mempho Posted March 30, 2017 Share Posted March 30, 2017 SPC - Talk about walking it back. That's a massive decrease. Good for us, though. Sent from my SM-G900R7 using Tapatalk Link to comment Share on other sites More sharing options...
Runman292 Posted March 30, 2017 Share Posted March 30, 2017 Here's the latest Discussion from MRX: .LONG TERM (Tonight through Wednesday)...A negative upper trough will move across the Ohio and Tennessee Valleys tonight and early Friday morning. A series of jet streaks exiting the upper trough will produce divergence aloft over the region late today through early Friday morning. These circulation around this jets will enhance the fronto-genetic forcing overnight. Models show the airmass becoming moderately unstable with MLCAPES of 1000-1500 J/Kg with Hail CAPEs of 150-300 J/kg. Shear/SR Helicity does become quite strong with favorable values for rotating updrafts with incoming storms. LCL heights lower overnight as well. Models show a 850mb jet of 40-50kts overnight. Given these parameters, isolated tornadoes are a concern with the main threat being damaging winds up to 60 mph and hail of 0.5 to 1 inch. SPC has placed essentially the entire area under a slight risk of severe thundestorms, even though the western/southern half of the area seems to have the greatest threat. Link to comment Share on other sites More sharing options...
jaxjagman Posted March 30, 2017 Author Share Posted March 30, 2017 Short range models keep backing off instabilities.Not as impressive looking as it once was. Link to comment Share on other sites More sharing options...
Wmsptwx Posted March 30, 2017 Share Posted March 30, 2017 Boy, this week sure fell apart in a hurry. Link to comment Share on other sites More sharing options...
Witness Protection Program Posted March 30, 2017 Share Posted March 30, 2017 So the line of storms is 90 miles to the west near Jackson, but there's a bank branch here that's already closed with a sign about 'Severe weather threat.' Somebody just wanted to beat the traffic. Link to comment Share on other sites More sharing options...
EastKnox Posted March 31, 2017 Share Posted March 31, 2017 Why is the NAM so amped lately only to back off at the last minute? It did this for winter and now for this severe threat. Link to comment Share on other sites More sharing options...
nrgjeff Posted March 31, 2017 Share Posted March 31, 2017 They 'upgraded' the NAM a few weeks ago. It also has some strange temperature biases. Thankfully MOS is not really impacted. Link to comment Share on other sites More sharing options...
PowellVolz Posted April 4, 2017 Share Posted April 4, 2017 Looking rough tomorrow across the south Sent from my iPhone using Tapatalk Link to comment Share on other sites More sharing options...
nrgjeff Posted April 4, 2017 Share Posted April 4, 2017 Wednesday 4/5 should be a stronger version of Monday, but I'm not sold on a big outbreak. I figure Georgia gets the most concentrated severe. Tennessee has to recover from morning rain. The outflow boundary from that morning rain should remain in Georgia, due to ongoing rain in Georgia. This deep of a low one has to consider the warm front up in the Ohio Valley. Northern wave wind fields will be less influenced by Southern stuff, with low level backing up on the Ohio River. Will leave it to the Ohio Valley sub-forum. North Alabama might be the most interesting spot in our sub-forum. Georgia outflow should extend back to the hybrid cold front in Alabama. Atmo has more time to recover in Alabama as the morning rain pushes east. Challenge will be recovering the low level jet just-in-time after the morning migration into Georgia. North Bama low level wind fields are forecast to respond to the next short-wave, but it could be too late for much severe. I'm even more skeptical in Tenn. Still just early April. Weekly charts righted themselves overnight for the second half of April. Trough west with SER is back for late April. Link to comment Share on other sites More sharing options...
Mrwolf1972 Posted April 5, 2017 Share Posted April 5, 2017 Ain't seeing any morning rain just clear skyskies but look at these maps from the name 3k looks bad for valley and plateau name also shows early rain stays south and east Link to comment Share on other sites More sharing options...
Mrwolf1972 Posted April 5, 2017 Share Posted April 5, 2017 Hrr looks mean on 8z Link to comment Share on other sites More sharing options...
PowellVolz Posted April 5, 2017 Share Posted April 5, 2017 Morning convection looks to stay SE of E Tenn. Seemed like MRX was hoping this would chill out our area but it's not happening. Sent from my iPhone using Tapatalk Link to comment Share on other sites More sharing options...
JayCee Posted April 5, 2017 Share Posted April 5, 2017 2 hours ago, PowellVolz said: Morning convection looks to stay SE of E Tenn. Seemed like MRX was hoping this would chill out our area but it's not happening. Sent from my iPhone using Tapatalk Dense clouds are keeping it cooler here. If they remain most of the morning, it will probably keep us a bit more stable than if we had the sun out. Link to comment Share on other sites More sharing options...
PowellVolz Posted April 5, 2017 Share Posted April 5, 2017 Dense clouds are keeping it cooler here. If they remain most of the morning, it will probably keep us a bit more stable than if we had the sun out. If the warm front goes through it won't matter imo. Sent from my iPhone using Tapatalk Link to comment Share on other sites More sharing options...
janetjanet998 Posted April 5, 2017 Share Posted April 5, 2017 SPC mentioned something about moisture being underdone in the SE.... that may mean more moisture to work with later up north too Link to comment Share on other sites More sharing options...
nrgjeff Posted April 5, 2017 Share Posted April 5, 2017 Agree it applies into Tenn. HRRR seems too dry. Georgia outflow looks to curl up through Alabama and maybe into southeast Tenn. Temps heating up and dews advecting in. I've converted from CINH. If that outflow maintains locally higher helecity, I'm a believer. Link to comment Share on other sites More sharing options...
JayCee Posted April 5, 2017 Share Posted April 5, 2017 Looking worrisome per MRX--especially over southern areas: Quote National Weather Service Morristown TN 1116 AM EDT Wed Apr 5 2017 .DISCUSSION...A very active day is in store with a strong upper level trough of low pressure moving from Missouri/Arkansas toward the lower Ohio Valley. Satellite shows a double jet structure across the Tennessee/Mississippi Valleys which will enhance the lift over the Region Today into the this evening. The strong jet forcing will enhance the fronto-genetic forcing across middle Tennessee Alabama by mid/late afternoon. Ahead of this activity, a warm frontal boundary is moving slowly north across northeast Alabama/northern Georgia. Models are doing a poor job in analysing this activity thus confidence with this convection is low. However, as pressure falls increase ahead of the strong upper trough over the Tennessee Valley this boundary will likely move slowly northward. This boundary may enhance the tornado threat across southeast Tennessee/southwest North Carolina later Today. Giving increasing shear and instability later today along with synoptic forcing, threat for severe storms will increase. Strong potential long-track tornadoes are possible, especially over the southern Plateau and southeast Tennessee given the warm frontal boundary. Besides the tornado threat, strong winds aloft, lowering freezing level, and increasing HAIL CAPES will likely produce some damaging winds and large hail up to Golfball size. Link to comment Share on other sites More sharing options...
JayCee Posted April 5, 2017 Share Posted April 5, 2017 45 minutes ago, PowellVolz said: If the warm front goes through it won't matter imo. Sent from my iPhone using Tapatalk It appears the clouds are rapidly clearing out now, so I'd say we're in for a rocky afternoon & evening. Hope everyone stays safe out there! Link to comment Share on other sites More sharing options...
John1122 Posted April 5, 2017 Share Posted April 5, 2017 It's been off and on sun here, it's up to 70 degrees now. Around 10 degrees warmer than areas to the S and East of me. I think we'll probably all see low to mid 70s this afternoon except maybe far eastern areas where the rain is moving through. Link to comment Share on other sites More sharing options...
jaxjagman Posted April 5, 2017 Author Share Posted April 5, 2017 Mesoscale Discussion 0442 NWS Storm Prediction Center Norman OK 0102 PM CDT Wed Apr 05 2017 Areas affected...Portions of central KY...middle TN...northern/central AL...extreme northwest GA Concerning...Severe potential...Tornado Watch likely Valid 051802Z - 052030Z Probability of Watch Issuance...95 percent SUMMARY...The risk for significantly severe storms capable of producing very large hail and tornadoes, along with damaging winds, is expected to increase around and after 19Z. The issuance of a Tornado Watch is expected soon. DISCUSSION...Northward return of modest moisture continues in the open warm sector of a deep cyclone -- from parts of the TN Valley region northward to the lower and middle Ohio Valley region. The leading edge of towering cumulus fields is noted from far northwest AL into western parts of middle TN and western KY, near a pre-frontal confluence axis trailing south-southeast of deep low pressure over eastern MO. Despite the modest moisture, with surface dewpoints in the 50s to the lower 60s (highest south), moderately steep midlevel lapse rates around 7.5 C/km will support 500-1500 J/kg of MLCAPE. Weak capping and strengthening deep ascent ahead of an approaching midlevel trough will allow convection to gradually increase in the vicinity of the confluence axis. This activity will mature as it moves off the confluence axis and into the destabilizing warm sector -- aided by an appreciable orthogonal component of deep flow relative to the confluence axis. Strong deep shear and the aforementioned midlevel lapse rates, encouraging enhanced storm-scale upward accelerations, will support discrete and semi-discrete cells capable of very large hail. Also, the isallobaric response to the deepening surface low to the north will maintain backed surface winds (pressure falls of 2-4 mb per 2 hours) across the open warm sector, resulting in long/curved hodographs in the low levels. Tornadoes are expected, and significant tornadoes will be possible -- especially as supercells mature within a corridor from central KY to central/northern AL later this afternoon into the evening. Damaging wind gusts are also expected. ..Cohen/Hart.. 04/05/2017 ATTN...WFO...MRX...JKL...FFC...LMK...OHX...BMX...HUN...PAH... Link to comment Share on other sites More sharing options...
John1122 Posted April 5, 2017 Share Posted April 5, 2017 Full sun now and the temp is up to 74. DP is approaching 60. Link to comment Share on other sites More sharing options...
weathertree4u Posted April 5, 2017 Share Posted April 5, 2017 2 minutes ago, John1122 said: Full sun now and the temp is up to 74. DP is approaching 60. Nearly 80 here with the DP approaching 60 as well.... Link to comment Share on other sites More sharing options...
Windspeed Posted April 5, 2017 Share Posted April 5, 2017 KTRI is overcast and cloudy but we've obviously had no precip. 69° with a dewpoint of 53°. The temperature has been steadily climbing however since mid-morning. If this cloudcover moves out by 4pm, even if just for an hour or two, that could be significant for late evening.I don't expect supercells from the plateau down to Northern Alabama to remain tornadic by the time they reach KTRI later tonight. But they may become linear before reaching us and we may experience some strong straight-line winds and hail. KTYS may be west enough to get in on the tornado threat, however. Link to comment Share on other sites More sharing options...
JayCee Posted April 5, 2017 Share Posted April 5, 2017 Last hour TYS reported a dewpoint of 52. Dewpoints seem depressed further to the east, but moisture is surging north through the Great Valley. Link to comment Share on other sites More sharing options...
PowellVolz Posted April 5, 2017 Share Posted April 5, 2017 Last hour TYS reported a dewpoint of 52. Dewpoints seem depressed further to the east, but moisture is surging north through the Great Valley. Temp of 74 and DP of 60 at my house north of Knoxville Sent from my iPhone using Tapatalk Link to comment Share on other sites More sharing options...
PowellVolz Posted April 5, 2017 Share Posted April 5, 2017 73 degrees, DP at 62 in Fairfield Glades. Sent from my iPhone using Tapatalk Link to comment Share on other sites More sharing options...
JayCee Posted April 5, 2017 Share Posted April 5, 2017 3 minutes ago, PowellVolz said: Temp of 74 and DP of 60 at my house north of Knoxville Sent from my iPhone using Tapatalk Most personal weather stations further to the east of Knoxville have dewpoints in the low to mid-50's, currently. I guess the system this morning has something to do with that--dry air in the wake of it. I assume they'll be on the rise quickly, however. Link to comment Share on other sites More sharing options...
jaxjagman Posted April 5, 2017 Author Share Posted April 5, 2017 URGENT - IMMEDIATE BROADCAST REQUESTED Tornado Watch Number 127 NWS Storm Prediction Center Norman OK 150 PM CDT Wed Apr 5 2017 The NWS Storm Prediction Center has issued a * Tornado Watch for portions of Northern and East-Central Alabama Northwest Georgia Southeast Indiana Central Kentucky Middle Tennessee * Effective this Wednesday afternoon and evening from 150 PM until 900 PM CDT. * Primary threats include... A few tornadoes likely with a couple intense tornadoes possible Widespread large hail likely with isolated very large hail events to 2.5 inches in diameter possible Widespread damaging wind gusts to 70 mph likely SUMMARY...Thunderstorms will form along a cold front moving across the watch area this afternoon, with some storms becoming supercells. Tornadoes, large hail, and damaging winds will become a concern through the afternoon and early evening. The tornado watch area is approximately along and 75 statute miles east and west of a line from 40 miles northeast of Louisville KY to 10 miles south southeast of Selma AL. For a complete depiction of the watch see the associated watch outline update (WOUS64 KWNS WOU7). Link to comment Share on other sites More sharing options...
nrgjeff Posted April 5, 2017 Share Posted April 5, 2017 String of pearls should be going shortly along or just east of I-65. The big question is will they rotate? Winds are trying to back from northeast Alabama into East Tenn. However cool pool of air remains in northwest Georgia; and, it could contaminate inflow for southeast Tenn. Still believe outflow and main front are intersecting in the middle of the Alabama/Tennessee border. Unfortunately the intersection will move east across horrendous terrain. Despite being smack in the middle of a daytime MDT and with a 70/50 TOR watch in effect, no chase is planned. Link to comment Share on other sites More sharing options...
Mrwolf1972 Posted April 5, 2017 Share Posted April 5, 2017 it looks like the central and eastern valley will be missed by anything worth talking about even tho we didn't have any rain this am you would think with the higher dp and temps we would but we strike out again according to the hrr and nam models they are not giving us anything anymore but showers. Link to comment Share on other sites More sharing options...
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