srainhoutx wrote:The Storm Prediction Center Day 2 Outlook continues the Slight Risk for severe thunderstorms tomorrow morning. In their discussion, the SPC believes conditions from the Upper Texas Coast on N and E remain favorable for large hail, damaging winds and isolated tornadoes.
the updated discussion
spc ac 261725
day 2 convective outlook
nws storm prediction center norman ok
1225 pm cdt tue apr 26 2016
valid 271200z - 281200z
...there is a slgt risk of svr tstms from ern tx through a portion
of the lower to middle ms valley and wrn tn valley regions...
...there is a mrgl risk of svr tstms from ern tx through the lower
to middle ms valley...tn/oh valleys...and mid-atlantic...
...summary...
strong to severe thunderstorms will be possible wednesday from the
middle and lower mississippi valley...western tennessee valley into
eastern texas.
...synopsis...
negatively-tilted shortwave trough is expected to move slowly from
cntrl plains newd through the mid mo valley during the period while
maturing. moderately strong mid-level flow associated with the
shortwave trough will spread ewd through the ozark plateau and
mid/lwr ms valleys. farther w...a strong shortwave trough will dig
swd along the w coast...reaching srn ca by 12z thu.
at the surface...low associated with the cntrl plains shortwave is
expected to move only slightly ewd from its position at the
beginning of the period -- over cntrl neb/ks border. pacific cold
front/dryline will extend swd from the low across cntrl ok and into
cntrl tx at 12z wed...moving slowly ewd throughout the day. at
00z/thu...this front is expected to extend from the triple point
over n-cntrl mo sswwd through the arklatex and into se tx.
...e tx ewd/newd through lwr and mid ms valleys...
convection is expected to be ongoing at the beginning of the
period...likely extending from n-cntrl ar swwd to the upper tx
coast. this convective line is expected to persist as it continues
ewd across the lwr ms valley during the morning. for most of the
morning...destabilization downstream of this initial line will be
difficult given the time of day and extensive cloudiness. only
isolated svr is anticipated. some additional tstm activity...with
the possibility of re-intensification...is possible as the line
continues ewd into al but the lack of large-scale forcing for ascent
and generally weak shear should keep any svr threat isolated.
environment behind this initial line...from the mid ms valley swwd
towards the upper tx coast...is expected to destabilize ahead of the
approaching dryline. combination of convergence along the dryline
and weak large-scale forcing for ascent within the unstable
environment will likely result in convective initiation across much
of the region. warm and moist surface conditions beneath steep
mid-level lapse rates may result in mlcape near 2000-2500 j per kg.
additionally...increased mid-level flow will contribute to 0-6 km
bulk shear from 40-50 kt. this type of environment will support
supercells capable of all hazards...although large hail appears to
be the primary severe threat. uncertainties regarding convective
evolution of the early day storms and extent of afternoon
destabilization in their wake remains too high to introduce any
higher probabilities with this forecast.
...mid/lwr mo river valley...
several rounds of tstms are possible across the region wednesday.
potential for some surface-based development exists during the
afternoon as the boundary layer destabilizes and forcing for ascent
persists. primary severe threat is large hail...although sely
surface winds near the boundary may provide sufficient low-level
shear for a tornado threat with any storms that remain surface-based
for a sufficient duration.
...oh valley/mid-atlantic...
tstms are expected to develop along the weak frontal zone extending
from the low over the mid mo valley ewd to nrn nc. shear will be
weak but enough instability will exist to support some isolated hail
and/or damaging wind gusts.
..mosier/guyer.. 04/26/2016