May 16, 2019 1300 UTC Day 1 Convective Outlook
Updated: Thu May 16 12:53:44 UTC 2019 (20190516 1300Z Day 1 shapefile | 20190516 1300Z Day 1 KML)
Probabilistic to Categorical Outlook Conversion Table
Categorical Graphic
20190516 1300 UTC Day 1 Outlook Graphic
Day 1 Risk Area (sq. mi.) Area Pop. Some Larger Population Centers in Risk Area
SLIGHT 188,965 28,527,251 Chicago, IL...Indianapolis, IN...Milwaukee, WI...Toledo, OH...Cincinnati, OH...
MARGINAL 405,156 26,209,677 Detroit, MI...Columbus, OH...Cleveland, OH...Omaha, NE...Pittsburgh, PA...
Probabilistic Tornado Graphic
20190516 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
2 % 30,815 12,294,272 Chicago, IL...Fort Wayne, IN...Aurora, IL...Naperville, IL...Joliet, IL...
Probabilistic Damaging Wind Graphic
20190516 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
15 % 166,591 21,755,843 Chicago, IL...Indianapolis, IN...Milwaukee, WI...Fort Wayne, IN...Madison, WI...
5 % 401,383 27,077,419 Detroit, MI...Columbus, OH...Omaha, NE...Toledo, OH...Cincinnati, OH...
Probabilistic Large Hail Graphic
20190516 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
15 % 187,765 28,250,402 Chicago, IL...Indianapolis, IN...Milwaukee, WI...Toledo, OH...Cincinnati, OH...
5 % 308,539 23,405,626 Detroit, MI...Columbus, OH...Cleveland, OH...Omaha, NE...Pittsburgh, PA...
   SPC AC 161253

   Day 1 Convective Outlook  
   NWS Storm Prediction Center Norman OK
   0753 AM CDT Thu May 16 2019

   Valid 161300Z - 171200Z

   ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS THIS AFTERNOON
   INTO TONIGHT FROM EASTERN WY/NE/IA TO SOUTHERN LOWER MI AND WESTERN
   OH...

   ...SUMMARY...
   Severe storms are possible today and tonight from the central High
   Plains eastward into the Midwest region. Isolated strong to severe
   storms are also possible from southern Montana through northern
   Idaho during the afternoon, across portions of Utah and vicinity,
   and across parts of southeast New Mexico and West Texas.

   ...Synopsis...
   A surface cold front will move southeastward across the upper Great
   Lakes in conjunction with a northern stream shortwave trough
   crossing ON.  The western extent of this front is expected to stall
   across IA/NE in response to lee cyclogenesis across the central High
   Plains, in advance of deep midlevel trough crossing the Great Basin
   and approaching the central/southern Rockies overnight.

   ...Great Lakes/OH Valley through tonight...
   A cluster of elevated storms is ongoing over WI in a zone of strong
   low-level warm advection.  The surface warm sector will spread
   eastward today into IL/IN, possibly reaching southwest Lower MI by
   late afternoon.  Continuing warm advection will help maintain the
   ongoing storms, or contribute to new development later today into
   tonight.  The stronger storms will occur near the edge of the warm
   sector where the convection is rooted closest to the ground, and
   storms should be more elevated with eastward extent into OH tonight.
   An upstream feed of boundary-layer dewpoints in the low-mid 60s
   beneath the northeast edge of an elevated mixed layer plume will
   maintain moderate buoyancy, and vertical shear will favor organized
   clusters/some embedded supercells along the warm front.  Damaging
   winds and large hail can be expected with the storm clusters this
   afternoon into early tonight, and a tornado or two will also be
   possible this evening.

   ...NE/northern High Plains and northern Rockies this
   afternoon/evening...
   Easterly upslope flow will be maintained through the period on the
   cool side of the stalled front (just N of the lee cyclone), with the
   somewhat richer low-level moisture/buoyancy confined mainly to NE. 
   Gradual height falls in advance of the expansive western trough will
   combine with the upslope flow and daytime heating in cloud breaks to
   support scattered thunderstorm development this afternoon, which
   will persist into this evening.  The storm environment will support
   a few high-based supercells capable of producing large hail and
   strong/damaging outflow gusts, with the greater threat closer to the
   NE Panhandle.  A similar environment/scenario will extend back into
   the northern Rockies of southwest MT and northern ID, along the
   northern influence of the Great Basin trough.  Overnight, elevated
   convection will persist across NE/IA in response to strengthening
   warm advection north of the front on the nose of a southwesterly
   low-level jet.  

   ...Parts of UT/ID this afternoon/evening...
   The zone of strongest forcing for ascent in advance of the midlevel
   trough and along the cold front will reach western UT and southern
   ID later this afternoon through this evening.  Though low-level
   moisture will be limited, weak buoyancy is expected ahead of the
   front.  Thunderstorms will be capable of producing isolated
   strong/damaging gusts in an environment characterized by weak
   buoyancy, steep low-level lapse rates, and strong deep-layer
   southerly shear.

   ...Southeast NM and southwest TX this afternoon/evening...
   The surface lee trough will sharpen today in response to increasing
   southwest flow aloft over the southern Rockies.  This area will lie
   along the northwest edge of the richer returning low-level moisture,
   which will likely be offset today by deep mixing.  Still, some
   increase in deep-layer shear and sufficient buoyancy suggest that a
   couple of high-based supercells will be possible immediately east of
   the high terrain in southeast NM into southwest TX late this
   afternoon/evening.  Marginally severe hail and strong outflow gusts
   will be the main threats.

   ..Thompson/Cook.. 05/16/2019

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