Subj : DAY1SVR: Day 1 Convective Outlook To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Wed May 10 2023 19:54:41 ACUS01 KWNS 101954 SWODY1 SPC AC 101952 Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0252 PM CDT Wed May 10 2023 Valid 102000Z - 111200Z ....THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS NORTHEAST COLORADO INTO FAR SOUTHWEST NEBRASKA AND FAR NORTHWEST KANSAS... ....SUMMARY... Scattered severe thunderstorms capable of producing tornadoes, large to very large hail, and severe wind gusts remain likely this afternoon and evening along the High Plains. Additionally, more isolated strong to severe thunderstorms are possible tonight across east Texas and western Louisiana. ....Front Range/High Plains... The forecast remains on track based on recent observations and trends in hi-res guidance. 5% tornado probabilities were expanded slightly across northwest KS where a few cumulus clusters have shown notable vertical development within a recovering boundary layer (where easterly surface winds are enhancing low-level helicity). A significant wind area is introduced for portions of southeast CO into adjacent areas of NM, OK, and KS, where dewpoint depressions over 40 F are noted ahead of developing convection within the higher terrain. These trends suggest the environment is favorable for efficient downward momentum transfer within stronger downdrafts that may result in a couple of 75+ mph gusts. For additional near-term trends, see MCD #754. ....North Dakota... The Marginal area has been extended slightly westward across parts of north-central ND to better align with recent surface and satellite observations, which depict shallow cumulus development along a diffuse surface trough. A few recent runs of hi-res guidance suggest a storm or two may develop within this regime, and modified forecast sounding indicate that locations with temperatures/dewpoints in the mid 70s/upper 50s may feature sufficient buoyancy for effective bulk shear values approaching 30 knots. ...Moore/Leitman.. 05/10/2023 ..PREV DISCUSSION... /ISSUED 1135 AM CDT Wed May 10 2023/ ....Front Range/High Plains... An east/northeastward-moving upper trough over Arizona and preceding upper jet exit region will influence the High Plains with a meridional flow pattern into this afternoon and tonight. A lee cyclone will persist over eastern Colorado and the Raton Mesa vicinity with a warm front extending east across northwest Kansas to southeast Nebraska, with the southern High Plains dryline mixing east into a portion of west Texas. A plume of 50s F surface dew points will be maintained to the north of the aforementioned central High Plains front amid persistent easterlies in the lowest 1 km. As large-scale ascent preceding the upper trough overspreads the central to southern Rockies and adjacent High Plains, initial convection will develop over the higher terrain by early afternoon. This activity will spread north-northeastward and increase in coverage through early evening. Several supercells are likely along the Front Range from east-central WY to south-central CO with a primary threat of large hail. Potential will exist for a more intense/long-tracked supercell or two developing off the Palmer Divide towards the Denver metro area and South Platte Valley, where rather enlarged/elongated hodographs coupled with the steep mid-level lapse rate environment could support very large hail and tornadoes. A few slow-moving supercells should be sustained near the dryline/front intersection in the CO/KS/NE border area with a similar very large hail and tornado threat. ....Southern High Plains... While isolated severe wind/hail potential is possible during the late afternoon near the Raton Mesa vicinity, the bulk of severe potential is likely to be delayed until late evening/overnight after the dryline retreats west. This will yield increasing moisture timed with a strengthening low-level jet and greater mid-level DCVA ahead of the Arizona/New Mexico shortwave trough. With a more westerly component to mid-level flow, especially with southern extent, potential will exist for a few supercells capable of large hail and severe wind gusts across the Texas South Plains/Permian Basin. ....Southeast Texas/Louisiana... An MCV over east-central Texas should drift towards the ArkLaTex today. Regenerative, slow-moving deep convection is ongoing along the upper Texas Gulf Coast, with recent scattered development underway to the Louisiana coastal plain. A belt of enhanced low-level winds is consistently progged to spread from just off the Texas coast to the Sabine Valley by afternoon. This would yield enlargement to the low-level hodograph in an otherwise weak deep-layer shear regime. However, given the degree of ongoing convection, diurnal destabilization is expected to be muted. Therefore, some diurnal potential for transient low-level circulations is anticipated but its still unclear whether a more favorable brief tornado and isolated damaging wind corridor can develop. It is possible that the primary severe risk, but still on a relatively isolated basis, occurs late tonight as storms potentially redevelop across far eastern Texas into Louisiana. ....Far northern Minnesota/North Dakota... A low-amplitude shortwave impulse will move east atop the northern extent of the upper ridge near the international border through the afternoon/evening. With the northeast plume of steep mid-level lapse rates impinging on the area, MLCAPE of 500-1500 J/kg should be common from central North Dakota into northwest Minnesota. While the bulk of supercell development should be confined to southern Manitoba, multicell clustering may spread/develop across the international border this evening with a threat for isolated damaging wind and severe hail. $$ = = = To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM. --- SBBSecho 3.14-Linux * Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (1:2320/105) .