SPC AC 161919

   Day 1 Convective Outlook  
   NWS Storm Prediction Center Norman OK
   0119 PM CST Fri Nov 16 2018

   Valid 162000Z - 171200Z

   ...NO THUNDERSTORM AREAS FORECAST...

   ...SUMMARY...
   No thunderstorms are forecast across the U.S. through tonight.

   ...Discussion...
   No change has been made to the previous outlook.

   ..Smith.. 11/16/2018

   .PREV DISCUSSION... /ISSUED 1005 AM CST Fri Nov 16 2018/

   ...Discussion...
   Downstream of blocking within the mid-latitude westerlies over the
   eastern Pacific, mid/upper flow across much of the U.S., while not
   particularly amplified, appears likely to remain broadly confluent
   and cyclonic.  

   Strongest mid-level height falls, associated with a pair of vigorous
   short wave perturbations within this regime, are in the process of
   spreading from southeastern Canada and the Northeast toward the
   northwestern Atlantic.  As this continues, an associated deepening
   surface cyclone is forecast to migrate northeast of Cape Cod into
   areas near/east of the Canadian Maritimes.  A cold front trailing
   from this feature has already advanced well south/east of the Gulf
   and Atlantic coasts, including the Florida Straits.

   In the wake of the front, cold surface ridging remains a prominent
   influence across much of the Gulf of Mexico and Gulf Coast region. 
   While the center of this ridge may shift from the north central Gulf
   coast into the vicinity of the central Appalachians by early
   Saturday, a significant reinforcing cold intrusion is expected to
   nose southeastward to the lee of the northern Rockies.  

   In response to these developments, generally stable conditions will
   prevail across the U.S., with negligible (less than 10 percent) risk
   for thunderstorm activity.

   ...Northern New England coast...
   Models do suggest that strong differential thermal advection and
   forcing for ascent at mid-levels may contribute to a corridor of
   weak destabilization near coastal Downeast Maine early this
   afternoon.  Forecast soundings indicate that moist parcels
   contributing to weak CAPE will be based near/above 700 mb, where
   thermal profiles will generally be entirely below freezing, and the
   risk for charge separation supportive of lightning appears
   negligible.

   ...Northern Intermountain region/Rockies...
   Beneath strong mid-level cooling, insolation may contribute to weak
   boundary layer destabilization across the mountains of central Idaho
   and Wyoming through the Black Hills vicinity by late this afternoon.
   This may support scattered low-topped convective development, but
   forecast soundings suggest that the potential for charge separation
   supportive of lightning is negligible.

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