2022 Mid-Atlantic Severe Wx Thread (General Discussion Etc)

[hstorm]

On 7/9/2022 at 2:58 PM, batmanbrad said:

Yes, Andy "Woody!" Woodcock, he was a trip.  I occasionally go to other WFO's to check out their AFD's - some can get very wordy/technical, I especially remember the Taunton (now Boston/Norton) office when there would be a coastal storm in winter or a tropical system in summer, the discussion was a bit like "War and Peace"!

Growing up in southeastern New England, Walt Drag's AFDs from Taunton were always a great and informative read in advance of any coming storm.

[high risk]

6 hours ago, yoda said:

Looks like Tuesday afternoon may be our last chance for some storms or even severe storms for the next 10 days or so -- from this afternoon's AFD:

 

With southerly flow and moisture return ahead of a cold front
Tuesday, temperatures will soar toward the low 90s for most
locales. PWs will increase through the day to near 1.75-2" east
of I-81 by the evening. Profiles show a decent overlap of CAPE
in the -10 to -20C layer on soundings, so there could be a large
hail threat in combination with a damaging wind threat in any
thunderstorm. There could be two rounds of thunderstorms: 1)
Along a lee-side pressure trough near and east of the Blue Ridge
and 2) With the frontal boundary itself. There is also
noteworthy shear for this time of year (40-50 kts of bulk
shear).

      I will cautiously share some of LWX's optimism, as I kind of like what I'm seeing on the CAMs (I'll ignore the NAM Nest Howard County split....) in terms of storms forming along what appears to be the lee trough in the late afternoon Tuesday in an environment with with good instability and shear.

 

[yoda]

I wasn't really counting on a tornado threat tomorrow... but LWX has it in their afternoon AFD 

SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
A cold front will approach from the Great Lakes region Tuesday.
A low pressure trough of low pressure should set up on the
leeside of the mountains late Tuesday morning and into the
afternoon. Winds will increase out of the south to south-
southwest, leading to increasing warmth and humidity where
temperatures will climb into the 90s with dewpoint temperatures
punching into the lower to middle 70s. This will be the fuel for
the thunder that is expected Tuesday afternoon and evening as
the cold front approaches the region. CAPE values will rise into
the 1500 to 2000 J/kg range. The combination of this CAPE and
some added wind shear as mid-level energy sweeps in from the
northwest will get developing thunderstorms to possibly become
severe Tuesday afternoon and evening. Thunderstorms will be
capable of producing any one of the severe weather aspects such
as flooding downpours, damaging wind gusts, large hail, and
tornadoes. SPC has the northeastern one-third of our region in
the Slight Risk for severe thunderstorms Tuesday and Tuesday
night. Depending on additional model data late this afternoon
and this evening, this area may be brought farther south and
east into eastern Virginia and parts of southern Maryland. The
timing on any severe thunderstorms on Tuesday will be from mid-
afternoon through early evening, especially for the metro areas.
The actual cold front should pass through the region later
Tuesday night, perhaps an hour or two before daybreak on
Wednesday. Afterwards, the front could stall near the Virginia
and North Carolina border on Wednesday.

[high risk]

1 hour ago, yoda said:

I wasn't really counting on a tornado threat tomorrow... but LWX has it in their afternoon AFD 

SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
A cold front will approach from the Great Lakes region Tuesday.
A low pressure trough of low pressure should set up on the
leeside of the mountains late Tuesday morning and into the
afternoon. Winds will increase out of the south to south-
southwest, leading to increasing warmth and humidity where
temperatures will climb into the 90s with dewpoint temperatures
punching into the lower to middle 70s. This will be the fuel for
the thunder that is expected Tuesday afternoon and evening as
the cold front approaches the region. CAPE values will rise into
the 1500 to 2000 J/kg range. The combination of this CAPE and
some added wind shear as mid-level energy sweeps in from the
northwest will get developing thunderstorms to possibly become
severe Tuesday afternoon and evening. Thunderstorms will be
capable of producing any one of the severe weather aspects such
as flooding downpours, damaging wind gusts, large hail, and
tornadoes. SPC has the northeastern one-third of our region in
the Slight Risk for severe thunderstorms Tuesday and Tuesday
night. Depending on additional model data late this afternoon
and this evening, this area may be brought farther south and
east into eastern Virginia and parts of southern Maryland. The
timing on any severe thunderstorms on Tuesday will be from mid-
afternoon through early evening, especially for the metro areas.
The actual cold front should pass through the region later
Tuesday night, perhaps an hour or two before daybreak on
Wednesday. Afterwards, the front could stall near the Virginia
and North Carolina border on Wednesday.

           As I said yesterday, I like tomorrow, especially for central MD.      We'll have good timing, moderate forcing, moderate instability, and decent deep layer shear.     The tornado threat isn't huge, but the forecast soundings do show some turning of direction in the lower-levels, so I would agree that a tornado or two can't be ruled out.

[high risk]

  Things continue to look active for the late afternoon / early evening period.    SPC has added an ENH to the DC-Baltimore corridor.

[Kmlwx]

6 minutes ago, high risk said:

  Things continue to look active for the late afternoon / early evening period.    SPC has added an ENH to the DC-Baltimore corridor.

Just saw the upgrade to enhanced. Day-of upgrades always seem to bode well for us. Especially when the upgrade is at the 1300 update or later. Let's go! 

[Kmlwx]

Also - one of the few recent times I can remember when we have no cloud worries early on. 

[WxUSAF]

12 minutes ago, high risk said:

  Things continue to look active for the late afternoon / early evening period.    SPC has added an ENH to the DC-Baltimore corridor.

Storms after 430pm please when my flight leaves BWI

[Kmlwx]

HREF looks decent. 

[thunderbolt]

38 minutes ago, high risk said:

  Things continue to look active for the late afternoon / early evening period.    SPC has added an ENH to the DC-Baltimore corridor.

[Kmlwx]

It kind of looks like the eggplant emoji shape....

[WxWatcher007]

 

[high risk]

45 minutes ago, WxUSAF said:

Storms after 430pm please when my flight leaves BWI

       As long as ongoing convection to the northwest hasn't screwed up the schedule at BWI, and no other delays occur, you *should* be ok, as no guidance has storms arriving at BWI that early.

[AmericanWxFreak]

Ends up splitting Central MD but sends quite the bow thru NOVA

[mattie g]

35 minutes ago, WxWatcher007 said:

 

I'm always dubious of being on the SW edge of any outlook category.

[BlizzardNole]

16 minutes ago, AmericanWxFreak said:

Ends up splitting Central MD but sends quite the bow thru NOVA

 

Smart model

[AmericanWxFreak]

I don't think I have ever seen you guys use this for severe, but it looks like a good time later so I like it and am expecting it to be right - RGEM lol

 

[Kmlwx]

4 minutes ago, AmericanWxFreak said:

I don't think I have ever seen you guys use this for severe, but it looks like a good time later so I like it and am expecting it to be right - RGEM lol

 

 

HRDPS

[AmericanWxFreak]

4 minutes ago, Kmlwx said:

HRDPS

I knew that. Doh. Seems to be pretty good agreement on 00z arrival 

 

[Kmlwx]

It seems like we have not terrible mid-level lapse rates for a change. However, those may not be timed right with the actual storms - seems the best MLLR will be heading out of the area by the time storms are firing/ongoing. But better than nothing I suppose. I think we have a better than usual shot at a more widespread event today...hence the SPC ENH risk upgrade. 1630z discussion will be interesting to get a read on the latest thoughts. 

[Kmlwx]

1 minute ago, AmericanWxFreak said:

I knew that. Doh. Seems to be pretty good agreement on 00z arrival 

Agreed. Though these things do sometimes like to be a BIT ahead of schedule (sometimes way ahead). I guess a lot will depend on whether it's one of those days where the slightest trigger makes for a messy radar. So far plenty of sun and no signs of storms yet. My dewpoint is around 70 so that can't hurt. I'll be watching that 3-4pm timeframe to see where we stand. 

[Kmlwx]

First mesoscale discussion of the day north of the Mason-Dixon line all the way up into the NE. 

[AmericanWxFreak]

ooooo I enjoy intense lines

.NEAR TERM /THROUGH TONIGHT/...
A lot of sunshine as of 1030am from just west of I-81 and east
to the Chesapeake Bay. This will obviously ramp up our
temperatures quickly into the lower 90s and our dewpoint
temperatures to near 70s by the middle part of this afternoon. A
low pressure trough is in place parallel to I-81 with a surface
cold front sagging across eastern Ohio and western Pennsylvania.
The combination of these two features, along with a mid-level
trough and a right entrance jet max sagging into the CWA will
allow for numerous thunderstorms, some severe, to develop and
possibly forming an intense line around mid-afternoon into this
evening. Both MLCAPE and MUCAPE is expected to approach 2000 to
2500 J/kg. 0-3km wind shear will be 15 to 20 knots easily in
most places. The main threats will be damaging winds and
isolated tornadoes. Large hail and flooding rainfall is also a
distinct possibility. SPC has Northeast MD and northeastern VA
in an Enhanced Risk for severe thunderstorms. WPC has the heart
of our CWA in a Marginal Risk for Excessive Rainfall that could
lead to Flash Flooding. Timing on supercells or a line of
intense thunderstorms reaching the metro areas would be 4pm to
8pm. Much of this activity will reach southern Maryland closer
to 8pm to 10pm. Nonetheless, it looks like a busy and stormy
day.

[H2O]

Will this hype day deliver?

[aldie 22]

20 minutes ago, H2O said:

Will this hype day deliver?

I can't wait for Ian to come in later and say how the region is capped and that's why severe never happened. Wait....who's Ian?

[mattie g]

40 minutes ago, H2O said:

Will this hype day deliver?

SW edge of the outlook category = not meeting the hype

[North Balti Zen]

47 minutes ago, H2O said:

Will this hype day deliver?

no?

I love being in the middle of ENH and then a million posts showing models with storms forming nowhere near northern balt county. 

[mappy]

Hey friends, do you know timing? I haven’t looked at models but need to let Mr Map know as we’ve got landscaping work going on at home. Good luck today, I’m rooting for ya from the west coast! 

[AmericanWxFreak]

5 minutes ago, mappy said:

Hey friends, do you know timing? I haven’t looked at models but need to let Mr Map know as we’ve got landscaping work going on at home. Good luck today, I’m rooting for ya from the west coast! 

Looks like 23z-1z time frame is most likely. 

[mappy]

11 minutes ago, AmericanWxFreak said:

Looks like 23z-1z time frame is most likely. 

Thank you!