high risk Posted June 22, 2017 Share Posted June 22, 2017 4 minutes ago, yoda said: That sounds disturbing if it came true I'm guessing the CF isnt close enough Friday afternoon? as currently modeled, no. The GFS, however, still breaks out some convection. Link to comment Share on other sites More sharing options...
Eskimo Joe Posted June 22, 2017 Share Posted June 22, 2017 12 hours ago, yoda said: lol Fairfax County at 08z SAT Is relevant: Link to comment Share on other sites More sharing options...
yoda Posted June 22, 2017 Share Posted June 22, 2017 12z NAM NEST continues to argue that we get rocked Friday evening into Saturday morning PW county 0800z SAT Link to comment Share on other sites More sharing options...
MN Transplant Posted June 22, 2017 Share Posted June 22, 2017 30 minutes ago, yoda said: 12z NAM NEST continues to argue that we get rocked Friday evening into Saturday morning PW county 0800z SAT Euro track of the surface low seems to be roughly similar to the NAM nest. Maybe a touch south. Link to comment Share on other sites More sharing options...
WxReese Posted June 22, 2017 Share Posted June 22, 2017 37 minutes ago, yoda said: 12z NAM NEST continues to argue that we get rocked Friday evening into Saturday morning PW county 0800z SAT That low LCL will help try to get a spinny down to the surface. It's what I would look for during high shear/low cape events in the southeast. Basically, the lower the cloud base is to the ground, the "easier" it is for a quick spin-up to happen. I went to a workshop at BMX several years ago and that's what they look for too. So... Yeah. Could be one or two spinnies around the region tomorrow afternoon (for us near the BR *IF* anything fires off the mountains) or as main line pushes through. Link to comment Share on other sites More sharing options...
Kmlwx Posted June 22, 2017 Share Posted June 22, 2017 Yoda, just remember - just because parameters are in place does not mean we will get rocked. Link to comment Share on other sites More sharing options...
Tater Tot Posted June 22, 2017 Share Posted June 22, 2017 So would this be an outbreak from Cindy remnants or is it unrelated? I got bored tracking Cindy because she was moving too slow. Link to comment Share on other sites More sharing options...
southmdwatcher Posted June 22, 2017 Share Posted June 22, 2017 I agree the parameters look great but it is not likely at all this will play out. However, the SFC LCL on the sounding above was 171m, is that what we should look for on the LCL or another value? Those of us in LWX tornado country would like to know. Link to comment Share on other sites More sharing options...
boviscopophobic Posted June 22, 2017 Share Posted June 22, 2017 A lot of those soundings are contaminated and shouldn't be taken literally. Link to comment Share on other sites More sharing options...
yoda Posted June 22, 2017 Share Posted June 22, 2017 1 hour ago, boviscopophobic said: A lot of those soundings are contaminated and shouldn't be taken literally. Why is that? DPs in the mid 70s are certainly possible with the type of environment we would be in with PWATs over 2 inches Link to comment Share on other sites More sharing options...
boviscopophobic Posted June 22, 2017 Share Posted June 22, 2017 40 minutes ago, yoda said: Why is that? DPs in the mid 70s are certainly possible with the type of environment we would be in with PWATs over 2 inches Why do I think it's contaminated, or why do I think the contamination is bad? I think it's contaminated for several reasons: 1) saturated or nearly saturated profile through a deep layer; 2) high omega values (synoptic-scale motion typically comes close to falling within the +/- 10 microbar/sec lines); 3) when I go to that lat/lon and forecast hour in the 18Z NAM3k run, it lands in a blob of simulated reflectivity. As for why the contamination is bad, it's simply that a contaminated sounding isn't representative of the broader environment. So one has to be beware of applying the usual conceptual models using contaminated parameter values. It looks like we'll have some screaming 850's so the hodographs might be pretty long in the low levels, I just don't trust those forecast soundings verbatim. Link to comment Share on other sites More sharing options...
yoda Posted June 23, 2017 Share Posted June 23, 2017 Both 18z NAM and the 18z NAM NEST continue to show a potential tornado threat for late tomorrow evening into Saturday morning Link to comment Share on other sites More sharing options...
eurojosh Posted June 23, 2017 Share Posted June 23, 2017 People's thoughts on the 3k Nam wakeup call for tomorrow morning? Link to comment Share on other sites More sharing options...
Kmlwx Posted June 23, 2017 Share Posted June 23, 2017 8 minutes ago, eurojosh said: People's thoughts on the 3k Nam wakeup call for tomorrow morning? Looks like moderate to heavy rain to me on the sim reflectivity. That does not look like severe or anything close to it. Link to comment Share on other sites More sharing options...
high risk Posted June 23, 2017 Share Posted June 23, 2017 28 minutes ago, Kmlwx said: Looks like moderate to heavy rain to me on the sim reflectivity. That does not look like severe or anything close to it. agree. not even sure we'll have thunder, as there really isn't much instability. and a few (albeit outlier) solutions don't get everyone wet. Link to comment Share on other sites More sharing options...
high risk Posted June 23, 2017 Share Posted June 23, 2017 1 hour ago, boviscopophobic said: Why do I think it's contaminated, or why do I think the contamination is bad? I think it's contaminated for several reasons: 1) saturated or nearly saturated profile through a deep layer; 2) high omega values (synoptic-scale motion typically comes close to falling within the +/- 10 microbar/sec lines); 3) when I go to that lat/lon and forecast hour in the 18Z NAM3k run, it lands in a blob of simulated reflectivity. As for why the contamination is bad, it's simply that a contaminated sounding isn't representative of the broader environment. So one has to be beware of applying the usual conceptual models using contaminated parameter values. It looks like we'll have some screaming 850's so the hodographs might be pretty long in the low levels, I just don't trust those forecast soundings verbatim. It's true that the 8z sounding posted by Yoda is "contaminated", in the sense that convection is underway at that site when that profile is extracted, so you've modified the low-level wind field and moistened the low levels. In that sense, bovi (can I call u that for short? ) is correct that it's not representative of the broader, pre-convective environment we want to assess. When I pick a sounding to assess convective potential, I try to grab one right before precip arrives at that location. All that said, there IS decent low-level shear and modest instability before the convection arrives, and others have correctly noted the low LCLs, so it warrants watching. It's interesting that the NAM nest keeps us in the low 80's through Friday night which helps us squeak out some cape. If we cool much more than that, it will probably be tough to get surface-based storms. At this point, my curiosity level is raised, but I'm not yet in. Link to comment Share on other sites More sharing options...
yoda Posted June 23, 2017 Share Posted June 23, 2017 2 hours ago, yoda said: Both 18z NAM and the 18z NAM NEST continue to show a potential tornado threat for late tomorrow evening into Saturday morning Same re 00z NAM and 00z NAM NEST Link to comment Share on other sites More sharing options...
high risk Posted June 23, 2017 Share Posted June 23, 2017 I'm out for the late tonight event. It's still *possible* that we get a spinup or two, I suppose, but the hi-res guidance just doesn't look very impressive. I see no updraft helicity signatures in the HRRR, and the NAM nest has little precip in DC metro. (The Hi-res windows at least have precip for DC and points north). The best chance for SVR might be a couple of isolated cells during the late evening; it's suggested by the Hi-Res Window ARW, although shear is marginal as the better wind fields haven't arrived. Link to comment Share on other sites More sharing options...
Kmlwx Posted June 23, 2017 Share Posted June 23, 2017 Yeah I was never really "in" for this event - but the parameters looked good for a few runs. Even now they look good but no real reflectivity to show for it. Yawn. Link to comment Share on other sites More sharing options...
yoda Posted June 23, 2017 Share Posted June 23, 2017 Severe Tstorm Watch issued just to the north and west of LWX CWA until 10pm Link to comment Share on other sites More sharing options...
yoda Posted June 23, 2017 Share Posted June 23, 2017 Area Forecast Discussion National Weather Service Baltimore MD/Washington DC 300 PM EDT Fri Jun 23 2017 .SYNOPSIS... Tropical air will envelop the area today. A cold front will cross the area late tonight into Saturday. High pressure will return Sunday and persist through early next week. && .NEAR TERM /THROUGH TONIGHT/... In spite of pockets of insolation, atmosphere within the forecast area capped, as evidenced by the lack of agitated cumulus on satpix and just showers on radar. The same cannot be said across western Pennsylvania down the Ohio Valley, in vicinity of the frontal zone. Storms in that region shear-driven, and that will be our concern tonight. Recent runs of HRRR/RAP both depict some enhancement of the showers in Virginia. Given 1500-2000 J/kg SBCAPE, expect some thunder to develop by mid-late afternoon. That area should be scattered in nature and have a diurnal component to it. By 21-22 UTC, the line of thunderstorms, and scattered storms ahead of the line, will be approaching the Potomac Highlands. With loss of daytime heating and residual inhibition, expect a weakening trend in the strength of convection. But, the overall coverage in the Highlands will be increasing. Precipitable water above 2 inches suggests that heavy rain can be expected within any thunderstorm. Latest model guidance (12 UTC cycle) offers a quicker timing. The southwesterly low level jet will be substantive (60-70 kt at 850 mb), so anticipate that some thunder can be expected tonight even without daytime heating. As has been discussed the past couple of days, the question remains whether these storms can root in the boundary layer east of the Appalachians. If they can, it will be busy, with low-topped rotating updrafts. While heavy rain can be expected too, the system overall remains progressive (quicker than previously modeled), which will preclude greater issues. Bottom line... have categorical PoPs crossing forecast area between midnight and 6 am (likely beginning mid-evening), with heavy rain possible. With dewpoints in the lower 70s, low temperatures follow suit. Link to comment Share on other sites More sharing options...
Kmlwx Posted June 23, 2017 Share Posted June 23, 2017 Still out. Link to comment Share on other sites More sharing options...
George BM Posted June 23, 2017 Share Posted June 23, 2017 Now if the timing was different by 12 hours...... Link to comment Share on other sites More sharing options...
Kmlwx Posted June 23, 2017 Share Posted June 23, 2017 Really boring. Link to comment Share on other sites More sharing options...
George BM Posted June 23, 2017 Share Posted June 23, 2017 As of now I'm personally just hoping for at least a narrow line of intense rain that high-res models show for early tomorrow morning to bring a few stronger gusts(maybe 40+ mph). Link to comment Share on other sites More sharing options...
yoda Posted June 23, 2017 Share Posted June 23, 2017 Good amount of TWs coming out of PIT CWA Link to comment Share on other sites More sharing options...
yoda Posted June 23, 2017 Share Posted June 23, 2017 10 minutes ago, yoda said: Good amount of TWs coming out of PIT CWA Severe Weather Statement National Weather Service Pittsburgh PA 553 PM EDT FRI JUN 23 2017 PAC051-232200- /O.CON.KPBZ.TO.W.0009.000000T0000Z-170623T2200Z/ Fayette PA- 553 PM EDT FRI JUN 23 2017 ...A TORNADO WARNING REMAINS IN EFFECT UNTIL 600 PM EDT FOR CENTRAL FAYETTE COUNTY... At 552 PM EDT, a confirmed tornado was located near Uniontown, moving east at 40 mph. HAZARD...Damaging tornado. SOURCE...Weather spotters confirmed tornado. IMPACT...Flying debris will be dangerous to those caught without shelter. Mobile homes will be damaged or destroyed. Damage to roofs, windows, and vehicles will occur. Tree damage is likely. This tornadic thunderstorm will remain over mainly rural areas of central Fayette County, including the following locations: Mill Run, Dunbar, Ohiopyle, Chalkhill and Normalville. Link to comment Share on other sites More sharing options...
yoda Posted June 23, 2017 Share Posted June 23, 2017 Updated HWO from LWX still mentions potential for isolated severe storms tonight Link to comment Share on other sites More sharing options...
Kmlwx Posted June 23, 2017 Share Posted June 23, 2017 Even the HRRR sucks Link to comment Share on other sites More sharing options...
mattie g Posted June 23, 2017 Share Posted June 23, 2017 1 hour ago, yoda said: Good amount of TWs coming out of PIT CWA Yay Link to comment Share on other sites More sharing options...
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