andyhb Posted March 12, 2019 Share Posted March 12, 2019 Might be a decent shot at severe weather in the subforum on Thursday looking at recent guidance as very strong wind fields (broad 55-65+ kt LLJ) and cold air aloft overspread mid-upper 50s dewpoints (perhaps low 60s further south towards the OV). Could be one of those events where you have a large amount of instability concentrated in the low levels. These types of events tend to do some dirty work in this region. 1 Link to comment Share on other sites More sharing options...
Moosey2323 Posted March 12, 2019 Share Posted March 12, 2019 I'm interested to see what the Day 3 Convective Outlook looks like. Link to comment Share on other sites More sharing options...
Stebo Posted March 12, 2019 Share Posted March 12, 2019 16 minutes ago, Moosey2323 said: I'm interested to see what the Day 3 Convective Outlook looks like. It will be a marginal at best on Day 3, they will wait as long as possible to go higher, I am sure of that. Link to comment Share on other sites More sharing options...
Hoosier Posted March 12, 2019 Author Share Posted March 12, 2019 1 hour ago, andyhb said: Might be a decent shot at severe weather in the subforum on Thursday looking at recent guidance as very strong wind fields (broad 55-65+ kt LLJ) and cold air aloft overspread mid-upper 50s dewpoints (perhaps low 60s further south towards the OV). Could be one of those events where you have a large amount of instability concentrated in the low levels. These types of events tend to do some dirty work in this region. What are your thoughts on the substantial weakening of the surface low on approach? I am thinking it may not hurt because it could result in somewhat less forcing. Link to comment Share on other sites More sharing options...
Indystorm Posted March 12, 2019 Share Posted March 12, 2019 Usual caveats of instability concerns applies this far north this early in season. I;m waiting for warmer temps and richer dew points. But ya never know. Your point on forcing is well taken. o6z NAM 3k says that Thursday afternoon and evening could be rather volatile around parts of central IL and IN. Link to comment Share on other sites More sharing options...
andyhb Posted March 12, 2019 Share Posted March 12, 2019 12 hours ago, Hoosier said: What are your thoughts on the substantial weakening of the surface low on approach? I am thinking it may not hurt because it could result in somewhat less forcing. Yeah I’m thinking the same thing, plus it’s the position that I’m paying attention to mainly since it is still a pretty strong surface low despite being filling. 1 Link to comment Share on other sites More sharing options...
bowtie` Posted March 12, 2019 Share Posted March 12, 2019 On 2/26/2019 at 2:26 PM, bowtie` said: Had a small V of sandhill cranes honking the way back north today. A sure sign that Spring is soon on the way. If that was the advance guard two weeks ago, today was the whole fam damily. Multiple upon multiple V's of sandhill cranes all circling wagons north. Book it. Link to comment Share on other sites More sharing options...
Moosey2323 Posted March 12, 2019 Share Posted March 12, 2019 GRR AFD Quote With the assumption that we mix out into the warm sector on Thursday, another low-level jet impulse ahead of the cold front may be well timed with afternoon peak heating. Surface-based thunderstorms may develop. MLCAPE around 500 J/kg, 0-1 km shear of 30 kt, and 0-3 km shear of 50 kt is possible, so any relatively robust updrafts could achieve some organization. Cells that do develop would race quickly to the northeast, and given the strong low-level wind fields in place, even weak downdrafts could result in gusts around 60 mph. The nested 3 km NAM has shown more backing of surface winds than other models, and if that verifies, it suggests some isolated tornado potential in southern Michigan with STP values climbing to around 1 or 2. Tornado or not, the greater potential will be from straight-line winds, possibly strong enough to cause power outages from falling tree limbs. SPC has placed areas south of I-96 in a marginal risk for severe winds Thursday afternoon. Link to comment Share on other sites More sharing options...
Stebo Posted March 12, 2019 Share Posted March 12, 2019 DTX Could see a lull for a few hours in the wake of the morning activity as the low level warm sector slides through SE MI. With strong low level jet in place (50 knots down to around 4kft possibly) and warm mixed layer lifting through the area, could see some strong southwesterly winds in the afternoon Thursday. Though models have been supporting higher gusts Thursday it should be noted that local probability graphics show a decreasing trend in likelihood of seeing wind gusts in excess of 40 mph. A several hour period with gusts of 30-40 mph seems reasonable at this point. Caveat to that will be if any showers can persist or afternoon redevelopment of showers mixes down the stronger winds. Strong southwesterly warm air advection will help temperatures climb into the 60s for most locations Thursday steepening low level lapse rates. CAPE values of a few hundred j/kg may aide in the development a broken line of storms moving across lower MI. Strong winds will be the primary threat with any storms or stronger showers as the low level jet will still be strong. Dry slot surging into the area overnight will help shut off the showers for most of the area overnight. IWX Focus then shifts to convective potential in warm sector Thurs afternoon as well as gusty winds outside any convection. For the gradient winds, trends continue to point towards a period of near advisory criteria as low level flow in excess of 60 knots resides not far off the surface. To complicate things, this same wind field could be tapped by low topped convection that may form during the afternoon hours with plenty of bulk shear (50 kts to as high as over 80s depending on model of choice). Keys to severe potential will be if breaks in clouds can occur and if we advect in low to maybe mid 50 dewpoints which will translate to around 500 J/KG of MUCAPE. SPC has marginal risk across the area with damaging winds the main threat. However, given the strong wind fields and shear/helicity values a non-zero threat for qlcs tornadoes exists. A lot has to come together for this and always a tough one in March, but still needs to be watched. Have kept highs upper 60s to near 70, but if breaks can occur, than MAV guidance in the mid 70s could be realized (and cause a greater severe threat). Link to comment Share on other sites More sharing options...
Stebo Posted March 13, 2019 Share Posted March 13, 2019 Hello 3km NAM Link to comment Share on other sites More sharing options...
MattPetrulli Posted March 13, 2019 Share Posted March 13, 2019 Ahhhh, that's pretty interesting. Link to comment Share on other sites More sharing options...
andyhb Posted March 13, 2019 Share Posted March 13, 2019 To further the notion, yeah those are multiple fast moving supercells there, it's not picking up on a squall line. I tend to put a lot of weight in the 500 mb setup assuming thermos are adequate in these kinds of cases. This 500 mb setup with a powerful vort lifting ENE out of a mean positive tilt long wave trough, with an elongated west-southwesterly upper level jet and the surface low position, is notorious in the Great Lakes for significant severe weather events. Link to comment Share on other sites More sharing options...
MattPetrulli Posted March 13, 2019 Share Posted March 13, 2019 CAMs also has solutions similar to 3k NAM 1 Link to comment Share on other sites More sharing options...
Indystorm Posted March 13, 2019 Share Posted March 13, 2019 Yes, I think the April 11, 1965 Palm Sunday tornadoes in IN had a positive tilt trough. Supposed to get near 70 here in IN this Thursday. Current CAMS are concerning. Link to comment Share on other sites More sharing options...
CheeselandSkies Posted March 13, 2019 Share Posted March 13, 2019 7 hours ago, Indystorm said: Yes, I think the April 11, 1965 Palm Sunday tornadoes in IN had a positive tilt trough. Supposed to get near 70 here in IN this Thursday. Current CAMS are concerning. Add the 06Z HRRR to the chorus. Has a couple strong supercells going over IN as early as 17Z tomorrow. It oversold 2/23 and last Saturday a bit (did pretty well with 3/3). I haven't really paid much attention to the HRWs before, but I might have to start. Link to comment Share on other sites More sharing options...
andyhb Posted March 17, 2019 Share Posted March 17, 2019 New seasonal forecast for AMJ from ECMWF looks active in terms of -PNA/pattern favouring cutters and severe wx. 5 Link to comment Share on other sites More sharing options...
Indystorm Posted March 17, 2019 Share Posted March 17, 2019 Well, if we get that trough in the west established there will certainly be enough moisture in the plains/midwest with current flooding situation to guarantee adequate moisture. So I don't think we have to worry too much about that variable in the coming months. And I always look forward to your scientific insights and discussions on svr wx, Andrew. Way to go! 2 Link to comment Share on other sites More sharing options...
Harry Perry Posted March 18, 2019 Share Posted March 18, 2019 Certainly looks better than last year. Link to comment Share on other sites More sharing options...
hlcater Posted March 18, 2019 Share Posted March 18, 2019 Yea I’m far more optimistic for this season over last season to say the least. Link to comment Share on other sites More sharing options...
UMB WX Posted March 18, 2019 Share Posted March 18, 2019 Sounds like another miserable April IMBY. Link to comment Share on other sites More sharing options...
Indystorm Posted March 19, 2019 Share Posted March 19, 2019 Wow does April 3 look potent for northern IL and IN on the 18z GFS. Too bad it's 384 hours. 1 Link to comment Share on other sites More sharing options...
Hoosier Posted March 19, 2019 Author Share Posted March 19, 2019 3 hours ago, Indystorm said: Wow does April 3 look potent for northern IL and IN on the 18z GFS. Too bad it's 384 hours. Maybe the first time I've replied to you with this: lol Link to comment Share on other sites More sharing options...
Indystorm Posted March 19, 2019 Share Posted March 19, 2019 4 minutes ago, Hoosier said: Maybe the first time I've replied to you with this: lol Just getting the itch for svr wx season. That EF-0 near Lowell did surprise me, though. Link to comment Share on other sites More sharing options...
Jackstraw Posted March 21, 2019 Share Posted March 21, 2019 Me too. Fantasy land is looking better for severe next weekend Link to comment Share on other sites More sharing options...
NegativeEPO Posted March 21, 2019 Share Posted March 21, 2019 Long range GFS looks absolutely miserable for pretty much everyone. That Alaskan ridge might be a permanent feature thanks to melting sea ice and warming Pacific waters. 1 Link to comment Share on other sites More sharing options...
CheeselandSkies Posted March 21, 2019 Share Posted March 21, 2019 13 minutes ago, NegativeEPO said: Long range GFS looks absolutely miserable for pretty much everyone. That Alaskan ridge might be a permanent feature thanks to melting sea ice and warming Pacific waters. ... as long as I'm not trying to drive in a kitchen sink of winter precip on April 14 like last year... Link to comment Share on other sites More sharing options...
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