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acus02 kwns 241713
swody2
Storm Prediction Center ac 241711
Day 2 convective outlook
National Weather Service Storm Prediction Center Norman OK
1211 PM CDT Friday may 24 2013
Valid 251200z - 261200z
..there is a slight risk of severe thunderstorms across the northern and Central
High plains...
..nrn/Central High plains...
Early morning short-wave trough is expected to rotate northward across southern
ab/sk and weak height rises are anticipated across the northern rockies
in its wake. Even so a broad zone of middle level southwesterly flow on the
order of 30-40kt should extend across the Great Basin into the
northern/Central High plains through the period. This broad zone of modest
deep layer shear is expected to support several clusters of
organized thunderstorm activity...initially forming within upslope regions
along Lee trough...then possibly modulated by low level jet after dark.
Boundary layer moisture is expected to advance northward across the High
Plains as Lee trough becomes firmly established downstream of western
U.S. Upper trough. Surface dew points in the 50s should advect across
the western Dakotas into eastern Montana where 2km deep Ely low level winds will
veer into the SW at middle levels. Forecast sounding for mls at 23/00z
depicts modest instability...SBCAPE of 2800 j/kg...and strong shear
supportive of supercells. Other soundings across the High Plains
exhibit these characteristics favorable for sustained rotating
updrafts. Although no discernible disturbances are forecast to
affect the High Plains during the afternoon it appears strong
diurnal heating will weaken the cap such that orographic forcing
should lead to thunderstorm development by late afternoon. Large hail is
likely with any supercell that evolves across this region and
isolated tornadoes are also possible.
..ern nm/West Texas...
Much weaker deep layer flow is forecast across the southern rockies where
500 mb flow may struggle to maintain 20kt into eastern nm. As across
the northern/Central High plains...strong heating near the Lee trough will
prove instrumental in afternoon thunderstorm development. A few
storms may produce hail/wind across this region but with weaker
shear the likelihood for meaningful organization is considerably
less than points north.
.Darrow.. 05/24/2013
