2025 Severe Weather General Discussion

[Kmlwx]

Still out in the long range...but the GFS would seem to suggest the doldrums may be coming to an end. CIPS is also starting to latch onto increased severe potential out beyond 200 hours. The 06z GFS run had decent parameters on SEVERAL days out in the long range.

[yoda]

On 5/8/2025 at 8:24 AM, Kmlwx said:

Still out in the long range...but the GFS would seem to suggest the doldrums may be coming to an end. CIPS is also starting to latch onto increased severe potential out beyond 200 hours. The 06z GFS run had decent parameters on SEVERAL days out in the long range.

Day 4-8 Convective Outlook  
   NWS Storm Prediction Center Norman OK
   0400 AM CDT Sat May 10 2025

   Valid 131200Z - 181200Z

   ...DISCUSSION...
   Medium-range guidance indicates that a generally amplified, split
   mid/upper flow will persist across the mid-latitude Pacific through
   North America next week.  It appears that this will include at least
   a couple of significant troughs digging inland of the U.S. Pacific
   Coast.  The first may already be in the process of developing
   eastward across the Intermountain West early in this period
   (Tuesday), before progressing across the Rockies, Great Plains and
   Mississippi Valley during the middle through latter portion of next
   week.  This may be followed by another significant trough digging
   inland of the Pacific coast by early next weekend.

   The lead trough will be relatively close on the heels of the
   remnants of an initially broad quasi-stationary/cut-off low, which
   may only slowly progress east of the Mississippi Valley through
   Atlantic Seaboard during the early to middle portion of next week. 
   Low-level moisture return, in the wake of this perturbation and
   ahead of the mid-level trough emerging from the West, may continue
   to be impacted across at least parts of the Great Plains into mid
   week.  Thereafter, there appears a general consensus that there will
   be a better coupling of large-scale forcing for ascent, aided by
   surface cyclogenesis, with a notable increase in low-level moisture
   and destabilization across the lower Missouri Valley into the Upper
   Midwest and lower Ohio Valley by late next Thursday into Thursday
   night.  In the presence of strong shear, it appears that this
   environment could become supportive of supercells and/or one or two
   organizing severe storm clusters.

   Machine learning output and other guidance suggests that potential
   for strong to severe thunderstorms could persist and potentially
   become more widespread across the Ohio Valley into Mid Atlantic, and
   southern Great Plains, next Friday and Saturday.  However,
   uncertainties remain too large at this time to introduce greater
   than 15 percent severe probabilities.

   ..Kerr.. 05/10/2025

[yoda]

Next Friday into the weekend looks intriguing per afternoon AFD from LWX 

After a short reprieve, the system later in the week will have a lot
more fuel to work with. As high temperatures on Friday are expected
to rise into the mid/upper 80s (coupled with dew points approaching
70 degrees), instability should be plentiful. Some strong to severe
thunderstorms are possible as this system tracks through on Friday
into early next weekend. Details hopefully become more apparent in
the next few days.

 

[yoda]

@Kmlwx @Eskimo Joe  @high risk

this sounds great for now lol (from the afternoon AFD from LWX)

As we move toward the end of the week, a deep upper low and
attendant strong surface low will slowly track eastward into the
Upper Great Lakes. As this occurs, rich low-level moisture will be
drawn north and east from the Gulf into the Ohio Valley and Mid-
Atlantic. Simultaneously, a strong belt of mid-level flow (35-50
knots in the 700-500 hPa layer) will spread overtop that rich low-
level moisture, advecting a remnant elevated mixed layer plume
eastward as it does so. Rich low-level moisture, steeper than
climatology mid-level lapse rates, and strong mid-level flow will
result in an environment on Friday, and potentially even Saturday as
well, characterized by both strong instability and strong deep layer
shear. The EPS and GEPS ensemble means have 2000-3000 J/kg CAPE
along with 35-50 knots of 0-6 km bulk shear. The GEFS show lesser
instability and similar shear values, but have a well-know low bias
when it comes to instability. This type of parameter space raises
concerns for severe thunderstorms. While the parameter space being
advertised at the moment by models is toward the higher end of what
we typically see in this part of the country, we`re still at day 6
and 7, and there is plenty of time for things to change, especially
when an upper level low is involved (which models notoriously
struggle with in the long range). With an elevated mixed layer
involved, there are also signs of stronger capping than we typically
see, so that could complicate things as well. For now, the end of
the week is a period to monitor for potential severe thunderstorms,
with the expectation that the forecast can and will change this far out.

[Kmlwx]

If nothing else - instability looks better than prior events so far this year. Still so far out - we'll see. (my famous two words)

[andyhb]

The 12z UK is a must check for shits and giggles for this region.

[Kmlwx]

Would fit well with our little local "tornado alley" down near EZF and across the bay into the La Plata/Southern Maryland area. Seems some of the guidance (not that it matters much at this range) wants to push the main threat to our south. That AI convective NCAR page is honking a bit for the Fri-->Sat timeframe though. 

[high risk]

6 hours ago, Kmlwx said:

Would fit well with our little local "tornado alley" down near EZF and across the bay into the La Plata/Southern Maryland area. Seems some of the guidance (not that it matters much at this range) wants to push the main threat to our south. That AI convective NCAR page is honking a bit for the Fri-->Sat timeframe though. 

 Fri/Sat is definitely worth watching, but there is a lot of disagreement on whether we get decent height falls or if they're focused more north of here.    Any modest height falls would probably bring a severe threat, given the good moisture in place and good wind fields.

[yoda]

Morning AFD from LWX on the threat 

By Fri, another ULL will track eastward toward the Great Lakes. At
the surface, a notable moisture return will occur from the Gulf of
America into the Ohio Valley and Mid-Atlantic Fri into Sat. This
will be coupled with some of the warmest temperatures of the spring
thus far (mid to upper 80s both days), resulting in modest
instability. The combination of low-level moisture, steep low-level
lapse rates, steep for the Mid-Atlantic mid-level lapse rates, and
strong flow will yield the potential for strong to severe
thunderstorms. Depending on timing of cold front, Saturday may be
the more active day, or it may be to the south of the area. Will
continue to monitor. Regardless, the end of the week could yield a
couple days of severe weather. High pressure may briefly move in
Sun, but uncertainties with frontal positioning and the next
shortwave over the Ohio Valley exist.