Charlotte, NC...Nashville, TN...Virginia Beach, VA...Raleigh, NC...Norfolk, VA...
Probabilistic Tornado Graphic
Probability of a tornado within 25 miles of a point. Hatched Area: 10% or greater probability of EF2 - EF5 tornadoes within 25 miles of a point.
Day 1 Tornado Risk
Area (sq. mi.)
Some Larger Population Centers in Risk Area
Philadelphia, PA...Baltimore, MD...Washington, DC...Oklahoma City, OK...Arlington, VA...
Probabilistic Damaging Wind Graphic
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.
Nashville, TN...Virginia Beach, VA...Raleigh, NC...Norfolk, VA...Greensboro, NC...
Probabilistic Large Hail Graphic
Probability of hail 1" or larger within 25 miles of a point. Hatched Area: 10% or greater probability of hail 2" or larger within 25 miles of a point.
Day 1 Hail Risk
Area (sq. mi.)
Some Larger Population Centers in Risk Area
Dallas, TX...Fort Worth, TX...Baltimore, MD...Washington, DC...Oklahoma City, OK...
Memphis, TN...Virginia Beach, VA...Norfolk, VA...Chesapeake, VA...Shreveport, LA...
SPC AC 231256
Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0756 AM CDT Sat Jun 23 2018
Valid 231300Z - 241200Z
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM THE SOUTHERN
PLAINS THROUGH THE SOUTHEAST STATES AND OVER THE MIDDLE ATLANTIC
Scattered severe thunderstorms are expected especially this
afternoon and evening from the southern Plains to the lower
Mississippi Valley and a portion of the Southeast States. Other
severe storms are expected over the Middle Atlantic region. More
isolated strong to severe storms might occur over a portion of the
central and northern Plains.
Persistent regenerative convection and its related cold pool across
Oklahoma into far north Texas has continued to reinforce a roughly
west/east-oriented frontal zone across the region. This effective
front may transition a little northward later today although its
latitudinal location later today is a bit uncertain given the
persistence of early day convection. Along/south of this boundary,
and as far west as a weak surface wave and dryline/surface trough
across west-central/western north Texas, the air mass should become
moderately unstable by peak heating with 2000-4000 J/kg MLCAPE
possible. Owing to hot surface temperatures and modest convergence,
isolated to widely scattered thunderstorm development around late
afternoon appears most probable across the Low Rolling Plains
vicinity of west/north Texas and possibly into southwest Oklahoma,
with greater uncertainties for surface-based/diurnally driven
development north/northeastward into other parts of Oklahoma given
unclear air mass characteristics/recovery.
Additional storms may develop farther east-northeast within the
frontal zone during the evening as the southerly low-level jet
strengthens. A belt of modest winds aloft with 25-30 kt at 500 mb
will result in 35-40 kt effective bulk shear near/north of the front
where surface winds will remain backed to easterly. Weaker shear
will reside in warm sector. Both multicell and some supercell
structures will be possible with damaging wind and large hail the
main threats from late afternoon into the evening.
...Deep South from the Mississippi River to Georgia/South
A MCV appears to be aiding the eastward-persistence of an MCS from
eastern Arkansas into northern Mississippi/southwest Tennessee early
this morning, while MCS-preceding storms have also increased across
northeast Mississippi into northern Alabama. For short-term details,
see Mesoscale Discussion 835. The MCV and the modest outflow-related
cold pool that accompanies it should focus additional development
during the day within a destabilizing boundary layer with up to 2500
J/kg MLCAPE possible. A belt of stronger winds aloft accompanying
the MCV/shortwave trough will aid storm organization and the
environment appears supportive of sub-regional corridors of damaging
winds through the afternoon into early/mid evening, perhaps as far
east as parts of South Carolina.
A warm front will lift north through Virginia into Pennsylvania
during the day ahead of a cold front accompanying a shortwave
trough. Diabatic warming of the moist warm sector will result in
moderate instability with upwards of 2000-2500 J/kg MLCAPE possible
especially from southeast Virginia through the Delmarva into
southern New Jersey. A belt of stronger winds aloft will accompany
the upper low as it shifts northeast and transitions to an open
wave. Storms are expected to develop over the higher terrain with a
lee trough across central Virginia also a focus for development. A
few splitting supercells will be possible as effective bulk shear
increases to 30-40 kt, with storms also organizing into broken bands
as they develop east-northeastward. Damaging wind will be the main
threat, but some hail will also be possible and a brief tornado
cannot be ruled out, particularly with any storms interacting with
the warm front where low-level/deep-layer shear will be regionally
...Wyoming/central High Plains to Middle Missouri River Valley...
Ascent accompanying a shortwave trough moving southeast through the
northern Rockies and diabatic heating will promote increasing
thunderstorm development over the higher terrain of Wyoming into the
broader north-central High Plains this afternoon. High based storms
capable of downburst winds and severe hail appears to be the main
Farther east across South Dakota into eastern Nebraska, a surface
trough accompanying a lead shortwave trough will provide a focus for
storm development during the afternoon. Modest winds aloft will
support multicell storm modes with a few instances of marginally
severe hail and gusty winds possible.
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