U.S. Severe Weather Forecast (Convective Outlook)

Day Three

acus01 kwns 170542 
Storm Prediction Center ac 170540 

Day 1 convective outlook 
National Weather Service Storm Prediction Center Norman OK 
1140 PM CST Tue Jan 16 2018 

Valid 171200z - 181200z 

..no thunderstorm areas forecast... 

thunderstorms are not expected across the U.S. Today or tonight. 

An upper-level trough will move across the eastern U.S. Today as 
another upper-level trough remains in the eastern Pacific. A 
mid-level jet associated with this system will overspread the 
Pacific northwest tonight. Strong large-scale ascent and steep lapse 
rates will be enough for an isolated lightning strike along the 
coast of Washington late in the period. However, thunder coverage is 
not expected to reach the 10 percent threshold. Elsewhere across the 
conus, thunderstorms are not expected today or tonight. 

.Broyles/karstens.. 01/17/2018 


Mesoscale Discussion

acus11 kwns 162321 
sels mesoscale discussion 
Storm Prediction Center mesoscale discussion 162320 

Mesoscale discussion 0029 
National Weather Service Storm Prediction Center Norman OK 
0520 PM CST Tue Jan 16 2018 

Areas affected...middle/Upper Texas coast...southeast la 

Concerning...winter mixed precipitation 

Valid 162320z - 170315z 

Summary...ongoing mixed winter precipitation is expected to persist 
for the next few hours. Primary precipitation type will likely be 

Discussion...regional radar data shows an area of relatively heavier 
precipitation across portions of the middle Texas coast moving 
east-southeastward. Higher reflectivities have been noted across 
portions of Wharton and Fort Bend counties with corresponding lower 
correlation coefficients. This represents a broad area of melting 
hydrometeors, which corroborates the 0 degree c isothermal layer 
from 850-700 mb shown on recent rap forecast soundings. Given the 
presence of this layer, a transition to all snow seems unlikely, 
with the most dominant precipitation type remaining sleet for the 
next few hours. Precipitation will gradually taper off during this 
time, from northwest to southeast, as subsidence and dry air 
advection continue to dry the low-level levels. 

.Mosier.. 01/16/2018 

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


Latitude...Lon 29029662 29889598 30459418 30489280 30079202 29569228 
29789325 29679381 29389480 28659593 29029662