Mesoscale Discussion 1913

Issued

Dec 29, 2016, 1:35 AM CST (07:35 UTC)

Expired

Dec 29, 2016, 3:30 AM CST

In force

115 min

Issued by

the Storm Prediction Center

Chance of a watch

5%

The Jackson/Brandon,MS radar (KDGX), 113 km from the middle of the area, began a volume at 07:37 UTC, the scan nearest the moment this went out.

Open the radar archive at this moment

The archived warnings, watches and discussions in force at that minute are drawn over the scan, this one among them.

082 
ACUS11 KWNS 290736
SWOMCD
SPC MCD 290735 
GAZ000-ALZ000-MSZ000-LAZ000-290930-

Mesoscale Discussion 1913
NWS Storm Prediction Center Norman OK
0135 AM CST Thu Dec 29 2016

Areas affected...Portions of central MS...northern/central AL...and
western GA

Concerning...Severe potential...Watch unlikely 

Valid 290735Z - 290930Z

Probability of Watch Issuance...5 percent

SUMMARY...A marginal threat for strong to locally damaging winds and
perhaps a brief tornado will continue for the next several hours.
Watch issuance is not expected due to the overall isolated severe
risk.

DISCUSSION...07Z surface observations indicate a cold front extends
across northern GA/AL into central MS and northern LA, moving
east/southeast with time. Recent radar imagery shows a broken line
of thunderstorms extending along the front across mainly central MS
and northeastern LA. Overall line motion around 30-40 kt and
velocity data from the KDGX radar suggest isolated strong to locally
damaging wind potential with this broken line as it progresses
southeast across central MS over the next several hours. However,
the thermodynamic environment remains marginal for enhanced winds
within the convective line to reach the surface, as MLCAPE is 500
J/kg or less per 07Z RAP mesoanalysis. Low-level flow is also
generally veered to the southwest based on both surface observations
and the KDGX VWP, with only modest additional veering to westerly at
mid levels. Limited curvature of low-level hodographs suggest the
tornado threat with the main line in MS should be brief and isolated
at most.

Farther east across northern/central AL and western GA, ongoing
showers and thunderstorms appear to be rooted above the surface
given storm motions generally in line with the mean 850-500 mb flow.
It remains unclear if any of these thunderstorms can become
surface-based even with substantial moistening of low levels across
much of central AL over the past few hours, evidenced by the 00Z and
06Z soundings from BMX. Some residual capping around 700 mb may
prove detrimental to updraft accelerations ahead of the approaching
front. Similar to central MS, as the front moves across central AL
and western GA overnight, there may be a marginal threat for
isolated strong to damaging winds, and perhaps a brief tornado.
Regardless, the overall severe threat still appears too marginal to
warrant watch issuance.

..Gleason/Edwards.. 12/29/2016

...Please see www.spc.noaa.gov for graphic product...

ATTN...WFO...FFC...BMX...HUN...MOB...JAN...

LAT...LON   32499176 32609174 32869074 33228988 33658824 34428545
            34028465 33288471 32578645 31918860 31549089 31759180
            32499176

Mesoscale Discussions in Mississippi, 2016Mesoscale Discussions in Alabama, 2016Mesoscale Discussions in Georgia, 2016Every mesoscale discussion in 2016

The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.