Probability of damaging thunderstorm winds or wind gusts of 50 knots or higher within 25 miles of a point. Hatched Area: 10% of greater probability of wind gusts 65 knots or greater within 25 miles of a point.
SPC AC 270056
Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0756 PM CDT Fri May 26 2017
Valid 270100Z - 271200Z
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF
THE CENTRAL HIGH PLAINS...
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
THE OHIO VALLEY...
...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM
SOUTHEASTERN WYOMING TO THE OZARKS...
...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM CENTRAL
ILLINOIS TO NORTHERN KENTUCKY...
Widely scattered thunderstorms with hail and damaging gusts will
continue this evening over parts of the central high Plains.
Overnight, isolated strong/severe storms may develop over parts of
the Ozark Plateau. Farther east, severe storms capable of damaging
winds, large hail, and a brief tornado will continue this evening
into the early overnight across parts of the Ohio Valley.
Strong to severe convection has organized across the high Plains of
eastern Colorado and southeastern Wyoming this evening, with large
hail and damaging winds being the primary severe hazards so far.
Within a regime of modest east/southeasterly surface flow and steep
mid-level lapse rates (as sampled by the 00Z DDC sounding), these
cells will likely continue east/southeast through the evening into
the early overnight, with a persisting threat for large hail,
damaging winds, and perhaps a brief tornado. Uncertainty exists with
regards to the eastward extent of this severe threat, as convective
inhibition increases slightly across central Kansas. However, any
semi-discrete/embedded rotating updrafts and/or strong cold pools
from upscale growth may supply enough forced ascent such that
vigorous updrafts are sustained across central Kansas. Furthermore,
an amplifying southerly low-level jet may further support convective
maintenance. As such, the Marginal Risk is expanded eastward.
Although considerable uncertainty exists regarding development of
deep convection late tonight, multiple large-scale and hi-res models
suggest a few thunderstorms are possible after approximately 05Z.
This scenario does not appear unreasonable, as an impulse noted in
water-vapor imagery over the southern high Plains will approach the
region overnight. Therefore, as forcing for ascent increases,
mid-level inhibition (noted in the 00Z SGF sounding) may weaken
sufficiently overnight, allowing for isolated/widely scattered
convection. Considering ample effective shear and steep mid-level
lapse rates, the potential exists for large hail and damaging winds
with any stronger core. Additionally, if parcels can become rooted
at the surface, a non-zero tornado threat would be present. The
Marginal Risk is expanded eastward to account for this conditional
severe threat late tonight.
Ongoing vigorous convection has transitioned into a more linear mode
over Indiana this evening, with a broad precipitation shield to its
northeast. While deep-layer shear remains strong, parcel buoyancy
wanes with eastward extent into Ohio (observed in the 00Z ILN
sounding). Therefore, propagation into higher buoyancy to the south
may drive stronger convection more southward towards far northern
Kentucky, with an attendant threat of damaging winds and large hail.
NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 0600Z