U.S. Severe Weather Forecast (Convective Outlook)

Day Three

acus01 kwns 191931 
Storm Prediction Center ac 191930 

Day 1 convective outlook 
National Weather Service Storm Prediction Center Norman OK 
0230 PM CDT Fri Oct 19 2018 

Valid 192000z - 201200z 

..no severe thunderstorm areas forecast... 

severe storms are not expected over the U.S. Today. 

..20z outlook update... 
Some changes to the categorical (10 percent probability of) thunder 
line have been made, mostly in an attempt to better account for 
latest observational trends. 

Across Florida, relatively warm layers aloft and weak/negligible 
forcing for ascent probably will continue to minimize the risk for 
thunderstorms. However, the initiation of an isolated thunderstorm 
may not yet be out of the question through around 6-7 PM EDT across 
parts of the Central Peninsula, where boundary layer instability 
(cape up to 1000 j/kg) has become locally maximized. 

.Kerr.. 10/19/2018 

Previous discussion... /issued 1109 am CDT Fri Oct 19 2018/ 

Large-scale trough amplification will occur through tonight over the 
Great Lakes and Midwest. Prevalent cool/stable conditions will 
relegate isolated thunderstorm potential to the southern tier of the 
Continental U.S.. near a remnant baroclinic zone, the most probable area for a 
few thunderstorms will be in the warm advection zone from the middle 
Texas coast northward, with only isolated thunderstorms expected 
farther east along the Gulf Coast into northern Florida. Other elevated 
convection will be possible from northern Mexico into the Texas Big 
Bend vicinity. 


Mesoscale Discussion

acus11 kwns 162228 
sels mesoscale discussion 
Storm Prediction Center mesoscale discussion 162228 

Mesoscale discussion 1587 
National Weather Service Storm Prediction Center Norman OK 
0528 PM CDT Tue Oct 16 2018 

Areas affected...portions of NC/SC 

Concerning...severe potential...watch unlikely 

Valid 162228z - 170100z 

Probability of watch issuance...5 percent 

Summary...strong/gusty winds may occur on an isolated basis through 
the evening. Watch issuance is unlikely. 

Discussion...glancing influence of large-scale ascent associated 
with an upper-level jet over the mid-Atlantic/northeast coupled with 
modest low-level convergence along a stalled front should support 
isolated to scattered convective development through the evening 
across the southern half of NC and parts of SC. This generally 
east-west oriented front will likely serve as a focus for 
thunderstorms, with a couple attempts at convective initiation noted 
recently near gsp in upstate SC. A meso-low noted on 22z surface 
analysis near Fay may also subtly enhance low-level convergence 
along the front in southern NC. 

Some cloud breaks to the south of the front have contributed to 
temperatures in the low 80s at 2228z. A moist-level airmass is also 
present across the warm sector, with dewpoints generally in the 
upper 60s to lower 70s. Daytime heating and plentiful moisture are 
supporting MLCAPE around 250-1000 j/kg, with poor mid-level lapse 
rates limiting even greater destabilization. 40-50+ kt of 
west-southwesterly mid-level flow is present across much of the 
Carolinas, and a strengthening wind profile with height is 
contributing to around 40-50 kt of effective bulk shear. Mid-level 
rotation within thunderstorm updrafts will likely occur given this 
degree of shear, and a couple transient supercells cannot be ruled 
out. A small line segment or thunderstorm cluster will probably 
consolidate along the front as it moves eastward through the 

Even with nocturnal cooling commencing soon, already steepened 
low-level lapse rates should encourage efficient momentum Transfer 
of convective downdrafts to the surface. Isolated strong/gusty winds 
primarily capable of tree damage appear to be the main severe 
threat, but very isolated hail may also occur. Regardless, the 
thermodynamic environment will remain quite marginal, and watch 
issuance is unlikely at this time. 

.Gleason/Edwards.. 10/16/2018 

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


Latitude...Lon 34358191 34878185 35328123 35558022 35557834 35157592 
34857618 34577645 34587693 34367746 34007779 33817793 
33837819 33767854 33437895 34358191