U.S. Severe Weather Forecast (Konvektiivne väljavaade)

Day Three

acus01 kwns 250043 
Storm Prediction Center ac 250042 

Day 1 convective outlook 
National Weather Service Storm Prediction Center Norman OK 
0642 PM CST Sat Feb 24 2018 

Valid 250100z - 251200z 

..there is an enhanced risk of severe thunderstorms across western 
Kentucky and western Tennessee...including far southern Illinois and in... 

..there is a slight risk of severe thunderstorms from the arklamiss 
into southern in... 

..there is a marginal risk of severe thunderstorms from eastern Texas 
to the Ohio Valley... 

Damaging wind and a few tornadoes remain possible mainly over 
western Tennessee and Kentucky this evening, possibly as far north 
as far southern Indiana, with other severe storms extending from the 
arklamiss toward the Ohio Valley. 

A strong, progressive shortwave trough will move from the MO valley 
toward the Great Lakes through tonight, with a deepening surface low 
pivoting north from near St. Louis toward Lake Superior by Sunday 
morning. A zone of pressure falls ahead of a cold front will also 
extend southward from this low, with tail end affecting the Ohio and 
Tennessee valleys this evening. Meanwhile, a narrow ribbon of mid 60s f 
dewpoint will be maintained across the lower MS valley, with a 
gradual northward progression across the enhanced risk area. Very 
strong wind shear exists near the surface trough, supportive of 
severe weather including a few tornadoes and damaging winds. 

..lower MS valley across the Tennessee and Ohio valleys... 
A vigorous line of severe storms currently extends from the MO 
bootheel southward across far eastern AR, and this activity will 
remain a threat for several hours as it moves into western Kentucky and 
Tennessee. These areas currently have large-scale support with substantial 
pressure falls and a strong low-level jet, in addition to the 
moisture and instability axis. Sometime this evening, this activity 
will decrease in intensity as the upper support pulls north. 
However, a cold front will still progress slowly across the 
remainder of la, MS, and al, with a few severe reports possible. 

For more information, see mesoscale discussions 94 and 95. 

.Jewell.. 02/25/2018 


Mesoscale Discussion

acus11 kwns 250359 
sels mesoscale discussion 
Storm Prediction Center mesoscale discussion 250359 

Mesoscale discussion 0097 
National Weather Service Storm Prediction Center Norman OK 
0959 PM CST Sat Feb 24 2018 

Areas affected...middle Tennessee...eastern Kentucky and parts of 
adjacent southern Ohio and West Virginia 

Concerning...Tornado Watch 6... 

Valid 250359z - 250530z 

The severe weather threat for Tornado Watch 6 continues. 

Summary...a risk for severe weather continues, but this threat is in 
the process of becoming increasingly marginal, and a new watch is 
not anticipated. 

Discussion...overall, even the most vigorous convection is becoming 
generally low-topped as associated large-scale forcing for ascent 
spreads toward the upper Ohio Valley/central Appalachians. 
Lightning has diminished considerably further in the past couple of 
hours, and these trends seem likely to continue into and through the 
1-4 am EST time frame. Although the surface warm front has advanced 
into the vicinity of the Ohio River, the boundary layer ahead of the 
convective line becomes progressively cooler and drier eastward into 
the Cumberland Plateau. Further potential for tornadoes seems 
rather limited, but downward mixing of stronger momentum could 
continue to contribute to sporadic damaging wind gusts at least 
another couple of hours. 

.Kerr.. 02/25/2018 

..please see www.Spc.NOAA.Gov for graphic product... 


Latitude...Lon 38338497 38958414 39158314 38588214 37398295 36018475 
35388588 35308650 35768705 37038585 37878545 38338497