2022 Mid-Atlantic Severe Wx Thread (General Discussion Etc)

[midatlanticweather]

[biodhokie]

Tornado Warning
VAC047-061-121900-
/O.NEW.KLWX.TO.W.0037.220912T1837Z-220912T1900Z/

BULLETIN - EAS ACTIVATION REQUESTED
Tornado Warning
National Weather Service Baltimore MD/Washington DC
237 PM EDT Mon Sep 12 2022

The National Weather Service in Sterling Virginia has issued a

* Tornado Warning for...
  South central Fauquier County in northern Virginia...
  Central Culpeper County in northern Virginia...

* Until 300 PM EDT.

* At 237 PM EDT, a severe thunderstorm capable of producing a tornado
  was located near Culpeper, moving east at 15 mph.

  HAZARD...Tornado.

  SOURCE...Radar indicated rotation.

  IMPACT...For those in the direct path of a tornado touchdown,
           flying debris will be dangerous to those caught without
           shelter. Damage to roofs, siding, and windows may occur.
           Mobile homes may be damaged or destroyed. Tree damage is
           likely.

* This dangerous storm will be near...
  Bealeton around 300 PM EDT.

Other locations impacted by this tornadic thunderstorm include Brandy
Station, Elkwood and Remington.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

TAKE COVER NOW! Move to a basement or an interior room on the lowest
floor of a sturdy building. Avoid windows. If you are outdoors, in a
mobile home, or in a vehicle, move to the closest substantial shelter
and protect yourself from flying debris.

&&

LAT...LON 3847 7791 3853 7794 3857 7777 3848 7774
TIME...MOT...LOC 1837Z 266DEG 12KT 3851 7789

TORNADO...RADAR INDICATED
MAX HAIL SIZE...<.75 IN

$$

JMG

[high risk]

23 minutes ago, Kmlwx said:

Yeah some of these cells have the mini supercell look. 

        Hodographs definitely support supercells, although low-level shear *appears* to be insufficient to actually get rotation to the ground.

[midatlanticweather]

SE Loudoun storm looks Interesting! Thoughts?

 

 

[southmdwatcher]

14 minutes ago, midatlanticweather said:

Can you all se this? May be private - Great time lapse of the storm near Culpepper from a friend of mine. May have to capture the video to share. 

 

https://www.facebook.com/100000582945845/videos/5348130565294193/

 

 

Video might be private or only available to his friends. Can not see it.

[aldie 22]

6 minutes ago, midatlanticweather said:

SE Loudoun storm looks Interesting! Thoughts?

 

 

Heavy rain just east of Aldie, not much thunder or lightning and zero wind so far

[midatlanticweather]

6 minutes ago, leesburg 04 said:

Heavy rain just east of Aldie, not much thunder or lightning and zero wind so far

I noticed the highest winds look just north of Stone Ridge. It just has that interesting look and earlier seemed to have some rotation showing. Not certain now as the proximity of radar seems to be showing uniformity. I checked the smaller radar but that does not seem to show anything. Just some winds and rain now. 

 

[aldie 22]

1 minute ago, midatlanticweather said:

I noticed the highest winds look just north of Stone Ridge. It just has that interesting look and earlier seemed to have some rotation showing. Not certain now as the proximity of radar seems to be showing uniformity. I checked the smaller radar but that does not seem to show anything. Just some winds and rain now. 

 

over .80 on that inet rainfall estimate thingy but literally just straight down rain

[midatlanticweather]

Here is the video from down in Culpepper. 

 

 

[MN Transplant]

1 hour ago, leesburg 04 said:

Heavy rain just east of Aldie, not much thunder or lightning and zero wind so far

That cell evaporated as soon as it got to Dulles

[aldie 22]

3 minutes ago, MN Transplant said:

That cell evaporated as soon as it got to Dulles

It was a good rainer for sure

[midatlanticweather]

That Dale City cell - Thunderstorm warned. Looks like it is rotating a bit. 

 

[southmdwatcher]

Tornado warning for the storm crossing the river into Charles County.

[Kmlwx]

Seeing some shear contours on Radarscope on the MoCo cell. Not sure how accurate those are. 

[arlwx]

Tornado warning on the Charles CO/Prince William cell.

[midatlanticweather]

BULLETIN - EAS ACTIVATION REQUESTED
Tornado Warning
National Weather Service Baltimore MD/Washington DC
452 PM EDT Mon Sep 12 2022


The National Weather Service in Sterling Virginia has issued a


* Tornado Warning for...
Northwestern Charles County in southern Maryland...
Southeastern Fairfax County in northern Virginia...
Southeastern Prince William County in northern Virginia...


* Until 515 PM EDT.


* At 451 PM EDT, a severe thunderstorm capable of producing a tornado
was located over Dumfries, or near Quantico, moving east at 15 mph.


HAZARD...Tornado.


SOURCE...Radar indicated rotation.


IMPACT...For those in the direct path of a tornado touchdown,
flying debris will be dangerous to those caught without
shelter. Damage to roofs, siding, and windows may occur.
Mobile homes may be damaged or destroyed. Tree damage is
likely.


* This tornadic thunderstorm will remain over mainly rural areas of
northwestern Charles, southeastern Fairfax and southeastern Prince
William Counties, including the following locations... Cherry Hill
and Mason Neck.

[Kmlwx]

It's far away from TBWI, but MoCo activity seems to have some broad spin at higher levels. 

[AlexD1990]

Bad storm came through the Rehoboth Beach area about 6 this morning. High winds, lots of tree and power line damage. Some spots of the city are without power. Caught a lot of people unawares given the early hour.

Sent from my SM-F711U using Tapatalk

[high risk]

Sunday is potentially interesting around here with good timing for the next front and fairly healthy deep layer shear in place.    The limiting factor is instability, especially due to fairly low dew points.    The HRRR is less enthused about the potential, but as usual, it has by far the lowest dew points among the CAMs.    Other CAMs are more moist, and there are some impressive simulated reflectivity forecasts (hi there, 6Z NAM Nest!).

[Kmlwx]

2 minutes ago, high risk said:

Sunday is potentially interesting around here with good timing for the next front and fairly healthy deep layer shear in place.    The limiting factor is instability, especially due to fairly low dew points.    The HRRR is less enthused about the potential, but as usual, it has by far the lowest dew points among the CAMs.    Other CAMs are more moist, and there are some impressive simulated reflectivity forecasts (hi there, 6Z NAM Nest!).

I've mentioned this before - and my sample size is pretty small/anecdotal - but that trajectory of that "bow" feature on the 6z NAM nest is "classic" - for whatever reason...in many of my memorable damaging wind events (from storms, that is), the highest velocity pixels start at or around Winchester and then rake through the metro area. That simulated reflectivity progression is a pretty classic track.

I suspect the reason we anecdotally see that as a "favored" track is because the WNW to ESE trajectory just matches severe weather squall lines well. Nonetheless, it has me interested. 

[George BM]

Tomorrow loosely reminds me of a poor man's June 16, 2008 and July 27, 2014 when looking at the trough and SLP track. Should current trends hold, I wouldn't be too surprised to see a smaller SLGT show up somewhere in the region or nearby.

[Kmlwx]

FWIW the 12z HRRR looked a bit better in terms of reflectivity versus the 06z run. 

[aldie 22]

Here's what I expect at my house tomorrow 

[CAPE]

...SUMMARY... Scattered severe storms producing large hail and damaging winds are expected from mid to late afternoon across the northern Appalachians and parts of the Mid Atlantic and southern New England through evening. ...Portions of the Appalachians, Mid Atlantic and southern New England... Within a larger-scale upper trough, a lead wave will move from the OH Valley to the Mid Atlantic during the day, providing cooling aloft and midlevel winds of 60-70 kt, enhancing shear. At the surface, low pressure will slowly deepen from Lake Huron into NY, with a front trailing southwestward across PA, WV, eastern KY and Middle TN by late afternoon. Meanwhile, a warm front will develop over southern New England, resulting in destabilization toward evening. Dewpoints will rise into the lower 60s F there, with upper 50s to lower 60s F southwestward along the front where heating and mixing will be stronger. The warm sector will become uncapped by around 18Z from PA southward across WV, VA, KY and TN, with further destabilization 21-00Z from NJ into southern New England. MLCAPE of 1000 J/kg will be common, with locally higher values. Deep-layer shear will be strong beneath the upper jet, with values around 60 kt common from eastern TN to the DelMarVa. Precipitation may be ongoing from OH into PA and western NY early in the day, north of the midlevel jet where temperatures aloft will be cold, and as warm advection around 850 mb translates east. Given cold temperatures aloft, some of this activity could produce small hail. As the air mass destabilizes beneath the cold air aloft, some of these storms may expand and become severe across PA and NJ during the afternoon, producing hail and wind. Later in the evening, additional storms may interact with the warm front where low-level shear will be stronger, and a brief/weak tornado could occur, depending on whether surface temperatures are warm enough for surface-based parcels.

[CAPE]

From Mount Holly AFD this morning-

The upward trend in strength and coverage of convection forecast for this afternoon has continued in the latest guidance this morning. There will be seasonably strong synoptic forcing for convection along with strong deep layer effective shear of 40 kts or perhaps even higher. The primary limiting factor with this setup remains the instability, which is likely to remain around 500-1,000 J/kg. However, the forcing and kinematic environment should be able to overcome the relatively low CAPE to result in scattered strong to locally severe thunderstorms. Additionally, the aforementioned mid- level cooling should also help overcome the less than impressive instability parameters with forecast mid-level lapse rates possibly exceeding 7 C/km. The primary threat of severe weather with these thunderstorms will be locally damaging winds and large hail, however the low- level hodograph curvature will also support a couple brief/weak tornadoes. Effective SRH values look to be around 100-150 m2/s2 with 0-1 km bulk shear around 10-20 kts. LCLs will be around 1000 meters or higher, so this will limit the tornado potential a good bit.

[Stormfly]

Going on 2 week long lightning drought here. (<30 mi)

We really need something but I'm digging the cooler temps!

[Kmlwx]

60 percent chance of a watch per the mesoscale discussion. 

[Kmlwx]

The warned cell to the west has ping pong and ball sized hail in the warning. 

[arlwx]

LWX radio just declared a severe thunderstorm watch.

Quote

 

 

[mappy]

Ah yes 60° cloudy severe weather