jaxjagman Posted January 29, 2017 Share Posted January 29, 2017 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 Looks like it could be a stormy April in the Valley if SIPS is close Link to comment Share on other sites More sharing options...
jaxjagman Posted January 29, 2017 Author Share Posted January 29, 2017 NMME Prob fcst PAC calib. prob fcst NCEP_CFSv2 CMC1_CanCM3 CMC2_CanCM4 GFDL_FLOR GFDL_CM2.1 NCAR_CCSM4 NASA_GEOS5 NCAR_CESM IMME NMME Prob fcst PAC calib. prob fcst NCEP_CFSv2 CMC1_CanCM3 CMC2_CanCM4 GFDL_FLOR GFDL_CM2.1 NCAR_CCSM4 NASA_GEOS5 NCAR_CESM IMME Some of the seasonals look dry in April Link to comment Share on other sites More sharing options...
jaxjagman Posted January 30, 2017 Author Share Posted January 30, 2017 ElNino,summer time NMME Prob fcst PAC calib. prob fcst NCEP_CFSv2 CMC1_CanCM3 CMC2_CanCM4 GFDL_FLOR GFDL_CM2.1 NCAR_CCSM4 NASA_GEOS5 NCAR_CESM IMME Link to comment Share on other sites More sharing options...
jaxjagman Posted January 30, 2017 Author Share Posted January 30, 2017 1+2 is rather warm this week The latest weekly SST departures are: Niño 4 -0.1ºC Niño 3.4 -0.4ºC Niño 3 0.0ºC Niño 1+2 2.0ºC http://www.cpc.ncep.noaa.gov/products/analysis_monitoring/lanina/enso_evolution-status-fcsts-web.pdf Link to comment Share on other sites More sharing options...
nrgjeff Posted January 30, 2017 Share Posted January 30, 2017 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! Link to comment Share on other sites More sharing options...
jaxjagman Posted January 30, 2017 Author Share Posted January 30, 2017 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. Either way,expect some rain and possibly alot of it. Link to comment Share on other sites More sharing options...
nrgjeff Posted January 30, 2017 Share Posted January 30, 2017 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... Link to comment Share on other sites More sharing options...
jaxjagman Posted February 2, 2017 Author Share Posted February 2, 2017 GFS is looking more like the Euro.Possibly strong storms anyways with that look,especially to the Western Valley.We'll see. Link to comment Share on other sites More sharing options...
jaxjagman Posted February 2, 2017 Author Share Posted February 2, 2017 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 Link to comment Share on other sites More sharing options...
jaxjagman Posted February 3, 2017 Author Share Posted February 3, 2017 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. Link to comment Share on other sites More sharing options...
jaxjagman Posted February 3, 2017 Author Share Posted February 3, 2017 Link to comment Share on other sites More sharing options...
jaxjagman Posted February 3, 2017 Author Share Posted February 3, 2017 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. Link to comment Share on other sites More sharing options...
jaxjagman Posted February 4, 2017 Author Share Posted February 4, 2017 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 Link to comment Share on other sites More sharing options...
jaxjagman Posted February 4, 2017 Author Share Posted February 4, 2017 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 Link to comment Share on other sites More sharing options...
jaxjagman Posted February 5, 2017 Author Share Posted February 5, 2017 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 Link to comment Share on other sites More sharing options...
jaxjagman Posted February 5, 2017 Author Share Posted February 5, 2017 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 Link to comment Share on other sites More sharing options...
jaxjagman Posted February 7, 2017 Author Share Posted February 7, 2017 Still looks like a good threat coming up.Looking like a big storm coming out of East Asia Teleconnection shows the PNA breaking down mid month Dashboard has been showing it now for several days 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 Link to comment Share on other sites More sharing options...
jaxjagman Posted February 8, 2017 Author Share Posted February 8, 2017 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. Link to comment Share on other sites More sharing options...
nrgjeff Posted February 8, 2017 Share Posted February 8, 2017 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. Link to comment Share on other sites More sharing options...
jaxjagman Posted February 9, 2017 Author Share Posted February 9, 2017 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/ Link to comment Share on other sites More sharing options...
jaxjagman Posted February 9, 2017 Author Share Posted February 9, 2017 Looks like Nina is history EL NIÑO/SOUTHERN OSCILLATION (ENSO) DIAGNOSTIC DISCUSSION issued byCLIMATE 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 Link to comment Share on other sites More sharing options...
jaxjagman Posted February 9, 2017 Author Share Posted February 9, 2017 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 http://www.ustornadoes.com/2016/03/30/how-does-el-nino-la-nina-or-la-nada-impact-the-following-tornado-season/ Link to comment Share on other sites More sharing options...
nrgjeff Posted February 9, 2017 Share Posted February 9, 2017 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. Link to comment Share on other sites More sharing options...
nrgjeff Posted February 10, 2017 Share Posted February 10, 2017 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. Link to comment Share on other sites More sharing options...
jaxjagman Posted February 11, 2017 Author Share Posted February 11, 2017 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. Link to comment Share on other sites More sharing options...
kperk014 Posted February 13, 2017 Share Posted February 13, 2017 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. Link to comment Share on other sites More sharing options...
jaxjagman Posted February 13, 2017 Author Share Posted February 13, 2017 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 Link to comment Share on other sites More sharing options...
jaxjagman Posted February 13, 2017 Author Share Posted February 13, 2017 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. Link to comment Share on other sites More sharing options...
nrgjeff Posted February 13, 2017 Share Posted February 13, 2017 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. Link to comment Share on other sites More sharing options...
jaxjagman Posted February 17, 2017 Author Share Posted February 17, 2017 Possibly some strong storms next Friday. 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. Link to comment Share on other sites More sharing options...
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