SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0256 PM CDT Wed Apr 06 2022
Valid 062000Z - 071200Z
...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
THE SOUTHEAST AND SOUTHERN APPALACHIANS VICINITY...
...SUMMARY...
Severe thunderstorms capable of producing swaths of damaging gusts,
large hail, and a few tornadoes are expected across the Southeast
States and near the southern Appalachians late this afternoon into
this evening.
...20Z Update...
The Marginal Risk and associated hazard probabilities have been
trimmed from the west based on the progression of the cold front,
but otherwise no major changes have been made to the outlook. The
scenario remains complex, with thunderstorms gradually increasing in
coverage and intensity across parts of GA within a weak warm
advection regime, as well as across parts of AL along the cold front
and separately along a prefrontal trough. Additional thunderstorm
development is expected later this afternoon into the early evening
into parts of northeast AL, northwest GA, middle/eastern TN, and
eastern KY along the cold front. Hail, damaging winds, and a few
tornadoes will be possible with the strongest storms across the
region.
See MCD 425 for additional information regarding the short-term
severe threat in GA, and the previous outlook discussion below for
more information regarding other areas.
..Dean.. 04/06/2022
.PREV DISCUSSION... /ISSUED 1112 AM CDT Wed Apr 06 2022/
...Southeast/Southern Appalachians ...
A complex scenario is expected to evolve today across the Southeast
states, with multiple instigators in place for convective
initiation. Recent surface analysis places a remnant outflow
boundary from about 15 miles north of AUO in east-central AL
east-northeastward across central GA to AGS. Some deeper cumulus and
a few lightning flashes have been noted along this boundary over the
past hour amid persistent southwesterly flow and limited low-level
moisture convergence. A second feature is the approaching cold
front, which currently extends from western TN back southwestward
into far southern AR. A well-defined gravity wave precedes this
front, with the leading edge of this wave currently extended from
middle TN southwestward through far northwest AL and central MS.
Lastly, a compact shortwave trough just off the LA coast is readily
apparent in recent water vapor imagery.
All of these features will result in the potential for complex
convective evolution within the moist and buoyant air mass over the
Southeast today. Current expectation is for initial development
across central AL along and ahead of the gravity wave this
afternoon. Additional development appears possible within the warm
sector across central GA as well, particularly later into the
afternoon as the gravity wave approaches. Furthermore, in situ
initiation is also possible along the outflow boundary. All this
development appears likely to occur around the same time this
afternoon, with more of a linear mode favored on the gravity wave
and more cellular development ahead of it. Thereafter, the outflow
could then act as a corridor for further storm
intensification/organization as all of these thunderstorms move
eastward/northeastward. All severe hazards are possible with this
evolution. Relatively dry mid-levels will contribute to an
outflow-dominant storm structure within most of the cellular
development. Steep mid-level lapse rates will promote hail in any
robust updrafts. Veering low-level flow with height, while not
overly strong, is strong enough to support the potential for QLCS
tornadoes.
Farther north (from middle TN into the southern Appalachians),
initiation appears more probable along the cold front itself, and
not the preceding gravity wave. Clearing is already occurring across
parts of middle TN and the expectation is for moderate buoyancy to
develop ahead of the front, with initial scattered development
across middle TN before becoming more widespread over eastern TN and
adjacent parts of northeast AL/northwest GA and eastern KY. As with
areas south, all severe hazards are possible. Given the strong
mid-level flow, hail is expected to be a risk throughout the
afternoon and evening. Damaging wind gusts are possible within any
bowing segments and a tornado or two may also occur, particularly if
a robust updraft can mature ahead of main line of storms.
Read more CHECK UPDATE ZOOM GRAPHIC
http://dlvr.it/SN6DJJ
