2024 Severe Weather General Discussion

[high risk]

12 minutes ago, Kmlwx said:

NW flow comes to mind. That could be what they are referencing. If a little kink in the flow can come at us at the right angle, perhaps even with some EML advecting from the west, we could do very well. GFS has teased us with a few potential threats in the fantasy ranges the last few runs. 

       Right, but northern stream events here early in the season often struggle with instability, as it's tough to get good low-level moisture north at this time of year without some help.

[Kmlwx]

36 minutes ago, high risk said:

       Right, but northern stream events here early in the season often struggle with instability, as it's tough to get good low-level moisture north at this time of year without some help.

I'm a little more optimistic the later into May we get. Obviously, it would be helpful is we had June heat/humidity available. 

[nw baltimore wx]

3 hours ago, AdamHLG said:

 I would say that was no Accident - but based on the Facebook post it appears it was.

[Eskimo Joe]

NWS Sterling confirms 2 tornadoes from Saturday: https://www.weather.gov/lwx/GarrettTorsMay2024

[Eskimo Joe]

3 hours ago, yoda said:

Do northern stream s/w's bring about our better severe weather threats?  There was an interesting tidbit at the end of this mornings AFD 

Upper level ridging tries to build back into the area Sunday into
Monday bringing slightly drier conditions. Another front will follow
with renewed chances for showers and thunderstorms Tuesday and
Wednesday next week. Temperatures will continue to warm back above
average during this time leading to the potential for greater
instability for thunderstorm activity to feed off of. With a fairly
active northern stream will continue to monitor for any severe
weather or hydro threats within the extended period. Right now,
there is no mention in the Day 4-8 outlook from the Storm Prediction
Center.

Northwest flow regimes can advent EMLs, which work to offset the many terrain issues that mitigate severe weather in this part of the country.

[Kmlwx]

GFS is very lame (in terms of parameters) though nearly the end of the run. Will see how this changes the in the coming days.

[yoda]

14 hours ago, Eskimo Joe said:

NWS Sterling confirms 2 tornadoes from Saturday: https://www.weather.gov/lwx/GarrettTorsMay2024

2 EF1s... pretty decent for around here

[yoda]

LWX mentions Wednesday as next chance for some severe storms in the afternoon AFD 

Fairly potent system approaches the area by Wednesday, with a cold
front advanced out ahead of the system. Guidance has been hinting at
the opportunity for increased instability ahead of the frontal
passage. Could see some thunderstorms develop, with some getting
strong to severe. Still a lot of uncertainty with this system with
respect to timing and intensity. Highs on Wednesday will be in the
upper 70s to low 80s.

[Kmlwx]

Paging @Eskimo Joe - the 18z GFS throws at least some semblance of better-than-normal mid-level lapse rates our way a few times next week. 

[Eskimo Joe]

39 minutes ago, Kmlwx said:

Paging @Eskimo Joe - the 18z GFS throws at least some semblance of better-than-normal mid-level lapse rates our way a few times next week. 

Count on it. I'm in Alaska until Memorial Day.

[yoda]

Meanwhile in Houston

33 minutes ago, WxWatcher007 said:

Grid demolished. Over a million outages statewide and 40% of Harris County without power. 

 

 

[Eskimo Joe]

13 hours ago, yoda said:

Meanwhile in Houston

Legit derecho 

[yoda]

LWX hinting at chance of severe next week in their afternoon AFD 

LONG TERM /TUESDAY THROUGH SATURDAY/...
A broad upper level ridge is forecast to be remain in place over the
eastern seaboard on Tuesday with high pressure at the surface. A
southerly return flow will lead to increasingly warming
temperatures through the middle parts of next week. The SFC high
pressure on Tuesday will keep the region dry, but an approaching
cold front from the west will bring increasing chances for showers
and thunderstorms Wednesday through Friday. Model guidance has
trended slower with the mid-week system and there remains some
uncertainty if there will be enough instability (CAPE) that overlaps
with the favorable period for shear to produce a threat for severe
weather. SPC is focusing on the Ohio Valley for SVR weather
Wednesday into Thursday, but the CIPS machine learning model
continues to suggest that there is a chance for isolated severe
weather in our region during the middle and later parts of next
week.

 

[yoda]

Thursday sounds interesting... from this mornings AFD 

.LONG TERM /THURSDAY THROUGH SUNDAY/...
To the south of a deep upper trough tracking across Quebec will
be a series of lower amplitude waves that race toward the Mid-
Atlantic region on Thursday. As this occurs, a slow moving cold
front is expected to push through the local area by midday into
the evening hours. There is fairly strong mid/upper support with
a belt of 500-mb west-southwesterlies around 40 to 50 knots.
This is accompanied by ample right entrance region jet dynamics
within a jet streak running between 100 to 110 knots. The key
parameter that will dictate the degree of severe weather threat
is the instability. At this point, even global ensembles are
showing around 1,000 to 1,500 J/kg of surface-based CAPE on
Thursday. This would be more than adequate to support severe
convection given the extent of vertical shear in the profile.
However, as usual, the near to short term trends of cloud cover
which inhibits convective potential will need to be monitored
ahead of the event. Besides the threat for showers and
strong/severe thunderstorms, it should be a very warm day with
decent humidity owing to persistent south-southwesterlies.
Forecast highs are in the mid/upper 80s, with heat indices
approaching the low 90s. The frontal boundary eventually slides
off to the south by Friday morning.

[yoda]

LWX mentions very isolated threat tomorrow, chance on Thursday, and then possibly substantial on Monday in the morning AFD 

Deep layer shear is expected to remain weak Wednesday (AOB 20
kts sfc-500 hPa). However, flow will increase subtly later in
the day, and heights will begin to come down slightly as well.
This, coupled with above normal temperatures and increasing
humidity and instability will lend to a threat of at least
widely scattered showers and thunderstorms come afternoon. The
threat appears greatest west of I-95 further away from the
departing ridge and any associated subsidence. A couple storms
could produce a little hail or gusty winds given the increased
instability, but the lack of shear will probably keep a more
organized or widespread severe weather threat marginal, and
relegated to north of US-33/west of US-15 for the most part.

Heights fall more appreciably on Thursday as a surface cold
front impinges on the area. Latest guidance times the front
favorably with peak heating. The background airmass will be very
warm and humid, but cloud debris from previous day`s convection
over the middle of the country could inhibit more significant
CAPE. If higher instability is realized, a more organized threat
for strong to severe thunderstorm clusters could develop given
the strong surface front and increasing flow/shear aloft in the
right entrance region of a seasonably strong upper jet. The
threat for strong to severe thunderstorms may be greater south
of US-50/I-66 and east of US-15 where the potential for more
heating is highest.

Activity should gradually dissipate heading into Thursday night
as daytime instability wanes and the front sags south. But, the
front`s progress will be slow, so the potential of showers may
linger well into the night south of US-50/I-66.

&&

.LONG TERM /FRIDAY THROUGH MONDAY/...

A front will remain generally north of the Pennsylvania Turnpike
through early next week keeping the local area in a warm and humid
air mass with the risk of almost daily afternoon and early evening
showers and thunderstorms. A well defined 700 mb shortwave-trough is
fcst to approach the area Fri night with its axis crossing the area
around 18Z Saturday. With shear vectors on the weaker side and slow
storm motions, storms Fri afternoon and evening may pose a risk of
heavy rainfall and flash flooding. Saturday`s threat really depends
on the timing of that shortwave as it appears the trough axis will
be too far east to enhance t-storm activity.

On Sunday, the models show significant 925-850 mb drying under low-
mid level ridging, which is likely to keep t-storm activity isolated
at best.

On Monday, a potent shortwave-trough and attendant sfc cyclone will
move across Ohio and northern Mid-Atlantic. This system could pose a
more substantial severe wx threat given strong winds aloft
especially if the timing of the frontal passage coincides with
peak heating. The latest timing suggests a severe threat
during the morning hours, but things could definitely still
change between now and next Monday.

[Kmlwx]

At this point I'm pretty meh on the remainder of the week. We'll see about Thursday. Intrigued (for now) on Monday. Doldrums around here lately.

[09-10 analogy]

30 minutes ago, yoda said:

LWX mentions very isolated threat tomorrow, chance on Thursday, and then possibly substantial on Monday in the morning AFD 

Deep layer shear is expected to remain weak Wednesday (AOB 20
kts sfc-500 hPa). However, flow will increase subtly later in
the day, and heights will begin to come down slightly as well.
This, coupled with above normal temperatures and increasing
humidity and instability will lend to a threat of at least
widely scattered showers and thunderstorms come afternoon. The
threat appears greatest west of I-95 further away from the
departing ridge and any associated subsidence. A couple storms
could produce a little hail or gusty winds given the increased
instability, but the lack of shear will probably keep a more
organized or widespread severe weather threat marginal, and
relegated to north of US-33/west of US-15 for the most part.

Heights fall more appreciably on Thursday as a surface cold
front impinges on the area. Latest guidance times the front
favorably with peak heating. The background airmass will be very
warm and humid, but cloud debris from previous day`s convection
over the middle of the country could inhibit more significant
CAPE. If higher instability is realized, a more organized threat
for strong to severe thunderstorm clusters could develop given
the strong surface front and increasing flow/shear aloft in the
right entrance region of a seasonably strong upper jet. The
threat for strong to severe thunderstorms may be greater south
of US-50/I-66 and east of US-15 where the potential for more
heating is highest.

Activity should gradually dissipate heading into Thursday night
as daytime instability wanes and the front sags south. But, the
front`s progress will be slow, so the potential of showers may
linger well into the night south of US-50/I-66.

&&

.LONG TERM /FRIDAY THROUGH MONDAY/...

A front will remain generally north of the Pennsylvania Turnpike
through early next week keeping the local area in a warm and humid
air mass with the risk of almost daily afternoon and early evening
showers and thunderstorms. A well defined 700 mb shortwave-trough is
fcst to approach the area Fri night with its axis crossing the area
around 18Z Saturday. With shear vectors on the weaker side and slow
storm motions, storms Fri afternoon and evening may pose a risk of
heavy rainfall and flash flooding. Saturday`s threat really depends
on the timing of that shortwave as it appears the trough axis will
be too far east to enhance t-storm activity.

On Sunday, the models show significant 925-850 mb drying under low-
mid level ridging, which is likely to keep t-storm activity isolated
at best.

On Monday, a potent shortwave-trough and attendant sfc cyclone will
move across Ohio and northern Mid-Atlantic. This system could pose a
more substantial severe wx threat given strong winds aloft
especially if the timing of the frontal passage coincides with
peak heating. The latest timing suggests a severe threat
during the morning hours, but things could definitely still
change between now and next Monday.

Yeah, it seems pretty rare for an AFD to start honking about a severe threat almost a week away. Hope things evolve so that the threat is a little later in the day on Monday; that is, if it comes to fruition at all. 

[Kmlwx]

18 minutes ago, 09-10 analogy said:

Yeah, it seems pretty rare for an AFD to start honking about a severe threat almost a week away. Hope things evolve so that the threat is a little later in the day on Monday; that is, if it comes to fruition at all. 

The one thing is that they probably mean substantial relative to this week's threats (which seem marginal for now). So "more substantial" could mean just a step above that. 

[yoda]

National Weather Service Baltimore MD/Washington DC
409 AM EDT Wed May 22 2024

ANZ530>543-DCZ001-MDZ008-011-013-014-016>018-504-506-508-
VAZ053>057-527-230815-
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-Fairfax-Arlington/Falls Church/Alexandria-
Stafford-Spotsylvania-King George-
Central and Southeast Prince William/Manassas/Manassas Park-
409 AM EDT Wed May 22 2024

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

Widely scattered thunderstorms are forecast this afternoon and
evening. A couple isolated severe thunderstorms with damaging wind
gusts and hail are possible, mainly between 6 PM and 10 PM.

Thunderstorms may also produce hazardous winds and waves over area
waterways late this afternoon and evening.

.DAYS TWO THROUGH SEVEN...Thursday through Tuesday

Scattered to numerous thunderstorms are likely Thursday afternoon
and early evening. A few storms may be severe with damaging wind
gusts and large hail.

Daily thunderstorm chances are forecast through the upcoming
holiday weekend. A few storms may be severe during the afternoon
and evening hours, particularly Saturday and Monday.

.SPOTTER INFORMATION STATEMENT...

Spotter activation may be needed at times.

 

[yoda]

SPC day 4 to 8 OTLK has a mention

 

   ...Days 6-8/Mon-Wed...

   Spread among model guidance increases quite a bit by Monday. Some
   severe potential is possible anywhere from the Southern states to
   the Mid-Atlantic as the upper trough lifts east/northeast. However,
   details regarding storm evolution on Day 5/Sun into early Monday,
   along with differing evolution of the surface pattern by various
   guidance results in low predictability. 

   By Tuesday and Wednesday, an upper ridge is expected to move from
   the western U.S. into the Plains. This should mostly shut down
   severe potential west of the MS River.

[yoda]

Morning disco talking up tomorrow potential and Memorial Day

.SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
Stronger forcing for ascent will move into the area Thursday
attendant to an upper trough and strong surface cold front
approaching from the Midwest. Cloud debris and the front
approaching during the early part of the peak heating window
casts some uncertainty to the extent of instability. But, with
stronger forcing and shear, there is at least a conditional risk
for more organized strong to severe thunderstorms. It remains to
be seen just how widespread the threat is, but storms may tend
to focus further south and east toward the I-95 corridor where
the potential for heating will last longest.

Trends will need to be closely monitored over the next 24 hours,
as upstream convection over the Midwest will dictate subtle
shifts in (1) vort maxes embedded in the large scale flow, and
(2) the extent of cloud debris that could inhibit heating.

The front itself likely stalls to the north, but a wind shift or
pre-frontal trough type feature should shift south Thursday
night. Given the front(s) nearby, and lingering troughing and
moisture, shower activity could last well into the night.

Additional waves along the stalled front may lead to an
unsettled Friday, as well. Although forcing and instability look
to be a bit less, shower and thunderstorm potential will still
be there especially further south near the I-64 corridor closer
to the wind shift. It does not look like it will rain the entire
day, but rather the potential for showers and thunderstorms will
linger, with chances cresting during peak diurnal heating.

&&

.LONG TERM /SATURDAY THROUGH TUESDAY/...

The weather pattern over the Memorial Day holiday weekend will
be characterized by gradually lowering heights and surface
pressures leading to a stormy pattern. Saturday should turn out
rather active due to a low amplitude shortwave trough moving
across the area that should act to enhance t-storm activity.
Sunday appears to be the least active day due to shortwave
ridging and some drying. Severe weather risk appears to increase
markedly on Memorial Day due to strengthening wind fields aloft
and strong shortwave energy moving across the area around the
base of a deep upper level trough over the eastern Great Lks. A
strong cold front will follow Monday night bringing cooler and
drier conditions for the middle of next week.

[yoda]

12z NAM NEST and 12z NAM look decent around 6 to 8pm

13z HRRR is nice as well, stormy for the region after 22z to the end of its run 

[George BM]

24 minutes ago, yoda said:

12z NAM NEST and 12z NAM look decent around 6 to 8pm

13z HRRR is nice as well, stormy for the region after 22z to the end of its run 

Yeah CAPE actually looks fairly decent later, especially towards the mountains (1500-2000+ mlcape). With modest shear in place as well a few warned storms wouldn't surprise me later... especially out that way.

[yoda]

SPC has nudged the eastern extent of the MRGL risk to the i95 corridor on the 1630z OTLK

[yoda]

MCD out for our far NW zones 

https://www.spc.noaa.gov/products/md/md0891.html

 

 

Mesoscale Discussion 0891
   NWS Storm Prediction Center Norman OK
   1128 AM CDT Wed May 22 2024

   Areas affected...Western New York into parts upper Ohio Valley

   Concerning...Severe potential...Watch possible 

   Valid 221628Z - 221830Z

   Probability of Watch Issuance...40 percent

   SUMMARY...A severe thunderstorm watch is possible for parts of
   western/central New York into the upper Ohio Valley. Damaging winds
   will be the primary threat. An isolated brief tornado and large hail
   may occur with the stronger, more organized activity.

   DISCUSSION...Convection has been most intense right ahead of an MCV
   tracking into northwest Pennsylvania and southwestern New York.
   Destabilization continues to occur ahead of this activity and
   farther south into western Pennsylvania and vicinity. Convection is
   likely to continue in close proximity to the MCV as well as
   additional development within the Allegheny Mountains. Buoyancy may
   be more limited into southeast Ohio/northern West Virginia due to
   cloud cover. Observed morning soundings from the region showed
   mid-level lapse rates around 7 C/km. Deep layer shear this far east
   will be weaker given the displacement from the primary synoptic wave
   in the Upper Midwest. However, some modest increase in shear should
   occur through the day. Storms will be capable of damaging winds
   primarily. Some risk for a brief tornado is also evident given
   modest low-level hodograph turning on area VAD profiles. Large hail
   could occur with the strongest storms, but weak upper-level flow
   will likely keep this threat more isolated. A watch may eventually
   be needed should convective trends warrant.

   ..Wendt/Hart.. 05/22/2024

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

   ATTN...WFO...BGM...BUF...CTP...LWX...PBZ...RLX...CLE...

[09-10 analogy]

1 hour ago, yoda said:

MCD out for our far NW zones 

https://www.spc.noaa.gov/products/md/md0891.html

 

 

Mesoscale Discussion 0891
   NWS Storm Prediction Center Norman OK
   1128 AM CDT Wed May 22 2024

   Areas affected...Western New York into parts upper Ohio Valley

   Concerning...Severe potential...Watch possible 

   Valid 221628Z - 221830Z

   Probability of Watch Issuance...40 percent

   SUMMARY...A severe thunderstorm watch is possible for parts of
   western/central New York into the upper Ohio Valley. Damaging winds
   will be the primary threat. An isolated brief tornado and large hail
   may occur with the stronger, more organized activity.

   DISCUSSION...Convection has been most intense right ahead of an MCV
   tracking into northwest Pennsylvania and southwestern New York.
   Destabilization continues to occur ahead of this activity and
   farther south into western Pennsylvania and vicinity. Convection is
   likely to continue in close proximity to the MCV as well as
   additional development within the Allegheny Mountains. Buoyancy may
   be more limited into southeast Ohio/northern West Virginia due to
   cloud cover. Observed morning soundings from the region showed
   mid-level lapse rates around 7 C/km. Deep layer shear this far east
   will be weaker given the displacement from the primary synoptic wave
   in the Upper Midwest. However, some modest increase in shear should
   occur through the day. Storms will be capable of damaging winds
   primarily. Some risk for a brief tornado is also evident given
   modest low-level hodograph turning on area VAD profiles. Large hail
   could occur with the strongest storms, but weak upper-level flow
   will likely keep this threat more isolated. A watch may eventually
   be needed should convective trends warrant.

   ..Wendt/Hart.. 05/22/2024

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

   ATTN...WFO...BGM...BUF...CTP...LWX...PBZ...RLX...CLE...

Another Garrett County special ..?

[midatlanticweather]

Watch is up

[high risk]

That watch box comes further east than I expected

[KAOS]

[vastateofmind]

15 minutes ago, midatlanticweather said:

Watch is up

So...did anyone with a wx radio get the actual alarm/notification on this? I see it was issued at 3:09, but my alarm didn't go off at all in the last 10 min.