SPC AC 040520
Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1120 PM CST Fri Dec 03 2021
Valid 041200Z - 051200Z
...NO SEVERE THUNDERSTORM AREAS FORECAST...
Isolated thunderstorms are expected from the Arklatex to the
northern Gulf States.
...Arklatex to northern Gulf States...
Weak short-wave trough over northeast TX is forecast to advance
slowly across the lower MS Valley later today before ejecting into
the central Gulf States overnight. In its wake, broad short-wave
ridging is forecast across TX ahead of the Baja Peninsula upper
trough. This flow regime will result in moist warm sector holding
across much of eastern TX/lower MS Valley. With the weak short-wave
trough forecast to advance across the lower MS Valley, low-level
flow will veer a bit and deep-layer flow is forecast to actually be
seasonally weak, though cool at mid levels. While large-scale
forcing for ascent is not expected to contribute appreciably, weak
low-level warm advection should be the primary forcing mechanism for
elevated convection. Forecast soundings suggest parcels lifted near
850mb across the Arklatex could yield MUCAPE in excess of 1500 J/kg.
However, effective shear will be weak and NAM sounding at PRX around
20Z suggests only 10kt at 500 mb. While some elevated convection is
expected across this region, weak shear and short-wave ridging will
not prove particularly favorable for large hail. Cool mid-level
temperatures may contribute to small hail in the strongest updrafts,
but the probability for severe appears too low to warrant a risk
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