Subj : DAY1SVR: Day 1 Convective Outlook To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Sun Apr 14 2024 12:48:38 ACUS01 KWNS 141248 SWODY1 SPC AC 141246 Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0746 AM CDT Sun Apr 14 2024 Valid 141300Z - 151200Z ....THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF EASTERN OHIO INTO PENNSYLVANIA... ....SUMMARY... Severe thunderstorms should develop late this afternoon in a narrow corridor across the upper Ohio Valley into Pennsylvania and vicinity. Damaging winds should be the main threat. Severe hail and perhaps a couple of tornadoes also appear possible as this activity spreads slowly southward into this evening. ....Ohio Valley into the Mid-Atlantic and Northeast... Early morning surface observations show a dearth of low-level moisture from the upper OH Valley into the Mid-Atlantic, with surface dewpoints generally in the 30s. However, boundary-layer moisture will gradually increase through the day across these regions, as a weak surface low migrates eastward from the Great Lakes across NY. By late afternoon, generally upper 40s to low 50s surface dewpoints should become focused in a narrow corridor along and south of front from OH into PA and southern NY. With upper troughing persisting over eastern Canada and parts of the Northeast, generally westerly mid-level winds across the Midwest/OH Valley will aid in the eastward advection of an EML and associated steep mid-level lapse rates. Even though low-level moisture is expected to remain limited, these steepened lapse rates aloft, along with diurnal heating, should encourage the development of weak to locally moderate MLCAPE late this afternoon. Surface-based thunderstorm initiation across this region will likely be delayed until 20-21Z or later, as lingering MLCIN and a cap gradually erodes. Initial development should be focused along the front across parts of eastern OH into western/central PA, with additional development eventually occurring into eastern PA and parts of southern NY. Given strong deep-layer shear and favorable lapse rates, large hail may occur with the more robust cores initially. Some threat for a couple of tornadoes may also exist with semi-discrete convection, as sufficient low-level shear will be present for updraft rotation. But, with the surface front aligned mostly parallel to the enhanced westerly low/mid-level flow, upscale growth into small bowing clusters should quickly occur as convection spreads south-southeastward. Scattered damaging winds will likely become the main threat with these clusters through the early evening in a narrow spatial corridor extending from eastern OH into PA where instability and steep low/mid-level lapse rates should be maximized. The damaging wind threat will gradually decrease through the evening as instability lessens with southward/eastward extent. ...Gleason/Grams.. 04/14/2024 $$ = = = 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 3.20-Linux * Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (1:2320/105) .