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> March 23-24 Plains Severe Weather, SPC Risk Level; Days 4-8 Possible: Forecasts and OBS
RobB
post Mar 17 2017, 03:50 PM
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QUOTE(StL weatherjunkie @ Mar 17 2017, 04:42 PM) *
There are multiple sites that provide Euro data for free (I haven't had a subscription for years), but for some reason multiple sites aren't plotting the 12z Euro run indicating some data feed problems.

However, comparing the 00z euro with the 12z gfs indicates the greatest differences are not directly related to this storm; rather they appear to be due to major differences in the storm system upstream across the eastern Pacific Ocean. Euro tries to keep them together whereas they are clearly separate on the GFS. I'm solidly in the GFS camp.



EDIT: Also note differences in intensity/position of the trough near Maine. Euro is stronger implying a more robust cold front passage ahead of this system.



You are correct...

QUOTE
WeatherBELL‏Verified account @weatherbell 43m43 minutes ago

Note, the ECMWF 12z products are delayed now for 2-hours+ due to issues with EC supercomputer. Hopefully soon data will flow!
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StormChaser4Life
post Mar 17 2017, 06:27 PM
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Thanks for the info man. Appreciate it! That cold push in the northeast does look pretty strong so in that regard euro may be more accurate. What makes you favor GFS STLweatherjunkie? Funny cuz usually GFS underestimates moisture but it appears it switched with what Euro was showing before
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StL weatherjunki...
post Mar 17 2017, 08:45 PM
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QUOTE(StormChaser4Life @ Mar 17 2017, 07:27 PM) *
Thanks for the info man. Appreciate it! That cold push in the northeast does look pretty strong so in that regard euro may be more accurate. What makes you favor GFS STLweatherjunkie? Funny cuz usually GFS underestimates moisture but it appears it switched with what Euro was showing before

No problem, it's been an active severe thunderstorm season thus far and I have no reason to believe that the active pattern will stop.

Also, looking at the 12z euro and gfs, both solutions indicate severe potential during this time frame.

This post has been edited by StL weatherjunkie: Mar 17 2017, 08:45 PM


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StormChaser4Life
post Mar 17 2017, 09:18 PM
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QUOTE(StL weatherjunkie @ Mar 17 2017, 08:45 PM) *
No problem, it's been an active severe thunderstorm season thus far and I have no reason to believe that the active pattern will stop.

Also, looking at the 12z euro and gfs, both solutions indicate severe potential during this time frame.

Agreed. But obviously if GFS is right the tornado threat will be significantly higher with greater moisture and cape. And a more pronounced upper level system
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ClicheVortex2014
post Mar 18 2017, 12:49 AM
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GFS moved the threat further northwest by quite a bit. Maybe slightly caving into Euro in that regard?



Can't retrieve any soundings from Pivotalweather right now... sad.gif


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StL weatherjunki...
post Mar 18 2017, 01:07 AM
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QUOTE(StormChaser4Life @ Mar 17 2017, 10:18 PM) *
Agreed. But obviously if GFS is right the tornado threat will be significantly higher with greater moisture and cape. And a more pronounced upper level system

CAPE, dew points, and upper level structure are all inter-related details and are similar to snowfall maps. Models will be moving around and agreeing/disagreeing such that a clear signal won't emerge until day 3-5. Even at day 3 the highest threat areas will likely move around.

I really prefer to base my long range forecasts on physical observations and imho Gulf of Mexico sea surface temperature anomalies are the best indicator for low level moisture return. The current GoM SSTAs present a very clear signal that it would be wise to expect solutions suggesting greater moisture return.
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All model guidance is just that, guidance. It is the responsibility of the forecaster to take that information, make it better, and to appropriately communicate the forecast to the users.

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so_whats_happeni...
post Mar 18 2017, 01:39 AM
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Dates are from the 23rd to the 24th. The event for overnight 23rd should be from NE Colorado into western Nebraska maybe as far north as southern south Dakota. May get isolated tornadoes with that as well as a nice hail threat. Maybe some going supercell in structure that could help enhance the region as the surface low ejects into southern Wyoming and what looks like a lee trough tries to form, later on becomes a dry front signature for OK on south which could be rather interesting.

Best forcing goes through those regions into early the 24th may have some warm front forced storms across SE nebraska, NW Missouri, and sw Iowa for 23rd into the 24th as well.

The 24th we see some real action take place as what looks to be a La Junta, CO low ejects out into Northern Texas as a developing dry line holds in western central Texas. The northern half of Texas and western to central OK are in line for some pretty hefty storms as a S/W ejects out from the 4 corners. Overnight event as we get into eastern OK, Eastern Texas, and Arkansas, maybe even up to southern Missouri.

Going to be a real interesting day on the 24th!

GFS shows a band of something trying to form across much of Missouri but have this feeling it may be frontogenetically forced rains and maybe some convection but nothing I can see too severe.

The 25th looks to feature maybe eastern IL, IN, and western OH but looks as though it may turn into more of a wind event as we move in time would not be surprised to see a spin up or two the closer you reside to the SLP. Have to watch and see how that evolves from the 24th situation.


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ClicheVortex2014
post Mar 18 2017, 01:48 AM
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Major problem in the 00z GFS is the extremely dry/capped soundings in the areas with the greatest EHI.

Along the OK/KS border


Along the NE/SD border


This post has been edited by ClicheVortex2014: Mar 18 2017, 01:48 AM


--------------------
Meteorology undergrad at Ohio University

Historic weather events in the Ohio Valley:
- The 1974 Super Outbreak (read more)
- The 2012 "Super" Derecho
- The Great Blizzard of 1978
- ILN Severe Weather Climatology

2017 Weather for Cincinnati

Days >90: 0 (Last: 9/8/16)
Marginal risks: 3 (Last: 3/20/17)
Slight risks: 0 (Last: 9/10/16)
Enhanced risks: 3 (Last: 3/1/17)
Moderate risks: 0 (Last: 6/22/16)
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ClicheVortex2014
post Mar 18 2017, 01:53 AM
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Seems like Euro traded places with last night's 00z GFS. Has about 30-35 dew point difference along the dryline. Widespread 1000-2000 CAPE from Oklahoma up to Topeka. 2000-3000 CAPE down in Texas.


--------------------
Meteorology undergrad at Ohio University

Historic weather events in the Ohio Valley:
- The 1974 Super Outbreak (read more)
- The 2012 "Super" Derecho
- The Great Blizzard of 1978
- ILN Severe Weather Climatology

2017 Weather for Cincinnati

Days >90: 0 (Last: 9/8/16)
Marginal risks: 3 (Last: 3/20/17)
Slight risks: 0 (Last: 9/10/16)
Enhanced risks: 3 (Last: 3/1/17)
Moderate risks: 0 (Last: 6/22/16)
High risks: 0 (Last: 11/17/13)

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so_whats_happeni...
post Mar 18 2017, 02:47 AM
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QUOTE(ClicheVortex2014 @ Mar 18 2017, 02:48 AM) *
Major problem in the 00z GFS is the extremely dry/capped soundings in the areas with the greatest EHI.

Along the OK/KS border


Along the NE/SD border


GFS just 12 hours earlier showed a completely different solution lol/ Showed one consolidated system that traverses the mid section where 00z tonight shows 2 pieces of energy that make for two event regions. lol So I wouldnt hold much stock on a single solution yet bet the 00z did peak my interest in a bit have seen a scenario like that quite a few times so that may not be all to improbable.


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so_whats_happeni...
post Mar 18 2017, 02:54 AM
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I am just drooling over those GOES-16 images from earlier. The detail is absolutely amazing can not wait to have it in full use!
http://climate.cod.edu/data/goes16/meso/

Thanks again JD!


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WeatherMonger
post Mar 18 2017, 07:20 AM
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SPC delineated an area for the 24th

Attached Image


QUOTE
Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0327 AM CDT Sat Mar 18 2017

Valid 211200Z - 261200Z

...DISCUSSION...
...Day 4 to Day 6...
The medium-range models begin the day 4 to 8 period with an
upper-level ridge from the southern Plains extending north
northwestward into the central High Plains and northern Rockies. The
upper-level ridge is forecast to move into the Great Plains from
Tuesday/Day 4 into Wednesday/Day 5 as an upper-level trough
approaches the Desert Southwest. Thunderstorm development with a
marginal severe threat will be possible in parts of the Desert
Southwest on Wednesday as the exit region of a mid-level jet moves
across the region. On Thursday/Day 6, substantial differences occur
in the ECMWF and GFS solutions but both models move an upper-level
trough into the Four Corners region as moisture advection takes
place across the High Plains beneath southwest mid-level flow. Based
on this pattern, an isolated severe threat could develop in parts of
the southern and central High Plains late Thursday afternoon.

...Day 7 and Day 8...
In spite of substantial differences during the mid-week time frame,
the ECMWF and GFS models become in better agreement for Friday/Day
7. Both models move an upper-level trough into the southern and
central Plains during the day and develop an axis of instability
across the eastern parts of the southern Plains. Over the last
couple of days from run to run, the GFS for Friday has been
consistently slowing the upper-level system down. In contrast, the
ECMWF has been consistent with the upper-level trough over the
southern and central Plains for Friday. This adds confidence for the
ECMWF solution especially since the GFS is now in better agreement
with the ECMWF. Due to the amplified nature of the upper-level
trough accompanied with moisture return into parts of the southern
Plains, a severe threat seems possible across parts of the region
Friday afternoon. The greatest potential would appear to be ahead of
the upper-level trough along the moist corridor from northeast Texas
into eastern Oklahoma where a 15 percent contour has been added.

For Saturday/Day 8, the ECMWF and GFS solutions have become in
agreement and move an upper-level trough across the lower to mid
Mississippi Valley. Both solutions also have an axis of instability
ahead of the upper-level trough in the Gulf Coast States. Although a
severe threat will be possible in the Gulf Coast States, too much
uncertainty is present to add a severe threat area.

..Broyles.. 03/18/2017
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RobB
post Mar 18 2017, 07:53 AM
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QUOTE(so_whats_happening @ Mar 18 2017, 03:54 AM) *
I am just drooling over those GOES-16 images from earlier. The detail is absolutely amazing can not wait to have it in full use!
http://climate.cod.edu/data/goes16/meso/

Thanks again JD!



I couldn't agree more! "Wow" does not seem a strong enough word..
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StL weatherjunki...
post Mar 18 2017, 11:58 AM
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Updated CIPS analogs using 00z GEFS output, top image is any severe report bottom image is tornado probability.
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All model guidance is just that, guidance. It is the responsibility of the forecaster to take that information, make it better, and to appropriately communicate the forecast to the users.

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StL weatherjunki...
post Mar 18 2017, 12:05 PM
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QUOTE(StL weatherjunkie @ Mar 17 2017, 09:45 PM) *
No problem, it's been an active severe thunderstorm season thus far and I have no reason to believe that the active pattern will stop.

Also, looking at the 12z euro and gfs, both solutions indicate severe potential during this time frame.

Case and point:
CIPS severe probabilities for days 9-11 and 11-13 indicating the same areas will experience repeated severe thunderstorm/tornado threats for at least the next 2 weeks.
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All model guidance is just that, guidance. It is the responsibility of the forecaster to take that information, make it better, and to appropriately communicate the forecast to the users.

Fervent supporter of the idea to make GFS output beyond hour 168 proprietary! Anyone wanting to post/share/tweet/etc GFS output beyond day 7 should have 1) a limited set of graphics available with the option to 2) contribute a nominal fee to get a full suite of products while improving future GFS output. #EURObusinessfor-the-win
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StormChaser4Life
post Mar 18 2017, 01:25 PM
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Yea I'm stoked for this upcoming pattern. Loaded southwest flow. Hopefully moisture will continue to increase in the coming weeks. Getting into that time of year where moisture should be abundant and move in rapidly. I feel like the system after this one will have better potential from a moisture/instability standpoint. For this system Thurs looks to have the best wind profile but moisture will be iffy. Fri has better moisture but wind profiles could veer more leading to a less discrete storm mode
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StL weatherjunki...
post Mar 18 2017, 05:35 PM
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QUOTE(StormChaser4Life @ Mar 18 2017, 02:25 PM) *
Yea I'm stoked for this upcoming pattern. Loaded southwest flow. Hopefully moisture will continue to increase in the coming weeks. Getting into that time of year where moisture should be abundant and move in rapidly. I feel like the system after this one will have better potential from a moisture/instability standpoint. For this system Thurs looks to have the best wind profile but moisture will be iffy. Fri has better moisture but wind profiles could veer more leading to a less discrete storm mode

No doubt about it, more time for the moisture to pool across the southern plains given no major cold front passages.

My best guess for severe storm mode is there will be some supercells and some bowing segments, which will be located someplace tongue.gif


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All model guidance is just that, guidance. It is the responsibility of the forecaster to take that information, make it better, and to appropriately communicate the forecast to the users.

Fervent supporter of the idea to make GFS output beyond hour 168 proprietary! Anyone wanting to post/share/tweet/etc GFS output beyond day 7 should have 1) a limited set of graphics available with the option to 2) contribute a nominal fee to get a full suite of products while improving future GFS output. #EURObusinessfor-the-win
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StormChaser4Life
post Mar 18 2017, 08:26 PM
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QUOTE(StL weatherjunkie @ Mar 18 2017, 05:35 PM) *
No doubt about it, more time for the moisture to pool across the southern plains given no major cold front passages.

My best guess for severe storm mode is there will be some supercells and some bowing segments, which will be located someplace tongue.gif

Lol. Best forecast ever. But I truly believe we have a potent season ahead. Several active periods. Unlike the last few years where we had a few active periods with a lot of nothing in between. With abundant moisture and a powerful active jet there will def be trouble ahead. I got that 2011 vibe. Obviously likely not to reach the extremity of that but def a year to stand out since then
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StL weatherjunki...
post Mar 18 2017, 09:03 PM
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QUOTE(StormChaser4Life @ Mar 18 2017, 09:26 PM) *
Lol. Best forecast ever. But I truly believe we have a potent season ahead. Several active periods. Unlike the last few years where we had a few active periods with a lot of nothing in between. With abundant moisture and a powerful active jet there will def be trouble ahead. I got that 2011 vibe. Obviously likely not to reach the extremity of that but def a year to stand out since then

2008 and 2011 were the most recent seasons during the cool side of a transition from El Nino to La Nina and their tornado totals are the largest seasonal totals since 2005. 2008 was a lot of smaller outbreaks whereas 2011 was a couple historic/memorable outbreaks and April 2011 was absolutely insane.

Attached Image


When adjusted for inflation this season is on pace to roughly tie the maximum percentile based on data from 2005 (basically tying 2011).

Attached Image


This post has been edited by StL weatherjunkie: Mar 18 2017, 09:07 PM


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All model guidance is just that, guidance. It is the responsibility of the forecaster to take that information, make it better, and to appropriately communicate the forecast to the users.

Fervent supporter of the idea to make GFS output beyond hour 168 proprietary! Anyone wanting to post/share/tweet/etc GFS output beyond day 7 should have 1) a limited set of graphics available with the option to 2) contribute a nominal fee to get a full suite of products while improving future GFS output. #EURObusinessfor-the-win
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ClicheVortex2014
post Mar 19 2017, 02:28 AM
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Definitely off to a very strong start this year. The "hiccup" the first half of the month seems to have just been a brief thing as it looks like we're reverting back to the same pattern we saw in January and February.

From a weather enthusiast perspective, I would preface that sentence with "thankfully"... but as a human, it renews my worry about the potential for this spring. The kind of pattern we've seen this year and what we're seeing return is pretty nasty and has already been very deadly. Obviously something like 2011 is not likely to happen... perhaps even in any of our lifetimes (and I'm among the youngest members on the forum)... but I feel like this could be a very deadly year for severe weather. Lightning, wind, tornadoes, maybe even heat in the summer. It's been relatively tame for the past 5 years, I feel like we're about to pay for it.

This post has been edited by ClicheVortex2014: Mar 19 2017, 02:37 AM


--------------------
Meteorology undergrad at Ohio University

Historic weather events in the Ohio Valley:
- The 1974 Super Outbreak (read more)
- The 2012 "Super" Derecho
- The Great Blizzard of 1978
- ILN Severe Weather Climatology

2017 Weather for Cincinnati

Days >90: 0 (Last: 9/8/16)
Marginal risks: 3 (Last: 3/20/17)
Slight risks: 0 (Last: 9/10/16)
Enhanced risks: 3 (Last: 3/1/17)
Moderate risks: 0 (Last: 6/22/16)
High risks: 0 (Last: 11/17/13)

Realtime Weather on Campus: http://www.phy.ohiou.edu/~scalia/state_street/upload.png
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