Severe Storm Outlook Narrative (AC)
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000
ACUS01 KWNS 271631
SWODY1
SPC AC 271630

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1130 AM CDT Mon Mar 27 2017

Valid 271630Z - 281200Z

...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS THE
MID-SOUTH AND TN RIVER VALLEY...

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM PORTIONS OF
MS/AL TO THE OH RIVER VALLEY...

...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS THE
MIDDLE OH VALLEY TO LOWER MS VALLEY...

...SUMMARY...
Scattered to numerous severe thunderstorms are expected across the
Lower Mississippi and Ohio Valleys into the Tennessee Valley this
afternoon and evening. Very large hail, damaging winds, and a couple
tornadoes will be possible.

...Lower Ohio/Mississippi River Valleys and Tennessee Valley...
A low-amplitude shortwave trough over the southern MO late this
morning will continue generally eastward and reach the middle OH
River Valley by late tonight. A preceding belt of 40-50 kt
west-southwesterly mid level winds will continue to overspread an
increasingly moist, albeit modestly so, warm sector. Ahead of an
eastward-moving cold front currently across the Ozarks and
Ark-La-Tex, lower/some middle 60s F surface dewpoints will continue
to become increasingly common across eastern AR, northern MS into
western TN, northward into western KY. While warm-sector cloud cover
has remained semi-prevalent thus far, some cloud breaks are noted in
visible satellite imagery an additional thinning seems likely in
concert especially with the eastward-spread mid/high-level dry slot
as per water vapor satellite imagery.

Linearly organized convection across far northeast AR/far southeast
MO late this morning should continue to spread east-northeastward
and increase in coverage/intensify into northwest TN and
western/central KY as the downstream air mass continues to moisten
and destabilize. This activity will pose a damaging wind and severe
hail risk, although a tornado cannot be ruled out. Farther south,
other initially more discrete storms should develop within the warm
sector this afternoon across additional portions of TN, far eastern
AR, northern MS and eventually northwest AL later this
afternoon/evening. Here, supercell-favorable wind profiles and steep
mid-level lapse rates as noted per 12Z observed soundings will
support large hail potential. A few tornadoes also appear possible,
particularly around mid/late afternoon into early evening across
western/middle portions of TN and northern MS and northwest AL. In
this corridor, a modest westerly component of the mid-level winds
will coincide with modestly strong low-level shear/SRH.

..Guyer/Mosier.. 03/27/2017

$$



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