Apr 27, 2017 1630 UTC Day 1 Convective Outlook
Updated: Thu Apr 27 16:27:51 UTC 2017 (20170427 1630Z Day 1 shapefile | 20170427 1630Z Day 1 KML)
Probabilistic to Categorical Outlook Conversion Table
Categorical Graphic
20170427 1630 UTC Day 1 Outlook Graphic
Day 1 Risk Area (sq. mi.) Area Pop. Some Larger Population Centers in Risk Area
SLIGHT 28,891 4,016,734 Columbus, GA...Columbia, SC...Macon, GA...Warner Robins, GA...Redan, GA...
MARGINAL 245,679 33,266,487 Charlotte, NC...Cleveland, OH...Atlanta, GA...Pittsburgh, PA...Buffalo, NY...
Probabilistic Tornado Graphic
20170427 1630 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
2 % 37,231 6,994,018 Charlotte, NC...Columbus, GA...Columbia, SC...Macon, GA...Gastonia, NC...
Probabilistic Damaging Wind Graphic
20170427 1630 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
15 % 28,150 3,821,510 Columbus, GA...Columbia, SC...Macon, GA...Warner Robins, GA...Redan, GA...
5 % 246,993 33,775,582 Charlotte, NC...Cleveland, OH...Atlanta, GA...Pittsburgh, PA...Buffalo, NY...
Probabilistic Large Hail Graphic
20170427 1630 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
5 % 89,416 4,353,825 Columbus, GA...Columbia, SC...Macon, GA...Warner Robins, GA...Enid, OK...
   SPC AC 271627

   Day 1 Convective Outlook  
   NWS Storm Prediction Center Norman OK
   1127 AM CDT Thu Apr 27 2017

   Valid 271630Z - 281200Z

   ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER PARTS OF
   AL...GA...AND SC...

   ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS OVER MUCH OF THE
   EASTERN UNITED STATES...

   ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS OVER PARTS OF
   THE CENTRAL HIGH PLAINS...

   ...SUMMARY...
   A few intense storms capable of damaging winds and perhaps hail or a
   tornado will be possible over parts of Georgia and South Carolina. 
   Otherwise, isolated severe wind gusts may accompany thunderstorms
   from portions of the Great Lakes region to the Southeast States
   today into this evening, and across portions of the central and
   southern Great Plains late this afternoon into this evening.

   ...GA/SC...
   An ongoing band of strong thunderstorms continues to occasionally
   show low/mid level rotation and indications of severe threat.  This
   scenario will likely continue through the afternoon as more storms
   form eastward across central GA and eventually into western SC. 
   Local VAD profiles and forecast soundings suggest that low/deep
   layer shear is favorable for organized thunderstorms including
   supercells and bowing structures.  Continued daytime heating and
   destabilization along the southern fringe of cloud cover across the
   risk area would support an upgrade to SLGT risk.  Locally damaging
   wind gusts are probably the main threat in the strongest cells. 
   However, an isolated tornado or two, along with some hail, is
   possible.

   ...OH/PA/NY/WV/VA...
   The latest surface analysis shows a cold front sweeping eastward
   across Lower MI and western OH. Only broken cloud cover ahead of the
   front is helping surface temperatures to climb through the mid 70s,
   resulting in steep low-level lapse rates and marginal instability.
   12z CAM solutions are relatively consistent that scattered showers
   and thunderstorm development this afternoon along/ahead of the front
   from eastern OH into much of WV and western PA.  The storms will
   eventually spread into central PA/VA and western MD this evening. 
   Strongly considered an upgrade to SLGT over parts of this corridor. 
   However, forecast soundings suggest very little CAPE and mid-level
   lapse rate only in the 6.0 C/km range.  It is likely that a few
   fast-moving showers and thunderstorms will pose a risk of
   gusty/damaging wind gusts this afternoon.  This region will be
   re-evaluated for an upgrade to SLGT at 20z.

   ...CO/KS/OK/TX...
   A few high-based thunderstorms are expected this afternoon and early
   evening over parts of southeast CO, southwest KS, and portions of
   the TX/OK Panhandles.  Instability will be quite limited.  However,
   steep mid level lapse rates and favorable wind fields suggest some
   risk of hail and gusty winds in the strongest cells.

   ..Hart/Mosier.. 04/27/2017

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   NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 2000Z