Central PA Spring 2026 Discussion/Obs Thread

[canderson]

New day 3 is out

 

 

 Day 3 Convective Outlook  
   NWS Storm Prediction Center Norman OK
   0238 PM CDT Sat Mar 14 2026

   Valid 161200Z - 171200Z

   ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS FROM SC TO
   SOUTHERN PA...

   ...SUMMARY...
   Scattered to widespread severe storms are likely on Monday for parts
   of the Mid-Atlantic States and Southeast. The greatest potential for
   strong tornadoes and significant damaging winds appears centered on
   parts of South Carolina to Maryland during the late morning to
   afternoon.

   ...Mid-Atlantic and Southeast...
   Primary changes this outlook are to add a 45 total severe
   probability along with minor northeast and southeast expansion to
   the categorical risk areas. Portions of the region, centered on SC
   to MD, may warrant an upgrade to a level 4/Moderate Risk in later
   outlooks.

   A large and deepening upper trough will eject east/northeastward out
   of the MS/OH/TN Valleys and across the Appalachians and into the Mid
   Atlantic/Northeast on Monday, with an expansive area of strong to
   intense wind fields aloft. A deep cyclone will move from Lower MI
   into QC, with an occluding cold front arcing southeast across the
   northern Appalachians, then south-southwest into the northern Gulf.
   This front will clear all but the FL Peninsula by Monday evening.

   Ahead of the front, seasonably rich low-level moisture characterized
   by 60s surface dew points will spread northward from the eastern
   Gulf/western Atlantic. Convection will likely be ongoing at 12Z
   Monday, low-topped along the Upper OH Valley to central Appalachian
   portion of the front to deep convection in the lee of the southern
   Appalachians to eastern FL Panhandle. A diurnal uptick in storm
   intensity, including potential for semi-discrete supercells ahead of
   the front, should occur from north FL to the Carolina Piedmont.
   Further intensification is anticipated midday into the afternoon as
   a confined corridor of moderate buoyancy likely develops just ahead
   of morning storms.

   Enlarged low-level hodograph curvature, in conjunction with
   favorable elongation of the mid/upper hodograph, should foster a mix
   of broken supercells south with line-embedded supercells in the
   reinvigorated QLCS north. With such intense 700-mb flow aptly timed
   with the diurnal heating cycle overlying rich low-level moisture,
   setup could yield an expansive severe weather day, including strong
   tornadoes and significant damaging winds. The degree of
   boundary-layer heating, as well as timing of convection that may
   outpace the front late D2 into early D3, will play key roles in how
   intense severe magnitudes may become. At present, the most likely
   corridor for significant/widespread severe appears centered on the
   eastern Piedmont to coastal plain from SC to MD around midday into
   the afternoon.

[canderson]

@Voyager

https://x.com/brody_wx/status/2032851932704886856?s=61&t=u98k6PBLbHMnYtCcWaeK4g 

[Voyager]

19 minutes ago, canderson said:

@Voyager

https://x.com/brody_wx/status/2032851932704886856?s=61&t=u98k6PBLbHMnYtCcWaeK4g 

Unbelievable. And here we (I anyway) freeze. I really hate that we've been "locked in" to this pattern all winter. 

[Blizzard of 93]

18z NAM likes the idea of back end snow Monday evening.

[canderson]

That’ll be bad for the crews who will be out trying restore power, cutting up fallen trees, helping those with roof damage and all 

[Itstrainingtime]

5 minutes ago, canderson said:

That’ll be bad for the crews who will be out trying restore power, cutting up fallen trees, helping those with roof damage and all 

Yes, snow and cold are about the worst things that could happen IF there is widespread damage/power outages which certainly seems possible.

[Yardstickgozinya]

The latest nws take on severe and snow. Plenty to be worked out yet ,but I get the feeling, this is all going  to work out for the best or the worst, depending on how you look at it. Exciting times ahead. 

Monday continues to be a period of high focus, as model
consensus zeroes in on the potential for significant convective
development. At this early juncture, confidence is quite high
on the synoptic-scale evolution (the approach of a negatively
tilted upper-trough, an associated sharp cold front, and
impressively strong wind fields at all levels). More uncertainty
still has to be dealt with, though, in terms of smaller-scale
factors, such as: exact timing of the cold frontal passage, can
any breaks develop in the overcast conditions that should
prevail to start the day (which would enhance instability)?, and
convective mode (will any discrete cells form ahead of a
probable intense squall line?). Bottom line, though, ultimately
we have increasing levels of confidence in high wind producing
thunderstorms Monday afternoon, with the best potential for
damaging gusts near and south of I-80, as well as east of I-99.
Please stay tuned for later updates over the next couple of
days.

KEY MESSAGE 2: Following Monday storminess, a period of sharply
colder temperatures is expected through mid-week, with some
snow possible Monday night, as the cold air first builds in.

On Monday evening, once the surface cold front pushes through,
colder air should rush in. At issue is how much steadier
precipitation will linger behind the boundary. Given favorable
upper jet placement and the probability that some wrap-around
moisture will get steered into the Commonwealth, there is the
potential for a quick 1-3" of snow in some areas Monday night,
particularly over the higher terrain and northern sections of
the state. Again, this will come down to smaller details, so it
is advised that you stay tuned for later forecast updates