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jaxjagman

Tn Valley Severe Weather 2017

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Deleted the original thread by mistake,found out what moderation actions was :( Wasn't aware it would delete the whole thread,now i know

 

CanSIPS is showing Nina hanging around during March

 

cansips_ssta_noice_global_3.png

 

 

Looks like it could be a stormy April in the Valley if SIPS is close

 

cansips_T2ma_us_4.png

 

 

 

cansips_apcpna_month_us_4.png

 

 

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Probably see a Nina to Nino transition. Do you still have the article that kicked off the other thread? La Nina or Nina to Nino can include active severe. I believe the trend has been set since December, and accounting for the January min. Mid South could see more severe events in the next few/several weeks with the Eastern Valley perhaps later more into spring. Really I do not root for Dixie Alley severe. Oh but the analog years look good in the Plains!

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Should be a shot at seeing some severe weather into Feb.Multiple waves coming out of Asia.The MJO is into 4 ,  into warm phases .The models will be everywhere coming up i'd think in the long range.Not that they ever aren't anyways.

 

ecmwf_z500a_wpac_11.png

 

chi200.cfs.all.global.7.png

 

Either way,expect some rain and possibly alot of it.

 

bsr-opc-00z-05.jpg

 

 

 

 

 

20170130_00z-fcst_valid-2017-02-16.png

 

 

 

 

 

 

 

 

 

 

 

 

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All weeklies are going to some sort of a trough West (or southwest) ridge East (or northeast) the second half of February. Could be late February if mid-Feb gets another cold shot. Some of those clusters would be severe even in Feb. Otherwise it is a little early without everything in place. I will hedge with a few to several weeks away, lol...

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I'd be surprised if you don't see at least a  slight risk tomorrow unless the models totally flip coming up for the Western Valley.The system looks better today further S on the GFS.Euro shows the system into Mid Indiana,better severe risk into the Valley

 

sbcape.conus.png

 

gfs_mslp_uv850_us_22.png

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  Day 4-8 Convective Outlook  
   NWS Storm Prediction Center Norman OK
   0400 AM CST Fri Feb 03 2017

   Valid 061200Z - 111200Z

   ...DISCUSSION...
   Substantial run-to-run and model-to-model variability is once again
   evident within the latest medium-range model runs, even as early as
   late in the Day 4 (Monday) time frame.  In an overall/very broad
   perspective, convective potential should begin to increase across
   roughly the mid-Mississippi/Ohio Valleys late Day 4, then spreading
   across the Ohio and Tennessee Valleys and possibly the central Gulf
   coastal region Day 5 (Tuesday), and finally across the Appalachians
   and East Coast States during the day Wednesday (Day 6).  This will
   occur as short-wave troughing shifts out of the Rockies and eastward
   into the eastern half of the U.S. where amplification into a
   larger-scale trough is expected to occur.  Corresponding evolution
   of a surface storm system which will progress eastward across the
   region will likely allow fairly widespread warm-sector showers and
   thunderstorms to occur during this roughly 48-hour time period.

   With that said, confidence in the ability to highlight specific
   areas -- and degree -- of risk remains low, due to the
   aforementioned difficulty exhibited by the models in depicting a
   consistent evolution of the pertinent features -- both at the
   surface and aloft.  While at least a low-probability severe risk
   will likely be highlighted in future outlooks within an area roughly
   bounded by the Mississippi and Ohio River Valleys on the north and
   west, and the Atlantic and Gulf coasts on the south and east, in the
   late Monday through Wednesday afternoon time frame,
   uncertainty/predictability issues preclude areal highlights at this
   time.

20170203_00z-fcst_valid-2017-02-07.png

 

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Euro is still more aggressive.Capes over 1800 Memphis,even around 500 TYS,CHA700,BNA 1000.Steep lapse rates over 7 for all of the Valley,even 8 around the KY and Tn border.Impressive winter severe storm potential for this time of season in the Valley IF it holds.

Loading Maps...

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Difference between the 0z GFS and Euro isnt that far off,The GFS is showing a tilted system while the Euro isn't,this should be why you see more instability with the Euro,either could be right at this point.But both show severe into the Valley,it's just the extremes right now

 

gfs_z500_mslp_us_15.png

 

 

ecmwf_z500_mslp_us_5.png

 

 

 

 

 

 

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 Day 4-8 Convective Outlook  
   NWS Storm Prediction Center Norman OK
   0338 AM CST Sat Feb 04 2017

   Valid 071200Z - 121200Z

   ...DISCUSSION...
   Model differences/uncertainty persist at this time, with respect to
   evolution of the large surface storm system to move across the
   eastern third of the U.S. Day 4/Tuesday.  However a somewhat more
   consistent depiction of major features within the ECMWF and GFS
   permits what appears to be a reasonable ability to highlight a 15%
   severe risk area from roughly the mid Ohio Valley southward into the
   central Gulf coastal region.  Within this area, somewhat modest but
   sufficient CAPE development should occur ahead of a
   strengthening/advancing cold front -- particularly from the Ohio
   Valley southward -- to permit development of fairly robust updrafts
   by afternoon.  Though what appears likely to be a westerly component
   to the low-level warm-sector flow field should limit tornado
   potential, large hail and locally damaging winds will be possible --
   with potential for both rotating storms and lines/line segments. 
   Convection should eventually weaken overnight, especially over
   northern parts of the risk area as storms move into a less-unstable
   environment.  Risk may linger farther south, as storms move into the
   southern Appalachians overnight.

   By Day 5/Wednesday, greater uncertainty exists, with the GFS
   depicting the front to have moved off the Atlantic and Gulf coasts
   by midday, while the ECMWF lingers a trailing, west-to-east portion
   of the front over the Gulf Coast States/Carolinas through the
   afternoon.  Given these differences, will not highlight a risk area
   at this time for Day 5.

   Risk appears minimal for Day 6, but potential for convection could
   increase into the central U.S. Day 7 and into the East Day 8 as the
   next storm system shifts out of the Rockies.  Model differences are
   substantial enough with respect to the details, however, that no
   risk areas will be considered at this time.

   ..Goss.. 02/04/2017

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 Day 3 Convective Outlook  
   NWS Storm Prediction Center Norman OK
   0226 AM CST Sun Feb 05 2017

   Valid 071200Z - 081200Z

   ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE MID
   MISSISSIPPI/OHIO/TENNESSEE VALLEYS AND VICINITY...

   ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS SURROUNDING THE
   SLIGHT RISK AREA...

   ...SUMMARY...
   Showers and scattered thunderstorms are forecast to affect the mid
   Mississippi, Ohio, and Tennessee Valley areas, and later spreading
   eastward across the Appalachians.  Isolated strong/locally severe
   storms will be possible mainly west of the mountains.

   ...Synopsis...
   Progression of low-amplitude upper short-wave troughing across the
   eastern half of the country is expected Day 3, with an associated
   surface low forecast to deepen gradually as it shifts northeastward
   from the IL/IN vicinity early, across the Great Lakes and eventually
   to the Ottawa River Valley area late.  As the low progresses, a
   trailing cold front will shift east across the Midwest and
   eventually the Appalachians, and southeast into the central Gulf
   coastal states by the end of the period.  Showers and scattered
   thunderstorms will accompany this storm system.

   ...Mid MS/OH/TN Valleys and vicinity...
   A complex scenario remains evident for Day 3/Tuesday, with model
   differences still evident and corresponding low confidence with
   respect to forecast details of convective mode/intensity/evolution
   ahead of the advancing cold front.

   Showers and scattered storms (and possibly local/low-end severe
   risk) should be ongoing at the start of the period, and should
   continue through the day in many areas.  This suggests that
   potential for diurnal destabilization will be limited across much of
   the region.  Still, advance of the upper system and associated
   surface cold front should support some potential for intensification
   of storms during the afternoon, aided by favorably strong flow
   aloft.  Greatest severe risk at this time -- largely in the form of
   gusty/damaging winds -- appears likely to exist from the mid Ohio
   Valley southward across the Tennessee Valley.  Threat should
   diminish during the evening across northern parts of the risk area
   as storms cross the Ohio Valley.  Convection -- and some severe risk
   -- may linger farther south, as the front settles southward into the
   central Gulf Coast States overnight.

   ..Goss.. 02/05/2017

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Regarding severe potential, there will be low to moderate CAPE
Tuesday midday and afternoon, with somewhat strong winds fields.
But, the best lift, max heating, and low level jet are not in
phase. So, there continues to be potential for severe storms with
our area under SPC`s slight risk. But, we are looking at a lower
severe potential than we would have if all the parameters came
together at the right time. Damaging straight line winds continue
to be the main concern, with some potential for large hail. Wind
fields suggest a low tornado threat.

http://forecast.weather.gov/product.php?site=OHX&issuedby=OHX&product=AFD&format=CI&version=1&glossary=1

 

Agree with OHX.Hoping we get some good thunder,anywaysThe GFS has some better showalter,especially down to the TN and Al line,even some -3 down that way.We haven't had a good storm here in Mid Tn  since winter of of '15.Models are showing loss of diurnal heating the severe threat decreases rapidly in the Valley like the SPC mentions in the above post

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Still looks like a good threat coming up.Looking like a big storm coming out of East Asia

 

ecmwf_z500a_wpac_3.png

 

Teleconnection shows the PNA breaking down mid month

 

4indices.png

 

 

Dashboard has been showing it now for several days

 

20170207_00z-fcst_valid-2017-02-20.png

 

 

http://www.spc.noaa.gov/exper/CFS_Dashboard/

 

Bad news for those along the Gulf Coast into the Mid-Mississippi and Tennessee Valley's.

http://blog.organicforecasting.com/2017/02/severe-weather-signals.html

 

 

We'll see

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Day 1 Convective Outlook  
   NWS Storm Prediction Center Norman OK
   0700 AM CST Wed Feb 08 2017

   Valid 081300Z - 091200Z

   ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS EASTERN TN
   AND NEARBY APPALACHIANS VICINITY...

   ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM THE TN
   VALLEY TO THE CAROLINAS AND SOUTHERN VIRGINIA...

   ...SUMMARY...
   Isolated severe thunderstorms may develop this afternoon and early
   evening across parts of the Tennessee Valley and southern
   Appalachians, continuing eastward into the Carolinas and southern
   Virginia tonight.

   ...TN Valley/Appalachians to Carolinas and southern VA...
   An upper trough (and related speed max) currently over the
   north-central Plains/middle MO Valley will continue to amplify and
   steadily progress east-southeastward toward the TN Valley and
   Appalachians tonight. A cold front will advance generally
   east-southeastward across the TN Valley and central/southern
   Appalachians through tonight, with a frontal wave expected to
   gradually deepen and steadily progress east/northeastward late this
   afternoon into tonight.

   While the boundary layer will not be particularly moist (50s F
   surface dewpoints in many areas) or unstable ahead of the cold
   front, relatively cool mid-level thermal profiles, related steep
   lapse rates aloft should support some stronger/sustained updrafts
   this afternoon. This would most likely initially occur across parts
   of eastern TN and nearby southeast KY and far northern portions of
   AL/GA. Relatively long/generally straight hodographs could support
   some initial lower-topped splitting storms/supercells with a severe
   hail risk, with storms subsequently spreading eastward toward/across
   the Appalachians this evening with at least some hail/localized
   damaging wind risk.

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Low clouds today are a pity. With cool mid-levels could have seen a few fun hailers. Unidirectional winds could have mixed down locally (straight), but alas none of the above is likely.

Ensembles have a system going through Dixie Alley in the 11-15 day period, same period as the Dashboard above. 

Finally I found another version of the TNI Trans-Nino-Index paper about transitions between La Nina and El Nino and vice versa. TNI_Tornadoes by Lee et. al. Many smart minds gathered from universities, NOAA and other agencies.

Previous research showed La Nina more active than normal from the Plains to Southeast. El Nino was found somewhat active early Deep South and active late Upper Midwest late, but a little quiet central Tornado Alley. However correlations are weak, esp if not considering ENSO evolution with time from fall/winter into the spring of concern.

New TNI research shows El Nino ending early may offer slightly more activity than persistent Nino. La Nina is still shown active Midwest to Southeast. However decaying La Nina may be most active from the Southern/Central Plains to Midwest, traditional Tornado Alley. TNI correlation coefficients are stronger than those of ENSO alone, but still not particularly high.

We are in decaying La Nina. Persistence and the March chart show Dixie could have some early activity. However the stronger signal is Plains and Midwest April and May. I really do not root for Dixie Alley, and I'm very happy to travel home for the chase.

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6 hours ago, nrgjeff said:

Low clouds today are a pity. With cool mid-levels could have seen a few fun hailers. Unidirectional winds could have mixed down locally (straight), but alas none of the above is likely.

Ensembles have a system going through Dixie Alley in the 11-15 day period, same period as the Dashboard above. 

Finally I found another version of the TNI Trans-Nino-Index paper about transitions between La Nina and El Nino and vice versa. TNI_Tornadoes by Lee et. al. Many smart minds gathered from universities, NOAA and other agencies.

Previous research showed La Nina more active than normal from the Plains to Southeast. El Nino was found somewhat active early Deep South and active late Upper Midwest late, but a little quiet central Tornado Alley. However correlations are weak, esp if not considering ENSO evolution with time from fall/winter into the spring of concern.

New TNI research shows El Nino ending early may offer slightly more activity than persistent Nino. La Nina is still shown active Midwest to Southeast. However decaying La Nina may be most active from the Southern/Central Plains to Midwest, traditional Tornado Alley. TNI correlation coefficients are stronger than those of ENSO alone, but still not particularly high.

We are in decaying La Nina. Persistence and the March chart show Dixie could have some early activity. However the stronger signal is Plains and Midwest April and May. I really do not root for Dixie Alley, and I'm very happy to travel home for the chase.

Awesome !! I found another paper from them with a video

 

https://www.gfdl.noaa.gov/research_highlight/u-s-regional-tornado-outbreaks-and-their-links-to-spring-enso-phases-and-north-atlantic-sst-variability/

 

 

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Looks like Nina is history

 

EL NIÑO/SOUTHERN OSCILLATION (ENSO)
DIAGNOSTIC DISCUSSION
issued by
CLIMATE PREDICTION CENTER/NCEP/NWS
and the International Research Institute for Climate and Society
09 February 2017
 

ENSO Alert System Status: Final La Niña Advisory

 

Synopsis:  ENSO-neutral conditions have returned and are favored to continue through at least the Northern Hemisphere spring 2017.

La Niña conditions are no longer present, with slightly below-average sea surface temperatures (SSTs) observed across the central equatorial Pacific and above-average SSTs increasing in the eastern Pacific [Fig. 1]. The latest weekly Niño index values were -0.3°C in the westernmost Niño-4 and Niño-3.4 regions, and +1.5°C in the easternmost Niño-1+2 region [Fig. 2]. The upper-ocean heat content anomaly increased during January and was slightly positive when averaged across the eastern Pacific [Fig. 3], a reflection of above-average temperatures at depth [Fig. 4]. Atmospheric convection remained suppressed over the central tropical Pacific and enhanced over Indonesia [Fig. 5]. The low-level easterly winds were slightly enhanced over the western tropical Pacific, and upper-level westerly winds were near average. Overall, the ocean and atmosphere system is consistent with ENSO-neutral conditions.

Most models predict the continuation of ENSO-neutral (3-month average Niño-3.4 index between -0.5°C and 0.5°C) through the Northern Hemisphere summer [Fig. 6]. However, a few dynamical model forecasts, including the NCEP CFSv2, anticipate an onset of El Niño as soon as the Northern Hemisphere spring (March-May 2017). Because of typically high uncertainty in forecasts made at this time of the year for the upcoming spring and summer, and the lingering La Niña-like tropical convection patterns, the forecaster consensus favors ENSO-neutral during the spring with a ~60% chance. Thereafter, there are increasing odds for El Niño toward the second half of 2017 (~50% chance in September-November). In summary, ENSO-neutral conditions have returned and are favored to continue through at least the Northern Hemisphere spring 2017 (click CPC/IRI consensus forecast for the chance of each outcome for each 3-month period).

This discussion is a consolidated effort of the National Oceanic and Atmospheric Administration (NOAA), NOAA's National Weather Service, and their funded institutions. Oceanic and atmospheric conditions are updated weekly on the Climate Prediction Center web site (El Niño/La Niña Current Conditions and Expert Discussions). Forecasts are also updated monthly in the Forecast Forum of CPC's Climate Diagnostics Bulletin. Additional perspectives and analysis are also available in an ENSO blog. The next ENSO Diagnostics Discussion is scheduled for 09 March 2017 . To receive an e-mail notification when the monthly ENSO Diagnostic Discussions are released, please send an e-mail message to: [email protected].

 
Climate Prediction Center
National Centers for Environmental Prediction
NOAA/National Weather Service
College Park, MD 20740

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Since the last quarter century there was two notable out breaks in May in both 2003(ONI during May -.02) and 2004(ONI+.02) when the enso was neutral

able 1: Notable Tornado Outbreaks - 1900-2011

Date Tornadoes Fatalities Location ENSO Phase
April, 1908 >41 324 Central-Southeastern US La Niña
May-June, 1917 >78 383 Central-Southeastern US La Niña
March 18, 1925 9 >747 Mississippi Valley-Ohio Valley Neutral
May, 1930 >90 110 Great Plains, Mississippi Valley El Niño
March 21-22, 1932 >20 >330 Southeastern US El Niño
April 5-6, 1936 17 >436 Southeastern US Neutral
March-May 1942 - >270 Great Plains El Niño
April 9-10, 1947 8 181 Southern Great Plains Neutral
May, 1949 >82 66 Central-Southeastern US Neutral
April-May 1953 33 >144 Southern Great Plains, Upper MS Valley El Niño
April 11-12, 1965 51 265 Central US Neutral
April 3-4, 1974 148 330 Eastern US La Niña
April 2-3, 1982 61 29 Southern Plains-Mississippi Valley Neutral
May 31, 1985 43 88 US-Canada, Eastern Great Lakes La Niña
May 1995 391 11 Central and Southern US El Niño
April-May 1999 140 50 Southern Great Plains La Niña
May 2003 543 >48 Southern Great Plains, Midwest, Southeast US Neutral
May 2004 384 7 Great Plains-Midwest Neutral
May 2008 >100 >40 Great Plains, Mississippi Valley, Southeast La Niña
April 2011 875 361 Southeast US La Niña

 

https://www.esrl.noaa.gov/psd/csi/events/2011/tornadoes/enso.html

 

enso_percentage-of-annuial-monthhttp://www.ustornadoes.com/2016/03/30/how-does-el-nino-la-nina-or-la-nada-impact-the-following-tornado-season/

 

 

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All great posts above. I am fairly confident forecasting 2017 will be fairly active. Now I am not necessarily forecasting all that weather in the Southeast. Strong persistent La Nina would correlate here, but decaying/dead Nina (2017) correlates to near normal in the Southeast. 

Decaying La Nina is the bin I in which I place 2017. Sure the SSTs have reached neutral. Atmosphere continues Nina-ish from the tropical Pacific to North America. Decaying phase makes sense to me. I am looking for Great Plains great action this year.

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Shortening the time horizon today, the week of February 20 looks like a pattern match for severe weather in the South. Now it may be Deep South, not us, but evidence is increasing. Of course 11-15 day daily forecasts are rubbish, but weeklies add value that period. Both are super mild with an active southern stream starting in California. CFS stays quiet Southeast, but I believe blows the 500 mb pattern. Euro weeklies have a consistent trough plowing through the Southern US (Calif. to Southeast) with above normal Southeast precip. Separately all ensembles have a system tracking through the South, even with track differences. Dashboard above could score a win.

I can't resist going into week 3-4, March madness what the heck. CFS stays active even though details are literally all over the place run-to-run. Euro weeklies are more steady with trough west ridge east. OK the trough is more Rockies/Plains, but this year that still pumps up heights and temps in the Southeast. If you believe the TNI is in decaying La Nina, March is the more active than normal month Southeast (still not April/May absolute levels). April/May active anomaly quickly goes to the Plains/Midwest. April/May is near normal Southeast. While I do not root for Dixie Alley severe, I will certainly take interest in severe anytime and anywhere.

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21 hours ago, nrgjeff said:

Shortening the time horizon today, the week of February 20 looks like a pattern match for severe weather in the South. Now it may be Deep South, not us, but evidence is increasing. Of course 11-15 day daily forecasts are rubbish, but weeklies add value that period. Both are super mild with an active southern stream starting in California. CFS stays quiet Southeast, but I believe blows the 500 mb pattern. Euro weeklies have a consistent trough plowing through the Southern US (Calif. to Southeast) with above normal Southeast precip. Separately all ensembles have a system tracking through the South, even with track differences. Dashboard above could score a win.

I can't resist going into week 3-4, March madness what the heck. CFS stays active even though details are literally all over the place run-to-run. Euro weeklies are more steady with trough west ridge east. OK the trough is more Rockies/Plains, but this year that still pumps up heights and temps in the Southeast. If you believe the TNI is in decaying La Nina, March is the more active than normal month Southeast (still not April/May absolute levels). April/May active anomaly quickly goes to the Plains/Midwest. pril/May is near normal Southeast. While I do not root for Dixie Alley severe, I will certainly take interest in severe anytime and anywhere.

Agree,See what mesoscale we can play with for 20th.Another system around the 26th via Euro in Asia and dashboard.

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I had a little spare time to look up Super Outbreak stats. Living in north Alabama, this one caught my eye the most:
Alabama has been involved in three Super Outbreaks - 1932,1974 and 2011 and has suffered 606 fatalities combined in those three outbreaks. I think we should be given a lifetime pass for any future Super Outbreaks.

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The models keep hinting at a strong short wave the week after next towards the Gulf Coast region.Not sure what to think of the Valley right yet.But this could be more of strong storms further south of us,It's starting to show signs of a multi day event depending on which model you believe

pivotalweather   GFS   500 mb Height  Vorticity for Wed 2017 02 22 00z.png

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Euro looks much warmer in the 850's on the 0Z run. though some of the  better convection is lagging behind(capes).Sure we haven't seen the last change.

 

 Day 4-8 Convective Outlook  
   NWS Storm Prediction Center Norman OK
   0322 AM CST Mon Feb 13 2017

   Valid 161200Z - 211200Z

   ...DISCUSSION...
   This evening's runs of the GFS and ECMWF are depicting similar
   solutions with respect to evolution of synoptic features through Day
   6/Saturday.  After Day 6, solutions become increasingly divergent,
   mainly with respect to evolution/progression of a large-scale trough
   into/across the central third of the U.S. through the end of the
   period.  

   The progression of this trough would likely result in an increase in
   thunderstorm potential, and possibly some associated severe risk. 
   However, significant differences in the model solutions preclude any
   confident assessment of the potential risk.

   Prior to this, a much smaller-scale perturbation in the southern
   stream is forecast move out of Mexico into the southern Plains Day
   4/Thursday, and then steadily eastward across the lower- and
   mid-Mississippi/Tennessee Valleys and Gulf coastal states, before
   reaching the southeast U.S. Day 6.  However, with a frontal
   intrusion into/through the Gulf immediately prior, a cool/dry inland
   boundary layer across the southeast quarter of the country should
   preclude any severe-weather risk with this system.

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19 hours ago, kperk014 said:

I had a little spare time to look up Super Outbreak stats. Living in north Alabama, this one caught my eye the most:
Alabama has been involved in three Super Outbreaks - 1932,1974 and 2011 and has suffered 606 fatalities combined in those three outbreaks. I think we should be given a lifetime pass for any future Super Outbreaks.

We can arrange a pass next week at least. Figures over the weekend after I post a Day 10 forecast on a Friday it fizzles. However that's just as well in North Alabama.

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Possibly some strong storms next Friday.

 

Image

 

Day 4-8 Convective Outlook  
   NWS Storm Prediction Center Norman OK
   0339 AM CST Fri Feb 17 2017

   Valid 201200Z - 251200Z

   ...DISCUSSION...
   The potential for severe weather will likely remain low early during
   the extended period as a mid-level low meanders eastward over the
   Gulf of Mexico and towards the FL Straits.  Time-lagged
   deterministic and ensemble data indicate a potent mid-level trough
   will eject into the Great Plains on Thursday (day 7).  In an
   otherwise very favorable pattern for severe, return-flow moisture
   will likely be limited owing to the aforementioned influence of the
   weather system over the Gulf of Mexico and northerly offshore flow
   over the northwestern Gulf Coast leading up to Thursday.  The
   central U.S. disturbance will subsequently move downstream into the
   MS Valley and possibly lead to an increased risk for an organized
   band or bands of strong to severe thunderstorms on Friday (day 8). 
   Ensemble model exhibit appreciable variability/spread.  Therefore
   will refrain from introducing a 15-percent severe highlight for
   areas downstream of the central-southern Great Plains (MS-OH-TN
   Valleys) and await additional model consistency.

 

gfs-ens_z500a_us_32.png

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