3/16/26 Severe Weather Event Thread (Moderate Risk) | Latest: 15% TOR, 60% WIND, 5% HAIL

[LeesburgWx]

How we looking? Bust or Legit?

[yoda]

Morning discussion from LWX 

DISCUSSION...
KEY MESSAGE 1...A strong cold front pushes across the forecast area
Monday, bringing gusty winds and potential for severe thunderstorms
capable of producing significant damaging winds and tornadoes.

A possibly high-impact severe weather event may unfold across
the Mid-Atlantic region today, especially during the afternoon
to evening hours. The Storm Prediction Center has maintained the
Moderate Risk (Level 4 out of 5) area which extends from east
of the Blue Ridge Mountains to the Chesapeake Bay. The one
exception to this is northeastern Maryland which is in an
Enhanced Risk (Level 3 out of 5) given the cooler bay waters
could weaken approaching convection.

The early morning surface analysis depicts a stout cyclone
racing across northern Indiana which is accompanied by a squall
line which has jumped out ahead of the cold front. Closer to the
local area, a wavy frontal zone arcs from just south of St.
Marys County westward across Richmond and back into southern
West Virginia. While surface wind vectors are out of the east,
the primarly low-level steering flow is from the south. Light
overrunning showers continue to lift northward through the
region. The combination of weak forcing and ample low-level
stability is yielding rather scant rainfall totals, generally
averaging under 0.10 inches. Otherwise, low stratus will remain
a fixture in the early morning forecast which comes with
temperatures in the 50s to low 60s.

Ample poleward flow within the warm conveyor belt should help
push this warm front north of the Mason-Dixon Line by just after
daybreak. While the 00Z IAD sounding is now outdated, its
vertical wind profile indicates precisely why the severe threat
has a high ceiling today. The 0-6 km wind fields were
characterized by substantial cyclonic turning of the winds with
height, coupled with surface backed flow. In the net, this
sounding yielded a 0-1 km storm-relative helicity of 506 m2/s2
which is off the charts. However, the profile lacked any
instability, particularly headed toward the more stable
overnight hours.

Despite only being 12 to 18 hours out, the 00Z high-resolution
model suite continues to show timing and evolution differences.
There are a couple of areas to keep a close eye on: (1) The
squall line racing across eastern Kentucky/Ohio right now (331
AM) and (2) The low stratus deck in place. In terms of recovery,
this low cloud deck will need to erode to allow the 500 to 750
J/kg of surface-based CAPE to materialize. All signs point
toward gradual erosion of these stratus clouds, but it may take
until after the noon hour. Even then, these could just be breaks
in the clouds. Any additional insolation through the day will
help increase instability in the presence of substantial
vertical shear (0-6 km values around 55 to 65 knots). The other
aspect of the forecast references the upstream squall line. How
long this holds on and its cirrus canopy overspreading the
region will also play some roles in how convective development
evolves.

With the degree of deep-layer shear in place, any of the pre-
frontal discrete cells will pose a risk of becoming a supercell.
These would be most conducive to producing a tornado,
particularly if the enlarged 0-1 km and 0-3 km hodographs hold
as true as forecast soundings depict. However, some of the
high-resolution guidance show a slew of cells firing up at once
which would favor more competition amongst them. This would
diminish the tornado risk as multicell convection dominates. At
the same time, another squall line is likely to form off the
higher terrain this afternoon. While the vertical shear vector
does not align perpendicular to the forming line, enough angle
between the two should favor evolution into a quasi-linear
convective system (QLCS). These are prone to producing spin up
tornadoes along any kinks in the line. Where this line bows out
is where the 70 to 80 mph wind gust possibliity will be
maximized. All of this slides eastward at a fairly hefty speed,
perhaps 40 to 50 mph. Severe convection is expected to near the
I-95 corridor during the evening rush hour before exiting the
Chesapeake Bay by the early/mid evening hours. Some weakening is
possible east of I-95 as the system begins to ingest the colder
Chesapeake Bay waters.

Outside of convection, conditions will be gusty today as a deep
surface low tracks across the Great Lakes. Strengthening
southerly flow may gust to 30 to 40 mph, with gusts closer to 50
mph in the mountains. Additionally, this also could occur in
northeastern Maryland given this region stays in the warm sector
longer and perhaps free of convection. Wind Advisories are in
place across these areas which may see 50 mph gusts outside of
any convection. Eventually a powerful cold front will usher in a
cold and blustery air mass to the region. Gusts may be strong
enough in the mountains to support additional Wind Advisories.

All and all, ensure everyone has multiple ways to receive
hazardous weather information from the National Weather
Service. When it comes to Tornado and Severe Thunderstorm
Warnings, know where your safe place is and remain there until
the storm has moved through and alerts have ended.

[LP08]

Absolutely pouring in that thin line over the beltway.

[nj2va]

Balmy, rain. 

[LeesburgWx]

I’m ready for whatever today brings. Hoping for something noteworthy, but please don’t knock my trees down

[dailylurker]

Looks to me like a rainy morning. Ugh.. Hopefully this shit clears out. 

[mappy]

Breezy foggy showery - thats good for severe right? 

[EstorilM]

Just got into work (across from Sterling WFO) and it actually appears that this low cloud deck is rapidly thinning out behind the earlier showers. 
 

That line of showers wasn’t very dense and didn’t really fill in, at least where I live. 
 

I’m actually feeling a little better about this vs late last night when the high res models started the bust scenario. 

[snowfan]

8 minutes ago, dailylurker said:

Looks to me like a rainy morning. Ugh.. Hopefully this shit clears out. 

HRRR has been rock steady since yesterday that we don't lose the clouds today.

[Eskimo Joe]

3 minutes ago, EstorilM said:

Just got into work (across from Sterling WFO) and it actually appears that this low cloud deck is rapidly thinning out behind the earlier showers. 
 

That line of showers wasn’t very dense and didn’t really fill in, at least where I live. 
 

I’m actually feeling a little better about this vs late last night when the high res models started the bust scenario. 

Water vapor satellite imagery is actually encouraging.

[nj2va]

3 minutes ago, snowfan said:

HRRR has been rock steady since yesterday that we don't lose the clouds today.

Excellent, if true. 

[Kmlwx]

10z HRRR has some pre-line stuff and then a decent looking line later on. 

[dailylurker]

Just now, Kmlwx said:

10z HRRR has some pre-line stuff and then a decent looking line later on. 

That doesn't sound that exciting lol

[LeesburgWx]

Clouds here are pretty thin right now

[Kmlwx]

2 minutes ago, dailylurker said:

That doesn't sound that exciting lol

It actually tries for like 3ish rounds  - I'm not sure I buy that but who knows. It has the pre-frontal stuff, a line in the afternoon, and then a frontal line it looks like of heavily forced showers with high winds. Has some UH swaths come through around 3-4pm. 

[dailylurker]

1 minute ago, Kmlwx said:

It actually tries for like 3ish rounds  - I'm not sure I buy that but who knows. It has the pre-frontal stuff, a line in the afternoon, and then a frontal line it looks like of heavily forced showers with high winds. 

I was hoping to chase down an EF3 with my work truck this afternoon over on the eastern shore. I need sunshine and super cells.

[Eskimo Joe]

2 minutes ago, Kmlwx said:

It actually tries for like 3ish rounds  - I'm not sure I buy that but who knows. It has the pre-frontal stuff, a line in the afternoon, and then a frontal line it looks like of heavily forced showers with high winds. Has some UH swaths come through around 3-4pm. 

Peak heating

[EstorilM]

5 minutes ago, Kmlwx said:

It actually tries for like 3ish rounds  - I'm not sure I buy that but who knows. It has the pre-frontal stuff, a line in the afternoon, and then a frontal line it looks like of heavily forced showers with high winds. 

Yeah I'd much rather trade that in for two rounds lol - I think that first round might really ruin things for us, but who knows. My primary PWS in Middleburg is already 64 deg w/ DP of 62.8. 

[Kmlwx]

My benchmark for crapvection in these events if 9-10am. If things look socked in by 9 or 10 am, it's often times a bust. If there's ANY breaks in sun by that time, it ramps the threat level up substantially. Even then, still ways it can be muted. 

[EstorilM]

4 minutes ago, Kmlwx said:

My benchmark for crapvection in these events if 9-10am. If things look socked in by 9 or 10 am, it's often times a bust. If there's ANY breaks in sun by that time, it ramps the threat level up substantially. Even then, still ways it can be muted. 

lol that's exactly what I just told someone at work (re 9-10am we'll get a "feel" for the day so-to-speak.) 

Then again, there are still a LOT of ingredients at play here beyond cape. Mets seem to think there's sufficient lifting, so we may not be too dependent on daytime heating. It'll still be an interesting day regardless... and it looks like those winds will almost certainly mix down either way as well. 

[TSSN+]

5 minutes ago, Kmlwx said:

My benchmark for crapvection in these events if 9-10am. If things look socked in by 9 or 10 am, it's often times a bust. If there's ANY breaks in sun by that time, it ramps the threat level up substantially. Even then, still ways it can be muted. 

Lwx said any clearing won’t be till after 12 

[Kmlwx]

1 minute ago, TSSN+ said:

Lwx said any clearing won’t be till after 12 

More just my general baseline for days like today 

[hstorm]

31 minutes ago, nj2va said:

Excellent, if true. 

I don’t get why anyone roots for severe storms. Especially in populated areas. There are real people with real homes whose lives could be upended. My hope is for a complete bust. 

[Kmlwx]

4 minutes ago, hstorm said:

I don’t get why anyone roots for severe storms. Especially in populated areas. There are real people with real homes whose lives could be upended. My hope is for a complete bust. 

Every year we have the ethics debate. I can't speak for others - but I am not "rooting for severe storms" in the damage sense. I like interesting weather - and I/we/us have no control over it. If it's going to be a substantial severe day, I am going to track it with enthusiasm. Nothing we say or do is going to change the outcome. 

 

Consider this - firefighters on a quiet shift will welcome a call coming in...

[WxUSAF]

If for no other reason, I hope it’s not a total bust because schools and businesses are so reactive to the last event that I don’t want them to overcorrect the wrong way after all these early dismissals and closings. Then we get a slight risk in May and nobody does anything and there’s some bad results.

[TSSN+]

1 minute ago, WxUSAF said:

If for no other reason, I hope it’s not a total bust because schools and businesses were so reactive to the last event that I don’t want them to overcorrect the wrong way after all these early dismissals and closings. Then we get a slight risk in May and nobody does anything and there’s some bad results.

Not sure schools doing anything for a slight risk though. 

[SnowenOutThere]

Drove back to uva this morning. Really has that high end potential feel in those showers I drove through. Pouring rain. Anywho, during some time on route 29 could see the cloud deck breaking up with sky above. Now at uva and can just see the low level clouds racing by.