The Storm Prediction Center (SPC) 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 through a list of forecast statistics that identify areas at risk of mild thunderstorms and severe thunderstorms across the contiguous United State. 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 260559 SWODY1 SPC AC 260557 Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1257 AM CDT Sat Apr 26 2025 Valid 261200Z - 271200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FOR PARTS OF THE SOUTHERN HIGH PLAINS INTO THE ARKLATEX...AND ALSO FOR PART OF THE MID ATLANTIC AND CAROLINAS... ...SUMMARY... Strong to potentially severe storms are possible later today across parts of the southern High Plains into the ArkLaTex region, and also across parts of the Mid Atlantic and Carolinas. ...Synopsis... A deep mid/upper-level trough and embedded midlevel cyclone will move eastward into the Southwest later today, while another midlevel cyclone and related shortwave trough move southeastward from the Great Lakes into the Northeast. A surface cyclone attendant to the Northeast system will move eastward across New England, as a trailing cold front moves through the Mid Atlantic and Carolinas. ...NM into the Southern Plains and ArkLaTex... Extensive convection is expected overnight into the early part of the forecast period this morning, from the TX Panhandle/South Plains vicinity into southwest OK. Evolution of this convection and related outflow remains uncertain, though the majority of guidance suggests that an MCV will develop from this preceding convection and move eastward across OK through the day. Meanwhile, a cold front will move southward across OK during the morning, before stalling and beginning to move northward as a warm front later in the period. Storm intensification and/or redevelopment will be possible in the vicinity of the front during the afternoon, potentially aided by the eastward-moving MCV. Near/south of the front, relatively rich low-level moisture may support moderate destabilization by afternoon. Generally veering wind profiles are expected from parts of OK/north TX into the ArkLaTex, though the strength of low/midlevel flow and size/length of hodographs will depend on the vigor of any MCV that moves across the region. An organized severe threat with some threat for all severe hazards could develop if a well-defined MCV favorably interacts with returning low-level moisture near the front. The Marginal Risk has been expanded eastward in response to this potential scenario. Farther southwest, isolated to widely scattered diurnal storm development will be possible near the remnant outflow boundary somewhere across west/southwest TX, and also within the post-frontal regime closer to the higher terrain of NM/CO. Coverage of storms across these areas remains uncertain in the absence of stronger large-scale ascent, but isolated supercell development will again be possible, with at least a localized threat of large hail, strong/severe gusts, and possibly a tornado. Greater probabilities may be needed if confidence increases in locally greater supercell coverage across part of this region. ...Northeast/Mid Atlantic/Carolinas... Weak to moderate destabilization will be possible this afternoon across the Northeast/Mid Atlantic/Carolinas, and at least widely scattered storm development will be possible along/ahead of the advancing cold front. Gradually strengthening midlevel flow and deep-layer shear in response to the approaching mid/upper-level shortwave trough could support a few stronger cells/clusters during the afternoon and evening. The magnitude of diurnal heating and destabilization remains somewhat uncertain, but locally damaging wind and small to near-severe hail could accompany the strongest storms. ..Dean/Halbert.. 04/26/2025 $$ |
Convective Outlook Day 2
SPC Day 2 Outlook Discussion
ACUS02 KWNS 260602 SWODY2 SPC AC 260600 Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 0100 AM CDT Sat Apr 26 2025 Valid 271200Z - 281200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS MUCH OF CENTRAL AND NORTHWEST NEBRASKA...SOUTHERN SOUTH DAKOTA...AND FAR NORTHERN KANSAS.... ...SUMMARY... Isolated severe storms are possible across the southern High Plains and central Plains Sunday afternoon/evening. Scattered severe storms are possible across the northern Plains and Upper Midwest Sunday evening/night. ...Discussion... A moderately strong mid-level jet streak will extend from the Southwest and into the Central Plains on Sunday as a mid-level trough advances eastward through the Intermountain West. As this occurs, a strong surface cyclone will develop in the central High Plains/northern Plains. This strengthening cyclone will draw richer low-level moisture into the northern Plains while a dryline sharpens across the High Plains. This dryline will extend from southwest Nebraska southward to the Texas Big Bend on Sunday afternoon. Mid to upper 60s dewpoints east of this dryline and strong heating will support moderate to strong instability by Sunday afternoon. Forecast soundings show significant inhibition along the dryline in the southern High Plains with lesser inhibition with increasing latitude. Weak height falls and a sharp dryline circulation could support isolated supercell development along the dryline from southwest Kansas southward. A favorable environment will support a conditional threat for all severe weather hazards wherever supercells can develop within this region, but coverage concerns preclude a greater categorical risk at this time. Farther north, near the surface low, storm coverage probabilities increase due to stronger forcing and weaker inhibition. At least a few supercells are likely from northern Kansas across Nebraska and perhaps into far southern South Dakota Sunday evening with a threat for large hail and severe wind gusts. Hodographs will be relatively small during the evening, but once the low-level jet intensifies after 00Z, hodographs will enlarge quite rapidly with increasing low-level shear in the 00Z to 02Z timeframe. However, storm longevity and intensity after sunset remains questionable as forecast soundings show strong inhibition across much of the open warm sector. Therefore, any supercells which develop, may mostly exist prior to the strengthening low-level shear. Therefore, only 2 percent tornado probabilities are warranted at this time despite a considerably higher conditional threat. Scattered thunderstorms capable of large hail are expected to develop late Sunday evening and into the overnight hours along and north of the warm front as isentropic ascent strengthens with the associated strengthening low-level jet. ..Bentley.. 04/26/2025 $$ |
Convective Outlook Day 3
SPC Day 3 Outlook Discussion
ACUS03 KWNS 260742 SWODY3 SPC AC 260741 Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0241 AM CDT Sat Apr 26 2025 Valid 281200Z - 291200Z ...THERE IS A MODERATE RISK OF SEVERE THUNDERSTORMS FROM CENTRAL IOWA INTO SOUTHEAST MINNESOTA AND WESTERN WISCONSIN... ...SUMMARY... An outbreak of severe weather is likely across portions of the Midwest and Upper Midwest. Large hail, severe wind gusts, and strong to intense tornadoes are likely. ...A tornado outbreak with the potential for strong to intense tornadoes is possible on Monday... ...Midwest into the Upper Midwest... A strong mid-level jet streak will move rapidly northeastward from the Southwest to the Upper Midwest on Monday. As this occurs, a surface low will deepen and move from the northern Plains to the northern Great Lakes. Strong southwesterly lower tropospheric flow will advect high theta-e air northward across the Midwest and into parts of the Upper Midwest. Broken to scattered cloud cover will support surface heating and strong destabilization across the warm sector in Iowa and into southeast Minnesota and western Wisconsin. Severe storms may develop as early as mid-day across western Minnesota and western Iowa on the nose of a 70-80 knot mid-level jet streak. These storms may begin as supercells, but mode may become more linear as the cold front intersects the dryline across Minnesota during the afternoon. Even if mode is more linear, embedded tornadoes will be possible given the strengthening low-level shear. Farther south and east, a more discrete mode will be favored within a weakly capped warm sector. As lower tropospheric flow strengthens through the day, the warm sector will expand rapidly northeastward, creating a broad warm-sector featuring moderate to strong instability and very strong (60+ knots) shear. Increasing forcing during the afternoon should be sufficient to overcome weak capping across the warm sector. Therefore open warm sector supercells will be possible in addition to supercells along the eastward advancing dryline. Any supercells which can develop within this increasingly favorable environment Monday afternoon/evening will be capable of strong to intense tornadoes. By late evening, a squall line will likely overtake much of the discrete convection as the cold front advances rapidly southeast. Severe wind gusts and embedded tornadoes will remain possible through the late evening and perhaps into the overnight hours. ...Central/Southern Plains... A strongly unstable and strongly sheared warm sector will exist along and east of the dryline from eastern Kansas southward to West Texas. Forcing is much weaker than farther north with only weak height falls along the dryline. However, most guidance shows minimal inhibition along the dryline and at least isolated storm development, perhaps aided by some nocturnal low-level jet increase during the evening. Any supercells which develop will pose a threat for all severe hazards including the potential for strong tornadoes. ..Bentley.. 04/26/2025 $$ |
Convective Outlook Day 4-8
SPC Day 4-8 Outlook Discussion
ACUS48 KWNS 260849 SWOD48 SPC AC 260848 Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0348 AM CDT Sat Apr 26 2025 Valid 291200Z - 041200Z ...DISCUSSION... ...Day 4/Tuesday - West Texas to the Northeast... Moderate instability will be present along an elongated frontal zone from the southern Plains to the Northeast on Tuesday. Modest shear along the frontal zone will support some organization into multicell clusters and perhaps supercells. A greater severe weather threat will exist across the eastern Great Lakes where forcing and shear will be strongest as a 75 knot mid-level jet streak crosses southern Ontario. Another focused zone of greater coverage of severe storms will be across parts of West Texas where multiple rounds of storm are anticipated. The first chance of storms will be during the afternoon as the front continues to move south across Oklahoma and perhaps into North Texas. An additional round of storms will be possible across parts of West Texas as the low-level jet strengthens Tuesday night in the presence of strong instability and shear. ...Day 5/Wednesday - North Texas to the ArkLaTex... Ongoing Day 4 convection may have some impact on the exact location of the severe weather threat on Tuesday. However, regardless of Day 4 convective evolution, there will likely be a region with a more focused severe weather threat on Day 5/Wednesday where moderate to strong instability exists ahead of strengthening mid-level flow and a mid-level trough which will move across the southern Plains. 15% probabilities have been added for Day 5 from North Texas to the ArkLaTex where this location of greatest severe weather threat appears most likely at this time. ..Bentley.. 04/26/2025
Convective Weather Outlook Legend Data
- TSTM (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-ENH (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 or 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