SPC AC 161930
Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0130 PM CST Thu Nov 16 2017
Valid 162000Z - 171200Z
...NO SEVERE THUNDERSTORM AREAS FORECAST...
Severe storms are not expected across the contiguous United States
Little change was made to the previous outlook, as thunderstorm
chances across the Lower 48 remain minimal.
.PREV DISCUSSION... /ISSUED 1005 AM CST Thu Nov 16 2017/
Shortwave trough currently moving through western PA/NY will
continue eastward through the early afternoon before pivoting
northeastward across southern New England as it matures and becomes
more vertically stacked with a deepening surface low currently
centered just south of Long Island. As this surface low deepens,
strengthening low/mid-level flow will contribute to strong warm-air
advection and resulting low-level frontogenesis across southern New
England. This mesoscale forcing for ascent coupled with increased
large-scale forcing for ascent resulting from the approaching
shortwave (currently evidenced by the line of low-topped convection
moving across central Long Island/CT) will result in a few updrafts
deep enough to support lightning this afternoon.
Farther west, mid-level temperatures will continue to cool
throughout the day as an upper trough progresses through the region.
Resultant steep lapse rates and modest instability will support
occasional lightning later this afternoon and evening within the
shallow, multi-cellular convection traversing the region.
A few lightning strikes are also possible within the shallow
convection occurring amidst the moist return flow across southeast
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