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.
Memphis, TN...Little Rock, AR...Evansville, IN...Murfreesboro, TN...Fort Smith, AR...
SPC AC 311957
Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0257 PM CDT Thu May 31 2018
Valid 312000Z - 011200Z
...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS LATE THIS
AFTERNOON AND EVENING ACROSS PARTS OF THE MIDDLE MISSISSIPPI INTO
THE LOWER OHIO VALLEYS...
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
THE NORTHERN ROCKIES AND NORTHERN PLAINS...
Additional strong thunderstorm activity, accompanied by a risk for
severe wind and hail, is expected across parts of southern Missouri
and northern Arkansas into the lower Ohio Valley and Tennessee
Valleys, as well as the northern High Plains and northern Rockies,
late this afternoon and evening.
...20Z Outlook Update...
Adjustments to categorical and severe probabilistic lines have been
made in a number of areas. This is mostly in an attempt to better
account for latest trends in destabilization, and impacts of
Strongest instability (thermodynamic profiles characterized by steep
mid-level lapse rates and large CAPE) remains present in a corridor
along/south of a convectively generated or enhanced boundary across
parts of southern Kentucky into southern Missouri, where a 40-50 kt
westerly 500 mb jet streak is contributing to strong vertical shear.
Perhaps aided mostly by forcing for ascent associated with
lower/mid tropospheric warm advection, it appears that another
organized mesoscale convective system could evolve and propagate
east/southeastward late this afternoon and evening accompanied by a
risk for potentially damaging wind gusts. Initial storm development
may include isolated supercells with primarily a severe hail threat,
but a tornado or two might not be out of the question.
For more specific information concerning ongoing or imminent severe
weather potential, please refer to the latest SPC mesoscale
discussions and watches.
.PREV DISCUSSION... /ISSUED 1128 AM CDT Thu May 31 2018/
...Ozarks into OH Valley...
Multiple clusters of severe storms are expected to affect this
region today, with the first currently producing damaging winds over
southeast IL. These storms are expected to track eastward across
southern IN and northern KY through much of the day. Ref MCD #584
and WW #136 for more information.
In the wake of the initial band of storms, visible satellite imagery
shows rapid clearing across southern MO. This will result in strong
heating, steepening low-level lapse rates, and destabilization
across this region by early afternoon. 12z models are consistent in
re-development of intense storms over this area as a weak shortwave
trough moves into the region from KS. The initial storms will
potentially be supercellular with the risk of very large hail and a
tornado or two. Storms should slowly organize and grow upscale as
outflows merge, with an eventual bowing complex producing damaging
winds expected to move across the ENH area through the evening.
...Northern Great Basin into Northern Rockies...
An active thunderstorm day is expected today from northeast NV and
eastern ID into much of MT. A large upper trough is moving across
CA, with large scale lift and strong winds aloft spreading across
the risk area. Strong heating is occurring this morning, with
dewpoints in the 50s over most of this region. Present indications
are that scattered fast-moving cells will form over the higher
terrain throughout this region, and along a cold front moving into
NV/ID. Multiple clusters of strong/severe storms may persist
through the afternoon and evening. Large hail and damaging wind
gusts will be the main threats.
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NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 0100Z