May 18, 2019 1730 UTC Day 2 Convective Outlook
Updated: Sat May 18 17:35:22 UTC 2019 (20190518 1730Z Day 2 shapefile | 20190518 1730Z Day 2 KML)
Probabilistic to Categorical Outlook Conversion Table
Categorical Graphic
20190518 1730 UTC Day 2 Outlook Graphic
Day 2 Risk Area (sq. mi.) Area Pop. Some Larger Population Centers in Risk Area
SLIGHT 224,972 49,038,713 Chicago, IL...Detroit, MI...Indianapolis, IN...Columbus, OH...Cleveland, OH...
MARGINAL 318,331 54,592,748 Philadelphia, PA...Memphis, TN...Baltimore, MD...Milwaukee, WI...Washington, DC...
Probabilistic Graphic
20190518 1730 UTC Day Probabilitic Graphic
Probability of severe weather within 25 miles of a point.
Hatched Area: 10% or greater probability of significant severe within 25 miles of a point.
Day 2 Prob. Risk Area (sq. mi.) Area Pop. Some Larger Population Centers in Risk Area
15 % 224,764 49,047,643 Chicago, IL...Detroit, MI...Indianapolis, IN...Columbus, OH...Cleveland, OH...
5 % 318,368 53,506,918 Philadelphia, PA...Memphis, TN...Baltimore, MD...Milwaukee, WI...Washington, DC...
   SPC AC 181735

   Day 2 Convective Outlook  
   NWS Storm Prediction Center Norman OK
   1235 PM CDT Sat May 18 2019

   Valid 191200Z - 201200Z

   ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF
   THE GREAT LAKES AND THE OHIO VALLEY...EAST ACROSS PA/NY AND
   VICINITY...

   ...SUMMARY...
   Thunderstorms capable of damaging wind gusts and hail are expected
   across portions of the Great Lakes/Ohio Valley area and east across
   the Appalachians.  Less widespread severe risk will be possible
   across the Mid and Lower Mississippi and Tennessee Valleys during
   the day, and possibly evolving over the southern High Plains late in
   the period.

   ...Synopsis...
   As a large upper low/trough digs southeastward out of the eastern
   Pacific into the western U.S. this period, a second trough is
   forecast to shift northeastward across the Great Lakes/Ohio Valley
   region through the period.

   At the surface, a cold front associated with the eastern trough will
   likewise cross the Great Lakes/Ohio Valley, but will become
   elongated east-west on its southern fringe later in the period, from
   the lower Mississippi Valley westward into the southern Plains. 
   This front, and the associated upper system, will be a primary
   contributor to the severe risk across the eastern U.S. Sunday.

   ...Lower Michigan and the Ohio Valley area eastward into the
   Northeast...
   Remnant/weakening convection is expected across western portions of
   the SLGT risk area at the start of the period, which will to some
   degree influence the degree of later heating/ destabilization in
   some areas.  At this time, it would appear that remnant convection
   may reintensify during the afternoon over the Ohio vicinity, while
   new storms develop near the front as it crosses
   Illinois/Indiana/lower Michigan.  With moderately strong deep-layer
   west-southwesterlies expected across the entire area, fast-moving
   bands of storms should evolve, capable of locally damaging winds --
   and possibly hail.  

   Farther east -- into parts of PA and NY, storms may develop within
   more weakly forced, but destabilizing environment from the
   mountains, eastward.  With deep-layer wind field amply strong,
   storms here should also intensify locally, becoming capable of
   producing locally damaging winds and hail.  While these storms
   should diminish through the evening, storms advancing eastward
   across the Ohio Valley may remain strong enough to bring an
   additional, limited severe risk into PA/NY during the evening.

   ...Tennessee/Mid and Lower Mississippi Valleys...
   Uncertainty exists across the region, with convection likely
   ongoing/moving eastward across portions of the risk area at the
   start of the period -- possibly accompanied by limited severe risk. 
   It would appear at this time that convection should reach a minimum
   in terms of coverage and intensity through late morning, while
   destabilization of the moist boundary layer near the southern and
   eastern fringe of -- and possibly in the wake of -- the earlier
   convection should occur.  This destabilization should support
   reintensification of storms, and perhaps new storm development near
   and ahead of the advancing surface front.  While shear will weaken
   with southward extent, local severe risk will likely exist with
   stronger afternoon storms.  At this time, will maintain only MRGL
   risk, but some potential for SLGT risk upgrade over parts of the
   area could be required, as evolution of the early/ongoing convection
   and its potential effect on later-day storms becomes more clear.

   ...Southern High Plains...
   As a low-level jet develops over the Southern High Plains overnight
   ahead of the advancing upper system, the increasingly strong QG
   ascent should lead to convective development late in the period
   (early Monday morning).  With storms expected to be elevated,
   primary severe risk would be hail with a couple of the strongest
   storms.

   ...MAXIMUM RISK BY HAZARD...
   Tornado:   5%     - Slight
   Wind:     15%     - Slight
   Hail:     15%     - Slight

   ..Goss.. 05/18/2019

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   NOTE: THE NEXT DAY 2 OUTLOOK IS SCHEDULED BY 0600Z