Severe Storm Outlook Narrative (AC)
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ACUS02 KWNS 290544
SWODY2
SPC AC 290543

Day 2 Convective Outlook
NWS Storm Prediction Center Norman OK
1243 AM CDT Wed Mar 29 2017

Valid 301200Z - 311200Z

...THERE IS A MODERATE RISK OF SEVERE THUNDERSTORMS THURSDAY
AFTERNOON AND EVENING OVER PARTS OF NORTHERN MS...WESTERN AND MIDDLE
TN...NORTHWEST AL...AND SOUTHWEST KY...

...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS FROM PARTS OF
CENTRAL MS NORTHWARD INTO SOUTHERN IL/IN...

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER MUCH OF THE
LOWER AND MIDDLE MS VALLEYS...AND INTO THE OH/TN VALLEYS...

...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS OVER MUCH OF THE
LOWER AND MIDDLE MS VALLEYS...AND INTO THE OH/TN VALLEYS...

...SUMMARY...
An active severe weather event is forecast for Thursday over parts
of the middle and lower Mississippi Valley into the Tennessee
Valley.

...Northern MS/Northwest AL/Western and Middle TN/Southwest KY...
A strong upper trough will rotate across the southern/central Plains
today, and into the lower/mid MS Valley on Thursday.  Models suggest
that thunderstorm activity from the Day1 period will be waning in
most areas by Thursday morning, while the primary cold front remains
over central AR/LA.  This should allow for some heating and
destabilization to occur ahead of the front, with re-development of
thunderstorms during the afternoon near the MS River.  A strong
mid-level speed max (50+ knots at 700mb) will rotate across the cold
front during the afternoon, promoting strong low-level and deep
layer vertical shear profiles.  Forecast soundings show 0-3km SRH
values of 200-300 m2/s2 and MLCAPE of 1500 J/kg.  Several 00z cam
solutions that extend into the Day2 period indicate discrete
supercell mode will be preferred with the activity, suggesting a
favorable environment for tornadoes, large hail, and damaging winds.
 Strong tornadoes and very large hail will be possible in the MDT
risk area.  The eastward extent of low level moisture will be a
limiting factor to how far east the significant severe threat will
develop.  Nevertheless, strong to severe storms may reach eastern
KY/TN and parts of AL during the evening.

...MO/IL/IN...
It appears the risk for severe storms will also extend northward
into parts of MO/IL/IN during the day as activity blossoms ahead of
the approaching shortwave trough.  This area will likely experience
more cloud cover on Thursday, limiting the confidence in sufficient
instability.  Nevertheless, hail and damaging wind will be possible
in the stronger cells.

..Hart.. 03/29/2017

$$



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