Nov 19, 2021 1300 UTC Day 1 Convective Outlook
Updated: Fri Nov 19 12:38:44 UTC 2021 (20211119 1300Z Day 1 shapefile | 20211119 1300Z Day 1 KML)
Probabilistic to Categorical Outlook Conversion Table
Categorical Graphic
20211119 1300 UTC Day 1 Outlook Graphic
Day 1 Risk Area (sq. mi.) Area Pop. Some Larger Population Centers in Risk Area
No Risk Areas Forecast
Probabilistic Tornado Graphic
20211119 1300 UTC Day 1 Tornado Probabilities Graphic
Probability of a tornado within 25 miles of a point.
Hatched Area: 10% or greater probability of EF2 - EF5 tornadoes within 25 miles of a point.
Day 1 Tornado Risk Area (sq. mi.) Area Pop. Some Larger Population Centers in Risk Area
No Risk Areas Forecast
Probabilistic Damaging Wind Graphic
20211119 1300 UTC Day 1 Damaging Wind Probabilities Graphic
Probability of damaging thunderstorm winds or wind gusts of 50 knots or higher within 25 miles of a point.
Hatched Area: 10% of greater probability of wind gusts 65 knots or greater within 25 miles of a point.
Day 1 Wind Risk Area (sq. mi.) Area Pop. Some Larger Population Centers in Risk Area
No Risk Areas Forecast
Probabilistic Large Hail Graphic
20211119 1300 UTC Day 1 Large Hail Probabilities Graphic
Probability of hail 1" or larger within 25 miles of a point.
Hatched Area: 10% or greater probability of hail 2" or larger within 25 miles of a point.
Day 1 Hail Risk Area (sq. mi.) Area Pop. Some Larger Population Centers in Risk Area
No Risk Areas Forecast
   SPC AC 191238

   Day 1 Convective Outlook  
   NWS Storm Prediction Center Norman OK
   0638 AM CST Fri Nov 19 2021

   Valid 191300Z - 201200Z

   ...NO SEVERE THUNDERSTORM AREAS FORECAST...

   ...SUMMARY...
   The risk for thunderstorms appears negligible across most of the
   U.S. today through tonight.

   ...Synopsis/Discussion...
   In mid/upper levels, a nearly zonal large-scale pattern will
   predominate over the CONUS thus period, punctuated by two principal
   perturbations: 
   1.  A synoptic-scale trough initially extending the length of QC,
   then south-southwestward over the central Appalachians.  This
   feature will move eastward and deamplify slightly, clearing the
   Mid-Atlantic around local midday and Maine this evening.
   2.  A pronounced, positively tilted shortwave trough -- apparent in
   moisture-channel imagery across the Olympic Peninsula and
   southwestward over the Pacific to about 300 nm west of the coastal
   OR/CA line.  This feature will move inland to the Canadian Rockies,
   eastern OR and northwestern CA by 00Z, then extending over the
   Yellowstone to RNO areas by 12Z.  Because of lack of greater
   low-level moisture/theta-e, inland lightning potential with this
   system (if any) will be too isolated, brief and conditional for a
   thunder-outlook area. 

   At the surface, a slow-moving cold front was analyzed at 11Z from
   Atlantic waters off the Carolinas, southwestward over central FL, to
   the central Gulf.  This front should weaken slowly and decelerate
   further over central/south-central FL through tonight.  To its
   south, rich low-level moisture with seasonally large PW (generally
   1.75-2 inches in 12Z observed and model forecast soundings) will
   offset modest deep-layer lapse rates, in support of around 700-1200
   J/kg MLCAPE south of the front, with weak MLCINH.  This, along with
   the lack of low-level and deep shear, will promote showers and
   sporadic thunderstorms in poorly organized, discrete to clustered,
   multicellular modes.  Though a diurnal peak in convective potential
   is expected, at least isolated thunderstorms also may move inland
   from the Straits anytime during the period.  Heavy rainfall is the
   main concern -- see WPC excessive-rain outlooks for more on that
   threat.

   ..Edwards/Jewell.. 11/19/2021

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   NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 1630Z