2017 Severe Thread

[Bob Chill]

The RLX radar loop is pretty sick. The line has outflow going now but looked like a lot of hail before that. 

[southmdwatcher]

Charleston WV (KRLX) radar is on steroids right now, the activity is not as strong as the colors on my GR2Analyst, I checked it from Jackson KY, Blacksburg VA, and Wilmington OH.

[SmokeEater]

9 minutes ago, southmdwatcher said:

Charleston WV (KRLX) radar is on steroids right now, the activity is not as strong as the colors on my GR2Analyst, I checked it from Jackson KY, Blacksburg VA, and Wilmington OH.

 

[high risk]

Looking at the evening guidance, the timing has definitely slowed down which makes this a more intriguing event for much of the area.   Both NAM and RAP/HRRR bring 1000+ sfc cape into our area by midday.   The shear gets weaker as we go into the afternoon due to the sfc winds veering, but there looks to be a window (perhaps between 11AM and 2PM) when instability and shear align.    The fail mechanism would be that both the NAM nest and HRRR show a lot of convection through the area during the early morning hours (2 rounds in some HRRR solutions), and while those solutions verbatim clear us out quickly behind that activity, we've all seen svr days here bust due to morning rain/convection reinforcing the wedge and preventing heating.      Thunder with widespread heavy rainfall seems like a fairly good probability during the early hours;  whether there is a SVR event behind that remains to be seen but is not a total longshot either.

[Jebman]

Dont look now but storms are heading for DCA https://radar.weather.gov/Conus/full.php

[MN Transplant]

Not going to do a 3am deep dive, but the severe parameters on the 6z HRRR are pretty good.

[Ellinwood]

I just went through and did a thorough local forecast... a bit better confidence in today's storm potential, mainly between 10am-2pm. The lack of overnight precip is helping, and it does look a tad slower compared to what I was looking at 24 hours ago. Here's hoping some of us get something decent today.

[Jebman]

1 minute ago, WxWatcher007 said:

I woke up randomly (after dreaming about being thrown in jail for storm chasing with an expired license) and checked the SPC. Not bad. Maybe there's a chance up our way lol.

Back to sleep. 

 

You will get flattened by severe storms. Sleep in the basement

[H2O]

http://www.spc.noaa.gov/products/md/md0458.html

 

Mesoscale Discussion 0458
   NWS Storm Prediction Center Norman OK
   0459 AM CDT Thu Apr 06 2017

   Areas affected...Parts of central and eastern North Carolina into
   central and eastern Virginia

   Concerning...Severe potential...Watch possible 

   Valid 060959Z - 061130Z

   Probability of Watch Issuance...60 percent

   SUMMARY...Severe risk will gradually increase across central and
   eastern portions of North Carolina and Virginia over the next few
   hours, which may require watch issuance.

   DISCUSSION...Latest radar loop shows some increase in both coverage
   and intensity of convection across central North Carolina.  This is
   occurring in response to strengthening ascent pivoting
   north-northeastward across the Carolinas and Virginia as mid-level
   short-wave troughing has rounded the base of the Midwestern low and
   is now shifting rapidly toward the mid-Atlantic region.

   The boundary-layer airmass across the NC/VA area remains
   cool/saturated and slightly stable, with temperatures and dewpoints
   in the upper 50s to low 60s.  However, with focused ascent near and
   just ahead of the surface front yielding gradual cooling aloft,
   steady weakening of the low-level inversion is expected to result in
   near moist-adiabatic low-level profiles -- i.e. sufficient for
   storms to eventually become at least near surface-based.  Above the
   lower troposphere, mid-level cooling continues to gradually steepen
   lapse rates, with the overall effect trending toward a thermodynamic
   environment sufficient for vigorous storms.

   Presuming storms can become near surface-based, severe risk --
   including potential for a tornado or two -- will become increasingly
   likely, as currently observed southeasterly surface winds veer and
   increase rapidly with height, supportive of  updraft rotation. 
   While the degree of risk remains a bit conditional/uncertain due to
   the currently stable boundary layer, risk appears great enough to
   warrant consideration of watch issuance over the next 1-2 hours.

   ..Goss.. 04/06/2017

[wasnow215]

 

[H2O]

enhanced a little bit closer to DC but still best spots are south

 

[Kmlwx]

09z HRRR brings up a big slug of steady moderate/heavy rain ahead of any storms that might kill instability. Still gets some cellular stuff/linear stuff after that but best stuff is still down in the ENH. 

[MN Transplant]

17 minutes ago, Kmlwx said:

09z HRRR brings up a big slug of steady moderate/heavy rain ahead of any storms that might kill instability. Still gets some cellular stuff/linear stuff after that but best stuff is still down in the ENH. 

This is an odd situation where the rain doesn't actually hurt us all that much because we aren't currently very unstable.  The storm is advecting the unstable air this way.

[Kmlwx]

3 minutes ago, MN Transplant said:

This is an odd situation where the rain doesn't actually hurt us all that much because we aren't currently very unstable.  The storm is advecting the unstable air this way.

Good point. I'm too scarred from events past where earlier rain killed us

I'm still not sold that places N of DC get anything substantially severe out of this - will be interesting to see how this all evolves. See there's a new TOR watch south. 

[mappy]

Fog and 48 at home. I'll get gusty showers today


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[mattie g]

2 minutes ago, mappy said:

Fog and 48 at home. I'll get gusty showers today


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aka "Mid-Atlantic Severe"

[Kmlwx]

10z HRRR brings a very robust line through. 

[George BM]

1 minute ago, Kmlwx said:

10z HRRR brings a very robust line through. 

After midday as well. But this IS the DMV area so lol......anyway nowcasting time.

[H2O]

First batch of storms I assume is bringing up the warm front

[MN Transplant]

One good thing is that for the most part, we aren't leafed-out yet.  And of course, it always requires a special event to get widespread severe in the DC area.  This doesn't appear it, even though it is interesting.

[mappy]

30 minutes ago, mattie g said:

aka "Mid-Atlantic Severe"

ha, pretty much! 

[Eskimo Joe]

So I gather this "line" is it for us then?

[H2O]

no

 

[snowfan]

I was waiting for that.

[snowfan]

And the thunder rolls........

[mappy]

at least some of you will get some T&L out of this. I'm jelly

[snowfan]

And there's the first T&L. And, it's like chilly outside.......53 attm. 

[Kmlwx]

It wouldn't surprise me if there was no second round later

[H2O]

Wife called to say thunder at home.....with the kids out at the bus stop.

[snowfan]

Just now, H2O said:

Wife called to say thunder at home.....with the kids out at the bus stop.

WTF didn't they cancel school? You should comment on the school district's facebook page!