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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



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