SPC AC 270548

   Day 1 Convective Outlook  
   NWS Storm Prediction Center Norman OK
   1148 PM CST Tue Nov 26 2019

   Valid 271200Z - 281200Z

   ...NO SEVERE THUNDERSTORM AREAS FORECAST...

   ...SUMMARY...
   Isolated thunderstorms may occur today across parts of the Great
   Lakes, Northeast, and Mid-Atlantic, as well as portions of the
   Southeast and California. Severe thunderstorms appear unlikely.

   ...Great Lakes to Southern New England...
   A mature cyclone with a very strong mid/upper-level jet will move
   eastward over the Northeast and Mid-Atlantic today. At the surface,
   a low initially over southern WI and adjacent Lake Michigan will
   develop east-northeastward into southern Ontario/Quebec by this
   evening. A cold front attendant to this surface low will move
   eastward across the OH Valley, Mid-Atlantic, and Northeast through
   the day, reaching the Atlantic Coast by late this evening. Low-level
   moisture return ahead of the front will likely remain too meager to
   support surface-based storms, although there may be just enough
   elevated instability to result in charge separation and isolated
   lightning flashes.

   ...Southeast...
   Storms will likely be ongoing at the start of the period along and
   just ahead of the cold front across parts of the Southeast. This
   convection should quickly weaken through the morning as it becomes
   increasingly displaced to the south of large-scale ascent associated
   with the upper trough/low, and as low-level winds gradually
   diminish. The cold front will continue southeastward across this
   region later this afternoon, but poor mid-level lapse rates and
   minimal large-scale ascent should limit the potential for
   thunderstorms with eastward extent.

   ...California...
   An intense surface low moving onshore along the OR/CA border will
   gradually fill today as a large-scale upper low slowly weakens over
   the West Coast. Isolated thunderstorms may form in a post-frontal
   regime beneath this upper low across parts of CA as cold mid-level
   temperatures and steep lapse rates will be present. Lift associated
   with a westerly mid-level jet may focus thunderstorm activity over
   parts of central CA. Regardless, instability and shear are expected
   to remain quite weak. 

   ...Southwest to the Southern Plains...
   Persistent southwesterly flow aloft will encourage a modest increase
   in low and mid-level moisture across parts of the Southwest late
   tonight. The potential for lightning across southern AZ appears too
   low to include a general thunderstorm area at this time.

   Similarly, some low-level moisture return above a near-surface
   stable layer is also forecast across parts of the southern Plains
   late tonight as a southerly low-level jet modestly strengthens.
   While an elevated thunderstorm or two cannot be completely ruled
   out, the probability of occurrence appears too conditional to
   include an area for now.

   ..Gleason/Nauslar.. 11/27/2019

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