NOAA Storm Prediction Center

Convective Outlooks

Convective Outlooks
The convective outlooks serve as guidance to the local NWS forecast offices and are used by emergency managers, private sector meteorologists, media, and other weather customers concerned with public safety. Three separate risk areas (slight, moderate, and high) are used to describe the expected coverage and intensity for the categorical severe weather threat on days 1-3 along with severe weather probabilities for the potential threat.

Day 1 Outlook Day 2 Outlook Day 3 Outlook Days 4-8 Outlook

Day 1 Outlook Convective Tornado
Hail Wind
Categorical Day1 0100Z Outlook
  
Images courtesy of the NWS Storm Prediction Center
 Forecast Discussion


000
ACUS01 KWNS 230057
SWODY1
SPC AC 230055

Day 1 Convective Outlook  
NWS Storm Prediction Center Norman OK
0655 PM CST Fri Feb 22 2019

Valid 230100Z - 231200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
THE LOWER MISSISSIPPI VALLEY...

...SUMMARY...
A few severe storms will be possible this evening through tonight
from east Texas across the Lower Mississippi Valley. A tornado/wind
damage threat may develop across parts of northeast Louisiana, far
southeast Arkansas and northwest Mississippi.

...Arklatex/Lower Mississippi Valley...
The latest water vapor imagery shows an amplified upper-level trough
over the southwestern U.S. with anticyclonically curved southwest
mid-level flow over the Great Plains and Mississippi Valley. At the
surface, flow is backed to the southeast and east across much of the
Great Plains and Mississippi Valley. A moist airmass is located
across the central Gulf Coast States where surface dewpoints are in
the upper 60s and lower 70s F. As the upper-level trough approaches
the southern Plains tonight, moisture advection will strengthen
across the lower Mississippi Valley. In response, the 60 degree
isodrosotherm is forecast to move through southeastern Arkansas and
northern Mississippi. As the low-level jet strengthens,
thunderstorms will become increasingly likely along the northern
edge of the moist airmass from southern Arkansas eastward into
northwestern Mississippi. 

RAP and NAM Forecast soundings from Monroe, Louisiana northeastward
to south of Memphis, Tennessee in the 06Z to 12Z timeframe steadily
increase instability with MLCAPE reaching the 500 to 1000 J/kg range
by late in the period. This combined with 45-60 kt of effective
shear will be sufficient for storm rotation with the strongest of
cells that form on the southern edge of any convective cluster.
Those cells which could obtain supercell structure, would be capable
of severe wind gusts, hail and possibly a tornado or two. The
potential would be greatest across far northeast Louisiana, western
to northwest Mississippi and far southeast Arkansas where the models
suggest instability, shear and surface-based convective potential
will be maximized.  Have added a small slight risk for parts of the
lower Mississippi Valley to account for an increased severe threat
mainly from 08Z to 12Z late in the period.

..Broyles.. 02/23/2019

$$