SPC AC 181727
Day 2 Convective Outlook
NWS Storm Prediction Center Norman OK
1227 PM CDT Sat Aug 18 2018
Valid 191200Z - 201200Z
...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM OKLAHOMA
AND PARTS OF NORTH TEXAS EASTWARD THROUGH ARKANSAS AND THE OZARKS...
A few severe storms will be possible mainly Sunday afternoon and
evening over parts of the southern Great Plains, Ozarks, and
With stronger flow aloft confined to Canada Sunday, a relatively
weaker flow regime will prevail across the CONUS. Within this flow
field however, three areas of troughing are evident. Two -- one
departing the East and a second moving into/across the Pacific
Northwest -- will contribute to areas of convection, but very little
However, limited/low-end severe risk may accompany the third feature
-- a trough crossing the Great Plains region. This trough will
contribute to weak surface cyclogenesis -- with a weak low center
initially in the vicinity of Oklahoma shifting slowly northeast
across southeast Kansas and eventually into western Missouri. As
this low develops, a cool front will progress southward across
Oklahoma and the High Plains of Texas, while a warm front shifts
north across the Mid-Mississippi/Tennessee/lower Ohio Valleys later
in the period.
Elsewhere, a trailing cold front -- associated with an upper trough
crossing central Canada -- is expected to move across the northern
Plains/upper Mississippi Valley region through the period, with
showers and a few thunderstorms likely accompanying.
...Oklahoma/north Texas east through Arkansas and the Ozarks...
An ongoing -- though largely disorganized -- cluster of
thunderstorms is forecast to be crossing the Great Plains region at
the start of the period, ahead of the advancing upper trough. While
small hail and gusty winds may be possible with a few of the
stronger early-day updrafts -- particularly across the Oklahoma
vicinity -- storms should remain largely sub-severe.
Though weak cyclogenesis will likely occur through the day,
lingering clouds/convection will result largely in weak lapse rates
as well as some hindrance with respect to daytime heating.
Therefore, although a belt of enhanced (40 kt) westerly mid-level
flow will spread across this region, convective intensity -- and
thus severe risk -- should remain limited. Some redevelopment of
storms near the leading edge of the remnant convection/possible MCV
may occur over eastern Oklahoma and into the Ozarks vicinity, while
some heating in the wake of the convection may allow a few cells to
develop over southern Kansas and northern/western Oklahoma. While
gusty winds and marginal hail may occur with a few stronger
updrafts, overall risk appears likely to remain quite limited
through the period.
...MAXIMUM RISK BY HAZARD...
Tornado: 2% - Marginal
Wind: 5% - Marginal
Hail: 5% - Marginal
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NOTE: THE NEXT DAY 2 OUTLOOK IS SCHEDULED BY 0600Z