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

[leesburg 04]

5 hours ago, mattskiva said:

Stuck in between the two training areas all day, lots of distant thunder but only about 0.25" here.  3" showing up on precip maps 10 miles to my west and 15 miles to the east of here.

 

Yeah we got just enough 

[BlizzardNole]

Managed 0.64 which is decent but was hoping for 1.0 for the dry ground.  Much heavier amounts close by in all directions.  That's Germandesert in summer!

[calm_days]

11 hours ago, GATECH said:

Outside a tropical system, I can’t really recall a straight north to south storm movement scenario in the past like we are seeing today…very unique

yes;

Some of the aspects of the overall pattern can be seen in these water vapor images i think!!

https://i.imgur.com/T4svC8I.mp4

https://i.imgur.com/2Jcm0SS.mp4

 

copy and paste link for fullscreen or click for a smaller view that can be expanded!

 

[GATECH]

1.31” since yesterday.  Not bad, the grass will live another day or 2

[jacindc]

According to https://www.iweathernet.com/total-rainfall-map-24-hours-to-72-hours, I got 1.47" on the south side of Capitol Hill, but two blocks from me got 1.95". That was a sharp gradient.

 

[Kmlwx]

Strong CIPS signal in the extended panels at 168hrs

[Kmlwx]

HR132 from the 12z CIPS run. 

[George BM]

Causally looking at Saturday and the early/mid week timeframe next week for local severe chances.

[Kmlwx]

3 minutes ago, George BM said:

Causally looking at Saturday and the early/mid week timeframe next week for local severe chances.

LWX has been watching this afternoon is a storm or two can break through the low odds. 

We are right about the time when our severe events get less widespread and more spotty (but can still pack major punches). These types of severe events tend to be harder to diagnose/see from farther out. I'm definitely watching the weekend. July tends to need a big time trigger to do widespread severe...otherwise it's the kind of storms that blow up nice and tall but collapse after a short time. Lottery odds...if you get under one you could get minivan sized hail for a few mins before the storm kills itself. 

[Kmlwx]

So far it's an empty radar. Seems the signal for an isolated storm has backed off further on the models. Most guidance has a shower or two around, though. 

[mappy]

Is Saturday a pop up storm kind of day? Having people over and wondering how it could be

[Kmlwx]

20 minutes ago, mappy said:

Is Saturday a pop up storm kind of day? Having people over and wondering how it could be

Seems it could be more widespread but TBD of course 

[mappy]

28 minutes ago, Kmlwx said:

Seems it could be more widespread but TBD of course 

Thanks! 

[Kmlwx]

Just now, mappy said:

Thanks! 

I don't think I was much help - just model perusing! 

[mappy]

Just now, Kmlwx said:

I don't think I was much help - just model perusing! 

I’ve looked at them too. Gfs seemed more robust while euro was hit and miss. 

[Maestrobjwa]

Happy Derchoversary everybody!

 

 

[WxWatcher007]

An all-time event for the region. Just extraordinary.
 

 

[George BM]

This moment ten years ago I was standing outside with a strange sustained west wind picking up in strength immediately ahead of the gust front with a growing roar approaching from the west. - Herndon, VA.

[GramaxRefugee]

For the Derecho.....

This NWS product is worth looking at. A lot of effort must've gone into this. Impressive graphics.  Link from the LWX page....

http://storymaps.arcgis.com/stories/a86e8fc4fc814521b127602feb33db10

 

[Kmlwx]

Seems a few good storms could be in the offing for this afternoon. Better chance tomorrow. Summer doldrums otherwise! 

[George BM]

52 minutes ago, Kmlwx said:

Seems a few good storms could be in the offing for this afternoon. Better chance tomorrow. Summer doldrums otherwise! 

I definitely like the very steep lapse rates from ~650mb to the surface being advertised on CAMs such as the HRRR for this afternoon. DCAPE looks fairly decent as well. Could see a strong downburst in a spot or two later.

[Stormfly]

On 6/29/2022 at 10:02 PM, WxWatcher007 said:

An all-time event for the region. Just extraordinary.
 

 

Transformer explosions rarely happen.  The flashes visible are arc faults or simply power flashes where something comes in contact with lines or a line is on the ground arcing producing lots of light.  Pole mounted transformers are extremely robust, I've seen secondary faults burn through an entire pole and while the pole and transformer ended up on the ground, the transformer was still functional but damaged only from the fall!

In substations where larger transformers are used where 500kV may be stepped down to 33kV, for example, faults here are quite spectacular and if it goes up in flames its usually due to the oil heating up to the point where the internal pressure reaches limits and safety devices vent the oil which instantly vaporizes and ignites when it contacts something hot (like an arc).

Well known events involving substations include NYC:
 

 

Closer to home, there was an incident on 12/21/2012, the day the world was supposed to end.   Freaked a lot of folks out in the Annapolis area IIRC.

During strong winds at night when your lights start flickering, dimming or going out and come back on, listen carefully.  You may hear humming.  And if you go outside you may see that eerie looking glow.  In rural areas where overhead lines and trees are close together, this is commonplace.  It's also annoying when a limb large enough to not be cleared by reclosers trips them out and you have to wait for crews to clear the fault.

 

 

[WxWatcher007]

1 hour ago, Stormfly said:

Transformer explosions rarely happen.  The flashes visible are arc faults or simply power flashes where something comes in contact with lines or a line is on the ground arcing producing lots of light.  Pole mounted transformers are extremely robust, I've seen secondary faults burn through an entire pole and while the pole and transformer ended up on the ground, the transformer was still functional but damaged only from the fall!

In substations where larger transformers are used where 500kV may be stepped down to 33kV, for example, faults here are quite spectacular and if it goes up in flames its usually due to the oil heating up to the point where the internal pressure reaches limits and safety devices vent the oil which instantly vaporizes and ignites when it contacts something hot (like an arc).

Well known events involving substations include NYC:
 

 

Closer to home, there was an incident on 12/21/2012, the day the world was supposed to end.   Freaked a lot of folks out in the Annapolis area IIRC.

During strong winds at night when your lights start flickering, dimming or going out and come back on, listen carefully.  You may hear humming.  And if you go outside you may see that eerie looking glow.  In rural areas where overhead lines and trees are close together, this is commonplace.  It's also annoying when a limb large enough to not be cleared by reclosers trips them out and you have to wait for crews to clear the fault.

 

 

Great info, thanks for sharing! 

I remember that NYC event. People thought the aliens finally arrived lol. 

[wxtrix]

i’ve been hearing the thunder from this storm for the last half hour. i hope it misses me.

 

[North Balti Zen]

 

[midatlanticweather]

https://www.spc.noaa.gov/products/md/md1314.html 

[Stormfly]

Whole lot of lightning to our west!

[BlizzardNole]

Painfully close miss to the north for my parched yard.  Hope we get another shot at one later.  The nice thing is it sucked a lot of heat out of the air

[biodhokie]

SEVERE THUNDERSTORM WATCH OUTLINE UPDATE FOR WS 417
NWS STORM PREDICTION CENTER NORMAN OK
310 PM EDT FRI JUL 1 2022

SEVERE THUNDERSTORM WATCH 417 IS IN EFFECT UNTIL 700 PM EDT
FOR THE FOLLOWING LOCATIONS

MDC003-005-013-015-017-021-025-027-031-033-043-510-012300-
/O.NEW.KWNS.SV.A.0417.220701T1910Z-220701T2300Z/

MD
.    MARYLAND COUNTIES INCLUDED ARE

ANNE ARUNDEL         BALTIMORE           CARROLL
CECIL                CHARLES             FREDERICK
HARFORD              HOWARD              MONTGOMERY
PRINCE GEORGES       WASHINGTON


MARYLAND INDEPENDENT CITIES INCLUDED ARE

BALTIMORE CITY
$$

[dailylurker]

Nice loud storm passed mostly south of my area along 70. Lots of rumbling and some beneficial rain.