2023 Mid-Atlantic Severe Wx Thread (General Discussion)

[WxWatcher007]

35 minutes ago, CAPE said:

Awesome pics

[Chinook]

1 hour ago, WxSynopsisDavid said:

Absolute textbook of an embedded hook echo. Very rare to see this signature in the northeast.

Was that Upper Freehold, Pennsylvania? I'm not familiar with where this tornado warning took place.

[WxSynopsisDavid]

4 minutes ago, Chinook said:

Was that Upper Freehold, Pennsylvania? I'm not familiar with where this tornado warning took place.

New Jersey

[yoda]

18z GFS has some interesting soundings just south of DCA at 21z Wednesday 

[Kmlwx]

58 minutes ago, yoda said:

18z GFS has some interesting soundings just south of DCA at 21z Wednesday 

Nice to track actual weather instead of phantom 10 day snowstorms.... 

[WxUSAF]

Our basketball hoop blew over. That’s never happened before and we’ve had some strong winds. Luckily it rotated a bit first or it would have smashed into my car.

[WxWatcher007]

 

[WxUSAF]

Confirmed EF1 in Cecil county

 

[NorthArlington101]

Delaware tornado was an EF3.

[Kmlwx]

Powerful for this part of the country. Decent track length as well!

[Kmlwx]

The NAM (yes the NAM at range) has been a bit more favorable for severe Thursday. Biggest issue I think has been that the timing has been off for us. I think for the severe weenies in the area, the most exciting scenario would be for the system to slow enough that it allows a frontal passage during peak heating Thursday. Prior runs of the globals had the timing at poor parts of the diurnal cycle. The other thing would be if it sped up enough to get us with Wednesday - but the Wed threat seems focused well to the north and/or west. 

[North Balti Zen]

SPC gives it some credence with a day 3 MGL

 

[yoda]

Discussion was pretty decent as well

Day 3 Convective Outlook  
   NWS Storm Prediction Center Norman OK
   0229 AM CDT Tue Apr 04 2023

   Valid 061200Z - 071200Z

   ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS THURSDAY ACROSS
   PARTS OF THE MID ATLANTIC AND DEEP SOUTH TEXAS...

   ...SUMMARY...
   Strong thunderstorms posing at least some risk for severe weather
   are possible across parts of the Mid Atlantic and Deep South Texas
   Thursday.

   ...Synopsis...
   Within the main branch of split westerlies emanating from the
   Pacific, models indicate that a broad, occluded cyclone, initially
   centered near James Bay, will continue to weaken during this period.
   Renewed cyclogenesis may occur farther east, across northern Quebec
   through Newfoundland and Labrador, but it appears that this will
   remain modest in strength.  

   The associated cold front trailing to the south is forecast to
   advance from the upper Ohio Valley and lee of the lower Great Lakes
   across much of the northern into middle Atlantic by late Thursday
   night, as the remnant mid-level troughing accelerates eastward and
   suppresses mid-level short wave ridging initially building across
   New England and the Canadian Maritimes.

   In lower latitudes, prominent mid-level ridging appears likely to be
   maintained, centered over the southeastern Gulf of Mexico and
   Florida Peninsula, and a considerable influence across much of the
   Southeast.  Beneath its northwestern periphery, the trailing flank
   of the cold front is expected to weaken while slowly advancing
   across the northwestern Gulf coast vicinity.  However, seasonably
   moist return flow will persist along/above it, downstream of low
   amplitude mid-level troughing across the subtropical eastern Pacific
   into the northern Mexican Plateau.

   ...Mid Atlantic...
   Preceding the cold front, models continue indicate that low-level
   moisture return coupled with daytime heating will support modest
   destabilization east of the Allegheny Mountains by Thursday
   afternoon.  Scattered storms probably will initiate along the higher
   terrain, with at least deep-layer shear conducive to supercells
   structures posing a risk for severe wind and hail.  Tornado
   potential remains a bit more uncertain.

   Storms are likely to gradually spread off the higher terrain with
   the mid-level height falls, and they could eventually consolidate
   into an organizing line or cluster overspreading coastal areas with
   potential for damaging wind gusts.

   It does not appear out of the question that severe weather
   probabilties could be increased further in later outlooks for this
   period.

[Kmlwx]

My early looks at Thursday are mixed. I do see the 6z Euro on the lightning density product spits out good storms for most of the area - timing looks decent as they come through after 18z through the end of the day. GFS seems less enthused with having good CAPE to work with. FWIW - CIPS is completely uninterested in the event. 

Definitely a Thursday situation at this point - I've written off Wednesday for most of us unless you're way out in the mountains to the west. 

[Kmlwx]

NAM nest (at range) blows up a pretty solid looking complex of storms for the metro areas Thur PM.

[Eskimo Joe]

1 hour ago, Kmlwx said:

NAM nest (at range) blows up a pretty solid looking complex of storms for the metro areas Thur PM.

I'm flying to Oklahoma very early Thursday. Expect this to be a major outbreak.

[Kmlwx]

Perhaps there needs to be an additional criteria added. "If ____ is out of town for event, automatic upgrade to that tier"  

[Kmlwx]

FV3 Hi-res at range shows stuff developing Thur PM but mainly for I-95 and east. 

[yoda]

Afternoon AFD from LWX sounds interesting 

SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/...
A lead wave ahead of a frontal system over the Ohio River Valley
will approach the area late Wednesday. Ridging will crest over
the area before heights begin to fall by Wednesday night. Given
the increasingly warm and unstable airmass, as well as some
added lift from terrain and the approach system to the west, a
few thunderstorms could develop mainly west of the Blue Ridge
late Wednesday afternoon into Wednesday night. Sufficient shear
will be present for storm organization, so a couple of strong to
severe thunderstorms can`t be ruled out.

The frontal system is set to cross the region on Thursday.
Cooling air moving in aloft above unseasonably warm and moist
air near the surface will likely result in moderate instability.
This coupled with moderately strong shear and forcing along the
approaching front should result in widespread showers and
thunderstorms, some of which could become capable of producing
severe weather in the form of damaging wind gusts and large
hail. Tornado potential is a bit more uncertain given relatively
weaker flow closer to the surface, but there is enough shear for
supercells. Also, any boundary interactions (terrain/bay/river
breeze circulations) could enhance this activity.

Temperatures will be very warm with highs well into the 80s and
lows in the 60s to around 70 east of the mountains Wednesday
into Thursday, 20 to 30 degrees above normal and more akin to
summer than spring. Temperatures will take a tumble Thursday
night behind the front.

[Eskimo Joe]

Just want to say that SPC has really upped their game in recent years. They were already solid, but man when they issue a Tornado Watch does it verify solidly in these parts.

[MN Transplant]

Some UH swaths across DC on the 12z NAM Nest

[yoda]

14 minutes ago, MN Transplant said:

Some UH swaths across DC on the 12z NAM Nest

Right at peak time for severe... 19z to 21z

[yoda]

Also interesting are the soundings for the area today... especially north and west of DC on the 12z NAM Nest and 12z NAM 

[midatlanticweather]

 

[Eskimo Joe]

Enjoy your outbreak tomorrow. From a WPC met on Twitter. 

 

[yoda]

Afternoon AFD from LWX for tomorrow's threat

SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
A cold front will cross the Appalachians Thursday morning, then
slowly press east through the day. Summer-like heat and humidity
will result in building instability ahead of the front. Convergence
along the boundary and height falls aloft signal a potential for
widespread shower and thunderstorm activity, and moderately strong
deep-layer shear will likely tend to organize any convection
that develops. Although the shear is favorable for supercells,
the shear vector and storm motions may tend to align parallel to
the approaching front; this suggests a more linear storm mode.
Should more discrete activity persist, there may be a more
substantial hail and wind risk, perhaps even a conditional
tornado threat near/east of I-95 where flow will be back due to
a bay/river breeze. Otherwise, gusty to locally damaging wind
gusts would be the primary threat. There is uncertainty in the
extent of instability - morning cloud cover could temper this -
but overall the relatively higher chances for strong to severe
thunderstorms appear to be between noon and 5pm south of I-70
and east of the Blue Ridge Mountains.

The front will slowly push offshore through the end of the week.
Dry air will gradually work into the region, but lingering
moisture and mid/upper jet forcing may lead to lingering showers
especially across central VA to southern MD.

[mappy]

woo storms!

[H2O]

My dream to chase recklessly, zero meter a TOR, get rolled and arrogantly brag has been destroyed. 
 

So I’m just gonna sofa chase any storms today. 

[Kmlwx]

Decent amount of guidance seems to favor exactly where SPC has the higher probs. Still, see a few models that get DC with good activity. We'll see. Definitely not the @Eskimo Joe outbreak. 

[WxWatcher007]

Slight risk?