- Day Three
acus02 kwns 030600
Storm Prediction Center ac 030559
Day 2 convective outlook
National Weather Service Storm Prediction Center Norman OK
1259 am CDT Monday Aug 03 2015
Valid 041200z - 051200z
..there is a marginal risk of severe thunderstorms from portions of the plains
through the middle MS valley...Tennessee Valley and southern portion of the Ohio
..there is a marginal risk of severe thunderstorms from portions of the middle
Atlantic into New England...
A few strong to severe storms will be possible from the Central High
plains through the middle Mississippi Valley and Tennessee Valley
areas. Other strong storms may occur from a portion of New England
into the middle Atlantic region.
Blocking pattern will persist through Tuesday with upper low
remaining in place from the Ohio Valley into the northestern states. A series
of impulses will rotate through this feature. At least a couple of
vorticity maxima will undercut western U.S. Upper ridge and continue
through the central and northern plains and middle MS valley areas. At the surface
a cold front will move through remainder of New England with
trailing portions of this boundary extending southwestward through the middle
Atlantic and then westward into the Central Plains.
..cntrl/Southern Plains through middle MS valley and Tennessee/Ohio Valley areas...
Areas of thunderstorms should be ongoing 12z Tuesday within zone of
ascent north of the quasi-stationary front from the middle MS valley
westward into the Central Plains. Other thunderstorms should be in progress
from western Kansas nwwd into the central/northern rockies in association with
ascent attending a couple of slow moving shortwave troughs that will
undercut upper ridge. Potential exists for the atmosphere to become
moderately unstable within portions of the moist warm sector...but
areas of widespread clouds and ongoing thunderstorms lower
confidence in where the best destabilization will occur. Most of
this region will remain SW of stronger winds aloft with vertical
shear supportive of multicells. An exception will be possibly over
western Kansas where models indicate east-southeasterly winds will develop north of weak
surface low and beneath slightly stronger westerly winds aloft within base of
a low-amplitude shortwave trough. Where sufficient boundary layer
warming occurs...storms should undergo some intensification during
the afternoon and pose a threat for mainly a few instances of
damaging wind. Due to the potential mitigating influence of ongoing
storms on the thermodynamic environment...will maintain the marginal
risk category this update.
Farther east into the middle MS and Tennessee/Ohio valleys additional storms
should develop in vicinity of the stalled front as the atmosphere
destabilizes. The strongest diabatic warming and destabilization are
expected from portions of Tennessee and southern Kentucky. This region will also
reside south of the stronger winds aloft...but the thermodynamic
environment may support a few instances of mainly damaging wind
during the afternoon.
..New England through the middle Atlantic area...
Moderate instability is possible ahead of cold front Tuesday over
portions of New England and southward into the middle Atlantic. Storms are
expected to redevelop as surface layer destabilizes. Some risk will
exist for a few strong to severe storms from late morning through
middle afternoon...especially given favorable wind profiles in this
region. However...overall magnitude of threat will depend on frontal
timing and extent of clouds and early convection which remains
uncertain at this time.