Mesoscale Discussion 1968

Issued

Dec 6, 2021, 10:06 AM CST (16:06 UTC)

Expired

Dec 6, 2021, 12:00 PM CST

In force

114 min

Issued by

the Storm Prediction Center

Concerning

Severe potential...watch unlikely

Chance of a watch

20%

The Birmingham radar (KBMX), 103 km from the middle of the area, began a volume at 16:05 UTC, the scan nearest the moment this went out.

Open the radar archive at this moment

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791 
ACUS11 KWNS 061606
SWOMCD
SPC MCD 061606 
GAZ000-ALZ000-MSZ000-LAZ000-061800-

Mesoscale Discussion 1968
NWS Storm Prediction Center Norman OK
1006 AM CST Mon Dec 06 2021

Areas affected...Parts of central and southern Alabama...adjacent
portions of western Georgia...southern Mississippi and adjacent
portions of northeastern Louisiana

Concerning...Severe potential...Watch unlikely 

Valid 061606Z - 061800Z

Probability of Watch Issuance...20 percent

SUMMARY...Thunderstorm activity will continue to develop along and
ahead of a southward advancing cold front through 1-2 PM CST, posing
a risk for a few potentially damaging wind gusts and, perhaps, an
isolated tornado or two.  While the damaging wind/tornado risk
appears low enough that a severe weather watch may not be needed,
trends will continue to be monitored.

DISCUSSION...A mid-level speed maximum (50-60+ kt around 500 mb)
might have contributed to organization of an evolving cluster of
storms that is currently overspreading central Alabama.  By 18-19Z,
this jet streak is forecast to rapidly propagate east-northeastward,
into and through the Georgia and South Carolina piedmont, where weak
lower/mid-tropospheric lapse rates and slow/limited modification of
generally stable boundary-layer conditions appear likely to preclude
an appreciable risk for severe weather.

Models indicate that seasonably moist boundary-layer air will remain
confined to along and ahead of the southward advancing cold front,
across and east-northeast of the lower Mississippi Valley.  Even
here, weak lapse rates are limiting CAPE to 500-1000 J/kg or less. 
Given the lack of stronger potential instability, deep-layer wind
fields and shear appear only marginally supportive of continuing
organized strong thunderstorm development with the potential to
produce a few damaging wind gusts and/or, perhaps, an isolated
tornado.  This is expected to remain generally focused within a
corridor of stronger forcing immediately ahead of the front,
advancing south of the Interstate 20 corridor through early
afternoon, where low-level shear (beneath a 30-40 kt 850 jet axis)
is also strongest.

..Kerr/Hart.. 12/06/2021

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

ATTN...WFO...FFC...BMX...MOB...JAN...LIX...SHV...

LAT...LON   33718684 34038469 32728518 31808699 30998998 31649235
            32818871 33718684

Mesoscale Discussions in Alabama, 2021Mesoscale Discussions in Mississippi, 2021Mesoscale Discussions in Georgia, 2021Every mesoscale discussion in 2021

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.