Mesoscale Discussion 183

Issued

Mar 16, 2021, 2:54 AM CDT (07:54 UTC)

Expired

Mar 16, 2021, 5:30 AM CDT

In force

3 hr

Issued by

the Storm Prediction Center

Concerning

Severe potential...watch unlikely

Chance of a watch

20%

The Birmingham radar (KBMX), 62 km from the middle of the area, began a volume at 07:54 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.

607 
ACUS11 KWNS 160755
SWOMCD
SPC MCD 160754 
ALZ000-TNZ000-161030-

Mesoscale Discussion 0183
NWS Storm Prediction Center Norman OK
0254 AM CDT Tue Mar 16 2021

Areas affected...Portions of AL into southern middle TN

Concerning...Severe potential...Watch unlikely 

Valid 160754Z - 161030Z

Probability of Watch Issuance...20 percent

SUMMARY...A rather isolated severe threat may continue early this
morning. Watch issuance remains unlikely.

DISCUSSION...Ascent associated with a weak perturbation embedded
within mid-level southwesterly flow has encouraged an uptick in
convective coverage across AL and southern middle TN over the past
hour or two. A weak surface boundary is present across northern AL,
separating mid 60s dewpoints from upper 50s farther north into
southern middle TN. Any storms that form or persist to the north of
this boundary will likely remain elevated, with mainly an isolated
hail risk. Farther south into central AL along/south of the
boundary, there should be a better potential for near-surface-based
storms, as MLCAPE around 250-750 J/kg is likely present. Recent VWPs
from KBMX show a veering and strengthening wind profile through
mid-levels, although there is some weakness in the flow in roughly
the 2-3 km AGL layer. Effective SRH in the 100-150 m2/s2 range could
potentially support occasional low-level rotation, and a brief
tornado cannot be ruled out. A strong wind gust and marginally
severe hail may also occur with any vigorous updraft given 40-50 kt
of deep-layer shear. Still, the modest large-scale forcing and weak
instability will likely keep the overall severe threat rather
isolated/marginal through the early morning hours as storms develop
eastward. Therefore, watch issuance continues to appear unlikely at
this time.

..Gleason/Thompson.. 03/16/2021

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

ATTN...WFO...MRX...OHX...BMX...HUN...MOB...

LAT...LON   32118840 34118801 34968780 35368725 35488613 35198569
            34808559 33558540 32688625 31958739 31928808 32118840

Mesoscale Discussions in Alabama, 2021Mesoscale Discussions in Tennessee, 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.