Severe Storm Outlook Narrative (AC)
Issued by NWS
ACUS02 KWNS 250541
SPC AC 250540
Day 2 Convective Outlook
NWS Storm Prediction Center Norman OK
1240 AM CDT Sat Mar 25 2017
Valid 261200Z - 271200Z
...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ON SUNDAY
AFTERNOON AND EVENING OVER PARTS OF CENTRAL OKLAHOMA AND NORTH
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER PARTS OF THE
...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS OVER PARTS OF
THE SOUTHERN PLAINS...
...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS OVER PORTIONS OF
THE SOUTHERN AND CENTRAL APPALACHIANS...
Severe thunderstorms capable of large hail, damaging winds, and a
tornado or two will be possible in parts of the southern Plains on
Sunday. Isolated strong wind gusts and hail may also occur in parts
of the southern and central Appalachians on Sunday.
The current water vapor loop shows a deepening upper trough
approaching southern CA. This feature will move across the southern
Rockies on Saturday before emerging into the southern Plains on
Sunday. Models have been quite consistent with the timing and
position of this feature, lending confidence in a focused severe
weather event on Sunday over parts of OK and north TX.
By afternoon, a surface low is expected to be positioned over
northwest OK, with a dryline extending southward into western North
TX. Thunderstorms are likely to develop along the dryline during
the mid-late afternoon and track east-northeastward across a rather
narrow warm sector. Forecast soundings from several 00z models
indicate steep mid-level lapse rates and surface dewpoints in the
upper 50s to around 60F. Forecast hodographs appear favorable for
discrete supercells capable of large hail and damaging winds, as
well as tornadoes. However, limited low-level moisture may prove to
be a negative factor for a more substantial tornado event. Given
the narrow corridor of instability, confidence in the eastward
progress of the severe threat into AR is low at this time.
...Southern and Central Appalachians...
A shortwave trough currently over the central Plains will track only
slowly eastward and still be affecting the eastern states on Sunday.
A consensus of 00z model solutions suggest a corridor of at least
marginal CAPE will develop on Sunday afternoon from northern AL/GA
into WV and southeast OH. Forecast soundings suggest relatively
cool mid level temperatures and strong winds aloft. These
parameters would support a risk of hail and gusty/damaging winds in
the stronger cells that form. The risk of severe storms should
diminish around sunset.