2026 Mid-Atlantic Severe Storm General Discussion

[Eskimo Joe]

Impressive LSR out of Grafton, WV for that western line "Sustained 35 mph for 5 minutes with gusts to 62 mph."

[MN Transplant]

Bit of initiation happening west of DC from the outflow from the earlier southern storms.

[NorthArlington101]

Bit of initiation happening west of DC from the outflow from the earlier southern storms.

Yep, trying to pop off a bit. Wouldn’t mind a little storm tonight to end the weekend.

[wxmeddler]

Poppin off. Sunset magic hour. Boundary layer decouples and you get a stray gust front (La Plata storm) or subtle s/w aloft and go time.

[Kmlwx]

Garden variety heavy rain in Odenton. 

[Eskimo Joe]

Constant lightning just to my west in Reisterstown. Cats army crawled down to the basement.

[Eskimo Joe]

Interesting radar signature just NW of Sykesville, MD 

[NorthArlington101]

Little bit of lightning in the distance at least. Oh well

[Eskimo Joe]

56 minutes ago, wxmeddler said:

BWER on the E Frederick / W Carroll Cell

 

 

[wxmeddler]

NoVA got skunked. Line to the west is fading. Just showers later I would think.

[Stormchaserchuck1]

Probably my best thunderstorm of the year ongoing

[Eskimo Joe]

That cell in Libertytown/Walkersville appears to have been legit. Some reports of structure damage. . .maybe a tornado?

[snowfan]

Thats quite the cluster from baltimore up into Lancaster co. Impressive amount of lightning. 

[AlexD1990]

Lol apparently this one little part of Virginia is still under the watch...now that's pinpoint forecasting 

[AlexD1990]

Just now, AlexD1990 said:

Lol apparently this one little part of Virginia is still under the watch...now that's pinpoint forecasting 

And also falls Church 

[Eskimo Joe]

Yea definitely looks like a tornado somewhere between Libertytown and New Windsor:

Quote

The Frederick Scanner
9:25 pm: Chief 17 establishing command. Frederick 911 reports possible structure collapse with horse(s) trapped on Bessie Clemson Rd. Requesting ATV/UTV.
9:35 pm: Frederick ECC advises they heard from property owner of the collapsed structure; property owner confirms no horses trapped. Structure is total loss.
9:36 pm: Brush 175 was flagged down by farmer who reports wires down and structural damage.
9:42 pm: Brush 175 reports numerous structures damaged as well as farm equipment rolled over.
9:47 pm: Battalion Chief 902 requesting additional resources to respond to the intersection of Rte. 31 and Bessie Clemson Rd, will disperse resources form that location. Requesting County Highways to respond to assist with clearing debris.

 

[vortex95]

10 hours ago, wxmeddler said:

This is an issue with MADIS. The 83 mph gust is from a sonic anemometer on top of the Bay Bridge. That is the first report. The second 83 mph report in Parole is false, it’s due to a bug that duplicates the Bay Bridge sensor at SHA headquarters in Parole. The lay/lon is wrong in MADIS. The 75 mph gust is from a buoy at the mouth of the Severn.

Are their systematic issues w/ sonic anemometers?   W/ all the new mesonet sites in MD the last few years, are we seeing wind measurement issues often?

[wxmeddler]

22 minutes ago, vortex95 said:

Are their systematic issues w/ sonic anemometers?   W/ all the new mesonet sites in MD the last few years, are we seeing wind measurement issues often?

Sonic Anemometers in general have systematic issues when there is dust / pollen or other particulates in the air. Even rain coming in sideways interferes with the calculations. Which, guess what, is common when there are gust fronts / thunderstorms. Some brands of sonic's have better error rejection than others, but for whatever reason Vaisala's are particularly bad. Which is a shame because it's what both ASOS and many DOT/RWIS networks use.

The "Mesonet" source in the LSR's is a catch all for all different networks including DOT and even some of the PWS stations. It's an issue with the LSR program, there is not enough categories to properly differentiate an actual state mesonet (like MD Mesonet) and a RWIS network like MD SHA's. 

All MD Mesonet sites use traditional propeller anemometers. RM Young 05108's to be exact. MD SHA's RWIS network uses "all-in-one" T/RH/Sonic for reduced maintenance intervals / costs. But they are not good. lol.

[wxdude64]

A few sprinkles adding to the .8-.9" in the gauge from the earlier storm. Looks like MAYBE we get a bit more from the line pushing thru WV in about 45 minutes or so. 

[mappy]

Decent storms last night, picked up .37”

Was watching a left mover up in York County 8-9pm that probably should have be tornado warned well before it actually was. Friend who lives in Stewartstown got hit hard, cell was tornado warned after it passed her but I saw broad rotation on radar well before it hit her. 

[Eskimo Joe]

SPC maintains the 15% for D4 (Thursday) and mentions the usual fail potential alleys: clouds, timing, etc. That being said, any time you get a decent jet just to our north and a reasonably hot/humid airmass...interesting things can happen. 

[Kmlwx]

22 minutes ago, Eskimo Joe said:

SPC maintains the 15% for D4 (Thursday) and mentions the usual fail potential alleys: clouds, timing, etc. That being said, any time you get a decent jet just to our north and a reasonably hot/humid airmass...interesting things can happen. 

Even despite the factors this potential even has going for it - I'm kind of "meh" on it for now. Not necessarily truly meh - but I'm just not feeling it so far. Will see how things look once it gets closer in time. I suspect we won't really have any SOLID clarity until 11am the morning of lol. 

[Eskimo Joe]

1 minute ago, Kmlwx said:

Even despite the factors this potential even has going for it - I'm kind of "meh" on it for now. Not necessarily truly meh - but I'm just not feeling it so far. Will see how things look once it gets closer in time. I suspect we won't really have any SOLID clarity until 11am the morning of lol. 

I'm kind of in the same boat as you. Still, we've seen what marginal surface instability and good dynamics can do in these parts.

[Kmlwx]

6 minutes ago, Eskimo Joe said:

I'm kind of in the same boat as you. Still, we've seen what marginal surface instability and good dynamics can do in these parts.

Truth! Severe weather around here is a perfect example of what tiny factors can change about an event...no two events are the same even with seemingly nearly identical parameters. 

Snow gets all the glory of forecast busts - but I really think severe weather busts are MUCH more finicky. 

[yoda]

This is what LWX had in their AFD this morning re Thursday 

Beginning Thursday, a strong surface low will push east past the
Great Lakes with a stemming cold front that will push across the
Northeast and Mid-Atlantic. This cold front could result in multiple
showers and thunderstorms throughout the region, with some becoming
severe. There is already a 30%-45% severe probability noted in
NCAR`s AI model, and a 15%-30% severe probability noted in CSU`s ML
model. Timing and exact hazards are still the primary uncertainties
being 5 days out, but early markers are definitely showing an
early widespread severe risk with this system.

[Kmlwx]

I *will* say that the NCAR AI maps are VERY robust for Thursday - but they do tend to look at lot more serious than CSU and CIPS in general. So take with a grain of salt. 

[Kmlwx]

Also not that it matters a ton (also it's being sunset soon) - the SREF maps over on the SPC page are already showing a mean Derecho Composite of 3 for part of Thursday afternoon/evening. 

[yoda]

Afternoon AFD from LWX 

KEY MESSAGE 1...Heat and humidity returns for Thursday, along
with chances for severe thunderstorms.

A potent shortwave on the southern periphery of a much broader upper
low over Canada will track through the Great Lakes on Wednesday
night. This will force a highly anomalous area of low pressure
to track across the eastern Great Lakes. In fact, this low could
potentially break all-time minimum sea level pressure records for
the month of June across portions of Wisconsin and Michigan as it
tracks through later Wednesday into Wednesday night. Most solutions
have this low tracking across southern Ontario and Quebec at around
985-990 hPa on Thursday. An unseasonably strong wind field aloft
will accompany the highly anomalous low, as 850 hPa winds climb to
around 30-50 knots and 500 hPa winds increase to in excess of 50
knots. Low-level south to southwesterly flow will also draw a hot
and humid airmass north into the area. Temperatures are forecast to
soar into the upper 80s and 90s across the bulk of the forecast
area, while dewpoints increase into the mid to upper 60s. This
overlap of a very hot and humid airmass with highly anomalous winds
aloft raises concerns for severe thunderstorms locally on Thursday.
It`s still to early to get into the finer scale details, but
soundings show an environment that is very favorable for the
production of damaging winds. SPC currently has the entire area
outlooked with a Slight Risk for severe thunderstorms. We`ll
continue to monitor this threat for severe thunderstorms over the
coming days.

Even outside of thunderstorms, winds should be breezy, potentially
gusting in excess of 30 mph even in clear air. The combination of
heat and background winds will be something that we don`t experience
often here in the Mid-Atlantic.

[wxmeddler]

80 mph straight line winds determined by LWX survey last night near Libertytown (Frederick Co.)
https://partnerservices.nws.noaa.gov/products/cache/166-2026/PNSLWX/187943434c0858f4f13424bc30b0894e