SPC Aug 2, 2020 0600 UTC Day 1 Convective Outlook

SPC 1200Z Day 1 Outlook
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Day 1 Convective Outlook NWS Storm Prediction Center Norman OK
Scattered strong storms, a few possibly severe, will be noted across
the Northeast later today. Damaging winds are the primary threat. ...Northeast... Weak mid-level disturbance will eject across the lower Great Lakes
ahead of the main upper trough positioned farther west over the MS
Valley. This lead feature should encourage a weak surface low to
track from southern ON into southwest QC by mid evening. Any
appreciable mid-level height falls will remain north of the
international border, along with the primary large-scale mass
response. Early in the day1 period, deep convection will likely be ongoing
within a corridor of low-level warm advection, along the nose of a
pronounced LLJ. This LLJ will shift north across upstate NY into
southern ON/QC during the afternoon hours as a surface warm front
advances north of the border. At this time it appears the primary
focus for sustained, organized deep convection will be noted
immediately ahead of the surface low. Latest model guidance suggests
strong boundary-layer heating will occur ahead of the surface low
across western NY where temperatures should warm rapidly through the
mid 80s. Renewed surface-based convection should evolve in the lee
of Lake Ontario then track northeast. If the surface warm front were
to be delayed advancing north into QC, low-level shear would be
improved markedly across northern NY which would prove more
supportive for supercells and tornadoes. Additionally, there is also
some concern for strong convection along the trailing warm front
that extends southeast across the Hudson Valley. While
boundary-layer warming may not be as strong/focused as farther
north, sustained warm advection and high PW-airmass should result in
scattered strong convection. Forecast wind profiles favor some
supercell threat, though clustering is also possible. Damaging winds
should be the primary concern. Farther south, a belt of seasonally strong mid-level flow will
extend from the base of the trough over the southern Appalachians
into the northern Middle Atlantic. While neutral/weak height rises
are expected across this region, boundary-layer heating and
orographic influences should encourage at least isolated
thunderstorms. While poor lapse rates will limit convective updraft
strength with this activity, modest cloud-layer flow should allow
for some organization, along with a threat for localized wind
damage. ...Central/Southern Rockies Region... Modest 500mb flow along the front side of the southwestern US ridge
will continue across the central/southern Rockies through the day1
period. Scattered convection has developed regularly during the
afternoon hours across the higher terrain, and this will occur again
later this afternoon. Isolated damaging winds remain the greatest
risk with this diurnally driven convection. ..Darrow/Wendt.. 08/02/2020 

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