2021 Mid-Atlantic Severe Weather - General Discussion

[WxUSAF]

HoCo pulled a DC today 

[Eskimo Joe]

Watch box is out: https://www.spc.noaa.gov/products/watch/ww0235.html

[Eskimo Joe]

Main cell just south of Mt. Vernon getting a decent hail signature on it. Dover and ADW radar starting to pick up on it.

[vastateofmind]

42 minutes ago, Eskimo Joe said:

Main cell just south of Mt. Vernon getting a decent hail signature on it. Dover and ADW radar starting to pick up on it.

I was at that location under that cell...didn't see/hear hail, but the rain was the heaviest we've had in a number of years, enough that I couldn't see houses on other side of cul de sac for about five minutes.

[A777]

for yesterday

[mattie g]

7 hours ago, NorthArlington101 said:

Warned the northern part of the storm too... pretty pathetic warning IMO. Can't find a pixel with a >30mph wind reading on RadarScope. 

Wife said it pounded for about 10 minutes.

[Kmlwx]

I'm not seeing much of anything to get super excited about severe weather wise. Other than general thunderstorms it looks like nothing big is on the horizon. 

[Eskimo Joe]

18 hours ago, Kmlwx said:

I'm not seeing much of anything to get super excited about severe weather wise. Other than general thunderstorms it looks like nothing big is on the horizon. 

It's probably over for us until tropical season. We're in the summer doldrums.

[Kmlwx]

53 minutes ago, Eskimo Joe said:

It's probably over for us until tropical season. We're in the summer doldrums.

We need to hope for a ring of fire style ridge. I had some nice rumbles on thunder last night. It's been a pretty "odd" spring IMO. But maybe the combination of still coming out of the COVID funk and the cicadas have thrown me off. Other than a few isolated spots - this has been a pretty low-key severe season. 

[mappy]

storms today? mr map had to go out of town for a few days to visit his ailing father. kiddo wants to swim later... 

[AdamHLG]

2 hours ago, Kmlwx said:

We need to hope for a ring of fire style ridge. I had some nice rumbles on thunder last night. It's been a pretty "odd" spring IMO. But maybe the combination of still coming out of the COVID funk and the cicadas have thrown me off. Other than a few isolated spots - this has been a pretty low-key severe season. 

There are so many damn cicadas flying around that in has caused convection inhibition.   

[mappy]

58 minutes ago, mappy said:

storms today? mr map had to go out of town for a few days to visit his ailing father. kiddo wants to swim later... 

yup. thunder in the distance

[Rhino16]

Storms firing up nearby, some crawling very slowly towards my location, some sun peaking out, hopefully it rains. 83°F

[yoda]

On 6/8/2021 at 3:16 PM, Kmlwx said:

I'm not seeing much of anything to get super excited about severe weather wise. Other than general thunderstorms it looks like nothing big is on the horizon. 

Afternoon LWX AFD says Monday maybe...

There continues to be some
disagreement in the ensembles on timing and intensity of any precip
and convection possible for the day on Monday. GEFS has a mean of
800 j/kg of CAPE with some members as high as 2500+ j/kg. Shear
looks to be a bit high with around 40 to 50 knots. This will need to
be monitored as we get closer to the event as some models suggest a
drier solution for the time period. A secondary front will pass
through Monday night and bring another round of showers, not really
expected much in terms of convection given the nocturnal passage. A
few uncertainties remain for the extended period with timing and
intensity of impacts but will continue to monitor as we get closer
to the events.

[csnavywx]

Don't sleep on the Monday shortwave. A compact, digging shortwave embedded in NW flow aloft possibly intercepting a plume of moisture and instability fed in ahead of the wave. One of the major questions is timing. A bit earlier and this could easily cause some significant trouble, given the progged shear and instability values progged on the NAM (and trending on the GFS).

[Kmlwx]

33 minutes ago, csnavywx said:

Don't sleep on the Monday shortwave. A compact, digging shortwave embedded in NW flow aloft possibly intercepting a plume of moisture and instability fed in ahead of the wave. One of the major questions is timing. A bit earlier and this could easily cause some significant trouble, given the progged shear and instability values progged on the NAM (and trending on the GFS).

I'd like to throw all my eggs in this basket! 

[George BM]

There's a SLGT risk for severe wind along and west of the blue ridge mountains where instability is most likely to be highest (MLCAPE  >1000J/kg) along with modest bulk shear. Areas immediately west of I-95 are in a MRGL risk.

[high risk]

Two upcoming chances, but the timing looks off on both of them for most of us.    The timing and coverage of late Sunday storms has a lot of spread in the guidance, but the best chances for SVR certainly do seem to be northwest of DC.      The Monday system right now looks more impressive, as noted in previous posts, but it too may be arriving a few hours too late.

[yoda]

3 hours ago, high risk said:

Two upcoming chances, but the timing looks off on both of them for most of us.    The timing and coverage of late Sunday storms has a lot of spread in the guidance, but the best chances for SVR certainly do seem to be northwest of DC.      The Monday system right now looks more impressive, as noted in previous posts, but it too may be arriving a few hours too late.

LWX AFD from last evening mentioned Monday and talked it up some

A potent trough will dive southward toward the region on Monday,
along with a reinforcing cold front. Flow aloft will rapidly
strengthen through the day, with 50-65 knots of effective bulk
shear present by the afternoon into the evening. Models differ
with respect to how much instability builds across the area, but
have been trending upward over the past day. There are also
questions regarding the areal coverage of storms across the
area, as well as the convective mode of any storms that do form.
However, if storms ultimately do form, and the instability
values are as advertised in models such as the NAM and Canadian,
a more significant severe weather event than the one on Sunday
could materialize. Depending on how storms evolve, a severe
thunderstorm threat could potentially linger into the first half
of the overnight hours. Confidence in nearly all aspects of the
forecast Monday remains very low, so we`ll continue to refine
our forecast as we move closer to the event.

[yoda]

Severe wording in all of the zones for this afternoon and evening 

[yoda]

Morning AFD from LWX about today and tomorrow severe threat 

Quote

For today, southwesterly flow will redevelop as the cold front
to the northwest approaches. This should nudge the stalled front
in our vicinity back to the northeast, bringing warmer and more
humid air across most of the CWA. Far eastern areas may stay
cooler and more stable, but certainly the entire area looks
warmer than yesterday. Some sun will be present through midday
at least in much of the area, but if not before then, shortly
thereafter storms will start to fire to the northwest, closer to
the front. There is some copious shear present, 30-40 knots, and
decent enough CAPE, 1000-2000 J/kg, so these factors suggest we
will have one or two squall lines, likely starting out as
clusters before evolving into lines, moving southeastward across
the region. The cooler, more stable air mass in our far eastern
areas, near the bay, may keep severe weather risk at bay, but
further west, a slight risk is now out for parts of western
MD/eastern WV and northwestern VA. Main risk appears to be
damaging winds, but a small hail risk appears present as well.
There is a marginal flood risk as well, mainly due to atecedent
conditions, but expectations of progressive storm movement
suggest it is a more marginal flood risk. Highs will be well
into the 80s today.

Showers likely linger for some time this evening, though the
thunder coverage should diminish, as the cold front gets hung up
near our area. Lows falling back into the 60s.

&&

.SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/...
Cold front number one will be stalled in our general vicinity at
the start of Monday. This will keep clouds and spotty showers
around, and by afternoon, areas southeast of front 1 could start
to see new thunderstorms form... this should be mainly close to
the bay. By then, however, next front approaching from the
northwest will start to approach, with new storms firing to our
northwest with it. Monday will be the warmest day with westerly
flow, sending highs well into the 80s. By night, showers and
storms with front 2 will overspread much of the area as front 1
finally gets kicked out. This second system also has a severe
weather risk, but it is a bit more uncertain, so its considered
marginal at this time. Shear will be excessive, possibly well
over 40 knots, but CAPE is uncertain. If it coincides, severe
weather coverage and intensity Monday evening could be in
excess of today/tonight.

[yoda]

06z NAM soundings suggest we could be rocking and rolling at both 00z and 03z Tuesday - for the late Monday threat 

[George BM]

17 minutes ago, yoda said:

06z NAM soundings suggest we could be rocking and rolling at both 00z and 03z Tuesday - for the late Monday threat 

If we can get the tongue of higher CAPE that some CAMs are hinting at to stay over our region tomorrow instead of being shunted further east, then I'd think that we could see some interesting storm modes (splitting supercells?) given the long straight hodographs.

[midatlanticweather]

That cluster in Pennsylvania is interesting. We will see how all this pans out today, but it has my interest. 

[Kmlwx]

Next couple of days could be interesting. We'll see. Only thing we've got to track for now. 

[Kmlwx]

HRDPS loves tomorrow at least based on the precip panels. 

[George BM]

41 minutes ago, midatlanticweather said:

That cluster in Pennsylvania is interesting. We will see how all this pans out today, but it has my interest. 

My current thinking, looking at more sufficient CAPE still being to the west atm, is that it will (if not die out) at least dwindle to some midday/early afternoon showers for this area with additional convection developing further upstream. That potential additional convection would probably be our best shot... at least for western zones (your place and westwards) where conditions are most favorable for stronger storms. Some storms could certainly slip further east into the metros but CAPE would be dwindling as they do leading to a weakening trend.

But yes. That current cluster is interesting looking indeed.

[Kmlwx]

28 minutes ago, George BM said:

My current thinking, looking at more sufficient CAPE still being to the west atm, is that it will (if not die out) at least dwindle to some midday/early afternoon showers for this area with additional convection developing further upstream. That potential additional convection would probably be our best shot... at least for western zones (your place and westwards) where conditions are most favorable for stronger storms. Some storms could certainly slip further east into the metros but CAPE would be dwindling as they do leading to a weakening trend.

But yes. That current cluster is interesting looking indeed.

It's also possible that current complex of storms could lay down some boundaries to focus later activity - again - most likely west of the most populated areas. 

[RIC_WX]

The line of storms rolling through Deep Creek is legit.  Let's see if they hold together crossing these hills.

[Kmlwx]

CIPS for the 36hr mark (on the 12z run coming out now) is fairly bullish. Jun 2, 1998 is on the analogs lol