- Day Three
acus02 kwns 300601
Storm Prediction Center ac 300600
Day 2 convective outlook
National Weather Service Storm Prediction Center Norman OK
0100 am CDT Sat may 30 2015
Valid 311200z - 011200z
..there is a marginal risk of severe thunderstorms from south/East Texas to the
..there is a marginal risk of severe thunderstorms across portions of Wyoming/Montana and
the Central High plains...
..there is a marginal risk of severe thunderstorms across portions of Oregon...
strong to severe thunderstorms will be possible across parts of the
northeast states...Appalachians to southern and eastern Texas on
Sunday...in addition to portions of the northern/Central High plains
As a weak upper trough slowly develops eastward...a weak frontal
wave will likely accompany an eastward-moving cold front...with a
front-preceding moist/potentially unstable air mass developing as
far north as PA/southern New York and adjacent parts of New England
along/south of a frontal segment. Particularly east of the surface
low and nearby front extending east-northeastward across the
northeast states/New England...vertical shear will be supportive of
organized storms/potentially a couple of supercells pending at least
modest diurnal destabilization. Isolated damaging winds/marginally
severe hail and potentially a tornado risk will exist. Portions of
the region will be reevaluated for a possible categorical slight
risk upgrade in subsequent outlooks.
..south/East Texas to the Tennessee Valley/central Appalachians...
With a moist air mass preceding a southeastward-moving cold
front...daytime heating should contribute to an intensification of
thunderstorms into the afternoon. While vertical
shear will be weak...sufficient buoyancy could result in some
stronger pulse-type/multicell storms capable of isolated damaging
wind gusts/possibly some hail mainly Sunday afternoon/early evening.
..portions of Montana/Wyoming to Central High plains...
A low-amplitude shortwave trough and a modestly moist
environment...aside from orographic lift/differential heating...are
likely to contribute to thunderstorm development across
southwest/south-central Montana and adjacent parts of Wyoming Sunday
afternoon. Moderate shear/adequate buoyancy and a well-mixed
boundary layer may allow for strong/possibly severe thunderstorms
capable of hail/strong downdraft winds.
Farther east/southeast...other isolated storms should develop Sunday
afternoon across parts of eastern Wyoming/northeast Colorado/Nebraska Panhandle
vicinity with aid of a surface trough/weak upslope
trajectories...with storms subsequently spreading
east/southeastward...possibly evolving into a loosely organized mesoscale convective system
Sunday night with aid of a nocturnally increasing low-level jet.
Isolated instances of severe hail/wind will be possible across the
region particularly Sunday afternoon/evening.
In advance of an approaching shortwave trough...modest
moisture/steepening lapse rates may contribute to some strong storms
particularly across western/central portions of Oregon.