U.S. Severe Weather Forecast (Convective Outlook)

Day Three

acus02 kwns 180345 
Storm Prediction Center ac 180344 

Day 2 convective outlook 
National Weather Service Storm Prediction Center Norman OK 
1044 PM CDT Tue Oct 17 2017 

Valid 191200z - 201200z 

..no severe thunderstorm areas forecast... 

thunderstorm probabilities will be greatest across the southern 
rockies, along the Pacific northwest coast, and over parts of 


Dry and stable conditions will exist across much of the contiguous 
US Thursday though three distinct areas of the country will have 
some threat for thunderstorms. 

1) southern rockies region - several low-latitude disturbances will 
traverse the international border over the next few days. These 
features should encourage higher precipitable water air mass to spread across 
northern Mexico into nm and the adjacent High Plains. As a result, 
convection is expected to develop across this region as instability 
increases ahead of short wave. Thunderstorms that form over nm will 
spread toward the Texas South Plains during the evening aided by 
nocturnal increase in low level jet across this region after dark. 

2) Pacific northwest - profiles are expected to cool significantly along 
the Pacific northwest coast as a strong trough moves inland around 20/03z. 
Primary threat for lightning will be with Post-frontal convection 
influenced by relatively more buoyant onshore flow. 

3) Florida - upper trough will move off the Florida coast early in the period 
and heights will rise slowly as ridge builds toward the state. 
Large-scale surface pattern will change little over the next few 
days with deep easterly flow expected to continue due to dominant 
surface ridge anchored over the southern Appalachians. Showers will 
focus along the East Coast and sufficient buoyancy should exist for 
at least a threat for lightning with the strongest updrafts. 

.Darrow.. 10/18/2017