2023 Mid-Atlantic Severe Wx Thread (General Discussion)

[WEATHER53]

4 hours ago, WxUSAF said:

Storm to the east 

 

Underneath of that is hellI.

is that over  30,000?

 

[WEATHER53]

I got pounded three times in 2010 with 70+ gusts and have not reached 70 since. Even derecho was 60-65. Lots of tree damage with first one in 2010 .  and Kenny wasn’t that late June ? one where Brookside Gardens had 90moh gusts?  There was a plaque  over there about it at one time 

[Random Chaos]

4 hours ago, Eskimo Joe said:

IMO, June 13, 2013: https://www.spc.noaa.gov/exper/archive/event.php?date=20130613

That’s the storm that dropped a tornado on my parent’s back yard, taking down 2 30"+ diameter trees parallel to their house and topping another 30" diameter tree.

June 13, 2013:

[yoda]

We try again today lol... 2/15/15 from SPC with talk of a few supercells possible 

Morning AFD from LWX below:

 

For the rest of today through tonight, an upper-level trough
will slide through the Ohio Valley into New England while high
pressure remains offshore. A south to southwest flow will
continue to usher in very warm and humid conditions to the area.
There should be enough breaks of sunshine this morning, and also
behind the aforementioned MCV this afternoon for the atmosphere
to destabilize. Latest guidance shows around 1.5-3 KJ/KG of
MLCAPE developing ahead of a weak cold front/surface trough that
will most likely move into the area later this afternoon into
this evening from the west (associated with upper-level trough
axis to our north). The moderate CAPE will combine with stronger
shear profiles, increasing the threat for some severe storms
with damaging wind gusts and large hail being the primary
threats. However, the low-level flow may be backed somewhat,
increasing low-level shear, so an isolated tornado cannot be
ruled out. The best chance for severe storms and an isolated
tornado will be around mid afternoon through this evening near
and east of the Blue Ridge/Catoctin Mountains (where instability
will be highest east of the weak cold front/surface trough).

When comparing the atmosphere to yesterday thermodynamically,
it is similar. There was a small stable layer along with mid-
level clouds at times that caused convection to be more
sporadic. There is a similar setup today, but it does appear
that the low-level forcing will be a bit stronger with the weak
boundary moving in. Therefore, we went areal with the pops with
scattered to numerous showers and thunderstorms (highest pops
near/east of Blue Ridge and Catoctins).

Convection should wane later tonight with the loss of daytime
heating. Warm and humid conditions will persist with patchy fog
possible, especially in areas that do receive rainfall

[yoda]

Lol at the impressive UD Helicity swath just north of the DC metro this afternoon on the 06z NAM NEST 

[Kmlwx]

16 minutes ago, yoda said:

Lol at the impressive UD Helicity swath just north of the DC metro this afternoon on the 06z NAM NEST 

Given that I won't be at home during that time - mark my words it will happen now. 

[Eskimo Joe]

9 hours ago, Random Chaos said:

That’s the storm that dropped a tornado on my parent’s back yard, taking down 2 30"+ diameter trees parallel to their house and topping another 30" diameter tree.

June 13, 2013:

That was my first cradle to grave damage assessment. I was in the Emergency Operations Center and started to map out the initial damage points. It became pretty clear within about 30 min we had a tornado. Got out the next day at 7am with NWS to start looking at it.

[Kmlwx]

I saw some sunny breaks this morning while on the road. Pesky patch of clouds...let's see how this plays out.

[high risk]

1 hour ago, yoda said:

Lol at the impressive UD Helicity swath just north of the DC metro this afternoon on the 06z NAM NEST 

      That is super impressive!    It seems to be associated with a very weak surface low pressure center that backs and strengthens the low-level winds.    Outlier for now, but it's worth noting that the forecast soundings across the board do support at least brief supercell structures this afternoon.     NAM Nest scenario aside, the low-level winds are too weak for tornadoes, but I'd certainly take a few supercells rolling through.

[Kmlwx]

7 minutes ago, high risk said:

      That is super impressive!    It seems to be associated with a very weak surface low pressure center that backs and strengthens the low-level winds.    Outlier for now, but it's worth noting that the forecast soundings across the board do support at least brief supercell structures this afternoon.     NAM Nest scenario aside, the low-level winds are too weak for tornadoes, but I'd certainly take a few supercells rolling through.

I honestly just want to see if we can do an region-wide linear storm mode ever again. I know we've had some stuff blow up south of the area that's been pretty widespread - but I just miss the days of a squall (even if not over severe limits) going from NW to SE or W to E across the entire area. Splotchy severe seems to be the reigning champion here for a while. 

[Kmlwx]

Worth noting that as usual, the HRRR is mixing dews down into the lower to mid 60s in many areas this afternoon. NAM nest (6z run, at least) keeps most areas in the 70+ range. Despite this, the HRRR still fires t'storms across the area but without the supercharged UH swath across the Central Maryland area. 

I could be wrong, of course - but given the moist airmass in place - I really don't think we are going to mix down 10 degrees on the dews. My PWS (accuracy questionable, of course) is showing a dew of 74.5 right now. It may come down some - but I think 68-70 is far more likely when storms fire versus 62 as shown on the HRRR. 

We could still fail from a stable layer, lack of forcing, or countless other ways - but I like our chances better today as a whole than yesterday. 

[Stormfly]

18 minutes ago, Kmlwx said:

I honestly just want to see if we can do an region-wide linear storm mode ever again. I know we've had some stuff blow up south of the area that's been pretty widespread - but I just miss the days of a squall (even if not over severe limits) going from NW to SE or W to E across the entire area. Splotchy severe seems to be the reigning champion here for a while. 

Yeah classic bow moving NW to SE over this region has not been seen in a long time.

[Kmlwx]

FV3 (0z run) looks abysmal for storm chances for many this afternoon. ARW and ARW2 look a bit better but not spectacular. HRDPS looks splotchy but passable for now. Yet another day of model solutions all over the map. 

[Random Chaos]

1 hour ago, Eskimo Joe said:

That was my firs cradle to grave damage assessment. I was in the Emergency Operations Center and started to map out the initial damage points. It became pretty clear within about 30 min we had a tornado. Got out the next day at 7am with NWS to start looking at it.

To this day I still feel NWS under-graded that tornado. They called it a long track EF0, but my parents property appeared to have around 90mph EF1 damage. I know NWS never visited that location on the track. The official assessment talked about downtown Rockville and Sping Valley locations mostly, and ignored west Rockville where the damage was mostly wooded residential and park areas. One house up the street from my parents had 7 mid-sized trees land on it, shifting the house on it’s foundation but luckily only doing minor roof damage; they were able to repair it in a few months.

One thing clear from the photos my parents sent me was that it was a tornado: the 30" diameter oak was uprooted such that the tree fell to the right but the pivot point was above the rootball with the rootball to the left of the hole it came out of. Straight line winds would have it pivot from then forward edge of the rootball, and instead the entire rootball shifted about 8-10 feet left of that point, indicating the tree was lifted partially out of the ground then pushed over.

[Random Chaos]

17 minutes ago, Kmlwx said:

FV3 (0z run) looks abysmal for storm chances for many this afternoon. ARW and ARW2 look a bit better but not spectacular. HRDPS looks splotchy but passable for now. Yet another day of model solutions all over the map. 

I was looking at current radar vs current models and HRRR, FV3, and NAM3K aren’t picking up what is currently on radar while HRDPS is.

[yoda]

Updated morning portion of the LWX AFD... rest of it after this is the same as the early morning disco 

NEAR TERM /THROUGH TONIGHT/...
In response to the remnant mesoscale convective vortex (MCV),
light radar returns are noted across the region. Based on their
appearance, these should not amount to much in terms of
precipitation amounts. Like yesterday, cloud cover is fairly
extensive, although there are some breaks seen on the visible
satellite imagery. Considering the thermodynamic environment as
shown on the 12Z IAD sounding, mid-level lapse rates are
somewhat marginal, averaging around 6 C/km. Low-level lapse
rates should quickly steepen given daytime heating which would
yield higher downdraft CAPE (DCAPE). Capping also appears to be
less of an issue, accompanied by plenty of 0-6 km shear which
runs around 35 knots. But overall, much will depend on scouring
some of this early/mid morning cloud cover.

[high risk]

49 minutes ago, Kmlwx said:

FV3 (0z run) looks abysmal for storm chances for many this afternoon. ARW and ARW2 look a bit better but not spectacular. HRDPS looks splotchy but passable for now. Yet another day of model solutions all over the map. 

  12Z FV3 looks better, at least for the north side of DC.     All of the CAMs look good for *some* coverage of storms, although there will be winners and losers for sure.    And the area of highest potential is still all over the map.    It's worth noting that several other CAMs have joined the NAM Nest with a weak surface low forming, which creates a mesoscale corridor of good wind profiles, and there are now modest to impressive single UH tracks in several solutions.

  Of course, need to get these damn clouds and morning showers out of here......

 

[yoda]

10 minutes ago, high risk said:

  12Z FV3 looks better, at least for the north side of DC.     All of the CAMs look good for *some* coverage of storms, although there will be winners and losers for sure.    And the area of highest potential is still all over the map.    It's worth noting that several other CAMs have joined the NAM Nest with a weak surface low forming, which creates a mesoscale corridor of good wind profiles, and there are now modest to impressive single UH tracks in several solutions.

  Of course, need to get these damn clouds and morning showers out of here......

 

Impressive... most Impressive lol

Some clearing here... can see some blue sky off to my west

[EastCoast NPZ]

47 minutes ago, yoda said:

Updated morning portion of the LWX AFD... rest of it after this is the same as the early morning disco 

NEAR TERM /THROUGH TONIGHT/...
In response to the remnant mesoscale convective vortex (MCV),
light radar returns are noted across the region. Based on their
appearance, these should not amount to much in terms of
precipitation amounts. Like yesterday, cloud cover is fairly
extensive, although there are some breaks seen on the visible
satellite imagery. Considering the thermodynamic environment as
shown on the 12Z IAD sounding, mid-level lapse rates are
somewhat marginal, averaging around 6 C/km. Low-level lapse
rates should quickly steepen given daytime heating which would
yield higher downdraft CAPE (DCAPE). Capping also appears to be
less of an issue, accompanied by plenty of 0-6 km shear which
runs around 35 knots. But overall, much will depend on scouring
some of this early/mid morning cloud cover.

That's for sure.  Was under these all morning and didn't produce a single drop of rain.

[Eskimo Joe]

Looks like the low level junk is eroding out. Seems like we're not too far behind for today. I'm planting a lot of perennials today so I really need a good soaking this afternoon.

[SnowenOutThere]

Clouds have broken and the sun has been out for a bit in fairfax.

[yoda]

 

 

[Kmlwx]

I'm seeing some blue skies around now. 

[George BM]

Watching what that batch of convection in eastern WV will do over the next few hours.

[George BM]

Upgraded to an ENH at 1630z.

[yoda]

Oh I see SPC... 30 wind and 15 hail (which was made much smaller)

 

 

[high risk]

1 hour ago, George BM said:

Watching what that batch of convection in eastern WV will do over the next few hours.

 

    Would expect an MD within the next hour as that convection approaches the better environment.    The CAMs all turn that into either the show or part one of the show.

[Kmlwx]

HRRR continues to mix dews down into the mid 60s in spots. My dewpoint still has lowered a bit (to around 70) - but still think mid 60s may be a reach. 

[Eskimo Joe]

5 minutes ago, Kmlwx said:

HRRR continues to mix dews down into the mid 60s in spots. My dewpoint still has lowered a bit (to around 70) - but still think mid 60s may be a reach. 

HRRR mix out bias!

[mappy]

FWIW: 82/72 with sunny skies in Parkton