2019 Mid-Atlantic Severe Wx - General Discussion

[Kmlwx]

 SPC mesoanalysis has supercell composite parameter of 12 in a pocket over the area. 

[biodhokie]

Red Box nearby.

Mesoscale Discussion 0852
   NWS Storm Prediction Center Norman OK
   1202 PM CDT Tue May 28 2019

   Areas affected...portions of the Mid-Atlantic into the Northeast

   Concerning...Severe potential...Tornado Watch likely 

   Valid 281702Z - 281900Z

   Probability of Watch Issuance...95 percent

   SUMMARY...Storms are expected to develop this afternoon and will
   likely become severe. Large hail, damaging wind gusts, and a few
   tornadoes are possible. A tornado watch will likely be issued in the
   next couple of hours.

   DISCUSSION...A belt of enhanced mid-level westerly flow of 50-70
   knots is stretching across the Great Lakes into the
   Mid-Atlantic/Northeast. A shortwave trough embedded within this
   zonal flow currently entering the Great Lakes region will move
   eastward throughout the day helping to provide forcing for ascent
   and strengthen deep layer shear. A surface low is located just
   east-southeast of Buffalo, NY with a warm front stretching to the
   southeast through northeast PA and central NJ. This warm front
   should lift east-northeast with the surface low forecast to track
   generally eastward. The Cu field is becoming increasingly agitated
   within the warm sector and storms are likely to develop in the next
   couple of hours.

   Storms are likely to develop across west/central PA and move
   east-southeast during the afternoon and evening into portions of
   NJ/MD/DE/southern NY. Supercell development is likely and few storms
   may remain discrete. Low-level veering is better to south/east
   across the region, but flow/shear is stronger farther to the north.
   Large hail is possible given forecast MLCAPE of 1500-3000 J/kg and
   effective bulk shear of 35-50 knots. Additionally, strong synoptic
   winds and steepening low-level lapse rates, especially where strong
   insolation occurs, will increase the severe wind threat. Tornadoes
   are possible as well, especially for storms that exhibit more
   southeast movement, which will maximize SRH per observed/forecast
   soundings.

   ..Nauslar/Thompson.. 05/28/2019

   ...Please see www.spc.noaa.gov for graphic product...

   ATTN...WFO...OKX...PHI...BGM...AKQ...BUF...CTP...LWX...PBZ...
   CLE...

   LAT...LON   39767949 39848040 40378054 40878056 41458043 41818024
               42007982 42057791 41957629 41447465 41257439 40837422
               40457419 39887453 38977511 38587554 39077680 39307738
               39767949 

[Kmlwx]

Shocked that meso covers so far into Maryland. Includes Howard County entirely. 

[Kmlwx]

Worth noting the ARW and ARW2 are much more robust with storms (especially across northeastern parts of the CWA). 

I'm still on board for tomorrow. 

[H2O]

nothing south of the potomac.  Im out

[adelphi_sky]

54 minutes ago, Kmlwx said:

 SPC mesoanalysis has supercell composite parameter of 12 in a pocket over the area. 

Is 12 good or bad? 

[Kmlwx]

2 minutes ago, H2O said:

nothing south of the potomac.  Im out

I still think most of us are out

[Kmlwx]

Just now, adelphi_sky said:

Is 12 good or bad? 

It is quite high for this area. Doesn't mean much without forcing, though. 

[yoda]

10 minutes ago, Kmlwx said:

Shocked that meso covers so far into Maryland. Includes Howard County entirely. 

SLGT risk includes all of C and N MD on the 1630 OTLK... so that is probably why

[nj2va]

Full sun/clear skies here and currently 86.  Maybe a surprise storm or two this far south later. 

[Eskimo Joe]

$20 says they red box to the Potomac River.  We are PRIMED if something can fire on its own down here.

[Kmlwx]

9 minutes ago, Eskimo Joe said:

$20 says they red box to the Potomac River.  We are PRIMED if something can fire on its own down here.

Oh snap. 

 

ETA: I'd feel pretty good about my storm odds today if I was in Lancaster/Millersville this PM. 

[Eskimo Joe]

Upstream sounding from PIT...BOOM!

 

[yoda]

Just now, Eskimo Joe said:

Upstream sounding from PIT...BOOM!

 

Do you know if LWX is doing one?  Or since they are barely out of SLGT they will not do one? 

[Kmlwx]

So what happens when EJ is in and Kmlwx is out? The @WxWatcher007 scale is broken now. 

[Eskimo Joe]

2 minutes ago, yoda said:

Do you know if LWX is doing one?  Or since they are barely out of SLGT they will not do one? 

Doubt it.  They usually tweet about it, haven't seen anything on their social media.

[Eskimo Joe]

Just now, Kmlwx said:

So what happens when EJ is in and Kmlwx is out? The @WxWatcher007 is broken now. 

I'm in for a big cell or two and that's it, but if you get under one good luck.  Going to be a few happy campers and many people left out.

[yoda]

1 minute ago, Kmlwx said:

So what happens when EJ is out and Kmlwx is in? The @WxWatcher007 is broken now. 

Appears you have made a good call about tomorrow... entire LWX CWA included in SLGT risk in 1730 SPC OTLK... ENH risk for all of S PA and all of MD and N VA and DC

[biodhokie]

Just now, Kmlwx said:

So what happens when EJ is in and Kmlwx is out? The @WxWatcher007 is broken now. 

IIRC it defaults down to the lowest person who is out. So we are currently under a code Yoda.

[Eskimo Joe]

Just now, yoda said:

Appears you have made a good call about tomorrow... entire LWX CWA included in SLGT risk in 1730 SPC OTLK... ENH risk for all of S PA and all of MD and N VA and DC

I'm in for now.  Going to wait until late tomorrow morning before going all in or not.

[Kmlwx]

Just now, yoda said:

Appears you have made a good call about tomorrow... entire LWX CWA included in SLGT risk in 1730 SPC OTLK... ENH risk for all of S PA and all of MD and N VA and DC

Even Thursday is looking decent on recent sim reflectivity. But I think tomorrow might be the main show. Lots of ENH this year so far. This year has been fun so far...loved the Saturday storms in Columbia. 

[yoda]

Woah... 1730 SPC discussion is

...Ohio Valley through the Middle Atlantic region...

   South of the stationary front, the atmosphere across much of the OH
   Valley into the Middle Atlantic will once again become moderately
   unstable with 1500-2500 J/kg MLCAPE expected. Some storms may be
   ongoing over portions of the warm sector, posing at least a marginal
   threat for damaging wind and hail. As the boundary layer
   destabilizes, storms will increase in intensity during the day. Much
   of this region will reside within belt of moderate westerlies with
   40-50 kt unidirectional bulk shear supportive or organized storm
   structures including supercells and bowing segments. Damaging wind
   and large hail will be the main threats as storms spread east
   through the warm sector during the day. While a few tornadoes will
   be possible, especially with discrete supercell structures, the
   unidirectional nature of the low-level wind profiles will limit size
   of 0-1 km hodographs and a more widespread tornado threat.

[Kmlwx]

Just now, Eskimo Joe said:

I'm in for now.  Going to wait until late tomorrow morning before going all in or not.

I think at the very least storms should be more widespread than today. Intensity TBD...but it still looks like enough fuel and shear will be around. Nice stretch we've had for parts of the area. Wish I had been at my apartment for the Columbia TOR. 

[Itstrainingtime]

11 minutes ago, Kmlwx said:

Oh snap. 

 

ETA: I'd feel pretty good about my storm odds today if I was in Lancaster/Millersville this PM. 

I am squarely between those 2 locations and don't feel good about it at all, lol

[Kmlwx]

Just now, yoda said:

Woah... 1730 SPC discussion is

 

Seems fairly standard - I guess the comment at the end is unusual - but they are saying they don't think we will achieve that given the unidirectional wind. 

[Eskimo Joe]

Just now, yoda said:

Woah... 1730 SPC discussion is

 

Yea it's nice.  We'll have a kicked plus the airmass.

Quote

 ...Ohio Valley through the Middle Atlantic region...

   South of the stationary front, the atmosphere across much of the OH
   Valley into the Middle Atlantic will once again become moderately
   unstable with 1500-2500 J/kg MLCAPE expected. Some storms may be
   ongoing over portions of the warm sector, posing at least a marginal
   threat for damaging wind and hail. As the boundary layer
   destabilizes, storms will increase in intensity during the day. Much
   of this region will reside within belt of moderate westerlies with
   40-50 kt unidirectional bulk shear supportive or organized storm
   structures including supercells and bowing segments. Damaging wind
   and large hail will be the main threats as storms spread east
   through the warm sector during the day. While a few tornadoes will
   be possible, especially with discrete supercell structures, the
   unidirectional nature of the low-level wind profiles will limit size
   of 0-1 km hodographs and a more widespread tornado threat.

   ...MAXIMUM RISK BY HAZARD...
   Tornado:   5%     - Slight
   Wind:     30% SIG - Enhanced
   Hail:     30%     - Enhanced

   ..Dial.. 05/28/2019

 

[Kmlwx]

Just now, Itstrainingtime said:

I am squarely between those 2 locations and don't feel good about it at all, lol

You're closer to the forcing and multiple models carry some sort of cells or complex through your area. SEPA has a little mini tornado allery IIRC. 

[yoda]

Tornado Watch issued to our north... no LWX counties in it... 50/20 probs on TOR

[Itstrainingtime]

Just now, Kmlwx said:

You're closer to the forcing and multiple models carry some sort of cells or complex through your area. SEPA has a little mini tornado allery IIRC. 

Yes, we do...which is precisely why I'm NOT feeling good. (as in...I really don't want this to happen) 

[Kmlwx]

Just now, Eskimo Joe said:

Yea it's nice.  We'll have a kicked plus the airmass.

 

Wonder if the usual spots (around Potomac etc) where winds sometimes get a little more backed due to local factors could enhance a tor threat. 

Either that or perhaps some factor that could back the winds a bit more isn't being seen yet. Nonetheless, I like the sounds of a day 2 ENH with decent discussion wording.