.

Right on the heels of this first storm is a much larger system,
allowing for aggressive cyclogenesis again on the High Plains by
Thursday. This storm, however will be working with dry air across
southwest KS all day Thursday. It will take significant cyclogenesis
and backing of low level winds to bring the moisture back northwest
into southwest KS. For this reason, there is a bit lower confidence
this forecast cycle, as far as how far northwest significant severe
weather will reach into the southwest KS region. The evening hours
Thursday will be very critical, because this is the time frame when
low level moisture can come roaring back northwest as winds back
around to the southeast. The GFS and ECMWF both show lower 60s
dewpoints pulling back as far west as a U283 corridor during the
early evening hours. The cyclogenetic environment with significant
low level wind shear would support tornadic supercell storms
Thursday evening, particularly south of the Arkansas River and east
of U283.

Global models are now showing the large upper low will remain quasi-
stationary through Friday, so that another round of severe weather
could impact western Kansas Friday. These solutions are slower and
farther west than before, putting more of western Kansas in a threat
for severe weather. This entire trough will not push east of
southwest Kansas until sometime late Saturday, now, per the ECMWF.
If this is the case, then even an early afternoon strong/severe
weather threat cannot be ruled out. Also, if the ECMWF is any decent
guidance at all, much of southern and western Kansas should see
quite a bit more rain.

 

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I'm getting ready to roll out for my first multi-day chase trip. I'll be starting off tomorrow in the Texas Panhandle with a working target near Pampa. I'm not expecting a big tornado day or anything like that tomorrow due to large dewpoint depressions/high LCLs and barely sufficient shear, but trends in the NAM and some of the CAMs are encouraging for some (hopefully picturesque) storms in the panhandle. A surface Theta-E axis may end up nosing its way up along the Caprock Escarpment as progged by the NAM, which makes sense considering the geography of the region.

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Seems like with the recent upgrades, the days of the NAM being the severe wx hype machine are no more. Likewise, 18z 3km NAM actually looks decently interesting for Tuesday. Tuesday doesn't look quite as interesting at this point to me as it once did, but still will probably see a couple tornadoes. Thursday continues to look like the highest-impact/most widespread day this coming week. 

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Well, anyone keen on Thursday's severe prospects may hold off for a moment. Quite the assortment of model solutions for Thursday, ranging from something in the E TX PH as the ECMWF shows, to a borderline outbreak scenario (00z GFS), to a non-event with a cold front/pacific front blowing through central OK by 18-21z (12z NAM)... Take your pick 

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17 minutes ago, bjc0303 said:

Well, anyone keen on Thursday's severe prospects may hold off for a moment. Quite the assortment of model solutions for Thursday, ranging from something in the E TX PH as the ECMWF shows, to a borderline outbreak scenario (00z GFS), to a non-event with a cold front/pacific front blowing through central OK by 18-21z (12z NAM)... Take your pick 

Such disagreement for it being >84 hours out. Jesus. NAM shows extreme instability developing across OK and KS, but again, its with a cold front.. SFC low also develops much further north on the NAM, meaning S/SSW surface winds would likely prevail across OK if that were to happen. Ugh. NAM is out in left field on this one imo. 

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The 06z NAM shows what I would think is a loaded gun profile by 18z in C OK, with the wave amplifying over the Rockies similar to the 00z GFS.. The 12z NAM and 06z GFS runs may be outliers given the overall consistency between the GFS/ECMWF.

 

The SREF essentially captures this in its tremendous spread for Thursday. OKC by 00z could see anywhere between 5000 MLCAPE and 38, according to the latest SREF. Dewpoints range from upper 60s/low 70s to 50s. What is pretty certain is there will likely be strong shear in the region. Spread between members on dewpoint for Thurs does suggest to me that perhaps the boundary will remain west of OKC, but there is a lot of spread and it's the end of the SREF range... Hopefully 12z GFS/ECMWF bring some better clarity to Thursday rather than continue to introduce alternative scenarios.

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