Severe Storm Outlook Narrative (AC)
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399
ACUS11 KWNS 280810
SWOMCD
SPC MCD 280810
ALZ000-MSZ000-ARZ000-LAZ000-281045-

Mesoscale Discussion 0217
NWS Storm Prediction Center Norman OK
0210 AM CST Tue Feb 28 2017

Areas affected...Parts of southeastern AR...northern/central
MS...northwestern LA

Concerning...Severe potential...Watch unlikely

Valid 280810Z - 281045Z

Probability of Watch Issuance...20 percent

SUMMARY...Isolated to widely scattered strong storm development is
possible through the 09-12Z time frame, accompanied by a risk for
severe hail.  The need for a watch is not currently anticipated, but
trends will be monitored.

DISCUSSION...In the presence of rising mid-level (500 mb) heights
and capping associated with warm elevated mixed layer air (based
near 700 mb), the initiation of widespread deep convective
development still seems unlikely.  However, model guidance, in
general, indicates an increase in thunderstorm activity is possible
through the 09-12Z time frame, as far south as the Mississippi Delta
Region.  This appears mostly in response to a forecast strengthening
of southerly low-level flow (40-50+ kt at 850 mb), in a corridor
near/east of the Mississippi River.  This may be accompanied by
sufficient strengthening of ascent associated with warm advection to
overcome inhibition.

If/when storms form, environment profiles appear conducive to at
least some severe weather potential.  Activity likely will be based
above a residual stable near surface layer, but steep mid-level
lapse rates and relatively cool mid/upper levels may be supportive
of the risk for severe hail in the strongest storms, aided by
strong, largely unidirectional shear in the cloud bearing layer.

..Kerr/Thompson.. 02/28/2017

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

ATTN...WFO...BMX...MEG...JAN...LZK...SHV...

LAT...LON   33289229 34629157 34848945 34538884 33248812 32728974
            32539129 33289229




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