Severe Weather outlook
Storm Prediction Center
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SPC Jun 15, 2025 0730 UTC Day 3 Severe Thunderstorm Outlook
SPC 0730Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0223 AM CDT Sun Jun 15 2025 Valid 171200Z - 181200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE CENTRAL PLAINS AND LOWER TO MID MISSOURI VALLEY... ...SUMMARY... Thunderstorms with an isolated large hail and wind-damage threat will be possible on Tuesday across parts of the central Plains and lower to mid Missouri Valley. Outside of this area, marginally severe storms may develop over parts of the central U.S. An isolated severe threat is also expected across parts of the Central Appalachians and Mid-Atlantic. ...Great Plains/Lower to Mid Missouri Valley/Mid to Upper Mississippi Valley... At mid-levels, a shortwave trough is forecast to move into the Rockies on Tuesday, as a ridge remains in place over the southern Plains. At the surface, a cold front will advance southward through the central U.S., likely reaching southern Kansas, northwest Missouri and southeast Iowa by afternoon. To the south of the front, surface dewpoints in the lower to mid 70s F will contribute to moderate to strong instability across much of this moist airmass by afternoon. As low-level convergence increases, convection is expected to initiate along and near the front, with scattered strong to severe thunderstorms moving southeastward toward the instability axis in the late afternoon and early evening. Model forecasts suggest that an impressive thermodynamic environment will be in place ahead of the front by Tuesday afternoon. From 21Z to 00Z, NAM forecast soundings along parts of the instability axis have MLCAPE peaking between 4000 and 5000 J/kg. Moderate deep-layer shear is also forecast, mostly due to speed shear in the mid-levels. This environment should support supercells with large hail, especially early in the event when storms are more likely be discrete. A wind-damage threat is also expected to develop as storms congeal, and as a line gradually organizes. The severe threat should persist through much of the evening, with MCS development possible. Further northwest into parts of the central High Plains, upslope easterly flow is forecast within a post-frontal airmass. Surface dewpoints will be mostly in the 50s F. As surface temperatures warm during the day, pockets of moderate instability are expected to develop over parts of the region. Thunderstorms are expected to initiate in the higher terrain during the early to mid afternoon, with storms moving eastward into the lower elevations. Steep mid-level lapse rates and moderate deep-layer shear should be sufficient for a marginal severe threat. ...Central Appalachians/Mid-Atlantic... At mid-levels, a subtle shortwave trough is forecast to move eastward across the southern and central Appalachians on Tuesday. Ahead of this feature, a very moist airmass will be in place with surface dewpoints in the lower to mid 70s F over much of the Atlantic Coastal Plain. By afternoon, moderate instability is expected to develop within most of this airmass. Convection will initiate in the higher terrain of the Appalachians, and move eastward into the lower elevations during the afternoon. Moderate deep-layer shear and steep low-level lapse rates, evident on forecast soundings, will contribute to a marginal wind-damage threat. ..Broyles.. 06/15/2025
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SPC Jun 15, 2025 Day 4-8 Severe Weather Outlook
Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0359 AM CDT Sun Jun 15 2025 Valid 181200Z - 231200Z ...DISCUSSION... ...Wednesday/Day 4 and Thursday/Day 5... A mid-level trough is forecast to move through the Upper Midwest on Wednesday, as a cold front advances southeastward into the lower Missouri and mid-Mississippi Valleys. Ahead of the front, moderate instability is forecast to develop by afternoon. Thunderstorms appear likely to form along parts of the front, with several clusters or line segments moving eastward toward the instability axis during the late afternoon and early evening. Moderate deep-layer shear should support severe storms with large hail and wind damage as the primary threats. The mid-level trough is forecast to move into the lower Great Lakes and upper Ohio Valley on Thursday, as the cold front advances into the central Appalachians. As the airmass ahead of the front destabilizes, scattered thunderstorms are expected to form along and ahead of the front. The models suggest that moderate deep-layer shear will be in place across much of the northeastern U.S., which will likely support organized storms. Damaging winds gusts will be the most likely severe threat. ...Friday/Day 6 to Sunday/Day 8... A shortwave mid-level ridge is forecast to move into the upper Mississippi Valley on Friday. The ridge is forecast to remain over the region on Saturday as mid-level heights rise. Beneath the ridge, a moist and unstable airmass will likely be in place from the lower to mid Missouri Valley northeastward into the western Great Lakes. Within this airmass, isolated thunderstorm development should take place both Friday and Saturday afternoon. Instability and deep-layer shear appear sufficient for a localized severe threat. However, the presence of the ridge introduces uncertainty as to where the greatest potential for convection will be. For this reason, predictability is low. On Sunday, a mid-level trough is forecast to develop over the Rockies as a ridge moves into the Great Lakes region. Although a moist and unstable airmass should be located over parts of the northern and eastern U.S., large-scale ascent and mid-level flow is forecast to be relatively weak in most areas. For this reason, any severe potential is expected to remain isolated.
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