SPC AC 311744

   Day 2 Convective Outlook  
   NWS Storm Prediction Center Norman OK
   1244 PM CDT Fri Mar 31 2023

   Valid 011200Z - 021200Z

   ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER MUCH OF THE
   NORTHEAST...AND OVER PARTS OF THE SOUTHEAST....

   ...SUMMARY...
   Damaging winds are expected across parts of the Northeast Saturday
   during the day and through early evening. Other severe storms will
   be possible over parts of the Southeast.

   ...Synopsis...
   A large shortwave-trough will move across the Upper Great Lakes and
   OH Valley to the Mid Atlantic by 00Z, with substantial height
   falls/cooling aloft overspread the entire region. An intense leading
   midlevel jet streak will approach the Appalachians by midday, with a
   secondary cold pocket and vort max aloft affecting the I-95 corridor
   late in the day. To the south, moderate westerlies aloft will exist
   over the Southeast, as the influence of the upper trough grazes the
   area.

   At the surface, low pressure should gradually deepen as it moves
   east/northeast from southwest Ontario toward northern ME. Extending
   east of the low track will be a developing warm front which will
   bring 50s F dewpoints into southern VT/NH and perhaps ME. 

   Although the primary surface low will move toward more stable areas
   to the north, a prominent surface trough will develop southward
   coincident with the secondary vort max moving rapidly east. While
   various regimes of severe weather may occur with these features,
   this secondary wave will affect the Mid Atlantic late in the day and
   into early evening, and is expected to result in wind damage from
   western MA and CT into far eastern PA, all of NJ, and parts of the
   Delmarva. A few tornadoes may occur over southern parts of this
   region.

   Farther south, a front/dryline will slow as it moves into southern
   AL and across GA during the day, with a more substantial cold front
   pushing east across VA and the Carolinas. Scattered severe storms
   are possible across these areas during the day.

   ...From eastern OH into New England...
   The initial severe risk on Saturday will likely be tied to the
   leading vort max associated with left-front quadrant of the midlevel
   jet. Cold temperatures aloft will result in 250-500 J/kg SBCAPE in
   the corridor from eastern OH/western PA across much of NY and into
   New England by late afternoon. The combination of very steep,
   deep-layer lapse rates along with increasing boundary-layer wind
   speeds suggest any convection at all will have the potential to
   enhance downward mixing. This seems likely given expected sufficient
   instability. The northward extent of this damaging wind regime will
   be limited by the warm front, and it is possible that this boundary
   eventually makes it into extreme southern ME.

   ...From the Delmarva across NJ and into southern New England...
   Southerly surface winds for most of the day will help deepen the
   moist boundary layer, with a plume of upper 50s F to near 60 F
   dewpoints from eastern VA northward across Philadelphia and into far
   southeast NY. Strong heating will occur along and west of this moist
   plume, priming the air mass for the arrival of an intense cold front
   arrive very late in the day and into early evening for eastern
   areas. Forecast soundings reveal supercell wind profiles with
   effective SRH over 300 m2/s2, and long hodographs as well. The
   forecast is for storms to form in the moist axis as the front
   rapidly intercepts the moist air mass, with rapid changes taking
   place aloft. Some of these storms could develop along coastal
   counties as well, and at least isolated supercells are expected. A
   conditional tornado risk will exist where SBCAPE remains favorable,
   centered over NJ and DE. Damaging winds will be quite likely with
   any strong convection given 50+ kt winds out of the northwest just
   off the surface. Clearly, these will be able to mix to the surface.
   Various models appear to be struggling with this area, thus there is
   uncertainty in the magnitude of the severe risk. 

   ...Southern GA into the eastern Carolinas...
   Scattered showers and a few thunderstorms may be ongoing ahead of
   the surface boundary early in the day, beneath southwesterly 50 kt
   850 mb flow and within a theta-e plume. Strong heating is expected
   near the synoptic boundary and deepening surface trough, and the
   presence of mid 60s F dewpoints will lead to ample instability to
   support daytime storms despite lack of upper support. With time,
   storms along the boundary may develop into supercells as deep-layer
   shear will be strong and effective SRH averages 150-200 m2/s2. Any
   supercell/tornado threat is expected to be limited as midlevel
   subsidence occurs, but sporadic hail, a brief tornado, and damaging
   gusts will all be possible through the afternoon. Rapid drying from
   the west should push the severe threat quickly eastward across the
   region and to the eastern Carolinas before 00Z.

   ..Jewell.. 03/31/2023

   CLICK TO GET WUUS02 PTSDY2 PRODUCT

   NOTE: THE NEXT DAY 2 OUTLOOK IS SCHEDULED BY 0600Z