SPC Jun 1, 2023 0600 UTC Day 2 Convective Outlook

LIVE MAP (ABOVE) ... SPC 0600Z Day 2 Outlook Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1230 AM CDT Thu Jun 01 2023 Valid 021200Z - 031200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF WESTERN TEXAS... ...SUMMARY... Strong to severe thunderstorms capable of producing large hail, strong gusts and a couple of tornadoes are possible Friday afternoon and evening across parts of the southern High Plains. ...Southern Plains vicinity... A midlevel shortwave trough will shift east across the southern Plains on Friday. As this occurs, 500 mb temperatures cooling to around -10 to -12 C, resulting in steepening midlevel lapse rates, will overspread western portions of Texas into western OK. A belt of enhanced west/southwesterly midlevel flow associated with this feature, atop southeasterly low-level flow, will create favorable vertically veering wind profiles, with 40+ kt effective-shear magnitudes supporting supercell structures. Southeasterly low-level flow will allow for low/mid 60s F dewpoints as far west as the TX/NM border along a surface trough. Strong heating, especially from the Big Bend toward the South Plains vicinity, will support a corridor of strong destabilization by afternoon (2000-3000 J/kg MLCAPE). A mix of discrete supercells and organized clusters is expected by late afternoon and continuing into the evening. Elongated hodographs, in the presence of steep midlevel lapse rates/large CAPE, and favorable midlevel shear suggest large to very large hail will be possible, especially with more discrete convection. Steep low-level lapse rates and modest low-level shear also will support strong downburst winds. Damaging-wind potential may increase toward evening as some guidance suggests a bowing MCS could develop eastward across the Slight risk (level 2 of 5) area. This evolution is a bit uncertain, given a lack of a strong low-level jet response in most forecast guidance. However, if a strong-enough cold pool in generated, some upscale development seems plausible during the evening. While low-level shear will generally be modest, some augmentation to strength of low-level shear is possible near a surface low developing near the NM/TX border. Increased 0-3 km SRH along this corridor will support a relative max in tornado potential. Vertical shear will weaken with northward extent into OK and KS, and strong large-scale ascent will remain focused over west TX. This may limit longevity of more intense/organized cells developing during the late afternoon with northward extent. Nevertheless, moderate instability/shear will still support isolated strong/severe storms from western OK into southern KS. ...Northeast... Generally weak deep-layer northerly flow will persist across the region on the eastern periphery of a Great Lakes upper anticyclone. Some modest midlevel cooling and weak ascent associated with an approaching shortwave trough from Quebec, in combination with seasonal moisture/instability will support isolated thunderstorms during the afternoon. Vertical shear will remain very weak, limiting longevity and organization of strong updrafts. Nevertheless, steep midlevel lapse rates and well mixed boundary-layer could foster a few strong gusts and small hail in stronger cells. ..Leitman.. 06/01/2023 Read more CHECK UPDATE ZOOM GRAPHIC
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SPC Jun 1, 2023 0600 UTC Day 1 Convective Outlook

LIVE MAP (ABOVE) ... SPC 1200Z Day 1 Outlook Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1245 AM CDT Thu Jun 01 2023 Valid 011200Z - 021200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FOR THE TEXAS SOUTH PLAINS... ...SUMMARY... Strong to severe thunderstorms capable of producing hail, isolated severe gusts, and perhaps a tornado or two are possible across portions of the southern High Plains this afternoon and evening. ...Synopsis... An upper-level trough/low now over Arizona on water-vapor imagery will continue into the Four Corners today. This feature is expected to weaken during the day. Moderate mid-level winds will exist across the southern High Plains. At the surface, ongoing precipitation Wednesday evening into Thursday morning across the Texas Panhandle should leave an outflow boundary in the vicinity of the South Plains. With the approach of the trough, a modest surface trough will develop in eastern New Mexico, helping to maintain moisture influx into the region. ...Southern High Plains... An area of precipitation is expected to continue into Thursday morning in the Texas Panhandle. Outflow from this activity should provide some focus for thunderstorm development by late morning/afternoon. Precipitation is also occurring in the Trans-Pecos due to weak mid-level ascent in the region. This activity could impact the overall convective evolution today, though most guidance has this activity diminishing before Thursday morning. Guidance is in reasonable agreement with the location of the outflow boundary, but there are differences in the timing of convective initiation. With a weak shortwave moving into the area, there is some potential for storms to form by late morning. This would have some impact on the degree of destabilization that can occur. Even with this uncertainty, steep mid-level lapse rates and sufficient shear (30-35 kts effective) would support supercells capable of primarily large hail, isolated damaging winds and perhaps a tornado or two. The environment appears to support very large hail with supercells, though this would be more favored with initiation later in the day. The tornado threat will similarly be modulated by time of initiation, but also the degree of destabilization within the outflow to the north. ...Northern High Plains... A weak shortwave trough will move into the region along with a surface low developing in eastern Montana. Scattered convection will develop within a modestly unstable (1000-1500 J/kg MLCAPE) environment. Flow aloft will be generally weak. Gusty winds and small hail will be possible. Coverage of severe-caliber storms still appears too limited for unconditional probabilities. ..Wendt/Kerr.. 06/01/2023 Read more CHECK UPDATE ZOOM GRAPHIC
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SPC May 30, 2023 0600 UTC Day 1 Convective Outlook

LIVE MAP (ABOVE) ... SPC 1200Z Day 1 Outlook Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1256 AM CDT Tue May 30 2023 Valid 301200Z - 311200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FOR PORTIONS OF THE CENTRAL HIGH PLAINS... ...SUMMARY... Widely scattered severe thunderstorms capable of 60-80 mph gusts and large hail are possible over portions of the central High Plains late this afternoon through the evening. ...Central Great Plains... Isolated to widely scattered showers/thunderstorms may be ongoing early this morning before likely dissipating by mid morning over NE/KS. An MCV associated with this early day convection may focus at least isolated storm development during the afternoon into the early evening over the lower MO Valley. Isolated severe gusts may accompany the pulse-like thunderstorms. Farther west, a weak mid-level disturbance is forecast to move generally east from the CO Rockies to the CO/KS border by mid evening. Initially isolated storms are forecast to develop near the Cheyenne Ridge and east of the Front Range by mid afternoon. Strong heating through mid-late afternoon will result in very steep lapse rates (8.5 deg C/km in the surface-300 mb layer). As this activity moves into slightly richer moisture (surface dewpoints in the 50s), a broken linear cluster is forecast to develop (CAM guidance consensus agrees with this notion) from southwest NE/northeast CO southward to the TX/OK Panhandles. Forecast soundings show slightly stronger mid- to high-level westerly flow from I-70 northward, which may aid in hail potential and severe-gust potential. Significant severe gusts are possible during the early phase of the loosely organized squall line. By late evening, the risk for severe gusts will likely have diminished as the gust front/cold pool become less organized as the MCS moves towards central KS/northwest OK. ...Upper MS Valley... A mid-level short-wave trough initially over the Dakotas will move east into MN during the day. Isolated to scattered thunderstorms are forecast to develop near a weak surface trough by mid afternoon. With some enhancement to the mid-level west-southwesterlies associated with the upper system, a few stronger/sustained storms are expected to evolve with large hail being the primary threat. This potential should peak through late afternoon, and then diminish through the evening. ..Smith/Wendt.. 05/30/2023 Read more CHECK UPDATE ZOOM GRAPHIC
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SPC May 24, 2023 Day 4-8 Severe Weather Outlook

LIVE MAP (ABOVE) ... Day 4-8 Outlook Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0353 AM CDT Wed May 24 2023 Valid 271200Z - 011200Z ...DISCUSSION... Medium-range guidance is in good agreement that a Rex Block will be in place over the eastern CONUS D4/Saturday morning. This blocking pattern will likely remain in place through the early next week when the upper low moves off the Southeast coast. During this same time frame, an upper low is forecast to drift slowly southeastward/eastward across the Great Basin. Low-level moisture is expected to remain in place over the Plains and the relatively stagnant upper pattern should allow for a somewhat repetitive scenario of afternoon thunderstorm development across the High Plains. This will result in a broad area of at least low severe potential across the High Plains through the weekend and into early next week. Smaller areas of greater severe potential may become apparent/more predicable as the forecast range decreases. Read more CHECK UPDATE ZOOM GRAPHIC
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