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


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That escalated quickly

@high risk @Kmlwx @Eskimo Joe

Area Forecast Discussion
National Weather Service Baltimore MD/Washington DC
1035 PM EDT Wed Mar 30 2022

.SYNOPSIS...
A strong area of low pressure will move from the Mississippi River
Valley to the Great Lakes through Thursday. A warm front associated
with the low will lift northward through early Thursday, then a
strong cold front will cross the region from west to east Thursday
night. High pressure is expected to return Friday into Saturday
before another area of low pressure moves up and off the coast
Sunday. High pressure likely makes a return to start next week.

&&

.NEAR TERM /THROUGH THURSDAY NIGHT/...
Current surface analysis shows an area of low pressure centered
over IL. This area of low pressure will rapidly deepen as it
lifts northward into the Great Lakes overnight. As it lifts to
the north, it will move a surface warm front northward through
the area overnight. This will keep temperatures mild overnight,
with temperatures falling off briefly this evening, before
rising through the 50s to near 60 by daybreak. Winds will
increase out of the south and become quite gusty. Skies will
remain cloudy, with lower clouds moving in throughout the night.
However, most locations should remain dry through much of the
overnight.

Low pressure will continue to lift northward through southern
Quebec into western Ontario tomorrow. Showers will start to
break out across the area tomorrow morning as forcing for ascent
downstream of the approaching upper trough starts to overspread
the area. These showers will be focused primarily across
western portions of the forecast area during the morning hours
before gradually spreading eastward during the afternoon hours.
Skies should stay mostly cloudy, but a few filtered breaks of
sunshine may occur between the showers. By afternoon, most
locations should make it into the 70s (primarily due to
advection), with dewpoints climbing into the upper 50s to around
60. This will lead to the development of limited surface based
instability (on the order of 200-500 J/kg). Gentle height falls
downstream of the trough, coupled with the instability present
will lead to the development of thunderstorms across the area,
primarily during the afternoon and evening hours. Some CAMs
(notably the 00z HRRR and 00z FV3) have hinted at a relatively
cellular convective mode, which seems plausible given the
relatively gentle height falls and lack of a stronger shortwave
to encourage rapid upscale growth. Given the very strong shear
in place (70-90 knots of flow at mid-levels), any isolated cells
would become supercellular in nature. All hazards (tornadoes,
hail, and damaging winds) appear possible, especially if the
storm mode is primarily supercellular. Damaging winds appear to
be the primary threat, given the very strong low- level jet
that will be in place (50-70 knots at 1 km). Winds will be very
gusty, even outside of storms, with southerly winds in clear air
potentially approaching Wind Advisory criteria.

There may also be a threat for localized flash flooding. If the
convective mode does turn out more linear, there is a large
component of the flow aloft parallel to any initiating
boundaries, so there could be some localized training of storms
(in spite of the very fast storm motions). Any storms should
progress eastward throughout the evening hours. We`ll continue
to monitor the threat for severe storms through the night and
into the day tomorrow.
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57 minutes ago, yoda said:

5/5/15 is my guess on what the new Day 1 OTLK from SPC will show for our region tomorrow 

      Very reasonable.     I'm still debating the 2 vs 5 for the TOR, but there is a modest consensus for a few decent UH tracks, so a 5 area from DC to east-central PA is quite possible.

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2/5/15 on the new Day 1... but disco says higher probs possible depending on instability 

 

   ...North Carolina into the Lower Hudson Valley...
   A mid-level impulse will eject into the Hudson Valley during the
   afternoon and overspread the core of the low-level jet, promoting an
   intense tropospheric vertical wind profile and associated strong
   deep-layer shear. Enlarged hodographs from the Carolina Piedmont
   northward suggest storm organization with any convection that can
   intensify and become surface-based. The primary factor limiting the
   introduction of higher probabilities this outlook is scant buoyancy.
   5.5-6.5 C/km low- and mid-level lapse rates atop 55-60F surface
   dewpoints may promote SBCAPE up to 750 J/kg across North Carolina,
   to 250-500 J/kg into the Hudson Valley. Damaging gusts and a brief
   tornado may accompany any sustained, robust updrafts, hence the
   maintenance of a Category 2/Slight risk. Given 50-60 kt flow at/just
   below 500 meters AGL and the enlarged hodographs, higher
   wind/tornado probabilities may be needed in subsequent outlooks if
   it becomes evident that greater surface-based instability will be
   realized.
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Morning LWX AFD disco on the threat today... hope we can get some more instability then what is being modeled

 

Area Forecast Discussion
National Weather Service Baltimore MD/Washington DC
406 AM EDT Thu Mar 31 2022

.SYNOPSIS...

A strong cold front will approach the area later today, then cross
the area tonight. High pressure will build in Friday into Saturday.
A cold front and wave of low pressure are expected to move over the
area Saturday night into Sunday. High pressure is expected to make
another brief return early next week before unsettled weather
returns by the middle of next week.

&&

.NEAR TERM /THROUGH TONIGHT/...

Deepening surface cyclone over the western Great Lks will move
into western Quebec by tonight. Ahead of its associated cold
front, a strong low-lvl flow will develop over the area with
925 and 850 mb winds increasing to 45kt and 65kt respectively
by 18Z today. 500 mb heights will fall around 100 meters in 12
hours today leading to large scale ascent for upward vertical
motion. Widespread showers and low-topped thunderstorms are
expected beginning by 12Z across the Appalachian region and will
spread east through the day, exiting the Chesapeake Bay by 03Z
tonight. While instability will be limited (CAPE values
generally 250-500 J/kg), magnitude of low-lvl winds is such that
any showers or thunderstorms will be capable of producing
damaging wind gusts. Even outside of showers, gradient winds are
strong enough to support 40-45 mph winds. While deep layer shear
is strong enough to support supercells, limited instability will
likely limit tornado potential. Most CAMs indicate a linear mode
of convection with a squall line moving through the area in the
18Z-02Z time frame. There will also be a low risk for flooding
across northeast Maryland where models indicate some training
convection possible. Showers will exit by 06Z but upslope
rain/snow showers will persist into Friday.
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Hazardous Weather Outlook
National Weather Service Baltimore MD/Washington DC
530 AM EDT Thu Mar 31 2022

ANZ530>543-DCZ001-MDZ008-011-013-014-016>018-504-506-508-
VAZ052>057-010930-
Chesapeake Bay north of Pooles Island MD-
Chesapeake Bay from Pooles Island to Sandy Point MD-
Chesapeake Bay from Sandy Point to North Beach MD-
Chesapeake Bay from North Beach to Drum Point MD-
Chesapeake Bay from Drum Point MD to Smith Point VA-
Tidal Potomac from Key Bridge to Indian Head MD-
Tidal Potomac from Indian Head to Cobb Island MD-
Tidal Potomac from Cobb Island MD to Smith Point VA-
Patapsco River including Baltimore Harbor-
Chester River to Queenstown MD-Eastern Bay-
Choptank River to Cambridge MD and the Little Choptank River-
Patuxent River to Broomes Island MD-
Tangier Sound and the inland waters surrounding Bloodsworth
Island-District of Columbia-Cecil-Southern Baltimore-
Prince Georges-Anne Arundel-Charles-St. Marys-Calvert-
Central and Southeast Montgomery-Central and Southeast Howard-
Southeast Harford-Prince William/Manassas/Manassas Park-Fairfax-
Arlington/Falls Church/Alexandria-Stafford-Spotsylvania-
King George-
530 AM EDT Thu Mar 31 2022

This Hazardous Weather Outlook is for the Maryland portion of the
Chesapeake Bay, Tidal Potomac River, and I-95 corridor through
central Maryland, northern Virginia, and District of Columbia.

.DAY ONE...Today and Tonight

Scattered severe thunderstorms are possible this afternoon and
evening. Damaging wind gusts are the main threat, but hail or a
few tornadoes are possible as well. Strong winds may lead to
isolated instances of wind damage even outside of thunderstorms.
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10 minutes ago, WinterWxLuvr said:

You guys keep hoping for this stuff, one day you’re gonna get it.

Severe is cool to track I guess, but other than heavy rain and T&L, I don't want it imy. Had a severe storm a couple summers ago that blew a tree down, but luckily it was well out in front of the house and only partially blocked the driveway. It was good firewood the last 2 winters.

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34 minutes ago, WinterWxLuvr said:

You guys keep hoping for this stuff, one day you’re gonna get it.

Yes, we can all hope one day our houses get destroyed by a tornado or very strong winds. I've never understood the desire to have it actually happen at your house when it comes to really bad severe weather.

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19 minutes ago, osfan24 said:

Yes, we can all hope one day our houses get destroyed by a tornado or very strong winds. I've never understood the desire to have it actually happen at your house when it comes to really bad severe weather.

Nobody is asking for a wedge to level their house. It's the tracking of interesting weather. We don't control whether it happens or not. Might as well track it. 

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        It's worth noting that the HRRR has trended this morning towards the NAM Nest idea of a later show for those of us in central MD     This isn't ideal, as while temps won't be plummeting after sunset, we need every degree of heating we can get, given that we're looking at very limited instability even at peak heating.    Areas further west and north look to have a better shot at SVR due to more favorable timing, unless some scattered cells form out ahead of the primary line or if the line advances further to the southeast earlier.

      

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Interesting re bolded 

.Southeastern CONUS to Hudson Valley region...
   The earliest threat area is ongoing -- across portions of the FL
   Panhandle, southern GA and northwestern FL.  See SPC tornado watch
   85 and related mesoscale discussions for details on the near-term
   threats with this activity.

   A broad plume of low-level theta-e advection will combine with muted
   diurnal heating to at least marginally destabilize the boundary
   layer today, in a broad swath from the Carolinas into the northern
   Mid-Atlantic.  This will support additional bands of scattered to
   numerous showers, and widely scattered to scattered thunderstorms,
   expected to develop from the southern Piedmont to the central
   Appalachians and move quickly northeastward across the outlook area
   today.  A mixed mode of QLCS (bows, LEWPs and embedded mesovortices)
   and a few supercells are possible, supporting a threat for damaging
   gusts (a few severe at 50+ kt intensity) and a few tornadoes.

   With weakly unstable lapse rates, preconvective dewpoints reaching
   the mid 50s north to mid 50s south will be counterbalanced by
   somewhat colder air aloft in the mid-Atlantic, warmer over the
   Carolinas to Delmarva.  The 12Z IAD sounding sampled a likely narrow
   ribbon of a remnant of the southern Plains EML, within a broader
   area of weak 600-800-mb lapse rates.  Peak warm-sector MLCAPE should
   reach the 100-500 J/kg range over the Mid-Atlantic and 500-1000 J/kg
   over the Carolinas, and 1000-1500 J/kg in southeastern GA and
   northern FL.

   As noted above, the strongest mid/upper winds will be over the
   middle parts of the outlook area today, while a 60-75-kt LLJ takes
   shape from the Carolinas into the eastern Mid-Atlantic.  This will
   foster effective-shear magnitudes peaking around 60-75 kt in the
   NC/VA/MD region, decreasing but still strong northward and
   southward.  Meanwhile, lengthy hodographs will support effective SRH
   in the 200-400 J/kg range over much of the corridor.  Strongest
   forcing for ascent should be ahead of the front in the northern
   parts of the area where buoyancy is weakest, in a strong-shear/
   low-CAPE scenario.  Uncertainty remains as to coverage of severe
   gusts reaching the surface given some constraints on low-level lapse
   rates, but even subsevere winds will be capable of minor structural
   damage and trees down.

   ..Edwards/Broyles.. 03/31/2022
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9 minutes ago, yoda said:

Interesting re bolded 

.Southeastern CONUS to Hudson Valley region...
   The earliest threat area is ongoing -- across portions of the FL
   Panhandle, southern GA and northwestern FL.  See SPC tornado watch
   85 and related mesoscale discussions for details on the near-term
   threats with this activity.

   A broad plume of low-level theta-e advection will combine with muted
   diurnal heating to at least marginally destabilize the boundary
   layer today, in a broad swath from the Carolinas into the northern
   Mid-Atlantic.  This will support additional bands of scattered to
   numerous showers, and widely scattered to scattered thunderstorms,
   expected to develop from the southern Piedmont to the central
   Appalachians and move quickly northeastward across the outlook area
   today.  A mixed mode of QLCS (bows, LEWPs and embedded mesovortices)
   and a few supercells are possible, supporting a threat for damaging
   gusts (a few severe at 50+ kt intensity) and a few tornadoes.

   With weakly unstable lapse rates, preconvective dewpoints reaching
   the mid 50s north to mid 50s south will be counterbalanced by
   somewhat colder air aloft in the mid-Atlantic, warmer over the
   Carolinas to Delmarva.  The 12Z IAD sounding sampled a likely narrow
   ribbon of a remnant of the southern Plains EML, within a broader
   area of weak 600-800-mb lapse rates.  Peak warm-sector MLCAPE should
   reach the 100-500 J/kg range over the Mid-Atlantic and 500-1000 J/kg
   over the Carolinas, and 1000-1500 J/kg in southeastern GA and
   northern FL.

   ..Edwards/Broyles.. 03/31/2022

SPC meso analysis picked up some okay mid level lapse rates from Baltimore NE into Reading. That might be what they're talking about?

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1 minute ago, yoda said:

LCLs were basically in the 500s... so yes lol

okey dokey. You all are basically fired up about wanting/begging for sun usually for severe, but maybe we don't need that this time. Because we sure as shit don't have it in northern areas. 

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19 minutes ago, North Balti Zen said:

okey dokey. You all are basically fired up about wanting/begging for sun usually for severe, but maybe we don't need that this time. Because we sure as shit don't have it in northern areas. 

can confirm. was cloudy when i left parkton, cloudy in hunt valley

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