Jul 26, 2017 2000 UTC Day 1 Convective Outlook
Updated: Wed Jul 26 19:45:28 UTC 2017 (20170726 2000Z Day 1 shapefile | 20170726 2000Z Day 1 KML)
Probabilistic to Categorical Outlook Conversion Table
Categorical Graphic
20170726 2000 UTC Day 1 Outlook Graphic
Day 1 Risk Area (sq. mi.) Area Pop. Some Larger Population Centers in Risk Area
MARGINAL 284,010 25,796,319 Chicago, IL...Milwaukee, WI...Kansas City, MO...Colorado Springs, CO...Wichita, KS...
Probabilistic Tornado Graphic
20170726 2000 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
20170726 2000 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
5 % 283,818 25,782,206 Chicago, IL...Milwaukee, WI...Kansas City, MO...Colorado Springs, CO...Wichita, KS...
Probabilistic Large Hail Graphic
20170726 2000 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 261945

   Day 1 Convective Outlook  
   NWS Storm Prediction Center Norman OK
   0245 PM CDT Wed Jul 26 2017

   Valid 262000Z - 271200Z

   ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM SOUTHEAST
   CO TO IL...

   ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
   THE GREAT BASIN...

   ...SUMMARY...
   Isolated strong to severe wind gusts are possible late afternoon
   into this evening across parts of the Midwest and Great Basin.

   ...20z Update...

   Minor changes to severe probs are warranted for buoyancy starved
   regions of KS/MO/IA.

   A considerable amount of debris from Monday night convection has
   settled into a corridor from south-central KS into northern lower
   MI. Surface heating is reduced along this zone which is limiting
   buoyancy within an otherwise poor lapse rate environment. Severe
   probs have been lowered across portions of this region due to
   extensive cloud cover.

   ..Darrow.. 07/26/2017

   .PREV DISCUSSION... /ISSUED 1127 AM CDT Wed Jul 26 2017/

   ...Midwest...
   A broad swath of non-severe convection is ongoing from MI southwest
   to KS. While most of this convection appears to be steady-state to
   decaying, redevelopment persists in the warm-advection regime across
   north-central KS. In the downstream warm sector, regional 12Z
   soundings sampled weak 700-500 mb lapse rates of 5-6 degree C/km
   along with weak tropospheric winds. The net effect of these limiting
   factors will be to confine the areal extent and amplitude of
   afternoon destabilization, along with restraining the degree of
   intensification on the leading edge of broad-scale outflow. Sporadic
   wet microbursts appear to be the most likely scenario with a low
   chance for an organized MCS.

   ...South-central High Plains...
   Several CAMs are insistent on developing a couple multicell clusters
   off the higher terrain this evening. With weak low-level
   northeasterlies beneath modest mid/upper-level westerlies, this
   scenario may occur. Given relatively warm mid/upper-level
   temperatures limiting hail growth, the main hazard should be
   isolated strong to severe wind gusts.

   ...Great Basin...
   The persistent mid-level cyclone over northern CA will shift
   northeast into southeast OR by Thursday morning. Scattered storms
   will develop again across the Great Basin downstream of this wave, 
   with the pre-storm environment consisting of well-mixed
   thermodynamic profiles given full insolation already underway. With
   somewhat larger buoyancy expected compared to previous days amid
   25-30 kt effective shear, the setup should yield a risk for
   localized severe wind gusts.

   NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 0100Z