U.S. Severe Weather Forecast (Convective Outlook)

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 
northeast states... 

..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 
and Oregon. 

..northeast/mid-Atlantic states... 
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. 

.Guyer.. 05/30/2015