Severe Storm Outlook Narrative (AC)
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000
ACUS11 KWNS 211814
SWOMCD
SPC MCD 211813
VAZ000-NCZ000-WVZ000-TNZ000-KYZ000-GAZ000-ALZ000-MSZ000-212015-

Mesoscale Discussion 0537
NWS Storm Prediction Center Norman OK
0113 PM CDT Fri Apr 21 2017

Areas affected...Far northern Alabama...much of Tennessee...western
North Carolina...western Virginia...and southeastern Kentucky

Concerning...Severe potential...Watch unlikely

Valid 211813Z - 212015Z

Probability of Watch Issuance...20 percent

SUMMARY...Scattered thunderstorms will pose a threat for sporadic
hail/damaging wind gusts this afternoon and early evening.  A WW is
not anticipated for this activity.

DISCUSSION...Scattered convection continues to increase in coverage
within broadly confluent, weakly capped regime ahead of a
slow-moving cold front.  These storms are in a weakly unstable
airmass, with deep shear (30-35 kts) on the lower margins for
organized convection.  Despite the marginal shear, a couple of weak
supercell structures have been observed on radar within the past
hour, particularly with updrafts interacting with the slow-moving
boundary.  Steepening low-level lapse rates within the
pre-convective airmass will foster an isolated damaging wind threat
- and this threat may be locally enhanced near any brief supercell
structures that can evolve.  Given the instability profiles, hail
approaching 1" in diameter may also occur with the strongest cores.

Given the marginal nature of the threat, a weather watch issuance is
not anticipated.

..Cook/Goss.. 04/21/2017

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

ATTN...WFO...RNK...RLX...GSP...MRX...JKL...FFC...LMK...OHX...
HUN...MEG...

LAT...LON   35068839 35648789 36058675 36448564 36828452 37208340
            37328284 37368147 36898046 36178054 35638127 35258224
            35088316 34918484 34618692 34558836 34608865 35068839




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