yoda Posted March 30, 2023 Share Posted March 30, 2023 15% tor contour added for NW IL and E IA on 1730z SPC OTLK Small 30% hail contour added as well in E IA 1 Link to comment Share on other sites More sharing options...
sbnwx85 Posted March 30, 2023 Share Posted March 30, 2023 1 2 Link to comment Share on other sites More sharing options...
sbnwx85 Posted March 30, 2023 Share Posted March 30, 2023 I had written this one off as nothing more than a windbag this far east into Indiana but the 12z suite has me thinking there's a pretty decent chance of a spin-up or two in the area. Link to comment Share on other sites More sharing options...
yoda Posted March 30, 2023 Share Posted March 30, 2023 SPC AC 301732 Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1232 PM CDT Thu Mar 30 2023 Valid 311200Z - 011200Z ...THERE IS A MODERATE RISK OF SEVERE THUNDERSTORMS ACROSS EASTERN IOWA INTO NORTHWEST ILLINOIS AND FAR NORTHEAST MISSOURI...AND ALSO ACROSS NORTHEAST ARKANSAS...THE MISSOURI BOOTHEEL...EXTREME WESTERN KENTUCKY...WESTERN TENNESSEE...AND FAR NORTHWEST MISSISSIPPI... ...SUMMARY... Intense and widespread severe thunderstorms are expected Friday afternoon into the overnight hours across portions of the Middle Mississippi Valley and Mid-South vicinity, eastward to the Lower Ohio and Tennessee Valleys. Intense, damaging gusts and several tornadoes (some strong and long-track) are expected. ...A regional outbreak of severe storms is expected on Friday across parts of the Mid-Mississippi Valley and also into the Mid-South... ...Synopsis... A deep mid/upper-level trough and attendant 100 kt midlevel jet will move quickly eastward from the central Plains into parts of the MS Valley and Midwest on Friday. A surface low will deepen as it moves across IA toward the Great Lakes region, as a cold front sweeps eastward through parts of the Great Plains into the mid-MS Valley. In advance of the cold front, low-level moisture will stream northward across a broad warm sector from the ArkLaTex region into parts of the lower/mid MS Valley and Midwest. ...Mid-MS Valley vicinity into IN/lower MI... Rapid destabilization and increasing large-scale ascent will support thunderstorm development by early/mid afternoon across parts of IA into northern MO. Very strong deep-layer shear (effective shear in excess of 60 kt) and MLCAPE increasing to 1000-1500 J/kg (locally greater) will support organized convection, with initial supercell development expected somewhere over central IA into north-central MO. Very large hail will be the initial threat, given steep midlevel lapse rates and cold temperatures aloft. Some uncertainty remains regarding the convective mode evolution with time, but a few semi-discrete supercells are expected to move into an environment with stronger low-level shear/SRH across eastern IA into northwest IL by late afternoon, posing a threat for a couple strong tornadoes. Evolution into small clusters or bowing segments is expected, resulting in an increasing threat of severe/damaging winds in addition to a continued threat of a few tornadoes and sporadic hail. Organized convection will spread eastward into parts of IN/southern MI Friday night. Instability will weaken with eastward extent, but some threat for damaging wind and a couple of tornadoes will persist before a more definitive weakening trend occurs overnight into early Saturday morning. ...ArkLaTex/Mid South vicinity into the TN/lower OH Valleys... A concerning scenario still appears possible across portions of the MO Bootheel, northeast AR, western TN/KY and far northwest MS vicinity during the afternoon/evening. At least mid-60s F dewpoints are expected beneath modest midlevel lapse rates. This will support 1500-2000 J/kg MLCAPE amid intense vertical shear. Forecast soundings indicate 0-1 km SRH increasing to around 400 m2/s2 by early afternoon. Thunderstorms are expected to develop by early afternoon ahead of the cold front within a pre-frontal trough/low-level confluence zone. Storm motion near 50 kt with supercell wind profiles will support cells capable of significant and long-track tornadoes. With time, upscale growth into a QLCS is expected, and intense wind gusts will be possible in addition to mesovortex tornadoes. The threat for damaging gusts and a few line-embedded tornadoes will spread into parts of the TN and lower OH Valleys Friday night, with a gradual weakening trend eventually expected overnight as storms move into increasingly weak buoyancy with eastward extent. ..Dean.. 03/30/2023 1 Link to comment Share on other sites More sharing options...
mnchaserguy Posted March 30, 2023 Share Posted March 30, 2023 I want to give it a shot tomorrow but I'm having a tough time with storm motions in the 50-60 knot range. Driving 3-4 hours each way to hopefully watch a storm fly by just doesn't sound all that appealing. Throw in a snowstorm on the drive home and it really doesn't sound like it's worth it coming from MSP. 1 Link to comment Share on other sites More sharing options...
andyhb Posted March 30, 2023 Share Posted March 30, 2023 When the 3 km NAM comes in looking like the hyped up runs of the FV3/HRRR, you might have a problem. 18z run is crazy for the northern MDT/vicinity. 1 Link to comment Share on other sites More sharing options...
SchaumburgStormer Posted March 30, 2023 Share Posted March 30, 2023 1 minute ago, andyhb said: When the 3 km NAM comes in looking like the hyped up runs of the FV3/HRRR, you might have a problem. 18z run is crazy for the northern MDT/vicinity. Just your everyday string of supercells plowing through IA/IL 2 Link to comment Share on other sites More sharing options...
sbnwx85 Posted March 30, 2023 Share Posted March 30, 2023 18 minutes ago, SchaumburgStormer said: Just your everyday string of supercells plowing through IA/IL Look at that little guy roaming through St. Joseph County! Link to comment Share on other sites More sharing options...
CheeselandSkies Posted March 30, 2023 Share Posted March 30, 2023 @SchaumburgStormer Gotta include the one with updraft helicity for full geddon effect. Link to comment Share on other sites More sharing options...
Kaner88 Posted March 30, 2023 Share Posted March 30, 2023 Just don't feel good about the potential for north-central / northeast Illinois. Taking models verbatim, we have potentially widespread, potentially strong storms plowing through the area in the morning hours, almost totally overcast skies through the balance of the day, and yet somehow we still end up with over 1000 j/kg CAPE? I get the very impressive dynamics of the system, including similarly-impressive unstable air advection on northwards, but a daytime high in the area somewhere in the low/mid-60s with extensive cloud cover and substantial early-morning convection never feels very good. Assuming model guidance is right and I'm dead-wrong (more likely than not), though, I'm super concerned about damaging winds in the Chicagoland area. Storm movement per LOT potentially over 60 MPH plus the aforementioned dynamics of this system lead to some eye-watering images like this ... maximum 4-hour swath 10m winds showing pretty large swaths of >80 knot (~92 MPH) winds with this line. Pretty much a worst-case scenario type of graphic, of course, but does give a sense of what mets & others here have discussed re: significant severe potential. Link to comment Share on other sites More sharing options...
andyhb Posted March 30, 2023 Share Posted March 30, 2023 8 minutes ago, Kaner88 said: Just don't feel good about the potential for north-central / northeast Illinois. Taking models verbatim, we have potentially widespread, potentially strong storms plowing through the area in the morning hours, almost totally overcast skies through the balance of the day, and yet somehow we still end up with over 1000 j/kg CAPE? I get the very impressive dynamics of the system, including similarly-impressive unstable air advection on northwards, but a daytime high in the area somewhere in the low/mid-60s with extensive cloud cover and substantial early-morning convection never feels very good. Assuming model guidance is right and I'm dead-wrong (more likely than not), though, I'm super concerned about damaging winds in the Chicagoland area. Storm movement per LOT potentially over 60 MPH plus the aforementioned dynamics of this system lead to some eye-watering images like this ... maximum 4-hour swath 10m winds showing pretty large swaths of >80 knot (~92 MPH) winds with this line. Pretty much a worst-case scenario type of graphic, of course, but does give a sense of what mets & others here have discussed re: significant severe potential. Northeast IL/Chicagoland sure, north-central IL is definitely in a fairly high threat area though. Link to comment Share on other sites More sharing options...
MNstorms Posted March 30, 2023 Share Posted March 30, 2023 uh, are we restricting this strictly to severe thunderstorms? Minnesota and Wisconsin may receive anywhere from 0-15'' on the back side (could bust). All in 6-8 hours with thundersnow likely. 2 Link to comment Share on other sites More sharing options...
King James Posted March 30, 2023 Share Posted March 30, 2023 I personally am prepared for a rainy night, drizzle until about 4pm tomorrow, clouds clear and sun comes out, day turns beautiful and I watch some storms to my southeast. A tradition unlike any other 1 Link to comment Share on other sites More sharing options...
CheeselandSkies Posted March 30, 2023 Share Posted March 30, 2023 What a way for MKX to start their afternoon AFD... Quote Tonight through Saturday: Very interesting (and potentially dangerous) weather ahead of us tonight through Saturday as we go from winter to summer and back to winter in a very short time span. (Long Discussion Ahead) 3 Link to comment Share on other sites More sharing options...
SchaumburgStormer Posted March 30, 2023 Share Posted March 30, 2023 36 minutes ago, CheeselandSkies said: What a way for MKX to start their afternoon AFD... LOT pounding it too. Concern for several tornadoes into the area, including a noted risk for significant/long- track tornadoes, continues to increase with the latest forecast guidance. This guidance puts the low-level wind/thermo tornado parameter space into the upper-echelon climatology of values for our area, highlighted by significant 0-1km EHI and 0-3km CAPE that will be realized by discrete supercells. At this point, the highest threat area for tornadoes appears to be near/west of I-39. However, the eastward extent of the highest supercell/tornado risk will be determined by how quickly convection evolves toward a linear mode. 3 Link to comment Share on other sites More sharing options...
Stebo Posted March 31, 2023 Share Posted March 31, 2023 I am absolutely getting concerned about Chicago Metro on this one. Models have supercells all around and some have them moving into the suburbs around 22-02z. Link to comment Share on other sites More sharing options...
Thundersnow12 Posted March 31, 2023 Share Posted March 31, 2023 1 hour ago, MNstorms said: uh, are we restricting this strictly to severe thunderstorms? Minnesota and Wisconsin may receive anywhere from 0-15'' on the back side (could bust). All in 6-8 hours with thundersnow likely. The real winners of this system 1 Link to comment Share on other sites More sharing options...
canderson Posted March 31, 2023 Share Posted March 31, 2023 44 minutes ago, Stebo said: I am absolutely getting concerned about Chicago Metro on this one. Models have supercells all around and some have them moving into the suburbs around 22-02z. I don’t chase … but if I did I’d sit myself near the 57 and 294 interchange. Looks primed for fireworks. 1 Link to comment Share on other sites More sharing options...
WxSynopsisDavid Posted March 31, 2023 Share Posted March 31, 2023 2 hours ago, Kaner88 said: Just don't feel good about the potential for north-central / northeast Illinois. Taking models verbatim, we have potentially widespread, potentially strong storms plowing through the area in the morning hours, almost totally overcast skies through the balance of the day, and yet somehow we still end up with over 1000 j/kg CAPE? I get the very impressive dynamics of the system, including similarly-impressive unstable air advection on northwards, but a daytime high in the area somewhere in the low/mid-60s with extensive cloud cover and substantial early-morning convection never feels very good. Assuming model guidance is right and I'm dead-wrong (more likely than not), though, I'm super concerned about damaging winds in the Chicagoland area. Storm movement per LOT potentially over 60 MPH plus the aforementioned dynamics of this system lead to some eye-watering images like this ... maximum 4-hour swath 10m winds showing pretty large swaths of >80 knot (~92 MPH) winds with this line. Pretty much a worst-case scenario type of graphic, of course, but does give a sense of what mets & others here have discussed re: significant severe potential. Dynamics can compensate for lack of instability (high shear/low cape outbreaks). In fact some of the higher end, more substantial outbreaks have featured such setups. Though I live in the Midatlantic (Virginia), I can testify that overcast and 60f temp means very little in the way of hindering the setup. I chased the 2/24/16 outbreak here in VA. There was an overcast all day and temps were bouncing between 50-70 all day. 2 devastating high-end EF3’s struck Appomattox and Essex. Also, our state record tornado that struck Petersburg on 8/6/93 was a high-end F4. That day also featured an overcast and thick cloud deck. 2 Link to comment Share on other sites More sharing options...
Radtechwxman Posted March 31, 2023 Share Posted March 31, 2023 23z hrrr showing an mcs developing in ne MO at end of its run. Oh boy. Getting 3-28-20 vibes from that run. Hopefully won't get an early day wave that messes everything up. 1 1 Link to comment Share on other sites More sharing options...
Indystorm Posted March 31, 2023 Share Posted March 31, 2023 1 hour ago, Stebo said: I am absolutely getting concerned about Chicago Metro on this one. Models have supercells all around and some have them moving into the suburbs around 22-02z. Since I live in Griffith I will be monitoring this board and warnings all day Friday and am somewhat nervous hearing your concern Fortunately I live in a basement apartment. 1 Link to comment Share on other sites More sharing options...
Stebo Posted March 31, 2023 Share Posted March 31, 2023 40 minutes ago, StormChaser4Life said: 23z hrrr showing an mcs developing in ne MO at end of its run. Oh boy. Getting 3-28-20 vibes from that run. Hopefully won't get an early day wave that messes everything up. Its a bit soon to jump on this concern especially since no other model has it yet. If we see some consistency there would be concern of that screwing with the setup. Link to comment Share on other sites More sharing options...
CheeselandSkies Posted March 31, 2023 Share Posted March 31, 2023 41 minutes ago, StormChaser4Life said: 23z hrrr showing an mcs developing in ne MO at end of its run. Oh boy. Getting 3-28-20 vibes from that run. Hopefully won't get an early day wave that messes everything up. 00Z has it too, but it then turns it into round 1 of potential supercells across IL, and fires another round behind that. Iowa looks a lot less impressive (at least purely in terms of simulated discrete convection with strong UH) this run compared to previous ones, though. Link to comment Share on other sites More sharing options...
pen_artist Posted March 31, 2023 Author Share Posted March 31, 2023 00z HRRR showing pretty quick recovery after first round of cells move through C IL. Has a 2nd round of more intense moving through the heart of the metro between 6-9pm. Link to comment Share on other sites More sharing options...
Malacka11 Posted March 31, 2023 Share Posted March 31, 2023 NAM has the earlier MCS now too. Link to comment Share on other sites More sharing options...
Radtechwxman Posted March 31, 2023 Share Posted March 31, 2023 Other model guidance suggesting an early wave now. 01z hrrr has an expansive precip shield at end of its run. Definitely something that will need to be watched. Certainly would shunt the threat south where destabilization could possibly happen on southern fringe. This is just giving me 3-28-20 vibes. This is about the time models went from outbreak scenario to a total mess. Only time will tell. 1 1 Link to comment Share on other sites More sharing options...
Chinook Posted March 31, 2023 Share Posted March 31, 2023 I wonder if we will have a significant tornado get going in western Illinois as per the 03z HRRR updraft helicity (hour 17-18) Link to comment Share on other sites More sharing options...
Radtechwxman Posted March 31, 2023 Share Posted March 31, 2023 15 minutes ago, Chinook said: I wonder if we will have a significant tornado get going in western Illinois as per the 03z HRRR updraft helicity (hour 17-18) That early day wave definitely bears watching. Cape, moisture, and sigtor all building in with it. Link to comment Share on other sites More sharing options...
yoda Posted March 31, 2023 Share Posted March 31, 2023 I think that is the largest hatched area I have ever seen for TOR probs on the new Day 1 1 Link to comment Share on other sites More sharing options...
cheese007 Posted March 31, 2023 Share Posted March 31, 2023 12 minutes ago, yoda said: I think that is the largest hatched area I have ever seen for TOR probs on the new Day 1 14 million people in that hatched zone Link to comment Share on other sites More sharing options...
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