jrips27 Posted April 24, 2011 Share Posted April 24, 2011 I have a feeling this thread is going tp get alot busier over the next few days. Link to comment Share on other sites More sharing options...
VAwxman Posted April 24, 2011 Share Posted April 24, 2011 I have a feeling this thread is going tp get alot busier over the next few days. No doubt. As I posted in the central forum, at least per GFS / Euro modeling, this is as alarming of a setup as I have seen in awhile. Lots can change of course which could keep it from being a big deal, but I do not like seeing a late April style 500 mb jet core punching squarely into a solidly juiced warm sector. Link to comment Share on other sites More sharing options...
FoothillsNC Posted April 24, 2011 Share Posted April 24, 2011 No doubt. As I posted in the central forum, at least per GFS / Euro modeling, this is as alarming of a setup as I have seen in awhile. Lots can change of course which could keep it from being a big deal, but I do not like seeing a late April style 500 mb jet core punching squarely into a solidly juiced warm sector. agreed. Just seen the new 00z NAM..as bad as it usually is at that hour, it agrees nicely on a lot of things. A screaming Pac. jet with strong channeled vort max and a sudden developing Arklatex, or Ozarks Low by 84 hours, by then though there will already be some (likely) historic flooding. Then the 850 low wraps up in a split flow, so the table is completely open to an anomalous strong system, couple that with all the synoptic factors and time of year, and this is a DOOZY of a system. At first, the flooding in the corn belt, then the severe outbreak that certainly looms right after. Discrete tornado profiles already showing up, and the synoptics support them in western TN, northenr Miss, ArK and western KY. I have zero doubt this is going to be a very memorable event for a large chunk of real estate. We need a couple of runs yet to see how bad it can be for the southeast, but areas west of the Apps already look bad, and with a neg. tilt , strong dynamic system coming right after this period for the Tn Valley and eventually east coast, it can't be much better for us. Link to comment Share on other sites More sharing options...
VAwxman Posted April 24, 2011 Share Posted April 24, 2011 agreed. Just seen the new 00z NAM..as bad as it usually is at that hour, it agrees nicely on a lot of things. A screaming Pac. jet with strong channeled vort max and a sudden developing Arklatex, or Ozarks Low by 84 hours, by then though there will already be some (likely) historic flooding. Then the 850 low wraps up in a split flow, so the table is completely open to an anomalous strong system, couple that with all the synoptic factors and time of year, and this is a DOOZY of a system. At first, the flooding in the corn belt, then the severe outbreak that certainly looms right after. Discrete tornado profiles already showing up, and the synoptics support them in western TN, northenr Miss, ArK and western KY. I have zero doubt this is going to be a very memorable event for a large chunk of real estate. We need a couple of runs yet to see how bad it can be for the southeast, but areas west of the Apps already look bad, and with a neg. tilt , strong dynamic system coming right after this period for the Tn Valley and eventually east coast, it can't be much better for us. Yeah looks right now like Wednesday would be the potential big day in the SE quad of the U.S. Some images from the new NAM (keeping in mind the exact location of features will change before then): Mid 60s dew into much of TN, with S to SSE sfc flow. Some drier mid level air working in... and also notice the wind direction. That's a ton of directional shear in the lowest 3km. This shows the 500 mb jet I referred to... Solid jet core punching into the warm sector. Lastly, looking at the shear vectors, they are running perpendicular to the trailing cold front, which usually indicates better potential for a discrete mode rather than quickly "lining out". Link to comment Share on other sites More sharing options...
FoothillsNC Posted April 24, 2011 Share Posted April 24, 2011 Yeah looks right now like Wednesday would be the potential big day in the SE quad of the U.S. Some images from the new NAM (keeping in mind the exact location of features will change before then): Mid 60s dew into much of TN, with S to SSE sfc flow. Some drier mid level air working in... and also notice the wind direction. That's a ton of directional shear in the lowest 3km. This shows the 500 mb jet I referred to... Solid jet core punching into the warm sector. Lastly, looking at the shear vectors, they are running perpendicular to the trailing cold front, which usually indicates better potential for a discrete mode rather than quickly "lining out". the shear looks excellent in the TN valley/Miss. Valley , although how much instability remains to be seen. But the shear has ruled it seems like even against the negating factors this season, so my money is on the pattern. A rapid deepening sfc low and such a deep/far south Trough for April with a strong Bermuda ridge in a very dynamic setup is an alarm bell. This is a double whammy for western TN and KY regions for sure, after the initial flood concerns to deal with a severe outbreak. Also, the 200mb jet pattern showed a couple of strong jetstreaks, not to mention the strong diffluent pattern over the Apps of n. Ga and western Carolinas to VA. Link to comment Share on other sites More sharing options...
snowman22 Posted April 24, 2011 Share Posted April 24, 2011 Would this be more of a midsouth event or a gulf coast event. Link to comment Share on other sites More sharing options...
FoothillsNC Posted April 24, 2011 Share Posted April 24, 2011 Would this be more of a midsouth event or a gulf coast event. with the dynamics in play , probably a mid South event but the chance that the line extends well south. Link to comment Share on other sites More sharing options...
LithiaWx Posted April 24, 2011 Share Posted April 24, 2011 It seems that the main factors in play will be stronger in AR/MS/TN/KY areas... Do things seem like they will be near or as active in AL/GA/SC/NC areas? Link to comment Share on other sites More sharing options...
Gastonwxman Posted April 24, 2011 Share Posted April 24, 2011 It seems that the main factors in play will be stronger in AR/MS/TN/KY areas... Do things seem like they will be near or as active in AL/GA/SC/NC areas? Right now it doesn't seem to be nearly as bad as it will be further west, considering timing and the evolution of the system as it progresses eastward. Still, this doesn't eliminate the fact that we will have our fair share of very rough storminess once it moves into our neck of the woods with plenty of wind, hail, heavy rain, and of course scattered tornadic action. Speaking of such, I'm just absolutely blown away by the new 0z GFS data. Lift index values are at an extreme level from eastern OK to western TN with CAPE between 2000-3000 (isolated areas a tad higher) with very steep lapse rates during the 72 hour. The jet structure still looks impressive, perhaps just a tad stronger on this run compared to the previous 0z. Blog update: http://gwxmanblog.bl...jor-system.html EDIT: Western/Central NC/SC now in the slight risk. http://www.spc.noaa....y3otlk_0730.gif An example from sounding data per 0z GFS of LIT, AR: Link to comment Share on other sites More sharing options...
buckeyefan1 Posted April 24, 2011 Share Posted April 24, 2011 agreed. Just seen the new 00z NAM..as bad as it usually is at that hour, it agrees nicely on a lot of things. A screaming Pac. jet with strong channeled vort max and a sudden developing Arklatex, or Ozarks Low by 84 hours, by then though there will already be some (likely) historic flooding. Then the 850 low wraps up in a split flow, so the table is completely open to an anomalous strong system, couple that with all the synoptic factors and time of year, and this is a DOOZY of a system. At first, the flooding in the corn belt, then the severe outbreak that certainly looms right after. Discrete tornado profiles already showing up, and the synoptics support them in western TN, northenr Miss, ArK and western KY. I have zero doubt this is going to be a very memorable event for a large chunk of real estate. We need a couple of runs yet to see how bad it can be for the southeast, but areas west of the Apps already look bad, and with a neg. tilt , strong dynamic system coming right after this period for the Tn Valley and eventually east coast, it can't be much better for us. The NAM gives me .14 and the GFS has .15(it has been around the 1" mark)........Looks like another famous Carolina split for the midlands Watching and waiting patiently for the next edition of As the Models Turn Link to comment Share on other sites More sharing options...
jrips27 Posted April 24, 2011 Share Posted April 24, 2011 Day 3 Day 4 Link to comment Share on other sites More sharing options...
FoothillsNC Posted April 24, 2011 Share Posted April 24, 2011 There's a 130+ mph jetstreak that places the TN valley and Apps then Carolinas in enhanced lift, as it pulls due north. The SFC low deepens as it tracks from central ARK to western TN , then shoots north toward Detroit or northern Ohio. During this process, the intial band of tornado probability will shift from ahead of the best shear in much of western TN stretching west to east, then orient more north to south, roughly northern MS, AL and toward central KY. By midnight that line will be approaching eastern TN, KY , Wva, western VA and western Carolinas to extreme N. GA. Then around sunrise the occluded low will probably do like the early April event and pull a thin line of severe toward northern NC and northward up into PA. It looks extremely similar in timing to the April 6 event overall, and the 5H turns neg. in almost the exact same spot. the red zone is where I think the best chance of TOR will be. Link to comment Share on other sites More sharing options...
jburns Posted April 24, 2011 Share Posted April 24, 2011 the red zone is where I think the best chance of TOR will be. Ouch. Fourth day pretty much centered on me. Link to comment Share on other sites More sharing options...
FoothillsNC Posted April 24, 2011 Share Posted April 24, 2011 Ouch. Fourth day pretty much centered on me. once again for NC, the timing of arrival is probably midnight or so for the mtns and foothills, and dawn or slightly predawn for the central piedmont, give or take a few hours. Its within GFS good zone of 72 to 96 hours and looked similar to ECMWF but it was slower by 6 hours I think. GFS and NAM are extremely similar at 84 hours. The sudden lurch north of the s/w as it rounds the base of the neg. trough in central TN and northern Ala, KY area just west of the Apps looks extremely dangerous to me. To be honest it looks like an exceptional tornado outbreak in the TN valley. Link to comment Share on other sites More sharing options...
eyewall Posted April 24, 2011 Share Posted April 24, 2011 once again for NC, the timing of arrival is probably midnight or so for the mtns and foothills, and dawn or slightly predawn for the central piedmont, give or take a few hours. Its within GFS good zone of 72 to 96 hours and looked similar to ECMWF but it was slower by 6 hours I think. GFS and NAM are extremely similar at 84 hours. The sudden lurch north of the s/w as it rounds the base of the neg. trough in central TN and northern Ala, KY area just west of the Apps looks extremely dangerous to me. To be honest it looks like an exceptional tornado outbreak in the TN valley. Yeah this one doesn't seemed to be timed right for NC but of course I am sure not too many are disappointed with that notion . Link to comment Share on other sites More sharing options...
rosie Posted April 24, 2011 Share Posted April 24, 2011 I did not like the early April event at all, one of the worst I have seen in the past 10+ years and I do not want a repeat! Link to comment Share on other sites More sharing options...
Snowless in Carrollton Posted April 24, 2011 Share Posted April 24, 2011 Foothills, judging by that map it looks like Atlanta is in the clear. It's interesting that you say the timing of arrival for the central piedmont is dawn or predawn, yet you have them shaded in red, while areas like Atlanta and areas along the AL border are not shaded in red and timing will be more favorable for these areas. Link to comment Share on other sites More sharing options...
FoothillsNC Posted April 24, 2011 Share Posted April 24, 2011 Foothills, judging by that map it looks like Atlanta is in the clear. It's interesting that you say the timing of arrival for the central piedmont is dawn or predawn, yet you have them shaded in red, while areas like Atlanta and areas along the AL border are not shaded in red and timing will be more favorable for these areas. well a lot of times the nighttime ones east of the Apps do diminish, like the last event, but the one before it they didn't. It was a strong derecho type event, anda lot of factors have to be looked at to see which we have. But to me it appears this one more looks like a blend of the previous 2 events. The early April one had a strong 5H neg trough arriving around evening or after midnight for GA and Carolinas, but was further south than this one is progged to be, so that would argue for less in the way of severe here, but if the timing is off a little, then the developed line could easily survive well after dark and even through the night east of the Apps. Just because its at night doesnt' automatically mean it will def. decay, there's still plenty going for it to remain in tact. The surface low and trough seems to get closer each run with the GFS, but I do think its worst will be the west side of the Apps right now. Subject to change of course. Link to comment Share on other sites More sharing options...
FoothillsNC Posted April 24, 2011 Share Posted April 24, 2011 the ECMWF is blowing the repeating rains over the corn belt now. Through 24 hours it only has .75" ro 1" where already the last few hours a large section of Ark, Ok, Ky, nw TN and MO have had several inches. Also, it forecasts on 2 to 3" over the next 48 hours, once again, ther will be way more than that. I've noticed the ECMWF is terrible in the short range on big precip events. But that said, its 5h look is similar for the Wed night and thur event here, very similar to GFS and NAM in a lot of factors. The least trustworthy aspect is its rain..nam and GFS blow it away. Link to comment Share on other sites More sharing options...
ATL_Militarypolice Posted April 24, 2011 Author Share Posted April 24, 2011 Analogs on SPC MARS. Link to comment Share on other sites More sharing options...
Gastonwxman Posted April 24, 2011 Share Posted April 24, 2011 the ECMWF is blowing the repeating rains over the corn belt now. Through 24 hours it only has .75" ro 1" where already the last few hours a large section of Ark, Ok, Ky, nw TN and MO have had several inches. Also, it forecasts on 2 to 3" over the next 48 hours, once again, there will be way more than that. I've noticed the ECMWF is terrible in the short range on big precip events. But that said, its 5h look is similar for the Wed night and thur event here, very similar to GFS and NAM in a lot of factors. The least trustworthy aspect is its rain..nam and GFS blow it away. Always seems to be the case indeed. I can still see areas like northern AR or western TN getting more than 6 inches of rain out of this with devastating flooding occurring along the MS river. This will be one for the books for one of the worst flooding scenarios ever to occur amongst all the severe storms and tornadoes back west. Absolutely incredible of what this pattern is intending to yield for the last week of this month. The way things are evolving now, I suspect early May will keep this up with one storm system after another developing back west until things begin to calm some for a while. It's going to be a wild ride for sure once we get things initiated during mid week. Link to comment Share on other sites More sharing options...
Snowless in Carrollton Posted April 24, 2011 Share Posted April 24, 2011 well a lot of times the nighttime ones east of the Apps do diminish, like the last event, but the one before it they didn't. It was a strong derecho type event, anda lot of factors have to be looked at to see which we have. But to me it appears this one more looks like a blend of the previous 2 events. The early April one had a strong 5H neg trough arriving around evening or after midnight for GA and Carolinas, but was further south than this one is progged to be, so that would argue for less in the way of severe here, but if the timing is off a little, then the developed line could easily survive well after dark and even through the night east of the Apps. Just because its at night doesnt' automatically mean it will def. decay, there's still plenty going for it to remain in tact. The surface low and trough seems to get closer each run with the GFS, but I do think its worst will be the west side of the Apps right now. Subject to change of course. Even though the best chance for tornadoes may be west of the Apps it still wouldn't shock me if there is a a tornado or two in the Atlanta area and East Alabama. Link to comment Share on other sites More sharing options...
FoothillsNC Posted April 24, 2011 Share Posted April 24, 2011 Even though the best chance for tornadoes may be west of the Apps it still wouldn't shock me if there is a a tornado or two in the Atlanta area and East Alabama. the line will probably extend to ATL and may be broken south of that, I don't know. This is such an explosive setup right at 78 to 84 hours, that the models will have a hard time, but I do say that synoptically, regardless what any models show, there will more than likely be tornadoes in TN and possibly south and north in the adjacent states. Look what NAM does at 78 hours just when the surface low is leaving western TN heading to north of Nashville, when the strong next vort arrives. A sudden squall line development under extreme shear most likely. Thats about the time all the models have the jet streak and vort taking the north turn, causing strong lift through the diffluent aloft/ LLconvergence. So at 84 hours is when the line will be approaching ATL. Link to comment Share on other sites More sharing options...
dwagner88 Posted April 24, 2011 Share Posted April 24, 2011 People out towards Memphis are preparing for a repeat of the may floods last year. They are under a rare PDS flash flood watch. Link to comment Share on other sites More sharing options...
Snowless in Carrollton Posted April 24, 2011 Share Posted April 24, 2011 FFC is saying it looks like a night time event. Why on earth does every single storm system come through this area at night ? It's like dejavu all over again, time after time. Link to comment Share on other sites More sharing options...
GaWx2688 Posted April 24, 2011 Share Posted April 24, 2011 Well west Ga is already in that 35% area for severe weather, so we shall see how this one pans out for our area. Link to comment Share on other sites More sharing options...
audioguy3107 Posted April 25, 2011 Share Posted April 25, 2011 FFC is saying it looks like a night time event. Why on earth does every single storm system come through this area at night ? It's like dejavu all over again, time after time. Usually around here during severe weather season it's always a blend when it comes to time of day.....but I'm with you this year, I'm sick of these things coming through at 3 in the morning. Not only is it too late for me to follow the event, it also wakes me up!!! Last week's storm woke up our baby as well. Enough with the overnight crap, let's get something brewing during the heat of the afternoon. Link to comment Share on other sites More sharing options...
ATL_Militarypolice Posted April 25, 2011 Author Share Posted April 25, 2011 SPC MARS has been consistent with November 10, 2002 and November 15-16/89 as two possible analogs. 11/2002 Link to comment Share on other sites More sharing options...
jrips27 Posted April 25, 2011 Share Posted April 25, 2011 SPC MARS has been consistent with November 10, 2002 and November 15-16/89 as two possible analogs. 11/2002 That looks bad. Would be something of anything close to that came to fruition. Link to comment Share on other sites More sharing options...
ATL_Militarypolice Posted April 25, 2011 Author Share Posted April 25, 2011 SPC SREF tornado ingriediants. Keep in mind still 60+ hours out. Link to comment Share on other sites More sharing options...
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