2024 Severe Weather General Discussion

[yoda]

ay 2 Convective Outlook  
   NWS Storm Prediction Center Norman OK
   0100 PM CDT Mon Apr 01 2024

   Valid 021200Z - 031200Z

   ...THERE IS A MODERATE RISK OF SEVERE THUNDERSTORMS ACROSS A LARGE
   PORTION OF OHIO...AND INCLUDING ADJACENT PARTS OF SOUTHEASTERN
   INDIANA...NORTHERN KENTUCKY...AND WESTERN WEST VIRGINIA...

   ...SUMMARY...
   A potentially substantial severe weather outbreak -- possibly
   including a few significant/long-track tornadoes -- is evident for
   Tuesday afternoon and evening, with highest probability centered
   over the Ohio vicinity, and extending southward across the Tennessee
   Valley.  Some severe risk exists as far south as the Gulf Coast, and
   as far east as western portions of Virginia and the Carolinas.

   ...Synopsis...
   While a positively tilted upper trough moves across the central
   third of the country Tuesday, a more compact/energetic short-wave
   feature is expected to dig aggressively/quickly southeastward across
   the Upper Midwest, gradually evolving into a closed low as it does. 
   By Wednesday morning, the deepening low is progged to reside over
   the Illinois vicinity.

   At the surface, a low initially over the Missouri vicinity is
   progged to deepen as the upper system digs southeastward, shifting
   northeastward across the Midwest through the day, and then occluding
   northward into Lower Michigan overnight.  A cold front associated
   with the low will sweep across the Mid Mississippi and Lower Ohio
   Valley through the day, and the Lower Mississippi/Tennessee/Upper
   Ohio Valleys overnight, crossing central/southern Appalachian Crest
   late.  Meanwhile, a warm sector should expand as far north and east
   as central and northeast Indiana/northern Ohio/western Pennsylvania,
   though limited in northward progress to West Virginia/northern
   Virginia/Maryland by persistent/slow-to-retreat cold-air damming
   over the Northeast.

   ...Ohio and Tennessee Valleys...
   Widespread thunderstorms -- including some degree of all-hazards
   severe risk -- will likely be spreading rapidly eastward across the
   Ohio Valley area at the start of the period.  This convection should
   reach the central Appalachians by late morning/midday, but -- though
   potentially having some impact on destabilization potential across
   the MDT and ENH risk areas -- should largely shift far enough east
   to allow warm-sector destabilization to commence.  

   As the surface low deepens and crosses Illinois and eventually moves
   into Indiana, and the cold front advances across the Mid Mississippi
   and Lower Ohio Valleys, storm redevelopment is expected to occur
   during the afternoon.  While evolution/storm mode remains somewhat
   difficult to discern -- in part due to earlier storms -- some mix of
   cellular and cluster/linear mode is expected to evolve.  Given the
   ample destabilization expected in combination with very
   strong/veering deep-layer flow, all-hazards severe potential is
   evident, including very large hail, strong/damaging winds, and
   several significant tornadoes.

   The greatest risk, which will include potential for a couple of
   intense/long-track tornadoes, should begin across Indiana, and the
   spread across Ohio through the afternoon and evening, potentially
   reaching as far east as western portions of West Virginia and far
   western Pennsylvania into the evening.  Eastward advance of the risk
   into central Pennsylvania will likely remain limited, but otherwise
   threat may spread into western portions of Virginia and the
   Carolinas late.

[Kmlwx]

Tracking galore to our west tomorrow. Beefy outlook. 

[Kmlwx]

The modeling is pretty much unanimous on us being wedged. Even NoVA doesn't look like it escapes the wedge for the most part. Will be keeping an eye on the elevated threat I guess!

[dailylurker]

1 hour ago, Kmlwx said:

The modeling is pretty much unanimous on us being wedged. Even NoVA doesn't look like it escapes the wedge for the most part. Will be keeping an eye on the elevated threat I guess!

Booo... I thought you meant we were all getting wedges, like EF5 lol

[Kmlwx]

I wills say - I know some of it is just weather superstition...but what Bob Chill says in winter applies sometimes in summer too. We tend to go on "heaters" of severe. A beefy event just to our west could be a harbinger of things to come. Maybe...And nobody come at me for "hoping" for destruction...I'm not. Weather gonna weather. 

[yoda]

Day 2 OTLK out... SLGT risk i95 and east... MGRL i81 to i95... 2/15/15... this is for Wednesday 

[yoda]

Morning AFD from LWX on the threats

couple of rounds of thunderstorms moves across the area this
afternoon and evening, and some of these are likely to be strong to
severe. In areas where the CAD remains the severe threat is going to
be from elevated storms producing hail. Model soundings indicate
around 1000-2000 J/kg of MUCAPE and strong shear will be present, so
some of these storms could produce large hail of 1 to 2". SPC has
the CAD area in a Marginal Risk for severe storms today.

The Slight Risk for severe storms has been expanded slightly
eastward along/south of I-66 to the Fredericksburg area, and extends
west along US-48 up through western MD. This is where storms pushing
in from the OH Valley will have the most favorable environment of
surface-based instability, strong shear, and large scale forcing for
ascent. Given the cold temperatures aloft and elevated instability
present, it is certainly possible a few supercells develop along the
I-64 corridor that are capable of producing hail of 2" or greater. A
tornado or two cannot be rule out, though that threat is confined to
the far southwestern CWA (peak threat around Highland County).

After the main severe threat window passes, expect a wet night as
widespread showers and scattered thunderstorms continue moving
across the area.

&&

.SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/...
The large cutoff low over the OH Valley slowly pivots eastward
toward the Mid-Atlantic. Strong forcing for ascent is going to be
present across the region, with widespread showers and embedded
thunderstorms ongoing sunrise Wednesday. As the morning progresses,
a wave of low pressure will cross east of the Blue Ridge, rapidly
deepening as it moves toward southern NJ. A broken line of showers
and thunderstorms is likely to develop along/east of US-15, then
rapidly push eastward across the area through Wednesday afternoon.
Even though instability is low, there will be an incredible amount
of shear as the triple point of the surface low crosses the area. In
addition to damaging winds, QLCS tornadoes will be a possibility.
SPC has upgraded parts of the area to a Slight Risk (level 2 of 5),
with a Marginal Risk (level 1 of 5) for most areas along and east of
the Blue Ridge.

[high risk]

Wednesday is pretty interesting.    The shear will be off of the charts, and wind damage and tornadoes seem possible in any sustained surfaced-based storms.      But how far north will the low-level warm air get?   Pretty good agreement it makes it into southern MD and also pretty good agreement that it doesn't make it north of the DC Beltway.   The in-between zone (including DC) has a fair amount of uncertainty.

[yoda]

12 minutes ago, high risk said:

Wednesday is pretty interesting.    The shear will be off of the charts, and wind damage and tornadoes seem possible in any sustained surfaced-based storms.      But how far north will the low-level warm air get?   Pretty good agreement it makes it into southern MD and also pretty good agreement that it doesn't make it north of the DC Beltway.   The in-between zone (including DC) has a fair amount of uncertainty.

When you say low-level warm air, is that related to or correlate with the warm front?  Or is it something different?

[Kmlwx]

24 minutes ago, high risk said:

Wednesday is pretty interesting.    The shear will be off of the charts, and wind damage and tornadoes seem possible in any sustained surfaced-based storms.      But how far north will the low-level warm air get?   Pretty good agreement it makes it into southern MD and also pretty good agreement that it doesn't make it north of the DC Beltway.   The in-between zone (including DC) has a fair amount of uncertainty.

I've mostly written off both days for MBY - hoping for the unicorn of elevated storms with some hail. HRRR looked pretty good honestly...but we know how that goes. 

Hoping for some better push of the warm air. But yes - it does't look great for DC northward. 

[yoda]

Updated morning AFD from LWX 

Area Forecast Discussion
National Weather Service Baltimore MD/Washington DC
1025 AM EDT Tue Apr 2 2024

.SYNOPSIS...
A frontal boundary lingers in the vicinity of the area through mid
week. Unsettled weather is expected as multiple rounds of showers
and thunderstorms impact the region. A series of cold fronts
sweep through the area Wednesday and Thursday bringing windy
conditions that last through the weekend. High pressure builds
overhead Sunday into early next week.

&&

.NEAR TERM /THROUGH TONIGHT/...
An initial round of showers and a few thunderstorms were
exiting NE MD as of mid morning. We are currently watching MCS
activity over the OH Valley that looks to move into the area
this afternoon. Near-surface stability will remain, but mid-
level lapse rates of 6-7 C/km will contribute to MUCAPE of
around 500 J/kg. This will result in a threat for isolated
thunder and possibly some spotty small hail if individual
updrafts are able to maintain enough persistent vigor and tap
into the increasing mid-level flow/shear. The severe weather
risk should remain very low until nightfall per latest
obs/trends, but may increase at least conditionally thereafter
as stronger height falls move in. In addition, instances of
flooding are appearing increasingly likely across the northern
half of the CWA as additional rounds of showers and
thunderstorms traverse increasingly saturated soils

[NorthArlington101]

HRRR has persistently had a solid cell tracking through Central VA this afternoon. Tough to believe while we’re sitting here stuck in the #wedge

[high risk]

2 hours ago, yoda said:

When you say low-level warm air, is that related to or correlate with the warm front?  Or is it something different?

     The surface warm front is the leading edge of that warmer air head trying to return to the north.

[George BM]

That line approaching Charleston, WV means business. It has a tornado warning box the size of some of the STW boxes we get here. Lots of kinks in the line.

[Eskimo Joe]

9 minutes ago, George BM said:

That line approaching Charleston, WV means business. It has a tornado warning box the size of some of the STW boxes we get here. Lots of kinks in the line.

NWS Charleston is getting multiple reports of tornadoes so they are just warning the entire line. Makes sense.

[Eskimo Joe]

 

 

 

[yoda]

3 minutes ago, Eskimo Joe said:

 

 

 

 

26 minutes ago, yoda said:

NWUS51 KRLX 021445
LSRRLX

Preliminary Local Storm Report
National Weather Service Charleston WV
1045 AM EDT Tue Apr 2 2024

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

1025 AM     Tstm Wnd Dmg     2 SW Westwood           38.46N 82.70W
04/02/2024                   Boyd               KY   Emergency Mngr

            Trailer overturned and houses nearby
            destroyed.

 

[yoda]

12z 3km NAM tries to blast through something fierce at 02z into DC metro area... not sure if it's a supercell or what 

[George BM]

10 minutes ago, yoda said:

12z 3km NAM tries to blast through something fierce at 02z into DC metro area... not sure if it's a supercell or what 

Verbatim... an elevated supercell/multicellular cluster w/ hail. Surface temps in the upper 40s locally at that time.

[Kmlwx]

Just now, George BM said:

Verbatim... probably an elevated supercell/multicellular cluster w/ hail. Surface temps in the upper 40s locally at that time.

UH swath on it weakens considerably as it approaches too - that could hint that it is weakening at the time. 

[yoda]

2 minutes ago, George BM said:

Verbatim... probably an elevated supercell/multicellular cluster w/ hail. Surface temps in the upper 40s locally at that time.

Could then mean a large hail producer 

[yoda]

RLX's (Charleston WV) new STW is pushing up against the LWX CWA in W VA...

[09-10 analogy]

Somewhat ironic, or eerie, or maybe just uselessly coincidental, that the overlay for the hatched 10% significant tornadoes today covers almost exactly the location of the vast majority of tornadoes of Superoutbreak I, whose 50th anniversary is tomorrow. 

[Rhino16]

Wonder if I get in on some of that WV line later…

[09-10 analogy]

47 minutes ago, Eskimo Joe said:

 

 

 

Per the MD 344, the extraordinary shear seems to be quite capably overcoming the lack of instability in WVA, so if that's occuring upstream of us ..?

[yoda]

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Baltimore MD/Washington DC
1209 PM EDT Tue Apr 2 2024

The National Weather Service in Sterling Virginia has issued a

* Severe Thunderstorm Warning for...
  Highland County in western Virginia...
  Pendleton County in eastern West Virginia...
  South central Grant County in eastern West Virginia...

* Until 115 PM EDT.

* At 1208 PM EDT, severe thunderstorms were located along a line
  extending from Stonewall Jackson to 8 miles west of Holly River
  State Park to near Leonard, moving east at 75 mph.

  HAZARD...60 mph wind gusts.

  SOURCE...Radar indicated.

  IMPACT...Damaging winds will cause some trees and large branches
           to fall. This could injure those outdoors, as well as
           damage homes and vehicles. Roadways may become blocked by
           downed trees. Localized power outages are possible.
           Unsecured light objects may become projectiles.

* Locations impacted include...
  Franklin, Monterey, Brandywine, Upper Tract, Doe Hill, Head Waters,
  Brushy Run, Bolar, Riverton, Deer Run, Liberty, Circleville,
  Ruddle, Williamsville, Oak Flat, Vanderpool, Sirons Mill, Hightown,
  Onego, and Clover Creek.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

For your protection move to an interior room on the lowest floor of a
building.

&&

LAT...LON 3836 7973 3862 7962 3866 7963 3867 7959
      3878 7951 3889 7952 3890 7945 3893 7945
      3892 7937 3896 7935 3877 7908 3850 7922
      3841 7932 3838 7931 3822 7944 3822 7948
      3818 7952 3822 7971 3827 7980 3831 7981
TIME...MOT...LOC 1608Z 279DEG 66KT 3898 8045 3865 8050 3817 8038

HAIL THREAT...RADAR INDICATED
MAX HAIL SIZE...<.75 IN
WIND THREAT...RADAR INDICATED
MAX WIND GUST...60 MPH

[konksw]

Gnarly looking line. 

[yoda]

Afternoon update (1730z OTLK) from SPC is late... wonder if the SLGT risk will be pulled back west some at all 

[Kmlwx]

1 minute ago, yoda said:

Afternoon update (1730z OTLK) from SPC is late... wonder if the SLGT risk will be pulled back west some at all 

Could also be late if they are devoting most of their attention to active severe threat(s) today. 

[Eskimo Joe]

One thing that could work in our favor for severe weather for tomorrow would be if a surface low pops on the lee of the mountains. The 00z/12z Euro, and to a lesser extent the 12z NAM, tries to show this tomorrow. That would aid the warm front in popping north and giving some better lift closer to DC and Baltimore. If this were May, I'd be more inclined to believe that, but right now I think that's a long shot. Looks like south of I-66 to east of US 50 are in a better position for some interesting weather tomorrow.