U.S. Severe Weather Forecast (Convective Outlook)

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acus01 kwns 191615 
swody1 
Storm Prediction Center ac 191613 


Day 1 convective outlook 
National Weather Service Storm Prediction Center Norman OK 
1013 am CST Friday Dec 19 2014 


Valid 191630z - 201200z 


..no severe thunderstorm areas forecast... 


... 
isolated thunderstorms will remain possible into this evening across 
parts of the western and central Gulf Coast states. 


..wrn/central Gulf Coast... 
Low-amplitude shortwave trough over East Texas will rapidly progress east/NE 
towards the southern Appalachians through early Sat. With only modest 
low-level warm air advection atop a near-surface stable layer and the reinforcement 
of static stability with a broad stratiform rainfall 
shield...quasi-stationary front across the northwest/N-cntrl Gulf should 
remain offshore except near the mouth of the MS river as a weak 
cyclone moves along the frontal zone. 


Thunderstorm coverage has already substantially diminished compared to 
earlier this morning. Given the modest large-scale ascent and dearth 
of elevated buoyancy/instability sampled in 12z lch/shv/lix 
radiosonde observations...prospects for inland thunderstorm activity appear rather limited. 
Renewed thunderstorm development will remain possible along the offshore 
frontal zone...with the northern periphery of scant buoyancy supporting a 
risk for sporadic lightning strikes over parts of the coastal plain. 


.Grams/corfidi/Gleason.. 12/19/2014 

Mesoscale Discussion


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acus11 kwns 170924 
sels mesoscale discussion 
Storm Prediction Center mesoscale discussion 170924 
caz000-171130- 


Mesoscale discussion 1980 
National Weather Service Storm Prediction Center Norman OK 
0324 am CST Wednesday Dec 17 2014 


Areas affected...portions of coastal Southern California 


Concerning...severe potential...watch unlikely 


Valid 170924z - 171130z 


Probability of watch issuance...5 percent 


Summary...limited risk for a marginally damaging wind gust or two -- 
or possibly a brief/weak tornado -- is evident over coastal portions 
of Ventura/Los Angeles/Orange counties in Southern California early this morning. 
Ww issuance will not be required. 


Discussion...latest radar and lightning data depict a small cluster 
of thunderstorms crossing The Channel islands area and adjacent 
coastal Southern California at this time...coincident with a middle-level cyclonic 
circulation center moving east-southeastward across this area per WV loop. 


Despite surface dewpoints only in the low 50s...relatively steep 
lapse rates through the lower and middle troposphere are 
contributing to marginal cape /a few hundred j/kg per objective 
analyses/...thus fueling updrafts which are extending through the 
mixed-phase /-20 c/ layer. 


While area vwps depict relatively modest /20 to 30 knots/ swlys through 
500 mb...backed/sely low-level winds ahead of the storms seem to be 
aiding in occasional weak/short-lived low-level circulations in 
stronger cells -- as observed by kvtx /Ventura/ WSR-88D. Given the 
sustained/weakly rotating storms...a very isolated/low-end severe 
risk may spread onshore over the next couple of hours. With that 
said...any risk for strong winds and/or a brief/weak tornado should 
remain well below thresholds required to consider ww issuance. 


.Goss/Thompson.. 12/17/2014 


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


Attention...WFO...sgx...lox... 


Latitude...Lon 33831966 34421979 34531953 34431907 34101833 33781773 
33401780 33231830 33171948 33391973 33831966