The Storm Prediction Center convective weather outlook is part of the National Weather Service (NWS) and the National Center for Environmental Prediction (NCEP). Their mission is to provide accurate forecasts and monitor the timing of thunderstorms and severe storms in the United States. The SPC provides convective outlooks on Day 1, Day 2, and Day 3 that reflect the overall level of severe weather hazard outlooks through a list of forecast statistics. This data identifies areas at risk of mild thunderstorms and severe thunderstorms. For more information on how to read this map, please see the bottom of this page.
Convective Outlook Day 1
SPC Day 1 Outlook Discussion
ACUS01 KWNS 182006 SWODY1 SPC AC 182005 Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0305 PM CDT Sat Apr 18 2026 Valid 182000Z - 191200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS WITHIN THE CENTRAL APPALACHIANS INTO THE UPPER OHIO VALLEY VICINITY...AND PARTS OF CENTRAL TEXAS... ...SUMMARY... Isolated marginally severe hail is possible in portions of central Texas. Isolated damaging winds remain possible from the central Appalachians into the Upper Ohio Valley vicinity. ...20Z Update... Based on observational trends 15% wind probabilities were removed from the Upper Ohio Valley vicinity. Wind gusts along with weak, shallow convection (with little lightning) have generally been in the 30 kt range with isolated cases of low 40 kt gusts. Isolated wind damage remains possible, but a more organized threat is not expected given weak buoyancy downstream. Elsewhere, marginally severe hail remains possible with isolated, elevated convection in central Texas. ..Wendt.. 04/18/2026 .PREV DISCUSSION... /ISSUED 1103 AM CDT Sat Apr 18 2026/ ...Upper OH Valley... Latest surface analysis shows a cold front pushing eastward across western OH, associated with a band of widespread clouds and light precipitation. Mostly clear skies are present ahead of the front, where temperatures are warming through the 70s. This will lead to a corridor of marginal afternoon instability and the potential for scattered thunderstorm intensification along the front. Forecast soundings show strong mid-level winds and steep low-level lapse rates, supportive of strong downdrafts in any vigorous convection. However, CAM guidance is consistent in showing very few organized/strong storms through the day. Will maintain the SLGT risk for the conditional risk of a few damaging wind events, but with limited confidence. ...TX... Isolated intense thunderstorms have been ongoing this morning in the post-frontal regime across central TX. These storms have produced hail and gusty winds for several hours. It appears likely that this scenario will shift eastward and weaken early this afternoon as the primary upper jet moves into AR and away from the region, but will maintain the MRGL risk area for a few more hours and extend it into parts of AR/LA. $$ |
Convective Outlook Day 2
SPC Day 2 Outlook Discussion
ACUS02 KWNS 181724 SWODY2 SPC AC 181723 Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1223 PM CDT Sat Apr 18 2026 Valid 191200Z - 201200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Severe thunderstorms are not expected on Sunday. ...Discussion... An amplified midlevel trough will move eastward from the Great Lakes into the Northeast on Sunday, while a related cold front moves off the Eastern Seaboard and the FL Peninsula. Preceding the trough, large-scale ascent will support isolated/elevated thunderstorms across coastal New England into the afternoon. Similarly, a couple thunderstorms are possible ahead of the front over coastal NC and farther south over the central/southern FL Peninsula (aided by an Atlantic sea breeze), though much of this activity may develop offshore. Farther west over the lower Great Lakes, lapse rates will quickly steepen beneath the core of the midlevel trough, and sufficient (albeit weak) buoyancy will support a couple thunderstorms -- given increasing ascent in the left-exit region of a midlevel jet. Finally, isolated/elevated thunderstorms will be possible within a post-frontal air mass across southwest TX, where weak warm-air advection will develop amid modestly steep midlevel lapse rates. ..Weinman.. 04/18/2026 $$ |
Convective Outlook Day 3
SPC Day 3 Outlook Discussion
ACUS03 KWNS 181916 SWODY3 SPC AC 181915 Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0215 PM CDT Sat Apr 18 2026 Valid 201200Z - 211200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Severe storms are not expected on Monday. ...Discussion... A midlevel trough will move from the Northeast off the New England coast on Monday, while the tail end of a related cold front continues southward into the Caribbean Sea. North of the front in southern FL, diurnal heating amid a moist post-frontal air mass should support isolated to widely scattered thunderstorms, though weak buoyancy and limited large-scale forcing for ascent should limit the severe risk. Farther west, weak low-level warm advection and modest moisture return ahead of a low-amplitude midlevel impulse moving into south TX will support a couple rounds of isolated/elevated thunderstorms across southwest TX. Isolated thunderstorm potential could spread further north into central TX late in the period, though confidence in this scenario is currently low. Additional diurnal thunderstorms are possible across the Southwest as the midlevel moisture impinges on the region, with most of this activity expected over the higher terrain. ..Weinman.. 04/18/2026 $$ |
Convective Outlook Day 4-8
SPC Day 4-8 Outlook Discussion
ACUS48 KWNS 180742 SWOD48 SPC AC 180740 Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0240 AM CDT Sat Apr 18 2026 Valid 211200Z - 261200Z ...DISCUSSION... Initially dry conditions will keep the severe weather threat low on D4/Tuesday. As a mid-level trough traverses the Rockies on Monday, lee troughing will strengthen on D5/Wednesday. This will bring substantial moisture return across the Plains. Given the early stage moisture return, more than an isolated severe weather threat appears unlikely on D5. A more substantial severe weather threat is anticipated on Day 6/Thursday. The evolution of the mid-level trough still remains unclear, but an overall pattern featuring broad troughing across the southern/central Plains, moderate to strong instability, and a sharp dryline, could support at least isolated supercells Thursday afternoon/evening. Have added a 15% area from western/central Oklahoma into southern/eastern Kansas where the severe weather threat seems likely regardless of how exactly the mid-level pattern evolves. The uncertainties discussed for Day 6 become greater on Day 7 and beyond. Persistent troughing across the Plains and considerable instability suggest that severe weather is likely on Friday (and likely into the weekend). However, the progression of the mid-level trough and the associated surface features need to become more clear before a 15% area can be defined for these days. ..Bentley.. 04/18/2026
Convective Weather Outlook Legend Data
- TSTMÂ (light green) – General or non-severe thunderstorms – Delineates, to the right of a line, where a 10% or greater probability of thunderstorms is forecast during the valid period.
- 1-MRGL (dark green) – Marginal risk – An area of severe storms of either limited organization and longevity, or very low coverage and marginal intensity.
- 2-SLGT (yellow) – Slight risk – An area of organized severe storms, which is not widespread in coverage with varying levels of intensity.
- 3-ENHÂ (orange) – Enhanced risk – An area of greater (relative to Slight risk) severe storm coverage with varying levels of intensity.
- 4-MDT (red) – Moderate risk – An area where widespread severe weather with several tornadoes and/or numerous severe thunderstorms is likely, some of which should be intense. This risk is usually reserved for days with several supercells producing intense tornadoes and/or very large hail. Or an intense squall line with widespread damaging winds.
- 5-HIGH (magenta) – High risk – An area where a severe weather outbreak is expected from either numerous intense and long-tracked tornadoes. Also, a long-lived derecho-producing thunderstorm complex that produces hurricane-force wind gusts and widespread damage. This risk is reserved for when high confidence exists in widespread coverage of severe weather with embedded instances of extreme severe. (i.e., violent tornadoes or very damaging convective wind events).
This data is courtesy from the Storm Prediction Center