Severe Storm Outlook Narrative (AC)
Issued by NWS
Issued by NWS
988 ACUS02 KWNS 261731 SWODY2 SPC AC 261729 Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1229 PM CDT Sun May 26 2024 Valid 271200Z - 281200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM THE MID-ATLANTIC INTO THE SOUTHEAST... ...SUMMARY... Severe thunderstorms are possible from the Mid Atlantic to the Southeast Monday into Monday night, with severe wind, hail and potentially a tornado or two expected. ...Synopsis... A strong (sub 1000mb) surface low will exist near Lower Michigan Monday morning. This surface low will deepen through the day as it moves northeast of Lake Superior by the evening. A cold front will extend from this surface low across western Lake Erie to the Mid-Mississippi Valley at 12Z and cross the Appalachians by 00Z. Strong to severe thunderstorms are possible along and ahead of this cold front during the afternoon into the evening hours. This cold front will stall near the Gulf Coast and back into northern Texas. A dryline will retreat westward during the day as weak lee troughing and strengthening southwesterly flow advects low-level moisture westward. ...Mid-Atlantic into North Carolina... A decaying MCS will likely result in cloud cover across this region Monday morning. However, some clearing is expected by late morning to early afternoon. Convective temperatures near 80F should be met by early afternoon with scattered thunderstorm development ahead of the cold front. Effective shear between 30 and 35 knots will support both multicell and supercell clusters. Thermodynamically the best environment should be across Virginia and North Carolina. However, stronger flow across eastern Pennsylvania may be more supportive of supercells and thus a greater hail threat despite the weaker thermodynamics. In addition, RAP forecast soundings show low-level shear supportive of a tornado or two across most of the warm sector from North Carolina into eastern Pennsylvania and the Delmarva. ...Southeast... There is considerable uncertainty regarding the expected overnight MCS and how it may impact severe weather across Alabama, Georgia, and South Carolina on Monday. Most forecast soundings show significant inhibition which would support CAM solutions which show the MCS decaying during the morning. Strong westerly flow and an EML may allow for recovery in the wake of any morning MCS with a threat for storms along the cold front during the afternoon as temperatures warm into the 80s to near 90 and strong instability develops. Large hail and damaging wind gusts will be the primary threat with this activity. A lack of convergence along the front and weaker large-scale ascent should result in more sparse storm development farther west along the front through MS and LA during the afternoon/evening. ...Texas and southwest Oklahoma... Moisture will recover northwest through the day south of a stalled front as a result of strengthening southwesterly flow. As boundary layer moisture deepens from southeast to northwest through the day, a few storms may develop as the airmass becomes uncapped. Forcing should be quite nebulous which will keep storm coverage isolated, but environmentally, extreme (5000+ J/kg) MLCAPE and effective shear over 60 knots would support a conditional threat for large to very large hail and potentially a tornado. The best chance for storm development will likely be across northwest Texas during the late evening as the low-level jet strengthens and low-level moisture advection and isentropic ascent increases. ...Midwest... Storms are expected to develop from southern Minnesota and move quickly southeast across Iowa and into Illinois Monday afternoon/early evening amid cold air advection aloft and sufficient remnant moisture for 500-1000 J/kg MLCAPE. Strong unidirectional westerly flow may support some stronger downdrafts capable of wind damage. ..Bentley.. 05/26/2024 $$