Eskimo Joe Posted June 16, 2021 Share Posted June 16, 2021 Too early to get interested in Fri/Sat. Without nuclear grade heat and an EML, it's going to be tough to get any MCS across the mountains. Debris clouds could spoil us Saturday...shocker. Link to comment Share on other sites More sharing options...
George BM Posted June 16, 2021 Share Posted June 16, 2021 1 hour ago, Eskimo Joe said: Too early to get interested in Fri/Sat. Without nuclear grade heat and an EML, it's going to be tough to get any MCS across the mountains. Debris clouds could spoil us Saturday...shocker. Venting section: It's early indeed and no two systems are the exact same. But I literally (Yeah... I said 'literally'. Don't cringe too hard.) was just thinking about the bolded statement and how it's these kind of potential events that are NOTORIOUS for screwing us over with early day cloud cover and/or convection that takes too long to clear out. (Think a 6z day 1 ENH+ for the region that becomes a 1630z or 20z Day 1 MRGL). Non-venting section: Saturday definitely looks like the kind of day that would have 'higher than normal' severe potential if we don't get those infamous morning shenanigans mentioned in the above paragraph ruining steeper than normal MLLRs/EML given the likely swift deep-layer flow. As always... fingers crossed. Link to comment Share on other sites More sharing options...
Kmlwx Posted June 16, 2021 Author Share Posted June 16, 2021 The 12km NAM does show a decent amount of sunshine for Saturday morning. But the GFS says no. I agree - it's too early. I'm out mostly for now. 1 Link to comment Share on other sites More sharing options...
yoda Posted June 16, 2021 Share Posted June 16, 2021 I wasn't trying to say that it was a guarantee lol... but was intrigued that there was already mention of it in the AFD already 1 Link to comment Share on other sites More sharing options...
George BM Posted June 16, 2021 Share Posted June 16, 2021 17 minutes ago, yoda said: I wasn't trying to say that it was a guarantee lol... but was intrigued that there was already mention of it in the AFD already 1 Link to comment Share on other sites More sharing options...
Kmlwx Posted June 16, 2021 Author Share Posted June 16, 2021 31 minutes ago, yoda said: I wasn't trying to say that it was a guarantee lol... but was intrigued that there was already mention of it in the AFD already Oh I didn't think you were lol Link to comment Share on other sites More sharing options...
Kmlwx Posted June 16, 2021 Author Share Posted June 16, 2021 12z NAM (at range, of course) puts the best parameter space to our north up in PA for Saturday. Again, still early - and will be interesting to see where the target shifts around. Link to comment Share on other sites More sharing options...
mappy Posted June 16, 2021 Share Posted June 16, 2021 As long as Sunday is storm free -- lined up an outing on a boat with some friends for Fathers Day, need nice weather! Link to comment Share on other sites More sharing options...
Eskimo Joe Posted June 16, 2021 Share Posted June 16, 2021 LWX storm survey from the damage in Baltimore earlier this week: 1 1 Link to comment Share on other sites More sharing options...
yoda Posted June 16, 2021 Share Posted June 16, 2021 5 hours ago, Kmlwx said: 12z NAM (at range, of course) puts the best parameter space to our north up in PA for Saturday. Again, still early - and will be interesting to see where the target shifts around. 18z NAM soundings looks nice -- ofc at range -- in the 21z/00z time period on Saturday evening Link to comment Share on other sites More sharing options...
high risk Posted June 17, 2021 Share Posted June 17, 2021 3 hours ago, yoda said: 18z NAM soundings looks nice -- ofc at range -- in the 21z/00z time period on Saturday evening Agreed. Westerly winds at 850 always makes me a little hesitant to get heavily invested, but I'm intrigued. 1 Link to comment Share on other sites More sharing options...
yoda Posted June 17, 2021 Share Posted June 17, 2021 Quite a tasty morning AFD from LWX re severe chances SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/... High pressure moves offshore Fri with srly winds developing allowing warmer and more humid air to return into the area. Most of the day appears dry, but cloud debris from a decaying MCS over the lower OH Valley may result in increasingly cloudy skies through the day. Moisture return begins in earnest Fri night with potential for one or more MCSs to track across western PA, nrn WV, the Appalachians, and the northern half of the fcst area late Fri evening into Saturday morning. Any t-storm activity Fri night may pose some severe wx risk. Saturday`s fcst largely depends on any mesoscale features hard to pinpoint their location this far out, but moisture and instability should be more than adequate to support a severe wx threat. && .LONG TERM /SUNDAY THROUGH WEDNESDAY/... Guidance appears to have slowed down a touch with the southward progression of a cold front through the area during the second half of the weekend, laying it generally in the vicinity of the MD/PA border early Sunday. The front should nose southward to near I-64 through the day. Have included a chance of showers or a few thunderstorms as a result, but general height rises aloft and modest shear should keep the risk of stronger storms at bay. PWs also decrease with mid-level drying, so any flood threat should remain low as well. The front is expected to return northward as a warm front by Monday morning as Bermuda high pressure builds offshore, low pressure shifts northeastward across the Southeast, and strong troughing digs across the central CONUS. This large trough will result in strengthening wind fields aloft, with increasing heat and humidity between that and the high offshore bolstering instability. Most non- GFS guidance has the trough and an associated surface cold front sliding across the area Tuesday (GFS/GEFS ~24 hrs quicker). An infusion of tropical moisture gliding up from the Gulf Coast may result in a flood/flash flood threat Monday into Monday night given high moisture content and somewhat slower storm motions. By Tuesday, model consensus is for 20-45+ meter 12-hr 500 mb height falls, 1000- 2500+ J/kg CAPE, and 35-50 kt 0-6 km bulk shear. Although timing uncertainties remain and there are several moving parts to iron out between now and six days from now, it appears there may be a notable severe weather threat with this unseasonably strong trough and cold front on Tuesday. Link to comment Share on other sites More sharing options...
yoda Posted June 17, 2021 Share Posted June 17, 2021 12z NAM NEST looks pretty good for N VA into S PA late Saturday afternoon into Sat night looking at sup composite... radar looks intriguing too up north... after a supercell blows up just south of DC around 21z SAT Link to comment Share on other sites More sharing options...
yoda Posted June 17, 2021 Share Posted June 17, 2021 12z NAM sounding for DC area at 00z SUN (8pm SAT) Link to comment Share on other sites More sharing options...
csnavywx Posted June 17, 2021 Share Posted June 17, 2021 It looks like a remnant EML plume gets wrapped in ahead of that front. As long as we can get some forcing strong enough to trigger convective initiation on Sat. afternoon, there will likely be some severe and good parameter space for some evening supercells. 3 Link to comment Share on other sites More sharing options...
high risk Posted June 17, 2021 Share Posted June 17, 2021 2 hours ago, csnavywx said: It looks like a remnant EML plume gets wrapped in ahead of that front. As long as we can get some forcing strong enough to trigger convective initiation on Sat. afternoon, there will likely be some severe and good parameter space for some evening supercells. Shear and instability certainly look good for late Saturday, even if we get mucked up for a while with light showers and cloud debris in the morning from the decaying MCS. Low-level shear may even be sufficient to support a lower-end TOR threat. I'm intrigued. Could be another shot Tuesday. 4 Link to comment Share on other sites More sharing options...
WxUSAF Posted June 17, 2021 Share Posted June 17, 2021 Tuesday looks like a chance for one of those old school 200mi long eastward moving squall lines? 8 Link to comment Share on other sites More sharing options...
SnowenOutThere Posted June 17, 2021 Share Posted June 17, 2021 28 minutes ago, WxUSAF said: Tuesday looks like a chance for one of those old school 200mi long eastward moving squall lines? Derecho? Link to comment Share on other sites More sharing options...
Kmlwx Posted June 18, 2021 Author Share Posted June 18, 2021 Many of the CAMs look pretty lame for Saturday. We'll have to wait and see what the trends look like as we get close. LWX is still honking about Tuesday's potential. Link to comment Share on other sites More sharing options...
CAPE Posted June 18, 2021 Share Posted June 18, 2021 Mount Holly's take on Sat and Tues from the morning AFD- Deep layer shear will be supportive of organized severe weather with values of 35-45 kts. Meanwhile, a cold front will be approaching the region from the north and we should see some convectively enhanced vorticity maxima pass across the region from upstream convection as well. Long story short, Saturday could be active with potentially multiple rounds of convection which could last into the early overnight hours, but the details and confidence in timing of any hazards remains low. At this juncture, I believe the greatest threat with any organized storms would be damaging winds given the setup (northwest flow), but again confidence on the details is low. This setup will largely depend on how the upstream convection plays out later on today and tonight. SPC continues to highlight our entire area in a Marginal Risk of severe thunderstorms, but this may need to be upgraded to a higher risk level at a later time if and when the details on timing and placement become clearer. On Tuesday, the main trough axis and jet maxima will pivot across the area sending a strong cold front through the region from the west. Guidance seems to be quite consistent on the synoptic aspects of this system at this range (beyond the potential remnant tropical system interaction on Monday) bringing the cold front through sometime Tuesday. Expect that there will be a round of showers and thunderstorms with the potential for severe thunderstorms given that bulk shear will increase to favorable levels for organized convection. The exact timing and details on the evolution of this remains quite unclear though, and will likely be dependent on how the synoptic system and front interact (if at all) with the remnant tropical system on Monday. Link to comment Share on other sites More sharing options...
high risk Posted June 18, 2021 Share Posted June 18, 2021 2 hours ago, Kmlwx said: Many of the CAMs look pretty lame for Saturday. We'll have to wait and see what the trends look like as we get close. LWX is still honking about Tuesday's potential. Yeah, Saturday's threat has lessened, but I'm not sure it's dead. I was worried about the two MCS events coming in from the Midwest would keep us cloudy and cool Saturday, but most of the CAMs heat us up pretty good regardless. The problem in the HRRR is that it destroys the moisture over us - the HRRR tends to overmix, so I'm somewhat inclined to toss. The NAM nest has a much better environment over us later Saturday, but the forcing arrives too late. I agree for now with SPC that there are too many potential negatives to go with more than a MRGL, but the chances of a decent event here aren't dead. Link to comment Share on other sites More sharing options...
Kmlwx Posted June 18, 2021 Author Share Posted June 18, 2021 18 minutes ago, high risk said: Yeah, Saturday's threat has lessened, but I'm not sure it's dead. I was worried about the two MCS events coming in from the Midwest would keep us cloudy and cool Saturday, but most of the CAMs heat us up pretty good regardless. The problem in the HRRR is that it destroys the moisture over us - the HRRR tends to overmix, so I'm somewhat inclined to toss. The NAM nest has a much better environment over us later Saturday, but the forcing arrives too late. I agree for now with SPC that there are too many potential negatives to go with more than a MRGL, but the chances of a decent event here aren't dead. That is the absolute story of our severe chances here in the Mid-Atlantic - I'm obviously still watching...but think it's more of just with a one toe in for right now. Tuesday is wayyyy too far out to do any higher end analysis on at this point. The superstitious part of me is happy we are still only at a marginal for tomorrow - we do better when SPC increases last minute lol 1 Link to comment Share on other sites More sharing options...
Kmlwx Posted June 18, 2021 Author Share Posted June 18, 2021 The 12z GFS has a really nice looking cluster coming through tomorrow around peak heating. It's tough to evaluate how exactly it goes down with the 3 or 6 hour panels. It seems to be on its own right now - would love to see that trend similarly on the CAMs - most look snoozy for now. Link to comment Share on other sites More sharing options...
csnavywx Posted June 18, 2021 Share Posted June 18, 2021 1 hour ago, Kmlwx said: The 12z GFS has a really nice looking cluster coming through tomorrow around peak heating. It's tough to evaluate how exactly it goes down with the 3 or 6 hour panels. It seems to be on its own right now - would love to see that trend similarly on the CAMs - most look snoozy for now. It appears to be a continuation of an overnight MCS that gets going over IA/IL tonight. HRDPS has it too (and the 12km NAM to a lesser extent). It's a possible scenario. HIgh bust potential tonight, though, especially with effectively 3 convective complexes (including the decaying one over OH right now) "in the way" before we get there. 1 Link to comment Share on other sites More sharing options...
Stormfly Posted June 18, 2021 Share Posted June 18, 2021 Mid Atlantic is king of the bust. 1 Link to comment Share on other sites More sharing options...
csnavywx Posted June 19, 2021 Share Posted June 19, 2021 New MCS is up and going over OH and IN. Initiation likely in the next few hours over IA. HRRR really pressing this (in the form of an MCV or remnants) as a viable trigger for tomorrow. It looks like the current MCS may track far enough south to prevent it interfering with insolation too much tomorrow morning. 1 Link to comment Share on other sites More sharing options...
Kmlwx Posted June 19, 2021 Author Share Posted June 19, 2021 4 minutes ago, csnavywx said: New MCS is up and going over OH and IN. Initiation likely in the next few hours over IA. HRRR really pressing this (in the form of an MCV or remnants) as a viable trigger for tomorrow. It looks like the current MCS may track far enough south to prevent it interfering with insolation too much tomorrow morning. Will be interesting to see if the HRRR is out to lunch or onto something. 00z NAM will be interesting to see as well to see if it aligns with those thoughts at all. Link to comment Share on other sites More sharing options...
high risk Posted June 19, 2021 Share Posted June 19, 2021 2 hours ago, Kmlwx said: Will be interesting to see if the HRRR is out to lunch or onto something. 00z NAM will be interesting to see as well to see if it aligns with those thoughts at all. The HRRR has the most aggressive solution among the CAMs, but there seems to be some consensus overall for a convectively-induced shortwave (of some intensity) to approach the area tomorrow during peak heating and generate at least scattered convection. The HRRR solution would certainly be worthy of a SLGT. 1 Link to comment Share on other sites More sharing options...
csnavywx Posted June 19, 2021 Share Posted June 19, 2021 So far, so good. That mass of convection will probably produce a coherent MCV for the region later on today. SPC keeping an eye out as well: Quote Another likely influential thunderstorm complex will be ongoing at the start of the period across southern IN/OH. In all likelihood one or more MCVs will evolve from this activity. These storm-induced eddies will likely contribute to further thunderstorm development downstream later in the day. Too much uncertainty exists regarding these yet-to-develop features to warrant more than low severe probabilities. 3 Link to comment Share on other sites More sharing options...
WxUSAF Posted June 19, 2021 Share Posted June 19, 2021 SPC bumped us to slight risk? 2 Link to comment Share on other sites More sharing options...
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