U.S. Severe Weather Forecast (Convective Outlook)

Day Three

acus01 kwns 121948 
Storm Prediction Center ac 121946 

Day 1 convective outlook 
National Weather Service Storm Prediction Center Norman OK 
0146 PM CST Mon Nov 12 2018 

Valid 122000z - 131200z 

..there is a slight risk of severe thunderstorms late this 
afternoon across parts of southeast Louisiana into southern Alabama 
and the western Florida Panhandle...and tonight across parts of far 
eastern North Carolina... 

A few severe storms remain possible late this afternoon across the 
northeast Gulf coastal region, and tonight over the coastal 

..20z outlook update... 
Some changes to categorical and probabilistic outlook lines have 
been made, mostly to account for the progression of synoptic and 
sub-synoptic features contributing to convective development. 

Stronger lower/mid tropospheric wind fields are in the process of 
spreading well inland, to the cool side of the surface frontal zone 
near the northeastern Gulf Coast, as one subtle mid-level 
perturbation accelerates into/through the Ohio Valley, ahead of 
increasingly amplified larger-scale troughing within the westerlies. 
Vwp data indicate considerable recent veering and weakening of near 
surface flow across southeastern Louisiana into Mississippi, 
suggesting diminishing severe weather probabilities. Shrinking 
low-level hodographs across the remainder of the northeastern Gulf 
Coast is expected to contribute to similar trends through early 

.Kerr.. 11/12/2018 

Previous discussion... /issued 1018 am CST Mon Nov 12 2018/ 

..southeast la to the Florida Panhandle... 
Morning water vapor imagery shows a strong upper trough digging into 
the Southern Plains. A warm front is moving slowly inland across 
southeast la, and lies along the immediate coast of MS/Alabama and the 
western Florida Panhandle. 12z model guidance continues to suggest that 
scattered thunderstorms will be in vicinity of the front through the 
afternoon and evening, with a few rotating storms likely. Those 
storms along and south of the warm front may be capable of locally 
damaging wind gusts and/or a tornado or two. 

..eastern Carolinas... 
Gradual moistening and destabilization is expected over coastal 
SC/NC through this forecast period as low-level cyclogenesis occurs. 
By late tonight, mid-upper 60s dewpoints and the potential for 
surface-based convection is expected along the immediate NC coast. 
12z href/hrrr and other models show a cluster of thunderstorms 
affecting this area after 06z, with low-level shear profiles 
supportive of severe storms capable of damaging winds and perhaps a 


Mesoscale Discussion

acus11 kwns 122151 
sels mesoscale discussion 
Storm Prediction Center mesoscale discussion 122151 

Mesoscale discussion 1639 
National Weather Service Storm Prediction Center Norman OK 
0351 PM CST Mon Nov 12 2018 

Areas affected...southern Alabama into the Florida Panhandle 

Concerning...Tornado Watch 427... 

Valid 122151z - 122345z 

The severe weather threat for Tornado Watch 427 continues. 

Summary...a brief tornado or strong wind gusts remain possible 
across eastern portions of the watch area, from southern Alabama 
into the Florida Panhandle, but the overall threat for severe 
weather is likely to wane. 

Discussion...a broad zone of rain and thunderstorms persists ahead 
of a cold front from the mouth of the MS river into southern al, in 
a zone of low-level warm advection supported by 30-40 kt 
southwesterly 850 mb flow. Low-level winds will continue to veer 
with time as the strongest lift shifts north of the region. For the 
near-term, a localized area of 200-300 m2/s2 effective srh exists in 
the vicinity of a warm front across the Florida Panhandle and southeast 
Alabama. The vwp at evx radar does show sufficient shear to support a 
supercell, though the large-scale pattern with a positive-tilt 
trough and lack of heating is tending to minimize coverage of the 
stronger storms. As such, only isolated severe wind gusts or perhaps 
a brief tornado are expected, and a new watch may not be required. 

.Jewell.. 11/12/2018 

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


Latitude...Lon 29768537 30208615 30268667 30388704 30938716 31528643 
31668589 31678549 31608523 31238506 30758491 30328503 
29838501 29698507 29768537