weatherwiz Posted June 22 Share Posted June 22 I am just going to start off by saying WE ARE NOT LOOKING AT A WIDESPREAD, HIGH-END SEVERE WEATHER EVENT While we are lacking an elevated-mixed layer, it is important to note that EML's are important when seeking out the potential for a widespread, high-end severe weather event. You can still get severe weather and even numerous severe storms/damage but typically mostly everything falls short of high end. Now that we got that out of the way let's get into it. An elongated stationary boundary is currently positioned from off the New England coast across central New England, though the Great Lakes, and into the upper-Midwest. Shortwave energy within the north-central Plains and upper-Midwest is expected to amplify as it traverses the Great Lakes region resulting in strengthening low pressure at the sfc. This will help push the stationary boundary within New England northward as a warm front overnight and early Sunday morning. Thus, very warm and humid air advects northward. With the amplifying shortwave trough and strengthening sfc low, the response will be increasing shear across the Northeast and New England characterized by bulk shear values in the 40-50 knot range. These values are more than sufficient for convection to become organized and even acquire supercell characteristics. In addition, llvl winds are expected to back in the vicinity of the warm front, yielding enlarged hodographs and 0-1km helicity values 150-200+ m2s2 and 0-3km helicity values 200-250+ m2s2. These values are more than sufficient for the more mature thunderstorms to become supercells. Combination of temperatures rising into the 80's and dewpoints climbing into the lower 70's will yield a moderately unstable airmass characterized by mixed-layer CAP values in the 1500-200 J/KG range. Weak mid-level lapse rates, ~6 C/KM, will hold the atmosphere back from becoming more unstable. However, should dewpoint pooling occur, which is possible within the Connecticut River Valley, dewpoints could climb into the 74-76F range, this may yield a zone of mixed-layer CAP values in the 2000-2500 J/KG range and compensate a bit for the weaker lapse rates. Scattered-to-numerous thunderstorms should begin developing by early afternoon across NY/PA ahead of the cold front with thunderstorms developing across eastern NY and western New England by mid-afternoon ahead of the pre-frontal trough. Given the ingredients mentioned, the strongest thunderstorms will be capable of producing damaging wind gusts and hail. Should any discrete, mature cells develop, given the strong wind shear, the potential also exists for a few tornadoes. High PWATS should also yield potential for localized flash flooding. 4 1 2 Link to comment Share on other sites More sharing options...
WhiteLawns Posted June 22 Share Posted June 22 Thanks for the write up wiz 2 Link to comment Share on other sites More sharing options...
Hoth Posted June 22 Share Posted June 22 When was the last time we had a 10% tor prob in NE? I think there was one around 2010 or so that wound up busting badly due to dogshit lapse rates around 5C. Anyway, looks interesting tomorrow. Should be some solid bangers for sure. 1 Link to comment Share on other sites More sharing options...
wxeyeNH Posted June 22 Share Posted June 22 I didn't realize SPC upgraded parts of our area to "Enhanced Risk". When was the last time that happened? Link to comment Share on other sites More sharing options...
andyhb Posted June 22 Share Posted June 22 See the problem with saying this all is that this is the highest tornado probs issued for this area of the country in quite some time. Given the lack of an EML which is a nearly universal indicator for higher end severe vs. run of the mill severe in this part of the country, I'm wondering why this was upped to a 10% so soon, tbh. 3 Link to comment Share on other sites More sharing options...
weatherwiz Posted June 22 Author Share Posted June 22 We had 10% a few years back (think 2020) and again 5/15/18. Link to comment Share on other sites More sharing options...
Hoth Posted June 22 Share Posted June 22 6 minutes ago, weatherwiz said: We had 10% a few years back (think 2020) and again 5/15/18. Ha, I probably should’ve remembered that, as both events produced tors in my town. 3 Link to comment Share on other sites More sharing options...
Chrisrotary12 Posted June 22 Share Posted June 22 Y’all remember thunderstorms? What are those like? 1 Link to comment Share on other sites More sharing options...
WxWatcher007 Posted June 22 Share Posted June 22 Well, I’m all in for tomorrow 1 Link to comment Share on other sites More sharing options...
JC-CT Posted June 22 Share Posted June 22 Just stopping in to check on the widespread, high end severe weather event for the entire region. Everything looks good? 4 Link to comment Share on other sites More sharing options...
Ginx snewx Posted June 22 Share Posted June 22 Crushed. Tree limbs flying super intense rain Link to comment Share on other sites More sharing options...
WxWatcher007 Posted June 22 Share Posted June 22 Link to comment Share on other sites More sharing options...
weatherwiz Posted June 22 Author Share Posted June 22 2 hours ago, andyhb said: See the problem with saying this all is that this is the highest tornado probs issued for this area of the country in quite some time. Given the lack of an EML which is a nearly universal indicator for higher end severe vs. run of the mill severe in this part of the country, I'm wondering why this was upped to a 10% so soon, tbh. I think another factor to consider too is the difference between stronger and weaker tornadoes. Back in the 2010 setup, which had a 10% hatched area with a lack of an EML, the wording was for a few strong tornadoes (hence the hatched). Lack of EMLs don't necessarily hinder tornado potential, however, they do greatly hinder the likelihood for stronger tornadoes. Another factor to also consider is storm mode. Obviously, one attribute of EMLs is due to the strong capping, they can keep storms discrete which increases the likelihood for thunderstorms to become mature and fully utilize the environment around them. For tomorrow, if storms are able to remain on the discrete side, the environment is supportive for multiple tornadoes so I think that factors into the 10% probability. 2 Link to comment Share on other sites More sharing options...
WxWatcher007 Posted June 22 Share Posted June 22 Today seems like a good example of a discrete cell taking advantage of the environment. Link to comment Share on other sites More sharing options...
WhiteLawns Posted June 22 Share Posted June 22 What is a discrete cell? Just a single storm not a line? 1 1 Link to comment Share on other sites More sharing options...
Torch Tiger Posted June 22 Share Posted June 22 3 hours ago, Hoth said: When was the last time we had a 10% tor prob in NE? I think there was one around 2010 or so that wound up busting badly due to dogshit lapse rates around 5C. Anyway, looks interesting tomorrow. Should be some solid bangers for sure. 6/1/10 was the epic mod-risk? bust that only provided a bit of wind damage in C NH. 1 Link to comment Share on other sites More sharing options...
Torch Tiger Posted June 22 Share Posted June 22 7 minutes ago, WhiteLawns said: What is a discrete cell? Just a single storm not a line? Yeah 1 Link to comment Share on other sites More sharing options...
weatherwiz Posted June 22 Author Share Posted June 22 Sticking with EML's, the reason why they can contribute to widespread, high-end severe weather is they keep the atmosphere capped which prevents cumulus and storms from developing too early. Even if the convective temperature is reached, you'll often need very strong lift to break the cap. So, what this does is allow for extreme instability to develop at the sfc. When the cap breaks, parcels then violently accelerate upwards and because of the steep lapse rates (decrease of temperature with height) in the 700-500mb layer, parcels will continue to rapidly accelerate well into the upper troposphere. This results in rapidly strengthen thunderstorms which can quickly become severe. With the absence of an EML for tomorrow, below is a forecast sounding from the 18z NAM within southwest New Hampshire which I will illustrate a few things: 1. This is a very good shear profile, as evident by the hodograph in the upper right. You have speed shear present, especially in the lowest 3km and you have directional shear present, both in the lowest 3km and especially the lowest 3km. However, note the messy look of the hodograph (circled in orange). This is indicative of a veer-back-veer wind profile which is present in the 700mb to about 450mb level. This is something which can be critical to the potential for tornado outbreaks in the Plains. While this look DOES NOT inhibit tornado potential, it can negate the potential for multiple or several tornadoes. Sometimes, "busts" in the Plains are the result of veer-back-veer wind profiles. 2. With the lack of an EML, mid-level lapse rates are on the weak side. They aren't terrible, forecast to be around 6-6.5C/KM, but what is hurting the lapse rates are these subtle warm layers (circled in blue) and a evident cap just above 500mb. What does this mean? As mentioned above, what steep lapse rates do is enhance upward parcel acceleration. When parcels are able to rapidly accelerate upwards this can result in vigorous updrafts and powerful thunderstorms. Given the atmosphere is moderately unstable, parcels will rapidly accelerate towards the LCL and LFC (note the two are close together). So once we get the proper lift, storms will rapidly develop. As parcels continue to accelerate upwards, the parcel acceleration will slow due to these subtle warm layers and it is very possible the cap above 500mb could hinder the severity as parcels could struggle to continue accelerating. These factors, along with the lack of the EML will prevent a more widespread event from occurring. All in all, while the atmosphere will be conducive for severe weather and a few tornadoes for a good chunk of the region, the area of greatest potential is going to be much more narrow, thus this will not be a widespread, high-end event. 3 Link to comment Share on other sites More sharing options...
weatherwiz Posted June 22 Author Share Posted June 22 9 minutes ago, Torch Tiger said: 6/1/10 was the epic mod-risk? bust that only provided a bit of wind damage in C NH. June 6, 2010 No tornadoes and two swaths of wind damage Link to comment Share on other sites More sharing options...
CoastalWx Posted June 22 Share Posted June 22 20 minutes ago, Torch Tiger said: 6/1/10 was the epic mod-risk? bust that only provided a bit of wind damage in C NH. No it was one supercell that ripped down the pike into BOS. Link to comment Share on other sites More sharing options...
weathafella Posted June 22 Share Posted June 22 1 minute ago, CoastalWx said: No it was one supercell that ripped down the pike into BOS. Wasn’t that the tornado in Webster event when wiz was literally selling hot dogs in a basement somewhere? Link to comment Share on other sites More sharing options...
weatherwiz Posted June 22 Author Share Posted June 22 Just now, weathafella said: Wasn’t that the tornado in Webster event when wiz was literally selling hot dogs in a basement somewhere? That was 6/1/2011 1 Link to comment Share on other sites More sharing options...
Torch Tiger Posted June 22 Share Posted June 22 17 minutes ago, weatherwiz said: June 6, 2010 No tornadoes and two swaths of wind damage Ah right, i mixed up 6/1/11 and 6/6/10 lol 2 Link to comment Share on other sites More sharing options...
Chrisrotary12 Posted June 22 Share Posted June 22 30 minutes ago, weatherwiz said: June 6, 2010 No tornadoes and two swaths of wind damage Man I do not remember this. Looks like an epic SNE supercell. Link to comment Share on other sites More sharing options...
Torch Tiger Posted June 22 Share Posted June 22 30 minutes ago, CoastalWx said: No it was one supercell that ripped down the pike into BOS. There was some wind dmg north, forgot about that cell with the metro BOS damage. Either way the day was a huge bust Link to comment Share on other sites More sharing options...
weatherwiz Posted June 22 Author Share Posted June 22 11 minutes ago, Chrisrotary12 said: Man I do not remember this. Looks like an epic SNE supercell. pretty much lol Link to comment Share on other sites More sharing options...
ineedsnow Posted June 22 Share Posted June 22 What's the timing on this tomorrow? I haven't really looked much into it 1 Link to comment Share on other sites More sharing options...
weatherwiz Posted June 23 Author Share Posted June 23 39 minutes ago, ineedsnow said: What's the timing on this tomorrow? I haven't really looked much into it Between like 2-7 PM for the storms ahead of the pre-frontal trough. Although could see stuff starting to fire as early as 1. There may be some storms with the actual cold front during the late evening and overnight but these may be more on the isolated side. Link to comment Share on other sites More sharing options...
weatherwiz Posted June 23 Author Share Posted June 23 Wow this is a substantial increase in the 21z SPC SREF SIG TOR ingredients versus previous runs. This tends to run wild during low CAPE/high shear events so to see values this high for an environment like tomorrow is pretty wild. 1 Link to comment Share on other sites More sharing options...
WxWatcher007 Posted June 23 Share Posted June 23 28 minutes ago, weatherwiz said: Between like 2-7 PM for the storms ahead of the pre-frontal trough. Although could see stuff starting to fire as early as 1. There may be some storms with the actual cold front during the late evening and overnight but these may be more on the isolated side. 18z NAM has activity up in NNE around 12z tomorrow. Those soundings tomorrow from Albany to HFD look messy but legit. Link to comment Share on other sites More sharing options...
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