Jim Martin Posted March 5, 2017 Share Posted March 5, 2017 Enhanced risk for severe thunderstorms tomorrow in Southwest Missouri and Northwest Arkansas. The Storm Prediction Center has indicated that all severe hazards are possible. Link to comment Share on other sites More sharing options...
jojo762 Posted March 5, 2017 Share Posted March 5, 2017 Not too surprised to see an ENH risk. Wind fields look pretty good and models have trended upward with instability. Any discrete supercell that were to form would have a pretty solid shot at producing tornadoes across much of the threat area, but especially SE KS/NE OK/SW MO/NW AR. Link to comment Share on other sites More sharing options...
Weatherdemon Posted March 6, 2017 Share Posted March 6, 2017 Some pretty solid forecast soundings ahead of the line of forecasted convection in NE-EC Central OK on the last several NAM runs. My team may go out pending tomorrows model runs. Link to comment Share on other sites More sharing options...
WhiteoutWX Posted March 6, 2017 Share Posted March 6, 2017 3 hours ago, Weatherdemon said: Some pretty solid forecast soundings ahead of the line of forecasted convection in NE-EC Central OK on the last several NAM runs. My team may go out pending tomorrows model runs. Looks rather capped before cold front sweeps through, no? Link to comment Share on other sites More sharing options...
jojo762 Posted March 6, 2017 Share Posted March 6, 2017 00Z 4K NAM is very volatile across a large area tomorrow evening, to say the least... especially in SE KS. Notable that it pops discrete supercells along this entire corridor. 4NAM/12NAM/GFS all depict an impressive parameter space at 00Z in E/SE KS tomorrow generally showing an uncapped environment juxtaposed to low 60s DPs, 200-300 m2/s2 0-1KM SRH, 1500-2500 J/, KG MLCAPE, SFC-6KM shear of 50-60kts, and impressive low-level CAPE as well. In my opinion I would not be surprised to see the SPC highlight this area with a 10% TOR risk at some point tomorrow. Any storms that initiate in this area will likely stay discrete owing to only subtle/glancing forcing. A little concerned by potential backing of mid-level winds, but we will have to see how that evolves on VWPs tomorrow. Link to comment Share on other sites More sharing options...
Jonbo Posted March 6, 2017 Share Posted March 6, 2017 Potential Hazard Type: PDS Tornado? How often does that show up? Link to comment Share on other sites More sharing options...
jojo762 Posted March 6, 2017 Share Posted March 6, 2017 38 minutes ago, Jonbo said: Potential Hazard Type: PDS Tornado? How often does that show up? You can find it quite frequently when you get an impressive forecast environment like the 4K NAM has. Link to comment Share on other sites More sharing options...
jojo762 Posted March 6, 2017 Share Posted March 6, 2017 SPC went with a small 10% TOR across southern Missouri including Springfield... Broad 5% TOR encompassing southern Iowa, much of Missouri, eastern KS, and NW AR/NE OK. ENH risk for damaging winds and large hail across MO and NE OK/NW AR. ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS OVER A PORTION OF THE LOWER TO MIDDLE MISSISSIPPI VALLEY REGION... ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM A PORTION OF THE CENTRAL AND SOUTHERN PLAINS INTO THE MIDDLE TO UPPER MISSISSIPPI VALLEY... ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM A PORTION OF THE CENTRAL AND SOUTHERN PLAINS TO THE LOWER THROUGH UPPER MISSISSIPPI VALLEY... ...SUMMARY... Severe thunderstorms are expected mainly late this afternoon or evening through tonight across a part of the upper and middle Mississippi Valley to the Ozarks and Mid-South. A greater concentration of severe thunderstorms may occur across parts of northwestern Arkansas and southern Missouri Monday evening. Primary threats will be damaging wind gusts and large hail, but a few tornadoes will also be possible, especially from extreme northern Arkansas into southern Missouri. ...Synopsis... Synoptic upper trough currently from the northern Rockies to the Great Basin will continue northeast through the central and northern Plains during the day and eject negatively tilted into the upper MS Valley this evening. Surface low will deepen over the eastern Dakotas into western MN, while trailing cold front merges with the dry line as it advances through the central plains during the day and into the MS valley and southern Plains overnight. Warm front extending east from the low will move northward through the upper MS valley and Great lakes regions. ...Ozarks through the middle and Upper Mississippi Valley areas... With initial return of partially modified Gulf moisture, widespread low clouds are expected in warm sector today, limiting boundary-layer warming. The 00Z observed raob data from Sunday evening already show a warm layer associated with a remnant elevated mixed layer in place across the central Plains and middle MS Valley region. Northward advection of partially modified Gulf moisture beneath 7-7.5 C/km mid-level lapse rates will destabilize the atmosphere during the day with corridor mlcape from 1000-1500 J/kg expected to evolve from central and southern Plains into the middle to lower MS Valley. Instability will remain marginal over the upper MS valley region where moisture return will be more limited. Initial storms will likely develop over the upper MS Valley region where deeper forcing attendant to the ejecting shortwave trough will likely result in erosion of capping inversion along and just ahead of the cold front. Initial discrete storms should rapidly evolve into linear segments with damaging wind and hail the primary threats, though a brief tornado cannot be ruled out. Given the presence of capping in warm sector and tendency for the deeper forcing to move into the upper MS Valley, most of the warm sector from the central plains into the middle to lower MS valley will remain capped during the day. However, storms will likely develop along cold front by early evening as this boundary overtakes the dryline across eastern KS. Initially discrete storms will evolve into linear segments. Given very strong effective bulk shear exceeding 50 kt, organized storms are expected including supercells and bowing linear segments. Large hail and a couple tornadoes will be the main threats with initial storms. However, as activity evolves into a dominant linear mode, damaging wind will become the primary threat, though a couple of qlcs tornadoes will also be possible with any embedded mesovortices. The best chance for pre-frontal storm initiation appears to be within confluent flow regime along conveyor belt and in association with terrain features from northwestern AR into southern MO where some of the convective-allowing models initiate discrete cells. Should this occur during the early evening, large 0-1 km hodographs would support supercells with low-level mesocyclones and an attendant threat for a few tornadoes. ..Dial/Cook.. 03/06/2017 Link to comment Share on other sites More sharing options...
Quincy Posted March 6, 2017 Share Posted March 6, 2017 A very narrow window may exist for a few supercells ahead of the cold front from northeastern OK into eastern KS and northwestern MO before the storm mode becomes linear, but the greater focus for prefrontal cells should lie from AR into much of MO and perhaps even IA. The HRRR has been ramping up parameters in the narrowing warm sector of the lower Missouri Valley and even as far north as southern MN. I'd watch two areas in the warm sector: Northern MO and southern MO/northern AR. This is also a setup that could feature a rogue supercell or two in eastern OK, although CAMs have been inconsistent with initiation there. Link to comment Share on other sites More sharing options...
Santa Clause Posted March 6, 2017 Share Posted March 6, 2017 I only see 5 percent TOR in update. Very small window here, but potential is very much there. Link to comment Share on other sites More sharing options...
JMT417 Posted March 6, 2017 Share Posted March 6, 2017 1 hour ago, Wmsptwx said: I only see 5 percent TOR in update. Very small window here, but potential is very much there. It was 10 in the prior Outlook. They dialed it back Link to comment Share on other sites More sharing options...
nrgjeff Posted March 6, 2017 Share Posted March 6, 2017 Agree with Quincy above RE two areas of interest. WF lifting thru Missouri could provide a focus just east of St. Joseph and points east. Better parameters are noted in southwest/southern Missouri. CF/DL may intersect there but it's not a true triple point w/o the WF. Introduction of a differential heating boundary would make it a triple point. Parameters may be better southern MO but northwest MO is slightly better chase terrain. I know at least one member in southwest MO hates severe, so I have some good news. Agree with faster models that gets it out of SW MO earlier in the evening. Window for TOR is narrow all targets, both geographically and temporally. Looks like mainly a straight line wind deal. Chaser best shot is a break in the line. Better yet, watch some conference basketball tournaments at home. Link to comment Share on other sites More sharing options...
janetjanet998 Posted March 6, 2017 Share Posted March 6, 2017 my sleeper pick is central/ southern MN maybe near MSP too Link to comment Share on other sites More sharing options...
Santa Clause Posted March 6, 2017 Share Posted March 6, 2017 Looking at some data, today may be a sleeper as a whole. Potential is there for some solid severe. Link to comment Share on other sites More sharing options...
OUGrad05 Posted March 6, 2017 Share Posted March 6, 2017 Not sure I would have dialed back to 5% on the tor, probably would have kept 10% just made it a narrow corridor. If a couple supercells get going with the wind profiles the way they are a couple tornadoes is a real possibility. Days like today sometimes surprise folks. It doesn't seem like a day where we'll have cells popping all over the place, instead we'll probably have a few isolated cells go up ahead of the front. Without a bunch of junk convection around and decent to good wind profiles a couple of producers with EF0/EF1s wouldn't surprise me at all. Link to comment Share on other sites More sharing options...
nrgjeff Posted March 6, 2017 Share Posted March 6, 2017 Agree ^ on the 10%. SPC may be hedging since the location of the boundary is in question. Latest HRRR has a beast coming out of eastern Kansas in the west-central Missouri. That HRRR shows a true DL/CF/WF triple point feature; hence, it blows up the sup. Barring a junk rain debacle, the 10% may return. Still mainly straight winds though, for those in SW MO who hate severe. Chasers would also be happier with west-central MO thanks to roads/terrain and still well south of the KC metro sprawl. Link to comment Share on other sites More sharing options...
monsoonman1 Posted March 6, 2017 Share Posted March 6, 2017 Was going to stay close to home and hope to see some linear stuff but HRRR is making me want to head south towards Iola, KS. Going to wait until early afternoon to decide for sure but starting to think today has some potential. Winds are ripping right now. Link to comment Share on other sites More sharing options...
jojo762 Posted March 6, 2017 Share Posted March 6, 2017 14Z HRRR highlighted the potential of an isolated long-tracking supercell initiating near I-35 in KS late this afternoon and tracking northeastward into MO... impressive UH-track as well. 15Z HRRR continues this idea of an isolated discrete supercell. If that happens, things could get very interesting with that storm. Link to comment Share on other sites More sharing options...
bjc0303 Posted March 6, 2017 Share Posted March 6, 2017 HrRR seems to be initiating these cells in an area of focused pressure falls/ascent in exit region of a very subtle speed max emerging from the a rockies at about initiation time. This may get pretty interesting. Link to comment Share on other sites More sharing options...
bdgwx Posted March 6, 2017 Share Posted March 6, 2017 Yeah, if the HRRR is to be believed then the enhanced risk needs to expand/move west and have the 10% tornado risk reintroduced. Link to comment Share on other sites More sharing options...
bjc0303 Posted March 6, 2017 Share Posted March 6, 2017 Enhanced expanded into KS Link to comment Share on other sites More sharing options...
jojo762 Posted March 6, 2017 Share Posted March 6, 2017 SPC expanded the ENH westward and north. Also added back the 10% TOR with a hatched area across SE KS and SW/W MO. This 10% TOR is much larger than the previous one. Link to comment Share on other sites More sharing options...
MattPetrulli Posted March 6, 2017 Share Posted March 6, 2017 Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1033 AM CST Mon Mar 06 2017 Valid 061630Z - 071200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS MID-MS VALLEY AND OZARK PLATEAU... ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS UPPER MIDWEST TO EASTERN OK AND AR... ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS CENTRAL STATES... ...SUMMARY... Numerous severe storms are expected starting late afternoon and continuing into tonight across the central states. The greatest concentration of tornadoes, a couple of which may be strong, damaging winds, and large hail is expected to be across the Ozark Plateau to the Mid-Mississippi Valley. ...Lower Missouri Valley, Ozark Plateau, Mid-South... Scattered storms should develop along the dryline late afternoon centered on eastern KS as mid-level height falls overspread this boundary downstream of a vigorous northern Great Plains shortwave trough. Despite a weakness in hodographs near 700 mb, low and deep-layer shear will be strong. In conjunction with a destabilizing air mass characterized by a plume of returning Gulf moisture with lower 60s surface dew points amid steep mid-level lapse rates, the environment will be quite favorable for supercells. As the cold front overtakes the dryline, storms will grow upscale this evening. This should result in a multi-faceted severe risk, all of which yield probabilistic upgrades this outlook. Large hail and tornadoes, some of which may be significant, will be the primary risks with any supercells that can maintain discrete mode immediately ahead of a probable QLCS. Damaging winds and a few embedded tornadoes should be the primary hazards with a fast-moving QLCS, supported by very strong and strengthening mid-level winds, along the northern extent of moderate instability across Missouri towards the mid-Mississippi Valley.. With southwest extent towards the Red River, deep-layer winds will be oriented increasingly parallel to the front, which should tend to favor a predominant QLCS mode and a more isolated/less intense severe risk tonight. ...Upper Midwest... Strong forcing for ascent will overspread this region along the northern extent of the warm sector, yielding scattered storm development along the cold front late afternoon. Rather steep mid-level lapse rates will compensate for comparatively lesser boundary-layer moisture farther south. Elongated, straight-line hodographs should support a few supercells, although the degree of forcing will probably tend to favor upscale growth into one or more short-line segments. All hazards appear possible with widely scattered severe reports expected. Link to comment Share on other sites More sharing options...
jojo762 Posted March 6, 2017 Share Posted March 6, 2017 Was wondering if/when they were going to add mention of sig tor potential... Potential is obviously there. Link to comment Share on other sites More sharing options...
pbrussell Posted March 6, 2017 Share Posted March 6, 2017 Well, I've got my chase hat on today for obvious reasons. Will likely duck out of work early this afternoon. Link to comment Share on other sites More sharing options...
Chinook Posted March 6, 2017 Share Posted March 6, 2017 The 10% tornado contour includes 4.3 million people, with being on the edge of downtown Kansas City . Pretty big time stuff. I wonder if the SPC saw -more- evidence for numerous discrete cells with the 06z and 12z convection-allowing models. Link to comment Share on other sites More sharing options...
jojo762 Posted March 6, 2017 Share Posted March 6, 2017 Moisture is looking pretty meh this far. SFC DPs In the 55-60 range in Kansas attm. Link to comment Share on other sites More sharing options...
bjc0303 Posted March 6, 2017 Share Posted March 6, 2017 1 minute ago, jojo762 said: Moisture is looking pretty meh this far. SFC DPs In the 55-60 range in Kansas attm. Seemed like they were mixing out but it looks like they're recovering in central /west OK which may make it into KS in time. Link to comment Share on other sites More sharing options...
jojo762 Posted March 6, 2017 Share Posted March 6, 2017 Looks like some CU is starting to bubble up in NC Kansas/ SC Nebraska ahead of the 100kt H5 speed max. Most of it appears to be behind the dryline/boundary ATTM. Link to comment Share on other sites More sharing options...
jojo762 Posted March 6, 2017 Share Posted March 6, 2017 Area Forecast Discussion National Weather Service Springfield MO 1120 AM CST Mon Mar 6 2017 ...Mesoscale and 18Z Aviation Updates... .MESOSCALE DISCUSSION... Issued at 1120 AM CST Mon Mar 6 2017 No major changes to expectations for tonight at this time. Low to mid 60s dewpoints will continue to stream into the area on very gusty south winds through the rest of this afternoon into the evening hours. These dewpoints will combine with relatively cold temperatures aloft to produce a rather unstable airmass across the region. Mid level height falls will begin to overspread the area by early evening, and a cold front will begin to advance southeast into the forecast area by mid to late evening. Not unlike the severe weather event last week, there will be two distinct opportunities for severe weather this evening/tonight. The first will be with any discrete supercells that are able to form ahead of the frontal boundary during the early to mid evening hours. These would likely have the greatest severe weather potential should they form. The second wave of severe weather will be with the front itself, with initial supercells (likely just north and west of the CWA) congealing into a linear complex/QLCS as the front advances to the southeast. Straight line winds, large hail, and brief meso-vort tornadoes will all be possible with this line. At this juncture, it appears that convection will begin to develop as early as 5-6 PM just to our west, with the window for discrete supercells lasting into the mid evening hours. The front should begin to accelerate by 7-9 PM, with a line of strong/severe convection sweeping across the western half or so of the CWA between 7 and 10 PM, and the remainder of the area from 10 PM through 3-4 AM tomorrow morning. Link to comment Share on other sites More sharing options...
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