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Day 1 Outlook Convective Tornado
Hail Wind
Categorical Day1 1200Z Outlook
  
Images courtesy of the NWS Storm Prediction Center
 Forecast Discussion


000
ACUS01 KWNS 240523
SWODY1
SPC AC 240522

Day 1 Convective Outlook  
NWS Storm Prediction Center Norman OK
1222 AM CDT Mon Sep 24 2018

Valid 241200Z - 251200Z

...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
THE TENNESSEE AND OHIO VALLEYS...

...SUMMARY...
Isolated severe storms are possible during the day across parts of
the Tennessee and Ohio Valleys, with a few strong storms across the
northern High Plains and upper Mississippi Valley.

...Synopsis...
An upper trough will move from the northern and central Rockies into
the Plains, with a lead wave across the Dakotas and MN, and a
secondary wave developing over WY during the day. A weak surface
trough will stretch from central MN into the central High Plains by
late afternoon, with a relatively late attempt at low-level moisture
return ahead of the wind shift. To the east, a weaker upper
disturbance will move from the lower MS Valley toward the OH Valley
during the day, with some strengthening in the low-level wind fields
as a warm front lifts north to the OH River.

...TN/OH Valleys...
Rain and thunderstorms are likely to be ongoing early Monday across
western TN and KY in association with an area of warm advection. The
effective warm front will lift north toward the OH River during the
day, with southerly 850 mb winds on the order of 30 kt. While winds
aloft will not be strong, upper 60s to near 70 F dewpoints and
effective SRH of 100-200 m2/s2 may support a few embedded strong
storms capable of marginal wind gusts, possibly enhanced by
rotation.

...Southeast WY into western NE and northeast CO...
Surface winds will gradually veer from northwest to easterly during
the day, with some weak westward advection of moisture possible.
This, along with heating, will occur beneath cold temperatures aloft
related to the upper trough, resulting in a few hundred J/kg of
MUCAPE. Strong speed shear with height will be present, and by late
afternoon, isolated cells are expected to form over WY. Some of
these cells could contain hail, but the threat of severe weather
appears low at this time due to limited instability.

...Upper MS Valley...
Substantial cooling aloft will occur through the period as a cold
front moves from the eastern Dakotas into MN during the day. The air
mass will only be weakly unstable, and capped ahead of the front.
However, lift along and behind the front should result in scattered
storms by afternoon. Small hail is possible, but the severe threat
appears low.

..Jewell/Squitieri.. 09/24/2018

$$