SPC AC 010612

   Day 2 Convective Outlook CORR 1
   NWS Storm Prediction Center Norman OK
   0112 AM CDT Sat Aug 01 2020

   Valid 021200Z - 031200Z

   ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM EASTERN PA
   INTO CENTRAL NY...

   CORRECTED FOR WIND PROBABILITY LINE

   ...SUMMARY...
   Severe thunderstorms capable of damaging wind, hail, and perhaps a
   couple of tornadoes will be possible over portions of the Northeast
   on Sunday.

   ...Synopsis...
   Minimal change to the large-scale pattern is expected on Sunday,
   with an upper trough remaining over much of the central/eastern
   CONUS, while an upper ridge persists over most of the West. A
   midlevel shortwave trough and associated surface low in the lower
   Great Lakes vicinity at the start of the period are forecast to move
   northeastward into Quebec by Monday morning. T.C. Isaias is
   currently forecast by NHC to move very near the FL Space Coast by
   Sunday morning and then move nearly parallel to the coast for much
   of the period.

   ...Northeast...
   Moderate destabilization near and south of the surface warm front,
   combined with veering wind profiles with 35-50 kt of effective
   shear, will result in a conditionally favorable environment for
   supercells across much of central/eastern PA/NY and northern NJ by
   Sunday afternoon. However, substantial uncertainty remains regarding
   storm coverage across the region with the most favorable
   environment. Large-scale ascent associated with the departing
   shortwave trough is expected to primarily remain north of the
   international border, with a capping inversion around 700 mb
   potentially limiting deep convection across much of the warm sector.

   At least isolated thunderstorm development will be possible along an
   eastward-moving surface trough Sunday afternoon. All hazards would
   be possible with any sustained deep convection. A Slight Risk has
   been introduced from northeast PA into central NY, where confidence
   in storm coverage is somewhat greater due to potentially stronger
   heating and instability compared to areas further north and east. 

   ...Southeast WY...CO...NM...West TX...
   North-northwesterly midlevel flow on the east side of the upper
   ridge will again result in a broad region from southeast WY into
   CO/NM and west TX where effective shear will increase into the 30-45
   kt range by afternoon. Instability may be somewhat greater compared
   to Saturday, especially into the CO Front Range and adjacent High
   Plains where low-level easterly flow will advect 50s F dewpoints
   into the area. A few discrete supercells may develop by afternoon
   and move south-southeastward, while some loosely organized
   southward-moving clusters will also be possible, especially from
   southern CO into NM and west TX where storm coverage is expected to
   be somewhat greater. Hail and locally severe wind gusts will be the
   primary threats with this activity. 

   ...Florida...
   The current forecast track of Isaias very near the FL east coast
   would keep the most favorable tornado environment offshore through
   the period, though any westward deviation and sustained landfall
   would bring the threat for a brief tornado or two inland. No
   probabilities have been included with this outlook, though any
   westward adjustment to the track would require the addition of at
   least 2% tornado probabilities in a subsequent update.

   ..Dean.. 08/01/2020

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