Severe Storm Outlook Narrative (AC)
Issued by NWS
ACUS11 KWNS 250250
SPC MCD 250250
Mesoscale Discussion 0209
NWS Storm Prediction Center Norman OK
0850 PM CST Fri Feb 24 2017
Areas affected...Parts of southern/eastern KY...middle/eastern
TN...and northern AL
Concerning...Severe potential...Watch possible
Valid 250250Z - 250415Z
Probability of Watch Issuance...60 percent
SUMMARY...Thunderstorms should continue to increase in coverage
ahead of a cold front, with some threat for large hail and damaging
winds with the strongest storms. Severe thunderstorm watch issuance
is possible if storms strengthen further.
DISCUSSION...A broken line of thunderstorms extends from southern KY
into middle TN and northern AL along a pre-frontal trough as of
0245Z. As large-scale forcing for ascent overspreads this area from
the west with an approaching mid to upper-level trough, convection
should continue to increase in coverage over the next several hours.
02Z RAP mesoanalysis indicates MLCAPE around 500 J/kg is located
across middle TN and surrounding vicinity, as relatively steep
mid-level lapse rates (around 7.5 degrees C/km) are present per the
00Z sounding from Nashville, TN. Even with the limited buoyancy, a
veering wind profile and strong mid-level winds are supporting 40-50
kt of effective bulk shear. An isolated large hail and damaging wind
threat should develop with this broken line of storms through the
remainder of the evening hours, and a severe thunderstorm watch may
be needed if convection continues to strengthen.
...Please see www.spc.noaa.gov for graphic product...
LAT...LON 34878737 35858677 37168538 37188415 36938361 35908454
35008564 34388639 34468709 34878737