Storm Prediction Center - Day 1 Outlook

Data From the SPC

Day 1 Graphical Outlook

Definition: The probability values represent the chance of severe weather occurring within 25 miles of any point, which is approximately the size of a major metropolitan area.

Day 1 & 2: The outlook contains individual severe probabilities for tornadoes, wind, and hail.
Day 3: Due to greater uncertainty, the outlook only forecasts the combined probability of all three types of severe weather.

Context: Probabilities for severe thunderstorm wind and hail are typically higher than for tornadoes because they are more common. A 15% probability for a tornado means significantly above normal odds of a tornado nearby, which should be taken seriously, even though the number seems low.

Note: The peak daily tornado probabilities in the most tornado prone portions of the country (Plains and Southeast) are slightly above 2%. Therefore, most days with any tornado probabilities are well above climatology.


SPC Category Descriptions (Click image to enlarge)



Issue Times

Day 2 Outlook

Day 1 Outlook Discussion

SPC AC 110057

   Day 1 Convective Outlook  
   NWS Storm Prediction Center Norman OK
   0757 PM CDT Sat Oct 10 2026

   Valid 110100Z - 111200Z

   ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
   THE CAROLINAS AND DESERT SOUTHWEST...

   ...SUMMARY...
   Thunderstorms associated with an isolated tornado threat will be
   possible this evening across parts of the Carolinas. A few severe
   wind gusts will also be possible in parts of the Desert Southwest.

   ...Carolinas...
   The remnants of Isaias will continue to move northward across the
   Tennessee Valley this evening. In the eastern part of the system,
   scattered convection with little lightning activity is currently
   ongoing from eastern Georgia northward into the western Carolinas.
   This convection is located along and near the axis of a low-level
   jet. Surface analysis has dewpoints over much of eastern Georgia and
   southern South Carolina in the 70s F. Within this moist airmass, the
   RAP has MLCAPE in the 1000 to 1500 J/kg range. In addition, the
   latest WSR-88D VWP at Columbia, South Carolina has a looped
   hodograph with 0-3 km storm-relative helicity near 500 m2/s2. This
   strong low-level shear will support a tornado threat this evening
   into the overnight with rotating cells that remain semi-discrete,
   mainly across the eastern half of South Carolina into southern North
   Carolina.

   ...Desert Southwest...
   Tropical Storm Rachel, in conjunction with a mid-level shortwave
   trough, will move toward the northern part of Baja California this
   evening. Ahead of the system, moisture advection will continue
   across parts of the Desert Southwest. Over southwestern Arizona,
   surface dewpoints will continue to increase into the mid to upper
   60s F, aiding destabilization this evening with MLCAPE increasing to
   around 1000 J/kg. In addition, large-scale ascent will increase as
   the exit region of a mid-level jet overspreads the region. In
   response to the lift, scattered thunderstorms will likely develop
   and move northeastward across southern and western Arizona this
   evening. The mid-level jet will also create moderate to strong
   deep-layer shear sufficient for isolated severe storms. A few severe
   wind gusts will be possible.

   ..Broyles.. 10/11/2026

   CLICK TO GET WUUS01 PTSDY1 PRODUCT

   NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 0600Z

Issued by the Weather Prediction Center