588 

ACUS01 KWNS 200507

SWODY1

SPC AC 200505



Day 1 Convective Outlook  

NWS Storm Prediction Center Norman OK

1205 AM CDT Wed May 20 2026



Valid 201200Z - 211200Z



...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF

WEST TEXAS...



...SUMMARY...

Scattered severe storms with large hail and isolated severe gusts

are expected today across parts of west Texas. A few storms with

isolated severe gusts and hail will also be possible from the

central Appalachians into the Mid-Atlantic and far southern New

England.



...Southern High Plains...

Southwesterly mid-level flow will remain in place today over the

south-central U.S. At the surface, a quasi-stationary front will be

positioned from west Texas eastward into the Texas Hill Country.

South of the front, surface dewpoints in the 70s F will result in an

axis of moderate instability. The strongest instability is forecast

to develop from the lower Rio Grande River Valley

north-northwestward into far west Texas and eastern new Mexico. As

instability increases during the day and low-level convergence

becomes focused along the front, scattered thunderstorms are

expected to develop across far west Texas. These storms will move

eastward into west-central Texas by early to mid evening. Additional

storms may develop further north-northwest into eastern New Mexico.



RAP forecast soundings along the instability axis in the late

afternoon from Fort Stockton northward to Midland have MLCAPE near

2000 J/kg. 0-6 km is forecast to be around 50 knots with 700-500 mb

lapse rate from 7 to 8 C/km. This environment will be favorable for

supercells with large hail. The more dominant storms will have

potential for hailstones greater than 2 inches in diameter. Isolated

severe wind gusts will also be possible. A more isolated severe

threat may also develop further north-northwest across the southern

High Plains along the instability axis.



...Central Appalachians/Mid-Atlantic/Far Southern New England...

West-southwesterly mid-level flow will be in place today across much

of the eastern U.S. At the surface, a cold front will advance

southward across the central Appalachians and Mid-Atlantic. To the

south of the front, surface dewpoints in the upper 60s F will enable

an axis of moderate instability to develop by afternoon. MLCAPE is

forecast to peak in the 1000 to 2000 J/kg range in most areas ahead

of the front. Increasing low-level convergence near the front will

lead to scattered thunderstorm development during the afternoon.

These storms will move eastward across the central Appalachians,

Mid-Atlantic and far southern New England. RAP forecast soundings at

21Z along and near the instability axis have 0-6 km shear up to 25

knots with steep low-level lapse rates. This should support a severe

threat with multicell storms. Isolated severe wind gusts and hail

will be possible. The severe threat may persist into the early

evening.



..Broyles/Squitieri.. 05/20/2026



$$